Sarah Duncan

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). Naive 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 b 12 days. Including all radiotagged pocket gophers, daily survival of soft-released animals (S = 0.990) was intermediate between hard-released (S= 0.986) and controls (S= 0.993), and only hard-released was lower than controls. Using only individuals that survived greater than 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 three 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.

Genetic connectivity lies at the heart of evolutionary theory, and landscape genetics has rapidly advanced to understand how gene flow can be impacted by the environment. Isolation by landscape resistance, often inferred through the use of circuit theory, is increasingly identified as being critical for predicting genetic connectivity across complex landscapes. Yet landscape impediments to migration can arise from fundamentally different processes, such as landscape gradients causing directional migration and mortality during migration, which can be challenging to address. Spatial absorbing Markov chains (SAMC) have been introduced to understand and predict these (and other) processes affecting connectivity in ecological settings, but the relationship of this framework to landscape genetics remains unclear. Here, we relate the SAMC to population genetics theory, provide simulations to interpret the extent to which the SAMC can predict genetic metrics and demonstrate how the SAMC can be applied to genomic data using an example with an endangered species, the Panama City crayfish Procambarus econfinae, where directional migration is hypothesized to occur. The use of the SAMC for landscape genetics can be justified based on similar grounds to using circuit theory, as we show how circuit theory is a special case of this framework. The SAMC can extend circuit-theoretic connectivity modelling by quantifying both directional resistance to migration and acknowledging the difference between migration mortality and resistance to migration. Our empirical example highlights that the SAMC better predicts population structure than circuit theory and least-cost analysis by acknowledging asymmetric environmental gradients (i.e. slope) and migration mortality in this species. These results provide a foundation for applying the SAMC to landscape genetics. This framework extends isolation-by-resistance modelling to account for some common processes that can impact gene flow, which can improve predicting genetic connectivity across complex landscapes.

We assessed the macrogeographic and neuroendocrine correlates of behavioral variation exhibited by juveniles, an important life stage for dispersal, across the expansive range of the wood frog. By rearing animals from eggs in a common garden then using a novel environment test, we uniquely demonstrated differential expression of juvenile behaviors among 16 populations spanning 8 degrees latitude. On the individual level, cluster analysis indicated three major behavior profiles and principal component analysis resolved four unique axes of behavior, including escape, foraging, food intake, feeding efficiency. We found that increased escape behavior was associated with lower adrenocorticotropic hormone (ACTH)-induced circulating corticosterone (CORT) levels, however, foraging and food intake behaviors were not associated with either resting or ACTH-induced CORT. At the population level, the expression of foraging behaviors increased with latitude while food intake behaviors declined with latitude, which raised several hypotheses of eco-evolutionary processes likely driving this variation. Given that these behaviors covary along the same ecological gradient as locally adapted developmental traits, genomic studies in this species could provide deep insights into how HPA/I activity is associated with the eco-evolutionary processes that structure intraspecific variation in morphology and behavior.

Pocket gophers provide vital ecosystem services; however, species like the southeastern pocket gopher (Geomys pinetis), endemic to the southeastern United States, are declining. Long-term conservation of this species requires greater understanding of its habitat characteristics. Our objective here was to determine habitat features associated with southeastern pocket gopher occurrence at the local (100 ha) and home-range (0.09 ha) scales. We assessed occurrence and carried out vegetation surveys at 177 sites across the species' range during the growing season (March–September) 2016–2017. At the local scale, we found a negative relationship between occurrence and groundcover height and a quadratic relationship with canopy closure. At the home-range scale, occurrence was positively related to grass groundcover and had a quadratic relationship with canopy closure. Restoration of southeastern pocket gopher habitat should focus on creating or maintaining areas with intermediate canopy (∼45–55%) and an understory dominated by grasses and forbs.

Biofluorescence in mammal pelage is considered rare, but has been documented in multiple taxa in recent years. Herein, we provide the first observations of biofluorescence in fossorial mammals. We documented biofluorescence in live Geomys pinetis (southeastern pocket gopher) and in museum specimens of four additional geomyid species. Although unknown, the adaptive significance of biofluorescence in pocket gophers is likely similar to that documented in terrestrial and arboreal species previously, including communication or predator evasion.