Assessing anthropogenic impact on boreal lakes with historical fish species distribution data and hydrogeochemical modeling

Abstract

Quantifying the effects of human activity on the natural environment is dependent on credible estimates of reference conditions to define the state of the environment before the onset of adverse human impacts. In Europe, emission controls that aimed at restoring ecological status were based on hindcasts from process-based models or paleolimnological reconstructions. For instance, 1860 is used in Europe as the target for restoration from acidification concerning biological and chemical parameters. A more practical problem is that the historical states of ecosystems and their function cannot be observed directly. Therefore, we (i) compare estimates of acidification based on long-term observations of roach (Rutilus rutilus) populations with hindcast pH from the hydrogeochemical model MAGIC; (ii) discuss policy implications and possible scope for use of long-term archival data for assessing human impacts on the natural environment and (iii) present a novel conceptual model for interpreting the importance of physico-chemical and ecological deviations from reference conditions. Of the 85 lakes studied, 78 were coherently classified by both methods. In 1980, 28 lakes were classified as acidified with the MAGIC model, however, roach was present in 14 of these. In 2010, MAGIC predicted chemical recovery in 50% of the lakes, however roach only recolonized in five lakes after 1990, showing a lag between chemical and biological recovery. Our study is the first study of its kind to use long-term archival biological data in concert with hydrogeochemical modeling for regional assessments of anthropogenic acidification. Based on our results, we show how the conceptual model can be used to understand and prioritize management of physico-chemical and ecological effects of anthropogenic stressors on surface water quality.

Screening risk areas for sediment and phosphorus losses to improve placement of mitigation measures

“…The importance of transport over source factors also supports the suggestion by some authors that CSAs should be determined by working the P transfer continuum from the impact to the source (Reaney et al 2011). This is more in accordance with the requirement in current water legislation (e.g., the EU WFD and the US Clean Water Act) to prioritize measures when there is an effect on a valuable indicator species (Valinia et al 2014).…”

Long-term trends in water chemistry of acid-sensitive Swedish lakes show slow recovery from historic acidification

“…Using a conceptual model developed by Valinia et al ( 2014 ), it was possible to compare changes in pH between 1990 and 2010 to reference pH (Fig. 6 ).…”

“…Based on the results of this study, two key components can illustrate how decision making in Swedish water management can be improved: (i) We have illustrated the importance of monitoring programs to assess long-term changes in surface waters. Without long-term datasets, water management and classification of reference conditions become ambiguous without the support of monitoring data for surface waters; (ii) Based on the elusive baseline and the acceptance that undisturbed state might be an inadequate criterion for prioritizing water management (Valinia et al 2014 ), we can use acid-sensitive lakes as an example to prioritize restoration measures in recovering Swedish surface waters including reintroduction of extirpated species and possibly liming. The acid-sensitive lakes in this study (Fig.…”

“…To assess changes between reference conditions and contemporary conditions, a conceptual model described by Valinia et al ( 2014 ) was used. The conceptual model makes a graphical presentation of movement toward or away from reference conditions over time.…”

Potential for long‐term transfer of dissolved organic carbon from riparian zones to streams in boreal catchments

“…Boreal peatlands and permafrost regions store most of the world's terrestrial carbon (Post et al, 1982;Gorham, 1991;Tarnocai et al, 2009) and export large amounts of organic carbon to inland waters (Battin et al, 2009). In the aquatic environment, dissolved organic carbon (DOC) plays a key role in food web interactions and biodiversity (Williamson et al, 1999;Karlsson et al, 2012), water acidification status (Erlandsson et al, 2011;Valinia et al, 2014), and mobilization of toxic metals and organic pollutants (Shafer et al, 1997;Dawson et al, 2009). DOC also interferes in water treatment processes (Lavonen et al, 2013).…”