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Abstract: Complete population estimates for widely distributed species are rarely possible. However, for the third time in 10 years, an International Piping Plover (Charadrius melodus) Breeding and Winter Census was conducted throughout the species range in 2001. Nearly 1,400 participants from 32 U.S. states and Puerto Rico; 9 Canadian provinces; St. Pierre and Miquelon, France; Cuba; and the Bahamas visited 2,244 sites covering 11,836 km of shoreline habitat. During the winter census, 2,389 piping plovers were observed at 33.5% of potentially occupied sites (n = 352). Of these, 56.8% had ≤10 birds present. The breeding census recorded 5,945 adults at 777 of 1,892 sites surveyed. More than 80% of sites with piping plovers present had ≤10 birds. Results indicated an 8.4% increase from 1991 but only a 0.2% increase since 1996. Regional trends suggest that since 1991, number of breeding birds increased on the Atlantic Coast by 78% (2,920 birds; 12.4% increase since 1996) and by 80% in the Great Lakes (72 birds; 50% increase since 1996). However, plovers declined 15% (2,953 birds; 10% decline since 1996) in Prairie Canada/U.S. northern Great Plains. Subregional trends since 1991 reflect a 32.4% decline in Prairie Canada (972 birds; 42.4% decline since 1996), a 2.5% decline in the U.S. northern Great Plains (1,981 birds; 24% increase since 1996), 5.5% decline in eastern Canada (481 birds; 14% increase since 1996), although a 66.2% increase on the U.S. Atlantic Coast (2,430 birds; 12% since 1996). While numbers were down in much of the U.S. northern Great Plains since 1996, an increase (460%, 1,048 birds; 67.7% increase since 1991) was detected on the Missouri River. Results from 3 complete species census efforts provide essential data for conservation planning and assessment and illustrate the utility of global censuses for species of concern.  相似文献   

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Loss of breeding habitat and nest predation have contributed to the decline of many shorebird species. The United States Army Corps of Engineers (USACE) initiated a piping plover (Charadrius melodus) habitat creation and augmentation program on the Missouri River in the summer of 2004. The USACE increased unvegetated sandbar habitat by depositing dredged material (engineered sandbars) and by clearing vegetation from existing sandbars (managed sandbars). We evaluated the effects of this increase in nesting and foraging habitat on habitat selection and nest daily survival rate (DSR) of piping plovers on Lewis and Clark Lake and the Gavins Point Reach of the Missouri River from 2005 to 2007 (n = 623 nests). Piping plovers selected engineered sandbars more often than expected based on area and selected natural and managed habitats less than expected based on area. Daily survival rate on engineered sandbars was significantly higher than on natural or managed sandbars (log odds: 2.50, 95% CI: 1.05–5.94). Thus, plovers' habitat selection may have increased their nesting success. Our results suggest that habitat augmentation may stave off declines in piping plover populations limited by insufficient habitat and low nesting success. © 2011 The Wildlife Society.  相似文献   

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Resightings of uniquely marked birds from 2001 to 2008 were used to determine winter distributions of 4 breeding populations of a species at risk, the piping plover (Charadrius melodus). Although considerable overlap exists, a distinct pattern in winter distributions was evident. Birds originating from eastern Canada wintered farthest north compared to other populations. Most individuals from the United States Great Lakes were found in South Carolina and Georgia in winter, whereas birds from eastern Canada were found primarily in North Carolina. Although the great majority of birds marked in Prairie Canada were observed wintering in Texas, particularly southern Texas, breeding plovers from the United States Great Plains were more widely distributed on the gulf coast from Florida to Texas. Very few large-scale movements of individuals in winter were reported either within or between years. This study highlights the significance of geographic regions for eastern Canada, the United States Great Lakes, the United States Great Plains, and Prairie Canada populations, and demonstrates relatively high winter site fidelity. This information will help focus conservation efforts for specific breeding populations during the winter. © 2011 The Wildlife Society.  相似文献   

