Potential distribution of Aquila chrysaetos in Mexico: Implications for conservation

Abstract

The golden eagle (Aquila chrysaetos) has been poorly studied in Mexico. Even though it is listed as threatened in this country, partly because of habitat fragmentation and direct persecution, little is known of its distribution. We assessed the potential distribution of this species in Mexico using ecological niche modelling (ecological niche factor analysis, artificial neural network, genetic algorithm for rule-set production, environmental distance, support vector machine, MaxEnt) and the weighted average ensemble method. The models were evaluated using the area under the curve of the receiver operating characteristics. We applied a threshold of 50% probability to obtain high-suitability areas and considered marginality and specialization calculated by ecological niche factor analysis and the most important variables to the model. We assessed and evaluated the percentage of high-suitability area occurring in all Mexican natural protected areas. The performance of the ensemble model was high (area under the curve = 0.93) and the most important variables contributing to the model were grasslands and tree cover percentage. The resulting high-suitability area is considerably fragmented, it comprises 16% of the country and just 8% of it is located in natural protected areas. We propose some urgent actions and conservation measures to face the main problems that are threatening the species in Mexico.

Protecting breeding sites: a critical goal for the conservation of the golden eagle in Mexico under global change scenarios

“…The current study is the first to explore the impact of both climate and land-use changes on a top predator species such as the Golden Eagle, even providing novel information about breeding parameters for its population over time. Worryingly, our results suggest a concerning scenario for this emblematic species due to the reduction of range size and the increase in fragmentation across Mexico (Rodríguez-Estrella 2002;Campos-Rodríguez et al 2019;D'Addario et al 2019;Bautista et al 2022). This is not substantially improved by the existing PA network; on one hand, Mexican PAs are not fully exempt from human disturbance and climate change, and on the other, most of the sites (including breeding areas) that are highly resilient to climate and land-use changes are located outside of current PAs.…”

“…This has led to growing interest in identifying priority sites for their conservation. Despite the increase in knowledge of the distribution of Mexican Golden Eagle population over recent years, details about the combined effects of anthropogenic disturbances and global climate warming on geographic and ecological patterns for this species are scarce (Rodríguez-Estrella 2002;Bravo-Vinaja and Guzmán-Aranda 2014;D'Addario et al 2019;Campos-Rodríguez et al 2019).…”

Ecological correlates of Golden Eagle Aquila chrysaetos breeding occurrence in Sardinia

“…Finally, the negative association of the species distribution with environmental complexity (as explained by the variable 'mean fractal dimension') could indicate the preference of Golden Eagles for large portions of continuous suitable habitat and, therefore, the threat produced by habitat fragmentation and shrinkage of suitable habitat patches (Watson 2010, Katzner et al 2012a, D'Addario et al 2019. This is particularly important in Sardinia, where very frequent summer arson (Nudda et al 2015) and land abandonment can favour habitat fragmentation in many otherwise suitable areas of the island (PAF 2014).…”

A renewed glance at the Palearctic golden eagle: Genetic variation in space and time

“…As a consequence of conservation efforts and the species' extensive range, the golden eagle is currently classified as Least Concern by the International Union for Conservation of Nature (IUCN) both globally, and in Europe (BirdLife International, 2023 ). The classification reflects the overall stability, but regional populations continue to face local threats, such as habitat destruction, human disturbances, use of lead bullets and pesticides, collisions with wind turbines, and illegal trade (D'Addario et al., 2019 ; Slabe et al., 2022 ; Watson, 2010 ). Unfortunately, some vast regions within the species' distribution, such as Russia and much of Asia, are lacking data on golden eagles, limiting conservation efforts.…”