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Arnold PA, Wang S, Notarnicola RF, Nicotra AB, Kruuk LEB. Testing the evolutionary potential of an alpine plant: phenotypic plasticity in response to growth temperature outweighs parental environmental effects and other genetic causes of variation. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:5971-5988. [PMID: 38946283 PMCID: PMC11427842 DOI: 10.1093/jxb/erae290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 06/28/2024] [Indexed: 07/02/2024]
Abstract
Phenotypic plasticity and rapid evolution are fundamental processes by which organisms can maintain their function and fitness in the face of environmental changes. Here we quantified the plasticity and evolutionary potential of an alpine herb Wahlenbergia ceracea. Utilizing its mixed-mating system, we generated outcrossed and self-pollinated families that were grown in either cool or warm environments, and that had parents that had also been grown in either cool or warm environments. We then analysed the contribution of environmental and genetic factors to variation in a range of phenotypic traits including phenology, leaf mass per area, photosynthetic function, thermal tolerance, and reproductive fitness. The strongest effect was that of current growth temperature, indicating strong phenotypic plasticity. All traits except thermal tolerance were plastic, whereby warm-grown plants flowered earlier, grew larger, and produced more reproductive stems compared with cool-grown plants. Flowering onset and biomass were heritable and under selection, with early flowering and larger plants having higher relative fitness. There was little evidence for transgenerational plasticity, maternal effects, or genotype×environment interactions. Inbreeding delayed flowering and reduced reproductive fitness and biomass. Overall, we found that W. ceracea has the capacity to respond rapidly to climate warming via plasticity, and the potential for evolutionary change.
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Affiliation(s)
- Pieter A Arnold
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Shuo Wang
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
- Liaoning Key Laboratory for Biological Invasions and Global Changes, College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, Liaoning Province 110866, China
| | - Rocco F Notarnicola
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
- Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Adrienne B Nicotra
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Loeske E B Kruuk
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
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2
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Denney DA, Patel P, Anderson JT. Elevated [CO 2] and temperature augment gas exchange and shift the fitness landscape in a montane forb. THE NEW PHYTOLOGIST 2024; 243:58-71. [PMID: 38655662 DOI: 10.1111/nph.19765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 03/29/2024] [Indexed: 04/26/2024]
Abstract
Climate change is simultaneously increasing carbon dioxide concentrations ([CO2]) and temperature. These factors could interact to influence plant physiology and performance. Alternatively, increased [CO2] may offset costs associated with elevated temperatures. Furthermore, the interaction between elevated temperature and [CO2] may differentially affect populations from along an elevational gradient and disrupt local adaptation. We conducted a multifactorial growth chamber experiment to examine the interactive effects of temperature and [CO2] on fitness and ecophysiology of diverse accessions of Boechera stricta (Brassicaceae) sourced from a broad elevational gradient in Colorado. We tested whether increased [CO2] would enhance photosynthesis across accessions, and whether warmer conditions would depress the fitness of high-elevation accessions owing to steep reductions in temperature with increasing elevation in this system. Elevational clines in [CO2] are not as evident, making it challenging to predict how locally adapted ecotypes will respond to elevated [CO2]. This experiment revealed that elevated [CO2] increased photosynthesis and intrinsic water use efficiency across all accessions. However, these instantaneous responses to treatments did not translate to changes in fitness. Instead, increased temperatures reduced the probability of reproduction for all accessions. Elevated [CO2] and increased temperatures interacted to shift the adaptive landscape, favoring lower elevation accessions for the probability of survival and fecundity. Our results suggest that elevated temperatures and [CO2] associated with climate change could have severe negative consequences, especially for high-elevation populations.
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Affiliation(s)
- Derek A Denney
- Department of Plant Biology, University of Georgia, Athens, GA, 30602, USA
| | - Pratik Patel
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA
| | - Jill T Anderson
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA
- Odum School of Ecology, University of Georgia, Athens, GA, 30602, USA
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3
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Laughlin DC. Unifying functional and population ecology to test the adaptive value of traits. Biol Rev Camb Philos Soc 2024. [PMID: 38855941 DOI: 10.1111/brv.13107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 05/23/2024] [Accepted: 05/29/2024] [Indexed: 06/11/2024]
Abstract
Plant strategies are phenotypes shaped by natural selection that enable populations to persist in a given environment. Plant strategy theory is essential for understanding the assembly of plant communities, predicting plant responses to climate change, and enhancing the restoration of our degrading biosphere. However, models of plant strategies vary widely and have tended to emphasize either functional traits or life-history traits at the expense of integrating both into a general framework to improve our ecological and evolutionary understanding of plant form and function. Advancing our understanding of plant strategies will require investment in two complementary research agendas that together will unify functional ecology and population ecology. First, we must determine what is phenotypically possible by quantifying the dimensionality of plant traits. This step requires dense taxonomic sampling of traits on species representing the broad diversity of phylogenetic clades, environmental gradients, and geographical regions found across Earth. It is important that we continue to sample traits locally and share data globally to fill biased gaps in trait databases. Second, we must test the power of traits for explaining species distributions, demographic rates, and population growth rates across gradients of resource limitation, disturbance regimes, temperature, vegetation density, and frequencies of other strategies. This step requires thoughtful, theory-driven empiricism. Reciprocal transplant experiments beyond the native range and synthetic demographic modelling are the most powerful methods to determine how trait-by-environment interactions influence fitness. Moving beyond easy-to-measure traits and evaluating the traits that are under the strongest ecological selection within different environmental contexts will improve our understanding of plant adaptations. Plant strategy theory is poised to (i) unpack the multiple dimensions of productivity and disturbance gradients and differentiate adaptations to climate and resource limitation from adaptations to disturbance, (ii) distinguish between the fundamental and realized niches of phenotypes, and (iii) articulate the distinctions and relationships between functional traits and life-history traits.
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Affiliation(s)
- Daniel C Laughlin
- Botany Department, University of Wyoming, Laramie, Wyoming, 82071, USA
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4
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Lesage JC, Hayes GF, Holl KD. Native annual forbs decline in California coastal prairies over 15 years despite grazing. PLoS One 2022; 17:e0278608. [PMID: 36472993 PMCID: PMC9725146 DOI: 10.1371/journal.pone.0278608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022] Open
Abstract
Livestock grazing is often used as a land management tool to maximize vegetation diversity in grassland ecosystems worldwide. Prior research has shown that cattle grazing benefits native annual forb species in California's coastal prairies, but drought and increasing aridity may alter this relationship. In 2016 and 2017, we resurveyed the vegetation structure, native annual forb cover, and native annual forb richness in ten grazed and ungrazed prairies that were originally measured in 2000 and 2001 along a 200-km gradient from Monterey to Sonoma counties in California. We found that grazed prairies continued to have significantly lower vegetation height and thatch depth than ungrazed prairies, and that shrub encroachment over the 15-year period was significantly greater in ungrazed prairies. Furthermore, grazed prairies continued to have greater native annual forb richness (4.9 species per site) than ungrazed sites (3.0 species per site), but native annual forb richness declined by 2.8 species per site in grazed prairies and 0.1 species per site in ungrazed prairies between survey periods. We suggest that severe drought and increasing aridity may be driving declines in native annual forb richness in grazed prairies. The species we recorded only in earlier surveys were disproportionately wetland-associated and had higher average specific leaf area than species that remained through the second survey period. Finally, the cover of native annual species increased regardless of whether prairies were grazed, suggesting that the high precipitation in 2017 may have benefitted the native annual forb species that persisted at sites between surveys. Our study shows that weather conditions affect the outcomes of land management strategies.
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Affiliation(s)
- Josephine C. Lesage
- Environmental Studies Department, University of California Santa Cruz, Santa Cruz, CA, United States of America
- Earth and Environmental Science Department, Clark College, Vancouver, WA, United States of America
| | - Grey F. Hayes
- Swanton Pacific Ranch, Cal Poly San Luis Obispo, Davenport, CA, United States of America
| | - Karen D. Holl
- Environmental Studies Department, University of California Santa Cruz, Santa Cruz, CA, United States of America
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5
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Early Differentiation of the Phenotypic Space and Performance of Juniperus thurifera Across Woodland-Expanding Areas. Ecosystems 2022. [DOI: 10.1007/s10021-022-00782-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractForest expansion after rural abandonment is changing landscapes, bringing new challenges and opportunities. Juvenile performance has an effect in the establishment of new forests and the subsequent acclimation of adult trees. However, most studies have focused on the performance of adult trees. Here, we analysed differences in the phenotypic trait space of juveniles across gradients of Juniperus thurifera woodland expansion and explored which traits shape juveniles’ performance, seeking specific drivers of such differentiation and the role of the ontogeny. Thus, we surveyed functional leaf and plant-size traits in 180 juveniles growing in 18 plots at three different tree density stages (mature woodland, recently established area and a transition zone between both) and recorded local environmental conditions around each individual. We also estimated their radial growth and resilience to drought (in terms of resistance, recovery and resilience) as performance indicators. We found no relevant effects of the study environmental variables, but we did find a shift in the phenotypic space among juveniles across the gradient, with taller crowns and higher amount of leaf N and δ13C at the expanding edge. This trait differentiation across the gradient implied higher performance of young trees growing in old agricultural fields, both in growth rate and drought resilience terms. Our results showed a relevant land-use legacy on early trait differentiation that shapes more efficient phenotypes in the expanding edge compared to those in mature woodlands, suggesting that the future of these new forests is not compromised under current conditions.
