Ecological values of mangroves
Mangrove ecosystems represent natural capital capable of producing a wide range of goods and services for coastal environments and communities and society as a whole.
[6] Mangrove systems support a range of wildlife species including crocodiles, birds, tigers, deers, monkeys and honey bees.
[3] For instance, terrigenous sediments and nutrients carried by freshwater runoff are first filtered by coastal forests, then by mangrove wetlands, and finally by seagrass beds before reaching coral reefs.
[10] Mangroves supply nutrients to adjacent coral reef and seagrass communities, sustaining these habitats' primary production and general health.
As new cities are developed, mangrove forests around the world have felt a great impact not only on their ecosystems health, but also their wave-attenuating capacity.
[16] Mangroves provide a number of essentials for many different ecosystems, including food and shelter for a diverse animal community, living both below and above sea level.
Unless ecosystems have the space to adjust their location or elevation in the intertidal zone to the sea level rise, they will be stressed by changed inundation periods.
[19] It appears that as the sea-level is slowly rising, mangroves are a better alternative to protecting coastlines from eroding than other man made structures, such as seawalls.
The 2004 Indian Ocean earthquake and tsunami illustrated that healthy mangroves serve as a natural barrier against massive waves – protecting infrastructure developments and saving lives.
The World Conservation Union (IUCN) compared the death toll from two villages in Sri Lanka that were hit by the devastating tsunami giant waves.
From this global pattern it is expected that mangroves in New Zealand, near their southern geographical limit would have relatively low productivity compared to their tropical equivalents.
Many aspects of New Zealand mangrove systems have not yet been sufficiently studied; therefore their importance in relation to marine and estuarine species and their role in terms of ecosystem structure and function is inadequately understood.
The benthic invertebrate fauna of New Zealand's mangroves forests appear to be modest in both abundances and species diversity compared to other estuarine habitats.
At the international level, the common approach to major environmental policy issues has been to formulate conventions, treaties and agreements, which all concerned countries become signatories to.
[23] Of the approximately 100 countries that have mangrove vegetation, around 20 have undertaken rehabilitation initiatives,[24] establishing nurseries and attempting afforestation and re-planting in degraded areas.
Sectoral management has inevitably resulted in prejudices regarding their objectives, leading to conflicts of interest, to unsustainable resource use, and to poor and less powerful groups becoming more disadvantaged and disenfranchised.
[30] However, the true economic value of mangrove diversity and natural resources is difficult to measure and important ecological processes and functions undervalued.
Research has established that, regardless of which approach is decided upon, sustainable management can only be achieved if evaluation of mangrove areas is undertaken on a site-by-site basis.
