CapsuleWithin the UKs largest lowland Eurasian Curlew Numenius arquata population, Curlew preferentially nested on physically-disturbed (treated) than undisturbed (control) grassland, and low nest survival rates were primarily attributable to Red Fox Vulpes vulpes. AimsTo inform conservation interventions for Curlew within semi-natural lowland drygrassland landscapes. MethodsAcross a 3,700 ha lowland dry-grassland landscape, over two years, effects of grounddisturbance management on Curlew nest placement (n=41) were examined using GLMs controlling for vegetation strata; effects of site and management on nest survival (n=44) were examined controlling for lay date and year. Nest predator identity was investigated using temperature sensors (n=28) and nest cameras (n=10). ResultsCurlews were five times more likely to nest on physically-disturbed than undisturbed grassland. Nest survival (overall mean 0.24 ± 0.07, SE) was not influenced by year or ground-disturbance but declined with lay date and differed markedly between the two sites, consistent with predator control. Predation accounted for 29/32 of failed nests and was predominantly at night (17/23 cases where timing was known, p<0.001), consistent with mammalian predators. Cameras indicated Foxes to be the main predator (4/5 cases). Overall breeding productivity was 0.16 ± 0.01 (SE) chicks per nesting attempt. ConclusionCurlew suffered from unsustainably high rates of nest predation primarily attributable to Foxes. A combination of perimeter fencing and lethal predator control appeared to improve nest success at one site. Ground-disturbance treatment could encourage nesting attempts in areas managed to minimise predator density.
Translocation of captive-bred individuals to reinforce wild populations may be an important conservation approach for some species, but can be detrimental when employed to boost exploited wild populations, particularly where repeated long-term reinforcement aims to compensate for repeated unregulated offtake. We review evidence that captive breeding alters multiple physiological, life-history and temperamental traits through founder effects, genetic drift and unintended adaption to captivity; degrades learnt behaviours; and compromises biogeography, population structure and viability through introgression. We highlight these risks for the globally threatened African houbara Chlamydotis undulata and Asian houbara C. macqueenii, 2 bustard species hunted throughout much of their ranges and now subject to multiple large-scale captive-breeding programmes and translocations. In eastern Morocco, annual releases of captive-bred African houbara are 2‒3 times higher than original wild numbers, but no investigation of their potentially deleterious effects has, to our knowledge, been published, although most wild populations may now have been replaced by captive-bred domestic stock, which are reportedly not self-sustaining. Despite multiple decades of reinforcement, we are not aware of any analysis of the contribution of captive breeding to African houbara population dynamics, or of the genomic consequences. Asian houbara release programmes may also be promoting rather than preventing declines, and need to contextualise themselves through rigorous analyses of wild population numbers, demographic rates and threats, maintenance of phylogeographic concordance of released with supplemented populations, profiling of traits crucial to survival and the measurement and modelling of the impacts of reinforcement on physiological and behavioural fitness of wild populations.
kill, orderliness, productivity and, most of all, industry lie at the heart of bee mythology. Hence, for exam ple, this image in philosopher Bernard de Mandeville's The Fable of the Bees (1714): A Spacious Hive well stockt with Bees, That liv' d in Luxury and Ease; And yet as fam' d for Laws and Arms, As yielding large and early Swarms; Was counted the great Nursery Of Sciences and Industry.
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