Summary1. The movement of materials and organisms between ecosystems is a common process in nature. 2. In the present study we investigate the hypothesis that the transport of nutrients by low-mobility species and their effect on terrestrial ecosystems depends on habitat topography. Specifically, we hypothesized that the influence of a marine organism with low mobility on terrestrial environments would be spatially restricted. 3. To address this hypothesis we analysed the distribution (both geographical and local scales) of Galapagos sea lion colonies, and quantified the spatial extent of their influence on terrestrial ecosystems (soil and plants). 4. Our results showed that the influence of Z. wollebaecki on Galapagos terrestrial habitats is restricted to shorelines with low elevations, but that it is it is geographically ubiquitous across the Archipelago. 5. Our study demonstrated that Z. wollebaecki is an effective vector for the transport of marine nutrients to terrestrial ecosystems. Transported nutrients occur in high concentrations in the soils and are used by shoreline plants. These effects are spatially restricted to the areas where seals occur and the most parsimonious explanatory variable for these patterns is the islands' topography (or elevation).

Summary 1.The movement of materials and organisms between ecosystems is a common process in nature. 2. In the present study we investigate the hypothesis that the movement of consumers between ecosystems depends not only on the differences in productivity between ecosystems and prey availability, but also on these animals' biological characteristics. 3. To address this hypothesis we investigated the changes in abundance, habitat utilization and diet of the lizard Microlophus atacamensis along its geographical range on the coast of the Atacama Desert. Within this range, intertidal rocky shore communities do not show important variations in their species composition and abundance, but terrestrial communities show a steep gradient of productivity associated with the increase in rainfall from north to south. 4. Our results show that the use of intertidal habitats and the consumption of intertidal prey by M. atacamensis change within its geographical range: in the North, the species uses intertidal areas and behaves as an herbivore consuming mostly algae, whereas in the South it expends most of the time in terrestrial habitats as a carnivore mainly of arthropods. 5. Our study gives new evidence for cross-ecosystem connections created by consumer movement between habitats of contrasting but variable productivity levels.