initiatives—to restore the health of local nature, to implement the Chicago Wilderness Green Infrastructure Vision, to mitigate and adapt to climate change, and to leave no child inside—reflect our commitment to using science and emerging knowledge, a collaborative approach to conservation, and a caring for both people and nature, to benefit all the region’s residents.
The actions necessary to achieve this mission were laid out in the Chicago Wilderness Biodiversity Recovery Plan in 1999 and still drive conservation strategies of the alliance today. The science driven process used to develop this plan identified habitat destruction and fragmentation, invasive species, and pollution as the major systemic threats that created vulnerability to the native terrestrial and aquatic biodiversity of the Chicago Wilderness region. There is now overwhelming scientific evidence to support that climate change is amplifying the effects of these threats, and that there will likely be synergistic effects between existing stresses and threats and climate change impacts to those threats (e.g., Opdam and Wascher, 2004; IPCC, 2007). For example, as the climate changes many species will need to shift their geographic ranges in order to track appropriate environmental conditions needed to survive. The ability of species to successfully migrate, however, may be hindered by a fragmented landscape that can inhibit or even block the migration of species. As Chicago Wilderness summers become hotter and drier due to climate change, the hydrology of wetlands will likely be altered and possibly cause some wetland areas to dry up and others to become even more isolated- further exacerbating the threat that fragmentation poses to wetland communities and species in this region.
Recognizing the potential of climate change to jeopardize the conservation investment that has taken place in our area, in 2007 the Chicago Wilderness Executive Council established Climate Change as one of four thematic initiatives, along with the Green Infrastructure Vision, Leave No Child Inside, and Restoring the Health of Local Nature. To define and carry out the work of this initiative, Chicago Wilderness established the Climate Change Task Force (Task Force) to “study and make recommendations on adaptation strategies and models for mitigation in order to address the local impact of climate change.” In 2008, the Task Force produced Climate Change and Regional Biodiversity: A Preliminary Assessment and Recommendations for Chicago Wilderness Member Organizations (see Box 1 below) that reviewed the current science of climate change and summarized the dramatic changes projected for the Chicago Wilderness climate system and expected impacts to biodiversity.
Box 1: Past Climate Changes and Projected Future Trends in the Chicago Wilderness Climate System (since the mid-20th century).
|Recent Changes in Climate||Changes Expected by Middle to End of this Century*|
* The range of values/changes represents different scenarios for greenhouse gas emissions during the 21st century.
Data Sources: City of Chicago (2008); Union of Concerned Scientists (2009); Technical Input to the 2013 National Climate Assessment, July 2012.
Chicago Climate Action Plan (CCAP) that inherently focuses on mitigating emissions from buildings and transportation, as they account for 90% of the city’s total emissions. The Chicago Climate Action Plan strategies aim to reduce climate impacts on people, the built environment and city services, and also include adaptation strategies for natural areas and green spaces. Subsequently in 2010, Chicago Wilderness developed the Climate Action Plan for Nature (CAPN) that complements the Chicago Climate Action Plan by focusing exclusively on conservation of native species, natural areas, and ecosystem services (see Figure 1.2, right). The Climate Action Plan for Nature expands the geographic scope to include the entire 6 million acre Chicago Wilderness region, and lays out specific actions for engagement, mitigation and adaptation aimed at promoting and sustaining biodiversity in a changing climate.
Sustaining the functions of ecosystems is also very important to the long-term health and well being of people in the region. By having complementary documents and processes for people and nature, we will be well positioned to identify opportunities where investments in restoring or enhancing natural systems can provide effective alternatives to investments in hard infrastructure (e.g., in areas like flood control/storm water handling, water quality), and provide additional benefits to these ecosystem services.
