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The role of conservative versus innovative nesting behavior on 25-year population expansion of an avian predator
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Orientador(es)
Resumo(s)
Species ranges often change in relation to multiple environmental and demographic
factors. Innovative behaviors may affect these changes by facilitating the use of novel
habitats, although this idea has been little explored. Here, we investigate the importance
of behavior during range change, using a 25-year
population expansion of
Bonelli’s eagle in southern Portugal. This unique population is almost exclusively tree
nesting, while all other populations in western Europe are predominantly cliff nesting.
During 1991–2014, we surveyed nest sites and estimated the year when each breeding
territory was established. We approximated the boundaries of 84 territories using
Dirichlet tessellation and mapped topography, land cover, and the density of human
infrastructures in buffers (250, 500, and 1,000 m) around nest and random sites. We
then compared environmental conditions at matching nest and random sites within
territories using conditional logistic regression, and used quantile regression to estimate
trends in nesting habitats in relation to the year of territory establishment. Most
nests (>85%, n = 197) were in eucalypts, maritime pines, and cork oaks. Nest sites
were farther from the nests of neighboring territories than random points, and they
were in areas with higher terrain roughness, lower cover by agricultural and built-up
areas, and lower road and powerline densities. Nesting habitat selection varied little
with year of territory establishment, although nesting in eucalypts increased, while
cliff nesting and cork oak nesting, and terrain roughness declined. Our results suggest
that the observed expansion of Bonelli’s eagles was facilitated by the tree nesting
behavior, which allowed the colonization of areas without cliffs. However, all but a
very few breeding pairs settled in habitats comparable to those of the initial population
nucleus, suggesting that after an initial trigger possibly facilitated by tree nesting,
the habitat selection remained largely conservative. Overall, our study supports recent
calls to incorporate information on behavior for understanding and predicting species
range shifts
Descrição
Palavras-chave
Aquila fasciata behavioral innovation conditional logistic regression conservation habitat selection quantile regression range expansion
Contexto Educativo
Citação
"Ecology and Evolution". May 2017, p.1-13
Editora
John Wiley and Sons