MODEL-BASED GEOMORPHOLOGY OF MALPELO ISLAND AND SPATIAL DISTRIBUTION OF BREEDING SEABIRDS

Abstract

The spatial distribution of seabird nests present on Malpelo Island, the main characteristics of the islandʼs topography, and the types of substratum available for nesting were addressed using a Digital Elevation Model (DEM). The model is based on data from remote sensors (satellite images, aerial photography and panoramic photography), and from field data processed through a geographical information system. The nests of Sula granti prevail on the surfaces of Malpelo Island and neighboring islets, while those of the remaining species (S. sula, Creagrus furcatus, Anous stolidus, A. minutus and Gygis alba) are spatially restricted to the cliff margins and to crevices or caverns at different heights. The presence of terrestrial predators and predatory birds (Fregata spp.) seems to mainly explain the marginal distribution of other breeding species. The cartographic data presented here differ significantly from past and current representations, especially those concerning the islandʼs emerged surface and other geomorphologic features. This new cartographical information will support future studies on the terrestrial fauna and flora of Malpelo Island and its islets.