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Adaptive Strategies of Seedlings of Four Mediterranean Co-Occurring Tree Species in Response to Light and Moderate Drought: A Nursery Approach. FORESTS 2022. [DOI: 10.3390/f13020154] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In Mediterranean environments, light and water are clearly dominant ecological drivers of seedling growth and survival, and their interaction could modify productivity and forest composition. We examine the early response of seedlings of four co-occurring Mediterranean tree species (Pinus pinea, Juniperus thurifera, Quercus ilex and Quercus faginea) grown in the nursery to differing light and water availability conditions. Morphological (survival, height, biomass) and physiological (shoot midday water potential, net photosynthesis, transpiration rate, stomatal conductance, Fv/Fm, PSII and ETR) traits were studied, along with biomass allocation traits and drought resistance and plasticity indices. A significant effect of both factors was mainly shown for growth and morphological traits, while survival, physiological traits and allometry were affected by either water availability or light, being more remarkable the effect of water availability over light. Drought severely limited Q. faginea’s survival under both light intensities. The high plasticity of J. thurifera and Q. ilex seedlings to different light and water availability environments will confer these two species with an adaptive advantage in the early growth stages in comparison with P. pinea and Q. faginea seedlings. Thus, to maintain the codominance of the four species, silvicultural interventions should focus on the joint management of all of them.
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Phenology of Oenocarpus mapora H. Karst in Low-Terrace and High-Terrace Forests of the Madre de Dios Region, Peru. FORESTS 2021. [DOI: 10.3390/f12101424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Oenacarpus mapora H. Karst (O. mapora) is an Amazon palm with high economic and nutraceutical potential, from which the pulp and oil can be extracted. The objective of this study was to evaluate the phenology of O. mapora in low-terrace and high-terrace forests of the Madre de Dios Region, Peru. Two hundred sixteen individuals of O. mapora were monitored between June 2019 and January 2020, evaluating the presence of flower buds, open flowers, immature fruits and ripe fruits. Weighted mean analyses of the phenological pattern and correlation between climatic and phenological variables were carried out. Higher productivity mediated by a greater number of mature green leaves and bunches was observed in terrace forests located at a lower altitude. In both forest subtypes, flower buds and open flowers were continuous with a peak in July and August, respectively, during the dry season. In both habitats, unripe fruits were also continuous with a peak in September, while ripe fruits showed a peak in December and January in low-terrace and high-terrace forests, respectively, during the rainy season. Our findings show that flowering was continuous during the evaluated period, while fruiting increased during the rainy season associated with a greater number of days with precipitation.
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Havrilla CA, Munson SM, Yackulic EO, Butterfield BJ. Ontogenetic trait shifts: Seedlings display high trait variability during early stages of development. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13897] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Caroline A. Havrilla
- Southwest Biological Science Center US Geological Survey Flagstaff AZ USA
- Department of Forest and Rangeland Stewardship Colorado State University Fort Collins CO USA
- Department of Biological Sciences Northern Arizona University Flagstaff AZ USA
| | - Seth M. Munson
- Southwest Biological Science Center US Geological Survey Flagstaff AZ USA
| | - Ethan O. Yackulic
- Southwest Biological Science Center US Geological Survey Flagstaff AZ USA
- School of Earth and Sustainability Northern Arizona University Flagstaff AZ USA
| | - Bradley J. Butterfield
- Department of Biological Sciences Northern Arizona University Flagstaff AZ USA
- Center for Ecosystem Science and Society Northern Arizona University Flagstaff AZ USA
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9
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Impacts of invasive annual grasses and their litter vary by native functional strategy. Biol Invasions 2021. [DOI: 10.1007/s10530-021-02527-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractInvasive species may act as a functional filter on native communities by differentially affecting species with different trait values. Across environments, invasive plants typically display traits associated with high resource acquisition and fast growth. Conversely, native plants, especially those in water-limited environments, tend to adopt one of two functional strategies: fast growth during high resource availability to avoid stress (resource-acquisitive), or slow growth during resource-poor conditions to tolerate stress (resource-conservative). While invasive competition can be a strong filter on these groups, many invaders also alter the structure of native communities through their accumulation of litter. How fast-growing invaders with litter shift native functional communities remains unknown. To elucidate these functional shifts, I manipulated invasive annual grasses and their litter in an annual grassland and followed the demographic rates of six native annual forb species that varied in their functional strategy. Live grass competition alone decreased per capita growth rates of resource-acquisitive natives and had no effect on resource-conservative natives. The presence of litter, however, decreased growth rates in both functional types of natives, with stronger declines in resource-acquisitive species through differential effects on seed set and germination. Invaders in this system thus create an unfavorable environment for natives through litter, limiting the capacity of both resource-acquisitive and resource-conservative native forbs to maintain high population growth. These findings suggest that grass invasions have the potential to dramatically shift the functional composition of native communities through the time-lagged effects of their litter.
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10
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Wheeler MM, Collins SL, Grimm NB, Cook EM, Clark C, Sponseller RA, Hall SJ. Water and nitrogen shape winter annual plant diversity and community composition in near‐urban Sonoran Desert preserves. ECOL MONOGR 2021; 91:1-19. [DOI: 10.1002/ecm.1450] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Megan M. Wheeler
- School of Life Sciences Arizona State University P.O. Box 874501 Tempe Arizona 85287‐4501 USA
| | - Scott L. Collins
- Department of Biology University of New Mexico 1 University of New Mexico MSC03 2020 Albuquerque New Mexico 87131‐0001 USA
| | - Nancy B. Grimm
- School of Life Sciences Arizona State University P.O. Box 874501 Tempe Arizona 85287‐4501 USA
| | - Elizabeth M. Cook
- Department of Environmental Science Barnard College 3009 Broadway New York City New York 10027 USA
| | - Christopher Clark
- U.S. Environmental Protection Agency Office of Research and Development 1200 Pennsylvania Avenue Washington D.C. 20004 USA
| | - Ryan A. Sponseller
- Department of Ecology and Environmental Sciences Umeå University SE‐ 901 87 Umeå Sweden
| | - Sharon J. Hall
- School of Life Sciences Arizona State University P.O. Box 874501 Tempe Arizona 85287‐4501 USA
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11
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Funk JL, Larson JE, Ricks-Oddie J. Plant traits are differentially linked to performance in a semiarid ecosystem. Ecology 2021; 102:e03318. [PMID: 33630332 DOI: 10.1002/ecy.3318] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 10/21/2020] [Accepted: 12/06/2020] [Indexed: 11/09/2022]
Abstract
A central principle in trait-based ecology is that trait variation has an adaptive value. However, uncertainty over which plant traits influence individual performance across environmental gradients may limit our ability to use traits to infer ecological processes at larger scales. To better understand which traits are linked to performance under different precipitation regimes, we measured above- and belowground traits, growth, and reproductive allocation for four annual and four perennial species from a coastal sage scrub community in California under conditions of 50%, 100%, and 150% ambient precipitation. Across water treatments, annual species displayed morphological trait values consistent with high rates of resource acquisition (e.g., low leaf mass per area, low root tissue density, high specific root length), and aboveground measures of resource acquisition (including photosynthetic rate and leaf N concentration) were positively associated with plant performance (reproductive allocation). Results from a structural equation model demonstrated that leaf traits explained 38% of the variation in reproductive allocation across the water gradient in annual species, while root traits accounted for only 6%. Although roots play a critical role in water uptake, more work is needed to understand the mechanisms by which root trait variation can influence performance in water-limited environments. Perennial species showed lower trait plasticity than annuals across the water gradient and were more variable as a group in terms of trait-performance relationships, indicating that species rely on different functional strategies to respond to drought. Our finding that species identity drives much of the variation in trait values and trait-performance relationships across a water gradient may simplify efforts to model ecological processes, such as productivity, that are potentially influenced by environmentally induced shifts in trait values.
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Affiliation(s)
- Jennifer L Funk
- Schmid College of Science and Technology, Chapman University, Orange, California, 92866, USA.,Department of Plant Sciences, University of California, Davis, California, 95616, USA
| | - Julie E Larson
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, 80309, USA
| | - Joni Ricks-Oddie
- Center for Statistical Consulting, University of California, Irvine, California, 92797, USA.,Institute for Clinical and Translation Sciences, University of California, Irvine, California, 92797, USA
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12
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Di Biase L, Fattorini S, Cutini M, Bricca A. The Role of Inter- and Intraspecific Variations in Grassland Plant Functional Traits along an Elevational Gradient in a Mediterranean Mountain Area. PLANTS (BASEL, SWITZERLAND) 2021; 10:359. [PMID: 33668533 PMCID: PMC7917719 DOI: 10.3390/plants10020359] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/09/2021] [Accepted: 02/10/2021] [Indexed: 12/04/2022]
Abstract
Elevational gradients offer special opportunities to investigate the relative role of intraspecific and interspecific trait variations in relation to stress gradients. We used an altitudinal gradient in the Mediterranean (Mt Velino, Central Italy) to study (1) how community-weighted means (CWM) and nonweighted means (CM) vary with elevation for plant height, specific leaf area, and seed mass; and (2) how variation patterns differ for inter- and intraspecific functional variability. We tested (1) if elevation influences community functional composition on the basis of the adaptive value of plant traits and (2) if the latter shows intraspecific variations according to the species' ability to cope with local conditions. We found that different traits showed different patterns, which can be linked to the function they express. Differences between communities were influenced more by differences between their traits (CM) than by the relative species coverage (CWM). Both highest and lowest elevations were the most selective due to their particularly severe climatic conditions. Intermediate elevations were the most favorable thanks to less constraining climatic conditions. Interspecific trait variability was the most relevant component, indicating a low plant ability to cope with environmental variations through phenotypic plasticity.
