Suchergebnisse

AbstractProactive Conservation is a paradigm of natural resource management in the United States that encourages voluntary, collaborative efforts to restore species before they need to be protected through government regulations. This paradigm is widely used to conserve at-risk species today, and when used in conjunction with the Policy for Evaluation of Conservation Efforts (PECE), it allows for successful conservation actions to preclude listing of species under the Endangered Species Act (ESA). Despite the popularity of this paradigm, and recent flagship examples of its use (e.g., greater sage grouse, Centrocercus urophasianus), critical assessments of the outcomes of Proactive Conservation are lacking from the standpoint of species status and recovery metrics. Here, we provide such an evaluation, using the New England cottontail (Sylvilagus transitionalis), heralded as a success of Proactive Conservation efforts in the northeastern United States, as a case study. We review the history and current status of the species, based on the state of the science, in the context of the Conservation Initiative, and the 2015 PECE decision not to the list the species under the ESA. In addition to the impacts of the PECE decision on the New England cottontail conservation specifically, our review also evaluates the benefits and limits of the Proactive Conservation paradigm more broadly, and we make recommendations for its role in relation to ESA implementation for the future of at-risk species management. We find that the status and assurances for recovery under the PECE policy, presented at the time of the New England cottontail listing decision, were overly optimistic, and the status of the species has worsened in subsequent years. We suggest that use of PECE to avoid listing may occur because of the perception of the ESA as a punitive law and a misconception that it is a failure, although very few listed species have gone extinct. Redefining recovery to decouple it from delisting and instead link it to probability of persistence under recommended conservation measures would remove some of the stigma of listing, and it would strengthen the role of Species Status Assessments in endangered species conservation.

Buffer zones, calculated by flight-initiation distance (FID), are often used to reduce anthropogenic disturbances to wildlife, but FID can vary significantly across life-history stages. We examined the behavioral effect of potential natural (gulls and shorebirds) and anthropogenic (pedestrians) disturbance sources to staging roseate (Sterna dougallii) and common tern (S. hirundo) flocks from July to September in 2014 and 2015 at Cape Cod, Massachusetts, USA. We estimated the proportion of the flock exhibiting different responses to potential disturbance sources as a function of distance, flock size, percent roseate terns, and local disturbance rates, using Bayesian zero-and-one inflated beta regression. The proportion of tern flocks responding to the presence of shorebirds by flying was low (0.01 +/- 0.001 [SE]) and did not vary by distance or other covariates, whereas the proportion flying in response to gulls increased as distance decreased, with smaller flocks, and with flocks with a larger proportion of roseate terns being more sensitive to gull presence. Prolonged flight response rapidly increased in probability from 0.0 to as much as 1.0 as distance from pedestrians to the flock decreased from 100 m and was much more likely with smaller flocks. Pedestrian activity levels also had an effect on flock responses; those engaged in active behaviors such as jogging were more likely to cause flushing than those engaged in passive behaviors. Terns seemed to view pedestrians as more of a threat than shorebirds and gulls, even though gulls are frequent kleptoparasites of terns. Pedestrians >120 m from a tern flock generally elicited the same probability of flight response as shorebirds and gulls. We recommend managers maintain anthropogenic disturbance levels at or below the intensity of those from natural sources at sites where recreation and wildlife values are both important. Because staging tern flocks may use a variety of areas within a site, we recommend instituting a 100-m buffer around areas potentially used by staging flocks at Cape Cod, where we studied every location roseate terns are known to use in large numbers. For other sites used by mixed-species tern flocks, we recommend the use of our field and analytical methods to develop appropriate buffer distances that will keep pedestrians far enough away to reduce the likelihood of flight and other non-locomotive anti-predator behaviors. These buffer zones will also benefit other species sensitive to human activity. (c) 2018 The Wildlife Society. ; Cape Cod National Seashore; United States Geological SurveyUnited States Geological Survey; CNY Wildfowlers Association; Edna Baily Sussman Foundation ; The use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the United States Government. The USFWS provided necessary resources to complete the study. M. E. Hake, R. P. Cook, J. J. Taylor, and K. E. Iaquinto provided logistical support and site access. J. L. Correia, J. C. May, S. S. Brady, and P. L. Gallo assisted with data collection. The Cape Cod National Seashore, United States Geological Survey, CNY Wildfowlers Association, and Edna Baily Sussman Foundation provided funding. ; Public domain authored by a U.S. government employee

When individuals breed more than once, parents are faced with the choice of whether to re-mate with their old partner or divorce and select a new mate. Evolutionary theory predicts that, following successful reproduction with a given partner, that partner should be retained for future reproduction. However, recent work in a polygamous bird, has instead indicated that successful parents divorced more often than failed breeders (Halimubieke et al. in Ecol Evol 9:10734-10745, 2019), because one parent can benefit by mating with a new partner and reproducing shortly after divorce. Here we investigate whether successful breeding predicts divorce using data from 14 well-monitored populations of plovers (Charadrius spp.). We show that successful nesting leads to divorce, whereas nest failure leads to retention of the mate for follow-up breeding. Plovers that divorced their partners and simultaneously deserted their broods produced more offspring within a season than parents that retained their mate. Our work provides a counterpoint to theoretical expectations that divorce is triggered by low reproductive success, and supports adaptive explanations of divorce as a strategy to improve individual reproductive success. In addition, we show that temperature may modulate these costs and benefits, and contribute to dynamic variation in patterns of divorce across plover breeding systems. ; Chinese Scholarship CouncilChina Scholarship Council; Royal Society Wolfson Merit AwardRoyal Society of London [WM170050]; APEX [APX\R1\191045]; Leverhulme TrustLeverhulme Trust [RF/2/RFG/2005/0279, ID200660763]; National Research, Development and Innovation Office of Hungary [ELVONAL KKP-126949, K-116310, NN 125642]; [NBAF547]; [NBAF933]; [NBAF441] ; This work was supported by the Chinese Scholarship Council (to NH). Royal Society Wolfson Merit Award WM170050, APEX APX\R1\191045 and Leverhulme Trust (RF/2/RFG/2005/0279, ID200660763) (to TS). the National Research, Development and Innovation Office of Hungary (ELVONAL KKP-126949, K-116310 (to TS, JOV, VK and NH); NN 125642 (to AK and GCM)). NBAF-Sheffield supported by grants (NBAF547, NBAF933, NBAF441). Other funding sources of fieldworks are provided in the Supplementary acknowledgements. We thank all fieldwork volunteers and people who have helped with data collection. Thanks to Andras Liker, Philippa Harding, Zitan Song, Claire Tanner and Kees Wanders for their advice on previous versions of the manuscript. We also thank Siyu Ding for providing original plover illustrations and the map in Fig. 1. ; Public domain authored by a U.S. government employee