title: Rapid genetic restoration of a keystone species exhibiting delayed demographic response.
abstract: Genetic founder effects are often expected when animals colonize restored habitat in fragmented landscapes, but empirical data on genetic responses to restoration are limited. We examined the genetic response of banner-tailed kangaroo rats (Dipodomys spectabilis) to landscape-scale grassland restoration in the Chihuahuan Desert of New Mexico, USA. Dipodomys spectabilis is a grassland specialist and keystone species. At sites treated with herbicide to remove shrubs, colonization by D. spectabilis is slow and populations persist at low density for ≥10 years (≥6 generations). Persistence at low density and low gene flow may cause strong founder effects. We compared genetic structure of D. spectabilis populations between treated sites and remnant grasslands, and we examined how the genetic response to restoration depended on treatment age, area, and connectivity to source populations. Allelic richness and heterozygosity were similar between treated sites and remnant grasslands. Allelic richness at treated sites was greatest early in the restoration trajectory, and genetic divergence did not differ between recently colonized and established populations. These results indicated that founder effects during colonization of treated sites were weak or absent. Moreover, our results suggested founder effects were not mitigated by treatment area or connectivity. Dispersal is negatively density-dependent in D. spectabilis, and we hypothesize that high gene flow may occur early in the restoration trajectory when density is low. Our study shows genetic diversity can be recovered more rapidly than demographic components of populations after habitat restoration and that founder effects are not inevitable for animals colonizing restored habitat in fragmented landscapes.
authors.affiliation: Department of Biology, Hobart and William Smith Colleges, Geneva, NY, 14456, USA.
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: Cosentino
authors.affiliation: Department of Natural Resources and Environmental Sciences, University of Illinois, Urbana, IL, 61801, USA.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Schooley
authors.affiliation: USDA-ARS Jornada Experimental Range, New Mexico State University, MSC 3JER, Box 30003, Las Cruces, NM, 88003, USA.
authors.forename: Brandon T
authors.initials: BT
authors.lastname: Bestelmeyer
authors.affiliation: Department of Biology, Hobart and William Smith Colleges, Geneva, NY, 14456, USA.
authors.forename: Alison J
authors.initials: AJ
authors.lastname: McCarthy
authors.affiliation: Department of Natural Resources and Environmental Sciences, University of Illinois, Urbana, IL, 61801, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Sierzega
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D003247:Conservation of Natural Resources; D004173:Dipodomys / Q000235:genetics*; D017753:Ecosystem; D052918:Environmental Restoration and Remediation; D018703:Founder Effect; D051456:Gene Flow; D014644:Genetic Variation; D005828:Genetics, Population; D065948:Grassland; D016014:Linear Models; D018895:Microsatellite Repeats; D008957:Models, Genetic; D009516:New Mexico; D011157:Population Dynamics; D017422:Sequence Analysis, DNA
keywords: Dipodomys spectabilis; conservation genetics; density dependence; dispersal; ecological restoration; founder effects