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Affiliation(s)
- Letizia Di Biase
- Department of Life, Health and Environmental Sciences, University of L’Aquila, Via Vetoio, 67100 L’Aquila, Italy;
| | - Simone Fattorini
- Department of Life, Health and Environmental Sciences, University of L’Aquila, Via Vetoio, 67100 L’Aquila, Italy;
| | - Maurizio Cutini
- Department of Science, University of Roma Tre, Viale G. Marconi 446, 00146 Roma, Italy
| | - Alessandro Bricca
- School of Biosciences and Veterinary Medicine, University of Camerino, via Pontoni 5, 62032 Camerino, Italy;
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Mocko K, Jones CS. Do seedlings of larger geophytic species outperform smaller ones when challenged by drought? AMERICAN JOURNAL OF BOTANY 2021; 108:320-333. [PMID: 33638194 DOI: 10.1002/ajb2.1612] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 12/02/2020] [Indexed: 06/12/2023]
Abstract
PREMISE In semiarid regions, decreasing rainfall presents a challenge to perennial seedlings that must reach sufficient size to survive the first year's seasonal drought. Attaining a large storage organ size has been hypothesized to enhance drought resilience in geophytes, but building larger storage organs requires faster growth, but paradoxically, some traits that confer faster growth are highly sensitive to drought. We examined whether tuber size confers greater drought resilience in seedlings of four closely related geophytic species of Pelargonium. METHODS We imposed two drought treatments when seedlings were 2 months old: chronic low water and acute water restriction for 10 days. Plants in the acute dry-down treatment were then rewatered at control levels. We compared morphological and ecophysiological traits at 2, 3, and 6 months of age and used mixed-effects models to identify traits determining tuber biomass at dormancy. RESULTS Despite a 10-fold variation in size, species had similar physiological trait values under well-watered conditions. Chronic and acute droughts negatively affected tuber size at the end of the season, but only in the two species with large tubers. Chronic drought did not affect physiological traits of any species, but in response to acute drought, larger species showed reduced photosynthetic performance. Canopy area was the best predictor of final tuber biomass. CONCLUSIONS Contradictory to the hypothesis that large tubers provide greater drought resiliency, small Pelargonium seedlings actually had higher drought tolerance, although at the expense of more vigorous growth compared to species with larger tubers under well-watered conditions.
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Affiliation(s)
- Kerri Mocko
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, 06269, USA
| | - Cynthia S Jones
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, 06269, USA
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14
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Shryock DF, Washburn LK, DeFalco LA, Esque TC. Harnessing landscape genomics to identify future climate resilient genotypes in a desert annual. Mol Ecol 2021; 30:698-717. [PMID: 33007116 DOI: 10.1111/mec.15672] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 09/22/2020] [Accepted: 09/22/2020] [Indexed: 12/16/2022]
Abstract
Local adaptation features critically in shaping species responses to changing environments, complicating efforts to revegetate degraded areas. Rapid climate change poses an additional challenge that could reduce fitness of even locally sourced seeds in restoration. Predictive restoration strategies that apply seeds with favourable adaptations to future climate may promote long-term resilience. Landscape genomics is increasingly used to assess spatial patterns in local adaption and may represent a cost-efficient approach for identifying future-adapted genotypes. To demonstrate such an approach, we genotyped 760 plants from 64 Mojave Desert populations of the desert annual Plantago ovata. Genome scans on 5,960 SNPs identified 184 potentially adaptive loci related to climate and satellite vegetation metrics. Causal modelling indicated that variation in potentially adaptive loci was not confounded by isolation by distance or isolation by habitat resistance. A generalized dissimilarity model (GDM) attributed spatial turnover in potentially adaptive loci to temperature, precipitation and NDVI amplitude, a measure of vegetation green-up potential. By integrating a species distribution model (SDM), we find evidence that summer maximum temperature may both constrain the range of P. ovata and drive adaptive divergence in populations exposed to higher temperatures. Within the species' current range, warm-adapted genotypes are predicted to experience a fivefold expansion in climate niche by midcentury and could harbour key adaptations to cope with future climate. We recommend eight seed transfer zones and project each zone into its relative position in future climate. Prioritizing seed collection efforts on genotypes with expanding future habitat represents a promising strategy for restoration practitioners to address rapidly changing climates.
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Affiliation(s)
- Daniel F Shryock
- U.S. Geological Survey, Western Ecological Research Center, Henderson, NV, USA
| | | | - Lesley A DeFalco
- U.S. Geological Survey, Western Ecological Research Center, Henderson, NV, USA
| | - Todd C Esque
- U.S. Geological Survey, Western Ecological Research Center, Henderson, NV, USA
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15
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The Net Effect of Functional Traits on Fitness. Trends Ecol Evol 2020; 35:1037-1047. [PMID: 32807503 DOI: 10.1016/j.tree.2020.07.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 07/14/2020] [Accepted: 07/17/2020] [Indexed: 11/21/2022]
Abstract
Generalizing the effect of traits on performance across species may be achievable if traits explain variation in population fitness. However, testing relationships between traits and vital rates to infer effects on fitness can be misleading. Demographic trade-offs can generate variation in vital rates that yield equal population growth rates, thereby obscuring the net effect of traits on fitness. To address this problem, we describe a diversity of approaches to quantify intrinsic growth rates of plant populations, including experiments beyond range boundaries, density-dependent population models built from long-term demographic data, theoretical models, and methods that leverage widely available monitoring data. Linking plant traits directly to intrinsic growth rates is a fundamental step toward rigorous predictions of population dynamics and community assembly.
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16
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Jacquemyn H, Brys R. Lack of strong selection pressures maintains wide variation in floral traits in a food-deceptive orchid. ANNALS OF BOTANY 2020; 126:445-453. [PMID: 32333761 PMCID: PMC7424767 DOI: 10.1093/aob/mcaa080] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 04/23/2020] [Indexed: 05/27/2023]
Abstract
BACKGROUND AND AIMS Angiosperms vary remarkably in traits such as colour, size and shape of flowers, yet such variation generally tends to be low within species. In deceptive orchids, however, large variation in floral traits has been described, not only between but also within populations. Nonetheless, the factors driving variation in floral traits in deceptive orchids remain largely unclear. METHODS To identify determinants of variation in floral traits, we investigated patterns of fruit set and selection gradients in the food-deceptive orchid Orchis purpurea, which typically presents large within-population variation in the colour and size of the flowers. Using long-term data, fruit set was quantified in two populations over 16 consecutive years (2004-2019). Artificial hand pollination was performed to test the hypothesis that fruit set was pollinator-limited and that selfing led to decreased seed set and viability. Annual variation (2016-2019) in selection gradients was calculated for three colour traits (brightness, contrast and the number of spots on the labellum), flower size (spur length, labellum length and width) and plant size (number of flowers, plant height). KEY RESULTS Fruit set was, on average, low (~12 %) and severely pollinator-limited. Opportunities for selection varied strongly across years, but we found only weak evidence for selection on floral traits. In contrast, there was strong and consistent positive selection on floral display. Selfing led to reduced production of viable seeds and hence severe inbreeding depression (δ = 0.38). CONCLUSION Overall, these results demonstrate that the large variation in flower colour and size that is regularly observed in natural O. purpurea populations is maintained by the consistent lack of strong selection pressures on these traits through time.
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Affiliation(s)
- Hans Jacquemyn
- Department of Biology, Plant Conservation and Population Biology, KU Leuven, Leuven, Belgium
| | - Rein Brys
- Research Institute for Forest and Nature, Geraardsbergen, Belgium
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17
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Boonman CCF, Benítez‐López A, Schipper AM, Thuiller W, Anand M, Cerabolini BEL, Cornelissen JHC, Gonzalez‐Melo A, Hattingh WN, Higuchi P, Laughlin DC, Onipchenko VG, Peñuelas J, Poorter L, Soudzilovskaia NA, Huijbregts MAJ, Santini L. Assessing the reliability of predicted plant trait distributions at the global scale. GLOBAL ECOLOGY AND BIOGEOGRAPHY : A JOURNAL OF MACROECOLOGY 2020; 29:1034-1051. [PMID: 32612452 PMCID: PMC7319484 DOI: 10.1111/geb.13086] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 06/01/2023]
Abstract
AIM Predictions of plant traits over space and time are increasingly used to improve our understanding of plant community responses to global environmental change. A necessary step forward is to assess the reliability of global trait predictions. In this study, we predict community mean plant traits at the global scale and present a systematic evaluation of their reliability in terms of the accuracy of the models, ecological realism and various sources of uncertainty. LOCATION Global. TIME PERIOD Present. MAJOR TAXA STUDIED Vascular plants. METHODS We predicted global distributions of community mean specific leaf area, leaf nitrogen concentration, plant height and wood density with an ensemble modelling approach based on georeferenced, locally measured trait data representative of the plant community. We assessed the predictive performance of the models, the plausibility of predicted trait combinations, the influence of data quality, and the uncertainty across geographical space attributed to spatial extrapolation and diverging model predictions. RESULTS Ensemble predictions of community mean plant height, specific leaf area and wood density resulted in ecologically plausible trait-environment relationships and trait-trait combinations. Leaf nitrogen concentration, however, could not be predicted reliably. The ensemble approach was better at predicting community trait means than any of the individual modelling techniques, which varied greatly in predictive performance and led to divergent predictions, mostly in African deserts and the Arctic, where predictions were also extrapolated. High data quality (i.e., including intraspecific variability and a representative species sample) increased model performance by 28%. MAIN CONCLUSIONS Plant community traits can be predicted reliably at the global scale when using an ensemble approach and high-quality data for traits that mostly respond to large-scale environmental factors. We recommend applying ensemble forecasting to account for model uncertainty, using representative trait data, and more routinely assessing the reliability of trait predictions.
