Impact of Fencing and Irrigation on Species Composition and Diversity of Desert Plant Communities in the United Arab Emirates

Abstract

AbstractGrazing and water are among the most important factors influencing community structure and productivity in natural rangelands. Little is known about the independent effects of grazing and water and their interaction on plant community structure and productivity in rangelands of the arid Arab Gulf deserts. Paired sampling plots were used to compare plant species composition, diversity and plant abundances and sizes inside and outside 14‐month irrigated and 30‐month non‐irrigated exclosures constructed during dry years on sandy dunes of the arid Dubai Desert Conservation Reserve. The results showed that the negative impacts of high grazing pressures on plant productivity (plant sizes and abundances) and diversity were stronger in the non‐irrigated sites. Both irrigation (IR) and protection (PR) enhanced plant diversity and productivity of the overgrazed degraded Dubai Desert Conservation Reserve. The combined effects of PR and IR resulted in the occurrence of a total of 22 species inside the irrigated exclosures; however, none of them appeared in the irrigated grazed sites. Eighteen palatable species occurred inside, but not outside, the irrigated exclosures. Chamaephytes, which are more sensitive to human and animal disturbances, recovered more than other life forms under PR and IR. Dipterygium glaucum showed a great potential to be used for restoration projects under water IR in the Arab Gulf deserts. It is concluded that grazing and water independently affected plant diversity and productivity, but the relative role of grazing is more important than that of water in conserving desert plants, especially the palatable ones. Copyright © 2016 John Wiley & Sons, Ltd.