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ABSTRACT We calculated expenditures and hours of staff and volunteer time dedicated to monitoring and managing the United States breeding population of Atlantic Coast piping plovers (Charadrius melodus) in 1993 and 2002 and considered implications for recovery of this management-dependent species. In 2002, 73 federal, state, and local governmental agencies and private organizations played key roles in conservation efforts at 281 piping plover breeding sites. Total inflation-adjusted estimated expenditures increased by 51% between 1993 and 2002, from US$2.28 million to $3.44 million, but annual per-pair expenditures declined 4% from $2,459 to $2,350, and hours of paid-staff effort were similar (93 hr/pair in 1993, 95 hr in 2002). Expenditures for on-site monitoring and management were greater than for 6 other categories of expenses in both years and increased from 42% to 59% of total costs between 1993 and 2002. Staff time and expenditures were higher at sites where more labor-intensive efforts to protect plovers from recreation and other human use were necessitated by greater human accessibility. Total expenditures in 2002 were modest compared to those for some other threatened and endangered species and to costs of large beach-stabilization projects. Our results provide a baseline for estimating future costs of piping plover protection, including development and implementation of the long-term management agreements that will be required to remove this species from United States Endangered Species Act protection. Impediments to reducing costs for Atlantic Coast piping plovers are the species’ widespread distribution at low densities and the unrelenting threats posed by human activities and predators. Modest economies of scale may be achieved through arrangements for management and monitoring that span multiple landowners and include other at-risk beach species.  相似文献   

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ABSTRACT.   The threatened Atlantic Coast population of Piping Plovers ( Charadrius melodus ) has not increased in recent years and remains 332 pairs short of the recovery goal of 2000 pairs. Habitat loss to development is a major threat to the population, and there has been interest in restoring nesting and foraging habitat. However, the demographic response of coastal Piping Plovers to either habitat loss or creation has not been documented. We estimated survival rates and site fidelity of a declining Piping Plover population on Long Island, New York, from 2001 to 2005 on a beach subject to human development and recreation. The mean annual adult survival was 0.703 ± 0.032 (SE) and was similar among years. Site fidelity during the period of territory establishment averaged 0.827 ± 0.069 (SE). Given this high site fidelity, ensuring the survival of adults is important for maintaining local populations. Although the 2002–2004 average was high, site fidelity was apparently lower in 2003 than in 2002. This decrease in site fidelity may have been related to several years of habitat loss and increasing predation of nests or chicks, as reported in a partly concurrent long-term study at our site. The species-level effect of local dispersal due to anthropogenic habitat loss depends on the fitness of dispersers, and is currently unknown for Piping Plovers.  相似文献   

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Mobility of precocial chicks facilitates self-feeding and escape from predators, but also allows chicks to move into potentially dangerous areas. At Cape Hatteras National Seashore and Pea Island National Wildlife Refuge, North Carolina, precocial Piping Plovers (Charadrius melodus) are managed with vehicle and pedestrian exclusion buffers to reduce potential anthropogenic disturbance and mortality. From 2015 to 2018, we monitored 23 broods from hatching until fledging age (25 days), and recorded brood locations, chick behavior, and potentially disruptive predators, people, or vehicles. We estimated straight-line hourly movement rates relative to brood habitat selection, behavior, and potential disturbance stimuli, daily movement distances, and 95% minimum convex polygon home range areas of broods through the pre-fledging period. Daily brood movements , range = 0–327.3 m/d) varied by age and year. Hourly movements also varied , range = 0.04–1450.9 m/h), but were not well described by the factors we tested. Daily and hourly movements were generally shorter than current management buffer sizes, broods were always observed within protective buffers, and were rarely disturbed by human activity or possible predators. Home range sizes of broods ( increased as broods aged. Our results show that movements by plover broods can be variable and relatively unpredictable across temporal and spatial scales, but the low rate of brood disturbance suggests effective management of anthropogenic disturbance. We recommend that under current conditions, regular monitoring by managers should continue to ensure that the size and location of implemented buffers track actual brood use without exposing broods to risks from human beach users.  相似文献   

