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Sci Rep ; 7(1): 8820, 2017 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-28821782


The island rule describes a graded trend in insular populations of vertebrates from gigantism in small species to dwarfism in large species. The dwarfing of large mammals on islands has been observed both in the present fauna and in the fossil record. Elephants, hippopotami, deer, and other species became dwarfed on islands scattered all over the world, from the Mediterranean Sea to Indonesia, from the Eastern to Western Pacific Ocean, from the Caribbean to Canary Islands. The most rapid and well documented cases of island dwarfing known thus far took place over thousands of years. Here, we describe a rapid example of dwarfing of a large mammal - the feral cattle of Amsterdam Island, southern Indian Ocean, which dwarfed to about three quarters of its body size in slightly more than one century. This population provides us with a rare opportunity to assess the rapidity of demographic, life history, and morphological responses of large mammals to a very isolated and ecologically simple, insular environment.

Nanismo , Animais , Evolução Biológica , Bovinos , Meio Ambiente , Feminino , Masculino , Fenótipo
Q Rev Biol ; 84(4): 357-90, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20039528


Biogeographers study all patterns in the geographic variation of life, from the spatial variation in genetic and physiological characteristics of cells and individuals, to the diversity and dynamics of biological communities among continental biotas or across oceanic archipelagoes. The field of island biogeography, in particular, has provided some genuinely transformative insights for the biological sciences, especially ecology and evolutionary biology. Our purpose here is to review the historical development of island biogeography theory during the 20th century by identifying the common threads that run through four sets of contributions made during this period, including those by Eugene Gordon Munroe (1948, 1953), Edward O. Wilson (1959, 1961), Frank W. Preston (1962a,b), and the seminal collaborations between Wilson and Robert H. MacArthur (1963, 1967), which revolutionized the field and served as its paradigm for nearly four decades. This epistemological account not only reviews the intriguing history of island theory, but it also includes fundamental lessons for advancing science through transformative integrations. Indeed, as is likely the case with many disciplines, island theory advanced not as a simple accumulation of facts and an orderly succession of theories and paradigms, but rather in fits and starts through a reticulating phylogeny of ideas and alternating periods of specialization and reintegration. We conclude this review with a summary of the salient features of this scientific revolution in the contest of Kuhn's structure, which strongly influenced theoretical advances during this period, and we then describe some of the fundamental assumptions and tenets of an emerging reintegration of island biogeography theory.

Ecossistema , Filogenia , Topografia Médica , Animais , Biodiversidade , Dinâmica Populacional
Conserv Biol ; 21(4): 1059-69, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17650255


Body size is perhaps the most important trait of an organism, affecting all of its physiological and ecological processes and, therefore, fundamentally influencing its ability to survive and reproduce in different environments, including those that have been modified by human activities. We tested the hypothesis that anthropogenic transformation of old-growth forest landscapes can result in significant intraspecific changes in body size of resident biotas. We collected data on five species of nonvolant mammals (common deer mouse[Peromyscus maniculatus], northwestern deer mouse[P. keeni], southern red-backed vole[Clethrionomys gapperi], montane shrew[Sorex monticolus], and Trowbridge's shrew[S. trowbridgii]) to test whether body size (mass and length) of these species varied across types of land cover (macrohabitats) and along elevational gradients of the fragmented, temperate rainforest of Olympic National Forest (Washington, U.S.A.). We measured 2168 and 1134 individuals for body mass and body length, respectively. Three species (P. keeni, S. monticolus, and S. trowbridgii) exhibited significantly different body size among macrohabitats: individuals from fragments were smaller than those in old-growth corridors and those in more extensive stands of old-growth forest. Body size of P. keeni was significantly correlated with elevation along corridors, peaking near the medial reaches of the corridors. The effects of anthropogenic transformations of this landscape of old-growth, temperate rainforest, although not universal among the five species, were significant and rapid-developing in just a few decades following tree harvests. Thus, anthropogenic fragmentation may influence not only the diversity, species composition, and densities of local biotas, but also one of the most fundamental and defining characteristics of native species-their body size.

