Faunal diversity of an insular crepuscular cave of Goa, India

Pratiksha Sail,Manoj Ramakant Borkar,Archana Pal,Ismat Shaikh

doi:10.11609/jott.6628.13.2.17630-17638

Abstract

This study is the first attempt to document troglofaunal diversity of crepuscular cave ecosystem from the state of Goa. Twelve faunal species (seven invertebrates and five vertebrates) have been documented from an insular crepuscular cave which measures 18.62m in floor length and shows a transition of light and hygrothermal profile between its entrance and dead end. Absence of primary producers, thermal constancy, high humidity, poor ventilation, and competitive exclusion due to limited food resources restricts the faunal diversity of this cave; though trophic linkages are interesting yet speculative, as is typical of subterranean ecosystem. Among the macro-invertebrates, cavernicolous Whip Spider is a significant species here; whereas the important vertebrates encountered are the Fungoid frog and the Indian Cricket frog, besides roosts of the Rufous Horseshoe bat. Eco-energetic subsidy, possibly offered by crickets and bats that regularly feed outside this oligotrophic cave ecosystem is discussed. The need to document the unique and vulnerable troglofauna of this sensitive ecosystem from the conservation perspective is highlighted.

Highlights

Caves are natural or man-made subterranean cavities that may be formed in the face of a cliff or a hillside
The limited organization of a cave ecosystem has been attributed to permanent darkness and competitive exclusion due to resource scarcity (Fernandes et al 2016)
Despite a relatively hostile cavernous environment characterized by diffuse or complete absence of light, constant temperature and high humidity, poor air circulation and severely constrained food supplies; caves do support and sustain a unique assemblage of biota, whose density is lower than epigean habitats (Mitchell et al 1977; Parzefall 1983)

Summary

Introduction

Caves are natural or man-made subterranean cavities that may be formed in the face of a cliff or a hillside. Their speleogenesis is attributed to various geologic processes; inclusive of a combination of chemical processes, erosion by water, tectonic forces, microorganisms, pressure and atmospheric influences (Ford & Williams 2007). Cave as an ecosystem has its unique features characterized by gradients of darkness, narrow range of temperature differences and high humidity with limited air currents as some of its abiotic factors. These features make the cave ecosystem unique and the study of its biota fascinating (Biswas 2009). Species colonise caves for various reasons for at least part of their life cycles for temporary shelter or due to low predation pressure and easy availability of prey (Biswas 2009)

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