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Abstract: Recent technological innovations allow remote monitoring of avian nest temperature that minimizes disturbance and expense without altering clutch sizes. However, the efficacy of such techniques has not been determined for ground-nesting birds. We compared the efficacy of 2 techniques, iButton® data loggers (Maxim/Dallas Semiconductor Corp., Sunnyvale, CA) and custom-built thermocouples, to measure nest temperature of piping plovers (Charadrius melodus) relative to nest attendance at Cape Cod National Seashore, Massachusetts, USA. Neither technique affected hatching success (U = 389.5, P = 0.874) or rates of predation of nests containing devices (P = 0.894). We estimated nest attendance successfully with thermocouples in nests as long as air and surface temperatures were <29° Cand 43° C, respectively. Although iButtons could not be used to determine duration of on-bouts and off-bouts of incubating piping plovers, they were effective at determining when nests were abandoned or predated. We recommend the use of thermocouples for studying nest attendance of ground-nesting birds, in general, and of threatened and endangered species, in particular, where disturbance should be minimized and altering clutch sizes is not feasible.  相似文献   

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Abstract: We tested the hypothesis that piping plover (Charadrius melodus) habitat quality and chick survival on the Missouri River, USA, were lower on a cold-water reservoir and downstream from a hypolimnetic (cold-water) release dam with diel water fluctuations (Garrison Dam) than downstream from an epilimnetic dam (Gavins Point Dam). Plovers in adjacent alkali wetlands provided an index to the maximum reproductive potential in the region. Chicks gained weight more rapidly in the alkali wetlands than on epilimnetic and hypolimnetic river reaches. Invertebrate numbers and biomass were higher in the wetlands and epilimnetic reach, but chick survival was lower on the epilimnetic reach. Thus, piping plovers adapted to a variety of prey densities, and other factors, likely predation, reduced survival rates in the epilimnetic reach. Temporal and spatial variability in site quality indices suggests the need for a regional management strategy with different strategies at each site. Managers can minimize effects of local fluctuations in resource abundance and predators by ensuring protection of or creating geographically dispersed habitat. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):682–687; 2008)  相似文献   

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Evaluating the possible effects of intensive research on species being studied and on the results of studies is important for both ethical and scientific reasons. We captured, banded, recaptured, and measured prefledged Piping Plover (Charadrius melodus) chicks during the 2010 breeding season at Lewis and Clark Lake on the Missouri River in South Dakota. We evaluated the potential for increased mortality related to frequent handling of chicks with an experiment that compared the survival of chicks handled a single time for banding (N = 48) to chicks handled repeatedly from hatch to fledge (N = 50). Estimates of daily survival rate (?) for chicks in the two treatments did not differ (?single‐capture = 0.984 ± 0.006, ?multiple‐capture = 0.985 ± 0.006). Similar to previous studies, we found little evidence of increased prefledge mortality associated with frequent handling of Piping Plover chicks. However, because the effects of frequent handling of shorebird chicks may vary among species and other factors such as habitat quality (e.g., food availability), we suggest that, where possible, researchers include experiments similar to ours to evaluate possible research impacts, especially when studying threatened and endangered species.  相似文献   

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ABSTRACT An accurate understanding of factors influencing survival and how they affect population growth are required to determine the best conservation strategies for small populations, especially near the limit of a species' range. We estimated adult and juvenile survival for a small population of the threatened western snowy plover (Charadrius alexandrinus nivosus) in coastal northern California over 7 years (2001–2007). We also evaluated population structure and growth to determine the relative importance of immigration and local recruitment. Apparent survival for adult males (φ = 0.61 ± 0.08) was greater than that of adult females (φ = 0.50 ± 0.11), and survival of adults was greater than for juveniles (φ = 0.40 ± 0.06). An algebraic assessment of population growth (Λ) revealed that fecundity and survival were insufficient to maintain the population (Λ = 0.66–0.77), whereas estimates based on consecutive annual counts (Λ = 0.96 ± 0.26) and a Pradel model (Λ = 0.92 ± 0.11) suggested the population was more stable. These results, combined with annual variation in the number of newly marked plovers, indicate that the local population was maintained by immigration and can be classified as a sink. Management actions aimed at increasing fecundity, including predator control and greater restrictions on human activity, may be necessary to maintain this population; actions aimed at increasing adult survival are more challenging.  相似文献   

