Articulo en Español e Ingles
(Spanish & English article)
(Spanish & English article)
Spiders are traditionally viewed as predators of insects. Zoologists from Switzerland and Australia have now published a study that shows: spiders all over the world also prey on fish. The academic journal PLOS ONE has just published the results.
|An orchid of the genus Paphiopedilum|
|Coquerel's Sifaka Lemur (www.newsobserver.com)|
|Lemur Pigmeo (Microcebus myoxinus)|
A specialist animal, the koala only lives in and eats the leaves of eucalyptus trees.
Specialization puts species at extreme risk
Human activities and environmental changes are driving many species to extinction. Species that exhibit a narrow environmental tolerance (specialist species) are particularly vulnerable and are currently declining worldwide. Their extinction strongly modifies the species composition of ecosystems. We can therefore observe the thriving of species with wide environmental tolerance (generalist species). For the maintenance of biodiversity and for the design of adapted management strategies it is crucial to understand which factors drive the maintenance of specialist species in ecosystems.
L. Büchi and S. Vuilleumier of the University of Lausanne in Switzerland have analyzed a model to identify the factors impacting the coexistence of specialist and generalist species. Two key factors have a drastic influence on the species composition of communities: species’ dispersal ability and the number of interacting species. Low dispersal limits the spread of specialist species, as their narrow environmental tolerance creates barriers that prevent them from reaching other favorable habitats. In contrast, it favors generalist species which are able to disperse gradually to neighboring habitats thanks to their higher environmental tolerance. When the number of interacting species is large, more specialist species are found as they have a strong advantage over generalist species in their habitats. Ecosystem loss and fragmentation might then drive specialist species to extinction as these factors limit species dispersal and reduce the number of species in ecosystems.
This work elucidates how species with different environmental tolerances can coexist together. In addition, it provides new insights into the design of conservation and management strategies. In particular, the future survival of specialist species relies on the conservation of whole ecosystems and the maintenance of high connectivity between them.
|Ballenas muertas a bordo de un barco factoría japonés en aguas del océano antártico|
|El mosquito Aedes aegypti, transmisor del Dengue y de la Fiebre amarilla|
|Macho y Hembra de Salmón del Atlántico. (Imagen de eceravoloflyfishing.com.ar)|
|Hormiga Loca Rasberry (Nylanderia fulva)|