Anthropogenic nitrogen pollution impacts saltmarsh resilience with inhibition of seedling establishment and population dispersal.

Saltmarsh, a prominent buffer ecosystem, has been identified as an important sink for nitrogen (N) pollutants from marine- and land-based anthropogenic activities. However, how the enriched anthropogenic N impacts saltmarsh sustainability has been neglected due to limited understanding of marsh resilience based on seedling establishment and population dispersal under anthropogenic N inputs. This study combined mesocosm experiments and model simulations to quantify the effects of increased anthropogenic N on the seedling-based vegetation expansion of Spartina alterniflora. The results indicated that seedling survivals, growth rates, and morphological indicators were inhibited by 20.08 %, 37.14 %, and > 35.56 %, respectively, under 1.5 gN/kg anthropogenic N. The sensitivity rate of vegetation expansion was increased by 70 % with 1 gN/kg increased N concentration under the scenario of low seedling density (< 15 m/yr). These findings revealed an important unidentified weakness of the marsh development process to anthropogenic N inputs. Finally, we highlighted the importance of appropriate protection measures to control nutrient pollution in salt marshes. Our study provides new insights for enhancing the resilience and sustainability of saltmarsh ecosystems.

Experimental evidence supports the ability of spotted lanternfly to hitchhike on vehicle exteriors as a mechanism for anthropogenic dispersal.

Historically, anecdotal observations support the likelihood of human-assisted invasive insect dispersal to new environments. No previous studies have investigated the ability of insects to remain attached to moving vehicles; however, such information is critical for prioritizing research, mitigation activities and understanding anthropogenic effects on biotic communities. Lycorma delicatula (White), spotted lanternfly (SLF), an invasive insect whose range is currently expanding throughout the United States, is commonly observed in urban settings and near transportation hubs. We developed a novel method to test SLF's ability to remain on vehicle surfaces including bonnet, nose wing, windscreen, wipers and scuttle panel using laminar wind flow from 0 to 100 ± 5 km h-1. We found all mobile life stages (nymphs and adults) could remain on the vehicle up to 100 km h-1. First instar nymphs and early season adults remained attached at significantly higher wind speeds than other stages. A brief acclimatization period prior to wind delivery increased attachment duration for all life stages except later season adults. The importance of outliers in the success of invasive species is well established. Given these results, any hitchhiking SLF could potentially establish incipient populations. This methodology will be beneficial for exploring human-assisted dispersal of other invasive arthropods.