United States Department of Agriculture March 2015 Number 8 Newsletter Editors Dean Pearson, Research Ecologist USDA Forest Service—RMRS From the Editors Missoula, Montana 59801 Phone: 406-542-4159 This newsletter is designed to keep a common theme in many ecosystems Email: [email protected] managers and other users up-to-date with throughout the United States, including in http://www.fs.fed.us/rm/invasive-species/ recently completed and ongoing research places established specifically to protect by RMRS scientists, as well as to highlight native species and communities. Although Yvette Ortega, Ecologist breaking news related to invasive species the exact number of plants introduced USDA Forest Service—RMRS Missoula, Montana 59801 issues. The newsletter is produced by into the United States is unknown, Phone: 406-542-4152 the RMRS Invasive Species Working published estimates range from 4,000 to Email: [email protected] Group (ISWG), a core group of scientists 5,000 species. Fortunately, only a small who volunteer to disseminate RMRS proportion of species identified as exotic Jack Butler, Research Ecologist invasive species science to managers appear to adversely impact native species, USDA Forest Service—RMRS and the public through this newsletter, the communities, and ecosystems. However, Rapid City, South Dakota 57702 website, and periodic white papers. All of the larger portion of exotic species that are Phone: 605-716-2160 our products, including past issues of the currently considered benign represents Email: [email protected] newsletters and lists of publications, can a pool of potentially damaging species be found online at: http://www.fs.fed.us/rm/ should environmental conditions shift in invasive-species/. their favor, as via climate change. The Invasive Species Working Group Early Detection section of this newsletter Team Leader In this issue, we highlight the importance highlights the need to be ever vigilant Dean Pearson, Research Ecologist of early detection and rapid response regarding entry of new species, even USDA Forest Service—RMRS as applied to new invader incidents for those that appear benign. meadow hawkweed, medusahead, and rush skeletonweed. Exotic plants are now USDA Forest Service—RMRS Production Publishing Services USDA Forest Service—RMRS Meadow hawkweed infestation (photo credit: Linda Wilson, University of Idaho, Bugwood.org). Black-capped chickadee (photo credit: K. Zeiber Nature Photographs). 1 Research Notes A Spectral Library of Native and Invasive Species from a Post-Fire Environment By Sarah Lewis-Scholes (sarahlewis@ fs.fed.us), Andrew Hudak (ahudak@ The reflectance spectra of prickly lettuce in red and field fs.fed.us), and Pete Robichaud bindweed in green. Each plant ([email protected]), Forestry species has a unique spectral Sciences Laboratory, Moscow, Idaho signature. Managers were very concerned about weed spread following the 2005 School Fire that burned 50,000 acres of state, pri- vate and Umatilla National Forest lands in southeast Washington. Non-native plants, including invasive and noxious species, often increase after fire following reduc- tions in native plant and tree canopy cover and density. Remote sensing is often used after wildfires to monitor and map changes in soil and vegetation conditions. Toward improving this tool, RMRS and Univer- sity of Idaho researchers conducted a pilot study to collect unique plant “spectral re- Right: Sarah Lewis-Scholes samples the reflectance spectra of prickly flectance signatures” that can be combined lettuce (Lactuca serriola), which is with high-resolution remote imagery in or- non-native to eastern Washington. der to track weed spread. Penelope Morgan and Leigh Lentile collected these detailed Bottom: Collecting the unique reflectance spectra of field bindweed signatures for more than 70 species, in- (Convolvulus arvensis), a Class C cluding 11 classified as noxious in the state noxious weed in eastern Washington. of Washington. The goal was to use the reflectance signatures, or “endmembers,” together with high-resolution, Quickbird satellite imagery to map weed spread after the fire. Over the course of six summers of field sampling, however, non-native spe- cies were found at low cover (maximum 2% plot cover) in fewer than 20% of the high severity burn plots and were absent altogether in unburned plots. The lack of substantial weed cover following this par- ticular fire kept researchers from detecting these plants using collected signatures in the remotely sensed imagery. However, the library of compiled reflectance spectra data can be used by other managers and scientists for similar remote sensing image analyses on other fires, particularly when paired with high-resolution, hyperspectral imagery that has many more channels than Quickbird. The spectral library may be accessed at: https://www.frames.gov/part- ner-sites/assessing-burn-severity/spectral/ spectral-library-eastern-washington/. 