Unveiling the Conservation Biogeography of a Data-Deficient Endangered Bird Species under Climate Change

<div><p>It remains a challenge to identify the geographical patterns and underlying environmental associations of species with unique ecological niches and distinct behaviors. This in turn hinders our understanding of the ecology as well as effective conservation management of threatened species. The white-eared night heron (<i>Gorsachius magnificus</i>) is a non-migratory nocturnal bird species that has a patchy distribution in the mountainous forests of East Asia. It is currently categorized as “Endangered” on the IUCN Red List, primarily due to its restricted range and fragmented habitat. To improve our knowledge of the biogeography and conservation of this species, we modeled the geographical pattern of its suitable habitat and evaluated the potential impacts of climate change using ecological niche modeling with a maximum entropy approach implemented in Maxent. Our results indicated that the amount of suitable habitat in all of East Asia was about 130 000 km², which can be spatially subdivided into several mountain ranges in southern and southwestern China and northern Vietnam. The extent of suitable habitat range may shrink by more than 35% under a predicted changing climate when assuming the most pessimistic condition of dispersal, while some more suitable habitat would be available if the heron could disperse unrestrainedly. The significant future changes in habitat suitability suggested for <i>Gorsachius magnificus</i> urge caution in any downgrading of Red List status that may be considered. Our results also discern potentially suitable areas for future survey efforts on new populations. Overall, this study demonstrates that ecological niche modeling offers an important tool for evaluating the habitat suitability and potential impacts of climate change on an enigmatic and endangered species based on limited presence data.</p></div

Disagreement of projected habitat suitability between current and future scenarios.

<p>The disagreement is calculated as the divergence of habitat suitability of <i>Gorsachius magnificus</i> between current and future climate conditions under the A2a (panel a) and B2a (panel b) climate scenarios. The negative values represent that the habitat is less suitable in future than in current, while the positive values represent the habitat is more suitable in future than in current.</p

Predicted habitat suitability for <i>Gorsachius magnificus</i> under the projected climate scenarios in 2050.

<p>These predictions are obtained with an ensemble-forecast approach across the three general circulation models CCCMA, CSIRO and HADCM3 of the climate scenarios under the two storylines (A2a and B2a).</p

MOESM1 of Inferring ecological explanations for biogeographic boundaries of parapatric Asian mountain frogs

Additional file 1. Distributions for occurrence records of Feirana quadranus and F. taihangnica in environmental space (annual mean temperature versus total annual precipitation)

MOESM2 of Inferring ecological explanations for biogeographic boundaries of parapatric Asian mountain frogs

Additional file 2. Filtering environmental variables

Comparison values of bioclimatic variables in projected suitable range between current and future climate scenarios.

<p>The black solid horizontal line represents the median, the square symbol represents the mean, edges of box are quartiles, whiskers are the 1th and 99th percentiles and black short lines are minimum and maximum.</p

Impacts of climate change on the habitat suitability along the latitude.

<p>Panels a and b represent the projected impacts for <i>Gorsachius magnificus</i> under two future climate scenarios (A2a and B2a; blue, current suitable ranges projected to be stable; red, suitable ranges projected to be lost; and green, the suitable ranges projected to be newly gained), respectively. The panels c and d represent the percentage of range lost. The predicted suitability is estimated based on the average training presence threshold.</p

Study area and predicted habitat suitability for the endangered white-eared night heron <i>Gorsachius magnificus</i>.

<p>The suitability is displayed in logistic value and ranges from 0 (lowest suitability) to 1 (highest suitability). Blue circles indicate known occurrence records. The Arabic numerals indicate locations of the significant mountain ranges mentioned in this study: 1, Shennongjia Mt.; 2, Dabie Mt.; 3, Huangshan-Tianmu Mt.; 4, Yandang-Wuyi-Daiyun Mt.; 5, Mufu-Jiuling-Luoxiao Mt.; 6, Nanling Mt.; 7, Wuling-Xuefeng-Miaoling Mt.; 8, Dayaoshan Mt.; 9, Limuling-Wuzhishan Mt.; 10, Shiwan'dashan Mt.; 11, Ban Thi & Xuan Lac; 12, Ailao Mt.</p

Discrepancy of suitability, altitude, longitude and latitude for predicted distribution between current and future scenarios.

<p>The minimum, mean, and maximum of suitability (a), altitude (b), longitude (c), and latitude (d) for predicted distribution of <i>Gorsachius magnificus</i> are exhibited. Red, green and blue represent current, A2a and B2a scenarios, respectively.</p

The sketch map of the study region in Asia.

<p>Current distribution ranges are indicated for the tribes Paini (red dotted line) and Quasipaini (black dotted line).</p