Increased patchiness of forests as infrastructure construction rises in India

~ by Kalyanee Paranjape

As one of the fastest growing economies in the world, India’s topography is undergoing rapid changes. Due to this expansion, ecosystems are under threat due to rapid land use changes and fragmentation. This has led to a growing interest in integrating conservation concerns in infrastructure development in India and an urgent need to illustrate the extent of their fragmentation.

A recent paper titled, “Bits and pieces: Forest fragmentation by linear intrusions in India”, aims to understand the impact of infrastructure developments on forest structural connectivity in India through analyzing forest patch characteristics. The authors have utilized patch size, amount of perforation and inter-patch distance to quantify clusters and fragmentation categories. Cluster analysis was used to identify large, intact patches that need to be preserved in future development action plans. And results were summarized at the national scale and for the existing protected area (PA) network. The results also cover two important conservation landscapes; the Western Ghats and Central India, which are rich in biodiversity and critical for survival of several threatened large mammals including tiger and Asian elephant.

The scientists found an increase in the number of forest patches and a reduction in the number of large patches due to linear infrastructure in India. High tension power-transmission lines and major roads were the most common linear intrusions within forests, and 70 % of the assessed protected areas had some amount of linear infrastructure passing through them. They also discovered that the highest fragmentation due to linear intrusions was observed in Central India, where an intact forest habitat of size 162,000 km2 was split into 5200 smaller patches with a mean patch size of 30 km2 and the largest patch being 16,850 km2 in size.

The authors recommend that infrastructure projects should not be established through the existing forests and when inevitable, proper mitigation strategies are vital to maintain connectivity. A more rational development plan would be to connect larger numbers of villages or people while safeguarding forests rather than to establish the shortest routes that would destroy forests, biodiversity, and ecosystem services. The study addresses the issue of fragmentation within forests and develops techniques that can be usefully applied to mitigate fragmentation problems in other fragile ecosystems such as tropical grasslands and savannas.

Spatial distribution of forest patches and their size: (a) Depicts the patch size distribution as influenced by infrastructure; (b) Depicts patch size distribution in absence of infrastructure intrusion.

Original Paper: Nayak, R., Karanth, K. K., Dutta, T., Defries, R., Karanth, K. U., & Vaidyanathan, S. (2020). Bits and pieces: Forest fragmentation by linear intrusions in India. Land Use Policy, (September 2018), 104619. https://doi.org/10.1016/j.landusepol.2020.104619