A Neighborhood Approach for Using Remotely Sensed Data to Estimate Current Ranges for Conservation Assessments

TL;DR

A new method called the neighborhood approach improves conservation assessments by refining habitat data to account for geolocation uncertainty in species range estimates.

Contribution

The novel neighborhood approach processes habitat data to maintain fine resolution while accounting for larger surrounding areas, improving conservation range estimates.

Findings

The neighborhood approach was applied to a forest-dwelling species, suggesting it should be removed from threatened categories based on refined habitat metrics.

Localized habitat loss patterns were revealed that are not captured by standard IUCN metrics like EOO and AOO.

The method is broadly applicable to various habitats and species with high georeferencing uncertainty.

Abstract

Species distribution modeling can be used to predict environmental suitability, and removing areas currently lacking appropriate vegetation can refine range estimates for conservation assessments. However, the uncertainty around geographic coordinates can exceed the fine resolution of remotely sensed habitat data. Here, we present a novel methodological approach to reflect this reality by processing habitat data to maintain its fine resolution, but with new values characterizing a larger surrounding area (the “neighborhood”). We implement its use for a forest‐dwelling species (Handleyomys chapmani) considered threatened by the IUCN. We determined deforestation tolerance threshold values by matching occurrence records with forest cover data using two methods: (1) extracting the exact pixel value where a record fell; and (2) using the neighborhood value (more likely to characterize conditions within the radius of actual sampling). We removed regions below these thresholds from the climatic suitability prediction, identifying areas of inferred habitat loss. We calculated Extent of Occurrence (EOO) and Area of Occupancy (AOO), two metrics used by the IUCN for threat level categorization. The values estimated here suggest removing the species from threatened categories. However, the results highlight spatial patterns of loss throughout the range not reflected in these metrics, illustrating drawbacks of EOO and showing how localized losses largely disappeared when resampling to the 2 × 2 km grid required for AOO. The neighborhood approach can be applied to various data sources (NDVI, soils, marine, etc.) to calculate trends over time and should prove useful to many terrestrial and aquatic species. It is particularly useful for species having high coordinate uncertainty in regions of low spatial autocorrelation (where small georeferencing errors can lead to great differences in habitat, misguiding conservation assessments used in policy decisions). More generally, this study illustrates and enhances the practicality of using habitat‐refined distribution maps for biogeography and conservation.

We created a neighborhood approach for processing habitat data used in conjunction with species distribution modeling to improve range estimates for conservation assessments.

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