A Matter of Survival: Pacific Islands Vital Biodiversity, Agricultural Biodiversity and Ethno-Biodiversity Heritage
Thaman, R. R., Pacific Ecologist
Biodiversity is the foundation for survival and sustainable development on pacific Islands, with a high proportion of pacific Islanders livelihoods coming from natural resources, writes PROFESSOR R. THAMAN. But urbanisation and western development, deforestation, forest degradation, and loss of agrobiodiversity are proceeding at frightening rates, along with erosion of pacific Islands' sophisticated knowledge systems. Yet there's great potential to reverse these trends. For food security and cultural and economic survival, the highest priority must be placed on preserving the ethno-biodiversity, agroforestry and agrobiodiversity models of pacific Islands. This will require education and re-education to foster the understanding of existing trees, agroforestry systems and ethnobiodiversity before the knowledge dies out. The tools are in the trees and the dynamic existing traditional systems that have sustained pacific Islanders over thousands of years. (part two of a two-part article.)
Vital coastal and mangrove biodiversity
An analysis of the ecological and cultural importance of 140 coastal and mangrove species in Pacific agroforestry systems showed these coastal plant communities had many uses. The area of this study reached from New Guinea and New Caledonia in the west to the smallest atolls of Easter Island and the Hawaiian islands in the east. (1) The most important ecological functions of these plant resources, include: providing shade, as animal and plant habitats; protection from wind, erosion, flood and saltwater incursion; land stabilisation, protection from desiccating effects of salt spray, soil improvement and mulching; and as animal food or links in important terrestrial and marine food chains.
Mangrove ecosystems have particular importance, contributing either directly or indirectly, through primary and secondary productivity, to the nutritional requirements of many marine food species. (2) Research in Fiji has shown over 60% of commercially important species live in mangroves or depend on mangrove food webs at some stage in their life cycle. (3) More rigorous research gives figures of 67% and 80% for eastern Australia and Florida. (2) Destruction and reclamation of mangroves have deleterious effects on fisheries yield.
Similarly, Pisonia grandis is the most important seabird rookery species throughout the atoll Pacific, providing phosphate-rich, bird-guano which is very important for pig feed in many parts of the Pacific. Where Pisonia has been removed, often to be replaced by coconut plantations, seabird populations decline and the location of schools of tuna based on the presence of seabird flocks becomes problematic for fishermen.
One of the most important ecological roles of coastal plants is in the protection they give inland agricultural areas, non-coastal vegetation and fauna, settlements, and water supplies from saltwater spray and storm surge. Plants with very high tolerance to salt spray and saltwater incursion are particularly valuable. Farmers throughout the Pacific purposely leave strand or mangrove forests intact on the seaside of their gardens, knowing removal of these trees makes farming difficult.
Imprudent commercial agricultural expansion in Tonga into the coastal zone where trees were removed on the windward coast of Tongatapu, the main island, to make boxes for shipping bananas to New Zealand, made agricultural production difficult in inland areas. Later, a successful coastal reforestation program begun in 1993 by the local community, in collaboration with the Forestry Department, planted 20,000 trees with over 20 native coastal species along the 2 km of coastline. The lesson learned was that reforestation is possible, but it's far easier to protect than to recreate the multi-species diversity and community structure created by God or generations of traditional agroforesters! (4)
Cultural-use analysis shows there are 75 different purpose/use categories for coastal plants, and 1,024 frequency uses for 140 plants, an average of 7. …