192 research outputs found
The density of the invertebrate summer fauna on the crowns of pine trees, Pinus sylvestris in the central part of the Netherlands.
Die Dichte der Sommerfauna der Invertebraten in den Kronen der Kiefern (außer Mikrolepidopteren, Aphiden, Psociden, Jassiden und Milben) wurde in den Jahren 1967-1971 für die Monate Juni, Juli, August und September ermittelt. Die Proben wurden den Bäumen entnommen, indem man Zweige vorsichtig in einen großen Sack schnitt. Nachdem die Tiere mit Kohlendioxyd getötet worden waren, wurden sie durch kräftiges Schütteln der Zweige über einem Tuch aus diesen entfernt.The density of the invertebrate fauna on the crowns of pine trees (microlepidoptera, aphids, psocids, jassids and mites excepted) has been assessed in June, July, August and September over the years 1967-1971. Trees have been sampled by cutting twigs and carefully putting them into a large sack. After having been killed by carbondioxyde the animals were dislodged from the twigs by shaking the latter thoroughly over a cloth
Dietary complexity and hidden costs of prey switching in a generalist top predator
Variation in predator diet is a critical aspect of food web stability, health, and population dynamics of predator/ prey communities. Quantifying diet, particularly among cryptic species, is extremely challenging, however, and differentiation between demographic subsets of populations is often overlooked. We used prey remains and data taken postmortem from otter Lutra lutra to determine the extent to which dietary variation in a top predator was associated with biotic, spatial, and temporal factors. Biotic data (e.g., sex, weight, and length) and stomach contents were taken from 610 otters found dead across England and Wales between 1994 and 2010. Prey remains were identified to species where possible, using published keys and reference materials. Multi‐model inference followed by model prediction was applied to test for and visualize the nature of associations. Evidence for widespread decline in the consumption of eels (Anguilla anguilla ) reflected known eel population declines. An association between eel consumption and otter body condition suggested negative consequences for otter nutrition. Consumption of Cottus gobio and stickleback spp. increased, but was unlikely to compensate (there was no association with body condition). More otters with empty stomachs were found over time. Otter sex, body length, and age‐class were important biotic predictors of the prey species found, and season, region, and distance from the coast were important abiotic predictors. Our study is unique in its multivariate nature, broad spatial scale, and long‐term dataset. Inclusion of biotic data allowed us to reveal important differences in costs and benefits of different prey types, and differences between demographic subsets of the population, overlaid on spatial and temporal variation. Such complexities in otter diet are likely to be paralleled in other predators, and detailed characterization of diet should not be overlooked in efforts to conserve wild populations
Foraging ecology of Eurasian lynx populations in southwest Asia: Conservation implications for a diet specialist
Intraspecific variation in key traits of widespread species can be hard to predict, if populations have been very little studied in most of the distribution range. Asian populations of the Eurasian lynx (Lynx lynx), one of the most widespread felids worldwide, are such a case in point. We investigated the diet of Eurasian lynx from feces collected Mediterranean, mixed forest‐steppe, and subalpine ecosystems of Turkey. We studied prey preferences and functional responses using prey densities obtained from Random Encounter Modelling. Our analysis revealed that the main prey was brown hare (Lepus europaeus) in all three areas (78%–99% of biomass consumed) and lynx showed a strong preference for brown hare (Chesson's selectivity index, α = 0.90–0.99). Cannibalism contributed at least 5% in two study areas. The type II functional response of lynx populations in Turkey was similar to the Canada lynx (Lynx canadensis) and daily food intake in grams per lynx matched that of Canada lynx and Iberian lynx (Lynx pardinus), both lagomorph specialists, rather than those of Eurasian lynx from Europe. Therefore, lynx in Turkey may be better described as a lagomorph specialist even though it coexists with ungulate prey. We suggest that ungulate‐based foraging ecology of Eurasian lynx in Europe may be a recent adjustment to the availability of high densities of ungulates and cannot be representative for other regions like Turkey. The status of lagomorphs should become an essential component of conservation activities targeted at Eurasian lynx or when using this species as a flagship species for landscape preservation
Morphological identification of animal hairs: Myths and misconceptions, possibilities and pitfalls
The examination of hair collected from crime scenes is an important and highly informative discipline relevant to many forensic investigations. However, the forensic identification of animal (non-human) hairs requires different skill sets and competencies to those required for human hair comparisons. The aim of this is paper is not only to highlight the intrinsic differences between forensic human hair comparison and forensic animal hair identification, but also discuss the utility and reliability of the two in the context of possibilities and pitfalls. It also addresses and dispels some of the more popular myths and misconceptions surrounding the microscopical examination of animal hairs. Furthermore, future directions of this discipline are explored through the proposal of recommendations for minimum standards for the morphological identification of animal hairs and the significance of the newly developed guidelines by SWGWILD is discussed
Neanderthal Use of Fish, Mammals, Birds, Starchy Plants and Wood 125-250,000 Years Ago
Neanderthals are most often portrayed as big game hunters who derived the vast majority of their diet from large terrestrial herbivores while birds, fish and plants are seen as relatively unimportant or beyond the capabilities of Neanderthals. Although evidence for exploitation of other resources (small mammals, birds, fish, shellfish, and plants) has been found at certain Neanderthal sites, these are typically dismissed as unusual exceptions. The general view suggests that Neanderthal diet may broaden with time, but that this only occurs sometime after 50,000 years ago. We present evidence, in the form of lithic residue and use-wear analyses, for an example of a broad-based subsistence for Neanderthals at the site of Payre, Ardèche, France (beginning of MIS 5/end of MIS 6 to beginning of MIS 7/end of MIS 8; approximately 125–250,000 years ago). In addition to large terrestrial herbivores, Neanderthals at Payre also exploited starchy plants, birds, and fish. These results demonstrate a varied subsistence already in place with early Neanderthals and suggest that our ideas of Neanderthal subsistence are biased by our dependence on the zooarchaeological record and a deep-seated intellectual emphasis on big game hunting
To eat or not to eat? The diet of the endangered iberian wolf (Canis lupus signatus) in a human- dominated landscape in central Portugal
Livestock predation by large carnivores and their persecution by local communities are
major conservation concerns. In order to prevent speculations and reduce conflicts, it is crucial
to get detailed and accurate data on predators’ dietary ecology, which is particularly important
in human dominated landscapes where livestock densities are high. This is the case
of the endangered Iberian wolf in Portugal, an endemic subspecies of the Iberian Peninsula,
which has seen its population distribution and abundance decline throughout the 20th century.
Accordingly, the diet of the Iberian wolf was analyzed, using scat analysis, in a humanized
landscape in central Portugal. From 2011 to 2014, a total of 295 wolf scats were
collected from transects distributed throughout the study area, prospected on a monthly
basis. Scat analysis indicated a high dependence of Iberian wolf on livestock. Domestic
goat predominated the diet (62% of the scats), followed by cow (20%) and sheep (13%); the
only wild ungulate present in the scat analysis was the wild boar (4% of the scats). Our results
show that even though livestock constitute most part of wolves diet, different livestock
species may represent different predation opportunities. We conclude that the high levels
of livestock consumption may be a result of low diversity and density of wild ungulates
that settles livestock as the only abundant prey for wolves. Our findings help on the understanding
of the Iberian wolf feeding ecology and have implications for conflict management
strategies. Finally, management implications are discussed and solutions are
recommended
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