Plant invasion represents one of the major drivers of global change worldwide. Invasive plant species modify invaded ecosystem’s structure and functioning by changing species composition and diversity, and by affecting nutrient cycles. A recent survey in Israel found that multiple planted populations of Prosopis (mostly P. juliflora) became invasive and currently invade 690 km2 of the Dead Sea shores, Negev desert, Jordan and Arava valleys. Despite increasing presence and high invasiveness of the Prosopis it’s impact on ecosystem and soil N and C cycles in Israeli ecosystems is currently unknown. To fill this knowledge gap, we studied effects of established Prosopis populations on the northern and southern shores of the Dead Sea on soil nitrogen (N) and carbon (C) cycles. We have compared gaseous emissions of nitrous and nitric oxides (N2O and NO) and C dioxide (CO2) during rewetting from soil under the canopy of P. juliflora with those from soil under canopy of native Red Thorn (Vachellia gerrardii) and to the bare soils outside canopies.
We found that overall dynamics of soil trace gases emissions during a rewetting event were similar under canopies of both invasive and native trees. However, the magnitudes of emissions were different, with soil under canopies of native Vachellia gerrardii emitting an order of magnitude more trace gases. Our results suggest that establishment of Prosopis trees slowing down N-cycling by higher uptake of soil N relative to the native trees. Biogeochemical drivers of the observed post-rewetting emissions, however requiring further research.
