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Hultine KR, Hernández-Hernández T, Williams DG, Albeke SE, Tran N, Puente R, Larios E. Global change impacts on cacti (Cactaceae): current threats, challenges and conservation solutions. Ann Bot 2023; 132:671-683. [PMID: 36861500 PMCID: PMC10799997 DOI: 10.1093/aob/mcad040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 02/10/2023] [Accepted: 03/01/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND The plant family Cactaceae provides some of the most striking examples of adaptive evolution, expressing undeniably the most spectacular New World radiation of succulent plants distributed across arid and semi-arid regions of the Americas. Cacti are widely regarded for their cultural, economic and ecological value, yet they are also recognized as one of the most threatened and endangered taxonomic groups on the planet. SCOPE This paper reviews current threats to species of cacti that have distributions in arid to semi-arid subtropical regions. Our review focuses primarily on four global change forces: (1) increases in atmospheric CO2 concentrations; (2) increases in mean annual temperatures and heat waves; (3) increases in the duration, frequency and intensity of droughts; and (4) and increases in competition and wildfire frequency from invasion by non-native species. We provide a broad range of potential priorities and solutions for stemming the extinction risk of cacti species and populations. CONCLUSIONS Mitigating ongoing and emerging threats to cacti will require not only strong policy initiatives and international cooperation, but also new and creative approaches to conservation. These approaches include determining species at risk from climate extremes, enhancing habitat quality after disturbance, approaches and opportunities for ex situ conservation and restoration, and the potential use of forensic tools for identifying plants that have been removed illegally from the wild and sold on open markets.
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Affiliation(s)
- Kevin R Hultine
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ 85008, USA
| | - Tania Hernández-Hernández
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ 85008, USA
| | - David G Williams
- Department of Botany, University of Wyoming, Laramie, WY 82071, USA
| | - Shannon E Albeke
- Wyoming Geographic Information Science Center, University of Wyoming, Laramie, WY 82071, USA
| | - Newton Tran
- Center of Tree Science, Morton Arboretum, Lisle, IL 60532, USA
| | - Raul Puente
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ 85008, USA
| | - Eugenio Larios
- Programa Educativo de Licenciado en Ecología, Universidad Estatal de Sonora, Hermosillo, Sonora 83100, México
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Majure LC, Murphy TH, Köhler M, Puente R, Hodgson WC. Evolution of the Xerocarpa clade ( Opuntia; Opuntieae): Evidence for the Role of the Grand Canyon in the Biogeographic History of the Iconic Beavertail Cactus and Relatives. Plants (Basel) 2023; 12:2677. [PMID: 37514291 PMCID: PMC10385227 DOI: 10.3390/plants12142677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/08/2023] [Accepted: 07/10/2023] [Indexed: 07/30/2023]
Abstract
The formation of the western North American drylands has led to the evolution of an astounding diversity of species well adapted for such communities. Complex historical patterns often underlie the modern distribution of the flora and fauna of these areas. We investigated the biogeography of a group of desert-adapted prickly pears, known as the Xerocarpa clade, from western North America. The Xerocarpa clade originated in the mid-late Pliocene, likely on the Colorado Plateau, and then moved south into the Mojave, Sonoran, and Chihuahuan deserts, and California montane regions, further diversifying, mostly into the Quaternary. The southward trajectory of the clade was likely greatly influenced by the formation of the Grand Canyon. The synapomorphy of dry fruit presumably impeded the long-distance dispersibility of the beavertail cactus, Opuntia basilaris, while dry, spiny fruit may have enabled O. polyacantha to substantially increase its distribution. Opuntia basilaris evolved a pubescent epidermis, allowing it to invade hotter, drier conditions, while the spine-clothed stems of O. polyacantha may have given it an advantage for increasing its northern range into colder environments. The Xerocarpa clade shows a cold desert origin, and changes in morphological characters have made these sister taxa well adapted for invading broadscale, but oftentimes contrasting habitats.
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Affiliation(s)
- Lucas C Majure
- University of Florida Herbarium (FLAS), Florida Museum, Department of Natural History, University of Florida, Gainesville, FL 32611, USA
- Department of Research and Conservation, Desert Botanical Garden, Phoenix, AZ 85008, USA
| | - Thomas H Murphy
- University of Florida Herbarium (FLAS), Florida Museum, Department of Natural History, University of Florida, Gainesville, FL 32611, USA
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Matias Köhler
- Centro de Ciências Humanas e Biológicas, Departamento de Biologia, Universidade Federal de São Carlos (UFSCar), Sorocaba 18052-780, SP, Brazil
| | - Raul Puente
- Department of Research and Conservation, Desert Botanical Garden, Phoenix, AZ 85008, USA
| | - Wendy C Hodgson
- Department of Research and Conservation, Desert Botanical Garden, Phoenix, AZ 85008, USA
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Johnston MA, Waite ES, Wright ER, Reily BH, De Leon GJ, Esquivel AI, Kerwin J, Salazar M, Sarmiento E, Thiatmaja T, Lee S, Yule K, Franz N. Insect collecting bias in Arizona with a preliminary checklist of the beetles from the Sand Tank Mountains. Biodivers Data J 2023; 11:e101960. [PMID: 37427371 PMCID: PMC10323768 DOI: 10.3897/bdj.11.e101960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 05/15/2023] [Indexed: 07/11/2023] Open
Abstract
Background The State of Arizona in the south-western United States supports a high diversity of insects. Digitised occurrence records, especially from preserved specimens in natural history collections, are an important and growing resource to understand biodiversity and biogeography. Underlying bias in how insects are collected and what that means for interpreting patterns of insect diversity is largely untested. To explore the effects of insect collecting bias in Arizona, the State was regionalised into specific areas. First, the entire State was divided into broad biogeographic areas by ecoregion. Second, the 81 tallest mountain ranges were mapped on to the State. The distribution of digitised records across these areas were then examined.A case study of surveying the beetles (Insecta, Coleoptera) of the Sand Tank Mountains is presented. The Sand Tanks are a low-elevation range in the Lower Colorado River Basin subregion of the Sonoran Desert from which a single beetle record was published before this study. New information The number of occurrence records and collecting events are very unevenly distributed throughout Arizona and do not strongly correlate with the geographic size of areas. Species richness is estimated for regions in Arizona using rarefaction and extrapolation. Digitised records from the disproportionately highly collected areas in Arizona represent at best 70% the total insect diversity within them. We report a total of 141 species of Coleoptera from the Sand Tank Mountains, based on 914 digitised voucher specimens. These specimens add important new records for taxa that were previously unavailable in digitised data and highlight important biogeographic ranges.Possible underlying mechanisms causing bias are discussed and recommendations are made for future targeted collecting of under-sampled regions. Insect species diversity is apparently at best 70% documented for the State of Arizona with many thousands of species not yet recorded. The Chiricahua Mountains are the most densely sampled region of Arizona and likely contain at least 2,000 species not yet vouchered in online data. Preliminary estimates for species richness of Arizona are at least 21,000 and likely much higher. Limitations to analyses are discussed which highlight the strong need for more insect occurrence data.
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Affiliation(s)
- M. Andrew Johnston
- Biodiversity Knowledge Integration Center, Arizona State University, Tempe, AZ, United States of AmericaBiodiversity Knowledge Integration Center, Arizona State UniversityTempe, AZUnited States of America
| | - Evan S. Waite
- Biodiversity Knowledge Integration Center, Arizona State University, Tempe, AZ, United States of AmericaBiodiversity Knowledge Integration Center, Arizona State UniversityTempe, AZUnited States of America
| | - Ethan R Wright
- Biodiversity Knowledge Integration Center, Arizona State University, Tempe, AZ, United States of AmericaBiodiversity Knowledge Integration Center, Arizona State UniversityTempe, AZUnited States of America
| | - Brian H. Reily
- Biodiversity Knowledge Integration Center, Arizona State University, Tempe, AZ, United States of AmericaBiodiversity Knowledge Integration Center, Arizona State UniversityTempe, AZUnited States of America
| | - Gilma Juanita De Leon
- Biodiversity Knowledge Integration Center, Arizona State University, Tempe, AZ, United States of AmericaBiodiversity Knowledge Integration Center, Arizona State UniversityTempe, AZUnited States of America
| | - Angela Iran Esquivel
- Biodiversity Knowledge Integration Center, Arizona State University, Tempe, AZ, United States of AmericaBiodiversity Knowledge Integration Center, Arizona State UniversityTempe, AZUnited States of America
| | - Jacob Kerwin
- Biodiversity Knowledge Integration Center, Arizona State University, Tempe, AZ, United States of AmericaBiodiversity Knowledge Integration Center, Arizona State UniversityTempe, AZUnited States of America
| | - Maria Salazar
- Biodiversity Knowledge Integration Center, Arizona State University, Tempe, AZ, United States of AmericaBiodiversity Knowledge Integration Center, Arizona State UniversityTempe, AZUnited States of America
| | - Emiliano Sarmiento
- Biodiversity Knowledge Integration Center, Arizona State University, Tempe, AZ, United States of AmericaBiodiversity Knowledge Integration Center, Arizona State UniversityTempe, AZUnited States of America
| | - Tommy Thiatmaja
- Biodiversity Knowledge Integration Center, Arizona State University, Tempe, AZ, United States of AmericaBiodiversity Knowledge Integration Center, Arizona State UniversityTempe, AZUnited States of America
| | - Sangmi Lee
- Biodiversity Knowledge Integration Center, Arizona State University, Tempe, AZ, United States of AmericaBiodiversity Knowledge Integration Center, Arizona State UniversityTempe, AZUnited States of America
| | - Kelsey Yule
- Biodiversity Knowledge Integration Center, Arizona State University, Tempe, AZ, United States of AmericaBiodiversity Knowledge Integration Center, Arizona State UniversityTempe, AZUnited States of America
| | - Nico Franz
- Biodiversity Knowledge Integration Center, Arizona State University, Tempe, AZ, United States of AmericaBiodiversity Knowledge Integration Center, Arizona State UniversityTempe, AZUnited States of America
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Duarte MA, Woo S, Hultine K, Blonder B, Aparecido LMT. Vein network redundancy and mechanical resistance mitigate gas exchange losses under simulated herbivory in desert plants. AoB Plants 2023; 15:plad002. [PMID: 36959913 PMCID: PMC10029807 DOI: 10.1093/aobpla/plad002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 06/18/2023]
Abstract
Herbivory can impact gas exchange, but the causes of interspecific variation in response remain poorly understood. We aimed to determine (1) what effects does experimental herbivory damage to leaf midveins have on leaf gas exchange and, (2) whether changes in leaf gas exchange after damage was predicted by leaf mechanical or venation traits. We hypothesized that herbivory-driven impacts on leaf gas exchange would be mediated by (1a/1b) venation networks, either by more vein resistance, or possibly trading off with other structural defenses; (2a/2b) or more reticulation (resilience, providing more alternate flow pathways after damage) or less reticulation (sectoriality, preventing spread of reduced functionality after damage). We simulated herbivory by damaging the midveins of four leaves from each of nine Sonoran Desert species. We then measured the percent change in photosynthesis (ΔAn%), transpiration (ΔEt%) and stomatal conductance (Δgsw%) between treated and control leaves. We assessed the relationship of each with leaf venation traits and other mechanical traits. ΔAn% varied between +10 % and -55%, similar to ΔEt% (+27%, -54%) and Δgsw% (+36%, -53%). There was no tradeoff between venation and other structural defenses. Increased damage resilience (reduced ΔAn%, ΔEt%, Δgsw%) was marginally associated with lower force-to-tear (P < 0.05), and higher minor vein density (P < 0.10) but not major vein density or reticulation. Leaf venation networks may thus partially mitigate the response of gas exchange to herbivory and other types of vein damage through either resistance or resilience.