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Affiliation(s)
- Coline C. F. Boonman
- Department of Environmental ScienceInstitute for Water and Wetland ResearchRadboud UniversityNijmegenthe Netherlands
| | - Ana Benítez‐López
- Department of Environmental ScienceInstitute for Water and Wetland ResearchRadboud UniversityNijmegenthe Netherlands
- Integrative Ecology GroupEstación Biológica de Doñana (EBD‐CSIC)SevillaSpain
| | - Aafke M. Schipper
- Department of Environmental ScienceInstitute for Water and Wetland ResearchRadboud UniversityNijmegenthe Netherlands
- PBL Netherlands Environmental Assessment AgencyThe Haguethe Netherlands
| | - Wilfried Thuiller
- Université Grenoble Alpes, CNRS, University of Savoie Mont BlancLECA, Laboratoire d’Écologie AlpineGrenobleFrance
| | - Madhur Anand
- School of Environmental SciencesUniversity of GuelphGuelphOntarioCanada
| | | | | | - Andres Gonzalez‐Melo
- Facultad de Ciencias Naturales y MatemáticasUniversidad del RosarioBogotaColombia
| | - Wesley N. Hattingh
- School of Animal, Plant and Environmental SciencesUniversity of the WitwatersrandJohannesburgSouth Africa
| | - Pedro Higuchi
- Forestry DepartmentSanta Catarina State UniversityLagesBrazil
| | | | | | - Josep Peñuelas
- CREAF, VallèsCataloniaSpain
- CSIC, Global Ecology Unit CREAF‐CEAB‐UABCataloniaSpain
| | - Lourens Poorter
- Forest Ecology and Forest Management GroupWageningen University and ResearchWageningenthe Netherlands
| | - Nadejda A. Soudzilovskaia
- Environmental Biology DepartmentInstitute of Environmental SciencesLeiden UniversityLeidenthe Netherlands
| | - Mark A. J. Huijbregts
- Department of Environmental ScienceInstitute for Water and Wetland ResearchRadboud UniversityNijmegenthe Netherlands
| | - Luca Santini
- Department of Environmental ScienceInstitute for Water and Wetland ResearchRadboud UniversityNijmegenthe Netherlands
- National Research CouncilInstitute of Research on Terrestrial Ecosystems (CNR‐IRET)MonterotondoItaly
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18
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LaForgia ML, Harrison SP, Latimer AM. Invasive species interact with climatic variability to reduce success of natives. Ecology 2020; 101:e03022. [PMID: 32083742 DOI: 10.1002/ecy.3022] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 12/16/2019] [Accepted: 01/23/2020] [Indexed: 11/11/2022]
Abstract
Plants have evolved resource-conservative and resource-acquisitive strategies to deal with variability in rainfall, but interactions with dominant invasive species may undermine these adaptations. To investigate the relative effect of invaders on species with these two strategies, we manipulated rainfall and invasive grass presence and measured demographic rates in three resource-acquisitive and three resource-conservative native annual forbs. We found that invasive grasses were harmful to all of the target species, but especially the resource-acquisitive ones, and that these effects were stronger under experimental drought. Invasive grass presence under drought lowered per capita population growth rates of acquisitive natives through increased mortality and decreased seed set. While invasive grasses also decreased per capita growth rates of resource-conservative natives, they did so by increasing mortality under experimental watering and by limiting the production of seed under experimental drought. Invasive species can thus interact with climatic fluctuations to make bad years worse for resource-acquisitive natives and good years less good for resource-conservative natives, and they may generally tend to undermine the acquisitive strategy more than the conservative one.
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Affiliation(s)
- Marina L LaForgia
- Department of Plant Sciences, University of California, Davis, One Shields Avenue, Davis, California, USA
| | - Susan P Harrison
- Department of Environmental Science and Policy, University of California, Davis, One Shields Avenue, Davis, California, USA
| | - Andrew M Latimer
- Department of Plant Sciences, University of California, Davis, One Shields Avenue, Davis, California, USA
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19
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Salmela MJ, Velmala SM, Pennanen T. Seedling traits from root to shoot exhibit genetic diversity and distinct responses to environmental heterogeneity within a tree population. OIKOS 2020. [DOI: 10.1111/oik.06797] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Matti J. Salmela
- Natural Resources Inst. Finland (Luke) Latokartanonkaari 9 FI‐00790 Helsinki Finland
| | - Sannakajsa M. Velmala
- Natural Resources Inst. Finland (Luke) Latokartanonkaari 9 FI‐00790 Helsinki Finland
| | - Taina Pennanen
- Natural Resources Inst. Finland (Luke) Latokartanonkaari 9 FI‐00790 Helsinki Finland
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20
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Wang YL, Li XR, Zhao JC, Liu LC, Yang HT, Zhou YY. Population dynamics of Echinops gmelinii Turcz. at different successional stages of biological soil crusts in a temperate desert in China. PLANT BIOLOGY (STUTTGART, GERMANY) 2019; 21:1140-1149. [PMID: 31271693 DOI: 10.1111/plb.13027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 06/28/2019] [Indexed: 06/09/2023]
Abstract
The effects of biological soil crusts (BSC) on vascular plant growth can be positive, neutral or negative, and little information is available on the impacts of different BSC successional stages on vascular plant population dynamics. We analysed seedling emergence, survival, plant growth and reproduction in response to different BSC successional stages (i.e. habitats: bare soil, cyanobacteria, lichen and moss crusts) in natural populations of Echinops gmelinii Turcz. in the Tengger Desert of northwest China. The winter annual E. gmelinii is a dominant pioneer herb after sand stabilisation. During the early stages of BSC succession, the studied populations of E. gmelinii were characterised by high density, plant growth and fecundity. As the BSC succession proceeded beyond moss crusts, the fecundity decreased sharply, which limited seedling recruitment. Differences in seedling survival among the successional stages were not evident, indicating that BSC have little effect on survival in arid desert regions. Moreover, E. gmelinii biomass allocation exhibited low plasticity, and only reproductive allocation was sensitive to the various habitats. Our results further suggest that the negative effects of BSC succession on population dynamics are primarily driven by increasing topsoil water-holding capacity and decreasing rain water infiltration into deeper soil. We conclude that BSC succession drives population dynamics of E. gmelinii, primarily via its effect on soil moisture. The primary cause for E. gmelinii population decline during the moss-dominated stage of BSC succession is decreased fecundity of individual plants, with declining seed mass possibly reducing the success of seedling establishment.
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Affiliation(s)
- Y L Wang
- Shapotou Desert Research and Experimental Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu, China
- University of Chinese Academy of Sciences, Beijing, China
| | - X R Li
- Shapotou Desert Research and Experimental Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu, China
| | - J C Zhao
- Shapotou Desert Research and Experimental Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu, China
| | - L C Liu
- Shapotou Desert Research and Experimental Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu, China
| | - H T Yang
- Shapotou Desert Research and Experimental Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu, China
| | - Y Y Zhou
- Shapotou Desert Research and Experimental Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu, China
- University of Chinese Academy of Sciences, Beijing, China
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21
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Harrison S, LaForgia M. Seedling traits predict drought-induced mortality linked to diversity loss. Proc Natl Acad Sci U S A 2019; 116:5576-5581. [PMID: 30833396 PMCID: PMC6431227 DOI: 10.1073/pnas.1818543116] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Trait-based approaches are increasingly used to predict ecological consequences of climate change, yet seldom have solid links been established between plant traits and observed climate-driven community changes. Most analyses have focused on aboveground adult plant traits, but in warming and drying climates, root traits may be critical, and seedlings may be the vulnerable stage. Relationships of seedling and root traits to more commonly measured traits and ecological outcomes are poorly known. In an annual grassland where winter drought-induced seedling mortality is driving a long-term decline in native diversity, using a field experiment during the exceptionally dry winter of 2017-2018, we found that seedling mortality was higher and growth of seedlings and adults were lower in unwatered than watered sites. Mortality of unwatered seedlings was higher in species with shorter seedling roots, and also in species with the correlated traits of small seeds, high seedling specific leaf area (SLA), and tall seedlings. Adult traits varied along an axis from short-stature, high SLA and foliar N, and early flowering to the opposite values, and were only weakly correlated with seedling traits and seedling mortality. No evidence was found for adaptive plasticity, such as longer roots or lower SLA in unwatered plants. Among these species, constitutive variation in seedling root length explained most of the variation in survival of a highly vulnerable life stage under winter drought. Selective loss of species with high adult SLA, observed in this community and others under drought stress, may be the byproduct of other correlated traits.
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Affiliation(s)
- Susan Harrison
- Department of Environmental Science and Policy, University of California, Davis, CA 95616;
| | - Marina LaForgia
- Department of Plant Sciences, University of California, Davis, CA 95616
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22
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Ge XM, Scholl JP, Basinger U, Huxman TE, Venable DL. Functional trait trade‐off and species abundance: insights from a multi‐decadal study. Ecol Lett 2019; 22:583-592. [DOI: 10.1111/ele.13217] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 11/18/2018] [Accepted: 12/10/2018] [Indexed: 01/20/2023]
Affiliation(s)
- Xing‐Yue M. Ge
- Department of Ecology and Evolutionary Biology University of Arizona Tucson AZ85721USA
| | - Joshua P. Scholl
- Department of Ecology and Evolutionary Biology University of Arizona Tucson AZ85721USA
| | - Ursula Basinger
- Department of Ecology and Evolutionary Biology University of Arizona Tucson AZ85721USA
| | - Travis E. Huxman
- Department of Ecology and Evolutionary Biology University of California Irvine CA92697 USA
| | - D. Lawrence Venable
- Department of Ecology and Evolutionary Biology University of Arizona Tucson AZ85721USA
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23
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Cuello WS, Gremer JR, Trimmer PC, Sih A, Schreiber SJ. Predicting evolutionarily stable strategies from functional responses of Sonoran Desert annuals to precipitation. Proc Biol Sci 2019; 286:20182613. [PMID: 30963878 PMCID: PMC6367162 DOI: 10.1098/rspb.2018.2613] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 12/18/2018] [Indexed: 11/12/2022] Open
Abstract
For many decades, researchers have studied how plants use bet-hedging strategies to insure against unpredictable, unfavourable conditions. We improve upon earlier analyses by explicitly accounting for how variable precipitation affects annual plant species' bet-hedging strategies. We consider how the survival rates of dormant seeds (in a 'seed bank') interact with precipitation responses to influence optimal germination strategies. Specifically, we incorporate how response to resource availability (i.e. the amount of offspring (seeds) generated per plant in response to variation in desert rainfall) influences the evolution of germination fractions. Using data from 10 Sonoran Desert annual plants, we develop models that explicitly include these responses to model fitness as a function of precipitation. For each of the species, we identify the predicted evolutionarily stable strategies (ESSs) for the fraction of seeds germinating each year and then compare our estimated ESS values to the observed germination fractions. We also explore the relative importance of seed survival and precipitation responses in shaping germination strategies by regressing ESS values and observed germination fractions against these traits. We find that germination fractions are lower for species with higher seed survival, with lower reproductive success in dry years, and with better yield responses in wet years. These results illuminate the evolution of bet-hedging strategies in an iconic system, and provide a framework for predicting how current and future environmental conditions may reshape those strategies.
