Does landscape diversity influence species fitness in farmland plants ?
Résumé
In agriculture, landscape management research has proven extremely valuable for explaining species amount, such as how species capture and utilize changed landscape resources to maintain population size and community diversity. What is surprising is the apparent lack of comparable studies on the effects of landscape properties and management on species fitness. Here, we search for "pathological" situations where landscape effects on farmland plant amount mask significantly different effects on fitness. We examined the case of 83 weed species in 256 fields distributed across the UK national scale. Whether at the local scale of the neighborhood or the larger scale of 2 km, we find landscape effects on species amounts indicate correctly the direction of landscape effects on fitness. Only for five species did we find evidence of pathology, where positive effects of landscape on species amount would mask a negative impact on species fitness; a potential extinction debt. Our results would broadly suggest that for the great majority of weed species, landscape management could continue to use, solely, metrics of species amount. However, there is a future research need to understand why there are contrasted fitness responses in the five weed species.