Figure 1 - uploaded by J.T. Pynne
Content may be subject to copyright.
Locations of Southeastern Pocket Gopher capture and relocation sites at Plant Vogtle, Burke County, GA, 2010-2011. Inset map shows the historical species distribution.
Source publication
Geomys pinetis (Southeastern Pocket Gopher) is absent from much of its historic distribution due to reductions in suitable habitat, which consists largely of open Pinus (pine) systems. Restored open pine habitat represents an opportunity to reestablish Southeastern Pocket Gophers into areas within their historic distribution through translocation....
Context in source publication
Similar publications
Geomys pinetis (Southeastern Pocket Gopher) is absent from much of its historic
distribution due to reductions in suitable habitat, which consists largely of open Pinus (pine) systems. Restored open pine habitat represents an opportunity to reestablish Southeastern Pocket Gophers into areas within their historic distribution through translocation....
Citations
... We sought to determine whether the genomic SNP data would reflect deep divergence at the highest hierarchical level (i.e., previous phylogenetic evidence for an east-west split). Second, we predicted that the habitat specificity and a presumed low vagility of G. pinetis (Hickman and Brown 1973;Warren et al. 2017b;Pynne et al. 2019a), combined with increased fragmentation of longleaf pine savannas (Noss et al. 1995;Frost 2007) would result in a signature of reflecting a prominent role for genetic drift between local populations, as has been found in other pocket gopher species (Penney and Zimmerman 1976;Patton and Yang 1977;Patton and Feder 1981;Welborn and Light 2014). Demographic factors such as limited population connectivity and small home ranges will be reflected in neutral signatures of genetic variation, whereas outlier SNP loci may reflect environmental variation or gradients. ...
... In agreement with previous genetic work (Avise et al. 1979;Sudman et al. 2006;Chambers et al. 2009;Soto-Centeno et al. 2013), our results provide strong evidence that southeastern pocket gophers consist of two distinct lineages that have been reproductively isolated for an extended period (i.e., likely since the Pleistocene) and may have undergone some degree of adaptive divergence. We also found support for our prediction that the habitat specificity and a presumed low vagility of G. pinetis (Hickman and Brown 1973;Warren et al. 2017b;Pynne et al. 2019a), combined with increased fragmentation of longleaf pine savannas (Noss et al. 1995;Frost 2007), resulted in a signature of strong genetic drift, as has been found in other pocket gopher species (Penney and Zimmerman 1976;Patton and Yang 1977;Patton and Feder 1981;Welborn and Light 2014). Factors such as limited population connectivity and small home ranges will be reflected in neutral signatures of genetic variation, whereas outlier SNP loci may reflect environmental variation or gradients (Soto-Centeno et al. 2013). ...
Knowledge of the population genetic structure and diversity of at-risk species is essential to accurately evaluate population viability and define units for conservation and management. The southeastern pocket gopher (Geomys pinetis) is a fossorial rodent native to the imperiled longleaf pine savannas of the southeastern United States. Its recent decline has made it a species of ‘high conservation concern’ by state agencies. Previous phylogenetic analyses suggested two distinct lineages within the species occurring east (G. p. pinetis) and west (G. p. mobilensis) of the Apalachicola-Chattahoochee-Flint River (ACF) Basin, a phylogeographic break for many species. However, little is known about the genetic substructure within each region. We examined neutral and putatively adaptive variation in 9373 single nucleotide polymorphisms (SNPs) to assess the extent of genetic structure across the species' geographic range. We confirmed significant genetic divergence of populations east–west of the ACF Basin, predating the Last Glacial Maximum, supporting the presence of two evolutionary independent lineages. Our results indicate additional strong genetic substructuring within each lineage and possible non-neutral variation across latitudes. Given the high degree of genetic differentiation and lack of evidence for secondary contact among populations within the ACF Basin, we recommend that G. pinetis be managed as two conservation units corresponding to distinct lineages representing G. pinetis and G. mobiliensis.
... Soft-released animals typically remain closer to the release site, a primary factor contributing to translocation success. Although numerous techniques have been used successfully with terrestrial mammals, soft-release protocols for fossorial species have received less attention (Truett et al. 2001;Hansler et al. 2017;Pynne et al. 2019). ...
... Hansler et al. (2017) observed low mortality in translocated maritime pocket gophers (Geomys personatus maritimus Davis) and that individuals generally reamined near the release area, indicating translocation as a potential management option. Pynne et al. (2019) observed increased movements by translocated southeastern pocket gophers leading to high predation rates. They suggested that soft-release approaches to limit aboveground movements may lower predation risk and increase translocation success. ...
... We transported captured animals individually in 38 L glass aquaria partially filled with soil and roots collected from their capture areas. We surgically implanted 3G VHF transmitters (148-149 MHz; Model SOPI-2070; Wildlife Materials Inc., Murphysboro, IL, U.S.A.) with an estimated 120-day transmitter battery life into the abdominal cavities of adult and subadult (>100 g) individuals (Hansler et al. 2017;Warren et al. 2017b;Pynne et al. 2019). The first five surgeries were conducted at the University of Georgia School of Veterinary Medicine up to 24 hours after capture under the supervision and training of a veterinarian. ...
