Freshwater Ecosystems
Freshwater ecosystems are vulnerable to climate change. Increases in water temperature and changes in seasonal patterns of water runoff could disturb fish habitat in lakes, streams, and wetlands. The New England/Mid-Atlantic regional projections (Moore et al., 1997) suggest warmer and drier conditions resulting in
- increases in annual average temperature ranging from 5-9°F (with the greatest increases occurring in autumn or winter),
- increases in rates of evaporation and evapotranspiration, resulting in about a 21 percent (in autumn) and 31 percent (in winter) reduction in annual stream flow in the southern and northern parts of the region,
- decreased snow cover, and
- possible decreases in the frequency but increases in the intensity of summer thunderstorms.
Freshwater ecosystems in the region have substantial diversity, enhancing their importance for recreational fishing as described in the left box. The region has 70 - 201 native freshwater species, and 12-80 mussel species. Habitat alteration, pollution, and non-native invasive species have placed from 46 - 71 percent of these mussel species at risk for loss in the region (Fisher et al., 2000).
The Impact of Climate Change on Recreational fishing in the Mid-Atlantic Region
Changes in warmth and seasonal characteristics have been identified as key for recreational fish vitality in the Northeastern United States. This especially is true for its higher-elevation streams in the mountainous Mid-Atlantic parts of the region. For example, bass and trout are some of the most popular recreational freshwater fish species found in the region. If stream water temperature increases (due to climate and ground water temperature changes), trout habitat will shrink in low elevations and low latitudes but bass habitat will increase. Brook trout is the least tolerant freshwater fish species to temperature fluctuations, so increases in stream water temperatures could cause their loss from many portions of the region. Even though the overall recreational fishing prospects are complex in a climate change scenario, increases in stream water temperature could result in a net loss in recreational fishing opportunities. Source: Fisher et. al. (2000)
Next: Terrestrial Ecosystems