Revista de Biología Tropical, ISSN: 2215-2075, Vol. 72: e53860, enero-diciembre 2024 (Publicado Ene. 29, 2024)

Environmental sympatry through time: spatio-temporal distribution

and conservation status of two sympatric anuran species

(Leptodactylidae) in South America

Rebeca Acosta1; https://orcid.org/0000-0002-9052-3248

Facundo Alvarez*2; https://orcid.org/0000-0002-7095-9570

Betto Figueira3; https://orcid.org/0000-0001-6892-9922

Sofia Castro Cavicchini1; https://orcid.org/0000-0003-0280-9981

Rolando Vera1; https://orcid.org/0000-0003-3072-8740

Daryl D. Cruz4; https://orcid.org/0000-0002-7714-2459

Alejandro Nuñez1; https://orcid.org/0000-0003-4316-9423

1. Consejo de Investigación, Universidad Nacional de Salta, Salta, Argentina; normarebecaacosta@gmail.com;

soficastro2594@gmail.com; rolandovera824@gmail.com; alenunez.1964@gmail.com

2. Programa de Pós-graduação em Ecologia e Conservação, Campus Nova Xavantina, Nova Xavantina, Universidade do

Estado de Mato Grosso, Mato Grosso, Brasil; facualva87@gmail.com (*Correspondence)

3. Laboratório de Biologia Celular e Helmintologia, Instituto de Ciências Biológicas, Universidade Federal do Pará,

Belém, Pará, Brasil; herpetologostm@gmail.com

4. Centro de Investigación en Biodiversidad y Conservación, Universidad Autónoma del Estado de Morelos, México;

daryldavidcf@gmail.com

Received 25-I-2023. Corrected 07-VIII-2023. Accepted 18-I-2024.

ABSTRACT

Introduction: Leptodactylus latinasus and Physalaemus cuqui are sympatric anuran species with similar envi-

ronmental requirements and contrasting reproductive modes. Climatic configuration determines distribution

patterns and promotes sympatry of environmental niches, but specificity/selectivity determines the success of

reproductive modes. Species distribution models (SDM) are a valuable tool to predict spatio-temporal distribu-

tions based on the extrapolation of environmental predictors.

Objectives: To determine the spatio-temporal distribution of environmental niches and assess whether the

protected areas of the World Database of Protected Areas (WDPA) allow the conservation of these species in the

current scenario and future.

Methods: We applied different algorithms to predict the distribution and spatio-temporal overlap of environ-

mental niches of L. latinasus and P. c u q u i within South America in the last glacial maximum (LGM), middle-

Holocene, current and future scenarios. We assess the conservation status of both species with the WDPA

conservation units.

Results: All applied algorithms showed high performance for both species ( TSS = 0.87, AUC = 0.95). The L. lati-

nasus predictions showed wide environmental niches from LGM to the current scenario (49 % stable niches, 37 %

gained niches, and 13 % lost niches), suggesting historical fidelity to stable climatic-environmental regions. In the

current-future transition, L. latinasus would increase the number of stable (70 %) and lost (20 %) niches, suggest-

ing fidelity to lowland regions and a possible trend toward microendemism. P. cu q ui loses environmental niches

from the LGM to the current scenario (25 %) and in the current-future transition (63 %), increasing the envi-

ronmental sympathy between both species; 31 % spatial overlap in the current scenario and 70 % in the future.

https://doi.org/10.15517/rev.biol.trop..v72i1.53860

CONSERVATION

2Revista de Biología Tropical, ISSN: 2215-2075 Vol. 72: e53860, enero-diciembre 2024 (Publicado Ene. 29, 2024)

INTRODUCTION

Climate change, driven by anthropogenic

actions, has the potential to modify the distri-

bution patterns of biodiversity and the compo-

sition of ecological communities (Bellard et al.,

2012; Kohler et al., 2010; Menéndez-Guerrero

et al., 2020). Its effects include alterations in the

spatio-temporal distribution patterns, increases

in the probability of extinction, and declines

in species richness (Clavel et al., 2011; Pounds

et al., 2006; Stuart et al., 2004; Wake, 1991).