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Affiliation(s)
- Miguel A Duarte
- School of Life Sciences, Arizona State University, 427 E Tyler Mall, Tempe, AZ 85281, USA
| | - Sabrina Woo
- School of Life Sciences, Arizona State University, 427 E Tyler Mall, Tempe, AZ 85281, USA
| | - Kevin Hultine
- Department of Research, Conservation and Collections, Desert Botanical Garden, 1201 N. Galvin Parkway, Phoenix, AZ 85008, USA
| | - Benjamin Blonder
- School of Life Sciences, Arizona State University, 427 E Tyler Mall, Tempe, AZ 85281, USA
- Department of Environmental Science, Policy, and Management, University of California Berkeley, 120 Mulford Hall, Berkeley, CA 94720, USA
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Harrington S, Burbrink F. Complex cycles of divergence and migration shape lineage structure in the common kingsnake species complex. J Biogeogr 2023; 50:341-351. [PMID: 36817740 PMCID: PMC9937589 DOI: 10.1111/jbi.14536] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 10/17/2022] [Indexed: 06/18/2023]
Abstract
Aim The Nearctic is a complex patchwork of habitats and geologic features that form barriers to gene flow resulting in phylogeographic structure and speciation in many lineages. Habitats are rarely stable over geologic time, and the Nearctic has undergone major climatic changes in the past few million years. We use the common kingsnake species complex to study how climate, geography, and history influence lineage formation over a large, complex landscape. Location Nearctic/North America. Taxon Common kingsnake, Lampropeltis getula, species complex. Methods We analyzed genome-wide sequence data from 51 snakes spanning the majority of the species complex's range. We used population clustering, generalized dissimilarity modeling, and coalescent methods to identify the number of genetic clusters within the L. getula complex, infer the environmental correlates of genetic differentiation, and estimate models of divergence and gene flow among lineages. Results We identified three major lineages within the L. getula complex and further continuous spatial structure within lineages. The most important ecological correlates of genetic distance in the complex are related to aridity and precipitation, consistent with lineage breaks at the Great Plains/Desert ecotone and the Cochise Filter Barrier. Lineages are estimated to have undergone multiple rounds of isolation and secondary contact, with highly asymmetric migration occurring at present. Main conclusions Changing climates combined with a large and geologically complex landscape have resulted in a mosaic of discrete and spatially continuous genetic structure. Multiple rounds of isolation and secondary contact as climate fluctuated over the past ~4.4 My have likely driven the evolution of discrete lineages that maintain high levels of gene flow. Continuous structure is strongly shaped by aridity and precipitation, suggesting roles for major precipitation gradients in helping to maintain lineage identity in the face of gene flow when lineages are in geographic contact.
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Affiliation(s)
- Sean Harrington
- Department of Herpetology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA
- INBRE Data Science Core, University of Wyoming, Laramie, WY 82071, USA
| | - Frank Burbrink
- Department of Herpetology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA
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Breslin PB, Wojciechowski MF, Majure LC. Remarkably rapid, recent diversification of Cochemiea and Mammillaria in the Baja California, Mexico region. Am J Bot 2022; 109:1472-1487. [PMID: 35979551 PMCID: PMC9826077 DOI: 10.1002/ajb2.16048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 08/02/2022] [Accepted: 08/03/2022] [Indexed: 06/15/2023]
Abstract
PREMISE The Cactaceae of northwestern Mexico and the southwestern United States constitute a major component of the angiosperm biodiversity of the region. The Mammilloid clade, (Cactaceae, tribe Cacteae), composed of the genera Cochemiea, Coryphantha, Cumarinia, Mammillaria, and Pelecyphora is especially species rich. We sought to understand the timing, geographical and climate influences correlated with expansion of the Mammilloid clade, through the Sonoran Desert into Baja California. METHODS We reconstructed the historical biogeography of the Mammilloid clade, using Bayesian and maximum likelihood methods, based on a strongly supported molecular phylogeny. We also estimated divergence times, the timing of emergence of key characters, and diversification rates and rate shifts of the Mammilloid clade. RESULTS We found that the most recent common ancestor of Cochemiea arrived in the Cape region of Baja California from the Sonoran Desert region approximately 5 million years ago, coinciding with the timing of peninsular rifting from the mainland, suggesting dispersal and vicariance as causes of species richness and endemism. The diversification rate for Cochemiea is estimated to be approximately 12 times that of the mean background diversification rate for angiosperms. Divergence time estimation shows that many of the extant taxa in Cochemiea and Baja California Mammillaria emerged from common ancestors 1 million to 200,000 years ago, having a mid-Pleistocene origin. CONCLUSIONS Cochemiea and Mammillaria of the Baja California region are examples of recent, rapid diversification. Geological and climatic forces at multiple spatial and temporal scales are correlated with the western distributions of the Mammilloid clade.
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Affiliation(s)
- Peter B. Breslin
- Arizona State UniversitySchool of Life Sciences427 East Tyler MallTempeArizona85287USA
| | | | - Lucas C. Majure
- University of Florida HerbariumFlorida Museum of Natural History379 Dickinson Hall, 1659 Museum Rd.GainesvilleFlorida32611USA
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Jiménez-Leyva A, Orozco-Avitia J, Gutiérrez A, Vargas G, Sánchez E, Muñoz E, Esqueda M. Functional plasticity of Capsicum annuum var. glabriusculum through multiple traits. AoB Plants 2022; 14:plac017. [PMID: 35774379 PMCID: PMC9237842 DOI: 10.1093/aobpla/plac017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 05/04/2022] [Indexed: 06/15/2023]
Abstract
The diversity of functional traits still has not been studied enough in model plant species, even less so in little-known species. This experiment was carried out under the extreme heat of Sonoran Desert, using shading nets and under conditions where the availability of water and nutrients was not a stress factor. We evaluated how the low, intermediate and high sunlight regimes impact survival and promote multiple alterations on phenological and ecophysiological response of cultivated Capsicum annuum var. glabriusculum plants. Extremely warm temperatures promoted a high heat sum in degrees days throughout plants development. Most plants grown in high sunlight regimes did not survive; under intermediate sunlight regimes survival was high and plants developed vegetative and reproductively; but under low sunlight regimes plants survival was high; however, they developed just vegetatively. Photosynthetic response to light suggests that plants are physiologically acclimated to low and intermediate irradiance, whereas the CO2 assimilation curves suggest contrasting photosynthetic capacity traits. Under the intermediate sunlight regimes, plants strengthened their performance through multiple functional traits (e.g. CO2 and water diffusion traits, photosynthetic capacity, respiration, among others). Consequently, their biomass gain was faster and proportionally higher by 76 % with an investment of 14 % in fruits development. The principal components analysis extracted the main explanatory functional traits: photosynthetic nitrogen allocation, stomatal limitation, mesophyll conductance, Rubisco maximum carboxylation velocity, among others. In conclusion, phenological response and multiple functional traits determine plants acclimation to sunlight regimes and extremely warm temperatures in short term.
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Affiliation(s)
- Alberto Jiménez-Leyva
- Centro de Investigación en Alimentación y Desarrollo, Carretera Gustavo Enrique Astiazarán Rosas No. 46, Col. La Victoria, Hermosillo, Sonora C.P. 83304, México
| | - Jesús Orozco-Avitia
- Centro de Investigación en Alimentación y Desarrollo, Carretera Gustavo Enrique Astiazarán Rosas No. 46, Col. La Victoria, Hermosillo, Sonora C.P. 83304, México
| | - Aldo Gutiérrez
- Centro de Investigación en Alimentación y Desarrollo, Carretera Gustavo Enrique Astiazarán Rosas No. 46, Col. La Victoria, Hermosillo, Sonora C.P. 83304, México
| | - Georgina Vargas
- Centro de Investigación en Alimentación y Desarrollo, Carretera Gustavo Enrique Astiazarán Rosas No. 46, Col. La Victoria, Hermosillo, Sonora C.P. 83304, México
| | - Esteban Sánchez
- Centro de Investigación en Alimentación y Desarrollo, Av. 4ta Sur 3820, Fracc. Vencedores del Desierto, Delicias, Chihuahua C.P. 33089, México
| | - Ezequiel Muñoz
- Centro de Investigación en Alimentación y Desarrollo, Av. 4ta Sur 3820, Fracc. Vencedores del Desierto, Delicias, Chihuahua C.P. 33089, México
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Nabhan GP, Daugherty E, Hartung T. Health Benefits of the Diverse Volatile Oils in Native Plants of Ancient Ironwood-Giant Cactus Forests of the Sonoran Desert: An Adaptation to Climate Change? Int J Environ Res Public Health 2022; 19:ijerph19063250. [PMID: 35328938 PMCID: PMC8950382 DOI: 10.3390/ijerph19063250] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/01/2022] [Accepted: 03/05/2022] [Indexed: 11/16/2022]
Abstract
We document the species richness and volatile oil diversity in Sonoran Desert plants found in the Arizona Uplands subdivision of this binational USA/Mexico region. Using floristics, we determined that more than 60 species of 178 native plants in the ancient ironwood-giant cactus forests emit fragrant biogenic volatile organic compounds (BVOCs), especially with the onset of summer monsoons. From these desert species, more than 115 volatile oils have been identified from one biogeographic region. For the 5 BVOCs most commonly associated with “forest bathing” practices in Asian temperate forests, at least 15 Sonoran Desert plant species emit them in Arizona Uplands vegetation. We document the potential health benefits attributed to each of 13 BVOCs in isolation, but we also hypothesize that the entire “suite” of BVOCs emitted from a diversity of desert plants during the monsoons may function synergistically to generate additional health benefits. Regular exposure to these BVOC health benefits may become more important to prevent or mitigate diseases of oxidative stress and other climate maladies in a hotter, drier world.
