Implications of Land-Cover Changes and Fragmentation For Biodiversity Conservation

by Maithili Joshi

Deforestation can have substantial impacts on the vast biodiversity within tropical rainforests. In Hainan, China, importance is placed on trying to protect the habitat and biodiversity in the natural forests, specifically in the Changhua watershed. The Changhua watershed is an important area for China because it has been identified as the “center of endemism for plants and birds”, so conserving this area is particularly important for maintaining biodiversity. In the last few years, biodiversity has been threatened by new rubber and pulp plantations causing forest fragmentation and larger patch distances. In this study, Zhai et al. (2014) looked at the implications of deforestation on biodiversity, especially of endemic species and the ecosystems surrounding using land cover data.

Trying directly to quantify biodiversity in a landscape turned out to be hard, and furthermore difficult to interpret both land-cover data and fragmentation. The scientists analyzed land-cover satellite images for the years 1988, 1995, and 2005 and then compared natural forests and plantations in the Changhua watershed area. They used six types of land cover, including: natural forests, natural shrubs and grasslands, tropical crops, rubber plantations, pulp plantations, and open areas. In the years 1988 −1995, natural forests had increased in area, and only natural shrubs and grasslands decreased. Only a small number of natural forests were converted into other land covers. In the next decade, there was a drastic change natural forests, shrubs, and grasslands land cover, while pulp plantations and rubber plantations showed the highest increase. Overall fragmentation continued to increase, while habitat quality decreased. At the same time, there was an increase of fragmentation. All these results lead to the conclusion that that during the most recent time period of the study, 2005, land-cover changes resulted in loss, isolation, and fragmentation of protected areas. The implications of this fragmentation and isolation are substantial. First, it will decrease genetic diversity in flora and fauna, and affect the survival and reproduction of many endemic and endangered species. There will also be changes in community structure, composition, and species richness. With the beginning of agro-forestry there are implications that the disturbance to many of the natural forests will lead to invasive species that are detrimental to the survival of native species. The displacement of natural ecosystems caused a negative effect on the local biodiversity, meaning that these plantations will have an impact on the endemic species that are so important to the Changhua watershed. Further, there are several implications on biodiversity conservation as a result of forest fragmentation. The small fragments were not adequately able to support enough species, especially endemic species. Moreover, patch numbers, which are an ecological effect of fragmentation, increased, causing longer distances between patches, hurting genetic diversity because of the habitat isolation. This barrier is a concern to biodiversity conservation because of certain species, especially plants, that are used in order to track climate change. Without these species, it will be increasingly difficult to monitor changes. Structural damage to vegetation is another important factor in this discussion because it disrupts to the forest floor, soil layers, nutrient cycling, and decomposition, completely altering the composition of the natural forests, making it difficult for the original species to re-grow in these areas. Habitat fragmentation, loss, and isolation have detrimental effects on endemic species. If the problem is not effectively approached, extinction may occur. In an effort to control the issue at hand, restoration projects will be important in maintaining biodiversity. It is especially crucial to protect natural forests in areas with high biodiversity as a priority. It is also crucial to stop all current activity in converting forests for plantations with strictly enforced policies and the establishment of “environmental friendly corridors” in order to maintain connectivity, limiting the impact of fragmentation and isolation.

Zhai, DL., Cannon, C., Dai, ZC., Zhang, CP., Xu, JC (2014) Deforestation and fragmentation of natural forests in the upper Changhua watershed, Hainan, China: implications for biodiversity conservation. DOI 10.1007/s10661-014-4137-3

http://www.ncbi.nlm.nih.gov/pubmed/25416130

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