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Affiliation(s)
- William S. Cuello
- PhD Program in Applied Mathematics, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - Jennifer R. Gremer
- Department of Evolution and Ecology, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - Pete C. Trimmer
- Department of Environmental Science and Policy, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - Andrew Sih
- Department of Environmental Science and Policy, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - Sebastian J. Schreiber
- Department of Evolution and Ecology, University of California, 1 Shields Avenue, Davis, CA 95616, USA
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24
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Liberati D, de Dato G, Guidolotti G, De Angelis P. Linking photosynthetic performances with the changes in cover degree of three Mediterranean shrubs under climate manipulation. OIKOS 2018. [DOI: 10.1111/oik.05263] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dario Liberati
- Dept for Innovation in Biological, Agro-Food and Forest Systems (DIBAF); Univ. of Tuscia; Viterbo Italy
| | - Giovanbattista de Dato
- Council for Agricultural Research and Economics (CREA); Research Centre for Forestry and Wood; Arezzo Italy
| | - Gabriele Guidolotti
- Dept for Innovation in Biological, Agro-Food and Forest Systems (DIBAF); Univ. of Tuscia; Viterbo Italy
- Inst. for Agro-Environment and Forest Biology (IBAF); National Research Council of Italy (CNR); Porano (TR) Italy
| | - Paolo De Angelis
- Dept for Innovation in Biological, Agro-Food and Forest Systems (DIBAF); Univ. of Tuscia; Viterbo Italy
- Div. of Impact Studies and Physiological Analyses; Global Change Research Centre; Brno Czech Republic
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25
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Madliger CL, Love OP, Hultine KR, Cooke SJ. The conservation physiology toolbox: status and opportunities. CONSERVATION PHYSIOLOGY 2018; 6:coy029. [PMID: 29942517 PMCID: PMC6007632 DOI: 10.1093/conphys/coy029] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 05/18/2018] [Accepted: 05/24/2018] [Indexed: 05/21/2023]
Abstract
For over a century, physiological tools and techniques have been allowing researchers to characterize how organisms respond to changes in their natural environment and how they interact with human activities or infrastructure. Over time, many of these techniques have become part of the conservation physiology toolbox, which is used to monitor, predict, conserve, and restore plant and animal populations under threat. Here, we provide a summary of the tools that currently comprise the conservation physiology toolbox. By assessing patterns in articles that have been published in 'Conservation Physiology' over the past 5 years that focus on introducing, refining and validating tools, we provide an overview of where researchers are placing emphasis in terms of taxa and physiological sub-disciplines. Although there is certainly diversity across the toolbox, metrics of stress physiology (particularly glucocorticoids) and studies focusing on mammals have garnered the greatest attention, with both comprising the majority of publications (>45%). We also summarize the types of validations that are actively being completed, including those related to logistics (sample collection, storage and processing), interpretation of variation in physiological traits and relevance for conservation science. Finally, we provide recommendations for future tool refinement, with suggestions for: (i) improving our understanding of the applicability of glucocorticoid physiology; (ii) linking multiple physiological and non-physiological tools; (iii) establishing a framework for plant conservation physiology; (iv) assessing links between environmental disturbance, physiology and fitness; (v) appreciating opportunities for validations in under-represented taxa; and (vi) emphasizing tool validation as a core component of research programmes. Overall, we are confident that conservation physiology will continue to increase its applicability to more taxa, develop more non-invasive techniques, delineate where limitations exist, and identify the contexts necessary for interpretation in captivity and the wild.
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Affiliation(s)
- Christine L Madliger
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, 1125 Colonel By Dr., Ottawa, Ontario, Canada
- Department of Biological Sciences, University of Windsor, 401 Sunset Ave., Ontario, Canada
| | - Oliver P Love
- Department of Biological Sciences, University of Windsor, 401 Sunset Ave., Ontario, Canada
| | - Kevin R Hultine
- Department of Research, Conservation and Collections, Desert Botanical Garden, 1201 N. Galvin Parkway, Phoenix, AZ, USA
| | - Steven J Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, 1125 Colonel By Dr., Ottawa, Ontario, Canada
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Harrison SP, LaForgia ML, Latimer AM. Climate-driven diversity change in annual grasslands: Drought plus deluge does not equal normal. GLOBAL CHANGE BIOLOGY 2018; 24:1782-1792. [PMID: 29244898 DOI: 10.1111/gcb.14018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 11/07/2017] [Accepted: 12/07/2017] [Indexed: 06/07/2023]
Abstract
Climate forecasts agree that increased variability and extremes will tend to reduce the availability of water in many terrestrial ecosystems. Increasingly severe droughts may be exacerbated both by warmer temperatures and by the relative unavailability of water that arrives in more sporadic and intense rainfall events. Using long-term data and an experimental water manipulation, we examined the resilience of a heterogeneous annual grassland community to a prolonged series of dry winters that led to a decline in plant species richness (2000-2014), followed by a near-record wet winter (2016-2017), a climatic sequence that broadly resembles the predicted future in its high variability. In our 80, 5-m2 observational plots, species richness did not recover in response to the wet winter, and the positive relationship of richness to annual winter rainfall thus showed a significant weakening trend over the 18-year time period. In experiments on 100, 1-m2 plots, wintertime water supplementation increased and drought shelters decreased the seedling survival and final individual biomass of native annual forbs, the main functional group contributing to the observed long-term decline in richness. Water supplementation also increased the total cover of native annual forbs, but only increased richness within nested subplots to which seeds were also added. We conclude that prolonged dry winters, by increasing seedling mortality and reducing growth of native forbs, may have diminished the seedbank and thus the recovery potential of diversity in this community. However, the wet winter and the watering treatment did cause recovery of the community mean values of a key functional trait (specific leaf area, an indicator of drought intolerance), suggesting that some aggregate community properties may be stabilized by functional redundancy among species.
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Affiliation(s)
- Susan P Harrison
- Department of Environmental Science and Policy, University of California, Davis, CA, USA
| | - Marina L LaForgia
- Department of Plant Sciences, University of California, Davis, CA, USA
| | - Andrew M Latimer
- Department of Plant Sciences, University of California, Davis, CA, USA
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27
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LaForgia ML, Spasojevic MJ, Case EJ, Latimer AM, Harrison SP. Seed banks of native forbs, but not exotic grasses, increase during extreme drought. Ecology 2018; 99:896-903. [PMID: 29494753 DOI: 10.1002/ecy.2160] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 12/23/2017] [Accepted: 01/08/2018] [Indexed: 11/06/2022]
Abstract
Extreme droughts such as the one that affected California in 2012-2015 have been linked to severe ecological consequences in perennial-dominated communities such as forests. In annual communities, drought impacts are difficult to assess because many species persist through facultative multiyear seed dormancy, which leads to the development of seed banks. Impacts of extreme drought on the abundance and composition of the seed banks of whole communities are little known. In 80 heterogeneous grassland plots where cover is dominated by ~15 species of exotic annual grasses and diversity is dominated by ~70 species of native annual forbs, we grew out seeds from soil cores collected early in the California drought (2012) and later in the multiyear drought (2014), and analyzed drought-associated changes in the seed bank. Over the course of the study we identified more than 22,000 seedlings to species. We found that seeds of exotic annual grasses declined sharply in abundance during the drought while seeds of native annual forbs increased, a pattern that resembled but was even stronger than the changes in aboveground cover of these groups. Consistent with the expectation that low specific leaf area (SLA) is an indicator of drought tolerance, we found that the community-weighted mean SLA of annual forbs declined both in the seed bank and in the aboveground community, as low-SLA forbs increased disproportionately. In this system, seed dormancy reinforces the indirect benefits of extreme drought to the native forb community.
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Affiliation(s)
- Marina L LaForgia
- Department of Plant Sciences, University of California, One Shields Ave, Davis, California, 95616, USA
| | - Marko J Spasojevic
- Department of Evolution, Ecology, and Organismal Biology, University of California, 900 University Ave, Riverside, California, 92521, USA
| | - Erica J Case
- Department of Land, Air and Water Resources, University of California, One Shields Ave, Davis, California, 95616, USA
| | - Andrew M Latimer
- Department of Plant Sciences, University of California, One Shields Ave, Davis, California, 95616, USA
| | - Susan P Harrison
- Department of Environmental Science and Policy, University of California, 900 University Ave, Davis, California, 92521, USA
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28
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Granda E, Alla AQ, Laskurain NA, Loidi J, Sánchez-Lorenzo A, Camarero JJ. Coexisting oak species, including rear-edge populations, buffer climate stress through xylem adjustments. TREE PHYSIOLOGY 2018; 38:159-172. [PMID: 29300954 DOI: 10.1093/treephys/tpx157] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 11/17/2017] [Indexed: 05/12/2023]
Abstract
The ability of trees to cope with climate change is a pivotal feature of forest ecosystems, especially for rear-edge populations facing warm and dry conditions. To evaluate current and future forests threats, a multi-proxy focus on the growth, anatomical and physiological responses to climate change is needed. We examined the long-term xylem adjustments to climate variability of the temperate Quercus robur L. at its rear edge and the sub-Mediterranean Quercus pyrenaica Willd. Both species coexist at a mesic (ME, humid and warmer) and a xeric (XE, dry and cooler) site in northern Spain, the latter experiencing increasing temperatures in recent decades. We compared xylem traits at each site and assessed their trends, relationships and responses to climate (1960-2008). Traits included basal area increment, earlywood vessel hydraulic diameter, density and theoretical-specific hydraulic conductivity together with latewood oxygen (δ18O) stable isotopes and δ13C-derived water-use efficiency (iWUE). Quercus robur showed the highest growth at ME, likely through enhanced cambial activity. Quercus pyrenaica had higher iWUE at XE compared with ME, but limited plasticity of anatomical xylem traits was found for the two oak species. Similar physiological performance was found for both species. The iWUE augmented in recent years especially at XE, likely explained by stomatal closure given the increasing δ18O signal in response to drier and sunnier growing seasons. Overall, traits were more correlated at XE than at ME. The iWUE improvements were linked to higher growth up to a threshold (~85 μmol mol-1) after which reduced growth was found at XE. Our results are consistent with Q. pyrenaica and Q. robur coexisting at the central and dry edge of the climatic species distribution, respectively, showing similar responses to buffer warmer conditions. In fact, the observed adjustments found for Q. robur point towards growth stability of similar rear-edge oak populations under warmer climate conditions.