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Affiliation(s)
- Gary Paul Nabhan
- Southwest Center, University of Arizona, Tucson, AZ 85721, USA;
- Correspondence:
| | - Eric Daugherty
- Southwest Center, University of Arizona, Tucson, AZ 85721, USA;
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Sanderson MJ, Búrquez A, Copetti D, McMahon MM, Zeng Y, Wojciechowski MF. Origin and diversification of the saguaro cactus (Carnegiea gigantea): a within-species phylogenomic analysis. Syst Biol 2022; 71:1178-1194. [PMID: 35244183 DOI: 10.1093/sysbio/syac017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 02/18/2022] [Accepted: 02/25/2022] [Indexed: 11/14/2022] Open
Abstract
Reconstructing accurate historical relationships within a species poses numerous challenges, not least in many plant groups in which gene flow is high enough to extend well beyond species boundaries. Nonetheless, the extent of tree-like history within a species is an empirical question on which it is now possible to bring large amounts of genome sequence to bear. We assess phylogenetic structure across the geographic range of the saguaro cactus, an emblematic member of Cactaceae, a clade known for extensive hybridization and porous species boundaries. Using 200 Gb of whole genome resequencing data from 20 individuals sampled from 10 localities, we assembled two data sets comprising 150,000 biallelic single nucleotide polymorphisms (SNPs) from protein coding sequences. From these we inferred within-species trees and evaluated their significance and robustness using five qualitatively different inference methods. Despite the low sequence diversity, large census population sizes, and presence of wide-ranging pollen and seed dispersal agents, phylogenetic trees were well resolved and highly consistent across both data sets and all methods. We inferred that the most likely root, based on marginal likelihood comparisons, is to the east and south of the region of highest genetic diversity, which lies along the coast of the Gulf of California in Sonora, Mexico. Together with striking decreases in marginal likelihood found to the north, this supports hypotheses that saguaro's current range reflects post-glacial expansion from the refugia in the south of its range. We conclude with observations about practical and theoretical issues raised by phylogenomic data sets within species, in which SNP-based methods must be used rather than gene tree methods that are widely used when sequence divergence is higher. These include computational scalability, inference of gene flow, and proper assessment of statistical support in the presence of linkage effects.
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Affiliation(s)
- Michael J Sanderson
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA
| | - Alberto Búrquez
- Instituto de Ecología, Unidad Hermosillo, Universidad Nacional Autónoma de México, Hermosillo, Sonora, Mexico
| | - Dario Copetti
- Arizona Genomics Institute, School of Plant Sciences, University of Arizona, Tucson, AZ, 85721 USA
| | | | - Yichao Zeng
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA
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Aslan CE, Sandor M, Sample M, Stortz S, Souther S, Levine C, Samberg L, Gray M, Dickson B. Estimating social-ecological resilience: fire management futures in the Sonoran Desert. Ecol Appl 2021; 31:e02303. [PMID: 33577093 DOI: 10.1002/eap.2303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 08/27/2020] [Accepted: 10/06/2020] [Indexed: 06/12/2023]
Abstract
Resilience quantifies the ability of a system to remain in or return to its current state following disturbance. Due to inconsistent terminology and usage of resilience frameworks, quantitative resilience studies are challenging, and resilience is often treated as an abstract concept rather than a measurable system characteristic. We used a novel, spatially explicit stakeholder engagement process to quantify social-ecological resilience to fire, in light of modeled social-ecological fire risk, across the non-fire-adapted Sonoran Desert Ecosystem in Arizona, USA. Depending on its severity and the characteristics of the ecosystem, fire as a disturbance has the potential to drive ecological state change. As a result, fire regime change is of increasing concern as global change and management legacies alter the distribution and flammability of fuels. Because management and use decisions impact resources and ecological processes, social and ecological factors must be evaluated together to predict resilience to fire. We found highest fire risk in the central and eastern portions of the study area, where flammable fuels occur with greater density and frequency and managers reported fewer management resources than in other locations. We found lowest fire resilience in the southeastern portion of the study area, where combined ecological and social factors, including abundant fuels, few management resources, and little evidence of past institutional adaptability, indicated that sites were least likely to retain their current characteristics and permit achievement of current management objectives. Analyzing ecological and social characteristics together permits regional managers to predict the effects of changing fire regimes across large, multi-jurisdictional landscapes and to consider where to direct resources. This study brought social and ecological factors together into a common spatial framework to produce vulnerability maps; our methods may inform researchers and managers in other systems facing novel disturbance and spatially variable resilience.
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Affiliation(s)
- Clare E Aslan
- Landscape Conservation Initiative, Northern Arizona University, Box 5694, Flagstaff, Arizona, 86011, USA
- Conservation Science Partners, 11050 Pioneer Trail, Suite 202, Truckee, California, 96161, USA
| | - Manette Sandor
- Landscape Conservation Initiative, Northern Arizona University, Box 5694, Flagstaff, Arizona, 86011, USA
| | - Martha Sample
- Landscape Conservation Initiative, Northern Arizona University, Box 5694, Flagstaff, Arizona, 86011, USA
| | - Sasha Stortz
- Landscape Conservation Initiative, Northern Arizona University, Box 5694, Flagstaff, Arizona, 86011, USA
| | - Sara Souther
- Landscape Conservation Initiative, Northern Arizona University, Box 5694, Flagstaff, Arizona, 86011, USA
| | - Carrie Levine
- Conservation Science Partners, 11050 Pioneer Trail, Suite 202, Truckee, California, 96161, USA
| | - Leah Samberg
- Conservation Science Partners, 11050 Pioneer Trail, Suite 202, Truckee, California, 96161, USA
| | - Miranda Gray
- Conservation Science Partners, 11050 Pioneer Trail, Suite 202, Truckee, California, 96161, USA
| | - Brett Dickson
- Landscape Conservation Initiative, Northern Arizona University, Box 5694, Flagstaff, Arizona, 86011, USA
- Conservation Science Partners, 11050 Pioneer Trail, Suite 202, Truckee, California, 96161, USA
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11
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Johnson RA. Desiccation limits recruitment in the pleometrotic desert seed-harvester ant Veromessor pergandei. Ecol Evol 2021; 11:294-308. [PMID: 33437430 PMCID: PMC7790620 DOI: 10.1002/ece3.7039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 10/07/2020] [Accepted: 10/21/2020] [Indexed: 11/14/2022] Open
Abstract
The desert harvester ant Veromessor pergandei displays geographic variation in colony founding with queens initiating nests singly (haplometrosis) or in groups (pleometrosis). The transition from haplo- to pleometrotic founding is associated with lower rainfall. Numerous hypotheses have been proposed to explain the evolution of cooperative founding in this species, but the ultimate explanation remains unanswered. In laboratory experiments, water level was positively associated with survival, condition, and brood production by single queens. Queen survival also was positively influenced by water level and queen number in a two-factor experiment. Water level also was a significant effect for three measures of queen condition, but queen number was not significant for any measure. Foundress queens excavated after two weeks of desiccating conditions were dehydrated compared to alate queens captured from their natal colony, indicating that desiccation can be a source of queen mortality. Long-term monitoring in central Arizona, USA, documented that recruitment only occurred in four of 20 years. A discriminant analysis using rainfall as a predictor of recruitment correctly predicted recruitment in 17 of 20 years for total rainfall from January to June (the period for mating flights and establishment) and in 19 of 20 years for early plus late rainfall (January-March and April-June, respectively), often with a posterior probability > 0.90. Moreover, recruitment occurred only in years in which both early and late rainfall exceeded the long-term mean. This result also was supported by the discriminant analysis predicting no recruitment when long-term mean early and late rainfall were included as ungrouped periods. These data suggest that pleometrosis in V. pergandei evolved to enhance colony survival in areas with harsh abiotic (desiccating) conditions, facilitating colonization of habitats in which solitary queens could not establish even in wet years. This favorable-year hypothesis supports enhanced worker production as the primary advantage of pleometrosis.
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12
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Marx HE, Scheidt S, Barker MS, Dlugosch KM. TagSeq for gene expression in non-model plants: A pilot study at the Santa Rita Experimental Range NEON core site. Appl Plant Sci 2020; 8:e11398. [PMID: 33304661 PMCID: PMC7705334 DOI: 10.1002/aps3.11398] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 08/20/2020] [Indexed: 05/12/2023]
Abstract
PREMISE TagSeq is a cost-effective approach for gene expression studies requiring a large number of samples. To date, TagSeq studies in plants have been limited to those with a high-quality reference genome. We tested the suitability of reference transcriptomes for TagSeq in non-model plants, as part of a study of natural gene expression variation at the Santa Rita Experimental Range National Ecological Observatory Network (NEON) core site. METHODS Tissue for TagSeq was sampled from multiple individuals of four species (Bouteloua aristidoides and Eragrostis lehmanniana [Poaceae], Tidestromia lanuginosa [Amaranthaceae], and Parkinsonia florida [Fabaceae]) at two locations on three dates (56 samples total). One sample per species was used to create a reference transcriptome via standard RNA-seq. TagSeq performance was assessed by recovery of reference loci, specificity of tag alignments, and variation among samples. RESULTS A high fraction of tags aligned to each reference and mapped uniquely. Expression patterns were quantifiable for tens of thousands of loci, which revealed consistent spatial differentiation in expression for all species. DISCUSSION TagSeq using de novo reference transcriptomes was an effective approach to quantifying gene expression in this study. Tags were highly locus specific and generated biologically informative profiles for four non-model plant species.
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Affiliation(s)
- Hannah E. Marx
- Department of Ecology and Evolutionary BiologyUniversity of ArizonaTucsonArizona85721USA
- Department of Ecology and Evolutionary BiologyUniversity of MichiganAnn ArborMichigan48109‐1048USA
| | - Stephen Scheidt
- Howard University2400 6th Street NWWashingtonD.C.20059USA
- Solar System Exploration DivisionNASA Goddard Space Flight CenterGreenbeltMaryland20771USA
- Center for Research and Exploration in Space Science and TechnologyNASA Goddard Space Flight CenterGreenbeltMaryland20771USA
| | - Michael S. Barker
- Department of Ecology and Evolutionary BiologyUniversity of ArizonaTucsonArizona85721USA
| | - Katrina M. Dlugosch
- Department of Ecology and Evolutionary BiologyUniversity of ArizonaTucsonArizona85721USA
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13
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Payne N, Kraberger S, Fontenele RS, Schmidlin K, Bergeman MH, Cassaigne I, Culver M, Varsani A, Van Doorslaer K. Novel Circoviruses Detected in Feces of Sonoran Felids. Viruses 2020; 12:v12091027. [PMID: 32942563 PMCID: PMC7551060 DOI: 10.3390/v12091027] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 09/08/2020] [Accepted: 09/10/2020] [Indexed: 01/22/2023] Open
Abstract
Sonoran felids are threatened by drought and habitat fragmentation. Vector range expansion and anthropogenic factors such as habitat encroachment and climate change are altering viral evolutionary dynamics and exposure. However, little is known about the diversity of viruses present in these populations. Small felid populations with lower genetic diversity are likely to be most threatened with extinction by emerging diseases, as with other selective pressures, due to having less adaptive potential. We used a metagenomic approach to identify novel circoviruses, which may have a negative impact on the population viability, from confirmed bobcat (Lynx rufus) and puma (Puma concolor) scats collected in Sonora, Mexico. Given some circoviruses are known to cause disease in their hosts, such as porcine and avian circoviruses, we took a non-invasive approach using scat to identify circoviruses in free-roaming bobcats and puma. Three circovirus genomes were determined, and, based on the current species demarcation, they represent two novel species. Phylogenetic analyses reveal that one circovirus species is more closely related to rodent associated circoviruses and the other to bat associated circoviruses, sharing highest genome-wide pairwise identity of approximately 70% and 63%, respectively. At this time, it is unknown whether these scat-derived circoviruses infect felids, their prey, or another organism that might have had contact with the scat in the environment. Further studies should be conducted to elucidate the host of these viruses and assess health impacts in felids.