While there are many uncertainties about climate change impacts and how Chicago Wilderness conservation practitioners should react, the cost of doing nothing at all is likely to be far greater in the long-term than waiting until those uncertainties diminish (Karetnikov et al., 2008). Ignoring climate change may result in the failure to reach biodiversity recovery management objectives, and in fact may lead us to engage in actions that do more harm than good. Further, as some of the adaptive responses that are focused on benefiting people may be detrimental to natural systems, anticipating human responses and working pro-actively on helping communities view functioning natural systems as tools for adaptation should be a high priority for Chicago Wilderness members. The adverse effects of climate change on wildlife and their habitats may be minimized, or even prevented in some cases, through adaptation actions that we initiate now (Inkley et al., 2004).
The Chicago Wilderness Biodiversity Recovery Plan (BRP) Climate Change Review is closely connected to the Climate Action Plan for Nature mission and goals. The Biodiversity Recovery Plan was developed as a living document that would continue to evolve as new information and new ideas arose. Over the past decade, it has become clear that global climate change is one of the top threats facing our environment. In addition to efforts to restore biodiversity, we must also work to minimize our losses and maximize our chances for successful biodiversity adaptation. To move toward this goal, it is valuable to review the original conservation targets and threats outlined in the Biodiversity Recovery Plan in light of what we now know about climate change.
“It is not the strongest of the species that survive, nor the most intelligent, but the ones most responsive to change!” - Charles Darwin
Given the uncertainties in projecting the extent and rate of climate change, the Global Climate Change and Wildlife in North America technical report (Inkley et al., 2004) recommends managing for a range of possible future conditions. This means identifying actions that provide relatively high returns on the conservation investment for a relatively wide range of future climate conditions. These measures are often referred to as “no-regret” strategies, or options that would be justified under all plausible future scenarios, including the absence of human-induced climate change (Eales et al., 2006). The strategies developed for the Chicago Wilderness Biodiversity Recovery Plan Climate Change Review are designed to reflect this conservative principle. Developing these types of strategies may involve shifting toward a risk assessment/scenario approach to management planning. For example, thinking through multiple possible future scenarios that not only include assessments of what the most likely outcome will be, but also what conditions could mean if a chosen management plan fails. Given that some actions may fail, one of the best strategies is to “hedge your bets” and add in safeguards. In short, we want to protect more than we think we will need given that uncertainties exist. Accordingly, adaptive management will play a key role in helping us learn from what seems to work and what does not. Now, more than ever, it is critical that experimental designs are employed when possible to implement changes in management, and that monitoring regimes are established to enable us to learn and change paths if needed as the climate continues to change.
The tenets of the Biodiversity Recovery Plan Climate Change Review (the Review) are imbedded within the Climate Action Plan for Nature adaptation section. This document, however, is intended to be a more detailed and stand-alone reference that supports the development of specific adaptation strategies for the natural communities of Chicago Wilderness. The general aim of the Review is to provide a tool that assists land managers, policy makers and individuals in creating and implementing strategies for biodiversity recovery and adaptation in Chicago Wilderness. In addition, this information is intended to encourage discourse on the ways in which climate change may influence how we think and act. For example, communities as we know them are likely to change, as all of the component species may respond to climatic changes in different ways and at different rates (Root and Schneider 2006). As such, we may need to shift from thinking about “communities” from a static perspective, to focusing more on specific conservation targets and the functionality of ecosystems. The goals of this document are to 1) discuss the impacts of climate change on specific Chicago Wilderness conservation targets and threats 2) evaluate the conservation strategies currently being used in Chicago Wilderness through a climate change lens and 3) outline actions and strategies that can help promote biodiversity adaptation for specific conservation targets.
The process used to carry out the Review began with the Chicago Biodiversity and Stormwater expert workshop, held in July 2009 in Chicago, IL. This workshop was led by US Environmental Protection Agency- Region 5, Chicago Department of Environment, The Nature Conservancy (TNC) and Chicago Wilderness (CW), and built from earlier The Nature Conservancy work summarizing impacts and discussing priority areas for adaptation action in the Great Lakes region. Based on their background and expertise, participants worked in terrestrial, aquatic, or storm water discussion groups. The groups were presented with a list of global climate change impacts gathered from the scientific literature by Dr. Kim Hall, Great Lakes Climate Change Ecologist for The Nature Conservancy, and they ranked those threats for the Great Lakes region. The Chicago Wilderness Climate Change Task Force further refined the “greatest impacts” list by assessing which impacts were most likely to threaten Chicago Wilderness in particular, based on projected changes in regional climate (assessment based on: Fourth Assessment Report by the International Panel on Climate Change, 2007; Confronting Climate in the US Midwest by the Union of Concerned Scientists, 2009; and information from the scientific literature). Finally, local scientists and land managers were interviewed to gather their observations and insights into how climate change is affecting specific ecosystems, communities and species in the Chicago Wilderness region, and what tools might be needed to successfully implement biodiversity adaptation strategies.
Climate Change Issues for Illinois and the Chicago Wilderness Region
While there are limits to the accuracy of future climate projections—based mainly on the uncertainly of what future global emissions will be and current limitations in our knowledge about how the earth’s climate system will respond to it—long-term projections from global climate models (GCM’s) that are based on the average of multiple models and many climate simulations represent robust information for aspects of future climate (National Research Council, 2010). For instance, there is high confidence that the global average temperature will continue to rise (National Research Council, 2010). Projections for future precipitation, however, are more complicated. There is less certainty regarding projections for the directionality and range of annual precipitation, but agreement that the pattern is likely to shift to fewer but more extreme storm events (National Research Council, 2010).
Downscaled models are also beginning to provide useful information about future climate changes on local to regional scales as well. The consensus projections from various models for North America, including the Chicago Wilderness region, indicate there will be an increase in the average annual temperature (much of the warming concentrated during the cool season and at night), more hot extremes and fewer cold extremes, reduced daytime temperature ranges, increases in extreme precipitation events, and a seasonal shift to wetter winters and springs and more summer droughts (Field et al., 2007; Hayhoe and Wuebbles, 2008; UCS, 2009; USGCRP, 2009; Vavrus and Van Dorn, 2010; National Climate Assessment in press). Downscaled modeling done for Chicago based on higher (SRES A1F1) and lower (SRES B1) greenhouse gas emissions scenarios suggests the coldest night of the year is projected to warm by 4–8 °C, while the simulated occurrence of very cold conditions (daily minimum temperature < −18 °C) declines by ∼ 50% (5 days, B1) to nearly 90% (8 days, A1F1) relative to the late 20th century (Vavrus and Van Dorn 2010).
click here. The tool used to visualize this data set is Climate Wizard, and was developed by The Nature Conservancy to allow easy access to climate data, future projections and impacts for a given region. The data can be viewed to reflect annual, monthly, or seasonal patterns. For example, between 1957–2006 the annual average temperature across the entire Chicago Wilderness region did not increase significantly (however parts of SE Wisconsin and NW Indiana did), but falls have become cooler while winters, springs and summers have become warmer. Looking at monthly changes during this 50-year period, it is evident that October has become significantly cooler and March has become significantly warmer. The Union of Concerned Scientists (2009) acknowledges that the climate of Illinois has already changed measurably over the last half century in the patterns of temperature and precipitation, and these changes are expected to continue (see Box 1). For example, if current emission trends continue, by the end of the century Illinois could be facing multiple heat waves per summer with more than a month of days over 100° F, warmer winters (due to increases in the nighttime minimum temperatures) that allow many pests to expand their range, winters and springs that are 25 percent wetter, more extreme precipitation events, and drier summers (Hayhoe et al., 2010).
While much of the current climate change dialogue centers on future impacts, many of these trends have already begun (see Box 1). For example, July 2011 broke records across the nation, including the Chicago region, with a heat wave that was characterized by unusually warm minimum temperatures during nights and early mornings. This pattern is typical of U.S. heat waves in the last decade, and consistent with increasing warm summer nighttime extremes observed across much of the country since the late 20th century (Illinois State Water Survey, 2011). In the summer of 2011, Chicago went from having the third driest to the second wettest July on record in one single event when 6.86 inches fell in 3 hours on July 23rd. In total, July 2011 accumulated 11.15 inches, surpassing the previous wettest record set in 1889 with 9.56 inches (chicagoweathercenter.com; climatestations.com).
