Tulalip Tribes Invasive Species Inventory

The biggest challenge in managing invasive species is their fast dispersal combined with the lack of capacity to detect and respond to infestations. Once a threshold is passed in an invasion, eradication of becomes virtually impossible and only management actions can be undertaken. It is important for the tribal community to have access to up-to-date information on invasive species including, but not limited to, the effects of invasive species on the ecosystem and treatment of invasive species. The degradation of the environment caused by invasive species directly impacts the availability of Treaty Reserved Resources that the Tribes have subsisted on since time immemorial.

Invasive plant species are detrimental to natural resources, harming property and biodiversity. The most common problems with invasive plant species are:

• Loss of habitat for birds, fish, and other plants
• Increased erosion
• Water quality degradation
• Loss of coniferous canopy
• Creating single-species stands of plants

In addition to changing plant communities, some invasive plant species can change the chemistry and composition of soils – permanently changing the ability of the ecosystem to regenerate to pre-disturbance conditions including ecosystem processes.  

All of the mechanisms that make invasive species so harmful, are the same that make them so successful in urban and disturbed areas. Invasive plant species often establish and spread along road networks and other human corridors of travel, cleared areas, and developed/disturbed areas. Humans are also the most likely method to disperse an invasive species, either intentionally such as for landscaping or unintentionally such as in boat ballast water. Invasive plant species spread fast (usually via two or more reproductive strategies such as by seed and through vegetative fragments such as new plants sprouting from a small piece of root), are generalists, and can persist in a wide range of soil and water conditions.  This makes invasive plant species very likely to get to and take over areas whereas more specialized native species need time and space to establish communities.

(Carcinus maenas)

The European Green Crab (Green Crab) is an invasive species which is believed to have reached to the Pacific Coast recently through imported seafood products. Able to adapt to a wide variety of environments, these crabs have established persistent invasive populations around the globe. Green crabs pose a threat to species in the Salish Sea through predation, competition for resources, and habitat modification. Species at risk include Dungeness crabs, oysters, mussels, clams, and other organisms that are important for ecosystem health. Even salmon may be threatened by green crabs because they can degrade the salt marshes and eelgrass beds which juvenile salmon rely on for rearing habitat.

The Tulalip Tribes Green Crab monitoring program was developed in response to known invasions both to the north and west of the Tulalip Tribes Reservation. The European Green Crab Threat Map is based on the general areas where green crabs are currently most prevalent. Geographic and oceanographic barriers likely influence threat, but are not represented in this map.

Four sites of potential green crab habitat were monitored from April through September, 2022. The site furthest to the east was also monitored in 2023. Monitoring sites are indicated by yellow dots. As of September 2023, no green crabs have been observed at any of the Tulalip Tribes Green Crab Monitoring sites.

The goal of the Tulalip Tribes Green Crab Monitoring program is to detect the arrival of green crab within the Tulalip Tribes fisheries areas as early as possible. Early detection allows our shellfish and fisheries managers to take action before a green crab population becomes established and causes a significant economic impact.

The Tulalip Tribes Natural Resources Department observed bull frogs as a bycatch during fish sampling. Therefore, the majority of bull frog encounters have been as tadpoles and not as adult frogs. However, both tadpoles and adults compete with native species for food and living space.

Bull frog tadpoles (Rana catesbeiana) have a nearly bottomless stomachs. Their preferred foods include not only algae and aquatic vegetation, but the eggs and the young of native species including fish, frogs, salamanders and turtles. Bull frog tadpoles compete with native species for both food and living space. They have also been observed to change the habitat in which they have become established, making it unlivable for native species.

When these tadpoles develop into frogs, their appetite only increases, as does the the food size they can consume. This causes the threat of bull frogs to native species to extend into older life stages. In addition, bull frogs often host a fungus (Batrachochytrium dendrobatidis) that can be deadly to native frogs.