Climate change affects more than temperature. Impacts include shifts in rainfall and storm patterns, catastrophic wildfires, and water shortages, as well as rising sea levels, loss of sea ice, ocean acidification, and coastal flooding and erosion. These changes are already having significant effects on fish, wildlife and plants here in the United States, necessitating new resource management approaches for climate adaptation.
Rapid warming may also begin to threaten the benefits natural systems provide to people and communities, creating new challenges for human health, infrastructure, agriculture, transportation, and energy supplies. Clean air and water, flood and erosion control, natural resource jobs and income, hunting, fishing, and wildlife-related recreation, and ultimately our quality of life are at risk.
The varied ecological impacts of climate change will affect fish, wildlife, and plants in diverse and sometimes unexpected ways. Some of the most common ecological changes currently being observed include:
Transforming habitats: Habitat modifications include the transformation of particular features such as sea ice and wetlands as well as the direct loss of coastal habitat due to sea level rise. Most affected will be species that are highly specialized or dependent upon particular ecological conditions or habitat features, such as polar bears tied to Arctic sea ice.
Shifts in timing: Another type of commonly documented ecological response is changes in the phenology or timing of life history events, such as breeding or flowering. In North America, some birds like tree swallows now begin egg-laying over a week earlier than in the past, which could mean young may hatch before insect food is plentiful for some species.
Rising temperatures: Rising average air and water temperatures associated with climate change directly affects many marine and terrestrial species, especially those with narrow thermal tolerances. For example, warming of even one degree Celsius may be enough to push some corals over their temperature limits.
Range shifting: Climatic conditions help determine where species are found. As the climate changes, the geographic ranges of many species may move as well, often toward cooler temperatures or to follow shifting habitats. In the United States, a number of butterfly species have shifted northward and contracted upward in elevation over the last century.
Spreading pests and disease: Climate change may also allow new pathogens, parasites, pest species, and wildlife diseases to flourish in new areas or to spread more rapidly. In the Rocky Mountains, warmer temperatures have allowed the mountain pine beetle to greatly increase in population and decimate vast areas of forestland.
In addition, every species will react to these impacts in different ways, leading to potential community disruption as plants and their pollinators or predators and their prey are "pulled apart."
Examples of climate impacts on fish, wildlife, and plants
- Waterfowl: Both conservationists and hunters worry that a warmer, drier climate will adversely affect the enormously productive prairie pothole ‘duck factories’ in Montana, North Dakota and Minnesota on which much of the nation’s waterfowl rely for nesting.
- Salmon: These species which require cold, fast-flowing streams and rivers to spawn are being affected by warming and by reduced stream flows caused by less snowmelt. Climate change will impact major commercial and recreational fishing industries, as well as indigenous cultures that depend on salmon for their traditional ceremonial and cultural practices.
- Lodgepole pine: Millions of acres of lodgepole pine and other trees have been killed across the West by an epidemic of mountain pine beetles. The reason: Warmer winters have enabled more beetles to survive the winter, while warmer summer temperatures have enabled the tiny insect to complete more generations per year and expand its range northward.
- Oysters: In 2007 and 2008, two major West Coast oyster hatcheries discovered that their oyster larvae were dying due to higher acidity in the water being pumped from the sea into their facilities. As the oceans absorb more CO2 from the air, the waters become more acidic, so the problem will escalate.
- Butterflies: Climate change has brought a mismatch between the life cycle of the Edith's checkerspot butterfly and the timing of the growth and flowering of the plants the caterpillars and adult butterflies depend on. That has caused the butterfly’s population to crash in some areas, especially those along the southern range.
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