I’m a Bat Biologist

Many people are not aware that the most endangered terrestrial region of the planet is Southeast Asia, from China’s southwest to the Malaysian and Indonesian archipelagos. While global discussion of habitat loss and deforestation still tends to focus on the Amazon, the highest annual rates of deforestation in the world are in Southeast Asia, with agriculture, dam building, mining and other human activities synonymous with economic development now threatening most regional ecosystems.

One of these threatened ecosystems are limestone karsts: jagged, impressive formations that cover more than 800,000 sq km of Southeast Asia, each one home to unique species. Even individual limestone hills have been proven to host up to 12 unique species of plants, lizards, and insects, as well as my specialty, bats. Furthermore, up to 90% of species in some groups that depend on these hills for survival are estimated to be unknown to science.

Dr Alice Hughes observing the bat [Photo Credit: Chien C Lee]

Wait, why bats?

It’s common knowledge that bats inhabit caves. Often viewed as dead spaces, caves are in fact thriving, self-contained ecosystems as rich in life as anywhere on the planet, and the bulk of endemic species have a single energy source – bat guano. Without sunlight or significant plant life, bats, through their daily foraging, bring home takeaway meals for a myriad of cave species.

Bat foraging also plays a key role in pollinating millions of pounds worth of regional cash crops, including the fragrant durian and hardwoods like Iroko. They disperse seeds and eat billions of pest insects, including agricultural pests and spreaders of disease. Friends to farmers and conservationists alike, bats are essential to maintaining viable ecosystems and even reforesting degraded areas.

Bats are also uniquely fascinating creatures. They have the longest pregnancies and biggest babies for their body size of any mammal (25% of their mother’s weight at birth), live up to 10 times longer than similarly-sized mammals – up to 40 years in the wild – and appear to have beaten the ageing process, with elderly bats almost indistinguishable physically from teenagers. Bats also have a suite of adaptations to a high energy lifestyle, with aerodynamic and sonar abilities so advanced that much bat research is military funded.

There are over 1,320 known species of bat, making them the second largest mammalian group after rodents. The smallest could sit comfortably on your fingertip and weighs 1.5 grams, the biggest individuals have 1.8 metre wingspans. They come in almost every color and occupy almost all terrestrial habitats. They are so numerous and diverse, and challenging to tell apart, that in Southeast Asia we have only described around half the total number of species.

So what are we doing?

Our research in China, Myanmar, Thailand, Malaysia, Indonesia and beyond covers many different aspects of Southeast Asian biodiversity, but our work on bats is a special focus because of their importance and our lack of knowledge. It’s vital we work internationally because without a full regional picture of habitat loss governments can’t develop cohesive strategies for responding to threats to biodiversity.

The UK Research and Innovation-China Biosphere, Evolution, Transitions and Resilience project, which I also work on at the Xishuangbanna Tropical Botanical Garden, uses comprehensive field and lab work and cutting-edge modeling software to develop strategies to help protect species and systems in ever more uncertain conditions by looking at extended timescales – from 45 million years ago up to the present day – to chart how species like bats respond to different stressors. This kind of international partnership allows the best environmental scientists to pool their resources and work across borders and disciplines to respond to global challenges. Beyond BETR, UK Research and Innovation, for example, has funded more than 40 projects involving the Chinese Academy of Sciences and its Institutes – a combined investment of over 250 million yuan.

One of our group’s major projects is on mapping out limestone hills across Southeast Asia, then collaborating with researchers who work on similar terrain to try to establish a clear map of regional biodiversity. We prioritize the most uniquely biodiverse karsts, as an estimated 6% of regional karsts are lost every year and very few are protected. We are developing tools to help us better monitor these systems, such as a “bat cave vulnerability index,” which combines threat and biodiversity to try to find a standardized way to prioritize caves for protection – without bats, entire cave ecosystems would go extinct.

We are also developing new ways to monitor species inside and outside caves, using new technology to automate processing of bat calls. Bat calls are like acoustic fingerprints, and having developed a reference library of calls we can now feed acoustic recordings into a program we have developed to analyze what species are present in any given area, and how abundant they are. Soon, we will use this method to survey bat activity across the whole of China’s Yunnan Province, tracking migration patterns as well as fluctuations in diversity and total population.

Our ecosystem level work also looks at how the landscape interacts with conditions on the limestone karsts. For example, we use data loggers to see how deforestation relates to microclimate on each limestone hill, and how this impacts its ability to maintain stable conditions and thus its endemic specialist species. If the local bat population drops, farmers might see a fall in crop yields – devastating to small, regional communities dependent on agriculture.

Why is this useful?

Much of our research aims to explore the links between species and their environment. Our goal is to use this information to better assess the likely impacts of future human development and climate change, and to preserve what we can of Earth’s biodiversity for future generations. The tools and methods we are developing can feed directly into how we can protect this area’s unique diversity by enabling an understanding of why species are present and what major threats they face.

These systems may be threatened by multiple stressors, so that both human action and pressures such as climate change act in concert – a ‘perfect storm’. In our work, we use multiple measures to understand how species have responded to past changes and follow the fossil record to trace back millions of years of climate change to infer how present-day ecosystems might react to future changes, and how we can maintain the greatest number of species.

For many species, bats included, the risks to their future survival have never been more acute. But by working together across disciplines and cultures to develop tools and standards, we can develop methods which best safeguard the biodiversity of one of the world’s most biodiverse and threatened regions. Rather than focusing on just big species like the tiger, we use smaller, yet often more important species like bats, bees and beetles as our indices of habitat health so we can understand what we can, and should, make the greatest efforts to protect. These invaluable, understudied organisms may act as the fluffy, fanged canaries in the coal mine that warn of coming changes in these unique ecosystems, allowing for more timely and scientific interventions which best safeguard biodiversity.

Dr Alice Hughes is currently collaborating with the University of Bristol School of Geography on the Biosphere, Evolution, Transitions and Resilience (BETR)programme jointly funded by NERC and NSFC which aims to understand patterns and processes of biodiversity and the evolutionary processes involved for a large part of Asia. Her work is partly funded by the Chinese Academy of Sciences (CAS) and she is based at the CAS Xishuangbanna Tropical Botanical Garden in Yunnan Province, China.

Source: UK Research and Innovation China