Batch-produced, GIS-informed range maps for birds based on provenanced, crowd-sourced data inform conservation assessments

Abstract

Accurate maps of species ranges are essential to inform conservation, but time-consuming to produce and update. Given the pace of change of knowledge about species distributions and shifts in ranges under climate change and land use, a need exists for timely mapping approaches that enable batch processing employing widely available data. We develop a systematic approach of batch-processing range maps and derived Area of Habitat maps for terrestrial bird species with published ranges below 125,000 km2 in Central and South America. (Area of Habitat is the habitat available to a species within its range.) We combine existing range maps with the rapidly expanding crowd-sourced eBird data of presences and absences from frequently surveyed locations, plus readily accessible, high resolution satellite data on forest cover and elevation to map the Area of Habitat available to each species. Users can interrogate the maps produced to see details of the observations that contributed to the ranges. Previous estimates of Areas of Habitat were constrained within the published ranges and thus were, by definition, smaller—typically about 30%. This reflects how little habitat within suitable elevation ranges exists within the published ranges. Our results show that on average, Areas of Habitat are 12% larger than published ranges, reflecting the often-considerable extent that eBird records expand the known distributions of species. Interestingly, there are substantial differences between threatened and non-threatened species. Some 40% of Critically Endangered, 43% of Endangered, and 55% of Vulnerable species have Areas of Habitat larger than their published ranges, compared with 31% for Near Threatened and Least Concern species. The important finding for conservation is that threatened species are generally more widespread than previously estimated.

The potential of ecoregional range maps for boosting taxonomic coverage in large-scale ecology and conservation

“…through the consideration of elevational ranges or measures of spatial distance (e.g. Huang et al, 2021, Palacio et al, 2021. However, we herein focused on a simple and readily applicable approach to provide a solution most useful for poorly documented species and that avoids circularity with environmental niche models (e.g., SDMs).…”

“…However, given the immense workload to produce ExpRMs, the limited number of experts available to inform them, and the sheer number of species on Earth, there is an increasing interest in automating and facilitating their production. Specifically, several recent studies suggested the use of MCVs or similar approaches as surrogates for species' ranges (Dauby et al, 2017;Huang et al, 2021;Palacio et al, 2021). Nevertheless, to our knowledge, their performance has not been evaluated before.…”

“…Integrative models combining SDMs with range estimates such as the approach presented by Merow et al ( 2017) may directly include EcoRM offsets to better define sampling regions for pseudo-absences and to evaluate the appropriateness of the range offset with different distance decay parameters. Other nonparametric attempts to resolve the internal structure of range maps using presence/absence data, elevational ranges, and measures of spatial proximity (e.g., Huang et al, 2021, Palacio et al, 2021 ultimately face the same limitations -of highly inaccurate and spatially biased occurrence data -as SDMs and even stronger limitations of data availability due to a lack of absence information. The advantages of EcoRMs, particularly for data-poor species, suggest that the integration of ecoregional offsets into SDMs would likely improve models for 26% of all butterfly species, for example [i.e.…”

Distribution and habitat assessment of an Endangered hummingbird: the Grey-bellied Comet Taphrolesbia griseiventris

“…Assessing current and potential distribution helps conservation action in known localities and directs future searches for sites with a high probability of occurrence. Accurate species distribution models and maps are increasingly proposed to support conservation decision-making (Guisan et al 2013, Huang et al 2021). These also contribute to assessing the species extinction risk by adding important information to this process, such as the size of the population, area of occupancy and occurrence, and locations (IUCN 2022), and contribute to protected area design and establishment.…”

Using the area of habitat to assess the extent of protection of India's birds

“…Simultaneously, GIS datasets that map elevations and the extent of habitats, especially forest cover, have also improved. These advances in species' observations and measurement of habitat now allow us to assess better where species occur, which are at risk, and where conservation priorities lie (Huang et al, 2021).…”