Michael E. Dorcas

Recent years have seen a substantial increase in the number of snake invasions. Snakes represent a particularly alarming emerging threat as damaging, but poorly understood, invasive predators (Kraus 2009). The most well-studied snake invasion is that of the brown tree snake (Boiga irregularis) in Guam (see Chapter 7). Accidental introduction of brown tree snakes to Guam shortly after World War II resulted in extirpation of over 50% of the island's native breeding birds and several lizards (Savidge 1987), with cascading effects on invertebrate communities and vegetation dynamics (Mortensen et al. 2008; Caves et al. 2013). Several other snake invaders have been introduced elsewhere, most as a result of the reptile pet trade. Burmese pythons (Python molurus bivittatus), northern African pythons (Python sebae), and boa constrictors (Boa constrictor) are now locally established in Florida (Snow et al. 2007). Boa constrictors are also established on the islands of Cozumel, Aruba, and Puerto Rico (Martínez-Morales and Cuaron 1999; Rogers et al. 2012; Romero et al. 2009). Finally, three species of water snakes (Nerodia) are established in California (Rose and Todd 2014), and most recently, California kingsnakes (Lampropeltis getula) on the Canary Islands (R. Reed, pers. comm.).

Relationships between behavioral regulation, environmental temperatures, and physiological tolerance are critical to conservation policy; however, these relationships may not be consistent among sister taxa. A species geographic range is influenced by various factors including physiological tolerance to temperature change. In this study, we investigated the effects of temperature variation on thermal preference and standard metabolic rates (SMR) of two species of larval salamanders, Eurycea cirrigera (Southern Two-Lined Salamander) and Eurycea wilderae (Blue Ridge Two-Lined Salamander). These species share similar life histories, but E. cirrigera is broadly distributed and E. wilderae occupies a smaller range. We measured SMR using volume of oxygen consumption during closed-circuit respirometery trials conducted at 5°C increments between 5°C and 25°C. Standard metabolic rates were influenced by temperature, with a range of temperature-independent SMRs observed at those temperatures above each spe...

Conservation practitioners must contend with an increasing array of threats that affect biodiversity. Citizen scientists can provide timely and expansive information for addressing these threats across large scales, but their data may contain sampling biases. We used randomization procedures to account for possible sampling biases in opportunistically reported citizen science data to identify species’ sensitivities to human land use. We analyzed 21,044 records of 143 native reptile and amphibian species reported to the Carolina Herp Atlas from North Carolina and South Carolina between 1 January 1990 and 12 July 2014. Sensitive species significantly associated with natural landscapes were 3.4 times more likely to be legally protected or treated as of conservation concern by state resource agencies than less sensitive species significantly associated with human‐dominated landscapes. Many of the species significantly associated with natural landscapes occurred primarily in habitats that had been nearly eradicated or otherwise altered in the Carolinas, including isolated wetlands, longleaf pine savannas, and Appalachian forests. Rare species with few reports were more likely to be associated with natural landscapes and 3.2 times more likely to be legally protected or treated as of conservation concern than species with at least 20 reported occurrences. Our results suggest that opportunistically reported citizen science data can be used to identify sensitive species and that species currently restricted primarily to natural landscapes are likely at greatest risk of decline from future losses of natural habitat. Our approach demonstrates the usefulness of citizen science data in prioritizing conservation and in helping practitioners address species declines and extinctions at large extents.

Diamondback terrapins (Malaclemys terrapin) have experienced declines throughout their range, and accidental mortality in crab pots is a significant conservation concern. To minimize the risk of terrapins entering crab pots, researchers have suggested the use of bycatch reduction devices (BRDs) to reduce the size of crab pot openings and thereby exclude terrapins from entering crab pots. Despite these recommendations, few studies have observed terrapin interactions with BRDs and effectively evaluated the efficacy of these devices at preventing the entry of terrapins into pots. The objective of this study was to determine the effect of BRD presence and orientation on terrapin behaviour around crab pots and overall terrapin capture rates. In a controlled laboratory setting, terrapins investigated crab pots more frequently when crab pots were baited with fish versus chicken. Terrapins were captured more frequently when BRDs were not installed. The presence of the BRDs also increased the length of time necessary for a terrapin to enter a crab pot and decreased the proportion of entries relative to the number of investigations. Vertically‐oriented BRDs were more effective than horizontally‐oriented BRDs at reducing terrapin captures. To prevent the continued decline of terrapin populations due to crab fisheries, it is recommended that crabbers avoid the use of fish as bait in crab pots to reduce the attractiveness of pots to terrapins and fit all crab pots with vertically‐oriented BRDs to reduce terrapin entrapment. Copyright © 2015 John Wiley & Sons, Ltd.

Individual size is an important determinant of the outcomes of inter- and intraspecific interactions. Different-sized members of a guild might represent prey, competitors, or predators. Although direct predation rates might be low, trait-mediated indirect effects of predators on prey can yield altered activity, microhabitat use, survival, and growth. If individuals respond to all sizes of a predator regardless of the predation threat, antipredator behaviors might incur costs for prey as they forgo foraging opportunities or experience predation by other predators. Accurate assessment of predation risk would minimize costs resulting from antipredator behavior. We evaluated the ability of larval salamanders to assess predation risk and alter their habitat selection in response to intraguild competitors and predators. Specifically, we assessed behavioral responses to the presence of a conspecific, a similarly sized heterospecific, and a small or large individual of a predatory species. We predicted that larval salamanders would select habitat differently in the presence of a large predatory heterospecific, but not in the presence of similarly sized heterospecifics or conspecifics. The focal species occupied habitat 29 ± 0.02% farther from a large heterospecific predator than from small heterospecifics, even if the heterospecifics were smaller individuals of the predatory species. The focal species also exhibited escape behaviors only in the presence of the large members of the predatory species. These data indicate that salamander larvae can assess size-specific predation threats, minimizing predation risk through use of antipredator behaviors.

Although usually not as obvious as pollution, deforestation, or urban sprawl, the introduction of in…