Burrowing, herbivorous mammals play important roles as ecosystem engineers and keystone species of grassland ecosystems around the world, but populations of many species have declined dramatically because of myriad threats from human activities. Prairie dogs (Cynomys spp.) play important roles in shaping the central grasslands of North America, and have declined by about 98% across their range, with consequent losses in associated species and grassland habitat. This has prompted much interest in restoring their populations to protected areas. Managers lack a clear understanding of the long‐term success of reintroductions, however, and how success may vary across different species of prairie dogs and their widespread geographic ranges. We reintroduced over 1,000 Gunnison's prairie dogs (C. gunnisoni) to a semi‐arid grassland ecosystem in the southern portion of their range in central New Mexico, USA, and used standard capture–recapture methods to study their population dynamics over a period of 8 years. Mean adult survival was 27% over the course of the study, with precipitation identified as the primary driver of survival. Estimated survival was below 12% during severe drought periods and during the first few years following initial reintroduction, the latter likely because of high predation. Consequently, multiple releases of animals were required to prevent extirpation, and the long‐term sustainability of this population remains questionable. Over the 8 years of our study, our site experienced 4 severe droughts during spring, the key period for prairie dog mating, pregnancy, and lactation. Production of offspring at the site was low, likely because of the dry and variable conditions that occurred. We show that prairie dog restoration in semi‐arid grassland environments that are typical of the lower elevations and southern extent of their range may not succeed in producing viable colonies, and that dedicated management for multiple years is needed to counteract periods of slow or negative population growth. Our findings underscore the importance of maintaining and expanding existing colonies wherever possible in these more arid regions, and suggest that reintroductions should be treated as a secondary management strategy. Our work also reveals the high vulnerability of prairie dog population extinction due to drought, which has important implications for Gunnison's prairie dog conservation under a warming and drying climate. © 2014 The Wildlife Society.

A B S T R A C TThe fishery of the mangrove crab (Ucides cordatus) is one of the oldest sources of food, income and extractive activity in the estuarine systems of Brazil. The state of São Paulo has the largest population of any Brazilian state, and the city of Cananéia, in the Brazilian southeast has the highest recorded level of exploitation of the uçá-crab. Since 1990, this species has been under intense exploitation pressure due to the unauthorized use of a type of trap called 'redinha'. This type of fishing gear is considered harmful and is prohibited by Brazilian law, although its use is very common throughout the country. This study aims to evaluate the exploitation patterns of U. cordatus based on landing data and monitoring of the crab fishermen to verify the population structure of the crab stock and to identify the factors that influence the catches. A general view of the sustainability of the fishery for this resource is also provided for five defined mangrove sectors (areas A to E) at Cananéia. For this purpose, fishery data were recorded during 2009-2010 by the Instituto de Pesca (APTA/SAA-SP), and monitoring of the capture procedures used by two fishermen was conducted to obtain biometry data (CW, carapace width) and gender data for the captured crabs. The redinha trap was very efficient (86.4%) and produced sustainable catches because the trapped crabs were legalsized males (CW>60 mm), although some traps are lost or remain in the mangrove swamps and can cause pollution by introducing plastic debris. The fishery data were evaluated with a General Linear Model (GLM) based on six factors: the characteristics of the crab fishermen, the time of capture (by month and year), the lunar phase, the productive sector and the reproductive period. The individual crab fishermen's empirical knowledge, the year of capture and the productive sector were the strongest influences on the crab catch per unit effort (CPUE). Differing extraction patterns were found in the five sectors examined in the Cananéia estuary. These findings underscore the need for a reassessment of the prohibition of the trap's use, raising discussion as to its possible construction with biodegradable materials, thus ensuring profitable and sustainable catches through a local participatory management process. R E S U M OA pesca do caranguejo-uçá (Ucides cordatus) é uma das mais antigas atividades extrativas para a obtenção de fonte de alimento e renda nos sistemas estuarinos do Brasil. O Estado de São Paulo é o mais populoso e a cidade de Cananéia, localizada no sudeste, tem o maior volume registrado de captura do caranguejo-uçá para a região. Desde 1990, esta espécie vem sofrendo intensa pressão pesqueira pelo uso indiscriminado de um tipo de armadilha conhecida como "redinha". Este tipo de arte de pesca é considerado uma ameaça à população do caranguejo, sendo proibido pela legislação brasileira, embora seu uso seja comum em todo o país. Este estudo teve como objetivo avaliar os padrões de exploração de U. cordatus com base em dados de desem...