Climate change & wildlife: How focused monitoring of distribution, population trends can help conservation efforts

Two recent studies highlighted the need for monitoring wildlife — their abundance and distribution as well as assessing their conservation threats — due to climate change, among other factors. First was the State of India’s Birds Report 2023 that identified rapid decline of many bird species and increase of some. 

The second was a study published in the journal Nature on the rapid decline of amphibians and pushing many species into the threatened status, which in future could face a high risk of extinction.

Both studies pointed to the possible impacts of climate change and merit further investigation as birds and amphibians are important indicators of health of an ecosystem. Species distribution modelling under current and future climate change scenarios can help in conservation decision-making.

Species distribution modelling in ecological studies started over a 100 years ago but the major advancement began with the BIOCLIM model starting 1984. The model incorporated the monthly mean maximum and minimum temperature and precipitation. It was mainly used to identify how different species were distributed in different climatic zones.

BIOCLIM was an advancement of the Hutchinson bioclimate classification developed by Sir John Hutchinson, a British ecologist who made significant contributions to the understanding of the relationships between climate and the distribution of plant and animal species.

In 1991, with the advancement of Geographic Information System, the use of spatial data to study species distribution became popular. The most recent advancement in species distribution modelling was the MaxEnt Maximum Entropy model that uses species occurrence data. This includes the geographic locations where a species has been observed and environmental data like temperature, precipitation, elevation and land cover. 

The output of MaxEnt is a map of the potential distribution of the species or probability of occurrence across the area. A few such studies using MaxEnt have been conducted in India — one is the study on Hoolock Gibbon in the upper Brahmaputra valley of northeast India using 19 different environmental parameters and identified priority conservation areas for the Hoolock Gibbon, the only ape species found in India. 

Such priority conservation areas can be included as protected areas, if they were not already, or tend to additional care like removing anthropogenic pressure of grazing and logging and to management actions like fire protection and removal of invasive species, among others. 

One of the major constraints for ecologists in India to use species distribution modelling and inform conservation decision-making is the data limitation both on species occurrence and environmental parameters like forest cover. 

In the case of the State of India’s Birds Report 2023, contributions by professional ornithologists and amateur bird watchers and citizens made this robust data collection possible, which for example in the case of peafowl helped to know their range extension into areas where they were previously absent. 

In the case of the study in Nature, the amphibian data came from the International Union for Conservation of Nature Red List of Threatened Species, which is compiled from scientific literature, field surveys and expert assessments. 

However, for numerous endangered species of birds, reptiles, butterflies and primates, the species occurrence data is not available in the public domain, although surveys were conducted by agencies like the Zoological Survey of India. Similarly, environmental data like tree cover, which the Forest Survey of India collects every two years, is not available in the public domain. 

In absence of such data, it is hard for researchers to examine the ecosystem changes like grassland to shrubland or increase of vegetation in alpine meadows or forests becoming drier that has led to range expansion of species like peafowl or decline of others. 

Field work is essential to train species distribution models and validate the results. In 2006, a group of eminent researchers wrote in Current Science, how denied access to forests and wildlife reserves affect ecological research in India and over the years there hasn’t been any major change in facilitating field research by the state governments or democratisation of data that the national government and its associated institutes collects.

India is one of the major global biodiversity hotspots and monitoring species distribution including in the context of climate change is essential and requires collaboration of government and private researchers along with data democratisation. This will collectively benefit India’s biodiversity conservation goals. 

Dhanapal has worked on the preparation and implementation of SAPCC with state governments, and with multilateral and bilateral agencies. He is an independent consultant on climate change and environment. 

Views expressed are the author’s own and don’t necessarily reflect those of Down To Earth.

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