Research Article |
Corresponding author: Kássio de Castro Araújo ( kassio.ufpi@gmail.com ) Academic editor: Uri García-Vázquez
© 2025 Kássio de Castro Araújo, Nayla Letícia Rodrigues Assunção, Mirco Solé, Etielle Barroso de Andrade.
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:
Araújo KC, Assunção NLR, Solé M, Andrade EB (2025) Assessing the effect of local heterogeneity on anuran diversity in the Serra da Capivara National Park, Piauí State, Brazil. ZooKeys 1236: 233-248. https://doi.org/10.3897/zookeys.1236.138858
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Anurans are among the most diverse groups of vertebrates globally, and environmental heterogeneity plays a key role in shaping their diversity patterns. This study aimed to update the anuran checklist of the Serra da Capivara National Park, Piauí State, northeastern Brazil, and investigate the influence of local heterogeneity on anuran abundance and richness. We recorded 16 anuran species across five families – Bufonidae, Hylidae, Leptodactylidae, Microhylidae, and Phyllomedusidae – most of which are typical Caatinga species or widely distributed taxa. Our results indicate that local heterogeneity did not significantly affect species richness; however, it had a notable impact on anuran abundance. We highlight the importance of heterogeneous habitats in supporting larger anuran populations and enhancing population stability. This study contributes to the understanding of biodiversity patterns and the primary environmental factors affecting anuran communities in Serra da Capivara National Park, offering insights to inform current and future conservation strategies.
Abundance, amphibians, biodiversity patterns, Caatinga, checklist, conservation unit, semiarid, species richness
Amphibians are among the most diverse vertebrate groups, with 8827 species registered worldwide (
Anurans play vital ecological roles, participating in various trophic interactions (
Among the states within the Caatinga biome, Piauí is one of the few to have an anuran checklist with 54 species registered (
Understanding the main drivers of anuran diversity is a complex task, as these animals are highly sensitive to environmental conditions (
This study was conducted in the Serra da Capivara National Park (SCNP), located in the state of Piauí, northeastern Brazil (Fig.
We conducted four expeditions, each lasting five consecutive days, from December 2023 to April 2024 in SNCP, totaling 20 sampling days. We used visual and auditory searches (
Environmental description of the 15 sampling points in the Serra da Capivara National Park, Piauí State, northeastern Brazil.
Sampling points | Geographic coordinates | Description |
---|---|---|
P1 | 8°38.92'S, 42°42.15'W | Artificial drinking fountain surrounded by shrubs and trees |
P2 | 8°38.93'S, 42°42.68'W | Artificial drinking fountain surrounded by shrubs and trees |
P3 | 8°45.97'S, 42°33.52'W | Temporary pond with shrub and tree vegetation inside and on the edge of the pond |
P4 | 8°48.07'S, 42°36.55'W | Temporary pond with shrub and tree vegetation inside and on the edge of the pond |
P5 | 8°51.72'S, 42°41.24'W | Rocky outcrop modified to accumulate water for longer, presence of thorny shrub and tree vegetation |
P6 | 8°51.94'S, 42°35.93'W | Artificial drinking fountain surrounded by shrubs and trees |
P7 | 8°51.75'S, 42°35.26'W | Modified passage that accumulates water surrounded by shrubs and trees |
P8 | 8°49.24'S, 42°33.54'W | Modified pond located inside the cave |
P9 | 8°49.85'S, 42°33.25'W | Modified passage that accumulates water surrounded by shrubs and trees |
P10 | 8°50.94'S, 42°33.92'W | Modified pond located inside the cave |
P11 | 8°48.62'S, 42°32.40'W | Artificial drinking fountain surrounded by shrubs and trees |
P12 | 8°47.94'S, 42°28.57'W | Temporary pond with shrub and tree vegetation inside and on the edge of the pond |
P13 | 8°47.05'S, 42°29.39'W | Modified passage that accumulates water surrounded by shrubs and trees |
P14 | 8°49.34'S, 42°31.89'W | Permanent reservoir with shrub and tree vegetation inside and on the edge of the pond |
P15 | 8°49.16'S, 42°31.65'W | Temporary pond with shrub and tree vegetation inside and on the edge of the pond |
We measured a set of nine abiotic and biotic variables at each of the 15 sampling points (Table
List of variables recorded at each sampling point within the Serra da Capivara National Park, Piauí State, northeastern Brazil, including unit, detailed nomenclature and method.
Variable name | Definition | Unit | Method |
---|---|---|---|
Margin type | Pond edge characteristic | Three categories: plan (1), inclined (2) or both (3) | Visual characterization |
Vegetation within the pond | Approximate percentual vegetation on pond surface | Four categories: No vegetation (0), < or = 20% (1), < or = 50% (2), > 50% (3) | Visual estimation |
Types of vegetation within the pond | Characteristics of the vegetation (herbaceous, shrubby and arboreal) present in the water body | Four categories: no vegetation (0), one type of vegetation (1), two types (2), three types (3) | Visual characterization |
Types of marginal vegetation | Characteristics of marginal vegetation (herbaceous, shrubby and arboreal) on the margin of the water body | Four categories: no vegetation (0), one type of vegetation (1), two types (2), three types (3) | Visual characterization |
Pond localization | Characteristics of where the pond is located | Two categories: inside the cave (1), outside the cave (2) | Visual characterization |
Pond number | Number of ponds present within a 200m radius of the largest pond | Three categories: one (1), two (2), more than two (3) | Visual characterization |
Pond size | Surface area of the pond (m²) when full (if there is more than one pond, it will be considered the largest) | Four categories: < or = 3 m² (1), < or = 5 m² (2), < or = 10 m² (3), > 10 m² (4) | Measured using length, width and shape |
Maximum pond depth | Maximum depth (m) when full (if there is more than one pond, it will be considered the largest) | Three categories: < or = 1 m (1), < or = 2 m (2), > 2 m (3) | Measured at deepest point of water body. |
Pond type | Characterized based on the level of anthropic action | artificial (1), modified (2), natural (3) | Visual characterization |
We used sample-based accumulation curves (
Considering the SCNP is a UC located in the Caatinga biome, we compared the diversity of anurans registered in the present study with 13 other localities within this biome characterized by the Caatinga sensu stricto as the predominant plant physiognomy: Picos municipality (PICOS), Piauí State (
We first tested the normality of the variables using the SHAPIRO-WILK test and log-transformed those that did not meet normality assumptions (Shapiro-Wilk p < 0.05), which applied only to species abundance data. To detect collinearity among the variables, we calculated the Variance Inflation Factors (VIF) and excluded any variable with a VIF ≥ 10 (
We then used Akaike’s Information Criterion with second-order bias correction for small samples (AICc) to compare models for each response variable alone or in combination (
We recorded a total of 551 individuals representing 16 anuran species across five families: Bufonidae (N = 2), Hylidae (N = 4), Leptodactylidae (N = 8), Microhylidae (N = 1), and Phyllomedusidae (N = 1) (Table
Anurans registered in the Serra da Capivara National Park, Piauí State, northeastern Brazil: a Rhinella diptycha b Rhinella granulosa c Corythomantis greeningi d Dendropsophus soaresi e Scinax x-signatus f Trachycephalus cf. nigromaculatus g Leptodactylus fuscus h Leptodactylus macrosternum i Leptodactylus syphax j Leptodactylus troglodytes k Leptodactylus vastus l Physalaemus cicada m Physalaemus cuvieri n Pleurodema diplolister o Pithecopus gonzagai p Dermatonotus muelleri.
Anurans registered in the Serra da Capivara National Park, Piauí State, northeastern Brazil, including voucher, occurrence in the SCNP, and distribution in the Brazilian biomes.
Taxa | Voucher | Occurrence | Biome |
---|---|---|---|
BUFONIDAE | |||
Rhinella diptycha (Cope, 1862) | CBPII 534 | 1–3, 5–11, 13–15 | WD |
Rhinella granulosa (Spix, 1824) | CBPII 536 | 2, 3, 5, 6, 8–12, 14, 15 | WD |
HYLIDAE | |||
Corythomantis greeningi Boulenger, 1896 | CBPII 567 | 1, 6, 9, 10, 12 | AT, CA, CE |
Dendropsophus soaresi (Caramaschi & Jim, 1983) | CBPII 537 | 1–7, 9, 10 | AT, CA, CE |
Scinax x-signatus (Spix, 1824) | CBPII 528 | 1–6, 9–12, 14, 15 | WD |
Trachycephalus cf. nigromaculatus Tschudi, 1838 | CBPII 558 | 3 | AT, CA, CE |
LEPTODACTYLIDAE | |||
Leptodactylus fuscus (Schneider, 1799) | CBPII 590 | 10, 12, 14, 15 | WD |
Leptodactylus macrosternum Miranda-Ribeiro, 1926 | CBPII 583 | 10, 11, 13–15 | WD |
Leptodactylus syphax Bokermann, 1969 | CBPII 569 | 2, 6, 8–11, 13 | WD |
Leptodactylus troglodytes Lutz, 1926 | CBPII 526 | 1–15 | WD |
Leptodactylus vastus Lutz, 1930 | CBPII 587 | 1, 3–11, 13–15 | WD |
Physalaemus cicada Bokermann, 1966 | CBPII 585 | 11, 12, 15 | – |
Physalaemus cuvieri Fitzinger, 1826 | CBPII 531 | 1, 3–9, 13, 14, 15 | WD |
Pleurodema diplolister (Peters, 1870) | CBPII 769 | 11 | AT, CA, CE |
MICROHYLIDAE | |||
Dermatonotus muelleri (Boettger, 1885) | CBPII 555 | 3, 4, 6, 7, 9, 11, 12, 15 | WD |
PHYLLOMEDUSIDAE | |||
Pithecopus gonzagai Andrade, Haga, Ferreira, Recco-Pimentel, Toledo & Bruschi, 2020 | CBPII 548 | 1–6, 9–14 | CA, CE |
The species accumulation curve indicated a strong tendency toward stabilization (Fig.
We observed the formation of four clusters regarding the anuran composition of the Caatinga sensu stricto areas analyzed: the first one was formed by São João do Cariri and the Cabaceiras municipalities, Paraíba State, and the Itapipoca municipality, Ceará State. The second one is the largest cluster with seven areas within Ceará, Pernambuco, Piauí, and Rio Grande do Norte states. The anuran composition of the SCNP was more similar to those registered in the Catimbau National Park, Pernambuco State, and Nordestina municipality, Bahia State. The Raso da Catarina Ecological Station was isolated in the cluster analysis (Fig.
Regarding the variables analyzed, we found that local habitat heterogeneity did not significantly influence anuran richness in SCNP (P > 0.05); however, it played a crucial role in explaining anuran abundance. Specifically, significant variables included margins profile (z-value = 2.907, P = 0.003), types of marginal vegetation (z-value = 2.304, P = 0.021), percentage of vegetation cover within ponds (z-value = 4.070, P < 0.001), number of ponds at the sampling point (z-value = 5.600, P < 0.001), depth of the largest pond at the sampling point (z-value = 2.991, P = 0.002), and type of ponds at the sampling point (z-value = -3.211, P = 0.001; Suppl. material
We identified 16 anuran species in the Serra da Capivara National Park (SCNP), which accounts for approximately 30% of the anurans known from Piauí State (
When focusing solely on conservation units in Piauí State, the number of species in SCNP is lower than in other protected areas, such as Uruçuí–Una Ecological Station (
In terms of anuran species composition, most species identified are considered widespread across Brazilian biomes, including Rhinella diptycha, Scinax x-signatus, Leptodactylus fuscus, L. macrosternum, L. syphax, L. vastus, Physalaemus cuvieri, and Dermatonotus muelleri (
Overall, the families Leptodactylidae and Hylidae exhibited the highest diversity within the SCNP, a pattern that is frequently observed in the Neotropical region (
We found that anuran richness in the Serra da Capivara National Park (SCNP) was not significantly influenced by local heterogeneity, regardless of whether the sampling ponds were natural, modified, or artificial. While some studies have similarly reported a lack of support for this relationship (e.g.,
In contrast, we observed that sampling points with a higher percentage of vegetation within the ponds and a greater diversity of marginal vegetation tended to support greater anuran abundance. Additionally, the characteristics of the ponds played a significant role in influencing anuran abundance. Other studies have similarly highlighted the impact of vegetation and pond characteristics on anuran populations (e.g.,
This study enhances the understanding of biodiversity in the Serra da Capivara National Park by presenting an updated anuran checklist, which may inform current and future conservation strategies. Furthermore, we found that local heterogeneity influences population sizes, emphasizing the importance of heterogeneous environments in promoting stable anuran populations. Notably, artificial drinking fountains designed to support vertebrate populations during the dry season also contribute to anuran diversity, as some species utilize these structures for reproduction and establish nearby populations. Although our study is pioneering in exploring the primary drivers of anuran diversity in the SCNP, further research is essential to deepen our understanding of the ecological processes shaping these anuran communities.
We are grateful to ICMBio for the collection license (Permit: ICMBio 87498-1). We thank the Federal Institute of Piauí for the logistical support in the field and for the use of the laboratory.
The authors have declared that no competing interests exist.
This study was approved by the Ethics Committee on the Use of Animals of the Instituto Federal do Piauí (CEUA/IFPI – 02/2024).
We are grateful to CNPq/CAPES/FAPEPI for financial support (Finance Code 001; 150013/2023-0). NLAR thanks CAPES for granting a research grant (8888.7827305/2023-00) and Programa de Pós-graduação em Ecologia e Conservação da Biodiversidade, da Universidade Estadual de Santa Cruz (PPGECB UESC) for financial support. MS acknowledges funding by CNPq through a research scholarship (309365/2019-8).
Conceptualization: KCA, EBA, NLRA. Data curation: EBA. Formal analysis: NLRA, MS, EBA, KCA. Investigation: KCA, NLRA, MS. Methodology: KCA, NLRA. Project administration: EBA, MS. Resources: MS. Supervision: EBA, MS. Visualization: EBA. Writing – original draft: NLRA, KCA. Writing – review and editing: EBA, KCA, MS.
Kássio de Castro Araújo https://orcid.org/0000-0003-4091-8521
Nayla Letícia Rodrigues Assunção https://orcid.org/0000-0002-6847-1269
Mirco Solé https://orcid.org/0000-0001-7881-6227
Etielle Barroso de Andrade https://orcid.org/0000-0002-5030-1675
All of the data that support the findings of this study are available in the main text or Supplementary Information.
Supplementary data
Data type: docx