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Waananen A, Richardson LK, Thoen RD, Nordstrom SW, Eichenberger EG, Kiefer G, Dykstra AB, Shaw RG, Wagenius S. High Juvenile Mortality Overwhelms Benefits of Mating Potential for Reproductive Fitness. Am Nat 2024; 203:E188-E199. [PMID: 38781531 DOI: 10.1086/730112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
AbstractAn individual's access to mates (i.e., its "mating potential") can constrain its reproduction but may also influence its fitness through effects on offspring survival. For instance, mate proximity may correspond with relatedness and lead to inbreeding depression in offspring. While offspring production and survival might respond differently to mating potential, previous studies have not considered the simultaneous effects of mating potential on these fitness components. We investigated the relationship of mating potential with both production and survival of offspring in populations of a long-lived herbaceous perennial, Echinacea angustifolia. Across 7 years and 14 sites, we quantified the mating potential of maternal plants in 1,278 mating bouts and followed the offspring from these bouts over 8 years. We used aster models to evaluate the relationship of mating potential with the number of offspring that emerged and that were alive after 8 years. Seedling emergence increased with mating potential. Despite this, the number of offspring surviving after 8 years showed no relationship to mating potential. Our results support the broader conclusion that the effect of mating potential on fitness erodes over time because of demographic stochasticity at the maternal level.
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Ramanauskas K, Igić B. kakapo: easy extraction and annotation of genes from raw RNA-seq reads. PeerJ 2023; 11:e16456. [PMID: 38034874 PMCID: PMC10688300 DOI: 10.7717/peerj.16456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 10/23/2023] [Indexed: 12/02/2023] Open
Abstract
kakapo (kākāpō) is a Python-based pipeline that allows users to extract and assemble one or more specified genes or gene families. It flexibly uses original RNA-seq read or GenBank SRA accession inputs without performing global assembly of entire transcriptomes or metatranscriptomes. The pipeline identifies open reading frames in the assembled gene transcripts and annotates them. It optionally filters raw reads for ribosomal, plastid, and mitochondrial reads, or reads belonging to non-target organisms (e.g., viral, bacterial, human). kakapo can be employed for targeted assembly, to extract arbitrary loci, such as those commonly used for phylogenetic inference in systematics or candidate genes and gene families in phylogenomic and metagenomic studies. We provide example applications and discuss how its use can offset the declining value of GenBank's single-gene databases and help assemble datasets for a variety of phylogenetic analyses.
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Affiliation(s)
- Karolis Ramanauskas
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Boris Igić
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, United States of America
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Beck J, Waananen A, Wagenius S. Habitat fragmentation decouples fire-stimulated flowering from plant reproductive fitness. Proc Natl Acad Sci U S A 2023; 120:e2306967120. [PMID: 37722060 PMCID: PMC10523459 DOI: 10.1073/pnas.2306967120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 08/03/2023] [Indexed: 09/20/2023] Open
Abstract
Many plant species in historically fire-dependent ecosystems exhibit fire-stimulated flowering. While greater reproductive effort after fire is expected to result in increased reproductive outcomes, seed production often depends on pollination, the spatial distribution of prospective mates, and the timing of their reproductive activity. Fire-stimulated flowering may thus have limited fitness benefits in small, isolated populations where mating opportunities are restricted and pollination rates are low. We conducted a 6-y study of 6,357 Echinacea angustifolia (Asteraceae) individuals across 35 remnant prairies in Minnesota (USA) to experimentally evaluate how fire effects on multiple components of reproduction vary with population size in a common species. Fire increased annual reproductive effort across populations, doubling the proportion of plants in flower and increasing the number of flower heads 65% per plant. In contrast, fire's influence on reproductive outcomes differed between large and small populations, reflecting the density-dependent effects of fire on spatiotemporal mating potential and pollination. In populations with fewer than 20 individuals, fire did not consistently increase pollination or annual seed production. Above this threshold, fire increased mating potential, leading to a 24% increase in seed set and a 71% increase in annual seed production. Our findings suggest that density-dependent effects of fire on pollination largely determine plant reproductive outcomes and could influence population dynamics across fire-dependent systems. Failure to account for the density-dependent effects of fire on seed production may lead us to overestimate the beneficial effects of fire on plant demography and the capacity of fire to maintain plant diversity, especially in fragmented habitats.
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Affiliation(s)
- Jared Beck
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, Glencoe, IL60022
| | - Amy Waananen
- Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN55108
| | - Stuart Wagenius
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, Glencoe, IL60022
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Richardson LK, Beck J, Eck DJ, Shaw R, Wagenius S. Fire effects on plant reproductive fitness vary among individuals, reflecting pollination-dependent mechanisms. AMERICAN JOURNAL OF BOTANY 2023; 110:e16160. [PMID: 36943018 DOI: 10.1002/ajb2.16160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 05/11/2023]
Abstract
PREMISE Fire induces flowering in many plant species worldwide, potentially improving reproductive fitness via greater availability of resources, as evident by flowering effort, and improved pollination outcomes, as evident by seed set. Postfire increases in flowering synchrony, and thus mating opportunities, may improve pollination. However, few studies evaluate fire effects on multiple components of fitness. Consequently, the magnitude and mechanism of fire effects on reproductive fitness remain unclear. METHODS Over multiple years and prescribed burns in a prairie preserve, we counted flowering stems, flowers, fruits, and seeds of three prairie perennials, Echinacea angustifolia, Liatris aspera, and Solidago speciosa. We used aster life-history models to assess how fire and mating opportunities influenced annual maternal fitness and its components in individual plants. RESULTS In Echinacea and Liatris, but not in Solidago, fire increased head counts, and both fire and mating opportunities increased maternal fitness. Burned Echinacea and Liatris plants with many flower heads produced many seeds despite low seed set (fertilization rates). In contrast, plants with an average number of flower heads had high seed set and produced many seeds only when mating opportunities were abundant. CONCLUSIONS Fire increased annual reproductive fitness via resource- and pollination-dependent mechanisms in Echinacea and Liatris but did not affect Solidago fitness. The consistent relationship between synchrony and seed set implies that temporal mating opportunities play an important role in pollination. While fire promotes flowering in many plant species, our results reveal that even closely related species exhibit differential responses to fire, which could impact the broader plant community.
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Affiliation(s)
- Lea K Richardson
- Program in Plant Biology and Conservation, Northwestern University, 2205 Tech Drive, Hogan 6-140B, Evanston, Illinois, 60208, USA
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, Illinois, 60022, USA
- Department of Biology, California State University Northridge, 18111 Nordhoff Street, Northridge, Califorrnia, 91330, USA
| | - Jared Beck
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, Illinois, 60022, USA
| | - Daniel J Eck
- Department of Statistics, University of Illinois, Computing Applications Building, Room 152, 605 E. Springfield Avenue, Champaign, Illinois, 61820, USA
| | - Ruth Shaw
- Department of Ecology, Evolution, and Behavior, University of Minnesota, 206 Ecology, 1987 Upper Buford Circle, St. Paul, Minnesota, 55108, USA
| | - Stuart Wagenius
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, Illinois, 60022, USA
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Reed WJ, Ison JL, Waananen A, Shaw FH, Wagenius S, Shaw RG. Genetic variation in reproductive timing in a long-lived herbaceous perennial. AMERICAN JOURNAL OF BOTANY 2022; 109:1861-1874. [PMID: 36112607 DOI: 10.1002/ajb2.16072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 09/04/2022] [Accepted: 09/06/2022] [Indexed: 06/15/2023]
Abstract
PREMISE Reproductive fitness of individual plants depends on the timing of flowering, especially in mate-limited populations, such as those in fragmented habitats. When flowering time traits are associated with differential reproductive success, the narrow-sense heritability (h2 ) of traits will determine how rapidly trait means evolve in response to selection. Heritability of flowering time is documented in many annual plants. However, estimating h2 of flowering time in perennials presents additional methodological challenges, often including paternity assignment and trait expression over multiple years. METHODS We evaluated the h2 of onset and duration of flowering using offspring-midparent regressions and restricted maximum likelihood methods in an experimental population of an iterocarpic, perennial, herbaceous plant, Echinacea angustifolia, growing in natural conditions. We assessed the flowering time of the parental cohort in 2005 and 2006; the offspring in 2014 through 2017. We also examined the effects of the paternity assignment from Cervus and MasterBayes on estimates of h2 . RESULTS We found substantial h2 for onset and duration of flowering. We also observed variation in estimates among years. The most reliable estimates for both traits fell in the range of 0.1-0.17. We found evidence of a genotype by year interaction for onset of flowering and strong evidence that genotypes are consistent in their duration of flowering across years. CONCLUSIONS Substantial heritabilities in this population imply the capacity for a response to natural selection, while also suggesting the potential for differential contributions to adaptive evolution among seasons.
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Affiliation(s)
- Will J Reed
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, 1900 Pleasant Street, Boulder, CO, 80309, USA
| | - Jennifer L Ison
- Biology Department, College of Wooster, 1189 Beall Avenue, Wooster, OH, 44691, USA
| | - Amy Waananen
- Department of Ecology, Evolution and Behavior, University of Minnesota, 1479 Gortner Avenue, St. Paul, MN, 55108, USA
| | - Frank H Shaw
- Math Department, Hamline University, 1536 Hewitt Avenue, Saint Paul, MN, 55104, USA
| | - Stuart Wagenius
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL, 60022, USA
| | - Ruth G Shaw
- Department of Ecology, Evolution and Behavior, University of Minnesota, 1479 Gortner Avenue, St. Paul, MN, 55108, USA
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Boyd JN, Anderson JT, Brzyski J, Baskauf C, Cruse-Sanders J. Eco-evolutionary causes and consequences of rarity in plants: a meta-analysis. THE NEW PHYTOLOGIST 2022; 235:1272-1286. [PMID: 35460282 DOI: 10.1111/nph.18172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 04/11/2022] [Indexed: 06/14/2023]
Abstract
Species differ dramatically in their prevalence in the natural world, with many species characterized as rare due to restricted geographic distribution, low local abundance and/or habitat specialization. We investigated the ecoevolutionary causes and consequences of rarity with phylogenetically controlled metaanalyses of population genetic diversity, fitness and functional traits in rare and common congeneric plant species. Our syntheses included 252 rare species and 267 common congeners reported in 153 peer-reviewed articles published from 1978 to 2020 and one manuscript in press. Rare species have reduced population genetic diversity, depressed fitness and smaller reproductive structures than common congeners. Rare species also could suffer from inbreeding depression and reduced fertilization efficiency. By limiting their capacity to adapt and migrate, these characteristics could influence contemporary patterns of rarity and increase the susceptibility of rare species to rapid environmental change. We recommend that future studies present more nuanced data on the extent of rarity in focal species, expose rare and common species to ecologically relevant treatments, including reciprocal transplants, and conduct quantitative genetic and population genomic analyses across a greater array of systems. This research could elucidate the processes that contribute to rarity and generate robust predictions of extinction risks under global change.
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Affiliation(s)
- Jennifer Nagel Boyd
- Department of Biology, Geology, and Environmental Science, University of Tennessee at Chattanooga, 615 McCallie Avenue, Chattanooga, TN, 37403, USA
| | - Jill T Anderson
- Department of Genetics, University of Georgia, 120 Green Street, Athens, GA, 30602, USA
| | - Jessica Brzyski
- Department of Biology, Seton Hill University, 1 Seton Hill Drive, Greensburg, PA, 15601, USA
| | - Carol Baskauf
- Department of Biology, Austin Peay State University, PO Box 4718, Clarksville, TN, 37044, USA
| | - Jennifer Cruse-Sanders
- State Botanical Garden of Georgia, University of Georgia, 2450 S. Milledge Avenue, Athens, GA, 30605, USA
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Richardson LK, Wagenius S. Fire influences reproductive outcomes by modifying flowering phenology and mate-availability. THE NEW PHYTOLOGIST 2022; 233:2083-2093. [PMID: 34921422 DOI: 10.1111/nph.17923] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 12/05/2021] [Indexed: 06/14/2023]
Abstract
A recent study posited that fire in grasslands promotes persistence of plant species by improving mating opportunities and reproductive outcomes. We devised an investigation to test these predicted mechanisms in two widespread, long-lived perennials. We expect fire to synchronize flowering, increase mating and boost seed set. We quantified individual flowering phenology and seed set of Liatris aspera and Solidago speciosa for 3 yr on a preserve in Minnesota, USA. The preserve comprises two management units burned on alternating years, allowing for comparisons between plants in burned and unburned areas within the same year, and plants in the same area across years with and without burns. Fire increased flowering synchrony and increased time between start date and peak flowering. Individuals of both species that initiated flowering later in the season had higher seed set. Fire was associated with substantially higher flowering rates and seed set in L. aspera but not S. speciosa. In L. aspera, greater synchrony was associated with increased mean seed set. Although fire affected flowering phenology in both species, reproductive success improved only in the species in which fire also synchronized among-year flowering. Our results support the hypothesis that reproduction in some grassland species benefits from fire.
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Affiliation(s)
- Lea K Richardson
- Program in Plant Biology and Conservation, Northwestern University, 2205 Tech Drive - Hogan 6-140B, Evanston, IL, 60208, USA
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL, 60022, USA
| | - Stuart Wagenius
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL, 60022, USA
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Gavin‐Smyth N, Kramer AT, Urbina‐Casanova R, Vitt P, Fant JB. Genetic rescue reduces mate limitation in a threatened, clonal, and self‐incompatible plant species. Restor Ecol 2021. [DOI: 10.1111/rec.13458] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nora Gavin‐Smyth
- Plant Biology and Conservation Northwestern University Evanston IL 60201 U.S.A
- Negaunee Institute for Plant Conservation Science and Action Chicago Botanic Garden Glencoe IL 60022 U.S.A
| | - Andrea T. Kramer
- Plant Biology and Conservation Northwestern University Evanston IL 60201 U.S.A
- Negaunee Institute for Plant Conservation Science and Action Chicago Botanic Garden Glencoe IL 60022 U.S.A
| | - Rafael Urbina‐Casanova
- Plant Biology and Conservation Northwestern University Evanston IL 60201 U.S.A
- Negaunee Institute for Plant Conservation Science and Action Chicago Botanic Garden Glencoe IL 60022 U.S.A
| | - Pati Vitt
- Plant Biology and Conservation Northwestern University Evanston IL 60201 U.S.A
- Negaunee Institute for Plant Conservation Science and Action Chicago Botanic Garden Glencoe IL 60022 U.S.A
- Lake County Forest Preserve District 1899 W. Winchester Road, Libertyville IL 60048 U.S.A
| | - Jeremie B. Fant
- Plant Biology and Conservation Northwestern University Evanston IL 60201 U.S.A
- Negaunee Institute for Plant Conservation Science and Action Chicago Botanic Garden Glencoe IL 60022 U.S.A
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Nordstrom SW, Dykstra AB, Wagenius S. Fires slow population declines of a long-lived prairie plant through multiple vital rates. Oecologia 2021; 196:679-691. [PMID: 34076744 DOI: 10.1007/s00442-021-04955-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 05/26/2021] [Indexed: 11/28/2022]
Abstract
In grasslands worldwide, modified fire cycles are accelerating herbaceous species extinctions. Fire may avert population declines by increasing survival, reproduction, or both. Survival and growth after fires may be promoted by removal of competitors or biomass and increasing resource availability. Fire-stimulated reproduction may also contribute to population growth through bolstered recruitment. We quantified these influences of fire on population dynamics in Echinacea angustifolia, a perennial forb in North American tallgrass prairie. We first used four datasets, 7-21 years long, to estimate fire's influences on survival, flowering, and recruitment. We then used matrix projection models to estimate growth rates across several burn frequencies in five populations, each with one to four burns over 15 years. Finally, we estimated the contribution of fire-induced changes in each vital rate to changes in population growth. Population growth rates generally increased with burning. The demographic process underpinning these increases depended on juvenile survival. In populations with high juvenile survival, fire-induced increases in seedling recruitment and juvenile survival enhanced population growth. However, in populations with low juvenile survival, small changes in adult survival drove growth rate changes. Regardless of burn frequencies, our models suggest populations are declining and that recruitment and juvenile survival critically influence population response to fire. However, crucially, increased seedling recruitment only increases population growth rates when enough new recruits reach reproductive maturity. The importance of recruitment and juvenile survival is especially relevant for small populations in fragmented habitats subject to mate-limiting Allee effects and inbreeding depression, which reduce recruitment and survival, respectively.
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Affiliation(s)
- Scott W Nordstrom
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, 1000 Lake Cook Rd, Glencoe, IL, 60022, USA. .,BioFrontiers Institute, University of Colorado Boulder, 3145 Colorado Avenue, Boulder, CO, 80303, USA. .,Department of Ecology and Evolutionary Biology, University of Colorado Boulder, 1900 Pleasant Street, 334 UCB, Boulder, CO, 80309, USA.
| | - Amy B Dykstra
- Department of Biological Sciences, Bethel University, 3900 Bethel Drive, St. Paul, MN, 55112, USA
| | - Stuart Wagenius
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, 1000 Lake Cook Rd, Glencoe, IL, 60022, USA
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Evolutionary history and genetic connectivity across highly fragmented populations of an endangered daisy. Heredity (Edinb) 2021; 126:846-858. [PMID: 33608651 PMCID: PMC8102499 DOI: 10.1038/s41437-021-00413-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 01/24/2021] [Accepted: 01/25/2021] [Indexed: 01/31/2023] Open
Abstract
Conservation management can be aided by knowledge of genetic diversity and evolutionary history, so that ecological and evolutionary processes can be preserved. The Button Wrinklewort daisy (Rutidosis leptorrhynchoides) was a common component of grassy ecosystems in south-eastern Australia. It is now endangered due to extensive habitat loss and the impacts of livestock grazing, and is currently restricted to a few small populations in two regions >500 km apart, one in Victoria, the other in the Australian Capital Territory and nearby New South Wales (ACT/NSW). Using a genome-wide SNP dataset, we assessed patterns of genetic structure and genetic differentiation of 12 natural diploid populations. We estimated intrapopulation genetic diversity to scope sources for genetic management. Bayesian clustering and principal coordinate analyses showed strong population genetic differentiation between the two regions, and substantial substructure within ACT/NSW. A coalescent tree-building approach implemented in SNAPP indicated evolutionary divergence between the two distant regions. Among the populations screened, the last two known remaining Victorian populations had the highest genetic diversity, despite having among the lowest recent census sizes. A maximum likelihood population tree method implemented in TreeMix suggested little or no recent gene flow except potentially between very close neighbours. Populations that were more genetically distinctive had lower genetic diversity, suggesting that drift in isolation is likely driving population differentiation though loss of diversity, hence re-establishing gene flow among them is desirable. These results provide background knowledge for evidence-based conservation and support genetic rescue within and between regions to elevate genetic diversity and alleviate inbreeding.
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Mariotti R, Pandolfi S, De Cauwer I, Saumitou‐Laprade P, Vernet P, Rossi M, Baglivo F, Baldoni L, Mousavi S. Diallelic self-incompatibility is the main determinant of fertilization patterns in olive orchards. Evol Appl 2021; 14:983-995. [PMID: 33897815 PMCID: PMC8061272 DOI: 10.1111/eva.13175] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 11/13/2020] [Accepted: 11/19/2020] [Indexed: 01/28/2023] Open
Abstract
Self-incompatibility (SI) in flowering plants potentially represents a major obstacle for sexual reproduction, especially when the number of S-alleles is low. The situation is extreme in the commercially important olive tree, where in vitro pollination assays suggested the existence of a diallelic SI (DSI) system involving only two groups (G1 and G2). Varieties belonging to the same SI group cannot fertilize each other, such that successful fruit production is predicted to require pollination between varieties of different groups. To test this prediction, we explored the extent to which the DSI system determines fertilization patterns under field conditions. One hundred and seventeen olive cultivars were first genotyped using 10 highly polymorphic dinucleotide Simple Sequence Repeat (SSR) markers to ascertain varietal identity. Cultivars were then phenotyped through controlled pollination tests to assign each of them to one of the two SI groups. We then collected and genotyped 1440 open pollinated embryos from five different orchards constituted of seven local cultivars with known group of incompatibility groups. Embryos genotype information were used: (i) to assign embryos to the most likely pollen donor genotype in the neighbourhood using paternity analysis, and (ii) to compare the composition of the pollen cloud genetic among recipient trees in the five sites. The paternity analysis showed that the DSI system is the main determinant of fertilization success under field open pollination conditions: G1 cultivars sired seeds exclusively on G2 cultivars, and reciprocally. No self-fertilization events were observed. Our results demonstrate that DSI is a potent force determining pollination success among varieties within olive orchards used for production. They have the potential to improve management practices by guiding the selection of compatible varieties to avoid planting orchards containing sets of varieties with strongly unbalanced SI groups, as these would lead to suboptimal olive production.
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Affiliation(s)
| | | | | | | | | | - Martina Rossi
- Institute of Biosciences and BioresourcesCNRPerugiaItaly
| | | | | | - Soraya Mousavi
- Institute of Biosciences and BioresourcesCNRPerugiaItaly
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12
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Zaya DN, Leicht-Young SA, Pavlovic NB, Ashley MV. Heterospecific pollination by an invasive congener threatens the native American bittersweet, Celastrus scandens. PLoS One 2021; 16:e0248635. [PMID: 33755682 PMCID: PMC7987179 DOI: 10.1371/journal.pone.0248635] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 03/02/2021] [Indexed: 11/19/2022] Open
Abstract
Invasive plants have the potential to interfere with native species’ reproductive success through a number of mechanisms, including heterospecific pollination and hybridization. This study investigated reproductive interactions between a native North American woody vine (American bittersweet, Celastrus scandens) and an introduced congener (oriental bittersweet, C. orbiculatus). The decline of C. scandens in the eastern portion of its range is coincident with the introduction and spread of C. orbiculatus, and the two species are known to hybridize. The relationship between proximity and floral production of conspecific and heterospecific males on fertilization and hybridization rates was measured at a field site in northwestern Indiana, USA where both species occur and reproduce. We found that the invasive vine had an extreme advantage in both male and female floral production, producing nearly 200 times more flowers per staminate plant and 65 times more flowers per pistillate plant than the native. Using nuclear microsatellite DNA markers we found that hybridization rates were asymmetric; 39% of the C. scandens seeds tested were hybrids, compared to only 1.6% of C. orbiculatus seeds. The asymmetric hybridization rates were likely not solely due to greater abundance of C. orbiculatus pollen because experimental hand crosses revealed that C. scandens had a higher rate (41%) of heterospecific fertilization than C. orbiculatus (2.4%). We previously reported that few hybrids were observed in the wild, and hybrids had greatly reduced fecundity. Thus, in our system, the threat posed by heterospecific pollen is not replacement by hybrids or introgression, but rather asymmetric reproductive interference. Reproductive interference extended to distances as great as 100 meters, thus, efforts to conserve the native species must reduce its exposure to C. orbiculatus over a relatively large spatial scale.
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Affiliation(s)
- David N. Zaya
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
- * E-mail:
| | - Stacey A. Leicht-Young
- U.S. Geological Survey, Great Lakes Science Center, Chesterton, Indiana, United States of America
| | - Noel B. Pavlovic
- U.S. Geological Survey, Great Lakes Science Center, Chesterton, Indiana, United States of America
| | - Mary V. Ashley
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
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Kulbaba MW, Shaw RG. Lifetime Fitness through Female and Male Function: Influences of Genetically Effective Population Size and Density. Am Nat 2021; 197:434-447. [PMID: 33755534 DOI: 10.1086/713067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractAn individual's lifetime fitness and patterns of mating between individuals are interdependent features of sexual organisms. Mating systems (outcrossing vs. selfing or mating between close relatives) can affect the distribution of offspring fitness, which generally declines with inbreeding, which in turn is related to a population's genetically effective size (Ne). Fitness and mating patterns are also expected to vary with proximity of mates (i.e., population density). Consequently, density and Ne may influence demographic and genetic changes over generations and interact in their effects. Here, we report an experiment designed to assess the influence of these two population-level properties on mating system and lifetime fitness. In experimental arrays under quasi-natural conditions, we varied the density and Ne of the hermaphroditic annual legume Chamaecrista fasciculata. We recorded components of fitness for each individual and employed microsatellite markers to estimate outcrossing and assign paternity. We used aster analyses to estimate lifetime fitness for genetic families using female (seeds set) and male (seeds sired) reproduction as fitness measures. With estimates from these analyses, we assessed the evidence for a trade-off between fitness attained through female versus male function, but we found none. Lifetime fitness increased with density, especially under high Ne. Outcrossing rates increased with density under high Ne but declined modestly with density under low Ne. Our results show that density and Ne have strong direct effects on fitness and mating systems, with negative fitness effects of low Ne limiting the positive effects of increasing density. These findings highlight the importance of the interactive effects of density and Ne on lifetime fitness.
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Durand E, Chantreau M, Le Veve A, Stetsenko R, Dubin M, Genete M, Llaurens V, Poux C, Roux C, Billiard S, Vekemans X, Castric V. Evolution of self-incompatibility in the Brassicaceae: Lessons from a textbook example of natural selection. Evol Appl 2020; 13:1279-1297. [PMID: 32684959 PMCID: PMC7359833 DOI: 10.1111/eva.12933] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/25/2020] [Accepted: 01/29/2020] [Indexed: 12/14/2022] Open
Abstract
Self-incompatibility (SI) is a self-recognition genetic system enforcing outcrossing in hermaphroditic flowering plants and results in one of the arguably best understood forms of natural (balancing) selection maintaining genetic variation over long evolutionary times. A rich theoretical and empirical population genetics literature has considerably clarified how the distribution of SI phenotypes translates into fitness differences among individuals by a combination of inbreeding avoidance and rare-allele advantage. At the same time, the molecular mechanisms by which self-pollen is specifically recognized and rejected have been described in exquisite details in several model organisms, such that the genotype-to-phenotype map is also pretty well understood, notably in the Brassicaceae. Here, we review recent advances in these two fronts and illustrate how the joint availability of detailed characterization of genotype-to-phenotype and phenotype-to-fitness maps on a single genetic system (plant self-incompatibility) provides the opportunity to understand the evolutionary process in a unique perspective, bringing novel insight on general questions about the emergence, maintenance, and diversification of a complex genetic system.
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Affiliation(s)
| | | | - Audrey Le Veve
- CNRSUniv. LilleUMR 8198 ‐ Evo‐Eco‐PaleoF-59000 LilleFrance
| | | | - Manu Dubin
- CNRSUniv. LilleUMR 8198 ‐ Evo‐Eco‐PaleoF-59000 LilleFrance
| | - Mathieu Genete
- CNRSUniv. LilleUMR 8198 ‐ Evo‐Eco‐PaleoF-59000 LilleFrance
| | - Violaine Llaurens
- Institut de Systématique, Evolution et Biodiversité (ISYEB)Muséum national d'Histoire naturelleCNRS, Sorbonne Université, EPHE, Université des Antilles CP 5057 rue Cuvier, 75005 ParisFrance
| | - Céline Poux
- CNRSUniv. LilleUMR 8198 ‐ Evo‐Eco‐PaleoF-59000 LilleFrance
| | - Camille Roux
- CNRSUniv. LilleUMR 8198 ‐ Evo‐Eco‐PaleoF-59000 LilleFrance
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Byers DL. Impact of prairie fragment size on proportion of females and reproductive success of Lobelia spicata Lam., a gynodioecious species. PLANT BIOLOGY (STUTTGART, GERMANY) 2020; 22:137-145. [PMID: 31618510 DOI: 10.1111/plb.13055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 10/07/2019] [Indexed: 06/10/2023]
Abstract
Due to ongoing human impacts, plant species increasingly occur in landscapes that are highly fragmented, with remaining natural habitats occupying small areas, resulting in populations that are smaller and more isolated than in previous time periods. This changed metapopulation structure is expected to have negative impacts on seed production. For example, the proportion of female plants within gynodioecious populations may be more volatile due to genetic drift in small populations associated with small habitat fragments, with concomitant impacts on seed production. My aims were to determine: (i) if variation in proportion of females is larger in smaller fragments; and (ii) if such changes in female frequency in small fragments result in reduced seed production. Thirty-two populations of Lobelia spicata Lam., a gynodioecious species, were surveyed in 2000, 2001 and 2009 in the tallgrass prairie region of Midwestern North America (Illinois and Indiana, USA). Data were collected for: proportion of female plants, total number of flowering plants (measure of population size), seed set per plant and prairie fragment size (another measure of population size). The proportion of females is more variable in smaller prairie fragments. Seed number per fruit decreases as the proportion of females increases in a population, but only significantly for female plants. The number of flowering plants is positively associated with fruit production for both genders. Populations within larger prairie fragments have higher seed production. The reproductive consequences of habitat fragmentation depend on the plant breeding system. While both sexes were negatively impacted, females were more adversely affected.