Therefore, climate change could alter the beta

diversity of anurans at the landscape level;

declines in anuran species richness are pro-

jected, limiting ecosystem functions (Anderson

et al., 2011; Magurran et al., 2019; Menéndez-

Guerrero et al., 2020). Climate change favors the

turnover of specialist species, with geographi-

cally restricted distribution patterns, by gen-

eralist species with wide spatial distributions,

all without generating concomitant changes in

species richness (Anderson et al., 2011; Bellard

et al., 2012; Clavel et al., 2011; Magurran et al.,

Conclusion: Extreme drought events and rainfall variations, derived from climate change, suggest the loss of

environmental niches for these species that are not currently threatened but are not adequately protected by con-

servation units. The loss of environmental niches increases spatial sympatry which represents a new challenge for

anurans and the conservation of their populations.

Key words: species distribution models; environmental sympatry; niche overlap; climate change; Leptodactylus

latinasus; Physalaemus cuqui.

RESUMEN

Simpatría ambiental a través del tiempo: distribución espacio-temporal y estado de conservación de dos

especies de anuros simpátricos (Leptodactylidae) en América del Sur

Introducción: Leptodactylus latinasus y Physalaemus cuqui son especies de anuros simpátricos con requerimien-

tos ambientales similares y modos reproductivos contrastantes. La configuración climática determina los patrones

de distribución y promueve la simpatría de los nichos ambientales, pero la especificidad/selectividad determina el

éxito de los modos reproductivos. Los modelos de distribución de especies (MDE) son una herramienta valiosa

para predecir distribuciones espacio-temporales basadas en la extrapolación de predictores ambientales.

Objetivos: Determinar la distribución espacio-temporal de los nichos ambientales y evaluar si las áreas protegi-

das de la base de Datos Mundial de Áreas Protegidas (DMAP) permiten la conservación de estas especies en el

escenario actual y futuro.

Métodos: Aplicamos diferentes algoritmos para predecir la distribución y superposición espacio-temporal de

nichos ambientales de L. latinasus y P. cu qu i dentro de América del Sur en el último máximo glacial (UGM),

Holoceno medio, actual y futuro. Evaluamos el estado de conservación de ambas especies con las unidades de

conservación de la DMAP.

Resultados: Todos los algoritmos aplicados mostraron un alto rendimiento para ambas especies ( TSS = 0.87,

AUC = 0.95). Las predicciones de L. latinasus mostraron amplios nichos ambientales desde LGM hasta el esce-

nario actual (49 % de nichos estables, 37 % de nichos ganados y 13 % de nichos perdidos), sugiriendo fidelidad

histórica por regiones climático-ambientales estables. En la transición actual-futura L. latinasus incrementaría

la cantidad de nichos estables (70 %) y perdidos (20 %), sugiriendo fidelidad por regiones de tierras bajas y la

posible tendencia hacia el microendemismo. P. c u q u i pierde nichos ambientales desde el LGM al escenario actual

(25 %) y en la transición actual-futura (63 %), incrementando la simpatría ambiental entre ambas especies; 31 %

de superposición espacial en el escenario actual y 70 % en el futuro.

Conclusión: Los eventos de sequía extrema y las variaciones de precipitaciones, derivados del cambio climático,

sugieren la pérdida de nichos ambientales para estas especies, actualmente no se encuentran amenazadas, pero

no están adecuadamente protegidas por las unidades de conservación. La pérdida de nichos ambientales aumenta

la simpatría espacial que representa un nuevo desafío para estos anuros y la conservación de sus poblaciones.

Palabras clave: modelos de distribución de especies; simpatría ambiental; superposición de nicho; cambio climá-

tico; Leptodactylus latinasus; Physalaemus cuqui.

Revista de Biología Tropical, ISSN: 2215-2075, Vol. 72: e53860, enero-diciembre 2024 (Publicado Ene. 29, 2024)

2019). Modeling the spatio-temporal distribu-

tion patterns of species with different reproduc-

tive modes and climate dependencies will help

understand species-specific responses to global

warming, acting as a framework for the devel-

opment of conservation strategies.

The last glacial maximum (LGM) and

the middle-Holocene (MH) are synonyms of

climatic dynamics and environmental hetero-

geneity characterized by connection/discon-

nection processes between large tropical forests

(Kohler et al., 2010; Sobral-Souza et al., 2015).