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Low hatching success may limit progress towards reaching productivity goals for Atlantic Coast piping plover (Charadrius melodus) recovery, despite management strategies to protect eggs from predators and decrease human disturbance of birds on nests. We measured piping plover hatching success on Eastern Long Island beaches and identified the major causes of egg failure to better understand why eggs that were otherwise intact (not depredated or destroyed by tidal flooding) failed to hatch. We documented egg and nest fates, dissected contents of unhatched eggs to determine viability, and recorded human and predator activity near a subset of plover nests on Suffolk County Parks properties. The low hatching success we recorded (0.60) in 2006 and 2007 would require higher chick survival rates than are typically observed for piping plovers to meet recovery targets for productivity. Few eggs showed signs of poor viability and overall egg hatchability was comparable to other ground nesting birds. Most egg failure was due to either depredation at unexclosed nests or nest abandonment by adults. The best predictor of nest abandonment was the maximum number of red fox tracks (Vulpes vulpes) counted on nearby transects (β = −1.16, 95% CI: −2.0 to −0.3) and we found evidence that plovers abandoned eggs in response to predation risk (e.g., a fox circling a nest exclosure). Adults from abandoned nests may have deserted eggs or been depredated. In either case, intact and viable eggs were abandoned. Nest abandonment was not related to human activity near nests, which were buffered from human disturbance by symbolic string fencing. Our results suggest that depredation and nest abandonment (e.g., desertion or death of adults) due to predator disturbance, not human disturbance or poor egg viability, contributed to the low hatching success we recorded. Active predator removal in addition to modification of predator exclosure use and design may be necessary to prevent direct (egg depredation) and indirect (nest abandonment) negative effects of predators on hatching success. © 2010 The Wildlife Society.  相似文献   

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River flow management and modification is a global issue, and its effects on river-dependent organisms are pervasive. Flow modification can directly affect avian species through mortality or habitat loss, but less is known about indirect and sublethal effects of flow modification on reproductive output in these species. Young birds are more vulnerable to predation between hatching and fledging than after flight is achieved, but tradeoffs must be made to balance growth and survival. Predation pressure appears to be a significant factor affecting the time to fledging in altricial birds, but less is known about this threat for precocial birds. Birds reaching fledging earlier should have greater rates of survival to migration because their predator escape repertoire includes flight at an earlier age. We evaluated the effect of varying outflows from the Gavins Point Dam on the growth, age at fledging, and survival of piping plover (Charadrius melodus) chicks on the Missouri River (2006–2009). The study was characterized by 2 relatively high flow years (2006 and 2009) and 2 relatively low flow years (2007 and 2008). We used success rate in recapturing chicks in capture–mark–recapture models as an index for fledging. We attempted to recapture all chicks (n = 1,099) by hand every 3–4 days throughout the season to acquire morphological measurements. Models indicated that as flows from the dam increased, age at fledging increased. We also found that increasing flows were associated with decreasing daily survival rates (βflow = −2.401, 95% CI: −4.351 to −0.452). Flow was also negatively related to chick mass gain, but we found less evidence for an effect on wing-chord length. Increased flows covered wet-substrate foraging habitat, and likely affected plover reproductive output directly through chick survival and indirectly through decreased growth and increased fledging times. © The Wildlife Society, 2013  相似文献   

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Predation of nests and young is one of the limiting factors in the conservation of birds; understanding environmental covariates of predator distribution can assist with decisions regarding the best management strategies to reduce predation risk. The habitat of beach-nesting birds is often reshaped by storms in ways that may affect nest predation, such as by flattening vegetated dunes where mammals hunt, but human management of beaches tries to prevent the effects of storms on the landscape with unknown implications for predator distributions. Moreover, human development may affect predator distributions by subsidizing food and shelter. To determine the relationship between predator occupancy and landscape features in beach-nesting bird habitat, we repeated mammalian predator track surveys 8 times/year at 90 plots in southern New Jersey, USA, from 2015–2017. We used dynamic occupancy models to estimate the probability of use by red foxes (Vulpes vulpes) and to document changes in habitat use as related to landcover types over the avian breeding season within years. We had 373 red fox detections with years pooled. Detection probability for red foxes varied by year, and probability of use decreased as the distance to the nearest primary dune increased. We found no evidence that red fox habitat use depended on distance to human development. Our results suggest that conserving nesting habitat that includes open areas (i.e., storm overwash [whereby vegetation is scoured by tidal flooding]) may reduce predation risk because beach-nesting birds would not be forced into nesting close to dunes, which are typically used for hunting by red foxes. © 2020 The Wildlife Society.  相似文献   