While it is not possible to claim one particular weather event is due specifically to climate change, the types of extreme events the Chicago region has experienced (e.g., the heat wave of 1995, summer flood events of 2008, 2010, 2011) are very likely to increase in frequency with climate change in the coming decades. This expectation is based on the fact that a warmer world holds more moisture. As the climate warms, evaporation of moisture from the oceans increases, resulting in more water vapor in the air. According to the 2007 Intergovernmental Panel on Climate Change (IPCC) report, water vapor in the global atmosphere has increased by about 5% over the 20th century, and 4% since 1970. This additional moisture then comes down in larger and more extreme storm events. Heavier storms and flooding and more extreme heat events can have serious direct consequences for human health, such as deteriorating water quality, and the viability of crops and livestock. Similarly, the major threats natural communities now face, such as habitat fragmentation, invasive species and pollution, will no doubt also be exacerbated by climate change impacts (USGCRP, 2009).
Another example rapid changes are underway is illustrated by the recent shift seen in plant hardiness zones throughout the United States, a metric based on average minimum winter temperatures that determines what plant species can be cultivated in a region. The USDA released a revised plant hardiness zone map in January 2012, and when compared to the 1990 version the zone boundaries in this edition of the map have shifted in many areas. The new map is generally one 5-degree Fahrenheit half-zone warmer than the previous map throughout much of the United States. For example, Chicago shifted from a 5b to 6a zone between 1986 and 2005. This is mostly a result of using temperature data from a longer and more recent time period; the revised map uses data measured at weather stations during the 30-year period 1976–2005. In contrast, the 1990 map was based on temperature data from only a 13-year period of 1974–1986. Irrespective of future emissions scenario, plant hardiness zones are projected to continue moving northward. The extent to which plant hardiness zones shift by the middle or end of the century, however, will depend on the level of greenhouse gases that are emitted. For example, by mid-century, plant hardiness in Chicago is projected to remain at zone 6a under lower emissions and to shift further to zone 6b under higher emissions. By the end of the century, the projected hardiness zones could shift to 6b under lower and to 7a under higher emission scenarios (Hellmann et al., 2010).
The projected shifts for mid- and late-century under the lower emission scenario would make conditions in the region equivalent to present hardiness zones in southern Illinois. Under the higher emission scenario, plant hardiness zones are projected to be similar to those of western Kentucky by mid-century and to northern Alabama by the end of the century. Projected shifts in plant hardiness zones, as well as decreases in growing season moisture due to warmer, drier summers, will have implications for the nearly 100 tree species and the larger numbers of shrubby and herbaceous species, not to mention the wildlife community that depend on them, that occur in the Chicago Wilderness region (McLachlan et al., 2007; Hellmann et al., 2010).
The inability of natural communities to adapt to this rapid climate change will result in their diminishing capacity to provide many ecosystem services, such as clean water, habitat for fisheries, pollination, recreational opportunities, climate stabilization, and carbon sequestration. These losses are expected to grow as climate change deepens, along with the inherent cultural, aesthetic, and quality of life values imbedded in the very existence of natural communities.
Climate Change and Biodiversity
It has long been recognized that biodiversity at all scales (genes, species, ecosystems, etc.) is key to the health of the natural world (e.g., Rapport et al., 1998; UNDP, 2000) and, in light of our planet’s rapid climate change, having healthy, resilient natural communities may now be more important to us than ever (Thomas et al., 2004; Hampe and Petit, 2005). Greater genetic biodiversity within populations will enable them to be more resilient to changing temperatures and precipitation patterns; just as recovering and conserving species biodiversity within communities will aid them in sustaining their functionality (Thomas et al., 2004). It is important that biodiversity recovery plans integrate the knowledge of how our region’s climate is changing, and how our ecosystems are expected to respond to it, into their strategies and actions. In a human-dominated landscape such as Chicago Wilderness, it is especially relevant to try and anticipate human responses that may lead to increased stresses on biodiversity (e.g., natural areas adjacent to localities that are likely to be further developed could be negatively affected by stormwater runoff and flooding associated with increases in impervious surfaces).
