Effects of nesting waterbirds on nutrient levels in mangroves, Gulf of Fonseca, Honduras

Abstract

Mangroves provide numerous ecosystem services, including biodiversity values such as nesting sites for piscivorous waterbirds. High concentrations of pisicivoirous birds are hypothesized to affect ecosystem dynamics, yet few studies have examined their effects in mangroves. We examined the effects of nutrient enrichment by colonial waterbirds at a mangrove rookery in the Gulf of Fonseca, Honduras. We compared macronutrient levels in the vegetation and soils between two sites -a small island that hosted large numbers of roosting waterbirds and a nearby control site with little evidence of waterbird activity. Nest density at the rookery was 1721  469 nests ha -1 . Mangrove community structure and ecosystem carbon stocks were quantified by measuring above and belowground biomass, downed wood, and soil carbon. The nutrient input via bird guano deposition was quantified at each site. Rookery birds deposited 7.2  3.4 g m -2 day -1 guano dry weight. This large nutrient influx contributed to substantially higher concentrations of biologically important nutrients in the soil and mangrove leaves. These results suggest that colonial waterbirds may significantly impact mangrove ecology and productivity at local scales. Further research is needed to understand the effects of avian delivered nutrients on mangrove growth rates, nutrient export to adjacent waters, invertebrate communities, and mangrove associated fisheries.

Vectors with autonomy: what distinguishes animal‐mediated nutrient transport from abiotic vectors?

“…This is particularly true when organisms traverse ecosystem boundaries in ways that passive subsidies cannot, enhancing connectivity among systems. For instance, birds can serve as an important conduit of carbon across the marine–terrestrial ecosystem boundary (Anderson & Polis, ; Adame et al, ; McFadden et al, ; Otero et al, ). Classic examples are avian species that forage at sea and nest on islands relatively uninhabited by other organisms (Anderson & Polis, ).…”

Tropical wetlands, climate, and land-use change: adaptation and mitigation opportunities

“…Similar to C related ecosystem services, very little is known how management and land use change affect non-C related services. Although in the study by McFadden et al (2016) comparisons were not between mangroves under different management, the use of one system as a rookery showed significant changes to the soil pool of nutrients. Similar studies need to be conducted between unmanaged tropical wetlands and managed and changed systems to understand impacts on biodiversity, nutrient cycling, rearing of fish and shellfish and abatement potential for wind and waves along coastlines.…”

“…As a result, conservation of these important ecosystems should be a priority. McFadden et al (2016) conducted a study assessing the nutrient enrichment of water bird nesting sites in mangrove ecosystems of Honduras. Nutrient deposition, and nutrients in soil and vegetation were compared between a site within a nesting colony and an adjacent site without a nesting colony.…”

“…This special issue on tropical wetlands has 11 papers that went through the normal journal review process and are presented starting with a paper by Hribljan et al (2016) focusing on high elevation peatlands in Ecuador, followed by a paper that compares C stocks in tropical peatlands and mangroves in Mexico (Adame and Fry 2016), and then a series of 9 papers assessing mangrove dynamics from Africa Tang et al 2016;Trettin et al 2016), South and Latin America Kauffman et al 2016;McFadden et al 2016), and Southeast Asia MacKenzie et al 2016). The final paper is a global review on impacts of rising ocean water levels on mangrove ecosystems ).…”

Monitoring of Eco-Restoration of Mangrove Wetlands through Time Series Satellite Images: A Study on Krishna-Godavari Delta Region, East Coast of India

“…Mangroves are important coastal habitats for several ecological, economical, and protective functions (Biswas et al 2009;Cavanaugh et al 2014;Nortey et al 2016) and act as barriers against storm surges, floods and tsunamis (Alongi 2008;Kulkarni 2009;Teh et al 2009;Yanagisawa et al 2009;McFadden et al 2016). They have a highly efficient nutrient retention mechanism (Alongi 2002) and serve as breeding and nursery grounds for a wide range of aquatic and terrestrial species (Kumara et al 2010).…”