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Consequences of the defaunation of the Canarian frugivorous lizards

Defaunation of large-bodied frugivores could be causing severe losses of crucial ecosystem functions such as seed dispersal. The immediate ecological consequences may include alteration or even collapse of seed-mediated gene flow affecting plant population connectivity, with impacts on the regional scale distribution of genetic variation. Yet these far-reaching consequences of defaunation remain understudied. This study tested whether human-induced defaunation of the Canarian frugivorous lizards altered within-island population connectivity and the amount and large-scale distribution of genetic variation of Neochamaelea pulverulenta, which relies exclusively on these lizards for seed dispersal. Individual plant genotypes from 80 populations were extensively sampled spanning the full geographic range of the plant to examine their genetic diversity, population-genetic network topologies, and the patterns of isolation both by distance (IBD) and resistance (IBR) across three ecological scenarios. Plant genetic diversity appeared unaffected by defaunation-mediated downsizing of frugivorous lizards. However, it was found reduced overall plant population connectivity together with an increased isolation by distance within the most defaunated islands when compared with the scenario preserving the functionality of lizard-mediated seed dispersal. The results, with a significant effect of lizard downsizing, were robust when controlling for biotic/abiotic differences among the three islands by means of isolation by resistance models. These results provide valuable insights into the far-reaching consequences of the deterioration of mutualisms on plant population dynamics over very large spatial scales. Conservation of large-bodied frugivores is thus essential because their irreplaceable mutualistic dispersal services maintain an extensive movement of seeds across the landscape, crucial for maintaining the genetic cohesiveness of metapopulations and the adaptive potential of plant species across their entire geographic range. informacion[at]ebd.csic.es: Pérez-Méndez et al (2017) Persisting in defaunated landscapes: reduced plant population connectivity after seed dispersal collapse. J Ecol doi:10.1111/1365-2745.12848

 


http://onlinelibrary.wiley.com/doi/10.1111/1365-2745.12848/full
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Content with tag canary islands .

Consequences of the defaunation of the Canarian frugivorous lizards

Defaunation of large-bodied frugivores could be causing severe losses of crucial ecosystem functions such as seed dispersal. This study tested whether human-induced defaunation of the Canarian...

The spatial distribution of an insular cliff-nesting raptor community

The specific spatial distribution and habitat association are major issues in ecology and conservation. Nesting sites of five cliff-nesting raptors (Egyptian vulture [a locally extinct species],...

Downsized mutualisms: Consequences of seed dispersers’ body-size reduction for early plant recruitment

In this study the consequences of body-size reduction of Giant Canarian lizards (g. Gallotia, Lacertidae) on the recruitment of Neochamaelea pulverulenta (Rutaceae), an endemic shrub relying...

Nectar and pollen of the invasive century plant Agave americana as a food resource for endemic birds

Invasive species are one of the major causes of biodiversity loss, especially in island ecosystems. However, introduced plants can also bring positive effects to the ecosystem by providing feeding...