USGS ScienceSearch

Geology topics

Joanna Freeland

Publications and source records attributed to Joanna Freeland.

2 recordsLinked to original sources

Genetic analysis of North American Phragmites australis guides management approaches

Phragmites australis subsp. australis is an invasive and ecologically detrimental plant in multiple regions of North America. Its co-occurrence with the native subspecies, and multiple instances of hybridization, has created the need to differentiate Phragmites subspecies or haplotypes so that management can be appropriately targeted to the invader. We compiled a review of current genetic discrimination methods among the three Phragmites subspecies inhabiting the United States and Canada, and discussed how each method can contribute to control of the introduced subspecies while preserving the two endemic subspecies. We also discussed various control tools and the implications of Phragmites genetics for implementation. The Phragmites subspecies endemic to North America have environmental or infrastructure significance (e.g., habitat sustainability, biodiversity, storm surge and erosion protection). Thus, faster and more accurate differentiation among the endemic and introduced subspecies is needed. Additionally, more in-depth genetic information on Phragmites subspecies could support better management decisions, as well as the development of improved control treatments. This review highlights technologies and approaches currently available for genetic identification, recently collected genomic, transcriptomic and proteomic information, and implications for biological control and herbicide treatments.

Aquatic Botany

Typha (cattail) invasion in North American wetlands: Biology, regional problems, impacts, ecosystem services, and management

Typha is an iconic wetland plant found worldwide. Hybridization and anthropogenic disturbances have resulted in large increases in Typha abundance in wetland ecosystems throughout North America at a cost to native floral and faunal biodiversity. As demonstrated by three regional case studies, Typha is capable of rapidly colonizing habitats and forming monodominant vegetation stands due to traits such as robust size, rapid growth rate, and rhizomatic expansion. Increased nutrient inputs into wetlands and altered hydrologic regimes are among the principal anthropogenic drivers of Typha invasion. Typha is associated with a wide range of negative ecological impacts to wetland and agricultural systems, but also is linked with a variety of ecosystem services such as bioremediation and provisioning of biomass, as well as an assortment of traditional cultural uses. Numerous physical, chemical, and hydrologic control methods are used to manage invasive Typha, but results are inconsistent and multiple methods and repeated treatments often are required. While this review focuses on invasive Typha in North America, the literature cited comes from research on Typha and other invasive species from around the world. As such, many of the underlying concepts in this review are relevant to invasive species in other wetland ecosystems worldwide.

Wetlands