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Geographic range estimates and environmental requirements for the harpy eagle derived from spatial models of current and past distribution

Citation

Sutton, Luke (2021), Geographic range estimates and environmental requirements for the harpy eagle derived from spatial models of current and past distribution, Dryad, Dataset, https://doi.org/10.5061/dryad.9cnp5hqgn

Abstract

Understanding species-environment relationships is key to defining the spatial structure of species distributions and develop effective conservation plans. However, for many species this baseline information does not exist. With reliable presence data, spatial models that predict geographical ranges and identify environmental processes regulating distribution are a cost-effective and rapid method to achieve this. Yet these spatial models are lacking for many rare and threatened species, particularly in tropical regions. The harpy eagle (Harpia harpyja) is a Neotropical forest raptor of conservation concern with a continental distribution across lowland tropical forests in Central and South America.Currently the harpy eagle faces threats from habitat loss and persecution and is categorised as Near-Threatened by the International Union for the Conservation of Nature (IUCN). Within a point process modelling (PPM) framework, we use presence-only occurrences with climatic and topographical predictors to estimate current and past distributions and define environmental requirements using Ecological Niche Factor Analysis. The current PPM prediction had high calibration accuracy (Continuous Boyce Index = 0.838) and was robust to null expectations (pROC ratio = 1.407). Three predictors contributed 96 % to the PPM prediction, with Climatic Moisture Index the most important (72.1 %), followed by minimum temperature of the warmest month (15.6 %) and Terrain Roughness Index (8.3 %). Assessing distribution in environmental space confirmed the same predictors explaining distribution, along with precipitation in the wettest month. Our reclassified binary model estimated a current range size 11 % smaller than the current IUCN range polygon. Paleoclimatic projections combined with the current model predicted stable climatic refugia in the central Amazon, Guyana, eastern Colombia, and Panama. We propose a data-driven geographical range to complement the current IUCN range estimate, and that despite its continental distribution this tropical forest raptor is highly specialized to specific environmental requirements.

 

Methods

Environmental data available from:

WorldClim (v1.4) current: https://www.worldclim.org/data/v1.4/worldclim14.html

WorldClim (v1.4) paleoclimate: https://www.worldclim.org/data/v1.4/paleo1.4.html

ENVIREM: http://envirem.github.io/#downloads

Occurrence data available from:

GBIF: https://www.gbif.org/species/2480516

eBird: https://ebird.org/data/download/ebd

Miranda et al. (2019) database: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0216323#sec011

Usage Notes

R code to run the analyses is available on request from the corresponding author.