Recently the tropical forest of the scattering islands realm of Oceania has experienced declining and devastating on biodiversity and ecological communities, as the impact of exotic plants and animals as well as the activities of humans around the area. In the Biological Conservation, the article “Biodiversity conservation in tropical forest landscapes of Oceania” (8 February 2010) written by J.C.Z. Woinarski gives some research and examples of the tropical forest conservation. Woinarski takes a close look at the conservation issues about the tropical forests of Oceania, which now is a significant problem not just of the regional ecosystem but also of the world’s biodiversity.
There are few reasons that why we should stress this problem of this specific area. The Oceania areas are included the Pacific island regions of Polynesia, Micronesia and Melanesia, tropical Australia (77%) and New Zealand. There is relative small numbers displaying when we compare the Oceania’s properties in terms of the land area (660,000 km2) and the human population (just over 13 million, <0.2% of the earth’s total) with a global scaling. Other than that the tropical forests of Oceania and their degree of biodiversity are significant worldly because of the high level of its localized endemic species and those species contribute significantly to the biodiversity of world’s tropical forest, which is also the reason why Woinarski select this particular region to investigation. However, currently these tropical forests in Oceania are exposed in a shortage of conservation reserves, for example in some countries the conservation is nearly nominal and the resources are still exposed in the abusive usage and degradation. One of the major reasons of the existence of this situation in part is the demands on the economic development and the poor governance.
As the result of many associated factors of some indirect threats of the entire ecosystem of Oceania, it is pointless to demonstrate the consequences of those threats or try to find out the root-causes of them in Woinatski’s opinion. Nevertheless there are still some direct warnings faced by the tropical landscape of this area which we have to give elaborate examination. Besides it has never been difficult to illustrate numerous cases from few observations of recent studies. At first, the introduction of non-native species leads to the catastrophic impact of many native species on the Oceania islands. Since the limited genetic diversity, small population sizes, and low reproduction ability of the island biota, this kind of characteristic can impair the defense against novel disease consumers and predators. The example of Hawaii is typical to illustrated, 73-93 bird species has extinct after the Polynesians arriving and a further 17 have gradually disappeared as well by the recent times, and the remaining species are mostly trapping in the possibility of extinction. Furthermore there are only 1000 and 1500 native species of flowering plants on the Hawaii islands, however, at least 800 out of over 4000 introduced species has become invasive non-native species to the localization.
At the same time the climate change also can contributes to profound compression or shrink of the islands of Oceania. Let’s say only 1m of sea level arisen can lead to sharply contract or disappear of island’s surface. Then the statics done by other researchers at 2005 have shown the 1℃ rising temperature will emerge the extinction of one of the 85 species of the upland area, similarly 3.4℃ leads to 30 species dying out, and 4.8℃ makes for 60 species extinct. There are also natural and historical disturbances triggered the deforestation and devastation of Oceania tropical forestry. Even some regions have undergone a long period of history have been exposed in direct human modification, like slash-and-burn agriculture or even the abandon to natural regeneration. Also if we include the disturbance of resource exploitation and land usage and hunting, it is no surprise that the Oceania tropical forests will get to this desperate point.
Now we stand on the point where facing with this bleak outlook of the tropical forest of Oceania. Woinarski illustrated few responses as well to try to clarify this situation. Comparing with most Oceania’s forests, the vast tropical forests of Australia is an exception due to its strategic restoration and organized protection and management of the resting forest areas. The point which cannot be overlooked is some inconsistent results between the studies of Woinatski’s and that of Bowen et al. (2007). The later one reported that some species shows increases with having highest richness and successional age, especially those species that rare in cleared areas and secondary forest. Whereas, restoration of the Oceania region now is obviously constrained by the downwards growth of special native species. Namely the risk of flying-foxes is a good example to take into consideration (Cox et al., 1991). Hence, to some degree, this might implicate that the ecosystem of some individual islands may nerve be reobtained.
At the end we have to take the social factors and the validity of governance into account. Since the conservation of forests is associated with large range of international trade policies and market and demand. Therefore the improvement of international policy has become a spotlight topic. What’s more this revolution of policy has to be specific, realistic and implementable.
Reference:
Woinarski, J.C.Z., 2010. Biodiversity conservation in tropical forest landscapes of Oceania. Biological Conservation, 143: 2385-2394
http://journals1.scholarsportal.info/details-sfx.xqy?uri=/00063207/v143i0010/2385_bcitfloo.xml
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