The changing biodiversity of Alabama Drosophila: important impacts of seasonal variation, urbanization, and invasive species.

Andrei Bombin,Laura K Reed

doi:10.1002/ece3.2452

Abstract

Global warming and anthropogenic disturbances significantly influence the biosphere, tremendously increasing species extinction rates. In Central Alabama, we analyzed Drosophilidae species composition change nearly 100 years after the previous survey. We found ten Drosophilid species that were not reported during the last major biodiversity studies, two of which are invasive pests. In addition, we analyzed the influence of seasonal environmental variables characteristic of the subtropical climate zone on Drosophila abundance and biodiversity. We found a significant correlation between temperature and abundance of total Drosophila as well as for six of the seven most represented species individually, with a maximum abundance at intermediate temperatures (18–26°C). In addition, temperature was positively correlated with biodiversity of Drosophila. Precipitation produced a significant effect on the abundance of five species of Drosophila, with different optima for each species, but did not affect overall biodiversity. We concluded that in the subtropical climate zone of Central Alabama, seasonal temperature and precipitation changes produce a significant effect on Drosophila abundance and biodiversity, while local land use also impacts fly abundance, contributing to an apparent shift in species composition over the last century. We expect global climate change and other anthropogenic factors to further impact Drosophila species composition in the subtropical climate zone into the future.

Highlights

In the face of global warming, we can see the influence of changes in the world’s climate on the biosphere
In contrast to abundance measures, we found no significant correlation between Drosophila biodiversity and land use
Given the growing level of urbanization, we expect that cosmopolitan species of Drosophila such as D. simulans, D. suzukii, and especially Z. indianus will become more abundant in Alabama and could establish themselves as dominant species in urban environments

Summary

| INTRODUCTION

In the face of global warming, we can see the influence of changes in the world’s climate on the biosphere. The abundance of Drosophila species is influenced primarily by precipitation in tropical regions (Dobzhansky & Pavan, 1950; Guruprasad et al, 2010; Srinath & Shivanna, 2014; Torres & Madi-Ravazzi, 2006), while in temperate climate regions, seasonal changes in abundance and biodiversity of Drosophila are better explained by temperature variation (da Mata et al, 2015; Patterson, 1943; Poppe, Valente, & Schmitz, 2013). Surveys of wild populations of cosmopolitan Drosophila are especially important as there are two known pest Drosophilids: Drosophila suzukii and Zaprionus indianus Both of these pest species are polyphagous and are very efficient in colonizing new types of environments (Burrack, Smith, Pfeiffer, Koeher, & Laforest, 2012; Commar et al, 2012). We hypothesized that abundance of cosmopolitan Drosophila species would be higher in urban settings than in industrial or minimally disturbed rural environments

| MATERIALS AND METHODS

Findings

| DISCUSSION

| CONCLUSION