Ecosystems Ecosystem Services and Biodiversity

errestrial and marine ecosystems supply the foundation for human well-being and livelihood through the food, water, timber, and other goods and services they provide. Advances over past decades have also revealed the importance of less visible but equally important services that ecosystems provide for society, such as water filtration, carbon storage, maintenance of biodiversity, protection from storm disturbance, and stabilization of local climates. Climate change has already led to a number of changes in both terrestrial and marine ecosystems, and future climate change will strongly influence biodiversity, ecosystem processes, and ecosystem services, adding to other stresses on ecosystems from human activities.

Some questions decision makers are asking, or will be asking, about ecosystems management in the context of climate change include the following:

• How is climate change—including changes in temperature, precipitation, and the chemistry of the atmosphere and oceans—altering the distribution of species?

• Will these changes have major economic and social consequences, such as the loss of pollination services or valuable fisheries?

• How does climate change relate to other ecosystem stresses, such as pollution and habitat loss?

• Can ecosystems be managed to improve their ability to adapt to anticipated changes?

• Is it possible to manage forests and other ecosystems in ways that can help limit the magnitude of future climate change?

Decades of focused research on terrestrial and marine ecosystems and their biodiversity have improved our understanding of their importance for society and their interactions with other components of the Earth system. The findings have been the subject of many authoritative syntheses and assessments, including those by the Pew Oceans Commission (2003), the Pew Center on Global Climate Change (Parmesan and Galbraith, 2004), the U.S. Commission on Ocean Policy (2004), the Millennium Ecosystem Assessment (MEA, 2005), the Intergovernmental Panel on Climate Change (IPCC; Fischlin et al., 2007), the Heinz Center (2008a), the National Research Council (NRC, r

BOX 9.1 Glacier National Park

Glacier National Park is rapidly losing its namesake as summer temperatures rise and its glaciers disappear (see figure on facing page). The park, which straddles both the Continental Divide and the U.S.-Canada border in Montana, has lost about two-thirds of its glaciers since 1850 (Hall and Fagre, 2003). Plant and animal species are struggling to keep pace as suitable habitats retreat uphill as the climate warms. For example, pine trees are invading open grassland as the tree line migrates to higher elevation, in turn reducing fodder available for grazing mountain goats, bighorn sheep, and other ungulates.

Glacier National Park exemplifies some of the key questions that land and natural resource managers face with climate change (Pederson et al., 2006):

• As glaciers recede, will loss of scenic value reduce the millions of dollars that tourists spend there each year?

• How will populations of the grizzly bear and other species fare under climate change?

• Will dwindling glacial melt reduce populations of trout, a staple of the grizzly's diet and the fishing-tourism industry?

• Will droughts cause grizzlies and other large mammals to alter their seasonal movements in search of food, potentially exacerbating conflicts with human populations in and around the park?

• Will landslides increase,threatening animal and plant habitats and human-built infrastructure in the park?

• How will changes in water flowing out of the park into three major river systems—the Missouri/Mississippi, the Columbia, and the Saskatchewan/Nelson—alter availability downstream for irrigation and hydropower?

• Will fire become more frequent, and should more resources be allocated to fire-fighting or preemptive forest management?

All of these questions highlight the need for improved understanding of how plant and animal species will respond to climate change and other stresses. Projections of climate change on finer spatial scales would provide input for land managers to begin to assess the implications in their local context. Studies and models of the complex interactions among climate, biodiversity, ecosystem processes, and

2008b), and the U.S. Global Change Research Program (CCSP, 2009b), among others. This chapter outlines some of the key impacts of climate change on terrestrial and marine ecosystems (see Box 9.1), including the effects of ocean acidification, and also briefly summarizes current scientific knowledge about the potential role of ecosystems in limiting the magnitude of climate change and possible strategies for helping ecosystems adapt to climate change and other environmental stresses. The last section of the chapter outlines key research needs in all of these areas.

human decisions would provide a scientific basis for management decisions such as land use zoning, fire and forest management, animal population control, infrastructure maintenance, and habitat restoration appropriate for maintaining national treasures such as Glacier National Park.

Repeat photography showing the retreat of the Grinnell glacier in Glacier National Park. The top photos were taken around 1940, and the bottom photos show the glacier six decades later. SOURCE: USGS (2008).
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