Habitat-suitability modelling to assess the effects of land-use changes on Dupont’s lark Chersophilus duponti: A case study in the Layna Important Bird Area

Abstract

Habitat-suitability modelling is being increasingly used as a tool for conservation biology.Although studies at large spatial scales are more appropriate for reserve design and management, there is a scarcity of published work on local, high-resolution applications of such models. In this work we develop high-resolution habitat models (1 ha) and study habitat preferences (focal points) of Dupont's lark Chersophilus duponti, an endangered shrubsteppe passerine, in the partially overlapping Special Protected Area for birds (SPA) and Important Bird Area (IBA) of ''pá ramos de Layna'' (NW Spain), to assess both the adequacy of the reserve's limits and the effect of land-use changes on the species' population size.Both analytical approaches show that the Dupont's lark favours flat areas characterized by small shrubs with bare ground, so that, for example, a conversion of dry crops to shrubs promoted by agri-environment schemes under CAP could increase the population size up to 80%. Although the IBA and SPA are similar in size -as compelled by EU environmental policy -the latter shows rugged topography typically avoided by the species. We further discuss the possible conflict between EU environmental and agricultural policies on the conservation of this species and suggest it can be addressed with our study approach.

Short-Term Effects of a Wildfire on the Endangered Dupont's LarkChersophilus dupontiin an Arid Shrub-Steppe of Central Spain

“…Habitat selection studies in the same Layna páramos that include our study area (Seoane et al 2006) found that Dupont's Larks select habitat patches with about 35% cover of medium-sized shrubs (25-50cm), and similar values have been obtained by Garza & Suárez (1990) in other Spanish localities. Radio-tracking of marked individuals also in Layna páramos showed that Genista pumila, which represents nearly 60% of scrubs between 20 cm and 40 cm in our study area, accounted for 90% of locations (Garza et al 2005).…”

“…One important difference between these ecosystems and our study area is that they are dominated by grasslands, which recover faster than scrubs as our results for the second spring after fire have shown. However, as stated previously, in Spain a continuous grass cover is sub-optimal for the species that also selects for some percentage of bare ground (Seoane et al 2006). In this country just a few populations of Dupont's Lark inhabit alpha grass Stipa tenacissima steppes while most North African populations (90%) are located in areas of this vegetation type (García et al 2008, Suárez 2010.…”

“…This process could take at least four years if the results of studies on other Mediterranean shrubs were applicable to our study area (Tárrega et al 2001, Götzenberger et al 2003, since Genista pumila has not been studied to date. Moreover, given that grasslands are considered a sub-optimal habitat (Seoane et al 2006), the huge increase in grass cover in the second year after fire may contribute to declining habitat quality. Thus, although the effect of fire may be reversible, in the short term habitat quality is seriously reduced for several years, which could be due both to the disappearance of appropriate nesting substrate (Renwald 1977, Prodon & Pons 1993, Pons & Prodon 1996 and the shortage of food, which particularly affects insectivorous birds (Pons & Prodon 1996.…”

“…In Europe, Dupont's Lark is restricted to low scrub areas in Spain (Garza & Suárez 1990, Seoane et al 2006, where its populations have been reduced by 50% over the last 20 years to only 2,200 pairs and several populations have become extinct (Tella et al 2005, Suárez 2010). Agricultural intensification, habitat loss, fragmentation, and reduced grazing pressure are the principal factors responsible for this decline (Suárez 2010), but others not previously considered, such as the effects of fire, may also be involved.…”

Usefulness of coarse grain data on forest management to improve bird abundance models

“…Maiorano et al 2006;Rondinini et al 2006;Zielinski et al 2006;Tapia et al 2007) or assess the effects of environmental changes (e.g. Berry et al 2002;Thuiller 2003;Araú jo et al 2004;Puglisi et al 2005;Seoane et al 2006). For this reason, habitat suitability models (HSMs) have been increasingly used in the last decades.…”