Mosaic-level inference of the impact of land cover changes in agricultural landscapes on biodiversity: a case-study with a threatened grassland bird.
Changes in land use/land cover are a major driver of biodiversity change in the Mediterranean region. Understanding how animal populations respond to these landscape changes often requires using landscape mosaics as the unit of investigation, but few previous studies have measured both response and explanatory variables at the land mosaic level. Here, we used a "whole-landscape" approach to assess the influence of regional variation in the land cover composition of 81 farmland mosaics (mean area of 2900 ha) on the population density of a threatened bird, the little bustard (Tetrax tetrax), in southern Portugal. Results showed that ca. 50% of the regional variability in the density of little bustards could be explained by three variables summarising the land cover composition and diversity in the studied mosaics. Little bustard breeding males attained higher population density in land mosaics with a low land cover diversity, with less forests, and dominated by grasslands. Land mosaic composition gradients showed that agricultural intensification was not reflected in a loss of land cover diversity, as in many other regions of Europe. On the contrary, it led to the introduction of new land cover types in homogenous farmland, which increased land cover diversity but reduced overall landscape suitability for the species. Based on these results, the impact of recent land cover changes in Europe on the little bustard populations is evaluated.
Centre for Applied Ecology Prof. Baeta Neves, Institute of Agronomy, Technical University of Lisbon, Lisbon, Portugal. fmoreira@isa.utl.pt
Francisco
F
Moreira
João P
JP
Silva
Beatriz
B
Estanque
Jorge M
JM
Palmeirim
Miguel
M
Lecoq
Márcia
M
Pinto
Domingos
D
Leitão
Ivan
I
Alonso
Rui
R
Pedroso
Eduardo
E
Santos
Teresa
T
Catry
Patricia
P
Silva
Inês
I
Henriques
Ana
A
Delgado
D000383:Agriculture; D000818:Animals; D044822:Biodiversity; D001717:Birds; D017753:Ecosystem; D008297:Male; D019083:Mediterranean Region; D011156:Population Density; D011157:Population Dynamics