Predation risk is a function of seasonality rather than habitat complexity in a tropical semiarid forest

Anthony Santana Ferreira,Renato Gomes Faria

doi:10.1038/s41598-021-96216-8

Anthony Santana Ferreira, Renato Gomes Faria

Open Access

https://doi.org/10.1038/s41598-021-96216-8

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Abstract

Predator–prey dynamics are some of the most important species’ interactions in the natural structuring of communities, and are among the more complex ecological processes studied by ecologists. We measured predation risk using artificial lizard replicas to test two competing hypotheses regarding predation pressure in semi-arid environments: (1) predation risk is dependent on the habitat structural complexity; and (2) predation risk is dependent on seasonality. We placed 960 lizard replicas along three sites with different physical structures and in both dry and rainy seasons for seven consecutive days in a caatinga area in northeastern Brazil at Grota do Angico Natural Monument (GANM). Birds were responsible for the majority of attacks and more frequently on artificial lizards placed in trees. Attacks focused on the most vulnerable areas of the body (head and torso), proving that were perceived by predators as true prey items. We found that predation risk is not dependent on the habitat structural complexity, but rather dependent on the caatinga seasonality, with the overall attack rate being 19% higher in the dry season. Our study suggests that potential predation risk is highly context-dependent and that seasonality consistently drives of trophic interactions strength in the caatinga, an important ecological finding that could contribute to better understanding the complex evolution of predator–prey interactions within communities of animals living in different habitats.

Highlights

Predator–prey dynamics are some of the most important species’ interactions in the natural structuring of communities, and are among the more complex ecological processes studied by ecologists
The primary goal was to empirically test two hypotheses regarding predation risk: (1) is predation risk dependent on the habitat structural complexity, i.e., does predation risk increase in less complex habitats; or (2) is predation risk dependent on seasonality, i.e., does predation risk increase in the dry season due the seasonally deciduous nature of caatinga vegetation that results in a loss of protective cover for potential prey? We further investigated predator attack patterns with respect to potential predators and the location of attacks on a lizard’s body
Our results showed that predation risk on lizards was not directly related to structural differences between habitats

Summary

Introduction

Predator–prey dynamics are some of the most important species’ interactions in the natural structuring of communities, and are among the more complex ecological processes studied by ecologists. To better understand this issue, we used attack rates on soft replicas as surrogates for lizards (sentinel prey) to directly quantify predation risk and examine the relative role of habitat structural complexity and interseasonality variation in determining predation risk in three different habitats in the Grota do Angico Natural Monument (GANM) in the Caatinga of northwest Sergipe, Brazil.

Results

Conclusion