Impact of climate change on vegetative species diversity in Masvingo Province, Zimbabwe

Abstract

Vegetative species diversity is under threat from environmental pressures, particularly climate change. As the impacts of climate change vary from place to place, response of vegetative species diversity to a changing climate also vary depending on geographical location. The response of vegetative species diversity under dry conditions in Zimbabwe is not well known. This study assessed the impact of climate change on vegetative species diversity under semiarid conditions of Masvingo province in Zimbabwe. This was achieved by determining climate change trends over a period of forty years (1974-2014), and examining the relationship between vegetative species diversity and spatially interpolated climate data. The absence of historical diversity data prompted the use of remote sensing to enable the assessment of spatial and temporal changes. Thus, the Normalised difference vegetation index (NDVI) was used to assess vegetative species diversity changes after establishing a positive relationship between species diversity and NDVI. The mixed methods research design was used as the strategy of inquiry. The non-aligned block sampling design was used as the sampling framework from which 198 sampling points were identified. Meteorological data obtained from Zimbabwe Meteorological Services Department (ZMSD) and the National Climate Data Centre (NCDC) were used for climate change analysis. Data collected through image analysis, direct observations, questionnaire surveys and interviews were used to assess the impact of climate change on vegetative species diversity. Results indicate that all temperature and precipitation variables have significant (p<0.05) trends over the period under study. However, the trend for seasonal total precipitation was not significant but declining. The significant trends indicate that climate change occurred over the period under study. 93% of the respondents confirmed having experienced the climate change phenomenon. Results also show a significant relationship between climate elements (precipitation and temperature) and vegetative species diversity represented by Shannon Weaver Index (H). More so, there is a positive relationship between NDVI and H. Vegetative species diversity represented by NDVI decreased over the period under review. The results indicate that climate change has contributed to the decrease of vegetative species diversity in Masvingo province, thus it is a force behind many other factors contributing to biodiversity loss.