Scientific advances and adaptation strategies for Wisconsin lakes facing climate change

Figures & data

Figure 1. (a) Lake levels: increased precipitation may cause flooding and property damage on some lakes (photo credit: Katie Hein); (b) water quality: increased runoff and warmer air temperatures will increase the frequency of harmful algal blooms on Wisconsin’s inland lakes (photo credit: Sarah Collins); (c) aquatic invasive species: climate change will make management of AIS, such as spiny water flea, more difficult in Wisconsin lakes (photo credit: Jake Walsh); (d) fisheries: changing temperatures are predicted to result in shifts in distribution of important freshwater fish, such as walleye (photo credit: Gretchen Hansen).

Table 1. Adaptation actions generated for each of the four workshop themes. Adaptation actions fall into four broad categories of communication and outreach actions, policy and regulation actions, traditional conservation actions, and engineering actions.

Lake levels
Communication	Monitor and define the range of lake levels expected Identify seepage lakes in the state with large lake level fluctuations Shift cultural norms regarding idyllic lake shorelines to include natural vegetation and minimize human structures
Policy	Set zoning regulations that protect the riparian zone from development Set insurance policies based on future climate projections to minimize building below the high-water mark Promote voluntary practices that protect undeveloped shorelines and wetlands Limit groundwater extraction to maintain minimum lake levels during drought Incentivize agricultural and urban development practices that minimize water use and encourage water infiltration
Conservation	Protect and restore wetlands and lake habitat in riparian and littoral zones Add woody and other habitat to deep water so it is available when lake levels are low Protect woody and other habitat stranded above water so it is available when lake levels rise Tailor agricultural practices to local climate and geology to conserve water and minimize drawdown in lakes
Engineering	Build adaptable/temporary structures, such as rolling or floating piers Enhance water infiltration in the watershed and in the riparian to minimize flooding after extreme precipitation events Manage lake levels with dams to anticipate future highs and lows Lakes maintained artificially high for summer recreation are more at risk of flooding Lakes drawn down especially low to protect structures from ice are more at risk of staying low in drought years Pump water out of seepage lakes when water is too high Design infrastructure to accommodate extreme events
Water quality
Communication	Address disconnect for stakeholders who value high water quality but dislike management and regulations Develop community connectedness with stakeholders Draw input from lake associations to drive large preventative measures at the local level Increase communication with stakeholders about drivers of water quality and how climate change may affect drivers Communicate economic advantages of improved water quality to businesses and other stakeholders
Policy	Incentivize companies and farmers to reduce nutrients runoff in the watershed Continue implementation of total maximum daily load (TMDL) programs Reevaluation of water quality standards and permitting standards to reduce phosphorus, chloride, and fecal contaminants Remove combined storm overflows in urban areas Improve stormwater regulations and enforce management practices that reduce runoff and nutrients in urban areas
Conservation	Best management practices for nutrient reductions Limit fertilizer application Grazing and pasture management Riparian and buffer zones Wetland protection and restoration Reduce application of road salt during winter months Saturated buffers to reduce phosphorus and nitrate loads entering streams from tile-drained agricultural fields
Engineering	Maintain beach usage through enclosed swimming and treatment systems Artificial aeration to prevent anoxic conditions to sustain well-oxygenated waters for cold-water fisheries Increase green infrastructure Dredging of legacy phosphorus in impacted stream reaches Constructed water treatment wetlands and detention ponds
Aquatic invasive species
Communication	Continue outreach efforts to maintain 100% compliance with AIS prevention efforts Expand youth education and community-based social marketing to achieve higher compliance rates Develop simple and consistent messaging Better articulation of socioeconomic impacts of invasion Advertise the successes of outreach efforts in preventing invasions
Policy	Develop proactive long-term monitoring and studies Develop regulations that close existing and potential future transport vectors Proactively incorporate AIS management into regulation regarding water quantity management Incentivize invasive species harvest at the edge of invasion Adjust ballast water regulations to decrease risk of invasion Alter standards for boat manufacturers that require design for AIS prevention and decontamination
Conservation	Promote strategies to increase general health (i.e., resilience) of lakes and reduce AIS impacts Develop local-scale prediction and prevention strategies Use long-term monitoring to identify changes in AIS distributions, pathways, and impacts as climate changes Improved detection methods to identify and manage AIS before they become established Develop biological control programs for common AIS species Provide funding and resources for communities and lake associations to control AIS at the local level
Engineering	Recreational boat and shipping vessel decontamination Ballast water treatment Changing watercraft design to make AIS prevention easier Fish passage barriers Electric barriers Physical barriers (dams) Acoustic deterrents Carbon dioxide deterrent Chlorinated locks to prevent AIS from passage
Fisheries
Communication	Coupled natural–human systems studies enhancing understanding of human role on fisheries systems under climate change Outreach on the safe operating space concept Encourage and/or enhance manager and stakeholder partnerships Increased transparency in scientific and management basis for regulations Set realistic expectations and goals for fish communities based on lake conditions
Policy	Harvest regulations (length and bag limits, closed seasons) to reduce exploitation rates Stock appropriate genetic strains to maintain local adaptation Cost–benefit analysis of stocking policies for maintaining the fishery Alter inland fishery management to what the lake can currently support Increase protection of forested watersheds
Conservation	Continue long-term monitoring programs of sentinel lakes Purchase land in watersheds of resilient lakes with high-value fisheries Add structural habitat that is resilient to water-level fluctuations Reduce nutrient loading in watersheds to reduce anoxic conditions and maintain available cold- and cool-water fish habitat Stock genetically resilient strains
Engineering	Artificial aeration of lakes with low dissolved oxygen to provide refugia for cold-water fish species

Figure 2. Climate change affects each step or filter of the invasion process. Here, we present an example of three potential invasion filters (colonization, establishment, and impacts) where climate change affects the underlying ecology of each filter. As each filter is altered, we expect to observe change in the dynamics and impacts of AIS. As a result, AIS will be more challenging to manage under climate change, particularly since each of these filters are directly linked and often will be changing simultaneously.

Figure 3. Conceptual diagram of a multi-faceted climate adaptation strategy for Wisconsin’s inland lakes. Resistance, resilience, and response are effective adaptation approaches when tailored to the local communities’ values and lake ecosystem. Each of these adaptation approaches can be achieve through adaptation actions that address communication and outreach, policy and regulation, traditional conservation actions, and innovation and engineering.