Arvicolinae/fisiologia , Tamanho Corporal/fisiologia , Ecossistema , Musaranhos/fisiologia , Árvores , Animais , Clima , Conservação de Recursos Energéticos , Feminino , Masculino , Camundongos , Washington
Ribeirão Preto; FUNPEC; 2. ed rev. e ampl; 2006. 691 p.
Monografia em Português | LILACS | ID: lil-760840
Ribeirão Preto; FUNPEC; 2. ed rev. e ampl; 2006. 691 p.
Monografia em Português | Coleciona SUS, LILACS, Coleciona SUS | ID: biblio-941220
Sunderland; Sinauer Associates; 3. ed; 2006. 845 p. ilus.
Monografia em Inglês | Coleciona SUS, Coleciona SUS | ID: biblio-935893
Oecologia ; 138(4): 592-602, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-14685848


We tested the hypothesis that black-tailed prairie dogs (Cynomys ludovicianus) influence avian community structure on the shortgrass prairie. We surveyed 36 prairie dog towns and 36 paired sites without prairie dogs during summer and fall of 1997, 1998, and 1999 in the Oklahoma Panhandle. Our surveys totaled 9,040 individual observations for 73 avian species. Significantly distinct avian communities were present on prairie dog towns when compared to sites within four different macrohabitats of the surrounding landscape: open rangeland, scrub/sandsage (Artemisia filifolia) habitats, Conservation Reserve Program (CRP) plots, and fallow crop fields. Relative densities of all bird species combined was higher on prairie dog towns versus paired sites in summer and fall. Mean species richness of birds was significantly higher on prairie dog towns than paired sites during summer, but there were no significant differences in fall. Open rangeland had the highest mean species richness in fall. Assemblages of avian communities differed significantly between prairie dog towns and the four macrohabitat types during summer. Burrowing owls (Athene cunicularia), killdeer (Charadrius vociferous), horned larks (Eremophila alpestris), and meadowlarks (Sturnella spp.) were positively and significantly associated with prairie dog towns during summer, while horned larks and ferruginous hawks (Buteo regalis) were significantly associated with prairie dog towns during fall. Even in their current remnant state, black-tailed prairie dogs continue to play a significant role in the assembly of ecological communities across the Great Plains. Conservation of prairie dogs goes well beyond a single species, and is an important strategy for the preservation of the prairie ecosystem as a whole.

Aves/classificação , Ecossistema , Sciuridae , Animais , Oklahoma , Poaceae , Dinâmica Populacional
Oecologia ; 61(3): 376-382, 1984 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28311066


In this paper I reviewed mammalian biogeography for 19 archipelagoes and tested the applicability of the equilibrium theory of island biogeography to mammalian faunas in general. The species-area and species-isolation relationships of terrestrial mammals were consistent with the basic predictions of the equilibrium theory. The z-values for the species-area relationship did not differ significantly from Preston's canonical value of 0.26 (P>0.50), and the modal z-value for non-volant mammals was 0.25. Moreover, z-values increased with isolation and decreased with vagility of the fauna in question. Furthermore, the strength of the species-isolation correlation was negatively correlated with island area and vagility (P<0.001).

Oecologia ; 54(1): 72-75, 1982 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28310995


The species-area and species-distance relationships of terrestrial mammals in the Thousand Island Region of the St. Lawrence River are totally consistent with the basic predictions of the equilibrium theory of island biogeography. The power model provides the best fit for the species-area relationship, and the z-value of 0.305 does not differ significantly from Preston's canonical value (0.26). Distance (D) is a normal determinant (Sαe -D 2) of mammalian richness, and 93% of the variability in richness is accounted for by island area and isolation. The high z-values and poor species-distance correlations reported in previous studies of mammalian island biogeography, rather than evidencing non-equilibrium, are predictions consistent with the equilibrium theory for distant archipelagoes or, equivalently, poor immigrators such as mammals.