| Invasive species are any plant or animal that has been introduced to a new region outside of their natural range and have negative impacts on the native ecosystems. They have the potential to foul boat hulls and fishing equipment, destroy crab and salmon nurseries and kill large swaths of the forest, leading to decreased habitat and increased risk of fire and landslides across Chichagof Island. Invasive species are one of the leading causes of biodiversity loss, which can lead to impacts at all levels of the food chain and threaten food supplies for humans and animals alike. |
Primary Risks
THE RANGE OF SEVERAL INVASIVE SPECIES WILL LIKELY INCREASE DUE TO GLOBAL WARMING.
The overall number of invasive species is likely to increase by 36 percent by 2050, with invertebrates making the largest increase. While not all of that growth can be attributed to climate change (other major stressors include trade, tourism, and transportation), climate change will make species more vulnerable and worsen the damage new invasive species can cause.
INCREASED HUMAN TRAFFIC THROUGHOUT THE REGION WILL PROVIDE NEW OPPORTUNITIES FOR INVASIVES TO TRAVEL.
42 invasive species were detected on road surveys in 2007, primarily near town, heavily used recreation sites (Whitestone Harbor, Wukulook, Suntaheen), and near previously logged forest plots that had been reseeded with non-native plants. The survey also found that only 13 of the invasive species documented on Chichagof were also present on Kruzof and Baranof Islands, meaning there is a large potential to increase the number of invasive species present near Hoonah. Invasive species also have the possibility to spread new viruses; sweet rocket (Hesperis matronalis) has been documented near Juneau, Ketchikan and Wrangell and can host novel viruses that can infect local plants.
MARINE AND RIPARIAN (STREAM) AREAS ARE LIKELY TO FEEL THE BRUNT OF THE ISSUE.
European Green Crabs pose a large threat to eelgrass beds in the intertidal and shallow subtidal regions, which currently serve as critical habitat for salmon fry, shellfish and juvenile Dungeness crab. EGCs are well established on the coasts of California, Oregon, Washington and British Columbia, and were recently documented as far north as Metlakatla. Stream environments and their related salmon runs also face threats from a variety of invasive species. There are currently over 250 marine invasive species that have settled along the west coast of the lower 48, and while only 15 of them have made it to Alaska, the potential for future invasions is large. Marine species also have an easier time moving from one location to the next, due to their ability to hitch a ride on ships and broadcast spawn in water and allow their larvae to drift from island to island.
INVASIVE LAND ANIMALS ARE THRIVING AND WITH RELATIVELY FEW NATURAL PREDATORS, ARE EXPECTED TO CONTINUE DOING DAMAGE.
While the majority of invasive species documented thus far on Chichagof are plants, there are also several invasive mammals (red squirrels, American martens and feral house cats) established. Without many natural predators, those species are likely to continue breeding and have an ever-increasing effect on local wildlife.
RISING TEMPERATURES HAVE ALSO EXPANDED THE RANGE OF A VARIETY OF INSECTS AND MAKE THEIR ATTACKS LAST LONGER.
Defoliating insects, such as the black-headed budworm, are a natural part of the Tongass, but can intensify climate risks such as droughts and landslides. If trees have already lost many of their needles due to budworms, it doesn’t take as heavy of a drought to inflict damage, and if trees are killed by hot weather or bugs, the lack of roots can increase the risk of landslides due to heavy rain.
Adaptation Strategies
SHORT-TERM GOALS:
1.1: Continue and expand monitoring programs for both extant and novel invasive species
1.2: Continue management at common recreational sites to limit the spread of invasive species.
1.3: Expand youth opportunities for invasive species management and community educational programs to help residents avoid accidentally introducing invasive species into the area.
1.4: Install boot brush stations at key locations throughout Hoonah and the broader Chichagof Island to prevent the spread of invasive species by foot traffic
1.5: Educate the community on the relationship between invasive species and increasing water temperatures and ocean acidification
MID-TERM GOALS:
2.1: Introduce and support climate-resilient native species
2.2: Conduct rapid response when new species are detected
2.3: Identify and protect particularly vulnerable native species
2.4: Invest in and develop kelp cultivation projects to improve marine habitats and biodiversity
LONG-TERM GOALS: 3.1: Collaborate with tribal, state and federal partners to develop invasive species monitoring programs and minimize their spread and impact.