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Affiliation(s)
- Natalie Payne
- Genetics Graduate Interdisciplinary Program, University of Arizona, Tucson, AZ 85719, USA;
| | - Simona Kraberger
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ 85287-5001, USA; (S.K.); (R.S.F.); (K.S.)
| | - Rafaela S Fontenele
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ 85287-5001, USA; (S.K.); (R.S.F.); (K.S.)
| | - Kara Schmidlin
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ 85287-5001, USA; (S.K.); (R.S.F.); (K.S.)
| | - Melissa H Bergeman
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85721, USA;
| | | | - Melanie Culver
- Genetics Graduate Interdisciplinary Program, University of Arizona, Tucson, AZ 85719, USA;
- U.S. Geological Survey, Arizona Cooperative Fish and Wildlife Research Unit, University of Arizona, Tucson, AZ 85721, USA;
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ 85721, USA
| | - Arvind Varsani
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ 85287-5001, USA; (S.K.); (R.S.F.); (K.S.)
- Structural Biology Research Unit, Department of Integrative Biomedical Sciences, University of Cape Town, Observatory, Cape Town 7701, South Africa
- Correspondence: (A.V.); (K.V.D.)
| | - Koenraad Van Doorslaer
- Genetics Graduate Interdisciplinary Program, University of Arizona, Tucson, AZ 85719, USA;
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85721, USA;
- The BIO5 Institute, Department of Immunobiology, Cancer Biology Graduate Interdisciplinary Program, UA Cancer Center, University of Arizona Tucson, Tucson, AZ 85724, USA
- Correspondence: (A.V.); (K.V.D.)
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14
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Saul-Gershenz L, Grodsky SM, Hernandez RR. Ecology of the Western Queen Butterfly Danaus gilippus thersippus (Lepidoptera: Nymphalidae) in the Mojave and Sonoran Deserts. Insects 2020; 11:insects11050315. [PMID: 32438741 PMCID: PMC7290759 DOI: 10.3390/insects11050315] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 01/09/2023]
Abstract
The purpose of this study was to assess the ecological knowledge surrounding the western queen butterfly, Danaus gilippus thersippus (H. Bates). Specifically, our objectives were to synthesize existing data and knowledge on the ecology of the queen and use results of this assessment to inform the direction of future research on this understudied species. We identified six core areas for assessment: distribution, the biodiversity of plant resources, western queen and their host plant phenology, chemical ecology, and four key life history traits. We mapped the distribution of D. g. thersippus from museum specimen records, citizen science (e.g., iNaturalist) and image sharing app-based observations, along with other observational data enumerating all current known plant resources and long-range movements. We assembled 14 larval food plants, six pyrrolizidine alkaloids plants and six nectar plants distributed in the western Mojave and Sonoran Desert regions of the United States and Baja California. We report on its phenology and its long-range movement. Butterfly species have declined across the western US, and western monarch populations have declined by 97%. Danaus g. thersippus has received little research attention compared with its famous congener D. plexippus L. Danaus g. thersippus' desert distribution may be at its temperature limits for the species distribution and for its rare host plant Asclepias nyctaginifolia.
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Affiliation(s)
- Leslie Saul-Gershenz
- Wild Energy Initiative, John Muir Institute of the Environment, University of California, Davis, 1 Shields Ave., Davis, CA 95616, USA; (S.M.G.); (R.R.H.)
- Department of Entomology and Nematology, 1 Shields Ave., University of California, Davis, Davis, CA 95616, USA
- USDA-ARS, Invasive Species and Pollinator Health Research Unit, 3026 Bee Biology Rd, Davis, CA 95616, USA
- Correspondence:
| | - Steven M. Grodsky
- Wild Energy Initiative, John Muir Institute of the Environment, University of California, Davis, 1 Shields Ave., Davis, CA 95616, USA; (S.M.G.); (R.R.H.)
| | - Rebecca R. Hernandez
- Wild Energy Initiative, John Muir Institute of the Environment, University of California, Davis, 1 Shields Ave., Davis, CA 95616, USA; (S.M.G.); (R.R.H.)
- Department of Land, Air, and Water Resources, 1 Shields Ave., University of California, Davis, Davis, CA 95616, USA
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15
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Conway KW, Mateos M, Vrijenhoek RC. A new species of the live-bearing fish genus Poeciliopsis from northern Mexico (Cyprinodontiformes, Poeciliidae). Zookeys 2019; 883:91-118. [PMID: 31719775 PMCID: PMC6828827 DOI: 10.3897/zookeys.883.37586] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 09/19/2019] [Indexed: 11/12/2022] Open
Abstract
Poeciliopsisjackschultzisp. nov., is described based on seven specimens (17.9–26.7 mm SL) from the Río Concepción (also known as Río Magdalena), Sonora, Mexico. The new species belongs to the Leptorhaphis species group and can be distinguished from other members of this group by features of the skeleton and colouration. The new species is sympatric with P.occidentalis, a hybridogenetic all-female biotype P.monacha-occidentalis, and hybrids between P.monacha-occidentalis females and P.jackschultzi males. The distribution of P.jackschultzi is highly restricted, and the main habitat, spring-fed marshy streams and pools, is susceptible to loss and degradation in a desert environment with increasing human water demand.
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Affiliation(s)
- Kevin W Conway
- Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA.,Biodiversity Research and Teaching Collections, Texas A&M University, College Station, TX 77843, USA
| | - Mariana Mateos
- Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Robert C Vrijenhoek
- Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95039, USA
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16
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Félix-Burruel RE, Larios E, Bustamante E, Búrquez A. Nonlinear modeling of saguaro growth rates reveals the importance of temperature for size-dependent growth. Am J Bot 2019; 106:1300-1307. [PMID: 31529806 DOI: 10.1002/ajb2.1358] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 07/25/2019] [Indexed: 06/10/2023]
Abstract
PREMISE The saguaro cactus is an iconic species of the Sonoran Desert. Its individual growth rates have been investigated for over 100 years. Its growth dynamics have been studied using phenomenological models intended to estimate growth, but not to understand the underlying biological processes. Most studies have suggested summer rainfall as the sole factor determining saguaro growth, overlooking the influence of other factors related to the process of growth. METHODS We analyzed the annual growth rates for 13 saguaro populations in the Sonoran Desert using nonlinear models. These are better suited to analyze growth since they consider the fact that maximum growth rates diminish just before the onset of reproduction. We related model parameters to the local climate. RESULTS The most parsimonious model was the Ricker function that described growth considering cactus decline with age. Variance in temperature, rather than precipitation, was more closely related to growth. Higher variance in temperature at the beginning of the warm season was detrimental to saguaro growth. CONCLUSIONS Simple nonlinear equations modeled growth rate using biologically interpretable parameters related to climate factors. Because the temperature is projected to increase in both mean and variance by climate change, the population dynamics of this iconic cactus are likely to be affected.
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Affiliation(s)
- Ricardo E Félix-Burruel
- Posgrado en Ciencias de la Tierra, Instituto de Geología, Universidad Nacional Autónoma de México, México
- Instituto de Ecología, Universidad Nacional Autónoma de México, Hermosillo, Sonora, México
| | - Eugenio Larios
- Instituto de Ecología, Universidad Nacional Autónoma de México, Hermosillo, Sonora, México
| | - Enriquena Bustamante
- Instituto de Ecología, Universidad Nacional Autónoma de México, Hermosillo, Sonora, México
| | - Alberto Búrquez
- Instituto de Ecología, Universidad Nacional Autónoma de México, Hermosillo, Sonora, México
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17
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Tomasek BJ, Burghardt LT, Shriver RK. Filling in the gaps in survival analysis: using field data to infer plant responses to environmental stressors. Ecology 2019; 100:e02778. [PMID: 31168840 DOI: 10.1002/ecy.2778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 01/28/2019] [Accepted: 04/26/2019] [Indexed: 11/11/2022]
Abstract
Elucidating how organismal survival depends on the environment is a core component of ecological and evolutionary research. To reconcile high-frequency covariates with lower-frequency demographic censuses, many statistical tools involve aggregating environmental conditions over long periods, potentially obscuring the importance of fluctuating conditions in driving mortality. Here, we introduce a flexible model designed to infer how survival probabilities depend on changing environmental covariates. Specifically, the model (1) quantifies effects of environmental covariates at a higher frequency than the census intervals, and (2) allows partitioning of environmental drivers of individual survival into acute (short-term) and chronic (accumulated) effects. By applying our method to a long-term observational data set of eight annual plant species, we show we can accurately infer daily survival probabilities as temperature and moisture levels change. Next, we show that a species' water use efficiency, known to mediate annual plant population dynamics, is positively correlated with the importance of "chronic stress" inferred by the model. This suggests that model parameters can reflect underlying physiological mechanisms. This method is also applicable to other binary responses (hatching, phenology) or systems (insects, nestlings). Once known, environmental sensitivities can be used for ecological forecasting even when the frequency or variability of environments are changing.
