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Jones Gavin M. Kramer H. Anu Whitmore Sheila A. Berigan William J. Tempel Douglas J. Wood Connor M. Hobart Brendan K. Erker Tedward Atuo Fidelis A. Pietrunti Nicole F. Kelsey Rodd Gutiérrez R. J. Peery M. Zachariah 《Landscape Ecology》2020,35(5):1199-1213
Context
Climate and land-use change have led to disturbance regimes in many ecosystems without a historical analog, leading to uncertainty about how species adapted to past conditions will respond to novel post-disturbance landscapes.
ObjectivesWe examined habitat selection by spotted owls in a post-fire landscape. We tested whether selection or avoidance of severely burned areas could be explained by patch size or configuration, and whether variation in selection among individuals could be explained by differences in habitat availability.
MethodsWe applied mixed-effects models to GPS data from 20 spotted owls in the Sierra Nevada, California, USA, with individual owls occupying home ranges spanning a broad range of post-fire conditions after the 2014 King Fire.
ResultsIndividual spotted owls whose home ranges experienced less severe fire (<?5% of home range severely burned) tended to select severely burned forest, but owls avoided severely burned forest when more of their home range was affected (~ 5–40%). Owls also tended to select severe fire patches that were smaller in size and more complex in shape, and rarely traveled?>?100-m into severe fire patches. Spotted owls avoided areas that had experienced post-fire salvage logging but the interpretation of this effect was nuanced. Owls also avoided areas that were classified as open and/or young forest prior to the fire.
ConclusionsOur results support the hypothesis that spotted owls are adapted to historical fire regimes characterized by small severe fire patches in this region. Shifts in disturbance regimes that produce novel landscape patterns characterized by large, homogeneous patches of high-severity fire may negatively affect this species.
相似文献2.
Abstract Conservation efforts for endangered Snake River sockeye salmon ( Oncorhynchus nerka ) have been hindered by high en route adult mortality during their ∼1450 km freshwater spawning migration. Identifying causal factors for this mortality has been difficult given very small (often <10 fish) annual returns in recent decades. However, several hundred hatchery-bred fish returned in 2000 and we intercepted and radio-tagged 31 in mid-migration to monitor behaviours and survival. All fish initially migrated at similar rates, but later-timed fish eventually slowed migration and were far more likely to be unsuccessful. Late-season mortality was strongly associated with water temperatures near tolerance thresholds (21–24 °C). The data also suggest increased risk for fish in poor initial condition (i.e., with injuries or parasites) and probable recent selection against late-timed salmon. Results parallel temperature- and condition-related adult mortality in Columbia and Fraser River sockeye salmon populations and demonstrate the potential vulnerability of marginal southern populations to regional climate warming. 相似文献
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Landscape Ecology - Climate change will cause species extinctions that will be exacerbated by human-caused landscape changes, preventing species from tracking shifting climatic niches. Although... 相似文献
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Erez Hanael Shelly Baruch Orit Chai Liron Lishitsky Tal Blum Kira Rapoport Marco Ruggeri Zahi Aizenberg Dana Peery Nina Meyerhoff Holger Andreas Volk Steven De Decker Andrea Tipold Wolfgang Baumgaertner Alon Friedman Merav Shamir 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2023,37(2):606-617
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Congenital oesophageal stricture was diagnosed via endoscopy in a 3‐day‐old Arabian filly suffering from nasal milk regurgitation. Vascular ring anomaly or other extramural, intramural or intraluminal causes were not identified on radiographs or on a computed tomography scan; thus a functional abnormality was suspected. The filly was treated with antibiotics for aspiration pneumonia and was fed milk through an indwelling nasoesophageal tube. Two sessions of balloon bougienage at the stenotic site, under sedation, resulted in marked clinical improvement and thereafter the filly was gradually reintroduced to suckling from the mare. The filly was discharged from the hospital after 17 days and on follow‐up there were no reports of food regurgitation even after the introduction of solid food. The filly was still doing well in the latest follow‐up at age 11 months. 相似文献
