Marine subsidies in the extremely arid islands of the northern Gulf of California have been shown to be important enhancing primary productivity and fueling the terrestrial food webs. This effect has been proved in plants, insects, lizards and rodents. The aims of our study were first to determine whether insectivorous lizards from a wide array of islands, including some in the central and southern part of the Gulf, are consuming marine derived products, and secondly to assess its impact on herbivore lizards as well. We hypothesized that the availability and use of marine nutrients for lizards

Predators influence ecosystem functioning through consumptive and non-consumptive effects. Recent studies suggest that predators can also be an essential source of limiting nutrients in ecosystems such as coral reefs, potentially influencing prey ecology through nutrient input via their excreta. With rising commercial fishery, mesopredatory fishes are being selectively harvested from reefs. Yet, there is incomplete knowledge of the consequences of this extraction on essential ecosystem processes. Using field experiments and observations, we examined how mesopredatory fishes influence herbivory along a fishing-induced mesopredatory fish biomass gradient in the Lakshadweep Archipelago in the northern Indian Ocean. We found that mesopredatory fish excreta have greater proportion of phosphorus than nitrogen. Along the gradient, primary and secondary productivity increased, after accounting for pelagic nutrient subsidies. Further, herbivory rates increased with increasing mesopredator biomass, while prey anti-predator response remained unchanged. Our results suggest that mesopredator-induced alterations of nutrient stoichiometry stimulate primary and secondary productivity and enhance herbivory in phosphorus-limited coral reefs, particularly in systems experiencing mesopredator release following selective fishing of apex predators. Our study shifts focus from the traditional top-down role of predators, highlighting an overlooked bottom-up pathway by which mesopredators can influence ecosystem functioning. Global decline of predators could modify ecosystem processes in ways that are yet unknown, leaving them increasingly vulnerable to future disturbances.

Marine-derived nutrients can increase primary productivity and change species composition of terrestrial plant communities in coastal and riverine ecosystems. We hypothesized that sea nutrient subsidies have a positive effect on nitrogen assimilation and seedling survival of non-nitrogen fixing species, increasing the relative abundance of non-nitrogen fixing species close to seashore. Moreover, we proposed that herbivores can alter the effects of nutrient supplementation by preferentially feeding on high nutrient plants. We studied the effects of nutrient fertilization by seabird guano on tre

These nutrients dramatically alter terrestrial ecosystem functioning and dynamics and can support increased primary and secondary productivity. However A marine coastal ecosystem is a marine ecosystem which occurs where the land meets the ocean. Worldwide there is about 620,000 kilometres (390,000 mi) of coastline. Coastal habitats extend to the margins of the continental shelves, occupying about 7 percent of the ocean surface area. Marine coastal ecosystems include many very different types of marine habitats, each with their own characteristics Coastal waters include the waters in estuaries and over continental shelves. They occupy about 8 percent of the total ocean area and account for about half of all the ocean productivity. The key nutrients determining eutrophication are nitrogen in coastal waters and phosphorus in lakes. Both are found in high concentrations in guano (seabird feces), which acts as a fertilizer for the surrounding ocean or an adjacent lake. Uric acid is the dominant nitrogen compound, and during its mineralization different nitrogen forms are produced. Ecosystems, even those with seemingly distinct borders, rarely function independently of other adjacent systems. Ecologists are increasingly recognizing the important effects that cross-ecosystem transport of energy and nutrients have on plant and animal populations and communities. A well known example of this is how seabirds concentrate marine-derived nutrients on breeding islands in the form of feces (guano) which contains ~15–20% nitrogen (N), as well as 10% phosphorus. These nutrients dramatically alter terrestrial ecosystem functioning and dynamics and can support increased primary and secondary productivity. However, although many studies have demonstrated nitrogen enrichment of terrestrial components due to guano deposition across various taxonomic groups, only a few have studied its retroaction on marine ecosystems and most of these studies were restricted to temperate regions and high nutrient waters. In the tropics, coral reefs can be found adjacent to islands with large populations of breeding seabirds, and could be potentially affected by local nutrient enrichment due to the transport of seabird-derived nutrients in surrounding waters. Studies on the influence of guano on tropical marine ecosystems suggest nitrogen from guano enriches seawater and reef primary producers. Reef building corals have essential nitrogen needs and, thriving in nutrient-poor tropical waters where nitrogen is a major limiting nutrient for primary productivity, they have developed specific adaptations for conserving this element. Their establishment and maintenance are partly due to their symbiosis with unicellular dinoflagellates, Symbiodinium…