Ecological classification of large lakes in Finland: comparison of classification approaches using multiple quality elements

Abstract

Ecological classifications according to the Water Framework Directive (WFD) are presented for a set of 32 large (surface area [75 km 2 ) Finnish lakes. We compared three different approaches: classification according to the strictest biological quality element (One-out, All-out approach, OoAo); numerical integration of biological quality elements (BQE) to determine median scores; and the national classification based on weight-of-evidence (WoE) framework. We also examined the sensitivity of eutrophication metrics to phosphorus concentrations.OoAo classification, the national WoE approach gave similar, downgraded or upgraded status classes. Downgrading was due to the higher weight given to water quality and eutrophication pressures. Upgrading was due to the lower weight given to a single macroinvertebrate metric with poorly represented data. In our opinion, the classification based on the WoE approach produces more realistic status estimates than the OoAo classification. Nevertheless, in practical lake management the evidence from the strictest classification metrics still needs to be thoroughly considered.

Evaluating the impact of nutrient abatement measures on the ecological status of coastal waters: a Bayesian network for decision analysis

“…Different methods that integrate the knowledge about variables considered in the WFD ESC have been studied in freshwater ecosystems (Søndergaard et al, 2005;Alahuhta et al, 2009;Rask et al, 2011), but studies conducted in coastal environments are scarce. It is important to note that different approaches not only produce different absolute values but also alter the order in which the Finnish WFD areas changes relative to each other, when the effectiveness of nutrient abatement scenarios is considered (Figure 4).…”

An extended Benthic Quality Index for assessment of lake profundal macroinvertebrates: addition of indicator taxa by multivariate ordination and weighted averaging

“…The BQI is well suited for such assessment because it can be interpreted as measuring the community characteristics, 'ratio of disturbancesensitive taxa to insensitive taxa' and 'taxonomic composition,' included in the normative definitions of ecological status by the WFD (Jyväsjärvi et al 2010). The strong response of BQI to increasing and decreasing human disturbance has been well documented in contemporary (Rask et al 2011, Jyväsjärvi et al 2012) and palaeolimnological (Ilyashuk et al 2003, Meriläinen et al 2003, Hynynen et al 2004, Verbruggen et al 2011) studies. Another advantage of BQI for modern reference-condition-based assessments (Bailey et al 2004, Stoddard et al 2006) is that its sitespecific reference value can be predicted reliably from environmental variables (Jyväsjärvi et al 2010).…”

“…BQI also has been used provisionally as a metric in Swedish ( Johnson and Goedkoop 2007) and Finnish (Rask et al 2011, Jyväsjärvi et al 2012) bioassessments of lakes mandated by the Water Framework Directive of the European Union (European Commission 2000). The BQI is well suited for such assessment because it can be interpreted as measuring the community characteristics, 'ratio of disturbancesensitive taxa to insensitive taxa' and 'taxonomic composition,' included in the normative definitions of ecological status by the WFD (Jyväsjärvi et al 2010).…”

Approaches for integrated assessment of ecological and eutrophication status of surface waters in Nordic Countries

“…In contrast to the coastal assessments, the ecological status of lakes and rivers was determined in a comprehensive way emphasizing the importance of evaluating spatial and temporal representativeness of the monitoring data. First, a mean across normalized ecological quality ratios (EQRs) of BQEs was calculated for each water body Rask et al 2011;Aroviita et al 2012). Then the support from indicators of the physico-chemical and hydromorphological quality elements was included by regional experts into the status assessments by applying precautionary principle.…”