title: Comparative evaluation of potential indicators and temporal sampling protocols for monitoring genetic erosion.
abstract: Genetic biodiversity contributes to individual fitness, species' evolutionary potential, and ecosystem stability. Temporal monitoring of the genetic status and trends of wild populations' genetic diversity can provide vital data to inform policy decisions and management actions. However, there is a lack of knowledge regarding which genetic metrics, temporal sampling protocols, and genetic markers are sufficiently sensitive and robust, on conservation-relevant timescales. Here, we tested six genetic metrics and various sampling protocols (number and arrangement of temporal samples) for monitoring genetic erosion following demographic decline. To do so, we utilized individual-based simulations featuring an array of different initial population sizes, types and severity of demographic decline, and DNA markers [single nucleotide polymorphisms (SNPs) and microsatellites] as well as decline followed by recovery. Number of alleles markedly outperformed other indicators across all situations. The type and severity of demographic decline strongly affected power, while the number and arrangement of temporal samples had small effect. Sampling 50 individuals at as few as two time points with 20 microsatellites performed well (good power), and could detect genetic erosion while 80-90% of diversity remained. This sampling and genotyping effort should often be affordable. Power increased substantially with more samples or markers, and we observe that power of 2500 SNPs was nearly equivalent to 250 microsatellites, a result of theoretical and practical interest. Our results suggest high potential for using historic collections in monitoring programs, and demonstrate the need to monitor genetic as well as other levels of biodiversity.
authors.affiliation: National Institute for Mathematical and Biological Synthesis (NIMBioS), University of Tennessee Knoxville, TN, USA ; Department of Life Science, Università di Ferrara Ferrara, Italy.
authors.forename: Sean
authors.initials: S
authors.lastname: Hoban
authors.affiliation: Naturalis Biodiversity Center Leiden, the Netherlands.
authors.forename: Jan A
authors.initials: JA
authors.lastname: Arntzen
authors.affiliation: School of Biosciences, Cardiff University Cardiff, Wales, UK.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Bruford
authors.affiliation: Estación Biológica de Doñana (EBD-CSIC) Seville, Spain.
authors.forename: José A
authors.initials: JA
authors.lastname: Godoy
authors.affiliation: Durham University Durham, UK.
authors.forename: A
authors.initials: A
authors.lastname: Rus Hoelzel
authors.affiliation: University Freiburg Freiburg, Germany.
authors.forename: Gernot
authors.initials: G
authors.lastname: Segelbacher
authors.affiliation: Estación Biológica de Doñana (EBD-CSIC) Seville, Spain.
authors.forename: Carles
authors.initials: C
authors.lastname: Vilà
authors.affiliation: Department of Life Science, Università di Ferrara Ferrara, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Bertorelle
keywords: alpha diversity; conservation biology; convention on biological diversity; microsatellites; population genetic; simulation; single nucleotide polymorphism; temporal sampling