The Blue Mountains upland peat swamps are a unique geomorphic system, situated on the sandstone escarpment just west of Sydney (NSW, Australia) and north and south along the eastern seaboard. The saturated sediments of the peat swamps form perched aquifers that are fed, in part, by local groundwater (Cowley et al. 2018). The swamps can be best described as shallow subterranean habitat (Culver and Pipan 2011) where surface water and groundwaters meet (Hose 2005; Tomlinson and Boulton 2010) creating a complex ecotone between terrestrial, aquatic, surface and subsurface systems. The swamps exhibit peat like conditions and both surface and groundwater in the swamps are acidic, with low concentrations of nutrients, conductivity, low temperature variability and high concentrations of organic matter.
This study investigated ecological functioning of swamp streams and groundwater impacted by varying urbanization effects through differences in hydrology, water quality, invertebrate communities and decomposition processes. We found that urban impacted swamps had altered hydrology, elevated electrical conductivity, alkalinity, pH and ammonium, exceeding those at unimpacted swamps. Leaf decay in streams and cotton strip decomposition in groundwater were elevation with increasing urban influence. There were also altered biodiversity and community structure of both surface and groundwater invertebrate community.
These urban influences pale into insignificance compared to the megafires that swept through the escarpment over the summer of 2019-2020. Sadly, those swamps closest to urban areas were more protected by fire protection services. Around 57% of THPSS were affected, with 72% of those severely affected (Fryirs et al. 2021). This raises larger questions related to climate change, to the role of peat swamps in storing carbon, threats and degradation worldwide and managing carbon emissions and sequestration into the future.