TY - JOUR
T1 - The amphibian-killing fungus in a biodiversity hotspot
T2 - identifying and validating high-risk areas and refugia
AU - Bacigalupe, Leonardo D.
AU - Vásquez, Inao A.
AU - Estay, Sergio A.
AU - Valenzuela-Sánchez, Andrés
AU - Alvarado-Rybak, Mario
AU - Peñafiel-Ricaurte, Alexandra
AU - Cunningham, Andrew A.
AU - Soto-Azat, Claudio
N1 - Funding Information:
Leonardo D. Bacigalupe, C. Soto-Azat, and Andrés Valenzuela-Sánchez acknowledge funding from FONDECYT grants 1150029, 1181758, and 3180107, respectively. Sergio A. Estay acknowledges funding from FONDECYT 1160370 and CAPES FB-0002-2014 line 4. The authors declare they do not have any conflict of interest. We would like to thank Johara Bourke and Virginia Moreno who gave us unpublished information on Bd sampling sites and The Nature Conservancy for collaborating with us in sampling within the Reserva Costera Valdiviana. Special thanks to two anonymous reviewers whose comments greatly improved the manuscript. LDB and CSA conceived the idea and secured the funding for this project; LDB, IAV, and SAE designed the methodology; CSA, AVS, MAR, AAC, IAV, and APR completed the fieldwork, molecular analyses, and interpretation of laboratory results; IAV performed the analyses with input from SAE and LDB; LDB and IAV led the writing of the manuscript. All authors contributed critically to the drafts and gave final approval for publication. We declare we have no competing interests.
Funding Information:
Leonardo D. Bacigalupe, C. Soto-Azat, and Andrés Valenzuela-Sánchez acknowledge funding from FON-DECYT grants 1150029, 1181758, and 3180107, respectively. Sergio A. Estay acknowledges funding from FONDECYT 1160370 and CAPES FB-0002-2014 line 4. The authors declare they do not have any conflict of interest. We would like to thank Johara Bourke and Virginia Moreno who gave us unpublished information on Bd sampling sites and The Nature Conservancy for collaborating with us in sampling within the Reserva Costera Valdiviana. Special thanks to two anonymous reviewers whose comments greatly improved the manuscript. LDB and CSA conceived the idea and secured the funding for this project; LDB, IAV, and SAE designed the methodology; CSA, AVS, MAR, AAC, IAV, and APR completed the fieldwork, molecular analyses, and interpretation of laboratory results; IAV performed the analyses with input from SAE and LDB; LDB and IAV led the writing of the manuscript. All authors contributed critically to the drafts and gave final approval for publication. We declare we have no competing interests.
Publisher Copyright:
© 2019 The Authors.
PY - 2019/5/1
Y1 - 2019/5/1
N2 - Amphibian chytridiomycosis, due to infection with the fungus Batrachochytrium dendrobatidis (Bd), has been associated with the alarming decline and extinction crisis of amphibians worldwide. It is essential for conservation management to identify regions with high or low suitability for Bd. We use a species distribution model to estimate the environmental suitability of Bd in the Chilean Winter Rainfall–Valdivian Forest biodiversity hotspot. Fourteen environmental variables were used as predictors in the statistical modeling (Maxent, generalized linear models, random forest) which also included 56 independent Bd+ localities. High-risk areas (i.e., suitability above a defined threshold) were validated through prospective field surveys conducted in 2017. As results from Maxent, which only uses presence data, were the only results retained, refugia (i.e., suitability below a defined threshold) were validated with the Bd absences (N = 12) used in the GLM and RF modeling. Our results showed that (1) suitability for Bd increased with human footprint and with shorter distances to urban centers and water bodies and decreased with elevation; (2) climate was not a major factor shaping the current distribution of Bd; and (3) the model predicted high-risk and refugia areas fairly well. Surveys of 24 new localities in high-risk areas confirmed that 23 were Bd+; hence, these areas warrant consideration for long-term Bd surveillance, population monitoring, and disease mitigation. In addition, five localities with apparent Bd absence were found in the predicted high-risk areas. Our models showed that refugia can exist near high-risk areas and Bd+ sites. Four localities with apparent Bd absence were located within the refugia predicted by the model. Preventing Bd transmission to such refugia is of paramount importance for persistence of Bd-susceptible amphibian populations. The identification and validation through prospective field surveys of high-risk areas and refugia are imperative to develop strategies to prevent further arrival and establishment of Bd and also, by identifying amphibian species or populations of conservation concern in such areas, will help to guide specific actions to reduce the biodiversity loss caused by chytridiomycosis.
AB - Amphibian chytridiomycosis, due to infection with the fungus Batrachochytrium dendrobatidis (Bd), has been associated with the alarming decline and extinction crisis of amphibians worldwide. It is essential for conservation management to identify regions with high or low suitability for Bd. We use a species distribution model to estimate the environmental suitability of Bd in the Chilean Winter Rainfall–Valdivian Forest biodiversity hotspot. Fourteen environmental variables were used as predictors in the statistical modeling (Maxent, generalized linear models, random forest) which also included 56 independent Bd+ localities. High-risk areas (i.e., suitability above a defined threshold) were validated through prospective field surveys conducted in 2017. As results from Maxent, which only uses presence data, were the only results retained, refugia (i.e., suitability below a defined threshold) were validated with the Bd absences (N = 12) used in the GLM and RF modeling. Our results showed that (1) suitability for Bd increased with human footprint and with shorter distances to urban centers and water bodies and decreased with elevation; (2) climate was not a major factor shaping the current distribution of Bd; and (3) the model predicted high-risk and refugia areas fairly well. Surveys of 24 new localities in high-risk areas confirmed that 23 were Bd+; hence, these areas warrant consideration for long-term Bd surveillance, population monitoring, and disease mitigation. In addition, five localities with apparent Bd absence were found in the predicted high-risk areas. Our models showed that refugia can exist near high-risk areas and Bd+ sites. Four localities with apparent Bd absence were located within the refugia predicted by the model. Preventing Bd transmission to such refugia is of paramount importance for persistence of Bd-susceptible amphibian populations. The identification and validation through prospective field surveys of high-risk areas and refugia are imperative to develop strategies to prevent further arrival and establishment of Bd and also, by identifying amphibian species or populations of conservation concern in such areas, will help to guide specific actions to reduce the biodiversity loss caused by chytridiomycosis.
KW - Batrachochytrium dendrobatidis
KW - chile
KW - chytrid fungus
KW - chytridiomycosis
KW - emerging infectious diseases
KW - maxent
KW - pathogen mitigation strategy
KW - species distribution model
UR - http://www.scopus.com/inward/record.url?scp=85066488613&partnerID=8YFLogxK
U2 - 10.1002/ecs2.2724
DO - 10.1002/ecs2.2724
M3 - Article
AN - SCOPUS:85066488613
SN - 2150-8925
VL - 10
JO - Ecosphere
JF - Ecosphere
IS - 5
M1 - e02724
ER -
