Rising Temperatures and Climate Change

Scientists have correctly predicted that the average annual air temperature in New Hampshire would rise, leading to more days above 90°F. Warmer summers increase the temperatures in some coldwater streams.  Additionally, warmer winters will mean reduced snowfall, which shorten the winter season and decrease the snowpack. Growing seasons are extended with fewer days of frost, causing changes in tree species. The lack of snowpack leads to freezing soils which damage tree roots and kill vegetation, causing habitats to degrade.

How Rising Temperatures Affect Wildlife

Coldwater fish species, such as brook trout and salmon, cannot tolerate sustained temperatures above 65°F. Warmer water also holds less dissolved oxygen. As climate change causes water to warm, these species will have to move to streams with cooler water temperatures. If such refuge areas are not available or are cut off due to barriers such as inadequate culverts, these fish will not survive and will be replaced by warmwater species such as yellow perch and smallmouth bass. Two of New Hampshire’s endangered freshwater mussel species, dwarf wedgemussel and brook floater, use coldwater fish as a host so fewer fish will affect the mussels’ survival. Mussels are important because they are an indicator of water quality and river health.

Some wildlife in New Hampshire at the southern limit of their range may also be directly affected by rising temperatures. Warmer weather causes moose to show symptoms of heat stress, which causes their respiration and heart rates to increase. They seek shade and cooling winds or cool water, and they bed down and eventually cease foraging, increasing their risk of mortality. Shorter winters are also allowing winter ticks to thrive, which is a parasite that is decimating the moose herd.

What NH Fish and Game Is Doing in Response to Rising Temperatures

The Fisheries Division works with many partners to monitor and manage coldwater habitat for trout, including advising landowners on establishing trees along rivers for shade and reduction of erosion of soil into the river itself. Biologists also work with towns to replace inadequate culverts with stream crossings that will allow trout passage to colder, higher elevation sections of the stream.

A multi-year study is under way in New Hampshire to learn more about threats facing the moose population, including winter ticks. The study began in 2014 and involves capturing and collaring moose to track their survival. According to the New Hampshire Game Management Plan, the Department will work with partners to monitor moose populations and to conserve, protect, and enhance moose habitat.

Another climate change-related marine effort is the protection of the North Atlantic right whale. NH Fish and Game is working with the lobster fishing industry to come up with options on methods to meet the Atlantic Large Whale Take Reduction Team’s consensus on reducing interactions with the whales to prevent serious injury and mortality. The North Atlantic right whale is the most endangered large whale species in the world and is protected under the Marine Mammal Protection Act and the Endangered Species Act. The population has been in decline since 2010, and this is attributed to both human-induced causes, such as fishing gear entanglements and collisions with ships, as well as low species birth rates. Also the warming of the waters in the Gulf of Maine is believed to be having an effect on the life cycle, phenology (biological cycles related to climate, such as bird migration and plant flowering), and distribution and abundance of the food sources of these whales.

Rising Temperatures and People

Trout and native mussels are often considered good environmental indicators because they are sensitive to water quality and habitat degradation. Anglers rank brook trout as one of their favorite species. In addition to the potential loss of our iconic species, such as moose, rising temperatures will challenge coldwater fisheries, reducing angler opportunity. However, warmwater fish species such as bass will do better, presenting continued opportunity for outdoor recreation. Black bear hibernation is sensitive to temperature as well, so we may see them out more often during the winter.

Taking Action

• Volunteer to work with your local schools to monitor water quality.
• Volunteer to help Fish and Game and other partners by participating in surveys.
• Educate yourself and share your understanding with friends and family about how climate change affects wildlife and habitats.   
• Start planning now for good ecological health and get involved in your local community by addressing potential climate change issues in your town or region.   
• Support and volunteer for environmental and conservation organizations that address climate change impacts to wildlife and habitats.
• Become a citizen scientist and help collect data on plants, wildlife, water, and weather.