Research Article |
Corresponding author: Felipe Pessoa Da Silva ( felipe.pessoas@gmail.com ) Corresponding author: Hugo Fernandes-Ferreira ( hugofernandesbio@gmail.com ) Corresponding author: Martín Alejandro Montes ( martinmontes76@gmail.com ) Corresponding author: Lucas Gonçalves da Silva ( lucas_gonc@yahoo.com.br ) Academic editor: Murilo Guimarães
© 2020 Felipe Pessoa Da Silva, Hugo Fernandes-Ferreira, Martín Alejandro Montes, Lucas Gonçalves da Silva.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Da Silva FP, Fernandes-Ferreira H, Montes MA, da Silva LG (2020) Distribution modeling applied to deficient data species assessment: A case study with Pithecopus nordestinus (Anura, Phyllomedusidae). Neotropical Biology and Conservation 15(2): 165-175. https://doi.org/10.3897/neotropical.15.e47426
|
The arboreal frog Pithecopus nordestinus is geographically present in almost all Brazilian Northeast territory and Minas Gerais State. It is currently classified as deficient data (DD) by IUCN Red List of Endangered Species, requiring further knowledge about its geographic distribution and population status. In this context, the species distribution modeling can be applied, since its basis uses species occurrence records and environmental variables related to bioclimatic and landscape features. This kind of method predicts the species suitability of certain organism in the geographic space. We obtained 159 P. nordestinus occurrence records, covering all the previously known distribution of the species. These records were collected from direct field sampling, scientific literature, museum collections, and available online databases. We used four species distribution modeling algorithms to obtain the potential range (extent of occurrence) and available habitat for this frog through habitat area analysis proposed by IUCN. The generated models can be considered as excellent, with mean AUC value of 0.981. The environmental variables related to temperature and radiation were the most important to the construction of this distribution model. Our results indicate that the forested areas of the Atlantic Forest domain and forest patches inside the Caatinga biome present the highest suitability values for the species occurrence and the major part of available habitats, a fact possibly related to the known arboreal habit of this amphibian. We thus provide a new distribution area for P. nordestinus more broadly than previously known and a new polygon for conservation purposes based on extent of occurrence, and an increase of occupancy based on habitat area analysis. The identification of additional areas where the P. nordestinus occurrence was not yet well known, new habitats for possible dispersal or recolonization; and the selection of conservation hotspots applied to this species are direct applications from our study. In addition, the methodological procedures used here may serve as a baseline tool for new investigations with focus on still deficient data species and its ecological and conservation planning requirements.
Amphibia, conservation planning, ecological niche, ensemble modeling
The IUCN Red List of Threatened Species is one of the most important and relevant tools for biodiversity, as well as a source of information about the status of the worldwide fauna and flora, which supports decision making in conservation planning. A single species can be allocated in only one of the different extinction risk categories ranging from low to high potential. When there is insufficient and/or inadequate information to make an effective assessment of its status, either directly or indirectly from the species distribution and population information, the taxa can be classified as ‘deficient data’ (“DD”). The taxa classified as DD may require urgent conservation actions, yet this is not a threat category and conservation actions may not be directed at prioritizing, or focusing on, this species (
The last valid and available IUCN assessment about Anura evaluated the conservation status of more than 6.000 species and, currently, 21.32% of them are categorized as DD. Out of this total DD species, 11% of them occur in the Neotropics. Phyllomedusidae is endemic from the Neotropics. In this family, Pithecopus Cope, 1866 is represented by five distinct species (
The small anuran Pithecopus nordestinus (Caramaschi, 2006) is characterized by the predominant arboreal habits, and can be distinguished from other similar species by its color combination pattern, such as the black vertical bars above the red-orange background in the flank hidden parts and limbs. The species is distributed throughout the northeastern region of Brazil, occupying most of the Caatinga biome and adjacent regions in the states of Alagoas, Bahia, Ceará, Minas Gerais, Paraíba, Pernambuco, Piauí, Rio Grande do Norte e Sergipe (
Knowledge about the geographical distribution of a species is a fundamental tool for the foundation of evolutionary and ecological studies. Species distribution models use the ecological niche as baseline (
Recent occurrences have been recorded to P. nordestinus (
The construction of the database containing P. nordestinus occurrence records was performed by field surveys, a probe into the scientific literature, museum vouchers, and online databases such as GBIF (http://www.gbif.org) and SpeciesLink (http://splink.cria.org). The current nomenclature and previous synonymy of the species, “Pithecopus nordestinus” and “Phyllomedusa nordestina”, respectively, were used as search keywords in all databases. Also, only geo-referenced occurrences of the target species were used in the analyses. We obtained a total of 159 unique and representative records to build the model from the entire P. nordestinus range (Figure
In the modeling procedures we initially considered 36 bioclimatic variables obtained from the WorldClim (http://www.worldclim.org/) and CliMond databases (
The distribution models were produced using ensembles from several algorithms implemented in Biomod2 package (
The final polygon was built overlapping the new points of occurrence, the IUCN polygon and the models built, and then drawing the minimum convex polygon.
