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International Perspectives on Global Environmental Change Part 5

Tham khảo tài liệu 'international perspectives on global environmental change part 5', khoa học tự nhiên, công nghệ sinh học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | How Did Past Environmental Change Affect Carnivore Diversity and Home-Range-Size in Spain 109 Fig. 1. Geographical distribution of the selected localities from Spain. Van Valkenburgh 1985 1988 1989 confined large terrestrial carnivore guilds to predators weighting 7 kg or more jackal size and larger proposing this size threshold because of the evidence in extant species for strong competitive interactions among carnivores larger than 7 kg being weaker among smaller carnivores in addition the representation of large carnivores in the fossil record is better. On the other hand because larger predators achieve a higher net gain rate by concentrating on large prey Carbone et al. 2007 predicted the threshold of 14.5 kg where predators switch from small to large prey. We follow this criterion and restrict our study to species of the three families that include top terrestrial predators Canidae Felidae and Hyaenidae. Ursidae are excluded due to their omnivorous feeding behaviour that rarely includes meat. For each species we compiled data of its presence in fossil sites body-size diet and preferred habitat. We used a taxon-free characterization by means of two ecological criteria of classification. According to the feeding behavior species were classified in two trophic categories 1 Carnivore C hypercarnivores with a diet that consists of 70 or more flesh meat bone-eaters bone-crushers and scavenging bone-crackers and 2 CarnivoreOmnivore OM including flesh-eaters with less than 10 flesh in their diet taxa feeding on invertebrates and occasionally on fruit. Concerning the preferred habitat three major ecological categories were considered 1 Forest dwellers FH taxa inhabiting forest closed woodland bushland Mediterranean macchia open woodland and miscellaneous woodland 2 Ubiquitous MXH including more flexible taxa inhabitants of shrubland or woodland as well as open landscape or at the edge of both and 3 Open landscape dwellers OH including taxa inhabiting grassland steppe