Invasive Species Management Mountains Restoration Trust Joseph Curti, Project Manager
Mountains Restoration Trust Education - Cold Creek Docents and community based volunteer restoration projects Acquisition - 7000 acres preserved Restoration - 2000 acres restoration mrt@mountainstrust.org | (818)591-1701 | https://www.facebook.com/MountainsTrust/
My Background
Invasive Species - Overview “Invasive species are plants, animals, or pathogens that are non-native (or alien) to the ecosystem under consideration and whose introduction causes or is likely to cause harm.” - USDA ● Aggressive ● Environmental adaptability ● High fecundity (https://en.wikipedia.org/wiki/Arundo_donax#Invasive_species) (https://en.wikipedia.org/wiki/New_Zealand_mud_snail) (https://www.hylawerkgroep.be/jeroen/index.php?id=49)
Invasive Species in our project sites Mosquito fish - Gambusia affinis Largemouth Bass - Micropterus salmoides Bluegill - Lepomis macrochirus Gree Sunfish - Lepomis cyanellis Red Swamp Crayfish - Procambarus clarkii
Red Swamp Crayfish
Impacts on stream http://e-ecodb.bas.bg/rdb/en/vol3/10C2.html http://www.georgialifetraces.com/tag/crayfish/
Macrophyte Clipping ● Crayfish consumptively and non-consumptively clip macrophytes ● In lake studies of signal crayfish, biomass and richness of macrophytes reduced (Lodge and Lorman 2011) ● Can cause dramatic changes in light attenuation, temperature, flow, deposition of fine sediments, retention of coarse detritus, and available nutrients and oxygen in the water (Carpenter and Lodge 1986) http://e-ecodb.bas.bg/rdb/en/vol3/10C2.html
Crayfish Burrowing Behavior ● Burrowing and movement on streambed lead to resuspension of nutrients and sediment ● Resuspension of sediments can lead to poor water quality, decreased light penetration and decreased aquatic plant growth (Gherhardi 2007) ● Loss of fine sand particles can impact egg survival in gravel breeding salmonids (Gherhardi 2007) http://www.georgialifetraces.com/tag/crayfish/
Impact on Natives Crayfish holding treefrog tadpole
Impact on Natives Crayfish holding treefrog tadpole
Impact on Natives Crayfish holding treefrog tadpole
Effect of crayfish on California Newts Tail clipping from California Newt by crayfish (Davis et al 2017)
What we are doing Medea Creek Las Virgenes Creek 66,451 crayfish removed since 210,337 crayfish 2014 removed since 2014
Mechanical Trapping ● Trapping 7 days a week at two sites ● Traps are placed in pool or run features in stream after monitoring for two weeks ● Medea Creek ○ 1.5 miles ○ 274 traps ● Las Virgenes Creek ○ 1.6 miles ○ 667 traps Upper reaches cleared ○ ● Seasonal biological surveys ● Dynamic mountain streams
Total Crayfish Removed
Total Crayfish Removed
Total Crayfish Removed
Trapping Success Adult Newts in Malibu Creek Watershed Number of Newts
Trapping Success Egg Masses in Malibu Creek Watershed Number of Egg Masses
Trapping Success Newt Larvae in Malibu Creek Watershed Number of Newt Larvae
Water Quality Monitoring 1) Identify stream water quality in Medea and Las Virgenes Creeks before, during and after invasive Red Swamp crayfish removal measured in temperature, pH, dissolved oxygen, conductivity, and total dissolved solids. 2) Identify if water quality parameters have stabilized to pre-introduction thresholds using nearby non-invaded stream data or historic standards as comparisons and if stream conditions are suitable for future steelhead trout reintroduction.
Analyzing Trap Efficiency
Questions? Joseph Curti (209)628-3972 jcurti@mountainstrust.org
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