This Series: Complexity & Transitions
This academic year at the CCSS we are holding two series of lectures. Under our 'Complexity & Transitions' series, we host guest lectures from researchers from a variety of discplines whose research cover falls under the theme transitions within complex systems. Please see our upcoming Events for details on our other lecture series.
Miguel Ángel Rodríguez is Professor of Ecology at University of Alcalá. His research covers macroecology, biodiversity and biogeography. In particular, his research focuses on habitat destruction and fragmentation, with a focus on the broad scale patterns of distribution of faunas and floras, alongside identifying the current and historical factors and processes that underlie them. Miguel is also a member of the Global Change Ecology and Evolution (GloCEE) group.
Does forest fragmentation increase species extinction threshold
The ongoing loss and fragmentation of natural habitats is a major cause of current biodiversity losses. A central hypothesis of fragmentation theory states that, when habitat loss leads to a constellation of separated habitat patches—in opposition to situations in which habitat remains are still spatially connected—both the extinction probability of a habitat specialist species (i.e. that thrives only in that habitat, be it e.g. a particular type of forest, grassland or marsh) and its habitat extinction threshold (i.e. the amount of habitat at which its occurrence probability falls to zero) increase. However, contradictory empirical results have fueled alternative hypotheses that assume a marginal or no role for fragmentation, and that imply that conservation efforts for preserving specialists should focus on how much habitat there is. In this talk, I shall present empirical evidence on the contrary and in support of the habitat extinction threshold hypothesis. I will present empirical results obtained using European-wide observational data for seven forest bird specialists, and that were used to parametrize logistic models of their occurrence probabilities as functions of forest amount and fragmentation. I will show that, even though all seven species can be classified as forest specialists using common standards, three react negatively to forest fragmentation, three do not respond to it, and even one does better in fragmented forests. I shall discuss this reflecting on the life-histories of each species and how their different traits may determine their individual reactions to the alteration of their habitats. Finally, I will end presenting yet unpublished maps of forest cover and fragmentation at global scale that may explain the proliferation of views supporting that fragmentation is unimportant for species conservation.
Location: Center for Complex Systems Studies, room 4.16, Minnaert Building, Leuvenlaan 4, De Uithof, Utrecht
The lunch is FREE for all participants, but please register before Wednesday 15th January.