Hummingbirds, quetzals, and macaws are some of the most stunning birds in South America. When considering how threatened a species is, researchers often start with a map of the species’ geographical distribution, or range, which provides information on where they occur and, therefore, the threats they face. But ‘where’ is not the only thing that is important. Size matters too. Species with smaller range sizes tend to also have smaller populations, scarce remaining habitat, and hence, are usually more threatened with extinction.
In a paper published on October 5, 2021, in the peer-reviewed journal Diversity & Distributions, the researchers propose a new automated workflow for drawing a species’ distribution. The aim of the new workflow is to provide a data-driven method to map species’ distributions with increased precision and in a reproducible way. More accurate range maps, particularly for lesser-known species or species with small range sizes, can greatly benefit threatened species and generate needed conservation attention.
“Accurately estimating species distributions, and updating them regularly over time, is one of the best ways to track how species are faring” argues lead author and Duke University PhD student Ruben Dario Palacio. “In order to understand the diversity of life on this planet, and its status, we need maps. Therefore, it is critical to assess the process in which species’ range maps are made, and to re-think the way range maps are made, as necessary, over time.”
Palacio, who is also science director of Fundacion Ecotonos, a conservation non-profit in Colombia, adds: “Unfortunately, most distribution maps have been hand-drawn by a small team of experts based on their judgement and knowledge of a species’ habitat preferences. While this process can be highly accurate, and is how most existing range maps have been done, it is also time-consuming and idiosyncratic. There are more than 10,000 species of bird and millions more species of various shapes and sizes. Simply put, time, data and skill are luxuries we don’t have. We need accurate, regularly updated range maps that can track change over time.”
The proposed workflow provides just that standardized alternative to hand-drawn range estimates and can map the distribution of many species in a fast and repeated fashion. It consists of a five-step process that refines the estimation of a species distribution into a tightly drawn map of likely areas of habitat surrounding known presence points. Tested on over 700 birds in the Americas, the workflow proved to be more accurate than traditional expert-drawn maps and can be implemented by anyone with basic knowledge in Geographic Information Systems.
Professor Andrew Jacobson of Catawba College, and senior author of the study, says, “I’ve worked on creating the range maps of some of the most iconic species on the planet – the lion, cheetah and leopard. Yet, the process for each species required years of effort and dozens of experts before an updated map was produced. This approach simply is not workable for the vast majority of life on Earth.”
Jorge Velásquez-Tibatá, an author on this study and researcher at Audubon Americas, has already begun using this approach for conservation purposes. “This new workflow is helping our organization to identify areas that are important both for migratory and resident birds in Latin America that would be eligible for funding under Conserva Aves, a multi-partner initiative to protect 2 million hectares of critical bird habitat across Latin America. This new approach is just what we need to move quickly and confidently in protecting threatened species.”