Limiting the spread and impacts of invasive alien species (IAS) on biodiversity and ecosystems has become a goal of global, regional and national biodiversity policies. Evidence based management of IAS requires support by risk assessments, which are often based on expert judgment. We developed a tool to prioritize potentially new IAS based on their ecological risks, socio-economic impact and feasibility of management using multidisciplinary expert panels.

Lessons learned from rapid environmental risk assessments for prioritization of alien species using expert panels

Worldwide, coastal freshwater wetlands arefacingsalinizationat anincreasingrate duetolarge-scaleland use change, freshwater extraction, climate-drivensea level rise, droughts and land subsidence. Although itis known that increased surface water salinity doesinfluence wetland functioning, effects on nutrientdynamics reported in literature are contradictory andevidence from controlled, long-term field experiments isscarce. We therefore tested the effects of 4 levels ofincreased surface water salinity, from oligohaline tomesohaline conditions (0.9, 2.25, 4.5, 9 PSU), onbiogeochemical and physicochemical processes in thesediment of a formerly brackish freshwater wetland.

Salinization lowers nutrient availability in formerlybrackish freshwater wetlands; unexpected resultsfrom a long-term field experiment

Mires and peatlands in general are heavilyinfluenced by anthropogenic stressors like acidification,eutrophication, desiccation and fragmentation.Groundwater-fed mires are, in contrast to rainwater-fedmires, often well protected against desiccation due toconstant groundwater discharge. Groundwater-fedmires can however be influenced by groundwater pol-lution such as groundwater nitrate enrichment, a threatwhich has received minor attention in literature. Thepresent case study demonstrates how groundwater ni-trate enrichment can affect the biogeochemical function-ing and vegetation composition of groundwater-fedmires through direct nitrogen enrichment and indirectnitrate-induced sulphate mobilisation from geologicaldeposits.

Effects of Groundwater Nitrate and Sulphate Enrichmenton Groundwater-Fed Mires: a Case Study