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Habitat restoration projects are often deemed successful based on the presence of the target species within the habitat; however, in some cases the restored habitat acts as an ecological trap and does not help to improve the reproductive success of the target species. Understanding wildlife–habitat relationships through precise measurements of animal behavior can identify critical resources that contribute to high quality habitat and improve habitat restoration practice. We evaluated the success of a restored piping plover (Charadrius melodus) breeding habitat in New Jersey, USA. We identified the major factors influencing foraging rates, compared foraging activity budgets over 3 yr at restored and natural habitats, and explored the potential of artificial tidal ponds as a viable restoration alternative. Adult foraging rates were higher in artificial pond and ephemeral pool habitats, during low tide, and after breeding activity ended. Adult foraging rates were impeded by the presence of people and vehicles within 50 m. Chick foraging rates were highest at artificial ponds and bay shores and lowest in dunes and on sand flats. Chick foraging rates were strongly hindered by the presence of corvids and the number of people within 50 m. In addition, at artificial tidal ponds, piping plovers spent more time foraging and less time engaged in defensive behaviors (vigilance, crouching, and fleeing) compared to other potential habitats. Our findings support the hypothesis that artificial tidal ponds are a valuable, perhaps superior, foraging habitat. Future beach restoration projects should include this feature to maximize habitat quality and restoration success. © 2011 The Wildlife Society.  相似文献   

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ABSTRACT To conserve threatened species, managers require predictions about the effects of natural and anthropogenic factors on population growth that in turn require accurate estimates of survival, birth, and dispersal rates, and their correlation with natural and anthropogenic factors. For Piping Plovers (Charadrius melodus), fledging rate is often more amenable to management than adult survival, and population models can be used to estimate the productivity (young produced per breeding female) necessary to maintain or increase populations for given levels of survival. We estimated true survival and site fidelity of adult and subadult (from fledging to second year) Piping Plovers breeding in Saskatchewan using mark‐resight data from 2002 to 2009. By estimating true survival rather than apparent survival (which is confounded with permanent emigration), we were able to provide more accurate projections of population trends. Average adult and subadult survival rates during our study were 0.80 and 0.57, respectively. Adult survival declined over time, possibly due in part to the loss of one breeding site to flooding. Average adult and subadult site fidelity were 0.86 and 0.46, respectively. Adult site fidelity declined during our study at two study sites, most strongly at the flooded site. Male and female Piping Plovers had similar survival rates, but males had greater site fidelity than females in some years. Based on our survival estimates, productivity needed for a stationary population was 0.75, a benchmark used for plover management on the Atlantic Coast, but not previously estimated for Prairie Canada. In stochastic simulations incorporating literature‐based variation in survival rates, productivity needed for a stationary population increased to 0.86, still lower than that previously estimated for western populations. Mean productivity for our study sites ranged from 0.87 to 0.96 fledged young per pair. Our results suggest that fledging rates of Piping Plovers in Saskatchewan were sufficient to ensure a stationary or increasing population during our study period. However, large‐scale habitat changes such as drought or anthropogenic flooding may lead to dispersal of breeding adults and possibly mortality that will increase the fledging rate needed for a stationary population.  相似文献   

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Techniques for captive-rearing and releasing piping plovers (Charadrius melodus) were developed using a surrogate species, killdeer (Charadrius vociferus). We compared captive- and parent-reared killdeer, and parent-reared piping plovers and determined that growth and behavior were similar. After surrogate trials determined that captive-rearing was feasible, we used the same methods to raise piping plover chicks from salvaged eggs. For captive-reared chick of both species, survival to fledging was higher than and behaviors similar to parent-reared chicks in the wild. Rearing techniques were fine-tuned, and ten piping plover fledglings were released to the wild. Based on our results, we developed recommendations for captive-rearing piping plovers using salvaged eggs to enhance productivity of small populations. Zoo Biol 16:461–477, 1997. © 1997 Wiley-Liss, Inc.  相似文献   

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