Controlling Invasive Grass
Grasslands are among the world’s most endangered ecosystems. Unfortunately, they are also among the most unappreciated, partially because of what we can’t see since up to 80% of the biomass of a grassland is underground.
Grasses have deep fibrous roots which store carbon and help make these ecosystems resilient to fire and grazing. Here in the Sky Islands our grasslands support hundreds of species from endemic plants, migratory birds and threatened mammals like pronghorn and black-tailed prairie dogs. However, invasive plants pose one of the biggest threats to our Sky Island grasslands and the species that call them home.
Invasive species are introduced nonnative species that can take over ecosystems reducing the diversity of native plant and animal species. A particularly aggressive species of invasive grass called Yellow bluestem has started spreading throughout Southeastern AZ along roadsides and across rangelands, converting diverse grasslands to invasive monocultures.
This species has been documented in small populations in the Sonoita-Elgin grasslands. With support from the Arizona Department of Forest and Fire Management BRN will lead a collaborative effort in collaboration with the Appleton-Whittell Research Ranch, the Babacomari Ranch and the Tucson Audubon Society. This cooperative effort is aimed at controlling this invasive grass on 21,000 acres of mixed grassland habitat directly adjacent to the Las Cienegas National Conservation Area and Coronado National Forest.
Revegetating with native plants to keep invasive species at bay.
Because seeds embedded in pellets have high soil contact and are protected from seed predation by insects and rodents, they require minimal soil disturbance. Also, these seeds remain on site until heavy rains arrive with the monsoon, which wets up the clay and allow seeds to germinate while the soil is moist. We are grateful for the support of AZ Forest and Fire Management and look forward to working with our nonprofit and private partners to control this invasive grass and restore diverse native species to our local Sky Island grassland.
Contact Tess Wagner, BRN Restoration Program Manager with questions about this project. |
While this species has been found in small, relatively controllable patches for over a decade it has recently begun to spread to new places and can be seen along many roads and within the grasslands. With our partners we will monitor and map the extent of invasive grass species across the 21,000 acres, repeatedly treat invaded areas and facilitate the establishment of native species in treated areas.
Revegetating treated areas with native plants helps keep invasive species from returning and speeds the recovery of the grassland. To improve the success of the reseeding efforts we will use pelletized seeds, seeds added to a mixture of clay, high-nutrient soil or compost and water. Seed pellets are formed mechanically in the cement mixer and by hand and dried. 
Pelletized seeds are protected from seed predation, require minimal soil disturbance and help seeds germinate.
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THANK YOU TO OUR PROJECT PARTNERS:
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