These highly dynamic scenarios represented a

challenge for anuran biodiversity that experi-

enced variations in composition, abundance,

and spatio-temporal distribution patterns

(Pounds et al., 2006; Stuart et al., 2004; Wake,

1991). Although the tropical region exhibits

high abundance, richness, and endemism of

anurans, South America is the region where

this taxon is most threatened (Fouquet et al.,

2007; Menéndez-Guerrero et al., 2020; Stuart

et al., 2004; Stuart et al., 2008). Specifically, the

Neotropical region supports the greatest diver-

sity of anurans in the world, with approximately

3 000 registered species (Frost, 2022). Anurans

inhabit terrestrial and aquatic ecosystems, mak-

ing this taxon particularly sensitive to the

negative effects of climate change (Blaustein

et al., 2010; Bruzzi-Lion et al., 2019; Medina et

al., 2020; Menéndez-Guerrero et al., 2020). In

fact, in recent decades Neotropical amphibian

populations have decreased (Carey & Alexan-

der, 2003; Clavel et al., 2011; Pounds et al., 2006;

Stuart et al., 2004; Wake, 1991), with climate

change being a determining factor on differ-

ent spatio-temporal scales (Bellard et al., 2012;

Menéndez-Guerrero et al., 2020).

Niche models calculate the n-dimensional

hypervolume that defines the species’ ecologi-

cal niches from the environmental dimensions

of their conditions and resources (Hutchin-

son, 1957). Similarly, species distribution mod-

els (SDMs) allow inference of environmental

niches in past, current, and future climate

scenarios from the extrapolation of environ-

mental predictors, and the occurrence records

(Elith et al., 2006; Soberon, 2007). The family

Leptodactylidae is a broad taxon and in Argen-

tina is represented by 39 of the 232 species

described (Frost, 2022). Leptodactylus latina-

sus (Jiménez de la Espada, 1875), has a wide

geographic distribution including Argentina,

Bolivia, Paraguay, Uruguay, and southern Brazil

(Frost, 2022; Medina et al., 2020). Reproductive

activity of L. latinasus begins with the rainy

season (January-March) when temporary water

bodies are still dry (Ponssa et al., 2019). Like

many congeneric species, L. latinasus, lays its

eggs in underground chambers within foam

nests which prevent the larvae from drying

out from desiccation (Downie & Smith, 2003;

Ponssa & Barrionuevo, 2008). Larvaes hatch

inside the chamber and reach bodies of water

to complete their development (Bruzzi-Lion

et al., 2019; Ponssa & Barrionuevo, 2008). Phy-

salaemus cuqui (Lobo, 1993), is distributed in

Bolivia, Paraguay, and Argentina (Iglesias &

Natale, 2013). The reproductive activity of P.

cuqui depends strictly on rain: this species pres-

ents a marked seasonality in oviposition, which

occurs in floating foam nests inside temporary

water bodies (Ferrari & Vaira, 2001).

Although the environmental and climatic

requirements of both species are similar, the

reproductive modes have contrasting ecophysi-

ological constraints: How future climate change

could modify the spatial distribution patterns

of these species? We expect future climate

change to decrease the environmental niche

of both species, forcing the spatial distribution

patterns to stable climatic latitudes (Bruzzi-

Lion et al., 2019; Ferrari & Vaira, 2001; Medina

et al., 2020). The objectives of this research

were: 1) to determine the spatio-temporal dis-

tribution patterns of these sympatric species

with contrasting reproductive modes and, 2)

to evaluate whether the protected areas of the

World Database on Protected Areas (WDPA),

intended for the protection of biodiversity,

allow the conservation of these species in the

current scenario and in the future climatic

changes scenario.

4Revista de Biología Tropical, ISSN: 2215-2075 Vol. 72: e53860, enero-diciembre 2024 (Publicado Ene. 29, 2024)

MATERIALS AND METHODS

Study site: We delimited the study area

from the occurrence records of both species,

restricted to South America (Fig. 1). The topo-

graphic landscape is represented by floodplains

and highland ridges with air temperatures

ranging between 20-26 ºC and annual rain-

fall between 2 200 and 3 100 mm, classified

according to Köppen as Af and Am climates

(Peel et al., 2007). The study area exhibits high

spatial and environmental heterogeneity, incor-

porating different mosaics such as high-alti-

tude mountain ranges, floodplains, mangroves,

swamps, coastal regions, deserts, and savan-

nahs interconnected by hydrographic basins

and phytophysiognomic formations (Alvarez

et al., 2022).

Occurrence records: We selected the

Leptodactylus latinasus and Physalaemus

cuqui species, from the Leptodactylidae fam-

ily, because they are sympatric and although

both species present similar environmental

and climatic requirements, their reproduc-

tive modes respond differentially to climatic-

environmental conditions. The target species

are classified as “Least-concern”: L. latinasus

Fig. 1. Digital elevation model with the geographic distribution of Leptodactylus latinasus and Physalaemus cuqui in South

America. In grey scale, Kernel density map with areas of highest (white) and lowest (black) abundance density of records of

occurrence.