A vital aspect to consider about climate change impacts is not just how changes in mean temperatures and precipitation patterns will affect ecosystems and wildlife, but how the resulting variability and extremes will impact them (Table 1,Table 4,Table 5 and Plants page; Inkley et al., 2004). The complexity of these changes, and the interaction between them, means that some impacts are difficult to predict. Rapid changes in conditions will likely result in native species facing increasing threats from pests, diseases, and competition from non-native species (see Plants page, section 2.3) moving in from warmer regions (USGCRP: Midwest Regional Climate Impacts, 2008). While it is expected that the geographic ranges of flora and fauna will shift upwards in elevation and northward (Parmesan, 2006), the pattern and extent of movement will vary tremendously among species based on factors such as dispersal ability, life history traits, genetic diversity and behavioral plasticity (Thomas et al., 2004). Ultimately, however, the ability of species to physically shift their range is dependent on the availability of migratory pathways, which are threatened by barriers such as roads, cities, and habitat fragmentation (Easterling et al., 2004).
Since temperature has played a strong role in shaping species life histories, and has been a key element in genetic, physical and behavioral adaptation over long (evolutionary) time periods (Millien et al., 2006), there is great potential for wildlife to be significantly affected by rapid temperature changes. In fact, responses to increasing temperatures have already been observed in wild animals and plants, and can be grouped into five basic, but not mutually exclusive, types (from Hall and Root, 2012):
- spatial shifts in ranges and boundaries (e.g., moving north in the Northern Hemisphere);
- spatial shifts in the density of individual animals and plants within various subsections of a species’ range;
- changes in phenology (the timing of events), such as when leaves emerge in spring or when birds lay their eggs;
- mismatches in the phenology of interacting species; and
- changes in genetics.
In general, for animals, the potential effects of temperature changes will likely be most apparent for ectothermic (cold-blooded) animals such as insects, reptiles and fish because their body temperature closely tracks environmental temperature. However homeothermic, or warm-blooded, animals like birds and mammals are also at risk of heat-related stress as temperatures continue to increase, especially those that inhabit areas where they are already close to their thermal tolerance limits (Hall and Root, 2012).
Observations of changes in phenology in wild animals and plants show a robust and geographically widespread trend. A recent paper by Thackeray et al. (2010) reports on the analyzed observations of more than 700 species of fish, birds, mammals, insects, amphibians, plankton and a wide variety of plants across the U.K, taken between 1976 and 2005. The authors found a consistent trend revealing more than 80% of biological events (e.g., including flowering of plants, ovulation in mammals and migration of birds) occur earlier in the annual cycle than they did in the 1970s. Changes in snowfall and temperature can delay the onset of hibernation, such as yellow-bellied marmots (Marmota flaviventris) in Colorado that have been observed emerging 38 days earlier compared to the 1970s (Inouye et al., 1999).
While some phenological events are occurring earlier, there is also evidence that others could be happening later. Although there have been no comprehensive studies performed in the U.S. yet, some data points toward later leaf drop. For example, researchers at the NASA Goddard Space Flight Center and at Seoul National University in South Korea used satellites to show the end of the growing season was delayed by 6.5 days from 1982 to 2008 in the Northern Hemisphere. Further support for this hypothesis comes from experimental research conducted on deciduous forest species from contrasting climates (Liquidambar styraciflua, Quercus rubra, Populus grandidentata, and Betula alleghaniensis). Researchers exposed tree species to air temperatures 2 and 4°C above ambient controls and found chlorophyll was retained an average of 4 and 7 days longer in +2 ° and +4 °C treatments, respectively, and abscission was delayed by 8 and 13 days (Gunderson et al. 2011). This indicates temperature alone can affect later leaf drop, and that even if this pattern is not widespread now, it could be in the future.
