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Human footprint and vulture mortality

Events of non-natural mortality in human-dominated landscapes are especially challenging for populations of large vertebrates with K strategies. Among birds, vultures are one of the most threatened groups experiencing sharp population declines due to non-natural mortality. Factors causing non-natural mortality are usually studied separately. However, the potential use of an integrated index able to predict large-scale mortality risks of avian scavengers could be especially useful for planning conservation strategies. Here, the Human Footprint index was used to examine the impact of landscape anthropization on the survival rates of 66 GPS-tagged adult Eurasian griffon vultures (Gyps fulvus) in two Spanish regions. Foraging in more anthropized areas resulted in a significantly higher individual mortality risk mainly due to collisions with vehicles, poisonings, electrocutions and fatalities with wind turbines. Mean yearly survival rates were estimated at 0.817 and 0.968 for individuals from the more and less anthropized regions, respectively. Additional research should investigate whether some vulture populations could be acting as sinks unnoticed due to metapopulation dynamics. From a broader point of view, this study shows that a straightforward Human Footprint was a useful index to predict the survival of top scavengers and can be highly applicable to planning large-scale conservation measures. informacion[at] Arrondo et al (2020) Landscape anthropization shapes the survival of a top avian scavenger. Biodivers Conserv.
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Trait evolution across the tree?of?life of freshwater macroinvertebrates

Trait evolution across the tree?of?life of freshwater macroinvertebrates

The rates of species and trait diversification vary across the Tree?of?Life and over time. Whereas species richness and clade age generally are decoupled, the correlation of accumulated trait diversity of clades (trait disparity) with clade age remains poorly explored. Total trait disparity may be coupled with clade age if the growth of disparity (disparification) within and across clades is continuous with time in an additive niche expansion process (linear?cumulative model), or alternatively if the rate of trait disparification varies over time and decreases as ecological space becomes gradually saturated (disparity?dependent model). Using a clock?calibrated phylogenetic tree for 143 freshwater macroinvertebrate families and richness and trait databases covering more than 6400 species, trait disparity in 18 independent clades that successively transitioned to freshwater ecosystems were measured and its relation with clade age was analyzed. A positive correlation between clade age and total disparity within clades was found, but no relationship for most individual traits. Traits unique to freshwater lifestyle were highly variable within older clades, while disparity in younger clades shifted towards partially terrestrial lifestyles and saline tolerance to occupy habitats previously inaccessible or underutilized. These results argue that constraints from incumbent lineages limit trait disparity in younger clades that evolved for filling unoccupied regions of the trait space, which suggests that trait disparification may follow a disparity?dependent model. Overall, an empirical pattern is provided that reveals the potential of the disparity?dependent model for understanding fundamental processes shaping trait dynamics across the Tree?of?Life. informacion[at] Múrria et al (2018) Ecological constraints from incumbent clades drive trait evolution across the tree?of?life of freshwater macroinvertebrates. Ecography 41(7): 1049-1063