Mangroves enhance the biomass of coral reef fish communities in the Caribbean

Mangrove forests are one of the world's most threatened tropical ecosystems with global loss exceeding 35% (ref. 1). Juvenile coral reef fish often inhabit mangroves, but the importance of these nurseries to reef fish population dynamics has not been quantified. Indeed, mangroves might be expected to have negligible influence on reef fish communities: juvenile fish can inhabit alternative habitats and fish populations may be regulated by other limiting factors such as larval supply or fishing. Here we show that mangroves are unexpectedly important, serving as an intermediate nursery habitat that may increase the survivorship of young fish. Mangroves in the Caribbean strongly influence the community structure of fish on neighbouring coral reefs. In addition, the biomass of several commercially important species is more than doubled when adult habitat is connected to mangroves. The largest herbivorous fish in the Atlantic, Scarus guacamaia, has a functional dependency on mangroves and has suffered local extinction after mangrove removal. Current rates of mangrove deforestation are likely to have severe deleterious consequences for the ecosystem function, fisheries productivity and resilience of reefs. Conservation efforts should protect connected corridors of mangroves, seagrass beds and coral reefs

Friends or Foes? The Problem of South Florida’s Invasive Mangroves

A recent global review on the impacts of climate change on mangroves concluded that different regions will experience varying degrees of impacts due to the variability of expected changes in climate (shifts in precipitation, frequency and intensity of storms, droughts, sea level rise, change of ocean currents, increases in CO2 concentrations, etc.) and the variety of types and mangrove assemblages growing in these regions, including different species composition of mangrove forests. In North America and the Caribbean, these changes are dependent upon a predicted higher frequency (and intensity) of tropical storms, sea level rise, changes in patterns of precipitation, and higher temperatures. Located at the land-sea interface, mangroves in this region are expected to expand their ranges poleward (towards North Florida), or migrate into other coastal ecosystems (e.g., the Everglades), provided no natural or urban center barriers are present to prevent this expansion. If rains increase, as is anticipated, along the United States-Mexico border, mangroves may likely begin to thrive in places currently occupied by unvegetated salt flats. However, a lack of rain may also be of benefit in areas such as Louisiana where marsh diebacks have been linked to droughts, which directly increases the likelihood of mangrove migrations into these ecosystems. Given the services that mangroves provide and the legal protections that mangroves receive, it is shocking to discover that their future existence may be compromised or threatened. Certainly, the greatest threats to mangroves in Florida are from direct and indirect human impacts of development, including pollution and habitat destruction. Mangroves may also be naturally damaged and destroyed from disturbance events such as tropical storms and hurricanes. However, a new threat to native mangroves has recently emerged: the introduction of invasive mangrove species. These non-native species may threaten the ecosystem dynamics of mangrove forests and may alter the natural coastal landscape of South Florida unless eradicated

STATUS OF MANGROVES IN SRI LANKA

In Sri Lanka many estuaries and lagoons are fringed with vastly diverse mangrove forests. The total mangrove cover is very small as 0.1 to 0.2 percent of the total land area. The distribution of fauna and flora varies along with wet and dry zone in the country. Around 25 species of flora are exclusive to mangroves and more than 25 species can be identified as associated mangroves. Variety of invertebrates and vertebrates are conspicuous in the mangrove forests, but only a few species are confined to the ecosystem. Heavy utilization and reforestation for shrimp farms and building construction work severely affect on this ecosystem. When compare to decline rate of mangrove forests in Sri Lanka, current implemented conservation measures are inadequate

Connectivity between coastal habitats of two oceanic Caribbean islands as inferred from ontogenetic shifts by coral reef fishes

Mangroves and seagrass beds are considered important nursery habitats for juveniles of coral reef fishes. Studies have mostly focused on the fish community of just one habitat, so the connectivity between different coastal habitats is often unclear. In this study, density and size of reef fish were determined using a single sampling technique in four non-estuarine bay habitats and four reef zones in Curaçao and Bonaire (Netherlands Antilles). The data indicate that of the complete reef fish community at least 21 species show ontogenetic crossshelf shifts in habitat utilization. The 21 species mainly utilized shallow-water habitats (mangroves, seagrass beds, channel and shallow reef) as nursery habitats and the deeper coral reef zones (\u3e 5 m depth) as adult lifestage habitats. Fish species utilized 1–3 different nursery habitats simultaneously, but habitat utilization clearly differed between species. Previous studies showed that the dependence on these nursery habitats is very high, based on reduced density or absence of adults on coral reefs where these habitats were absent. The strong connectivity between several coastal habitats during the ontogeny of various commercially important reef fish species is evidence for the inclusion of bay habitats within boundaries of fishery reserves or marine protected areas

Mangroves v1.0: a new taxonomic tool to characterize mangroves. The case of South east Indian and Sri Lankan mangroves and potential application to African mangroves

In this paper we present an innovative tool for plant identification conceived to reinforce the national capacity building in taxonomy. We introduce Mangroves v1.0, built up on a species identification system called IDAO (Identification Assistée par Ordinateur). This software allows the identification of 50 mangroves species of South East India and Sri Lanka, with the perspective to adjust and extend to other of the world. This software provides and facilitates dissemination of scientific and traditional knowledge. Corollary, it appears as a good support to training, research and development actions and its applications, from awareness to practical management of trees and the ecosystem, could benefit African mangroves and contribute to their renewed interest. (Résumé d'auteur

Grenada Carriacou Petite Martinique

The Eastern Caribbean Seascape is an arc of islands linked through diverse coral reef ecosystems, oceanic currents, migratory pathways and a rich cultural heritage. The Eastern Caribbean Coral Reef Report Cards are a series of individual reports for the6 participating countries and provide an easy-to-understand summary of the state of the region's marine resources. The Report Cards collate data from 277 comparable coral reef surveys and map in detail 383 km2 of coral reefs, 19 km2 of mangrove, 286 km2 of seagrass, 44 designated and 50 proposed Marine Managed Areas (MMA). The Report Cards provide an initial baseline on the current state of the reef and identify gaps. Reporting this type of information will help track progress in protecting reefs and inform future monitoring and management. The vision is to produce report cards every 2 years and share data through the CaribNode regional spatial data platform. Future report cards will include key socioeconomic and management effectiveness information. Each Report Card includes information on:Key Habitats (location and extent of coral, mangrove, seagrass)Reef Health Index (a measure of the health of four key coral reef indicators)Marine Managed Areas (size and location of designated and proposed areas

Climate-driven regime shifts in a mangrove-salt marsh ecotone over the past 250 years.

Climate change is driving the tropicalization of temperate ecosystems by shifting the range edges of numerous species poleward. Over the past few decades, mangroves have rapidly displaced salt marshes near multiple poleward mangrove range limits, including in northeast Florida. It is uncertain whether such mangrove expansions are due to anthropogenic climate change or natural climate variability. We combined historical accounts from books, personal journals, scientific articles, logbooks, photographs, and maps with climate data to show that the current ecotone between mangroves and salt marshes in northeast Florida has shifted between mangrove and salt marsh dominance at least 6 times between the late 1700s and 2017 due to decadal-scale fluctuations in the frequency and intensity of extreme cold events. Model projections of daily minimum temperature from 2000 through 2100 indicate an increase in annual minimum temperature by 0.5 °C/decade. Thus, although recent mangrove range expansion should indeed be placed into a broader historical context of an oscillating system, climate projections suggest that the recent trend may represent a more permanent regime shift due to the effects of climate change