Cattail (Typha) invasion in North American wetlands
Cattail (Typha) is a robust, emergent plant commonly found in wetland ecosystems worldwide. By producing large quantities of wind-dispersed seeds, cattail can colonize wetlands across landscapes, and its rapid growth rate, large size, and clonal expansion result in dense stands in a variety of aquatic ecosystems such as marshes, ponds, lakes, and along riverbanks. Cattail can also overtake disturbed areas with waterlogged soils such as roadside ditches, water retention areas, and fringes of stormwater collection ponds. Dense stands of cattail can impact local plant and animal life, biogeochemical cycling, and wetland hydrology, which in turn alter wetland functions and ecosystem services provided to society.
Cattail is often a natural part of healthy wetland ecosystems. However, over recent decades, human disturbances to natural water cycles and increased nutrient inputs to aquatic systems have led to a dramatic increase in the spatial coverage and abundance of cattail in North America. In addition, highly competitive nonnative and hybrid taxa have expanded and accelerated the spread of cattail. In the U.S., invasion of cattail has been particularly detrimental to native floral and faunal biodiversity around the Laurentian Great Lakes, the Prairie Pothole Region, and the Florida Everglades.
Because cattail invasion and expansion typically alter wetlands in undesirable ways, wetland managers often respond with targeted physical, chemical, and hydrologic management efforts. These efforts, however, may have short-lived or weak effects because of the resilient nature of the plant, combined with the difficulty of operating in aquatic environments. Despite the negative impacts of cattail invasion, the plant can be used to provide a variety of ecosystem services, which are beneficial to society. Cattail has shown promise for reducing pollutants in aquatic systems through bioremediation, and it can be used to produce biofuel material. Cattail also is associated with many traditional cultural uses.
Despite cattail’s widespread distribution, invasive characteristics, and impacts to wetland systems, a comprehensive review and synthesis of past and current research on cattail was lacking. To address this information gap, a diverse team of researchers from public and private institutions produced a paper, which summarizes 4 decades of research from more than 650 references, that was featured as a Mark Brinson Review in Wetlands (Bansal et al., 2019). The paper details the biology, distribution and spread, ecologic drivers of invasion, and management of cattail throughout North America. Additionally, the paper describes how monotypic stands of cattail can affect other flora and fauna of wetlands and details specific regions where cattail invasion is especially problematic. The paper also discusses beneficial aspects of cattail and provides examples of how people around the world use the plant. While the review specifically focuses on cattail, many of the underlying principles and concepts that are discussed are relevant to other invasive plant species in wetland ecosystems. In addition to the review, a USGS fact sheet (Bansal et al., 2020) and an animated video (https://www.usgs.gov/media/videos/importance-cattails-wetlands) were created that highlight the primary topics covered in the paper.
The paper, "Typha (cattail) invasion in North American wetlands: biology, regional problems, impacts, ecosystem services, and management” was published in Wetlands - Invited Mark Brinson Review.