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Affiliation(s)
- D L Byers
- School of Biological Sciences, Illinois State University, Normal, IL, USA
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16
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Fire synchronizes flowering and boosts reproduction in a widespread but declining prairie species. Proc Natl Acad Sci U S A 2020; 117:3000-3005. [PMID: 31988124 DOI: 10.1073/pnas.1907320117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fire is an important determinant of habitat structure and biodiversity across ecosystems worldwide. In fire-dependent communities, similar to the North American prairie, fire suppression contributes to local plant extinctions. Yet the demographic mechanisms responsible for species loss have not been directly investigated. We conducted a 21-y longitudinal study of 778 individual plants of Echinacea angustifolia, a widespread perennial species with chronically limited mating opportunities, to explore how fire affects reproduction. In a large preserve, with management units on different burn schedules, we investigated Echinacea mating scenes, which quantify isolation from potential mates and overlap in the timing of flowering, to determine the extent to which fire influences the potential for sexual reproduction. We demonstrate that fire consistently increased mating opportunities by synchronizing reproductive effort. Each fire occurred during fall or spring and stimulated flowering in the subsequent summer, thus synchronizing reproduction among years and increasing the proximity of potential mates after a fire. Greater within-season flowering synchrony in postfire mating scenes further increased mating potential. The improved postfire mating scene enhanced reproduction by increasing pollination efficiency. Seed set in scenes postfire exceeded other scenes by 55%, and annual fecundity nearly doubled (88% increase). We predict the reproductive benefits of synchronized flowering after fire can alleviate mate-finding Allee effects, promote population growth, and forestall local extirpation in small populations of Echinacea and many other prairie species. Furthermore, the synchronization of flowering by burning may improve mating opportunities, reproduction, and the likelihood of persistence for many other plant species in fire-dependent habitats.
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17
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Page ML, Ison JL, Bewley AL, Holsinger KM, Kaul AD, Koch KE, Kolis KM, Wagenius S. Pollinator effectiveness in a composite: a specialist bee pollinates more florets but does not move pollen farther than other visitors. AMERICAN JOURNAL OF BOTANY 2019; 106:1487-1498. [PMID: 31713237 DOI: 10.1002/ajb2.1383] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 09/23/2019] [Indexed: 06/10/2023]
Abstract
PREMISE Variation in pollinator effectiveness may contribute to pollen limitation in fragmented plant populations. In plants with multiovulate ovaries, the number of conspecific pollen grains per stigma often predicts seed set and is used to quantify pollinator effectiveness. In the Asteraceae, however, florets are uniovulate, which suggests that the total amount of pollen deposited per floret may not measure pollinator effectiveness. We examined two aspects of pollinator effectiveness-effective pollen deposition and effective pollen movement-for insects visiting Echinacea angustifolia, a composite that is pollen limited in small, isolated populations. METHODS We filmed insect visits to Echinacea in two prairie restorations and used these videos to quantify behavior that might predict effectiveness. To quantify effective pollen deposition, we used the number of styles shriveled per visit. To quantify effective pollen movement, we conducted paternity analysis on a subset of offspring and measured the pollen movement distance between mates. RESULTS Effective pollen deposition varied among taxa. Andrena helianthiformis, a Heliantheae oligolege, was the most effective taxon, shriveling more than twice the proportion of styles as all other visitors. Differences in visitor behavior on a flowering head did not explain variation in effective pollen deposition, nor did flowering phenology. On average, visitors moved pollen 16 m between plants, and this distance did not vary among taxa. CONCLUSIONS Andrena helianthiformis is an important pollinator of Echinacea. Variation in reproductive fitness of Echinacea in fragmented habitat may result, in part, from the abundance of this species.
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Affiliation(s)
- Maureen L Page
- Department of Entomology and Nematology, University of California-Davis, One Shields Avenue, Davis, California, 95616, USA
- Biology Department, Scripps College, 1030 Columbia Avenue, Claremont, California, 91711, USA
| | - Jennifer L Ison
- Biology Department, College of Wooster, 1189 Beall Avenue, Wooster, Ohio, 44691, USA
| | - Alison L Bewley
- Biology Department, Wittenberg University, 200 W. Ward Street, Springfield, Ohio, 45504, USA
| | - Keaton M Holsinger
- Biology Department, Wabash College, 301 West Wabash Avenue, Crawfordsville, Indiana, 47933, USA
| | - Andrew D Kaul
- Biology Department, St. Olaf College, 1520 St. Olaf Avenue, Northfield, Minnesota, 55057, USA
| | - Katie E Koch
- Biology Department, Lakeland University, W3718 South Drive, Plymouth, Wisconsin, 53073, USA
| | - Kory M Kolis
- Biology Department, Gustavus Adolphus College, 800 West College Avenue, Saint Peter, Minnesota, 56082, USA
| | - Stuart Wagenius
- Division of Plant Biology and Conservation, Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, Illinois, 60022, USA
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18
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Mandel JR, Major CK, Bayer RJ, Moore JE. Clonal diversity and spatial genetic structure in the long-lived herb, Prairie trillium. PLoS One 2019; 14:e0224123. [PMID: 31634380 PMCID: PMC6802849 DOI: 10.1371/journal.pone.0224123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 10/07/2019] [Indexed: 02/03/2023] Open
Abstract
Combining population genetic studies with demographic surveys in long-lived clonal herbs can yield insight into the population dynamics of clonal plant populations. In this study, we assayed clonal diversity and spatial genetic structure in a population of a long-lived understory herb, Trillium recurvatum, that has been the focus of a demographic study spanning 26 years at the Meeman Biological Station in Memphis, Tennessee, USA. Using a set of five newly developed simple sequence repeat markers first reported here, we assessed 1) the extent of clonal diversity within the Meeman site, 2) the degree to which genetic diversity varies with stage class (juvenile, non-flowering, and flowering adults) at this site, 3) whether there is spatial genetic structure at the Meeman site, and 4) how measures of genetic diversity and inbreeding at the Meeman site compare to two additional nearby populations. Along with these analyses, we calculated and compared traditional population genetic metrics with information theory-based diversity indices. Although clonal propagation was present, the focal population displayed moderate levels of clonal diversity comprising 81 genets from the 174 individuals sampled. In the focal site, we also found that genetic diversity was highest in the flowering stage class when compared to the non-flowering and juvenile classes. We report that genets exhibited spatial genetic structure in the focal site exhibiting values for the Sp statistic of 0.00199 for linear distance and 0.0271 for log distance. Measures of unbiased gene diversity and the inbreeding coefficient were comparable across the sampled populations. Our results provide complementary genetic data to previous demographic studies in T. recurvatum, and these findings provide data for future studies aimed at integrating the degree of clonality, genetic variation, and population dynamics in this species. Our findings suggest that T. recurvatum at the focal Meeman site displays higher levels of sexual reproduction than were previously suggested, and spatial genetic structure estimates were comparable to other plant species with mixed and outcrossing mating strategies.
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Affiliation(s)
- Jennifer R. Mandel
- Department of Biological Sciences, The University of Memphis, Memphis, TN, United States of America
- Center for Biodiversity, The University of Memphis, Memphis, TN, United States of America
- Edward J. Meeman Biological Station, Millington, TN, United States of America
- * E-mail:
| | - C. Kendall Major
- Department of Biological Sciences, The University of Memphis, Memphis, TN, United States of America
| | - Randall J. Bayer
- Department of Biological Sciences, The University of Memphis, Memphis, TN, United States of America
- Edward J. Meeman Biological Station, Millington, TN, United States of America
| | - James E. Moore
- Edward J. Meeman Biological Station, Millington, TN, United States of America
- Department of Biology, Christian Brothers University, Memphis, TN, United States of America
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19
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Chen G, Sun W. The role of botanical gardens in scientific research, conservation, and citizen science. PLANT DIVERSITY 2018; 40:181-188. [PMID: 30740563 PMCID: PMC6137266 DOI: 10.1016/j.pld.2018.07.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 07/18/2018] [Accepted: 07/19/2018] [Indexed: 05/23/2023]
Abstract
Plant diversity is currently being lost at an unprecedented rate, resulting in an associated decrease in ecosystem services. About a third of the world's vascular plant species face the threat of extinction due to a variety of devastating activities, including, over-harvesting and over exploitation, destructive agricultural and forestry practices, urbanization, environmental pollution, land-use changes, exotic invasive species, global climate change, and more. We therefore need to increase our efforts to develop integrative conservation approaches for plant species conservation. Botanical gardens devote their resources to the study and conservation of plants, as well as making the world's plant species diversity known to the public. These gardens also play a central role in meeting human needs and providing well-being. In this minireview, a framework for the integrated missions of botanical gardens, including scientific research, in/ex situ conservation, plant resource utilization, and citizen science are cataloged. By reviewing the history of the development of Kunming Botanical Garden, we illustrate successful species conservation approaches (among others, projects involving Camellia, Rhododendron, Magnolia, Begonia, Allium, Nepenthes, medicinal plants, ornamental plants, and Plant Species with Extreme Small Populations), as well as citizen science, and scientific research at Kunming Botanical Garden over the past 80 years. We emphasize that Kunming Botanical Garden focuses largely on the ex situ conservation of plants from Southwest China, especially those endangered, endemic, and economically important plant species native to the Yunnan Plateau and the southern Hengduan Mountains. We also discuss the future challenges and responsibilities of botanical gardens in a changing world, including: the negative effects of outbreeding and/or inbreeding depression; promoting awareness, study, and conservation of plant species diversity; accelerating global access to information about plant diversity; increasing capacity building and training activities. We hope this minireview can promote understanding of the role of botanical gardens.
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Affiliation(s)
- Gao Chen
- Kunming Botanical Garden, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, Yunnan, China
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming, 650204, China
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650204, Yunnan, China
| | - Weibang Sun
- Kunming Botanical Garden, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, Yunnan, China
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming, 650204, China
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650204, Yunnan, China
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20
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Ison JL, Prescott LJ, Nordstrom SW, Waananen A, Wagenius S. Pollinator-mediated mechanisms for increased reproductive success in early flowering plants. OIKOS 2018. [DOI: 10.1111/oik.04882] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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21
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Knight TM, Ashman T, Bennett J, Burns JH, Passonneau S, Steets JA. Reflections on, and visions for, the changing field of pollination ecology. Ecol Lett 2018; 21:1282-1295. [DOI: 10.1111/ele.13094] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/10/2018] [Accepted: 04/17/2018] [Indexed: 01/03/2023]
Affiliation(s)
- T. M. Knight
- Institute of Biology Martin Luther University Halle‐Wittenberg Am Kirchtor 1 06108 Halle Germany
- Department Community Ecology Helmholtz Centre for Environmental Research – UFZ Theodor‐Lieser‐Straße 4 06120 Halle Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐Leipzig Deutscher Platz 5e 04103 Leipzig Germany
| | - T.‐L. Ashman
- Department of Biological Sciences University of Pittsburgh Pittsburgh PA15260 USA
| | - J. M. Bennett
- Institute of Biology Martin Luther University Halle‐Wittenberg Am Kirchtor 1 06108 Halle Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐Leipzig Deutscher Platz 5e 04103 Leipzig Germany
| | - J. H. Burns
- Department of Biology Case Western Reserve University Cleveland OH44106‐7080 USA
| | - S. Passonneau
- Institute of Biology Martin Luther University Halle‐Wittenberg Am Kirchtor 1 06108 Halle Germany
- Department Community Ecology Helmholtz Centre for Environmental Research – UFZ Theodor‐Lieser‐Straße 4 06120 Halle Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐Leipzig Deutscher Platz 5e 04103 Leipzig Germany
| | - J. A. Steets
- Department of Plant Biology, Ecology, and Evolution Oklahoma State University Stillwater OK74078 USA
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22
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Evans TM, Cavers S, Ennos R, Vanbergen AJ, Heard MS. Florally rich habitats reduce insect pollination and the reproductive success of isolated plants. Ecol Evol 2017; 7:6507-6518. [PMID: 28861252 PMCID: PMC5574791 DOI: 10.1002/ece3.3186] [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: 05/09/2017] [Revised: 06/26/2017] [Accepted: 05/17/2017] [Indexed: 01/25/2023] Open
Abstract
Landscape heterogeneity in floral communities has the potential to modify pollinator behavior. Pollinator foraging varies with the diversity, abundance, and spatial configuration of floral resources. However, the implications of this variation for pollen transfer and ultimately the reproductive success of insect pollinated plants remains unclear, especially for species which are rare or isolated in the landscape. We used a landscape-scale experiment, coupled with microsatellite genotyping, to explore how the floral richness of habitats affected pollinator behavior and pollination effectiveness. Small arrays of the partially self-compatible plant Californian poppy (Eschscholzia californica) were introduced across a landscape gradient to simulate rare, spatially isolated populations. The effects on pollinator activity, outcrossing, and plant reproduction were measured. In florally rich habitats, we found reduced pollen movement between plants, leading to fewer long-distance pollination events, lower plant outcrossing, and a higher incidence of pollen limitation. This pattern indicates a potential reduction in per capita pollinator visitation, as suggested by the lower activity densities and richness of pollinators observed within florally rich habitats. In addition, seed production reduced by a factor of 1.8 in plants within florally rich habitats and progeny germination reduced by a factor of 1.2. We show this to be a consequence of self-fertilization within the partially self-compatible plant, E. californica. These findings indicate that locally rare plants are at a competitive disadvantage within florally rich habitats because neighboring plant species disrupt conspecific mating by co-opting pollinators. Ultimately, this Allee effect may play an important role in determining the long-term persistence of rarer plants in the landscape, both in terms of seed production and viability. Community context therefore requires consideration when designing and implementing conservation management for plants which are comparatively rare in the landscape.
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Affiliation(s)
- Tracie M Evans
- NERC Centre for Ecology and Hydrology Wallingford UK.,Institute of Evolutionary Biology University of Edinburgh Edinburgh UK
| | - Stephen Cavers
- NERC Centre for Ecology and Hydrology Penicuik Edinburgh UK
| | - Richard Ennos
- Institute of Evolutionary Biology University of Edinburgh Edinburgh UK
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23
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Saumitou-Laprade P, Vernet P, Vekemans X, Billiard S, Gallina S, Essalouh L, Mhaïs A, Moukhli A, El Bakkali A, Barcaccia G, Alagna F, Mariotti R, Cultrera NGM, Pandolfi S, Rossi M, Khadari B, Baldoni L. Elucidation of the genetic architecture of self-incompatibility in olive: Evolutionary consequences and perspectives for orchard management. Evol Appl 2017; 10:867-880. [PMID: 29151878 PMCID: PMC5680433 DOI: 10.1111/eva.12457] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 01/05/2017] [Indexed: 12/15/2022] Open
Abstract
The olive (Olea europaea L.) is a typical important perennial crop species for which the genetic determination and even functionality of self‐incompatibility (SI) are still largely unresolved. It is still not known whether SI is under gametophytic or sporophytic genetic control, yet fruit production in orchards depends critically on successful ovule fertilization. We studied the genetic determination of SI in olive in light of recent discoveries in other genera of the Oleaceae family. Using intra‐ and interspecific stigma tests on 89 genotypes representative of species‐wide olive diversity and the compatibility/incompatibility reactions of progeny plants from controlled crosses, we confirmed that O. europaea shares the same homomorphic diallelic self‐incompatibility (DSI) system as the one recently identified in Phillyrea angustifolia and Fraxinus ornus. SI is sporophytic in olive. The incompatibility response differs between the two SI groups in terms of how far pollen tubes grow before growth is arrested within stigma tissues. As a consequence of this DSI system, the chance of cross‐incompatibility between pairs of varieties in an orchard is high (50%) and fruit production may be limited by the availability of compatible pollen. The discovery of the DSI system in O. europaea will undoubtedly offer opportunities to optimize fruit production.
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Affiliation(s)
- Pierre Saumitou-Laprade
- CNRSUMR 8198 Evo-Eco-Paleo Université de Lille - Sciences et Technologies Villeneuve d'Ascq France
| | - Philippe Vernet
- CNRSUMR 8198 Evo-Eco-Paleo Université de Lille - Sciences et Technologies Villeneuve d'Ascq France
| | - Xavier Vekemans
- CNRSUMR 8198 Evo-Eco-Paleo Université de Lille - Sciences et Technologies Villeneuve d'Ascq France
| | - Sylvain Billiard
- CNRSUMR 8198 Evo-Eco-Paleo Université de Lille - Sciences et Technologies Villeneuve d'Ascq France
| | - Sophie Gallina
- CNRSUMR 8198 Evo-Eco-Paleo Université de Lille - Sciences et Technologies Villeneuve d'Ascq France
| | | | - Ali Mhaïs
- Montpellier SupAgro UMR 1334 AGAP Montpellier France.,INRAUR Amélioration des Plantes Marrakech Morocco.,Laboratoire AgroBiotech L02B005 Faculté des Sciences et Techniques Guéliz University Cadi Ayyad Marrakech Morocco
| | | | - Ahmed El Bakkali
- INRAUR Amélioration des Plantes et Conservation des Ressources Phytogénétiques Meknès Morocco
| | - Gianni Barcaccia
- Laboratory of Genomics and Plant Breeding DAFNAE - University of Padova Legnaro PD Italy
| | - Fiammetta Alagna
- Research Unit for Table Grapes and Wine Growing in Mediterranean Environment CREATuriBA Italy.,CNRInstitute of Biosciences and BioresourcesPerugiaItaly
| | | | | | | | - Martina Rossi
- CNRInstitute of Biosciences and BioresourcesPerugiaItaly
| | - Bouchaïb Khadari
- Montpellier SupAgro UMR 1334 AGAP Montpellier France.,INRA/CBNMed UMR 1334 Amélioration Génétique et Adaptation des Plantes (AGAP) Montpellier France
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25
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Persistence of the gypsophile Lepidospartum burgessii (Asteraceae) through clonal growth and limited gene flow. CONSERV GENET 2016. [DOI: 10.1007/s10592-016-0855-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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26
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Sampson JF, Byrne M, Gibson N, Yates C. Limiting inbreeding in disjunct and isolated populations of a woody shrub. Ecol Evol 2016; 6:5867-80. [PMID: 27547361 PMCID: PMC4983598 DOI: 10.1002/ece3.2322] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 06/27/2016] [Indexed: 02/02/2023] Open
Abstract
Pollen movements and mating patterns are key features that influence population genetic structure. When gene flow is low, small populations are prone to increased genetic drift and inbreeding, but naturally disjunct species may have features that reduce inbreeding and contribute to their persistence despite genetic isolation. Using microsatellite loci, we investigated outcrossing levels, family mating parameters, pollen dispersal, and spatial genetic structure in three populations of Hakea oldfieldii, a fire-sensitive shrub with naturally disjunct, isolated populations prone to reduction in size and extinction following fires. We mapped and genotyped a sample of 102 plants from a large population, and all plants from two smaller populations (28 and 20 individuals), and genotyped 158-210 progeny from each population. We found high outcrossing despite the possibility of geitonogamous pollination, small amounts of biparental inbreeding, a limited number of successful pollen parents within populations, and significant correlated paternity. The number of pollen parents for each seed parent was moderate. There was low but significant spatial genetic structure up to 10 m around plants, but the majority of successful pollen came from outside this area including substantial proportions from distant plants within populations. Seed production varied among seven populations investigated but was not correlated with census population size. We suggest there may be a mechanism to prevent self-pollination in H. oldfieldii and that high outcrossing and pollen dispersal within populations would promote genetic diversity among the relatively small amount of seed stored in the canopy. These features of the mating system would contribute to the persistence of genetically isolated populations prone to fluctuations in size.