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Affiliation(s)
- Bradley J Tomasek
- Program in Ecology, Biological Sciences Building, 130 Science Drive, Duke University, Durham, North Carolina, USA.,Nicholas School of the Environment, Duke University, Durham, North Carolina, 27708, USA.,2000 W. Lincoln St. Mount Prospect, IL 60056
| | - Liana T Burghardt
- Department of Biology, Biological Sciences Building, 130 Science Drive, Duke University, Durham, North Carolina, USA.,Department of Plant and Microbial Biology, University of Minnesota, 1479 Gortner Avenue, St. Paul, Minnesota, 55108, USA
| | - Robert K Shriver
- Program in Ecology, Biological Sciences Building, 130 Science Drive, Duke University, Durham, North Carolina, USA.,Department of Biology, Biological Sciences Building, 130 Science Drive, Duke University, Durham, North Carolina, USA
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18
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Ornelas JF, García JM, Ortiz-Rodriguez AE, Licona-Vera Y, Gándara E, Molina-Freaner F, Vásquez-Aguilar AA. Tracking Host Trees: The Phylogeography of Endemic Psittacanthus sonorae (Loranthaceae) Mistletoe in the Sonoran Desert. J Hered 2019; 110:229-246. [PMID: 30496534 DOI: 10.1093/jhered/esy065] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 11/26/2018] [Indexed: 01/29/2023] Open
Abstract
The host dependence of mistletoes suggests that they track the distributions of their hosts. However, the factors that determine the geographic distribution of mistletoes are not well understood. In this study, the phylogeography of Psittacanthus sonorae was reconstructed by sequencing one nuclear (ITS) and two plastid (trnL-F and atpB-rbcL) regions of 148 plants from populations separated by the Sea of Cortez. Divergence time and gene flow were estimated to gain insight into the historical demography and geographic structuring of genetic variation. We also described and mapped the spatial distribution of suitable habitat occupied by P. sonorae and its most common host Bursera microphylla in the Sonoran Desert, along with their responses to Quaternary climate fluctuations using environmental data and ecological niche modeling (ENM). We detected environmental and genetic differentiation between the peninsular and continental P. sonorae populations. Population divergence occurred during the Pleistocene, around the time of the Last Glacial Maximum. No signals of population growth were detected, with net gene flow moving from the continent to the peninsula. ENM models indicate decoupled responses by the mistletoe and its main host to past climate changes. For the Last Interglacial to the present, most models produce only partial areas of overlap on both the peninsula and the continent. Our results support a scenario of Late-Pleistocene isolation and divergence with asymmetrical gene flow between peninsular and continental P. sonorae populations. Continental populations migrated to the peninsula and the spatial isolation probably produced genetic differentiation under different environmental conditions.
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Affiliation(s)
- Juan Francisco Ornelas
- Departamento de Biología Evolutiva, Instituto de Ecología, A.C. (INECOL), Carretera antigua a Coatepec, El Haya, Xalapa, Veracruz, Mexico
| | - José Manuel García
- Departamento de Biología Evolutiva, Instituto de Ecología, A.C. (INECOL), Carretera antigua a Coatepec, El Haya, Xalapa, Veracruz, Mexico
| | - Andrés E Ortiz-Rodriguez
- Departamento de Biología Evolutiva, Instituto de Ecología, A.C. (INECOL), Carretera antigua a Coatepec, El Haya, Xalapa, Veracruz, Mexico.,Instituto de Investigaciones Forestales, Universidad Veracruzana, Xalapa, Veracruz, Mexico
| | - Yuyini Licona-Vera
- Departamento de Biología Evolutiva, Instituto de Ecología, A.C. (INECOL), Carretera antigua a Coatepec, El Haya, Xalapa, Veracruz, Mexico
| | - Etelvina Gándara
- Departamento de Biología Evolutiva, Instituto de Ecología, A.C. (INECOL), Carretera antigua a Coatepec, El Haya, Xalapa, Veracruz, Mexico.,Facultad de Ciencias Biológicas, Benemérita Universidad Autónoma de Puebla, Puebla, Puebla, Mexico
| | - Francisco Molina-Freaner
- Instituto de Ecología e Instituto de Geología, Universidad Nacional Autónoma de México (UNAM), Estación Regional del Noroeste, Hermosillo, Sonora, Mexico
| | - Antonio Acini Vásquez-Aguilar
- Departamento de Biología Evolutiva, Instituto de Ecología, A.C. (INECOL), Carretera antigua a Coatepec, El Haya, Xalapa, Veracruz, Mexico
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Ii KM, Kono N, Paulino-Lima IG, Tomita M, Rothschild LJ, Arakawa K. Complete Genome Sequence of Arthrobacter sp. Strain MN05-02, a UV-Resistant Bacterium from a Manganese Deposit in the Sonoran Desert. J Genomics 2019; 7:18-25. [PMID: 30820258 PMCID: PMC6389495 DOI: 10.7150/jgen.32194] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 01/08/2019] [Indexed: 12/26/2022] Open
Abstract
Arthrobacter sp. strain MN05-02 is a UV-resistant bacterium isolated from a manganese deposit in the Sonoran Desert, Arizona, USA. The LD10 of this strain is 123 Jm-2, which is twice that of Escherichia coli, and therefore can be a useful resource for comparative study of UV resistance and the role of manganese on this phenotype. Its complete genome is comprised of a chromosome of 3,488,433 bp and a plasmid of 154,991 bp. The chromosome contains 3,430 putative genes, including 3,366 protein coding genes, 52 tRNA and 12 rRNA genes. Carotenoid biosynthesis operon structure coded within the genome mirrors the characteristic orange-red pigment this bacterium produces, which presumably partly contribute to its UV resistance.
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Affiliation(s)
- Konosuke Mark Ii
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0052, Japan.,Faculty of Environment and Information Studies, Keio University, Yamagata, 997-0052, Japan
| | - Nobuaki Kono
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0052, Japan.,Graduate School of Media and Governance, Keio University, Yamagata, 997-0052, Japan
| | - Ivan Glaucio Paulino-Lima
- Blue Marble Space Institute of Science at NASA Ames Research Center, Mountain View, CA, USA, 94035-0001
| | - Masaru Tomita
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0052, Japan.,Faculty of Environment and Information Studies, Keio University, Yamagata, 997-0052, Japan.,Graduate School of Media and Governance, Keio University, Yamagata, 997-0052, Japan
| | | | - Kazuharu Arakawa
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0052, Japan.,Faculty of Environment and Information Studies, Keio University, Yamagata, 997-0052, Japan.,Graduate School of Media and Governance, Keio University, Yamagata, 997-0052, Japan
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20
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Day TA, Bliss MS, Tomes AR, Ruhland CT, Guénon R. Desert leaf litter decay: Coupling of microbial respiration, water-soluble fractions and photodegradation. Glob Chang Biol 2018; 24:5454-5470. [PMID: 30194795 DOI: 10.1111/gcb.14438] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 08/10/2018] [Accepted: 08/28/2018] [Indexed: 06/08/2023]
Abstract
The mechanisms of plant litter decay in drylands are poorly understood, limiting the accuracy of nutrient-cycling models for these systems. We monitored the decay of 12 leaf litter types on the soil surface of the Sonoran Desert for 34 months and assessed what traits predicted mass loss and how exposure to different wavebands of sunlight influenced mass loss. Mass loss varied considerably among litter types, ranging from 42%-96% after 34 months in full sunlight. Traditional indices of litter quality (e.g., initial C:N or lignin:N ratios) failed to predict differences in mass loss among litter types. The strongest predictor of mass loss was the microbial respiration rate of initial litter, which explained 45%-54% of the variation in loss among litter types. Microbial respiration rates were not correlated with traditional indices of litter quality, but were positively correlated with the water-soluble fraction in litter and concentrations of dissolved organic C in this fraction. Traditional indices of litter quality failed to predict decay likely because they did a poor job of predicting microbial degradability of litter, not because microbial degradation was a minor driver of decay. In all radiation-exposure treatments, water-soluble fractions and respiration rates increased through decay and were several times higher after 34 months than initially. Hence, labile pools and microbial degradability of litter increased through decay in contrast to traditional views that labile pools decline and constrain microbes. Litter exposed to UV or UV through blue radiation wavelengths, lost on average 1.3 times or 1.5 times more mass, respectively, than litter not exposed to these wavebands. The magnitude of this photodegradation was greater in litter types that had higher initial concentrations of hemicellulose and cellulose per unit surface area. Litter exposed to full sun had higher water-soluble fractions and usually had higher respiration rates, illustrating that sunlight accelerated microbial degradation by increasing labile pools. The processes driving litter decay appeared to differ appreciably from mesic systems and involved strong couplings between abiotic and biotic drivers.
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Affiliation(s)
- Thomas A Day
- School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Michael S Bliss
- School of Life Sciences, Arizona State University, Tempe, Arizona
| | | | - Christopher T Ruhland
- Department of Biological Sciences, TS-242 Trafton Sciences Center, Minnesota State University, Mankato, Minnesota
| | - René Guénon
- School of Life Sciences, Arizona State University, Tempe, Arizona
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Abstract
Euchaetesnancyaesp. n. is described from southeastern Arizona. Although superficially similar to species of Pygarctia Grote, structural and molecular variation shows it to be most closely related to Euchaeteshelena (Cassino). Adults, genitalic structure, eggs, and first instar larvae are described and illustrated. The larval host plant remains unknown. Euchaeteshelena is confirmed as occurring in Mexico.
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Affiliation(s)
- Raymond B Nagle
- Department of Pathology, University of Arizona, Tucson, AZ, USA University of Arizona Tucson United States of America
| | - B Christian Schmidt
- Canadian National Collection of Insects, Arachnids and Nematodes, Agriculture and Agri-Food Canada, K.W. Neatby Bldg., 960 Carling Ave., Ottawa, ON, Canada K1A 0C6, USA Canadian National Collection of Insects, Arachnids and Nematodes Ottawa Canada
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Huber J, Dettman DL, Williams DG, Hultine KR. Gas exchange characteristics of giant cacti species varying in stem morphology and life history strategy. Am J Bot 2018; 105:1688-1702. [PMID: 30304560 DOI: 10.1002/ajb2.1166] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 06/28/2018] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Giant cacti species possess long cylindrical stems that store massive amounts of water and other resources to draw on for photosynthesis, growth, and reproduction during hot and dry conditions. Across all giant cacti taxa, stem photosynthetic surface area to volume ratio (S:V) varies by several fold. This broad morphological diversity leads to the hypothesis that giant cacti function along a predictable resource use continuum from a "safe" strategy reflected in low S:V, low relative growth rates (RGR), and low net assimilation rates (Anet ) to a high-risk strategy that is reflected in high S:V, RGR, and Anet . METHODS To test this hypothesis, whole-plant gas exchange, chlorophyll fluorescence, and whole-spine-tissue carbon isotope ratios (δ13 C) were measured in four giant cacti species varying in stem morphology and RGR. Measurements were conducted on five well-watered, potted plants per species. KEY RESULTS Under conditions of mild diel temperatures and low atmospheric vapor pressure deficit, Anet , transpiration (E), and stomatal conductance (Gs ) were significantly higher, and water-use efficiency (Anet : Gs ) was lower in fast-growing, multi-stemmed species compared to the slower growing, single-stemmed species. However, under warmer, less optimal conditions, gas exchange converged between stem types, and neither δ13 C nor chlorophyll fluorescence varied among species. CONCLUSIONS The results add to a growing body of evidence that succulent-stemmed plants function along a similar economic spectrum as leaf-bearing plants such that functional traits including stem RGR, longevity, morphology, and gas exchange are correlated across species with varying life-history strategies.
