Multi-scale response of wetland bird assemblages to landscape patterns on a Neotropical island: when wetland type matters more than size

Abstract

Understanding wetland bird responses to landscape patterns is central for wetland management and bird conservation. This is particularly relevant on islands, where most of the global extinctions have occurred. In this study, we identified landscape patterns in wetlands on Cozumel Island that best explained abundance of birds grouped in 13 trophic guilds at 3 spatial scales (145, 300, and 850 m radius from count points). By using ordination techniques and generalized linear models we found a scale dependent dissimilarity between the use of extensive estuarine and small inland brackish wetlands. At finer spatial scales, abundance of birds in trophic guilds that mainly use estuarine or inland brackish wetlands was associated with the proportion of land cover types of the corresponding wetland type, whereas at the broadest spatial scale, connectivity of such land cover types was more important. Abundance of birds in trophic guilds that do not prefer any particular type of wetland did not show any relationship with landscape diversity nor connectivity of land cover types, but their abundance showed relationships with specific land cover types from both estuarine and inland brackish wetlands as well as with bordering wetland vegetation. We concluded that the presence of continuous extents of land cover types of both extensive estuarine and small inland brackish wetlands are important for the conservation of distinct wetland bird assemblages on Cozumel Island.