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Affiliation(s)
- Jane F Sampson
- Science and Conservation Division Department of Parks and Wildlife Locked Bag 104 Bentley Delivery Centre Perth Western Australia 6983 Australia
| | - Margaret Byrne
- Science and Conservation Division Department of Parks and Wildlife Locked Bag 104 Bentley Delivery Centre Perth Western Australia 6983 Australia
| | - Neil Gibson
- Science and Conservation Division Department of Parks and Wildlife Locked Bag 104 Bentley Delivery Centre Perth Western Australia 6983 Australia
| | - Colin Yates
- Science and Conservation Division Department of Parks and Wildlife Locked Bag 104 Bentley Delivery Centre Perth Western Australia 6983 Australia
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Luque GM, Vayssade C, Facon B, Guillemaud T, Courchamp F, Fauvergue X. The genetic Allee effect: a unified framework for the genetics and demography of small populations. Ecosphere 2016. [DOI: 10.1002/ecs2.1413] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Gloria M. Luque
- Ecologie Systématique EvolutionUniv. Paris‐Sud CNRS AgroParisTech, Université Paris‐Saclay 91400 Orsay France
| | - Chloé Vayssade
- ISA UMR INRA CNRS Universite Nicé Côte d'Azur 06903 Sophia‐Antipolis France
| | - Benoît Facon
- CBGP UMR INRA CIRAD IRD SupAgro 34988 Montferrier sur Lez France
| | - Thomas Guillemaud
- ISA UMR INRA CNRS Universite Nicé Côte d'Azur 06903 Sophia‐Antipolis France
| | - Franck Courchamp
- Ecologie Systématique EvolutionUniv. Paris‐Sud CNRS AgroParisTech, Université Paris‐Saclay 91400 Orsay France
- Department of Ecology and Evolutionary BiologyCenter for Tropical ResearchInstitute of the Environment and SustainabilityUniversity of California Los Angeles Los Angeles California 90095 USA
| | - Xavier Fauvergue
- ISA UMR INRA CNRS Universite Nicé Côte d'Azur 06903 Sophia‐Antipolis France
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28
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Silva JL, Brennan AC, Mejías JA. Population genetics of self-incompatibility in a clade of relict cliff-dwelling plant species. AOB PLANTS 2016; 8:plw029. [PMID: 27154621 PMCID: PMC4940477 DOI: 10.1093/aobpla/plw029] [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: 11/02/2015] [Accepted: 04/18/2016] [Indexed: 06/05/2023]
Abstract
The mating systems of species in small or fragmented populations impact upon their persistence. Small self-incompatible (SI) populations risk losing S allele diversity, responsible for the SI response, by drift thereby limiting mate availability and leading to population decline or SI system breakdown. But populations of relict and/or endemic species have resisted these demographic conditions over long periods suggesting their mating systems have adapted. To address a lack of empirical data on this topic, we studied the SI systems of three relict cliff-dwelling species of Sonchus section Pustulati (Asteraceae): S. masguindalii, S. fragilis and S. pustulatus in the western Mediterranean region. We performed controlled pollinations within and between individuals to measure index of SI (ISI) expression and identify S alleles in multiple population samples. Sonchus masguindalii and S. pustulatus showed strong SI (ISI = 0.6-1.0) compared to S. fragilis (ISI = 0.1-0.7). Just five S alleles were estimated for Spanish S. pustulatus and a moderate 11-15 S alleles for Moroccan S. pustulatus and S. fragilis, respectively. The fact that autonomous fruit set was generally improved by active self-pollination in self-compatible S. fragilis suggests that individuals with weak SI can show a wide range of outcrossing levels dependent on the degree of self or outcross pollen that pollinators bear. We conclude that frequent S allele dominance interactions that mask the incompatibility interactions of recessive S alleles leading to higher mate availability and partial breakdown of SI leading to mixed mating, both contribute to reproductive resilience in this group.
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Affiliation(s)
- Jose L Silva
- Departamento De Biología Vegetal Y Ecología, Universidad De Sevilla, Sevilla, CP 41012, España
| | - Adrian C Brennan
- School of Biological and Biomedical Sciences, University of Durham, Durham, UK
| | - José A Mejías
- Departamento De Biología Vegetal Y Ecología, Universidad De Sevilla, Sevilla, CP 41012, España
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Nantongo JS, Eilu G, Geburek T, Schueler S, Konrad H. Detection of Self Incompatibility Genotypes in Prunus africana: Characterization, Evolution and Spatial Analysis. PLoS One 2016; 11:e0155638. [PMID: 27348423 PMCID: PMC4922633 DOI: 10.1371/journal.pone.0155638] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 05/02/2016] [Indexed: 11/29/2022] Open
Abstract
In flowering plants, self-incompatibility is an effective genetic mechanism that prevents self-fertilization. Most Prunus tree species exhibit a homomorphic gametophytic self-incompatibility (GSI) system, in which the pollen phenotype is encoded by its own haploid genome. To date, no identification of S-alleles had been done in Prunus africana, the only member of the genus in Africa. To identify S-RNase alleles and hence determine S-genotypes in African cherry (Prunus africana) from Mabira Forest Reserve, Uganda, primers flanking the first and second intron were designed and these amplified two bands in most individuals. PCR bands on agarose indicated 26 and 8 different S-alleles for second and first intron respectively. Partial or full sequences were obtained for all these fragments. Comparison with published S-RNase data indicated that the amplified products were S-RNase alleles with very high interspecies homology despite the high intraspecific variation. Against expectations for a locus under balancing selection, frequency and spatial distribution of the alleles in a study plot was not random. Implications of the results to breeding efforts in the species are discussed, and mating experiments are strongly suggested to finally prove the functionality of SI in P. africana.
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Affiliation(s)
| | | | - Thomas Geburek
- Austrian Federal Office and Research Centre for Forests (BFW), Vienna, Austria
| | - Silvio Schueler
- Austrian Federal Office and Research Centre for Forests (BFW), Vienna, Austria
| | - Heino Konrad
- Austrian Federal Office and Research Centre for Forests (BFW), Vienna, Austria
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Lin C, Miriti MN, Goodell K. Demographic consequences of greater clonal than sexual reproduction in Dicentra canadensis. Ecol Evol 2016; 6:3871-83. [PMID: 27247759 PMCID: PMC4867665 DOI: 10.1002/ece3.2163] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 03/02/2016] [Accepted: 04/13/2016] [Indexed: 11/24/2022] Open
Abstract
Clonality is a widespread life history trait in flowering plants that may be essential for population persistence, especially in environments where sexual reproduction is unpredictable. Frequent clonal reproduction, however, could hinder sexual reproduction by spatially aggregating ramets that compete with seedlings and reduce inter-genet pollination. Nevertheless, the role of clonality in relation to variable sexual reproduction in population dynamics is often overlooked. We combined population matrix models and pollination experiments to compare the demographic contributions of clonal and sexual reproduction in three Dicentra canadensis populations, one in a well-forested landscape and two in isolated forest remnants. We constructed stage-based transition matrices from 3 years of census data to evaluate annual population growth rates, λ. We used loop analysis to evaluate the relative contribution of different reproductive pathways to λ. Despite strong temporal and spatial variation in seed set, populations generally showed stable growth rates. Although we detected some pollen limitation of seed set, manipulative pollination treatments did not affect population growth rates. Clonal reproduction contributed significantly more than sexual reproduction to population growth in the forest remnants. Only at the well-forested site did sexual reproduction contribute as much as clonal reproduction to population growth. Flowering plants were more likely to transition to a smaller size class with reduced reproductive potential in the following year than similarly sized nonflowering plants, suggesting energy trade-offs between sexual and clonal reproduction at the individual level. Seed production had negligible effects on growth and tuber production of individual plants. Our results demonstrate that clonal reproduction is vital for population persistence in a system where sexual reproduction is unpredictable. The bias toward clonality may be driven by low fitness returns for resource investment in sexual reproduction at the individual level. However, chronic failure in sexual reproduction may exacerbate the imbalance between sexual and clonal reproduction and eventually lead to irreversible loss of sex in the population.
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Affiliation(s)
- Chia‐Hua Lin
- Department of Evolution, Ecology and Organismal BiologyThe Ohio State University318 West 12th AvenueColumbusOhio43210
- Present address: Department of EntomologyThe Ohio State University– Ohio Agricultural Research and Development Center1680 Madison AvenueWoosterOhio44691
| | - Maria N. Miriti
- Department of Evolution, Ecology and Organismal BiologyThe Ohio State University318 West 12th AvenueColumbusOhio43210
| | - Karen Goodell
- Department of Evolution, Ecology and Organismal BiologyThe Ohio State University1179 University DriveNewarkOhio43055
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31
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Murphy JT, Johnson MP. A theoretical analysis of the Allee effect in wind-pollinated cordgrass plant invasions. Theor Popul Biol 2015; 106:14-21. [DOI: 10.1016/j.tpb.2015.10.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 08/23/2015] [Accepted: 10/10/2015] [Indexed: 10/22/2022]
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32
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Olivieri I, Tonnabel J, Ronce O, Mignot A. Why evolution matters for species conservation: perspectives from three case studies of plant metapopulations. Evol Appl 2015; 9:196-211. [PMID: 27087848 PMCID: PMC4780382 DOI: 10.1111/eva.12336] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Accepted: 09/30/2015] [Indexed: 01/16/2023] Open
Abstract
We advocate the advantage of an evolutionary approach to conservation biology that considers evolutionary history at various levels of biological organization. We review work on three separate plant taxa, spanning from one to multiple decades, illustrating extremes in metapopulation functioning. We show how the rare endemics Centaurea corymbosa (Clape Massif, France) and Brassica insularis in Corsica (France) may be caught in an evolutionary trap: disruption of metapopulation functioning due to lack of colonization of new sites may have counterselected traits such as dispersal ability or self‐compatibility, making these species particularly vulnerable to any disturbance. The third case study concerns the evolution of life history strategies in the highly diverse genus Leucadendron of the South African fynbos. There, fire disturbance and the recolonization phase after fires are so integral to the functioning of populations that recruitment of new individuals is conditioned by fire. We show how past adaptation to different fire regimes and climatic constraints make species with different life history syndromes more or less vulnerable to global changes. These different case studies suggest that management strategies should promote evolutionary potential and evolutionary processes to better protect extant biodiversity and biodiversification.