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Affiliation(s)
- E Granda
- Instituto Pirenaico de Ecología (IPE-CSIC), Avenida Montañana 1005, 50080 Zaragoza, Spain
| | - A Q Alla
- Fakulteti i Shkencave Pyjore, Universiteti Bujqësor i Tiranës, Kodër-Kamëz 1029, Tirana, Albania
| | - N A Laskurain
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
| | - J Loidi
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
| | - A Sánchez-Lorenzo
- Instituto Pirenaico de Ecología (IPE-CSIC), Avenida Montañana 1005, 50080 Zaragoza, Spain
| | - J J Camarero
- Instituto Pirenaico de Ecología (IPE-CSIC), Avenida Montañana 1005, 50080 Zaragoza, Spain
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Myers-Smith IH, Myers JH. Comment on "Precipitation drives global variation in natural selection". Science 2018; 359:359/6374/eaan5028. [PMID: 29371441 DOI: 10.1126/science.aan5028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Accepted: 08/18/2017] [Indexed: 11/02/2022]
Abstract
Siepielski et al (Reports, 3 March 2017, p. 959) claim that "precipitation drives global variation in natural selection." This conclusion is based on a meta-analysis of the relationship between climate variables and natural selection measured in wild populations of invertebrates, plants, and vertebrates. Three aspects of this analysis cause concern: (i) lack of within-year climate variables, (ii) low and variable estimates of covariance relationships across taxa, and (iii) a lack of mechanistic explanations for the patterns observed; association is not causation.
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Affiliation(s)
| | - Judith H Myers
- Biodiversity Research Centre, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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30
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Scopece G, Juillet N, Lexer C, Cozzolino S. Fluctuating selection across years and phenotypic variation in food-deceptive orchids. PeerJ 2017; 5:e3704. [PMID: 28852594 PMCID: PMC5572944 DOI: 10.7717/peerj.3704] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 07/27/2017] [Indexed: 11/20/2022] Open
Abstract
Nectarless flowers that deceive pollinators offer an opportunity to study asymmetric plant-insect interactions. Orchids are a widely used model for studying these interactions because they encompass several thousand species adopting deceptive pollination systems. High levels of intra-specific phenotypic variation have been reported in deceptive orchids, suggesting a reduced consistency of pollinator-mediated selection on their floral traits. Nevertheless, several studies report on widespread directional selection mediated by pollinators even in these deceptive orchids. In this study we test the hypothesis that the observed selection can fluctuate across years in strength and direction thus likely contributing to the phenotypic variability of this orchid group. We performed a three-year study estimating selection differentials and selection gradients for nine phenotypic traits involved in insect attraction in two Mediterranean orchid species, namely Orchis mascula and O. pauciflora, both relying on a well-described food-deceptive pollination strategy. We found weak directional selection and marginally significant selection gradients in the two investigated species with significant intra-specific differences in selection differentials across years. Our data do not link this variation with a specific environmental cause, but our results suggest that pollinator-mediated selection in food-deceptive orchids can change in strength and in direction over time. In perennial plants, such as orchids, different selection differentials in the same populations in different flowering seasons can contribute to the maintenance of phenotypic variation often reported in deceptive orchids.
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Affiliation(s)
- Giovanni Scopece
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Nicolas Juillet
- UMR Peuplements Végétaux et Bioagresseurs en Milieu Tropical, Université de la Réunion, Pôle de Protection des Plantes, Saint Pierre, La Réunion, France
| | - Christian Lexer
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
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31
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Kimball S, E Lulow M, R Balazs K, Huxman TE. Predicting drought tolerance from slope aspect preference in restored plant communities. Ecol Evol 2017; 7:3123-3131. [PMID: 28480011 PMCID: PMC5415533 DOI: 10.1002/ece3.2881] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 01/19/2017] [Accepted: 02/07/2017] [Indexed: 02/06/2023] Open
Abstract
Plants employ strategies of tolerance, endurance, and avoidance to cope with aridity in space and time, yet understanding the differential importance of such strategies in determining patterns of abundance across a heterogeneous landscape is a challenge. Are the species abundant in drier microhabitats also better able to survive drought? Are there relationships among occupied sites and temporal dynamics that derive from physiological capacities to cope with stress or dormancy during unfavorable periods? We used a restoration project conducted on two slope aspects in a subwatershed to test whether species that were more abundant on more water‐limited S‐facing slopes were also better able to survive an extreme drought. The attempt to place many species uniformly on different slope aspects provided an excellent opportunity to test questions of growth strategy, niche preference, and temporal dynamics. Perennial species that established and grew best on S‐facing slopes also had greater increases in cover during years of drought, presumably by employing drought tolerance and endurance techniques. The opposite pattern emerged for annual species that employed drought‐escape strategies, such that annuals that occupied S‐facing slopes were less abundant during the drought than those that were more abundant on N‐facing slopes. Our results clarify how different functional strategies interact with spatial and temporal heterogeneity to influence population and community dynamics and demonstrate how large restoration projects provide opportunities to test fundamental ecological questions.
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Affiliation(s)
- Sarah Kimball
- Center for Environmental Biology University of California Irvine CA 92697-1450 USA
| | | | | | - Travis E Huxman
- Center for Environmental Biology and Department of Ecology and Evolutionary Biology University of California, Irvine Irvine CA USA
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32
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Rull V, Vegas-Vilarrúbia T. Potential Responses of Vascular Plants from the Pristine "Lost World" of the Neotropical Guayana Highlands to Global Warming: Review and New Perspectives. FRONTIERS IN PLANT SCIENCE 2017; 8:81. [PMID: 28179913 PMCID: PMC5263137 DOI: 10.3389/fpls.2017.00081] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 01/13/2017] [Indexed: 06/06/2023]
Abstract
The neotropical Guayana Highlands (GH) are one of the few remaining pristine environments on Earth, and they host amazing biodiversity with a high degree endemism, especially among vascular plants. Despite the lack of direct human disturbance, GH plants and their communities are threatened with extinction from habitat loss due to global warming (GW). Geographic information systems simulations involving the entire known vascular GH flora (>2430 species) predict potential GW-driven extinctions on the order of 80% by the end of this century, including nearly half of the endemic species. These estimates and the assessment of an environmental impact value for each species led to the hierarchization of plants by their risk of habitat loss and the definition of priority conservation categories. However, the predictions assume that all species will respond to GW by migrating upward and at equal rates, which is unlikely, so current estimates should be considered preliminary and incomplete (although they represent the best that can be done with the existing information). Other potential environmental forcings (i.e., precipitation shifts, an increase in the atmospheric CO2 concentration) and idiosyncratic plant responses (i.e., resistance, phenotypic acclimation, rapid evolution) should also be considered, so detailed eco-physiological studies of the more threatened species are urgently needed. The main obstacles to developing such studies are the remoteness and inaccessibility of the GH and, especially, the difficulty in obtaining official permits for fieldwork.
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Affiliation(s)
- Valentí Rull
- Institute of Earth Sciences Jaume Almera (ICTJA-CSIC)Barcelona, Spain
| | - Teresa Vegas-Vilarrúbia
- Department of Evolutionary Biology, Ecology and Environmental Sciences, Universitat de BarcelonaBarcelona, Spain
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33
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Muscarella R, Uriarte M. Do community-weighted mean functional traits reflect optimal strategies? Proc Biol Sci 2016; 283:20152434. [PMID: 27030412 DOI: 10.1098/rspb.2015.2434] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Accepted: 03/01/2016] [Indexed: 11/12/2022] Open
Abstract
The notion that relationships between community-weighted mean (CWM) traits (i.e. plot-level trait values weighted by species abundances) and environmental conditions reflect selection towards locally optimal phenotypes is challenged by the large amount of interspecific trait variation typically found within ecological communities. Reconciling these contrasting patterns is a key to advancing predictive theories of functional community ecology. We combined data on geographical distributions and three traits (wood density, leaf mass per area and maximum height) of 173 tree species in Puerto Rico. We tested the hypothesis that species are more likely to occur where their trait values are more similar to the local CWM trait values (the'CWM-optimality' hypothesis) by comparing species occurrence patterns (as a proxy for fitness) with the functional composition of forest plots across a precipitation gradient. While 70% of the species supported CWM-optimality for at least one trait, nearly 25% significantly opposed it for at least one trait, thereby contributing to local functional diversity. The majority (85%) of species that opposed CWM-optimality did so only for one trait and few species opposed CWM-optimality in multivariate trait space. Our study suggests that constraints to local functional variation act more strongly on multivariate phenotypes than on univariate traits.