The EOO and AOO were calculated using the package “red – IUCN red listing tools” (
Approximately 55% of the occurrences for the species were located within the Caatinga biome, 40% in the moist Atlantic Forest and 3% in dry Atlantic Forest and have also recorded occurrences in the Cerrado (2%) (Figure
The distribution model generated for P. nordestinus in our study provided satisfactory predictive powers, with an average of AUC = 0.973 (± 0.038) and TSS 0.834 (± 0.064). The model shows a greater suitability for P. nordestinus especially in areas of moist Atlantic Forests in the coastal portion of northeast Brazil and dominated forest patches of Caatinga and Cerrado biomes (Figure
The current available IUCN polygon (
Partial map of northeast Brazil containing: (A) Pithecopus nordestinus location records overlaid with biomes based on
Relative importance of bioclimatic variables used to generate distribution models for Pithecopus nordestinus into the software Maxent.
Variable | Percent Contribution |
---|---|
Temperature annual range (bio7) | 32.4 |
Annual mean radiation (bio20) | 17.5 |
Radiation of driest quarter (bio25) | 11.2 |
Temperature seasonality (bio4) | 8.9 |
Mixed/Other Trees | 6.5 |
Annual precipitation (bio12) | 5.5 |
Shrubs | 5.4 |
Radiation of coldest quarter (bio27) | 4.5 |
Evergreen Broadleaf Trees | 2.6 |
Altitude | 2.2 |
Mean moisture index of driest quarter (bio33) | 2.4 |
Mean temperature of warmest quarter (bio10) | 2 |
The high AUC and TSS values obtained (above 0.80) indicates that all models were able to roughly estimate the geographic distribution of the species as ranked by
The species is still considered as data deficient at global level, so, comparing the two polygons, we can highlight an expansion of the potential distribution of the species to the southern coast of Bahia State, and the western part of the Brazilian northeastern region. Through the association between the species distribution model and AOH obtained in our analyses, we identified realistic suitable areas inside the known occurrence limits of the species (Figure
Previous studies on ecological niche modeling for reptiles (
We propose an increase in the distributional suitable area for P. nordestinus previously described by recent studies. The environmental variables that best explain the distribution of this species are related to temperature (mainly), radiation and moisture. Additionally, the distribution can be influenced by the landscape conformation and habitat availability (
The authors would like to thank Werlyson Pinheiro, Érica Demondes, Carlos Bezerra Neves and Isabella Ribeiro for their scientific support; and Ednilza Maranhão dos Santos for providing the photograph included in this article. This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001 (Felipe Pessoa da Silva); by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and FACEPE (Martín Alejandro Montes and Lucas Gonçalves da Silva).
Table S1
Data type: Occurrences
Explanation note: Pithecopus nordestinus location records used in the present study.