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Affiliation(s)
- John Huber
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ, USA
- Department of Geosciences, University of Arizona, Tucson, AZ, USA
| | - David L Dettman
- Department of Geosciences, University of Arizona, Tucson, AZ, USA
| | | | - Kevin R Hultine
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ, USA
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Rowe HI, Tluczek M, Broatch J, Gruber D, Jones S, Langenfeld D, McNamara P, Weinstein L. Comparison of trailside degradation across a gradient of trail use in the Sonoran Desert. J Environ Manage 2018; 207:292-302. [PMID: 29182976 DOI: 10.1016/j.jenvman.2017.11.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 10/13/2017] [Accepted: 11/10/2017] [Indexed: 06/07/2023]
Abstract
As recreational visitation to the Sonoran Desert increases, the concern of scientists, managers and advocates who manage its natural resources deepens. Although many studies have been conducted on trampling of undisturbed vegetation and the effects of trails on adjacent plant and soil communities, little such research has been conducted in the arid southwest. We sampled nine 450-m trail segments with different visitation levels in Scottsdale's McDowell Sonoran Preserve over three years to understand the effects of visitation on soil erosion, trailside soil crusts and plant communities. Soil crust was reduced by 27-34% near medium and high use trails (an estimated peak rate of 13-70 visitors per hour) compared with control plots, but there was less than 1% reduction near low use trails (peak rate of two to four visitors per hour). We did not detect soil erosion in the center 80% of the trampled area of any of the trails. The number of perennial plant species dropped by less than one plant species on average, but perennial plant cover decreased by 7.5% in trailside plots compared with control plots 6 m off-trail. At the current levels of visitation, the primary management focus should be keeping people on the originally constructed trail tread surface to reduce impact to adjacent soil crusts.
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Affiliation(s)
| | | | - Jennifer Broatch
- School of Mathematical and Natural Sciences, Arizona State University at the West Campus, Glendale, AZ, USA
| | - Dan Gruber
- McDowell Sonoran Conservancy, Scottsdale, AZ, USA
| | - Steve Jones
- McDowell Sonoran Conservancy, Scottsdale, AZ, USA
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Winkler DE, Conver JL, Huxman TE, Swann DE. The interaction of drought and habitat explain space-time patterns of establishment in saguaro (Carnegiea gigantea). Ecology 2018; 99:621-631. [PMID: 29281753 DOI: 10.1002/ecy.2124] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 11/09/2017] [Accepted: 12/08/2017] [Indexed: 11/05/2022]
Abstract
The long-lived columnar saguaro cactus (Carnegiea gigantea) is among the most studied plants in the world. Long-term studies have shown saguaro establishment to be generally episodic and strongly influenced by precipitation and temperature. Water limitation through lower-than-average seasonal rainfall and elevated temperatures increasing evaporative loss can reduce survivorship of recent germinates. Thus, multi-year, extended drought could cause populations to decline as older saguaros die without replacement. Previous studies have related establishment to temporal variation in rainfall, but most studies have been on non-randomized plots in ideal habitat and thus might not have captured the full variability within the local area. We studied how saguaro establishment varied in space and which habitat features may buffer responses to drought on 36 4-ha plots located randomly across an elevation gradient, including substantial replication in landscape position (bajada, foothills, and slopes) in the two disjunct districts of Saguaro National Park in southern Arizona, USA. Recent, severe drought coincided with drastic declines in saguaro establishment across this ~25,000-ha area. Establishment patterns derived from the park-wide data set was strongly correlated with drought, but the Park's two districts and diversity of plots demonstrated substantially different population outcomes. Saguaro establishment was best explained by the interaction of drought and habitat type; establishment in bajada and foothill plots dropped to near-zero under the most severe periods of water limitation but remained higher in slope plots during the same time span. Combined with saguaro density estimates, these data suggest that the most suitable habitat type for saguaro establishment shifted to higher elevations during the time span of the recent drought. These results place into context the extent to which historical patterns of demography provide insight into future population dynamics in a changing climate and reveal the importance of understanding dynamics across the distribution of possible local habitat types with response to variation in weather.
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Affiliation(s)
- Daniel E Winkler
- Department of Ecology & Evolutionary Biology, University of California, Irvine, 321 Steinhaus Hall, Irvine, California, 92697, USA.,Canyonlands Research Station, Southwest Biological Science Center, United States Geological Survey, 2290 S West Resource Boulevard, Moab, Utah, 84532, USA
| | - Joshua L Conver
- Department of Geography and GIS, University of Cincinnati, 401 Braunstein Hall, Cincinnati, Ohio, 45221, USA
| | - Travis E Huxman
- Department of Ecology & Evolutionary Biology, University of California, Irvine, 321 Steinhaus Hall, Irvine, California, 92697, USA
| | - Don E Swann
- Saguaro National Park, 3693 South Old Spanish Trail, Tucson, Arizona, 85730, USA
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25
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Horst JL, Venable DL. Frequency-dependent seed predation by rodents on Sonoran Desert winter annual plants. Ecology 2017; 99:196-203. [PMID: 29083479 DOI: 10.1002/ecy.2066] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Revised: 07/31/2017] [Accepted: 09/29/2017] [Indexed: 11/11/2022]
Abstract
Numerous mechanisms may allow species to coexist. We tested for frequency-dependent predation, a mechanism predicted by theory and established as a foraging behavior for many types of animals. Our field test included multiple prey species exposed in situ to multiple predator species and individuals to determine whether the prey species experienced predation patterns that were frequency dependent. The prey were seeds of three species of Sonoran Desert winter annual plants while the predator species were a guild of nocturnal seed foraging heteromyid and murid rodents that co-occur naturally in the same community as the desert annuals at Tumamoc Hill near Tucson. Seeds of one species were much preferred over the other two. Nonetheless, we found the net effect of rodent foraging to be positively frequency dependent (the preference for each species is higher when it is common than when it is uncommon) as has been previously hypothesized. This frequency-dependent predation should function as a species coexistence promoting mechanism in concert with the storage effect that has been previously demonstrated for this system.
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Affiliation(s)
- Jonathan L Horst
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, 85721, USA
| | - D Lawrence Venable
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, 85721, USA
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26
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Flesch AD, Rosen PC, Holm P. Long-term changes in abundances of Sonoran Desert lizards reveal complex responses to climatic variation. Glob Chang Biol 2017; 23:5492-5508. [PMID: 28712135 DOI: 10.1111/gcb.13813] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 06/13/2017] [Indexed: 06/07/2023]
Abstract
Understanding how climatic variation affects animal populations and communities is essential for addressing threats posed by climate change, especially in systems where impacts are projected to be high. We evaluated abundance dynamics of five common species of diurnal lizards over 25 years in a Sonoran Desert transition zone where precipitation decreased and temperature increased across time, and assessed hypotheses for the influence of climatic flux on spatiotemporal variation in abundances. We repeatedly surveyed lizards in spring and summer of each year at up to 32 sites, and used hierarchical mixture models to estimate detection probabilities, abundances, and population growth rates. Among terrestrial species, abundances of a short-lived, winter-spring breeder increased markedly by an estimated 237%-285% across time, while two larger spring-summer breeders with higher thermal preferences declined by up to 64%. Abundances of two arboreal species that occupy shaded and thus sheltered microhabitats fluctuated but did not decline systematically. Abundances of all species increased with precipitation at short lag times (1-1.5 years) likely due to enhanced food availability, but often declined after periods of high precipitation at longer lag times (2-4 years) likely due to predation and other biotic pressures. Although rising maximum daily temperatures (Tmax ) are expected to drive global declines of lizards, associations with Tmax were variable and weak for most species. Instead, abundances of all species declined with rising daily minimum temperatures, suggesting degradation of cool refugia imposed widespread metabolic or other costs. Our results suggest climate warming and drying are having major impacts on lizard communities by driving declines in species with traits that augment exposure to abiotic extremes and by modifying species interactions. The complexity of patterns we report indicates that evaluating and responding to the influence of climate change on biodiversity must consider a broad array of ecological processes.
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Affiliation(s)
- Aaron D Flesch
- The Desert Laboratory, School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, USA
| | - Philip C Rosen
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, USA
| | - Peter Holm
- National Park Service, Organ Pipe Cactus National Monument, Ajo, AZ, USA
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27
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Valdivia-Carrillo T, García-De León FJ, Blázquez MC, Gutiérrez-Flores C, González Zamorano P. Phylogeography and Ecological Niche Modeling of the Desert Iguana (Dipsosaurus dorsalis, Baird & Girard 1852) in the Baja California Peninsula. J Hered 2017; 108:640-649. [PMID: 28821185 DOI: 10.1093/jhered/esx064] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 07/13/2017] [Indexed: 11/14/2022] Open
Abstract
Understanding the factors that explain the patterns of genetic structure or phylogeographic breaks at an intraspecific level is key to inferring the mechanisms of population differentiation in its early stages. These topics have been well studied in the Baja California region, with vicariance and the dispersal ability of individuals being the prevailing hypothesis for phylogeographic breaks. In this study, we evaluated the phylogeographic patterns in the desert iguana (Dipsosaurus dorsalis), a species with a recent history in the region and spatial variation in life history traits. We analyzed a total of 307 individuals collected throughout 19 localities across the Baja California Peninsula with 15 microsatellite DNA markers. Our data reveal the existence of 3 geographically discrete genetic populations with moderate gene flow and an isolation-by-distance pattern presumably produced by the occurrence of a refugium in the Cape region during the Pleistocene Last Glacial Maximum. Bayesian methods and ecological niche modeling were used to assess the relationship between population genetic structure and present and past climatic preferences of the desert iguana. We found that the present climatic heterogeneity of the Baja California Peninsula has a marked influence on the population genetic structure of the species, suggesting that there are alternative explanations besides vicariance. The information obtained in this study provides data allowing a better understanding of how historical population processes in the Baja California Peninsula can be understood from an ecological perspective.
