Precipitation mediates termite functional diversity and dominance in southern Africa

Brianna M. Lind,Niall Hanan,Vivienne M. Uys,Paul Eggleton

doi:10.38201/btha.abc.v52.i1.3

Abstract

Background: Termites are important ecosystem engineers in the tropics and sub-tropics, so understanding their diversity, particularly their functional diversity, across biogeographical scales is important for understanding where they alter theenvironment and deliver ecological services. Feeding groups combine phylogeneticand dietary information about termites into ecologically significant functional categories.Objectives: To characterise termite feeding group prevalence, distribution and diversity in southern Africa and assess the effect of precipitation on termite diversity and assemblage composition.Method: Termite genus and species-level occurrence data were acquired from the South African Termite Database and classified into one of five feeding groups. We evaluated the prevalence of each feeding group and assessed species and feeding group richness and dominance. Linear regressions were performed to determine the relationship between 1) species richness and precipitation; and 2) feeding group richness and precipitation.Results: We find that southern Africa 1) is dominated by FG-IIw (feeding group – II, wood feeding) termites; 2) is occupied by multiple feeding groups across the entirety of the rainfall gradient; and that precipitation 3) influences feeding group species diversity variably; and 4) causes notable shifts in termite community structure.Conclusion: Our results indicate that termites likely make substantial contributionsto plant material decomposition across southern Africa and that while shifts in feeding group dominance are associated with rainfall gradients, the services unique to individual feeding groups are not isolated to certain regions, but ratherare widespread regardless of the amount of precipitation received.

Highlights

Termites are important ecosystem engineers (Lee & Wood 1971; Jones et al 1994; Sileshi et al 2010; Jouquet et al 2011; Ashton et al 2019), so understanding the species and functional diversity across biogeographic scales is important for understanding how and where they alter the environment and deliver services
The major findings of this study are that southern Africa: 1) is dominated by FG-IIw termites; and 2) is occupied by multiple FGs across the entire rainfall gradient; and that 3) precipitation influences feeding group richness variably, with some FGs increasing with rainfall, while others decrease in prevalence; and 4) patterns in FG variability with rainfall cause notable shifts in assemblage with possible implications for the role of termites in carbon and nutrient cycles
Extensive and continuous survey efforts of termites globally, our analysis is restricted in the sense that it excludes a notable portion of southern Africa (Botswana and Mozambique) and the areas of highest precipitation in southern Africa (Mozambique)

Summary

Introduction

Termites are important ecosystem engineers (Lee & Wood 1971; Jones et al 1994; Sileshi et al 2010; Jouquet et al 2011; Ashton et al 2019), so understanding the species and functional diversity across biogeographic scales is important for understanding how and where they alter the environment and deliver services. FG-III termites consume partially decayed organic matter and FG-IV termites consume compounds stabilised in soils (Jouquet et al 2011), indicating that in areas where these feeding groups are found, soil organic matter dynamics will be influenced. Scaling up these insights helps to clarify the presence or absence of broad scale processes across large geographical areas. Feeding groups combine phylogenetic and dietary information about termites into ecologically significant functional categories

Objectives

Methods

Results

Discussion

Conclusion