The longleaf pine (Pinus palustris Mill.) savanna ecosystem in North America has declined by 97% from its historic range and its restoration is a conservation priority. The southeastern pocket gopher (Geomys pinetis), an ecosystem engineer in longleaf pine savannas, is absent from most of its historic range. Translocation of pocket gophers may be needed to reestablish ecosystem services of restored longleaf savannas. To determine translocation feasibility, we quantified survival, site fidelity, and homing of pocket gophers translocated using soft releases (with a starter burrow system; n = 13), hard releases (without a starter burrow system; n = 17), or released into their own burrows (control, n = 10). Naïve survival was 46% and 35% for soft‐ and hard‐released individuals, respectively, and 80% for controls. Most mortalities of translocated individuals (75.0%) occurred within 12 days. Including all radiotagged pocket gophers, daily survival of soft‐released animals (Ŝ = 0.990) was intermediate between hard‐released (Ŝ = 0.986) and controls (Ŝ = 0.993), and only hard‐released was lower than controls. Using only individuals that survived >14 days, we found no difference in daily survival. Site fidelity was low, with 70% of translocated pocket gophers making aboveground movements away from release point. However, soft‐released individuals stayed at the release point 3 times longer than hard‐released animals. No pocket gopher exhibited homing. Our results suggest translocation has potential for establishing pocket gopher populations into restored longleaf pine savannas and that mitigating mortality during establishment will increase the likelihood of success. This article is protected by copyright. All rights reserved.
Context
Understanding genetic structure at multiple spatial scales and identifying drivers of genetic isolation are important for developing comprehensive conservation plans including for grassland conservation efforts. However, few studies account for multiple genetic isolation processes nor partition genetic variance among these processes.
Objectives
We assess key processes that can create spatial genetic patterns including isolation by barrier (IBB), isolation by distance (IBD), and isolation by environment (IBE) for a widespread pocket gopher species (Geomys bursarius) and a spatially restricted subspecies (Geomys bursarius illinoensis). We further partition genetic variation to each isolating effect and identify genetic variation that was shared between processes.
Methods
We used seven microsatellites to determine spatial genetic clustering and identify environmental factors impacting genetic similarities. Then, we used redundancy analysis to partition variance explained by IBB, IBD, and IBE.
Results
Major rivers including the Mississippi River acted as barriers and explained the most genetic variation across the species. In contrast, IBD explained the most genetic variation for G. b. illinoensis. Gophers had genetic associations to soil sand percent and soil color, but IBE uniquely explained a small amount of genetic structure for G. bursarius, with additional variation shared with other isolating processes.
Conclusions
Gopher genetic structure resulted from barriers, distance, and environmental factors at the species range as well as for a subspecies’ region, but the relative amount of genetic variance assigned to unique isolating processes differed between scales. Delineation of conservation units should consider major rivers as natural boundaries, and finer-scale management should identify and protect areas close to source populations with similar soil friability. Our study exemplifies how analyzing gene flow at rangewide and regional scales can aid managers in developing localized strategies that fit within broader conservation units.
The biogeographic history of the Chihuahuan Desert is complex, driven by numerous physiographic events and climatic changes. This dynamic history would have influenced the flora and fauna of the region including the desert pocket gopher, Geomys arenarius , a subterranean rodent endemic to the northern Chihuahuan Desert. G . arenarius is restricted to sandy soils and are considered to have a disjunct distribution. Two subspecies are recognized: G . a . arenarius and G . a . brevirostris . We used multilocus nuclear (amplified fragment length polymorphisms) and mitochondrial DNA (ND2) sequence data to uncover patterns of genetic diversity within and among populations of G . arenarius . We evaluated correspondence of genetic patterns to traditionally accepted subspecies boundaries, mapped the distribution of potentially suitable soils to identify barriers or corridors to dispersal and to guide future survey efforts, provided evidence that could be used to recognize distinct population segments, and quantified genetic diversity within populations. Both datasets were largely concordant and demonstrated hierarchical patterns of genetic divergence. The greatest divergence was consistent with the two recognized subspecies. Mapping of potentially habitable soils revealed likely barriers to dispersal contributing to the allopatric pattern of geographic distribution and areas, which may be occupied by G . arenarius but not yet documented. Because G . arenarius is restricted to soils with high sand content, and these habitable soils are disjunct within the region occupied by this species, historical factors that impacted soil deposition and deflation likely contributed to the observed patterns of genetic divergence. Genetic diversity was higher within populations of the southern subspecies ( G . a . arenarius ) compared to G . a . brevirostris . This may be due to a greater availability of continuous suitable soils within the range of G . a . arenarius or higher density due to greater food availability (currently or historically)—both of which could allow for a higher effective population size.
Animals living underground deal with multiple physiological challenges, such as hypoxia and hypercarbia, but may have reduced thermoregulation demands because of the more stable underground microclimate. Southeastern pocket gophers (Geomys pinetis Rafinesque) occur in the fire-adapted, open-pine forests of the southeastern Atlantic Coastal Plain where prescribed fire is commonly used to manage understory vegetation. They are almost exclusively fossorial, and their tunnels provide ecological services, including shelter, for a suite of commensal vertebrates and invertebrates. To quantify potential thermoregulation benefits of southeastern pocket gopher tunnels, we compared temperatures in active tunnels (n ¼ 31) to aboveground temperatures during winter (December 2018-February 2019), and to aboveground temperatures during prescribed fire events (n ¼ 16) occurring in spring (March-May 2019). During winter, tunnels provided a more stable thermal environment (average range ¼ 6.5 6 0.8 C; mean 6 SE) relative to aboveground (average range ¼ 24.8 6 1.8 C) temperatures. Similarly, mean tunnel temperature range (2.05 6 0.5 C) was significantly narrower than aboveground temperature range associated with fire events (497.0 6 101.4 C). Clearly, tunnels provide a stable thermal environment for pocket gophers and commensals that use their tunnel systems.