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Affiliation(s)
- Robert Muscarella
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY 10027, USA Section for Ecoinformatics and Biodiversity, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark
| | - María Uriarte
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY 10027, USA
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34
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Madliger CL, Love OP. The Power of Physiology in Changing Landscapes: Considerations for the Continued Integration of Conservation and Physiology. Integr Comp Biol 2016; 55:545-53. [PMID: 25805172 DOI: 10.1093/icb/icv001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The growing field of conservation physiology applies a diversity of physiological traits (e.g., immunological, metabolic, endocrine, and nutritional traits) to understand and predict organismal, population, and ecosystem responses to environmental change and stressors. Although the discipline of conservation physiology is gaining momentum, there is still a pressing need to better translate knowledge from physiology into real-world tools. The goal of this symposium, ‘‘Physiology in Changing Landscapes: An Integrative Perspective for Conservation Biology’’, was to highlight that many current investigations in ecological, evolutionary, and comparative physiology are necessary for understanding the applicability of physiological measures for conservation goals, particularly in the context of monitoring and predicting the health, condition, persistence, and distribution of populations in the face of environmental change. Here, we outline five major investigations common to environmental and ecological physiology that can contribute directly to the progression of the field of conservation physiology: (1) combining multiple measures of physiology and behavior; (2) employing studies of dose–responses and gradients; (3) combining a within-individual and population-level approach; (4) taking into account the context-dependency of physiological traits; and (5) linking physiological variables with fitness metrics. Overall, integrative physiologists have detailed knowledge of the physiological systems that they study; however, communicating theoretical and empirical knowledge to conservation biologists and practitioners in an approachable and applicable way is paramount to the practical development of physiological tools that will have a tangible impact for conservation.
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Gremer JR, Kimball S, Venable DL. Within‐and among‐year germination in Sonoran Desert winter annuals: bet hedging and predictive germination in a variable environment. Ecol Lett 2016; 19:1209-18. [DOI: 10.1111/ele.12655] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 06/07/2016] [Accepted: 07/03/2016] [Indexed: 01/11/2023]
Affiliation(s)
- Jennifer R. Gremer
- Department of Evolution and Ecology University of California Davis CA95616 USA
| | - Sarah Kimball
- Center for Environmental Biology University of California Irvine CA92697 USA
| | - D. Lawrence Venable
- Department Ecology and Evolutionary Biology University of Arizona Tucson AZ85721 USA
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36
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Huang Z, Liu S, Bradford KJ, Huxman TE, Venable DL. The contribution of germination functional traits to population dynamics of a desert plant community. Ecology 2016; 97:250-61. [PMID: 27008793 DOI: 10.1890/15-0744.1] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Early life-cycle events play critical roles in determining the population and community dynamics of plants. The ecology of seeds and their germination patterns can determine range limits, adaptation to environmental variation, species diversity, and community responses to climate change. Understanding the adaptive consequences and environmental filtering of such functional traits will allow us to explain and predict ecological dynamics. Here we quantify key functional aspects of germination physiology and relate them to an existing functional ecology framework to explain long-term population dynamics for 13 species of desert annuals near Tucson, Arizona, USA. Our goal was to assess the extent to which germination functional biology contributes to long-term population processes in nature. Some of the species differences in base, optimum, and maximum temperatures for germination, thermal times to germination, and base water potentials for germination were strongly related to 20-yr mean germination fractions, 25-yr average germination dates, seed size, and long-term demographic variation. Comparisons of germination fraction, survival, and fecundity vs. yearly changes in population size found significant roles for all three factors, although in varying proportions for different species. Relationships between species' germination physiologies and relative germination fractions varied across years, with fast-germinating species being favored in years with warm temperatures during rainfall events in the germination season. Species with low germination fractions and high demographic variance have low integrated water-use efficiency, higher vegetative growth rates, and smaller, slower-germinating seeds. We have identified and quantified a number of functional traits associated with germination biology that play critical roles in ecological population dynamics.
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37
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Laughlin DC, Strahan RT, Huffman DW, Sánchez Meador AJ. Using trait‐based ecology to restore resilient ecosystems: historical conditions and the future of montane forests in western North America. Restor Ecol 2016. [DOI: 10.1111/rec.12342] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Daniel C. Laughlin
- Environmental Research Institute and School of Science University of Waikato Private Bag 3105 Hamilton 3240 New Zealand
- School of Forestry Northern Arizona University PO Box 15018 Flagstaff AZ 86011 U.S.A
| | - Robert T. Strahan
- New Mexico Forest and Watershed Restoration Institute New Mexico Highlands University PO Box 9000 Las Vegas NM 87701 U.S.A
| | - David W. Huffman
- Ecological Restoration Institute Northern Arizona University PO Box 15017 Flagstaff AZ 86011 U.S.A
| | - Andrew J. Sánchez Meador
- School of Forestry Northern Arizona University PO Box 15018 Flagstaff AZ 86011 U.S.A
- Ecological Restoration Institute Northern Arizona University PO Box 15017 Flagstaff AZ 86011 U.S.A
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38
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Kimball S, Lulow M, Sorenson Q, Balazs K, Fang YC, Davis SJ, O'Connell M, Huxman TE. Cost-effective ecological restoration. Restor Ecol 2015. [DOI: 10.1111/rec.12261] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sarah Kimball
- Center for Environmental Biology; University of California, Irvine; Irvine CA 92697-1450 U.S.A
| | - Megan Lulow
- Center for Environmental Biology; University of California, Irvine; Irvine CA 92697-1450 U.S.A
- Irvine Ranch Conservancy; Irvine CA 92620 U.S.A
| | | | - Kathleen Balazs
- Center for Environmental Biology; University of California, Irvine; Irvine CA 92697-1450 U.S.A
- Irvine Ranch Conservancy; Irvine CA 92620 U.S.A
| | | | - Steven J. Davis
- Department of Earth System Science; University of California, Irvine; Croul Hall Irvine CA 92697 U.S.A
| | | | - Travis E. Huxman
- Center for Environmental Biology; University of California, Irvine; Irvine CA 92697-1450 U.S.A
- Department of Ecology and Evolutionary Biology; University of California, Irvine; Steinhaus Hall Irvine CA 92697 U.S.A
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39
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Harrison SP, Gornish ES, Copeland S. Climate-driven diversity loss in a grassland community. Proc Natl Acad Sci U S A 2015; 112:8672-7. [PMID: 26100891 PMCID: PMC4507231 DOI: 10.1073/pnas.1502074112] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Local ecological communities represent the scale at which species coexist and share resources, and at which diversity has been experimentally shown to underlie stability, productivity, invasion resistance, and other desirable community properties. Globally, community diversity shows a mixture of increases and decreases over recent decades, and these changes have relatively seldom been linked to climatic trends. In a heterogeneous California grassland, we documented declining plant diversity from 2000 to 2014 at both the local community (5 m(2)) and landscape (27 km(2)) scales, across multiple functional groups and soil environments. Communities became particularly poorer in native annual forbs, which are present as small seedlings in midwinter; within native annual forbs, community composition changed toward lower representation of species with a trait indicating drought intolerance (high specific leaf area). Time series models linked diversity decline to the significant decrease in midwinter precipitation. Livestock grazing history, fire, succession, N deposition, and increases in exotic species could be ruled out as contributing causes. This finding is among the first demonstrations to our knowledge of climate-driven directional loss of species diversity in ecological communities in a natural (nonexperimental) setting. Such diversity losses, which may also foreshadow larger-scale extinctions, may be especially likely in semiarid regions that are undergoing climatic trends toward higher aridity and lower productivity.
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Affiliation(s)
- Susan P Harrison
- Department of Environmental Science and Policy, University of California, Davis, CA 95616;
| | - Elise S Gornish
- Department of Plant Sciences, University of California, Davis, CA 95616
| | - Stella Copeland
- Department of Environmental Science and Policy, University of California, Davis, CA 95616
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40
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Angert AL, Kimball S, Peterson M, Huxman TE, Venable DL. Phenotypic constraints and community structure: Linking trade-offs within and among species. Evolution 2014; 68:3149-65. [DOI: 10.1111/evo.12514] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 07/29/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Amy L. Angert
- Departments of Botany and Zoology; University of British Columbia; Vancouver BC V6T 1Z4 Canada
| | - Sarah Kimball
- Center for Environmental Biology; University of California; Irvine California 92697
| | - Megan Peterson
- Department of Ecology and Evolutionary Biology; University of California; Santa Cruz California 95064
| | - Travis E. Huxman
- Center for Environmental Biology; University of California; Irvine California 92697
- Department of Ecology and Evolutionary Biology; University of California; Irvine California 92697
| | - David L. Venable
- Department of Ecology and Evolutionary Biology; University of Arizona; Tucson Arizona 85721
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41
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Letten AD, Cornwell WK. Trees, branches and (square) roots: why evolutionary relatedness is not linearly related to functional distance. Methods Ecol Evol 2014. [DOI: 10.1111/2041-210x.12237] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Andrew D. Letten
- Centre for Ecosystem Science School of Biological, Earth and Environmental Sciences UNSW Sydney NSW 2052Australia
| | - William K. Cornwell
- Evolution and Ecology Research Centre School of Biological, Earth and Environmental Sciences UNSW Sydney NSW 2052 Australia
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42
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Gremer JR, Venable DL. Bet hedging in desert winter annual plants: optimal germination strategies in a variable environment. Ecol Lett 2014; 17:380-7. [DOI: 10.1111/ele.12241] [Citation(s) in RCA: 204] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 11/11/2013] [Accepted: 11/28/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Jennifer R. Gremer
- Department of Ecology and Evolutionary Biology; University of Arizona; Tucson AZ 85721 USA
| | - D. Lawrence Venable
- Department of Ecology and Evolutionary Biology; University of Arizona; Tucson AZ 85721 USA
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43
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Kimball S, Gremer JR, Barron-Gafford GA, Angert AL, Huxman TE, Venable DL. High water-use efficiency and growth contribute to success of non-native Erodium cicutarium in a Sonoran Desert winter annual community. CONSERVATION PHYSIOLOGY 2014; 2:cou006. [PMID: 27293627 PMCID: PMC4806723 DOI: 10.1093/conphys/cou006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 01/16/2014] [Accepted: 01/20/2014] [Indexed: 05/03/2023]
Abstract
The success of non-native, invasive species may be due to release from natural enemies, superior competitive abilities, or both. In the Sonoran Desert, Erodium cicutarium has increased in abundance over the last 30 years. While native species in this flora exhibit a strong among-species trade-off between relative growth rate and water-use efficiency, E. cicutarium seems to have a higher relative growth rate for its water-use efficiency value relative to the pattern across native species. This novel trait combination could provide the non-native species with a competitive advantage in this water-limited environment. To test the hypothesis that E. cicutarium is able to achieve high growth rates due to release from native herbivores, we compared the effects of herbivory on E. cicutarium and its native congener, Erodium texanum. We also compared these two species across a range of environmental conditions, both in a common garden and in two distinct seasons in the field, using growth analysis, isotopic compositions and leaf-level gas exchange. Additionally, we compared the competitive abilities of the two Erodium species in a greenhouse experiment. We found no evidence of herbivory to either species. Physiological measurements in a common environment revealed that E. cicutarium was able to achieve high growth rates while simultaneously controlling leaf-level water loss. Non-native E. cicutarium responded to favourable conditions in the field with greater specific leaf area and leaf area ratio than native E. texanum. The non-native Erodium was a stronger competitor than its native congener in a greenhouse competition experiment. The ability to maintain relatively higher values of water-use efficiency:relative growth rate in comparison to the native flora may be what enables E. cictarium to outcompete native species in both wet and dry years, resulting in an increase in abundance in the highly variable Sonoran Desert.