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Affiliation(s)
- Isabelle Olivieri
- Institut des Sciences de l'Evolution Université Montpellier CNRS IRD EPHE CC65 Place Eugène Bataillon, 34095, Montpellier cedex 5 France
| | - Jeanne Tonnabel
- Institut des Sciences de l'Evolution Université Montpellier CNRS IRD EPHE CC65 Place Eugène Bataillon, 34095, Montpellier cedex 5 France; Department of Ecology and Evolution Le Biophore UNIL-SORGE University of Lausanne Lausanne Switzerland
| | - Ophélie Ronce
- Institut des Sciences de l'Evolution Université Montpellier CNRS IRD EPHE CC65 Place Eugène Bataillon, 34095, Montpellier cedex 5 France
| | - Agnès Mignot
- Institut des Sciences de l'Evolution Université Montpellier CNRS IRD EPHE CC65 Place Eugène Bataillon, 34095, Montpellier cedex 5 France
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An endangered reed, Arundo donaciformis, in a dynamic urban environment: The need for interdisciplinary conservation proposals. J Nat Conserv 2015. [DOI: 10.1016/j.jnc.2015.03.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Anic V, Henríquez CA, Abades SR, Bustamante RO. Number of conspecifics and reproduction in the invasive plant Eschscholzia californica (Papaveraceae): is there a pollinator-mediated Allee effect? PLANT BIOLOGY (STUTTGART, GERMANY) 2015; 17:720-727. [PMID: 25496191 DOI: 10.1111/plb.12293] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Accepted: 12/03/2014] [Indexed: 06/04/2023]
Abstract
The component Allee effect has been defined as 'a positive relationship between any measure of individual fitness and the number or density of conspecifics'. Larger plant populations or large patches have shown a higher pollinator visitation rate, which may give rise to an Allee effect in reproduction of the plants. We experimentally tested the effect of number of conspecifics on reproduction and pollinator visitation in Eschscholzia californica Cham., an invasive plant in Chile. We then built patches with two, eight and 16 flowering individuals of E. californica (11 replicates per treatment) in an area characterised by dominance of the study species. We found that E. californica exhibits a component Allee effect, as the number of individuals of this species has a positive effect on individual seed set. However, individual fruit production was not affected by the number of plants examined. Pollinator visitation rate was also independent of the number of plants, so this factor would not explain the Allee effect. This rate was positively correlated with the total number of flowers in the patches. We also found that the number of plants did not affect the seed mass or proportion of germinated seeds in the patches. Higher pollen availability in patches with 16 plants and pollination by wind could explain the Allee effect. The component Allee effect identified could lead to a weak demographic Allee effect that might reduce the rate of spread of E. californica. Knowledge of this would be useful for management of this invasive plant in Chile.
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Affiliation(s)
- V Anic
- Department of Ecological Sciences, University of Chile, Ñuñoa, Chile; Institute of Ecology and Biodiversity (IEB), University of Chile, Ñuñoa, Chile
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35
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Pannell JR. Evolution of the mating system in colonizing plants. Mol Ecol 2015; 24:2018-37. [DOI: 10.1111/mec.13087] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 01/12/2015] [Accepted: 01/15/2015] [Indexed: 12/16/2022]
Affiliation(s)
- John R. Pannell
- Department of Ecology and Evolution; University of Lausanne; Biophore Building 1015 Lausanne Switzerland
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36
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Budroni MA, Farris E, Zirulia A, Pisanu S, Filigheddu R, Rustici M. Evidence for age-structured depensation effect in fragmented plant populations: The case of the Mediterranean endemic Anchusa sardoa (Boraginaceae). ECOLOGICAL COMPLEXITY 2014. [DOI: 10.1016/j.ecocom.2014.09.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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37
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Kim ES, Zaya DN, Fant JB, Ashley MV. Genetic factors accelerate demographic decline in rare Asclepias species. CONSERV GENET 2014. [DOI: 10.1007/s10592-014-0663-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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38
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Selwood KE, McGeoch MA, Mac Nally R. The effects of climate change and land-use change on demographic rates and population viability. Biol Rev Camb Philos Soc 2014; 90:837-53. [PMID: 25155196 DOI: 10.1111/brv.12136] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 07/08/2014] [Accepted: 07/14/2014] [Indexed: 11/30/2022]
Abstract
Understanding the processes that lead to species extinctions is vital for lessening pressures on biodiversity. While species diversity, presence and abundance are most commonly used to measure the effects of human pressures, demographic responses give a more proximal indication of how pressures affect population viability and contribute to extinction risk. We reviewed how demographic rates are affected by the major anthropogenic pressures, changed landscape condition caused by human land use, and climate change. We synthesized the results of 147 empirical studies to compare the relative effect size of climate and landscape condition on birth, death, immigration and emigration rates in plant and animal populations. While changed landscape condition is recognized as the major driver of species declines and losses worldwide, we found that, on average, climate variables had equally strong effects on demographic rates in plant and animal populations. This is significant given that the pressures of climate change will continue to intensify in coming decades. The effects of climate change on some populations may be underestimated because changes in climate conditions during critical windows of species life cycles may have disproportionate effects on demographic rates. The combined pressures of land-use change and climate change may result in species declines and extinctions occurring faster than otherwise predicted, particularly if their effects are multiplicative.
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Affiliation(s)
- Katherine E Selwood
- School of Biological Sciences, Monash University, Clayton, Victoria, 3800, Australia
| | - Melodie A McGeoch
- School of Biological Sciences, Monash University, Clayton, Victoria, 3800, Australia
| | - Ralph Mac Nally
- Institute for Applied Ecology, The University of Canberra, Bruce, Australian Capital Territory, 2617, Australia
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Self-incompatibility in Brassicaceae: identification and characterization of SRK-like sequences linked to the S-locus in the tribe Biscutelleae. G3-GENES GENOMES GENETICS 2014; 4:983-92. [PMID: 24939184 PMCID: PMC4065267 DOI: 10.1534/g3.114.010843] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Self-incompatibility (SI) is a genetic system that prevents self-fertilization in many Angiosperms. Although plants from the Brassicaceae family present an apparently unique SI system that is ancestral to the family, investigations at the S-locus responsible for SI have been mostly limited to two distinct lineages (Brassica and Arabidopsis-Capsella, respectively). Here, we investigated SI in a third deep-branching lineage of Brassicaceae: the tribe Biscutelleae. By coupling sequencing of the SI gene responsible for pollen recognition (SRK) with phenotypic analyses based on controlled pollinations, we identified 20 SRK-like sequences functionally linked to 13 S-haplotypes in 21 individuals of Biscutella neustriaca and 220 seedlings. We found two genetic and phylogenetic features of SI in Biscutelleae that depart from patterns observed in the reference Arabidopsis clade: (1) SRK-like sequences cluster into two main phylogenetic lineages interspersed within the many SRK lineages of Arabidopsis; and (2) some SRK-like sequences are transmitted by linked pairs, suggesting local duplication within the S-locus. Strikingly, these features also were observed in the Brassica clade but probably evolved independently, as the two main SRK clusters in Biscutella are distinct from those in Brassica. In the light of our results and of what has been previously observed in other Brassicaceae, we discuss the ecological and evolutionary implications on SI plant populations of the high diversity and the complex dominance relationships we found at the S-locus in Biscutelleae.
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40
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Thrall PH, Encinas-Viso F, Hoebee SE, Young AG. Life history mediates mate limitation and population viability in self-incompatible plant species. Ecol Evol 2014; 4:673-87. [PMID: 24683451 PMCID: PMC3967894 DOI: 10.1002/ece3.963] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 12/19/2013] [Accepted: 01/07/2014] [Indexed: 11/15/2022] Open
Abstract
Genetically controlled self-incompatibility systems represent links between genetic diversity and plant demography with the potential to directly impact on population dynamics. We use an individual-based spatial simulation to investigate the demographic and genetic consequences of different self-incompatibility systems for plants that vary in reproductive capacity and lifespan. The results support the idea that, in the absence of inbreeding effects, populations of self-incompatible species will often be smaller and less viable than self-compatible species, particularly for shorter-lived organisms or where potential fecundity is low. At high ovule production and low mortality, self-incompatible and self-compatible species are demographically similar, thus self-incompatibility does not automatically lead to reduced mate availability or population viability. Overall, sporophytic codominant self-incompatibility was more limiting than gametophytic or sporophytic dominant systems, which generally behaved in a similar fashion. Under a narrow range of conditions, the sporophytic dominant system maintained marginally greater mate availability owing to the production of S locus homozygotes. While self-incompatibility reduces population size and persistence for a broad range of conditions, the actual number of S alleles, beyond that required for reproduction, is important for only a subset of life histories. For these situations, results suggest that addition of new S alleles may result in significant demographic rescue.
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Affiliation(s)
- Peter H Thrall
- CSIRO Plant IndustryGPO Box 1600, Canberra, Australian Capital Territory, 2601, Australia
| | - Francisco Encinas-Viso
- CSIRO Plant IndustryGPO Box 1600, Canberra, Australian Capital Territory, 2601, Australia
| | - Susan E Hoebee
- Department of Botany, La Trobe UniversityBundoora, Victoria, 3086, Australia
| | - Andrew G Young
- CSIRO Plant IndustryGPO Box 1600, Canberra, Australian Capital Territory, 2601, Australia
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41
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Beckman NG, Dybzinski R, Tilman GD. Neighborhoods have little effect on fungal attack or insect predation of developing seeds in a grassland biodiversity experiment. Oecologia 2013; 174:521-32. [PMID: 24085638 DOI: 10.1007/s00442-013-2788-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 09/12/2013] [Indexed: 10/26/2022]
Abstract
Numerous observational studies have documented conspecific negative density-dependence that is consistent with the Janzen-Connell Hypothesis (JCH) of diversity maintenance. However, there have been few experimental tests of a central prediction of the JCH: that removing host-specific enemies should lead to greater increases in per capita recruitment in areas of higher host density or lower relative phylogenetic diversity. Using spatially randomized plots of high and low host biomass in a temperate grassland biodiversity experiment, we treated developing seedheads of six prairie perennials to factorial applications of fungicide and insecticide. We measured predispersal seed production, seed viability, and seedling biomass. Results were highly species-specific and idiosyncratic. Effects of insect seed predators and fungal pathogens on predispersal responses varied with neither conspecific biomass nor phylogenetic diversity, suggesting that-at least at the predispersal stage and for the insect and fungal seed predators we were able to exclude-the JCH is not sufficient to contribute to negative conspecific density-dependence for these dominant prairie species.
