Experimental translocation for restoration of an ecosystem engineer

Abstract

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 hardreleased 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 ( b S = 0.990) was intermediate between hard-released ( b S = 0.986) and controls ( b 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.