Conservation Need for a Plant Species with Extremely Small Populations Linked to Ephemeral Streams in Adverse Desert Environments

Abstract

Many thousands of tree species are declining in the world, for which conservation actions are urgent. This dramatic situation is particularly evident for trees closely related to freshwater ecosystems, considered the environments most threatened by global change. In extremely arid environments such as deserts, where the few plant species present are able to survive by exploiting the little water available, the situation is extremely critical. A representative case is Vachellia gerrardii subsp. negevensis, a tree with a wide distribution range but locally restricted to small and isolated populations. Knowledge about this tree is incomplete in Iraq and, to fill this gap, several surveys were conducted in the Al-Najaf desert over three years (2019–2021). In each locality where this species was found, several ecological and population parameters were recorded. Our results indicate that Vachellia gerrardii subsp. negevensis was restricted to a single population, fragmented into five subpopulations confined in extremely peculiar ecological niches. Several threats related to anthropogenic activities and climate change affect the population, causing a significant reduction in the population size combined with a continuous decline in habitat quality and number of mature plants. Despite this critical situation, there are no conservation measures for this species. The establishment of a national preserve or part would be important and constitutes the fundamental prerequisite for the conservation of multiple species.