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Affiliation(s)
- Noelle G Beckman
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
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42
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Mate limitation in populations of the endangered Convolvulus lineatus L.: A case for genetic rescue? J Nat Conserv 2013. [DOI: 10.1016/j.jnc.2013.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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43
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Firestone JL, Jasieniuk M. Seed production is reduced by small population size in natural populations of the invasive grass Lolium multiflorum. Biol Invasions 2012. [DOI: 10.1007/s10530-012-0248-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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44
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Leducq JB, Siniarsky C, Gosset CC, Godé C, Poiret M, Blondel C, Hautekèete NC, Piquot Y, Poux C, Valentin B, Billiard S, Vekemans X. Intriguing small-scale spatial distribution of chloropastic and nuclear diversity in the endangered plant Biscutella neustriaca (Brassicaceae). CONSERV GENET 2012. [DOI: 10.1007/s10592-012-0426-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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45
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Firestone JL, Jasieniuk M. Small population size limits reproduction in an invasive grass through both demography and genetics. Oecologia 2012; 172:109-17. [DOI: 10.1007/s00442-012-2465-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Accepted: 09/04/2012] [Indexed: 10/27/2022]
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46
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Martén-Rodríguez S, Quesada M, Momen B. Effects of Local Plant Density and Incomplete Dichogamy on the Reproductive Success of the Rare Neotropical Palm Geonoma epetiolata. Biotropica 2012. [DOI: 10.1111/j.1744-7429.2012.00860.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Silvana Martén-Rodríguez
- Departamento de Biología Evolutiva; Instituto de Ecología A.C.; Carretera antigua a Coatepec No. 351; El Haya; Xalapa; Veracruz; 91070; Mexico
| | - Mauricio Quesada
- Centro de Investigaciones en Ecosistemas; Universidad Nacional Autónoma de México; Apartado Postal 27-3 (Xangari); 58089; Morelia; Michoacán; Mexico
| | - Braham Momen
- Environmental Science and Technology Department; University of Maryland; 20742; College Park; MD; U.S.A
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47
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Gates DJ, Nason JD. Flowering asynchrony and mating system effects on reproductive assurance and mutualism persistence in fragmented fig-fig wasp populations. AMERICAN JOURNAL OF BOTANY 2012; 99:757-768. [PMID: 22491002 DOI: 10.3732/ajb.1100472] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
PREMISE OF THE STUDY Plants and animals may experience reproductive Allee effects in fragmented populations, and obligate pollination mutualisms may be especially sensitive to extinction risk via this density-dependent process. In this study we examine how a shift from within-crown reproductive synchrony to asynchrony influences reproductive assurance through contributions to selfing and outcrossing in small, spatially isolated populations of Ficus. METHODS The research focuses on the monoecious fig F. petiolaris and consists of phenological analyses and genetic assessments of selfing and outcrossing for populations located in Baja California's Sonoran Desert. KEY RESULTS Phenological censuses of eight populations revealed within-crown asynchrony in 44% of reproducing trees, with 16% having sufficient overlap of male and female flowering phases to permit selfing via the cycling of pollinating fig wasps within natal trees. In mating system analyses of two of these populations, however, multilocus outcrossing rates (t(m)) were indistinguishable from 1. This result, combined with low levels of inbreeding, indicates selfing to be absent or at best a minor contributor to reproductive assurance. CONCLUSIONS The results indicate that the fitness benefits of within-crown asynchrony lie not with selfing, as commonly asserted, but with increased opportunities for outcross pollen transmission and receipt, changing our understanding of the mechanisms by which reproduction is facilitated and extinction risk minimized in naturally fragmented Ficus populations. Given the role of fig fruit as a keystone food resource in many tropical environments, trait variation leading to reproductive assurance in figs, such as within-crown asynchrony, has broader ecosystem-level implications.
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Affiliation(s)
- Daniel J Gates
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
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48
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Young AG, Broadhurst LM, Thrall PH. Non-additive effects of pollen limitation and self-incompatibility reduce plant reproductive success and population viability. ANNALS OF BOTANY 2012; 109:643-53. [PMID: 22184620 PMCID: PMC3278296 DOI: 10.1093/aob/mcr290] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
BACKGROUND AND AIMS Mating system is a primary determinant of the ecological and evolutionary dynamics of wild plant populations. Pollen limitation and loss of self-incompatibility genotypes can both act independently to reduce seed set and these effects are commonly observed in fragmented landscapes. This study used a simulation modelling approach to assess the interacting effects of these two processes on plant reproductive performance and population viability for a range of pollination likelihood, self-incompatibility systems and S-allele richness conditions. METHODS A spatially explicit, individual-based, genetic and demographic simulation model parameterized to represent a generic self-incompatible, short-lived perennial herb was used to conduct simulation experiments in which pollination probability, self-incompatibility type (gametophytic and sporophytic) and S-allele richness were systematically varied in combination to assess their independent and interacting effects on the demographic response variables of mate availability, seed set, population size and population persistence. KEY RESULTS Joint effects of reduced pollination probability and low S-allele richness were greater than independent effects for all demographic response variables except population persistence under high pollinator service (>50 %). At intermediate values of 15-25 % pollination probability, non-linear interactions with S-allele richness generated significant reductions in population performance beyond those expected by the simple additive effect of each independently. This was due to the impacts of reduced effective population size on the ability of populations to retain S alleles and maintain mate availability. Across a limited set of pollination and S-allele conditions (P = 0·15 and S = 20) populations with gametophytic SI showed reduced S-allele erosion relative to those with sporophytic SI, but this had limited effects on individual fecundity and translated into only modest increases in population persistence. CONCLUSIONS Interactions between pollen limitation and loss of S alleles have the potential to significantly reduce the viability of populations of a few hundred plants. Population decline may occur more rapidly than expected when pollination probabilities drop below 25 % and S alleles are fewer than 20 due to non-additive interactions. These are likely to be common conditions experienced by plants in small populations in fragmented landscapes and are also those under which differences in response between gameptophytic and sporophtyic systems are observed.
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Hoebee SE, Angelone S, Csencsics D, Määttänen K, Holderegger R. Diversity of S-alleles and mate availability in 3 populations of self-incompatible wild pear (Pyrus pyraster). ACTA ACUST UNITED AC 2011; 103:260-7. [PMID: 22194625 DOI: 10.1093/jhered/esr126] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Small populations of self-incompatible plants may be expected to be threatened by the limitation of compatible mating partners (i.e., S-Allee effect). However, few empirical studies have explicitly tested the hypothesis of mate limitation in small populations of self-incompatible plants. To do so, we studied wild pear (Pyrus pyraster), which possesses a gametophytic self-incompatibility system. We determined the S-genotypes in complete samplings of all adult trees from 3 populations using a PCR-RFLP approach. We identified a total of 26 different S-alleles, homologous to S-alleles of other woody Rosaceae. The functionality of S-alleles and their Mendelian inheritance were verified in artificial pollination experiments and investigations of pollen tube growth. The smallest population (N = 8) harbored 9 different S-alleles and showed a mate availability of 92.9%, whereas the 2 larger populations harbored 18 and 25 S-alleles and exhibited mate availabilities of 98.4% and 99.2%, respectively. Therefore, we conclude that even small populations of gametophytic self-incompatible plants may exhibit high diversity at the S-locus and are not immediately threatened owing to reduced mate availability.
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Affiliation(s)
- S E Hoebee
- WSL Swiss Federal Research Institute, Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland
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Ridley CE, Hangelbroek HH, Wagenius S, Stanton-Geddes J, Shaw RG. The effect of plant inbreeding and stoichiometry on interactions with herbivores in nature: Echinacea angustifolia and its specialist aphid. PLoS One 2011; 6:e24762. [PMID: 21935460 PMCID: PMC3172291 DOI: 10.1371/journal.pone.0024762] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 08/17/2011] [Indexed: 11/19/2022] Open
Abstract
Fragmentation of once widespread communities may alter interspecific interactions by changing genetic composition of interacting populations as well as their abundances and spatial distributions. In a long-term study of a fragmented population of Echinacea angustifolia, a perennial plant native to the North American prairie, we investigated influences on its interaction with a specialist aphid and tending ants. We grew plant progeny of sib-matings (I), and of random pairings within (W) and between (B) seven remnants in a common field within 8 km of the source remnants. During the fifth growing season, we determined each plant's burden of aphids and ants, as well as its size and foliar elemental composition (C, N, P). We also assayed composition (C, N) of aphids and ants. Early in the season, progeny from genotypic classes B and I were twice as likely to harbor aphids, and in greater abundance, than genotypic class W; aphid loads were inversely related to foliar concentration of P and positively related to leaf N and plant size. At the end of the season, aphid loads were indistinguishable among genotypic classes. Ant abundance tracked aphid abundance throughout the season but showed no direct relationship with plant traits. Through its potential to alter the genotypic composition of remnant populations of Echinacea, fragmentation can increase Echinacea's susceptibility to herbivory by its specialist aphid and, in turn, perturb the abundance and distribution of aphids.
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Affiliation(s)
- Caroline E. Ridley
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Helen H. Hangelbroek
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Stuart Wagenius
- Division of Plant Science and Conservation, Chicago Botanic Garden, Glencoe, Illinois, United States of America
| | - John Stanton-Geddes
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Ruth G. Shaw
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, Minnesota, United States of America
- * E-mail:
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