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Affiliation(s)
- Tania Valdivia-Carrillo
- Laboratorio de Genética para la Conservación, Programa de Planeación Ambiental y Conservación, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, Baja California Sur, México; Laboratorio de Ecología del Comportamiento, Programa de Planeación Ambiental y Conservación, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, Baja California Sur, México; Laboratorio de Sistemas de Información Geográfica, Programa de Planeación Ambiental y Conservación, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, Baja California Sur, México
| | - Francisco J García-De León
- Laboratorio de Genética para la Conservación, Programa de Planeación Ambiental y Conservación, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, Baja California Sur, México; Laboratorio de Ecología del Comportamiento, Programa de Planeación Ambiental y Conservación, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, Baja California Sur, México; Laboratorio de Sistemas de Información Geográfica, Programa de Planeación Ambiental y Conservación, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, Baja California Sur, México
| | - Ma Carmen Blázquez
- Laboratorio de Genética para la Conservación, Programa de Planeación Ambiental y Conservación, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, Baja California Sur, México; Laboratorio de Ecología del Comportamiento, Programa de Planeación Ambiental y Conservación, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, Baja California Sur, México; Laboratorio de Sistemas de Información Geográfica, Programa de Planeación Ambiental y Conservación, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, Baja California Sur, México
| | - Carina Gutiérrez-Flores
- Laboratorio de Genética para la Conservación, Programa de Planeación Ambiental y Conservación, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, Baja California Sur, México; Laboratorio de Ecología del Comportamiento, Programa de Planeación Ambiental y Conservación, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, Baja California Sur, México; Laboratorio de Sistemas de Información Geográfica, Programa de Planeación Ambiental y Conservación, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, Baja California Sur, México
| | - Patricia González Zamorano
- Laboratorio de Genética para la Conservación, Programa de Planeación Ambiental y Conservación, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, Baja California Sur, México; Laboratorio de Ecología del Comportamiento, Programa de Planeación Ambiental y Conservación, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, Baja California Sur, México; Laboratorio de Sistemas de Información Geográfica, Programa de Planeación Ambiental y Conservación, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, Baja California Sur, México
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28
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Munson SM, Sankey TT, Xian G, Villarreal ML, Homer CG. Decadal shifts in grass and woody plant cover are driven by prolonged drying and modified by topo-edaphic properties. Ecol Appl 2016; 26:2478-2492. [PMID: 27907253 DOI: 10.1002/eap.1389] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 05/23/2016] [Accepted: 06/01/2016] [Indexed: 06/06/2023]
Abstract
Woody plant encroachment and overall declines in perennial vegetation in dryland regions can alter ecosystem properties and indicate land degradation, but the causes of these shifts remain controversial. Determining how changes in the abundance and distribution of grass and woody plants are influenced by conditions that regulate water availability at a regional scale provides a baseline to compare how management actions alter the composition of these vegetation types at a more local scale and can be used to predict future shifts under climate change. Using a remote-sensing-based approach, we assessed the balance between grasses and woody plants and how climate and topo-edaphic conditions affected their abundances across the northern Sonoran Desert from 1989 to 2009. Despite widespread woody plant encroachment in this region over the last 150 years, we found that leguminous trees, including mesquite (Prosopis spp.), declined in cover in areas with prolonged drying conditions during the early 21st century. Creosote bush (Larrea tridentata) also had moderate decreases with prolonged drying but was buffered from changes on soils with low clay that promote infiltration and high available water capacity that allows for retention of water at depth. Perennial grasses have expanded and contracted over the last two decades in response to summer precipitation and were especially dynamic on shallow soils with high clay that have large fluctuations in water availability. Our results suggest that topo-edaphic properties can amplify or ameliorate climate-induced changes in woody plants and perennial grasses. Understanding these relationships has important implications for ecosystem function under climate change in the southwestern USA and can inform management efforts to regulate grass and woody plant abundances.
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Affiliation(s)
- Seth M Munson
- U.S. Geological Survey, Southwest Biological Science Center, 2255 N. Gemini Drive, Flagstaff, Arizona, 86001, USA
| | - Temuulen T Sankey
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, 1295 South Knoles Drive, Flagstaff, Arizona, 86011, USA
| | - George Xian
- U.S. Geological Survey, Earth Resources Observation and Science Center, 47914 252nd Street, Sioux Falls, South Dakota, 57198, USA
| | - Miguel L Villarreal
- U.S. Geological Survey, Western Geographic Science Center, 345 Middlefield Road, MS #531, Menlo Park, California, 94025, USA
| | - Collin G Homer
- U.S. Geological Survey, Earth Resources Observation and Science Center, 47914 252nd Street, Sioux Falls, South Dakota, 57198, USA
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29
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Gremer JR, Bradford JB, Munson SM, Duniway MC. Desert grassland responses to climate and soil moisture suggest divergent vulnerabilities across the southwestern United States. Glob Chang Biol 2015; 21:4049-4062. [PMID: 26183431 DOI: 10.1111/gcb.13043] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 05/18/2015] [Accepted: 05/27/2015] [Indexed: 06/04/2023]
Abstract
Climate change predictions include warming and drying trends, which are expected to be particularly pronounced in the southwestern United States. In this region, grassland dynamics are tightly linked to available moisture, yet it has proven difficult to resolve what aspects of climate drive vegetation change. In part, this is because it is unclear how heterogeneity in soils affects plant responses to climate. Here, we combine climate and soil properties with a mechanistic soil water model to explain temporal fluctuations in perennial grass cover, quantify where and the degree to which incorporating soil water dynamics enhances our ability to understand temporal patterns, and explore the potential consequences of climate change by assessing future trajectories of important climate and soil water variables. Our analyses focused on long-term (20-56 years) perennial grass dynamics across the Colorado Plateau, Sonoran, and Chihuahuan Desert regions. Our results suggest that climate variability has negative effects on grass cover, and that precipitation subsidies that extend growing seasons are beneficial. Soil water metrics, including the number of dry days and availability of water from deeper (>30 cm) soil layers, explained additional grass cover variability. While individual climate variables were ranked as more important in explaining grass cover, collectively soil water accounted for 40-60% of the total explained variance. Soil water conditions were more useful for understanding the responses of C3 than C4 grass species. Projections of water balance variables under climate change indicate that conditions that currently support perennial grasses will be less common in the future, and these altered conditions will be more pronounced in the Chihuahuan Desert and Colorado Plateau. We conclude that incorporating multiple aspects of climate and accounting for soil variability can improve our ability to understand patterns, identify areas of vulnerability, and predict the future of desert grasslands.
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Affiliation(s)
- Jennifer R Gremer
- U.S. Geological Survey, Southwest Biological Science Center, Flagstaff, AZ, 86001, USA
| | - John B Bradford
- U.S. Geological Survey, Southwest Biological Science Center, Flagstaff, AZ, 86001, USA
| | - Seth M Munson
- U.S. Geological Survey, Southwest Biological Science Center, Flagstaff, AZ, 86001, USA
| | - Michael C Duniway
- U.S. Geological Survey, Southwest Biological Science Center, Moab, UT, 84532, USA
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Edwards T, Berry KH, Inman RD, Esque TC, Nussear KE, Jones CA, Culver M. Testing Taxon Tenacity of Tortoises: evidence for a geographical selection gradient at a secondary contact zone. Ecol Evol 2015; 5:2095-114. [PMID: 26045959 PMCID: PMC4449762 DOI: 10.1002/ece3.1500] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 03/10/2015] [Accepted: 03/11/2015] [Indexed: 11/30/2022] Open
Abstract
We examined a secondary contact zone between two species of desert tortoise, Gopherus agassizii and G. morafkai. The taxa were isolated from a common ancestor during the formation of the Colorado River (4–8 mya) and are a classic example of allopatric speciation. However, an anomalous population of G. agassizii comes into secondary contact with G. morafkai east of the Colorado River in the Black Mountains of Arizona and provides an opportunity to examine reinforcement of species' boundaries under natural conditions. We sampled 234 tortoises representing G. agassizii in California (n - 103), G. morafkai in Arizona (n - 78), and 53 individuals of undetermined assignment in the contact zone including and surrounding the Black Mountains. We genotyped individuals for 25 STR loci and determined maternal lineage using mtDNA sequence data. We performed multilocus genetic clustering analyses and used multiple statistical methods to detect levels of hybridization. We tested hypotheses about habitat use between G. agassizii and G. morafkai in the region where they co-occur using habitat suitability models. Gopherus agassizii and G. morafkai maintain independent taxonomic identities likely due to ecological niche partitioning, and the maintenance of the hybrid zone is best described by a geographical selection gradient model.
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Affiliation(s)
- Taylor Edwards
- School of Natural Resources and the Environment, The University of Arizona Tucson, Arizona, 85721 ; University of Arizona Genetics Core, University of Arizona 1657 E. Helen Street, Tucson, Arizona, 85721
| | - Kristin H Berry
- Western Ecological Research Center, U.S. Geological Survey Falcon Business Park, 21803 Cactus Avenue, Suite F, Riverside, California, 92518
| | - Richard D Inman
- Western Ecological Research Center, U.S. Geological Survey 160 North Stephanie St., Henderson, Nevada, 89074
| | - Todd C Esque
- Western Ecological Research Center, U.S. Geological Survey 160 North Stephanie St., Henderson, Nevada, 89074
| | - Kenneth E Nussear
- Western Ecological Research Center, U.S. Geological Survey 160 North Stephanie St., Henderson, Nevada, 89074
| | - Cristina A Jones
- School of Natural Resources and the Environment, The University of Arizona Tucson, Arizona, 85721 ; Arizona Game and Fish Department, Nongame Wildlife Branch Phoenix, Arizona, 85086
| | - Melanie Culver
- School of Natural Resources and the Environment, The University of Arizona Tucson, Arizona, 85721 ; Arizona Cooperative Fish and Wildlife Research Unit, U.S. Geological Survey, University of Arizona Tucson, Arizona, 85721
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31
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Still SM. Two new desert Eschscholzia (Papaveraceae) from southwestern North America. PhytoKeys 2014; 35:45-56. [PMID: 24843288 PMCID: PMC4023337 DOI: 10.3897/phytokeys.35.6751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 02/24/2014] [Indexed: 06/03/2023]
Abstract
Two new species of Eschscholzia are described. Both are found in the deserts of California and one extends outside the state boundary into Arizona. Eschscholzia androuxii Still, sp. nov. is found mainly in and around Joshua Tree National Park in Riverside and San Bernardino counties. Eschscholzia papastillii Still, sp. nov. is found from the northern Mojave south through Joshua Tree National Park to central Imperial County. Both are annuals found in coarse, sandy soil and have yellow flowers typical of desert Eschscholzia. Eschscholzia papastillii has an expanded receptacular rim similar to that of Eschscholzia californica. Eschscholzia androuxii has anthocyanin bands around the stamen filaments.
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Affiliation(s)
- Shannon M. Still
- Department of Plant Science and Conservation, Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL 60022
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32
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Etges WJ. No boundaries: genomes, organisms, and ecological interactions responsible for divergence and reproductive isolation. J Hered 2014; 105 Suppl 1:756-70. [PMID: 25149252 PMCID: PMC4170711 DOI: 10.1093/jhered/esu039] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 05/31/2014] [Indexed: 12/23/2022] Open
Abstract
Revealing the genetic basis of traits that cause reproductive isolation, particularly premating or sexual isolation, usually involves the same challenges as most attempts at genotype-phenotype mapping and so requires knowledge of how these traits are expressed in different individuals, populations, and environments, particularly under natural conditions. Genetic dissection of speciation phenotypes thus requires understanding of the internal and external contexts in which underlying genetic elements are expressed. Gene expression is a product of complex interacting factors internal and external to the organism including developmental programs, the genetic background including nuclear-cytotype interactions, epistatic relationships, interactions among individuals or social effects, stochasticity, and prevailing variation in ecological conditions. Understanding of genomic divergence associated with reproductive isolation will be facilitated by functional expression analysis of annotated genomes in organisms with well-studied evolutionary histories, phylogenetic affinities, and known patterns of ecological variation throughout their life cycles. I review progress and prospects for understanding the pervasive role of host plant use on genetic and phenotypic expression of reproductive isolating mechanisms in cactophilic Drosophila mojavensis and suggest how this system can be used as a model for revealing the genetic basis for species formation in organisms where speciation phenotypes are under the joint influences of genetic and environmental factors.
