Conceptualizing and communicating management effec

Authors: Martyn N Futter Lars Högbom Salar Valinia Ryan A Sponseller Hjalmar Laudon

Publish Date: 2016/01/07

Volume: 45, Issue: 2, Pages: 188-202

PDF Link

Abstract

We present a framework for evaluating and communicating effects of human activity on water quality in managed forests The framework is based on the following processes atmospheric deposition weathering accumulation recirculation and flux Impairments to water quality are characterized in terms of their extent longevity and frequency Impacts are communicated using a “traffic lights” metaphor for characterizing severity of water quality impairments arising from forestry and other anthropogenic pressures The most serious impairments to water quality in managed boreal forests include i forestry activities causing excessive sediment mobilization and extirpation of aquatic species and ii other anthropogenic pressures caused by longrange transport of mercury and acidifying pollutants The framework and tool presented here can help evaluate summarize and communicate the most important issues in circumstances where land management and other anthropogenic pressures combine to impair water quality and may also assist in implementing the “polluter pays” principleForests cover approximately 2/3 of Sweden and forestry contributes 2  of GDP Skogsstyrelsen 2014 Because they cover a relatively large proportion of the Baltic Sea drainage basin runoff from Swedish forests has a major influence on water quality in the marine environment Brandt et al 2008 The vast majority of Swedish forests are managed for biomass production and there are demands for further intensification to meet the goals of an emerging bioeconomy Egnell et al 2011 This near universal anthropogenic shaping of the forest landscape has been ongoing for several centuries making it difficult to separate background or reference condition levels from the effects of presentday management activities Renberg et al 2009 Furthermore Swedish forests have been subject to a range of nonforestryrelated environmental stresses which have degraded water quality Much of the forest area in southern Sweden is still recovering from the legacy of acid deposition Akselsson et al 2013 Moldan et al 2013 which has led to ongoing surface water acidification Futter et al 2014 and slow biological recovery Valinia et al 2014 Most of the nitrogen N and mercury Hg deposited on Swedish forests is the result of emissions in other regions and longrange transport Almost all of the organic micro pollutants OMPs including legacy and emerging persistent organic pollutants are anthropogenic in origin Forestry activities can if carried out without proper consideration exacerbate negative effects on water quality by altering rates of biogeochemical cycles depleting element pools or mobilizing atmospherically deposited pollutants Kreutzweiser et al 2008 Lattimore et al 2009 Laudon et al 2011 Thiffault et al 2011 Palviainen et al 2015In 2000 member states in Europe adopted the Water Framework Directive WFD as an overall goal for water management EC 2000 The WFD moved towards ecological integrity as a focal point of management instead of traditional sectoral strategies This led to a comprehensive list of physical biological and chemical parameters to be used when classifying surface waters in Europe HattonEllis 2008 The overall goal of the WFD is to reach Good Ecological Status GES which is defined as a state with minor influence from anthropogenic alterations hence an undisturbed state EC 2000 Annex V The undisturbed state is determined by reference conditions which are assumed to have existed before major industrialization urbanization and intensification of agriculture EC 2003a The reference condition concept has been criticized for problems with interpretation and identification of the undisturbed state Moss 2008 Hering et al 2010 Valinia et al 2012 In particular it is important to recognize that reference conditions cannot and should not be equated with “natural conditions” sensu Siipi 2008 Indeed given the long history of human habitation and that almost all forests in Sweden are managed reference conditions represent something of an idealizationThe WFD also enshrines the “polluter pays principle” EC 2000 which embodies the concept that polluters are responsible for the pollution they have caused While this principle appears simple its implementation can be complicated especially in situations where pollution is caused by more than one polluter Lindhout and Van den Broek 2014 This is especially relevant in managed forests where water pollution may be the result of a combination of deposition of pollutants from longrange transport and their subsequent mobilization by forest management activitiesWhile water quality in managed Swedish forests is generally good when compared to agricultural and urban regions Sponseller et al 2014 as well as to other countries in Europe there are valid concerns about the potential consequences of forestry activities for achieving Good Ecological Status However one of the main obstacles when using the WFD to communicate the effects of forestry on Swedish surface waters is that its complexity overwhelms foresters decision makers scientists and other actors Futter et al 2011 Berglund 2014 Keskitalo 2015 and that the results of status classifications can be counterintuitive For example the “one out all out” principle under which the worst result from a series of metrics eg phytobenthos fish and insects is used for ecological status classification leads to nearpristine forest streams failing to achieve good ecological status Löfgren et al 2009 However this could be resolved with typespecific reference conditions since using individual classification of surface water bodies as the WFD requires where a naturally acidic system should be classified as naturally acidic without major anthropogenic influence Compared to previous ecological quality criteria EQC where threshold values were used naturally acidic systems would be wrongly classifiedEffects of forestry on boreal ecosystem status and surface water quality have been the subject of numerous reviews Kreutzweiser et al 2008 Bishop et al 2009 Lattimore et al 2009 Laudon et al 2011 Thiffault et al 2011 Palviainen et al 2015 We have no intention of duplicating this material but instead focus on frameworks for the conceptualization and communication of water quality issues related to forests and forestryWe focus on eight surface water quality parameters which can be adversely affected by forestry or other anthropogenic activities These include runoff volume suspended sediments N phosphorus P dissolved organic carbon DOC base cations BC Calcium Potassium Sodium and Magnesium Hg and OMPs These parameters represent key physical and chemical attributes of streams lakes and rivers biological responses to anthropogenic disturbance are considered insofar as they are caused by the above eight issues Hydromorphological alterations while important are not considered furtherHere we propose a simple conceptual framework for evaluating biogeochemical cycles in the boreal forest and a tool for communicating the manner in which forestry operations may alter these cycles We use the framework to explore controls on water quality in intact forests and to rank the impacts of forestryrelated disturbances on water quality at local landscape and national scales Specifically we pose three questions about water quality connected to forests and forest management First do forests or forestry affect the cycling of the chemical species in question and if so how strong is the effect second what are the effects of presentday forestry on the water quality issue third and most important how certain is the science used to answer the first two questions

Keywords: