The Impact of Terrestrial Oil Pollution on Parasitoid Wasps Associated With Vachellia (Fabales: Fabaceae) Trees in a Desert Ecosystem, Israel

Abstract

Oil is a major pollutant of the environment, and terrestrial oil spills frequently occur in desert areas. Although arthropods account for a large share of animal diversity, the effect of oil pollution on this group is rarely documented. We evaluated the effects of oil pollution on parasitoid wasps associated with Vachellia (formerly Acacia) tortilis (Forssk.) and Vachellia raddiana (Savi) trees in a hyper-arid desert that was affected by two major oil spills (in 1975 and 2014). We sampled the parasitoid populations between 2016 and 2018 in three sampling sites and compared their abundance, diversity, and community composition between oil-polluted and unpolluted trees. Parasitoid abundance in oil-polluted trees was lower in one of the sites affected by the recent oil spill, but not in the site affected by the 1975 oil spill. Oil-polluted trees supported lower parasitoid diversity than unpolluted trees in some sampling site/year combinations; however, such negative effects were inconsistent and pollution explained a small proportion of the variation in parasitoid community composition. Our results indicate that oil pollution may negatively affect parasitoid abundances and diversity, although the magnitude of the effect depends on the tree species, sampling site, and the time since the oil spill.

Invertebrate and vertebrate predation rates in a hyperarid ecosystem following an oil spill

“…We find it more likely that higher water availability to the polluted trees due to their central location in the streambed, rather than direct effects of the oil pollution, accounted for this pattern. Although our hypothesis that oil pollution would reduce the activity both invertebrate and vertebrate predators was not confirmed, oil pollution is a major threat to this ecosystem: It was shown to change the soil microbial community (Girsowicz et al., 2018 ) and parasitoid abundance (Möller et al., 2020 ), as well as to reduce Vachellia seed germination (Tran et al., 2018 ), seedling recruitment (Nothers et al., 2017 ), and to modify the tree metabolism (Ferrante et al., 2021 ).…”

“…This is because several agents of mortality for caterpillars are probably underestimated by this method. For example, parasitoid wasps, which are diverse in this ecosystem (Möller et al., 2020 ), mostly rely on chemical cues (Godfray, 1994 ) and are unlikely to attack artificial prey. Also, spiders, which are important predators in deserts, mostly attack moving prey (Persons & Uetz, 1997 ).…”

“…In this area, two large oil spills occurred in 1975 and 2014, during which around 10,000 m 3 and 5,000 m 3 of crude oil, respectively, leaked into the area jeopardizing the entire ecosystem (Golan et al, 2016). Oil pollution has been shown to affect the metabolism, recruitment, and germination of keystone tree species in this area (Ferrante et al, 2021;Golan et al, 2016;Nothers et al, 2017) and may negatively affect insect biodiversity (Möller et al, 2020) with potential cascading effects on biotic interactions. We focused our study on predation, a fundamental ecosystem function (Hairston et al, 1960).…”

Oil Pollution Affects the Central Metabolism of Keystone Vachellia (Acacia) Trees

“…Two adjacent study sites affected by the 2014 oil spill were selected: the first (Evrona North) where both V. raddiana and V. tortilis occur, and the second (Evrona South) with V. tortilis only. See Möller et al [41] for additional details on the study sites. From 24 to 27 September 2017, 10 V. raddiana trees that were not in the main route of the oil spill (i.e., unpolluted soil) and eight trees that were directly exposed to the oil (i.e., growing in oil-polluted soil) were selected.…”

Recent advances in Shrimp aquaculture wastewater management

“…As a result of these staggering figures of death resulting from water pollution, many conventional methods have been advanced for shrimp aquaculture wastewater management. Some of these include coagulation, advanced oxidation process, membrane filtration process, adsorption, dialysis, phytocatalytic degradation and biological methods (Li et al, 2019;M€ oller et al, 2020). These methods have been proven effective in the removal of toxic substances causing pollution in shrimp aquaculture and other wastewater generating ventures.…”