In 2017, a group of scientists sounded alarm bells by showing that flying insects have declined in Germany by more than 70% in the previous three decades. Studies before and after showed similar patterns in insects on a global scale. But with a million known species – and conservative estimates suggesting there are millions more waiting to be discovered – there aren’t enough entomologists to document the full range of insects’ diversity, let alone how their populations have changed over time.
In a new study, entomologists turn to the help of park rangers in Ecuador’s Yasuni National Park, widely considered one of the most biodiverse ecosystems on the planet. Researchers, students, and park staff have been actively involved in monitoring the abundance of butterflies in Yasuni since 2016 in an ongoing project that flips the script on the way most survey efforts are conducted in the tropics.
“This study has clear benefits for science and conservation, but it was also important to include the social benefits of the people we worked with,” said lead author Maria Chica, a researcher at the Pontifical Catholic University of Ecuador and a former doctoral student at the University of Ecuador. Florida Museum of Natural History.
“We still know little about the effects of environmental change in the tropics, because we simply do not have enough experienced researchers to study these regions,” she said. “We need to empower local actors with this knowledge, because they are the key stakeholders in conservation.”
Building alternatives to canopy biology
Many scientists who focus on conservation often encounter a snag early in their endeavors: Most of the world’s biodiversity is unevenly distributed in the tropics, but the majority of researchers who study it live primarily in temperate regions. As a result, the flora and fauna of many industrialized countries are relatively well studied and benefit from extensive monitoring programmes, such as the decades-old survey of insect population declines in Germany.
A similar program using butterflies as a substitute for insect community health was launched in the UK in 1976 and has since been adopted in at least 19 other European countries. These ongoing surveys provide scientists with a wealth of data, but the patterns they reveal provide only a small snapshot of changes occurring globally.
“In Great Britain, you’re dealing with fewer than 60 species of butterflies, while in Yasuni alone there are more than 1,500,” said senior author Keith Wilmot, curator and director of the McGuire Center for Lepidoptera and Biodiversity at the Florida Museum.
Scientists from many industrialized countries have tried to offset this imbalance by conducting short-term projects in tropical ecosystems, often paying local residents to help with surveys and collections. This practice, sometimes called canopy biology, can yield important scientific insights. But when the project ends or funding runs out, the researchers go back to their institutions, and the residents go back to their normal lives.
Wilmot says that these limited surveys will not be enough to effectively monitor long-term population trends and help avert what is currently the worst extinction event since the death of the dinosaurs.
“Trying to understand patterns of abundance in a tropical community where climate seasonality and myriad complex interactions are reduced is incredibly complex and requires long-term data sets,” he said.
However, starting and continuing these programs is not always an option in remote areas where human numbers are scarce. So when park rangers expressed interest in helping the Yasuni butterflies in 2015, Wilmott saw the potential for a wide-ranging partnership.
“Ecuador is full of national parks that have pristine forests, and part of the work responsibilities of many park rangers is to conduct biodiversity monitoring. It seemed to us that this was a potential solution to the expenses and logistics of running these projects,” he said.
Butterflies are the perfect early warning system
Even with the help of park rangers, there is no realistic way to sample the diversity of the entire rainforest. Instead, biologists rely on pointer types, organisms that are widely distributed and easy to find but sensitive enough to environmental change that they can be used to infer how related groups are performing.
For insects, those indicator species are butterflies.
“There are a number of reasons why they provide good pointers,” Wilmott said. “They can be found almost everywhere, they are incredibly diverse and reflect what happens in other living things.”
Butterflies occupy a central role in maze-like ecosystem networks. Most of them depend exclusively on plants for food, and the plants, in turn, depend on butterflies for pollination. Caterpillars and butterflies are also a good meal for predators higher in the food chain. If you take butterflies out of the equation, the networks that bind natural communities together begin to break down. This makes it the perfect test to measure the health of an ecosystem.
Butterflies have another feature that helps them stand out from the crowd. “From a practical point of view, there is no doubt that it is by far the easiest group of insects to identify,” Wilmot said. In a place as diverse as Ecuador, this last ingredient is a must.
Park Rangers collect and collect diversity data
Working with Chica, Willmott and co-author Sophia Nogales of the National Institute of Biodiversity in Ecuador and their colleagues, rangers quickly learned how to collect butterflies using bait traps and identify the most common species. Since 2017, they have conducted regular surveys with accuracy rates similar to those of trained field biologists. But their contribution to the study did not end there.
“The custodians wanted to be more involved with the project, so we started talking about writing a manuscript together,” Chica said. “We set up a workshop in Quito where we introduced computers and taught them how to perform basic statistical analyzes on butterfly data.”
For Chica, the project represents an important shift in the way biodiversity is monitored in her home country, Ecuador, which she hopes will help protect sensitive ecosystems and give a voice to those who inhabit them.
“People who live in rural areas near protected forests often lack resources and opportunities for formal training. It is difficult for many to finish secondary school,” she said. “We are talking about the decentralization of knowledge from academic institutions to local populations and from cities to rural areas.”
Rangers of Yasuni National Park, three of whom are co-authors of this study, are currently working on analyzing the data they continue to collect, which they plan to publish in an upcoming article. “We are proud to be the first park rangers in Ecuador to implement a successful long-term monitoring program – this project has enriched our knowledge of biodiversity and the importance of insects in ecosystems, especially butterflies, helping us better carry out our work,” said co-author Leslie Bustos.
Ongoing support from the National Park Administration has been and continues to be critical to the project’s success. Chica and Willmott hope to expand their butterfly monitoring to additional protected areas within Ecuador in the near future.
The researchers published their findings in Conservation of insects and diversity.
Park Rangers Fernardo Ojeda and Alci Bustos are co-authors of the study, as well as Patricio Salazar of the University of Sheffield.
Transparent butterfly map highlights biodiversity hotspots in the Andes
Maria F. Checa et al., Implementation of a New Approach to Long-Term Monitoring of Butterfly Communities in Neotropics, Conservation of insects and diversity (2022). DOI: 10.1111 / icad.12567
Presented by the Florida Science Museum
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