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The expansion of human activities into rural areas and natural landscapes has resulted in widespread increases in the abundance of synanthropic species that threaten rarer native species. Quantitative assessments of how much impacts need to be reduced to reach acceptable levels of risk to the affected species are rarely conducted prior to the implementation of control measures, and it is perhaps not surprising that many efforts have not yielded the desired outcome. Here, we used matrix-based population viability analysis models to show that reducing predation by rapidly growing corvid populations on marbled murrelet (Brachyramphus marmoratus) nests likely constitutes an effective means for recovering a declining murrelet population in central California. For example, a modest 40% reduction in predation reduced extinction risk dramatically from 95.8% to 4.6% over 100 years and a 60% reduction resulted in a stable population (λ = 1) when the proportion of breeders, renesting rates, and corvid predation rates were assumed to be 0.77, 0.13, and 0.69, respectively. However, nest predation would only need to be reduced by 40% to produce a stable population if corvid management was coupled with a modest increase in after-hatch-year survival from 0.896 to 0.910. Corvid control resulted in greater gains in murrelet population size when the maximum number of breeders was allowed to increase over the projection period, as might be expected if the amount of old-growth nesting habitat increased over time, but extinction risk was insensitive to the presence of a carrying capacity. Approximately half of known murrelet nests in central California are within 1 km of heavily used campgrounds in a single state park, indicating that significant gains in viability could be achieved by targeting efforts in small areas providing corvid food subsidies. Risk assessments such as ours can provide quantitative prioritization rationale for efforts intended to mitigate the impacts of synanthropic species on threatened species. 相似文献
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OBJECTIVE: To describe a surgical technique for radical mastectomy in ruminants and to report experience and outcome in 20 animals. STUDY DESIGN: Retrospective study. ANIMALS: Seventeen goats and 3 cows. METHODS: Medical records of ruminants that had radical mastectomy between June 1, 1987 and June 1, 2003 were reviewed. Follow-up information was obtained by telephone interview of owners. RESULTS: One animal died within 24 hours from complications of gangrenous mastitis and another died from necrotizing cellulitis. Eighteen animals were discharged and follow-up information was available for 15 animals; 12 animals lived at least 1 year postoperatively. CONCLUSIONS: Ruminants with severe but localized diseases of the udder did well after radical mastectomy. The procedure was well tolerated, made the animals more comfortable, and potentially prolonged their lives as pets. CLINICAL RELEVANCE: Radical mastectomy can be a safe and effective procedure for ruminants with udder disease, with few complications. 相似文献
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Matthew L. Keefer Charles T. Boggs Christopher A. Peery Christopher C. Caudill 《Ecology of Freshwater Fish》2013,22(1):1-10
Low dam passage rates of adult Pacific lamprey (Entosphenus tridentatus) during upstream spawning migration have been implicated in the species' steep decline in the interior Columbia River basin. In this 2000–2010 study, we used radiotelemetry to evaluate potential predictors of lamprey passage success at McNary Dam, located ~469 river kilometres (rkm) from the Pacific Ocean. The tagged population included 276 lampreys collected at McNary Dam and 53 collected at Bonneville Dam (rkm 235) that migrated to McNary Dam. McNary Dam passage efficiency was similar for the two samples, with multiyear estimates of 0.65 and 0.75, respectively. Larger‐bodied lampreys and those with earlier migration timing were more likely to return to McNary Dam after release, to pass the dam and to be detected upstream from McNary reservoir. Far more lampreys entered the upper Columbia River than the Snake River, suggesting that environmental cues (e.g., water discharge, temperature) or conspecific cues (e.g., pheromone concentrations) affect lamprey distribution above this large confluence. Overall, results indicate that Pacific lamprey passage success at barriers depends on a combination of individual lamprey traits plus seasonal and site‐specific effects on behaviour. 相似文献
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