Bhakta Karki

Predicting the Uncertain Future of Tropical Forest species in a data Vacuum

Tropical regions are rich in biological flora and fauna. Many researches have been done in the field of tropical forest ecosystem. People are presenting their views on degrading situation of tropical forest based on their findings. However, no-one has come across or predict the exact realities, infact what is going on around tropical regions. Observing the increasing trend of human populations and their excessive pressure on forestry, it was predicted that humans in rural settings contribute most to deforestation of extant tropical forests and deforestation and habitat loss are expected to lead to an extinction crisis among tropical forest species. However, “Trends such as slowing population growth and intense urbanization give reason to hope that deforestation will slow, regeneration will accelerate, and mass extinction of tropical forest species will be avoided,” (S.J. Wright). Studies suggest that deforestation rates will decrease as population growth slows, and a much larger area will continue to be forested than previous. It is the truth that Tropical forests diminished during repeated Pleistocene glacial events in Africa and more recently in selected areas that supported large prehistoric human populations. Despite many caveats, the projections for forest cover provide hope that many tropical forest species will be able to survive the current wave of deforestation and human population growth. Consequently, it can be believed that creative strategies to preserve tropical biodiversity might include policies to improve conditions in tropical urban settings to encourage urbanization and preemptive conservation efforts in countries with large areas of extant forest and large projected rates of future human population growth. In addition that land-use history interacts with natural forces to influence the severity of disturbance events and the rate and nature of recovery processes in tropical forests. Although we are far from an integrated view of forest recovery processes, some generalizations can be made. Despite evidence of rapid forest recovery following large-scale deforestation, many degraded areas of today’s tropics will require human assistance to recover forest structure, species composition, and species interactions typical of mature tropical forests.

Similarly, it is complicated to predicate the relationships between rural and urban population growth and the scenario of deforestation. Even though, the general assumption produced for the ecological value that primary secondary and degraded forest can be treated as equally. Secondary forests play a crucial role in tropical forest landscapes providing a suitable habitat for many species and the necessary haven for species currently restricted to small patches of native habitat, there the role of degraded and secondary forest are pivotal. Contradictorily, naturally regenerating forests in the tropics depends on old growth forest and which has a high biological value. However, the existing studies provide an important service in identifying secondary forests as being more favorable for conservation than many other land-use options (e.g., agriculture, plantations), although the fact that they are often undervalued has frequently resulted in over-exploitation or conversion. So, the many more scientific papers were assessed to find out the role of secondary forest for the conservation of tropical forest species which have stated the importance of regenerating lands for tropical forest species. The evidences are not clear, shows a poor and weak sampling design, no inter-study comparison, and flaws in data analysis and interpretation which always create the differences or gap between primary and secondary forest for biodiversity conservation.

In focusing on the importance recovery and species richness that species composition recovers much more slowly, where mature-forest species can still be absent from secondary forests. If this pattern is generally true, then secondary forests will not provide a reliable and effective safety net for the many tropical forest species ,and areas of the world that are undergoing rapid loss of primary habitat will permanently lose many species. The value of secondary forests for the conservation of tropical forest species highlights the importance of an objective evaluation of the current status of our knowledge. Although the analysis indicates that species richness and composition exhibit limited recovery where the conclusions were made based on fewer unreplicated studies.

In the long-term degraded and the potential forest could attain a structure and species composition similar to primary forest if we protect from further disturbances. First most species have a small range sizes relative to the mean range size, increasing their probability of extinction by chance alone (Gatson1994) and second species with small ranges also tend to be scarce within those range (Brawon 1984), so the probability of extinction is increased on two counts. Most of these areas of co-occurrence of species with small range are disproportionately threatened by human activity (Cincotta et al.2000). Species are being extinct from biogeographically distinctive hotspots due to habitat loss. The main reason is secondary forest are highly heterogeneous, heavily degraded, isolated by hostile matrix habitat and poorly connected to regenerating forests where forest fires, alien species, pathogens and hunting further eroding the biodiversity value. Changing land use pattern causing heavy soil erosion and nutrient depletion may inhabit in natural regeneration due to abandoned after intensive agriculture.

Therefore, tropical forests are currently facing different kinds of threat from multiple factors including land-use change on a massive scale, habitat loss, wildfires, and hunting. So, the urgency is needed to know the conservation value of secondary forest. Secondary forests are more favorable for all the prospective like species coexistences to agriculture point of view. However, prediction about the conservation value of tropical forest secondary forests for most species still lacking a scientific data.

References:

S.J.Wright. 2006. The future of tropical forests. Smithsonian Tropical Research Institute and H.C. Muller-Landau, University of Minnesota, in Biotropica online.

Brawon, J. H. 1984. On the relationship between abundance and disturbance of species. The American Naturalist 124:255-297.

Cincotta, P.R., J. Wisnewski, and R. Engelman. 2000. Human population in the biodiversity hotspots. Nature 404:990-992.

Gatson, K.J. 1994. Rarity. Chapman and hall, London.