2 Disease Resistance Gene white pine blister rust and its inheritance Discovered in Limber Pine in limber pine. The researchers report that 14% of the 105 tested limber pine seed By: Anna Schoettle (aschoettle@ lots show segregation of a disease-free fs.fed.us), RMRS Forestry Sciences trait consistent with inheritance by a single Laboratory, Fort Collins, Colorado dominant gene, which they name “Cr4.” Limber pine seedlings with the dominant Limber pine (Pinus flexilis) is being resistant allele Cr4 remain disease-free af- threatened by the lethal non-native dis- ter artificial inoculation with the white pine ease white pine blister rust, increasing blister rust fungus. The average frequency bark beetle pressure, and climate change of the Cr4 allele across healthy and re- in mountain environments. Tree line cently invaded populations in the southern ecosystems dominated by limber pine Rocky Mountains was unexpectedly high are ecologically valuable for watershed (5.0%; ranging from 0 to 13.9%). This re- protection and diversity. Consequently, search suggests that Cr4 is not a product limber pine is of conservation concern in of a recent mutation and may confer other the southern Rocky Mountains. In a recent adaptive benefits against other abiotic or publication in the journal Phytopathology, biotic stress factors. For more information Forest Service researchers report on the on this research, see Schoettle and others first of a series of studies using seed lots (2014) in the Recent Publications section. from individual seed trees (genetic fami- Cover of the February 2014 issue of Phytopathology. Depicted in the cover image: lies) to examine complete resistance to premature senescence of infected needles is an early indication of this genetic resistance. Genetic Diversity and Population gene flow in sickleweed populations of Structure of Sickleweed (Falcaria the upper Midwest, probably as a result of human mediated propagule dispersal, that vulgaris) have now resulted in higher genetic diver- sity. The ability of sickleweed populations By: Jack Butler ([email protected]), RMRS Forest & Grassland Research to expand vegetatively by root sprouting Laboratory, Rapid City, South Dakota can foster rapid selection of such adapted genotypes. Evolutionary changes that Genetic analysis of recently introduced have occurred in sickleweed since its es- plants can provide valuable insight into tablishment and expansion could be used their potential to be invasive and assist in to prioritize management strategies that developing management strategies. In this reduce gene flow among genetic clusters study, students and faculty at South Dakota or chlorotypes. For more information see State University collaborated with RMRS Piya and Nepal (2013) and Piya and others scientists to use chloroplast and nuclear (2014) in the Recent Publications section. Heavy infestation of sickleweed on the Fort DNA markers to (1) study the genetic Pierre National Grasslands (South Dakota). diversity and structure of upper Midwest United States populations of sickleweed, and (2) determine whether sickleweed populations in the United States were established from a single or multiple intro- ductions. Results of the study indicated a positive correlation between genetic diver- sity (higher number of alleles and higher observed and expected heterozygosity) and population size. Several studies have shown that high genetic diversity is a characteristic of many invasive plant pop- The coarsely toothed leaf is responsible for ulations. Further analyses showed three giving sickleweed its common name. distinct genetic clusters that are distributed without any geographic pattern, suggest- Graduate student Sarbottam Piya (left) studies ing multiple introductions of sickleweed the genetic diversity of sickleweed, an exotic plant in the northern Great Plains. Overall, the species recently introduced into the Northern Great Plains (photo credit: Madav Nepal). study indicates multiple introductions and 3 Who Gets the Novel Resource Prize? Black-capped chickadee showing By: Yvette Ortega ([email protected]. color bands used to track individuals us) and Dean Pearson (dpearson@ (photo credit: K. Zeiber Nature fs.fed.us), RMRS Forestry Sciences Photographs). Laboratory, Missoula, Montana Exotic species are infamous for their strong negative effects on native species, but less appreciated is the fact that such Ortega and University of Montana invaders can also have strong positive ef- researchers Leigh Greenwood and fects. For example, exotic organisms can Ray Callaway studied the foraging provide