Distribution of Pluchea dioscoridis plant community types in relation to the combined effect of soil and climate

Abstract

Studying the factors affecting plants distribution is important for designing a sound management under both current and expected climate change. The present study aims to assess the distribution of Pluchea dioscoridis (L.) DC. and the main environmental factors affecting it along a gradient of aridity. Twenty-two stands distributed latitudinal were surveyed where vegetation was investigated and soil samples were collected and analyzed. A significant difference between soil characteristics at the studied stands was detected. Sixty-two species (34 perennials and 28 annuals) belong to thirty-one families were identified with Asteraceae, Chenopodiaceae and Poaceae as the most represented families. Therophytes followed by Chamaephytes are the highest recorded life forms. The highest represented chorotype elements are the Mediterranean (37.3%) followed by Saharo-Sindian (35.6%). TWINSPAN analysis identified three vegetation assemblages. Each one is connected with at least one main climate region and associated species. The Canonical Correspondence Analysis (CCA) showed that water content, chlorides, NaCl, potassium, sodium, calcium, clay and organic matter are the most effective edaphic factors, while precipitation, relative humidity, dew point, temperature, minimum and maximum temperature are the most effective climatic factors on P. dioscoridis distribution. In conclusion, the results revealed that P. dioscoridis able to survive under a wide range of edaphic and climatic conditions. Its distribution is mainly affected positively by water-related and negatively by salinity factors. So, it is expected that distribtution of P. dioscoridis would be affected by any increase in aridity under the anticipated climate change.