Trend in the Community Specialization Index of birds in Mediterranean Wetlands over time.
How to read this graph: a decrease in the CSI means that the bird community of Mediterranean wetlands has changed over time with specialists representing now a smaller proportion of the community than in 1970. Conversely, generalists are now better represented than in the past.
The significant negative trend in the CSI reveals that land-use changes in the last decades have reduced the diversity of bird species in Mediterranean wetlands.
Human-induced changes have favoured generalists to the detriment of specialists. Some species underwent a large decline as the habitat they are specialised in was largely converted. This is the case e.g. for species living exclusively in reedbeds or seasonal wetlands. On the opposite, some generalists have adapted very well to the large-scale
changes happening in wetlands by taking advantage of new and abundant food resources (e.g. intensive crop farming, wetland eutrophication) or of the multiplication of artificial wetlands flooded all year-round (e.g. reservoirs, fish ponds).
These changes are worrying as it means that bird assemblages are decreasingly di- verse and original over time, with few banal species (generalists) replacing many other species (specialists), rarer and which make the specificity of Mediterranean waterbird community. These land-use changes include the loss, modification and degradation of natural wetlands due to pollution, fragmentation, but also an artificial management that does not reproduce the original functioning of Mediterranean wetlands (characterized by a high ecological variability).
|Time-wise coverage: 1970 - 2009
Geographical coverage: Mediterranean basin
Main sources of data: