~ by Archita Sharma
Two conservation priority landscapes in India - the Western Ghats and Central India remain major strongholds for several endemic and threatened species. However, urbanization and land conversion have resulted in wide-scale habitat fragmentation in both the landscapes. Fragmentation can alter how animals move across a landscape.
Wide-ranging mammals are particularly affected because they travel long distances to forage, breed, and find new territories. Identifying where and how have the mammalian movements been impacted at large regional scales will be critical in ensuring habitat connectivity and preventing local extinctions.
A new study published in Biological Conservation evaluated landscape-wide permeability to the movement of five endangered and vulnerable mammals - Asian Elephant, Gaur, Leopard, Sambar, and Sloth Bear in these two priority landscapes. The expansive study area covered 120,000 km2 of the Western Ghats and 729,000 km2 of the Central Indian region. For each of the five study species, the researchers modelled movement in the presence and absence of landscape features such as land-use land-cover, infrastructure and human population. They generated spatially explicit maps identifying areas where animal movement is impeded, reduced, unrestricted, increased, and channeled. These categories can be interpreted as follows – movement is impeded and reduced due to underlying high resistance landscape features, unrestricted due to underlying low resistance areas, finally increased and channeled due to high resistance surrounding landscape features.
~ 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
~ by Archita Sharma (WWF-India)
The Central Indian Landscape has been a stronghold for several long-ranging wild mammals for several thousands of years. Its dense forests and rolling grasslands provide a rich holdout for tigers and several other carnivores, big and small, prowling, hunting, and stalking in the shadows of this wild heartland. But over the last century, Central India has lost a share of its forests to growing human settlements, railways, roads and rampant mining. So, a landscape that was once a contiguous expanse of dry deciduous forests is now fragmented, remaining with 34% forest cover, out of which only 8.5% is legally protected.
Long-ranging mammals need room to roam. In many mammalian carnivores, the juveniles move out of their mother's territory to establish their own, with the males moving long distances to find new territories. When their dispersal routes to seek out prey, territory and mates are severed by roads, cities, villages, mining, and railways, natural populations can be isolated into small island populations. These small isolated populations face a higher risk of disease and extinction. Population genetic structure can help us determine the isolation or connectivity in natural populations.
To put it simply, genetic structure captures the level of genetic variation existing in a population. If mammals from different forest patches are mating with each other, they will be genetically more similar and will consequently have a lower genetic structure. Similarly, isolated populations will be genetically more distinct and will have higher genetic structure. Using DNA as a tool, estimating structure and connectivity in mammals can help us understand fine scale impacts of fragmentation. While there are several such studies on tigers, very little is known about how fragmentation impacts other mammalian species.
A new study published in Diversity and Distribution answers how the same level of habitat fragmentation has differential impacts multiple mammalian species in the threatened Central Indian Landscape. Researchers from the National Centre for Biological Sciences (NCBS), Bengaluru, investigated the genetic structure and connectivity in four long-ranging mammalian species — jungle cat, leopard, sloth bear, and tiger. The four species have varying body size, diet and dispersal abilities, and are expected to have species-specific responses to fragmentation. The two major objectives of the study were (1) to understand how the genetic structure is partitioned between these four species and (2) to find out how different landscape features like roads, built-up areas, and human density impact connectivity and dispersal in the study species.
~ by Amrita Neelakantan (NCCI Coordinator)
A timely study by NCCI founder Prof. Ruth DeFries and collaborators lays out possible scenarios for minimizing risk of exposure to COVID-19 in rural India as the lockdown is relaxed and migrants return to their villages.
What we know
Seasonal migration is a widespread livelihood option for households in forest-fringe areas of Central India, moving people from villages to the country’s cities for up to 6 months in a year. Typically, these migrants are young males and they return to the village in time to plant monsoon crops. Seasonal migrants are generally poorer and less educated than those that migrate permanently (for work or education) . In the current pandemic of COVID-19, the risks of exposing rural India with returning migrants from cities is of major concern for both rural communities and government authorities, as well as for migrants who are desperate to return with no source of income during India’s lockdown.
Moreover, communities on the periphery of forest areas in the country are some of the most vulnerable and poorest. Central India, one of the main forested areas in the country, is important for tiger conservation and has a high proportion of Scheduled Tribe populations. In these villages of Central India, the poorest households use seasonal migration to supplement their incomes , increasing the risks of exposure to COVID-19 as migrants return. These villages are even more at risk as they have poor or non-existent health facilities and low quality diets in typically crowded households . Additionally, most households continue to use fuelwood with high indoor air pollution already causing respiratory problems . While the populations are not as dense as in cities, the spread from village to village and lack of medical facilities is a grave concern.
As of this writing, the country has been in lockdown since March 24th. Seasonal migrants are unable to access work or means to return home. News channels have documented migrants returning home on foot. Quarantine facilities have been set-up in villages but the quality and efficacy of these are unknown. The government restricted inter-state travel for migrants after April 20th. As restrictions ease, chances persist of exposure and spread to adjacent villages from migrants who have already returned.
Given the economic hardships of lockdown, the authors of this study provide some alternatives to severe physical distancing. The objective is to reduce chances of exposure while allowing people to obtain essential supplies, plant crops, and carry out other necessities of daily life. A post-COVID-19 path could be informed by their results.
The study uses data from a 2018 study that surveyed approximately 5000 households in 500 forest-fringe villages in Central India. The original study was to assess patterns of migration over the previous five years (2013 – 2018) and was unrelated to tracking disease spread.
What they found
The researchers found that seasonal migration is widely dispersed across forest-fringe villages of Central India. Eighteen percent of surveyed households sent migrant workers to cities in the last five years. Seventy-five percent of villages had a least one household with migrants, and all districts had a least one village with migrants. Similarly, migrants traveled to 124 locations over the last five years. Over eight percent of migrants went to cities were COVID-19 cases were reported at the beginning of the lockdown, based on the publicly-available COVID-19 tracker site (www.covid19india.org).
The researchers used a simple, epidemiological model of disease spread to examine different scenarios of movement between and within villages (Figure 2). Using varying R0 values (the basic reproduction number that represents the expected number of cases generated by an infected individual), the researchers allowed for scenarios with lenient (no restriction R0=3), moderate (some restriction to interactions R0=2) and maximal (highest restriction R0=1) movement within and between villages. The findings highlight how different strategies for easing lockdown restrictions might vary in terms of the number of people exposed in the unlikely but possible event of the virus reaching a village.
The most effective way to limit exposure is obviously to keep everyone within and across villages in lockdown. But as most Indians are now familiar with, keeping an indefinite lockdown is not feasible with many states already easing some restrictions to save India from economic hardship. The more important question then becomes, how one would begin opening up the lockdown or easing restrictions to balance the economic needs with necessary caution to avoid exposure to the virus.
This study reports, for a hypothetical case of exposure in one village, that maximal limitations to movement between villages with lenient movement within villages (middle scenario in Figure 2) exposes fewer people than moderate restrictions that apply to both within and across villages (bottom scenario).
Incidentally, the scenario that led to the least number of exposed people in the model is similar to New Zealand’s successful “social bubble” and communities’ efforts in India to restrict entry to villages.
~ by Prameek Kannan (WWF-India)
The rusty-spotted cat is endemic to the Indian subcontinent; found in India, Nepal and Sri Lanka. Little is known about the ecology of this smallest of the world’s felids, and this combined with it’s rarity have warranted it being listed under ‘Schedule I,’ of the Wildlife Protection Act of India (1972). This is the same category of protection as the tiger and Asian elephant, which means that hunting or trading in it’s body parts can result in up to 7 years of incarceration for the guilty.
Until recently, it was considered as ‘Vulnerable,’ by the IUCN, but an increase in it’s occurrence records in different habitats in India and Nepal has seen it down-listed to ‘Near Threatened.’ However, even the most basic aspects of its biology, such as its habitat requirements, home range characteristics and diet remain unknown; these are crucial for conservation planning. A recent study provides a broad understanding of this species’ habitat preferences.
Kanha Tiger Reserve (KTR) in the central Indian highlands is the site for this study. The reserve harbors a mosaic of vegetation types, including; meadows and woodlands in the valleys (dominated by Sal Shorea robusta), hilly tracts of dense mixed deciduous forests and hilly plateaus with extensive grasslands. It also contains numerous perennial streams and ponds that support swamp vegetation. Kanha is a heaven for a whole suite of globally threatened species such as the endangered tiger and dhole, and vulnerable leopard, gaur, sambar, four-horned antelope and endemic hard ground barasingha deer.
Project Spotlight highlights our members' work in Central India.
|Network for Conserving Central India||