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Abstract Detail

Reasons for Rarity? Exploring Acclimatory and Adaptive Constraints to Commonness

Anderson, Jill [1], Boyd, Jennifer [2], Cruse-Sanders, Jennifer [3], Brzyski, Jessica [4], Baskauf, Carol [5].

Eco-evolutionary consequences of rarity.

Species differ dramatically in their relative abundance, and various eco-evolutionary factors can constrain the prevalence of some species. Rare species often have low local abundance or restricted geographic distributions. In addition, some species are rare because they are adapted to specialized habitats. Here, we evaluated the genetic, fitness and phenotypic consequences of rarity through phylogenetically-controlled meta-analyses of field and laboratory studies that contrasting rare and common congeneric species of native plants. To assess whether rare species maintain lower genetic variation than common congeners, we compiled a dataset of 34 studies from 1994 - present, which used molecular markers (e.g., allozymes, microsatellites) to compare population genetic parameters across rare and common congeners. As predicted, rare species had significantly lower genetic diversity than common species, in terms of the percentage of loci that are polymorphic, the number of alleles per locus, and the observed heterozygosity. In addition, concordant with expectations, rare species had significantly greater rates of inbreeding (FIS) than common species. We detected no signature of rarity on population genetic differentiation (FST), but this lack of pattern could have been an artifact of low sample size (only 4 studies had FST values for rare and common species). To evaluate the eco-evolutionary effects of rarity, we extracted data from 96 studies from 1978-present that quantified fitness or functional traits of rare and common congeners. We found that species with restricted local abundance have reduced fitness and growth rates relative to their abundant congeners.

Based on our review of the literature, we make several recommendations for future studies. For one, we call for additional studies that contrast phenotypic plasticity in common and rare species using robust quantitative genetic approaches. Additionally, if rarity is driven by specialization to rare habitat types, reciprocal transplant studies need to expose rare and common species to both rare and common source habitats. If habitat specificity underlies rarity additional studies could evaluate which aspect of the abiotic or biotic environment causes this restriction. For example, are rare species restricted to marginal habitats because they are poor competitors? In this talk, we make concrete recommendations for additional studies to disentangle the mechanisms contributing to rarity.

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1 - University of Georgia, Genetics, Athens, GA, 30602, USA
2 - University Of Tennessee At Chattanooga, Dept 2653, 615 McCallie Avenue, Chattanooga, TN, 37403, United States
3 - University Of Georgia, State Botanical Garden Of Georgia, 2450 South Milledge Ave., Athens, GA, 30605, United States
4 - Seton Hill University, Biology, 1 Seton Hill Dr, Box 448F, Greensburg, PA, 15601, United States
5 - Biology, 681 Summer St., Clarksville, TN, 37040, United States


Presentation Type: Colloquium Presentations
Session: C06, Reasons for Rarity? Exploring Acclimatory and Adaptive Constraints to Commonness
Location: /
Date: Wednesday, July 21st, 2021
Time: 3:15 PM(EDT)
Number: C06002
Abstract ID:1116
Candidate for Awards:None

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