Talk outline. Invasive Species and Roads. Invasive Species. Why is this important? Kudzu. Zebra mussels

Transcription

1 Talk outline Invasive Species and Roads Invasive species introduction How roads affect invasions Managing invasive species Discussion about impacts of invasives Talk will primarily focus on invasive plants Invasive Species Species that, after they have been moved from their native habitat to a new location, spread on their own and cause ecological or economic problems This combines aspects of other common terms Non-native, exotic, non-indigenous Noxious, pest Why is this important? Invasive species: Cause economic damage Pimentel et al 2000,2005 Reduce native diversity Higgins et al 1999 Alter ecosystem properties Gordon 1998 Are second only to habitat destruction as a major cause of species extinction Bernd Blossey Wilcove et al 1988 ag.arizona.edu Kudzu Zebra mussels biology.usgs.gov/luhna/chap4.html

2 Dutch elm disease Gypsy moth photos1.blogger.com/img/141/4313/1024/dutch%2.. Microstegium vimineum Japanese stiltgrass found in roadsides, forests, riparian areas, lawns, pastures, ditches, Interferes with forest regeneration Oswalt 2004 Reduces native diversity Oswalt 2004 Alters soil characteristics and microbial function Ehrenfeld et al 2001, Kourtev et al 2002 What makes a successful invader? Produce many offspring Short generation time Good dispersal ability Lack of natural enemies What kind of habitats are likely to be invaded? DISTURBED Lots of available resources Nutrients Space Roadsides are great environments for many invasive plants The invasion process Native Elsewhere Survival in Transport Establish in New Areas Lag Period Spread Ecological Impact Human impact Sakai et al. 2001

3 How roads affect invasions Alter habitat Move propagules such as seeds Critical habitat alterations What kinds of road management activities might change the habitat to facilitate invasion? Graders: disturbance Not revegetating: easy invasive establishment Especially in ditches Habitat alterations: daylighting Roads cause propagule movement Road maintenance Grading Mowing Snowplowing Vehicle traffic Cars, bicycles, off-road vehicles Foot traffic Bringing in infested material Gravel, fill containing seeds A photograph of my boot exiting a study site. Covered with Taraxicum and Stellaria seeds, my boots serve as an effective seed dispersal agent

4 Roads serve as a corridor for invasive movement Current research Quantify the spread of seeds along roads during grading Quantify movement of seeds off roads into the forest by culverts Model the resulting spread of Microstegium through forests Dispersal distances 60 # seeds observed Distance along road (m) Furthest distance found so far: 205 m Movement off of roads: water movement Dirt and gravel roads Maintenance such as grading has particularly significant potential for spreading species What else makes them special for invasives or their management?

5 Prevention Managing invasive species Clean equipment between sites Use weed-free material Gravel, dirt Keep weed-infested material separate Use appropriate species when revegetating Treat invasive species like a disease Results Quantify the amount of propagules transported on three types of military vehicles (tracked, tactical wheeled and civilian pattern) (MSU Lead, ). 53 species detected at one site 40 species and still being evaluated at another Ranges from <1 to ~8 seeds/km/vehicle How to wash vehicles? Evaluate the potential of different military (tracked, tactical wheeled and civilian pattern) vehicles for transporting nonindigenous plant species propagules using 5 different vehicle washing units. (USFS Lead. 2007) Evaluated 5 systems run by contractors Used lightweight pickups, fire engines, bulldozer Limited time to 5 min for wheeled vehicles, 1 hour for bulldozer 77% average removal of debris best case scenario USFS Technical Report published September

6 Early detection: Need to know what species it is Very specific to a location find out what species are of concern in your area Watch List for Pennsylvania Butterfly bush, Climbing euonymus, Japanese hops, Hydrilla, Miscanthus, Japanese pachysandra, Corktrees,Rough bluegrass, Bee-bee tree, Siebold viburnum, Linden viburnum, Doublefile viburnum, Black swallow-wort, Japanese wisteria, Chinese wisteria,yucca Japanese hops Annual vine Seeds dispersed by water and wind Outcompete other vegetation Photo: Leslie J. Mehrhoff, University of Connecticut, IPANE, Black swallow-wort Perennial vine Reproduces by seed and by underground stems Coming southward from New York Competes with other plants, may interfere with Monarch butterflies More established species Garlic mustard (Allaria petiolata) Found in disturbed areas, including roadsides Displaces native vegetation Not eaten by deer Spreads into forest interior Japanese knotweed (Polygonum cuspidatum) Can tolerate deep shade, high salinity, drought Forms dense thickets that alter ecosystems, suppress native species

7 Found in a wide range of habitats Also dispersed by birds Grows aggressively May harm nesting success Multiflora rose (Rosa multiflora) Tree of heaven (Ailanthus altissima) Widely distributed Can damage sewers Establishes dense stands that inhibit growth of other species Secretes chemicals that inhibit growth of other species To learn more about invasives Northeastern Weed Science Society Shortcourse (taking place right now) Chemical Mechanical Both Decide on appropriate management Make sure to be selective! Chemical control Choice of herbicide depends on Which chemical is effective against the species How many applications required Would other species be affected Proximity to water Cost Federal and state regulations Mechanical control Mowing, tilling, burning Important points Try to minimize soil disturbance Mow before seeds are produced Don t mow after seed production Make sure to clean equipment

8 Establishing invasion resistant communities Critical to revegetate areas after management otherwise more invaders will come in Important to manage early!! Eradication difficult once species widely established Small group discussion (2-4 people) As road managers, what problems to invasive plants create for you? Acknowledgements The project was supported by the National Research Initiative of the USDA Cooperative State Research, Education and Extension Service, grant number How do you think road maintenance or construction activities could be modified to mitigate ecological and economic problems?