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Affiliation(s)
- Sarah Kimball
- Center for Environmental Biology, University of California, Irvine, Irvine, CA 92697-1450, USA
- Corresponding author: BIO SCI – Center for Environmental Biology, University of California, Irvine, Irvine, CA 92697-1450, USA. Tel: +1 949 824 7151.
| | | | | | - Amy L. Angert
- Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
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44
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Zinnert JC, Shiflett SA, Vick JK, Young DR. Plant functional traits of a shrub invader relative to sympatric native shrubs. Ecosphere 2013. [DOI: 10.1890/es13-00111.1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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45
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Gremer JR, Kimball S, Keck KR, Huxman TE, Angert AL, Venable DL. Water-use efficiency and relative growth rate mediate competitive interactions in Sonoran Desert winter annual plants. AMERICAN JOURNAL OF BOTANY 2013; 100:2009-2015. [PMID: 24095798 DOI: 10.3732/ajb.1300064] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
PREMISE OF THE STUDY A functional approach to investigating competitive interactions can provide a mechanistic understanding of processes driving population dynamics, community assembly, and the maintenance of biodiversity. In Sonoran Desert annual plants, a trade-off between relative growth rate (RGR) and water-use efficiency (WUE) contributes to species differences in population dynamics that promote long-term coexistence. Traits underlying this trade-off explain variation in demographic responses to precipitation as well as life history and phenological patterns. Here, we ask how these traits mediate competitive interactions. • METHODS We conducted competition trials for three species occupying different positions along the RGR-WUE trade-off axis and compared the effects of competition at high and low soil moisture. We compared competitive effect (ability to suppress neighbors) and competitive response (ability to withstand competition from neighbors) among species. • KEY RESULTS The RGR-WUE trade-off predicted shifts in competitive responses at different soil moistures. The high-RGR species was more resistant to competition in high water conditions, while the opposite was true for the high-WUE species. The intermediate RGR species tended to have the strongest impact on all neighbors, so competitive effects did not scale directly with differences in RGR and WUE among competitors. • CONCLUSIONS Our results reveal mechanisms underlying long-term variation in fitness: high-RGR species perform better in years with large, frequent rain events and can better withstand competition under wetter conditions. The opposite is true for high-WUE species. Such resource-dependent responses strongly influence community dynamics and can promote coexistence in variable environments.
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Affiliation(s)
- Jennifer R Gremer
- Department of Ecology and Evolutionary Biology, P. O. 210088, University of Arizona, Tucson, Arizona 85721 USA
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46
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Kimball S, Gremer JR, Huxman TE, Lawrence Venable D, Angert AL. Phenotypic Selection Favors Missing Trait Combinations in Coexisting Annual Plants. Am Nat 2013; 182:191-207. [DOI: 10.1086/671058] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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47
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Huxman TE, Kimball S, Angert AL, Gremer JR, Barron-Gafford GA, Venable DL. Understanding past, contemporary, and future dynamics of plants, populations, and communities using Sonoran Desert winter annuals. AMERICAN JOURNAL OF BOTANY 2013; 100:1369-1380. [PMID: 23838034 DOI: 10.3732/ajb.1200463] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Global change requires plant ecologists to predict future states of biological diversity to aid the management of natural communities, thus introducing a number of significant challenges. One major challenge is considering how the many interacting features of biological systems, including ecophysiological processes, plant life histories, and species interactions, relate to performance in the face of a changing environment. We have employed a functional trait approach to understand the individual, population, and community dynamics of a model system of Sonoran Desert winter annual plants. We have used a comprehensive approach that connects physiological ecology and comparative biology to population and community dynamics, while emphasizing both ecological and evolutionary processes. This approach has led to a fairly robust understanding of past and contemporary dynamics in response to changes in climate. In this community, there is striking variation in physiological and demographic responses to both precipitation and temperature that is described by a trade-off between water-use efficiency (WUE) and relative growth rate (RGR). This community-wide trade-off predicts both the demographic and life history variation that contribute to species coexistence. Our framework has provided a mechanistic explanation to the recent warming, drying, and climate variability that has driven a surprising shift in these communities: cold-adapted species with more buffered population dynamics have increased in relative abundance. These types of comprehensive approaches that acknowledge the hierarchical nature of biology may be especially useful in aiding prediction. The emerging, novel and nonstationary climate constrains our use of simplistic statistical representations of past plant behavior in predicting the future, without understanding the mechanistic basis of change.
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Affiliation(s)
- Travis E Huxman
- Ecology and Evolutionary Biology, University of California, Irvine 92697-2525 USA.
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Leger EA. Annual plants change in size over a century of observations. GLOBAL CHANGE BIOLOGY 2013; 19:2229-2239. [PMID: 23529770 DOI: 10.1111/gcb.12208] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 03/13/2013] [Indexed: 06/02/2023]
Abstract
Studies have documented changes in animal body sizes over the last century, but very little is known about changes in plant sizes, even though reduced plant productivity is potentially responsible for declines in size of other organisms. Here, I ask whether warming trends in the Great Basin have affected plant size by measuring specimens preserved on herbarium sheets collected between 1893 and 2011. I asked how maximum and minimum temperatures, precipitation, and the Pacific Decadal Oscillation (PDO) in the year of collection affected plant height, leaf size, and flower number, and asked whether changes in climate resulted in decreasing sizes for seven annual forbs. Species had contrasting responses to climate factors, and would not necessarily be expected to respond in parallel to climatic shifts. There were generally positive relationships between plant size and increased minimum and maximum temperatures, which would have been predicted to lead to small increases in plant sizes over the observation period. While one species increased in size and flower number over the observation period, five of the seven species decreased in plant height, four of these decreased in leaf size, and one species also decreased in flower production. One species showed no change. The mechanisms behind these size changes are unknown, and the limited data available on these species (germination timing, area of occupancy, relative abundance) did not explain why some species shrank while others grew or did not change in size over time. These results show that multiple annual forbs are decreasing in size, but that even within the same functional group, species may have contrasting responses to similar environmental stimuli. Changes in plant size could have cascading effects on other members of these communities, and differential responses to directional change may change the composition of plant communities over time.
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Affiliation(s)
- Elizabeth A Leger
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, Reno, NV 89509, USA.
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Schwinning S, Kelly CK. Plant competition, temporal niches and implications for productivity and adaptability to climate change in water-limited environments. Funct Ecol 2013. [DOI: 10.1111/1365-2435.12115] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Susanne Schwinning
- Department of Biology; Texas State University; San Marcos; Texas 78666; USA
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Gremer JR, Kimball S, Angert AL, Venable DL, Huxman TE. Variation in photosynthetic response to temperature in a guild of winter annual plants. Ecology 2013; 93:2693-704. [PMID: 23431599 DOI: 10.1890/12-0006.1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
How species respond to environmental variation can have important consequences for population and community dynamics. Temperature, in particular, is one source of variation expected to strongly influence plant performance. Here, we compared photosynthetic responses to temperature across a guild of winter annual plants. Previous work in this system identified a trade-off between relative growth rate (RGR) and water-use efficiency (WUE) that predicts species differences in population dynamics over time, which then contribute to long-term species coexistence. Interestingly, species with high WUE invest in photosynthetic processes that appear to maximize carbon assimilation, while high-RGR species appear to maximize carbon gain by increasing leaf area for photosynthesis. In high-WUE species, higher rates of carbon acquisition were associated with increased investment into light-driven electron transport (J(max)). We tested whether such allocation allows these plants to have greater photosynthetic performance at lower temperatures by comparing the temperature sensitivity of photosynthesis across species in the community. Six species were grown in buried pots in the field, allowing them to experience natural changes in seasonal temperature. Plants were taken from the field and placed in growth chambers where photosynthetic performance was measured following short-term exposure to a wide range of temperatures. These measurements were repeated throughout the season. Our results suggest that high-WUE species are more efficient at processing incoming light, as measured by chlorophyll fluorescence, and exhibit higher net photosynthetic rates (A(net)) than high-RGR species, and these advantages are greatest at low temperatures. Sampling date differentially affected fluorescence across species, while species had similar seasonal changes in A(net). Our results suggest that species-specific responses to temperature contribute to the WUE-RGR trade-off that has been shown to promote coexistence in this community. These differential responses to environmental conditions can have important effects on fitness, population dynamics, and community structure.
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Affiliation(s)
- Jennifer R Gremer
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona 85721, USA.
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