(D. Stotz, pers. comm.). The onset and duration of animal hibernation is tightly linked with temperature too. A long-term study on the relationship between ambient (air/soil) temperature and the torpor patterns of free-ranging Eastern chipmunks (Tamias striatus) in southeastern New York suggests exceptionally high winter temperatures correlate positively with reduced hibernation, resulting in a lower winter survival rate for these animals (Frank, 2012). The above patterns are consistent across different habitat types suggesting a large-scale phenomenon, and are certainly consistent with what would be expected in a warming world.
(D. Stotz, pers. comm.). It is possible that if this type of de-synchronization continued, it could have extreme negative effects on populations of warblers. Further, if the predation by migratory birds are crucial to controlling the insect pest abundance, this timing mismatch could result in increased herbivory on the trees as they leaf out, reducing their fitness.
All of the broad wildlife taxonomic groups are likely to be impacted by climate change in some way in the coming decades. However the impacts will vary in kind (positive or negative) and in scale for different species. A species’ vulnerability to climate change is a function of the 1) exposure to a changed climate factor, 2) sensitivity to that factor, and 3) adaptive capacity to respond to change. While it is not possible to predict exactly how species will respond to climate change, we are able to anticipate some likely responses based on our current knowledge, observations, and ecological theory. Table 1 lists climate change impacts for each major taxonomic group in Illinois and provides examples of the ways in which certain species are being, or likely to be, impacted by the expected changes in climate. Predicting the precise effects of climate change on plants and animals is extremely challenging and hindered in part by the lack of information on interactions among biotic and abiotic components of ecosystems, as well as the uncertainties related to non-climate stressors on ecosystems (Inkley et al., 2004). This climate change review will highlight some of the critical research and monitoring initiatives needed to address these knowledge gaps in the Chicago Wilderness region.
It is also essential that we go beyond species-level management for natural communities and focus too on how climate change may impact biodiversity at the ecosystem level. An important challenge for us will be to scale up the relationship between ecosystem processes and biodiversity from small patches, where most empirical and theoretical studies apply, to the landscape level where most management issues are dealt with (Inchausti and Loreau, 2002). With expected migration patterns likely to reflect a decrease in species for which the Chicago Wilderess region is at the southern end of their range and an expansion for those at the northern edge (Karl et al., 2009), individual species will shift in and out of our ecosystems. It is not individual species that are necessarily of greatest concern, but the continued overall functionality of natural communities (e.g., water cycling, nutrient cycling, energy flow, community dynamics). A broader expansion beyond plant species, a primary focus of the Biodiversity Recovery Plan, to assess the effectiveness of restoration methods has great merit. For example, monitoring ecosystem processes like soil biogeochemical cycling, or using terrestrial arthropod indicators in conjunction with other plant and animal indicators can be very useful in providing early warnings of ecological changes, and can be used to assess the effects of further fragmentation on natural areas that no longer support vertebrate indicator species (Beier and Brost, 2010; Kremen et al., 1993).
Experts agree that, at the site scale, most actions that are needed to help protect Chicago Wilderness biodiversity under future conditions are the same types of actions that we currently engage in to reduce the risk of a wide range of other threats (e.g., Glick et al. 2009). For example, actions such as removing invasive species and restoring fire-dependent systems “count” towards climate change adaptation. These actions strengthen native ecosystems making them better able to respond to the stresses they will face with climate change. The detailed implementation of these strategies, however, may change when viewed from the perspective of climate change adaptation. In the following sections we will review how climate change is likely to impact terrestrial and aquatic communities, as well as the threats to those communities, and outline conservative adaptation strategies aimed at helping to restore biodiversity and sustain functionality. We will also discuss how climate change may influence particular ecological concepts and review the role that climate change adaptation can play in the Green Infrastructure Vision of Chicago Wilderness. An important resource is on the Plants page, which presents both theoretical knowledge and empirical evidence on how current climate change impacts plants and natural communities around the world. The intention of this resource is to provide the best available science on this topic and foster discussion on how and in what ways this information is applicable and relevant to the natural communities in Chicago Wilderness.