Land-Use Change and Biodiversity

As growing human populations place additional burdens on land due to increased needs for food, energy, natural resources, economic development, and space, pressure increases to convert natural habitats for other uses. Right now, thirty-seven percent of Earth’s landmass, excluding Antarctica, is already used for food production. With a projected global population of 9.8 billion people by 2050, land utilized for agriculture is expected to increase. These land-use changes are one of the gravest threats to remaining biologically diverse habitats and the organisms that make up these ecosystems. Conservation efforts are critical for protecting biodiversity as well as for natural solutions to mitigate greenhouse gas emissions, such as planting more trees and keeping the carbon-rich soils and forests that currently store carbon intact. 

Effects of Forest Loss on Bird Populations

The degradation and conversion of forests to alternative land uses, such as agriculture, is one of the leading causes of biodiversity loss, especially in the tropics. The impacts of land-use change are likely to be exacerbated by the looming climate crisis. 

Our researchers are investigating how forest loss affects increasingly threatened species in the Indian Himalayas. The Himalayan mountain range faces ever-growing forest loss and is also warming three times as fast as the global average. One of the most pressing issues in predicting the impacts of land-use change on biodiversity is understanding how species’ adaptation to their climatic environment (in other words, their thermal sensitivities) influences how they fare in human-modified habitats, which are typically warmer and more temperature variable than forests.

C-PREE researchers are involved in two main projects in the Himalayan mountain range, taking advantage of the stark differences in annual temperature variability at the two ends of the Himalayas. These are: (a) how does adaptation to varying degrees of seasonality influence whether species continue to inhabit agricultural landscapes, and (b) how do interactions between land-use change and climate change affect Himalayan bird populations.

Researcher: Umesh Srinivasan

Related Publication: "Annual temperature variation influences the vulnerability of montane bird communities to land‐use change" - Read more in C-PREE News or access from Ecography

Understanding and Minimizing Biodiversity Loss from Agricultural Expansion

To date, the single greatest cause of species endangerment has been habitat loss, primarily driven by agricultural expansion. Agriculture already occurs over approximately 40% of the world’s ice-free land, and most projections predict that agriculture will expand and intensify in order to meet rising demands from a larger, wealthier global population. Where and how this expansion takes place will have serious implications for the future of biodiversity, making land-use planning a critical component to achieving agricultural sustainability, particularly in Sub-Saharan Africa, where food demand is expected to grow significantly. However, major variation exists in how biodiversity metrics are incorporated into land-use planning models, with the potential to produce wide variation in recommended outcomes.

Building on a land-use prioritization model designed to help plan future agricultural expansion in Zambia while minimizing costs to biodiversity and carbon stores, our researchers are exploring how land-use recommendations change depending on the underlying biodiversity metrics used, the methods used to combine data, and the scale at which the analyses are conducted. This research will help illuminate the consequences of often overlooked methodological choices, and ultimately provide recommendations for both producers and consumers of conservation prioritization analyses.

Researcher: Chris Crawford

What Can Pikas Tell Us about the Effects of Climate and Land-Use Change on Species?

Climate change and land-use change are among the greatest threats to biodiversity; their effects differ depending on the region and the time period. Species' vulnerability to environmental changes depends on many factors, such as their physiological capacity, their ability to move or disperse into new areas, and the size/range of the current area over which they are distributed. How climate and land-use changes interactively threaten species' ability to persist through time and space has not been well studied to date.

Pikas - small mountain-dwelling mammals in Asia and North America - may help us to better understand how species are being affected by climate change and land-use decisions. There are at least 30 species of pikas, including two dozen in China alone, and they vary in distribution range, population size and preferred habitat. Because of this variability, they provide a suitable study for addressing the above questions.

Using correlative models (including spatial analysis), we are investigating how climate change and land-use change will reshape the distribution of pikas in China, and whether climatic and land-use variables are interactive synergistically or antagonistically. By collecting data on the life histories of different pika species as well as on their environments, we can develop mechanistic models to predict their vulnerability in the context of climate change and land-use change.

Researcher: Liang Ma