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Affiliation(s)
- William J Etges
- From Program in Ecology and Evolutionary Biology, Department of Biological Sciences, 1 University of Arkansas, Fayetteville, AR.
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33
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Arrigo N, Therrien J, Anderson CL, Windham MD, Haufler CH, Barker MS. A total evidence approach to understanding phylogenetic relationships and ecological diversity in Selaginella subg. Tetragonostachys. Am J Bot 2013; 100:1672-82. [PMID: 23935110 DOI: 10.3732/ajb.1200426] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
PREMISE OF THE STUDY Several members of Selaginella are renowned for their ability to survive extreme drought and "resurrect" when conditions improve. Many of these belong to subgenus Tetragonostachys, a group of ∼45 species primarily found in North and Central America, with substantial diversity in the Sonoran and Chihuahuan Deserts. We evaluated the monophyly and the age of subgenus Tetragonostachys and assess how drought tolerance contributed to the evolution of this clade. METHODS Our study included most Tetragonostachys species, using plastid and nuclear sequences, fossil and herbarium records, and climate variables to describe the species diversity, phylogenetic relationships, divergence times, and climatic niche evolution in the subgenus. KEY RESULTS We found that subgenus Tetragonostachys forms a monophyletic group sister to Selaginella lepidophylla and may have diverged from other Selaginella because of a Gondwanan-Laurasian vicariance event ca. 240 mya. The North American radiation of Tetragonostachys appears to be much more recent and to have occurred during the Early Cretaceous-late Paleocene interval. We identified two significant and nested ecological niche shifts during the evolution of Tetragonostachys associated with extreme drought tolerance and a more recent shift to cold climates. Our analyses suggest that drought tolerance evolved in the warm deserts of southwest North America and may have been advantageous for colonization of cold and dry boreal climates. CONCLUSIONS Our investigation provides a foundation for future research addressing the genomics of ecological niche evolution and the potential role of reticulate evolution in Selaginella subgenus Tetragonostachys.
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Affiliation(s)
- Nils Arrigo
- Department of Ecology and Evolutionary Biology, University of Arizona, P.O. Box 210088, Tucson, Arizona 85721, USA
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Lücking R, Tehler A, Bungartz F, Rivas Plata E, Lumbsch HT. Journey from the West: did tropical Graphidaceae (lichenized Ascomycota: Ostropales) evolve from a saxicolous ancestor along the American Pacific coast? Am J Bot 2013; 100:844-856. [PMID: 23594913 DOI: 10.3732/ajb.1200548] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
PREMISE OF THE STUDY This study elucidates the phylogenetic position of a unique taxon of Graphidaceae occurring on rock in coastal desert areas, assessing its importance for our understanding of the evolution of the largest family of tropical lichenized fungi. • METHODS We used maximum likelihood and Bayesian approaches to reconstruct a three-gene phylogeny of Graphidaceae and a Bayesian molecular clock approach to estimate divergence dates for major clades, as well as Bayesian ancestral ecogeography state analysis. • KEY RESULTS The new genus Redonographa represents a new subfamily, Redonographoideae, sister to subfamily Graphidoideae. Redonographa is exclusively saxicolous and restricted to the American Pacific coast from California to central Chile, including Galapagos. It contains four species: Redonographa chilensis comb. nov., R. saxiseda comb. nov., R. saxorum comb. nov., and R. galapagoensis sp. nov. The genus Gymnographopsis, with a similar ecogeography but differing in excipular carbonization and chemistry, is also included in Redonographoideae, with the species G. chilena from Chile and G. latispora from South Africa. Molecular clock analysis indicates that Redonographoideae diverged from Graphidoideae about 132 million years ago (Ma) in the Early Cretaceous. • CONCLUSIONS The divergence date for subfamilies Redonographoideae and Graphidoideae coincides with the early breakup of Gondwana and ancient origin of the Atacama Desert. However, the common ancestor of Redonographoideae plus Graphidoideae was reconstructed to be tropical-epiphytic. Thus, even if Redonographoideae is subtropical-saxicolous, the hypothesis that Graphidoideae evolved from a subtropical-saxicolous ancestor is not supported.
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Affiliation(s)
- Robert Lücking
- Department of Botany, The Field Museum, 1400 South Lake Shore Drive, Chicago, IL 60605 USA.
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Richmond MP, Johnson S, Markow TA. Evolution of reproductive morphology among recently diverged taxa in the Drosophila mojavensis species cluster. Ecol Evol 2012; 2:397-408. [PMID: 22423332 PMCID: PMC3298951 DOI: 10.1002/ece3.93] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 11/09/2011] [Accepted: 11/23/2011] [Indexed: 11/18/2022] Open
Abstract
The morphological evolution of sexual traits informs studies of speciation due to the potential role of these characters in reproductive isolation. In the current study, we quantified and compared genitalic variation within the Drosophila mojavensis species cluster to infer the mode of evolution of the male aedeagus. This system is ideal for such studies due to the opportunity to test and compare levels of variation along a divergence continuum at various taxonomic levels within the group. Shape variation was quantified using elliptic Fourier descriptors and compared among the four D. mojavensis host races, and between D. mojavensis and its sister species Drosophila arizonae. Aedeagus shape was diagnostic for D. arizonae, and among three of the four D. mojavensis subspecies. In each of these cases, there was less variation within subspecies than among subspecies, which is consistent with the pattern predicted if genitalia are evolving according to a punctuated change model, and are involved with mate recognition. However, aedeagus shape in Drosophila mojavensis sonorensis was highly variable and broadly overlapping with the other three subspecies, suggesting aedeagus evolution in this subspecies is more complex and subject to additional evolutionary factors. These results are interpreted and discussed in the context of selection on mate recognition systems and the potential for failed copulation.
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Affiliation(s)
- Maxi Polihronakis Richmond
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California 92093
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Abstract
Freezing temperatures strongly influence vegetation in the hottest desert of North America, in part determining both its overall boundary and distributions of plant species within. To evaluate recent variability of freezing temperatures in this context, minimum temperature data from weather stations in the Sonoran Desert are examined. Data show widespread warming trends in winter and spring, decreased frequency of freezing temperatures, lengthening of the freeze-free season, and increased minimum temperatures per winter year. Local land use and multidecadal modes of the global climate system such as the Pacific decadal oscillation and the Atlantic multidecadal oscillation do not appear to be principal drivers of this warming. Minimum temperature variability in the Sonoran Desert does, however, correspond to global temperature variability attributed to human-dominated global warming. With warming expected to continue at faster rates throughout the 21st century, potential ecological responses may include contraction of the overall boundary of the Sonoran Desert in the south-east and expansion northward, eastward, and upward in elevation, as well as changes to distributions of plant species within and other characteristics of Sonoran Desert ecosystems. Potential trajectories of vegetation change in the Sonoran Desert region may be affected or made more difficult to predict by uncertain changes in warm season precipitation variability and fire. Opportunities now exist to investigate ecosystem response to regional climate disturbance, as well as to anticipate and plan for continued warming in the Sonoran Desert region.
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Affiliation(s)
- Jeremy L Weiss
- Department of Geosciences, University of Arizona, 1040 East 4th Street, Gould-Simpson Room 208, Tucson, AZ 85721, USA
| | - Jonathan T Overpeck
- Department of Geosciences, University of Arizona, 1040 East 4th Street, Gould-Simpson Room 208, Tucson, AZ 85721, USA
- Institute for the Study of Planet Earth, University of Arizona, 715 North Park Avenue, Tucson, AZ 85721, USA
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Bowers JE, Turner RM. The influence of climatic variability on local population dynamics of Cercidium microphyllum (foothill paloverde). Oecologia 2002; 130:105-113. [PMID: 28547015 DOI: 10.1007/s004420100779] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2001] [Accepted: 06/26/2001] [Indexed: 11/30/2022]
Abstract
This study investigated correlations among climatic variability, population age structure, and seedling survival of a dominant Sonoran Desert tree, Cercidium microphyllum (foothill paloverde), at Tucson, Arizona, USA. A major goal was to determine whether wet years promote seedling establishment and thereby determine population structure. Plant age was estimated from basal circumference for a sample of 980 living and dead trees in twelve 0.5-ha plots. Ages ranged from 1 to 181 years. Age frequency distribution showed that the population is in decline. Most (51.2%) of the 814 living trees were 40-80 years old; only 6.5% were younger than 20 years. The average age of the 166 dead trees was 78 years. Fifty-nine percent of dead trees were aged 60-100 years. Survival of newly emerged seedlings was monitored for 7 years in a 557-m2 permanent plot. Mean survival in the 1st year of life was 1.7%. Only 2 of 1,008 seedlings lived longer than 1 year. Length of survival was not correlated with rainfall. Residual regeneration, an index of the difference between predicted and observed cohort size, showed that regeneration was high during the first half of the twentieth century and poor after the mid-1950s. Trends in regeneration did not reflect interannual variation in seasonal temperature or rain before 1950, that is, in the years before urban warming. Taken together, the seedling study and the regeneration analysis suggest that local population dynamics reflect biotic factors to such an extent that population age structure might not always be a reliable clue to past climatic influences.
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Affiliation(s)
- Janice E Bowers
- U.S. Geological Survey, 1675 West Anklam Road, 85745, Tucson, AZ, USA
| | - Raymond M Turner
- U.S. Geological Survey, 1675 West Anklam Road, 85745, Tucson, AZ, USA
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Abstract
We report a new obligate pollination mutualism involving the senita cactus, Lophocereus schottii (Cactaceae, Pachyceereae), and the senita moth, Upiga virescens (Pyralidae, Glaphyriinae) in the Sonoran Desert and discuss the evolution of specialized pollination mutualisms. L. schottii is a night-blooming, self-incompatible columnar cactus. Beginning at sunset, its flowers are visited by U. virescens females, which collect pollen on specialized abdominal scales, actively deposit pollen on flower stigmas, and oviposit a single egg on a flower petal. Larvae spend 6 days eating ovules before exiting the fruit and pupating in a cactus branch. Hand-pollination and pollinator exclusion experiments at our study site near Bahia Kino, Sonora, Mexico, revealed that fruit set in L. schottii is likely to be resource limited. About 50% of hand-outcrossed and open-pollinated senita flowers abort by day 6 after flower opening. Results of exclusion experiments indicated that senita moths accounted for 75% of open-pollinated fruit set in 1995 with two species of halictid bees accounting for the remaining fruit set. In 1996, flowers usually closed before sunrise, and senita moths accounted for at least 90% of open-pollinated fruit set. The net outcome of the senita/senita moth interaction is mutualistic, with senita larvae destroying about 30% of the seeds resulting from pollination by senita moths. Comparison of the senita system with the yucca/yucca moth mutualism reveals many similarities, including reduced nectar production, active pollination, and limited seed destruction. The independent evolution of many of the same features in the two systems suggests that a common pathway exists for the evolution of these highly specialized pollination mutualisms. Nocturnal flower opening, self-incompatible breeding systems, and resource-limited fruit production appear to be important during this evolution.
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