Search results for "Edge effects"
showing 3 items of 3 documents
High variability of edge effects on forest vegetation diversity
2012
National audience; The influence of edges on vegetation diversity in forest fragments is an important issue for biodiversity conservation because of the large part of temperate woodlands concerned. In numerous empirical studies, a general pattern has been identified; it is described as two zones: the edge where plant distribution is linked to the distance from the forest border, the core area where the variability of vegetation is not linked to this distance. We present results of a study aiming at measuring the edge effects on vegetation in forest fragments in south-western France and at identifying potential factors of their variability. Vegetation was sampled in 28 transects constituted …
Human disturbance on Polylepis mountain forests in Peruvian Andes
2014
Vuoristot kattavat 20–25 % maapallon pinta-alasta ja niiden alueella kasvaa noin 28 % maapallon metsistä. Vuoristometsät ovat monella tapaa arvokkaita: ne tarjoavat useita ekosysteemipalveluita ja raaka-aineita sekä sisältävät suuren määrän elinympäristöjä ja eliölajeja. Ne ovat kuitenkin myös erittäin haavoittuvaisia. Resurssien optimoimiseksi tutkijat ovat nimenneet maapallolta hotspot-alueita, joilla esiintyy suuri määrä endeemisiä ja uhanalaisia lajeja. Ihmistoiminta vaikuttaa ekosysteemien luonnolliseen tilaan ollen merkittävä uhka hotspot-alueiden lajeille. Lisäksi ekosysteemin pirstaleisuus, laikun koko ja reunavaikutukset voivat vaikuttaa alueen lajirunsauteen ja sukupuuttovauhtiin.…
Data from: Population-level consequences of risky dispersal
2015
Achieving sufficient connectivity between populations is essential for persistence, but costs of dispersal may select against individual traits or behaviours that, if present, would improve connectivity. Existing dispersal models tend to ignore the multitude of risks to individuals: while many assess the effect of mortality costs, there is also a risk of failing to find new habitat, especially when the entire inhabitable area remains both small and fragmented. There are few known rules governing whether individuals evolve to disperse more, or less, than what is ideal for population connectivity and persistence. Here we aim to fill this gap, while also noting that evolution might not only pr…