Invasive Species

Weeds, Exotics or Invasives? : 

Weeds, Exotics or Invasives? What is a weed? Invasive species?

Weeds, Exotics or Invasives? : 

Weeds, Exotics or Invasives? Exotic or non-native: “Non-native invasive pest plant” http://dnr.metrokc.gov/wlr/lands/weeds/photos/kudzu_impact.jpg

Where do our non-native invasives plants come from? : 

Where do our non-native invasives plants come from? From a different ?

What are biotic provinces? : 

What are biotic provinces? Areas on the earth that have evolutionarily related organisms because of geographic isolation Animals are more related to other animals in their biotic province than to animals that fill the same niche in a different province Large mammal herbivores: Bison and pronghorn antelope in North America giraffes and antelopes in Africa large rodents like capybara in S. America kangaroo in Australia

Slide 5: 

In each major biome, certain animal or plant families dominate. Similar features evolve because of similar environments Thorns on some plants are modified leaves, on other plants thorns are modified branches Stem succulence in cacti (Americas) and euphorbias (Africa) “Convergent evolution” “ecological equivalents”

Slide 6: 

Species introductions bring species that have not evolved and adapted in the presence of the native species. Why is this significant?

Slide 7: 

“Competitive exclusion principle”: Two species that have exactly the same requirements (niches) cannot coexist in the same habitat. Native species have adapted to this through niche partitioning.

Do all species introductions lead to invasive species? : 

Do all species introductions lead to invasive species?

Biomes : 

Biomes A group of similar ecosystems Desert, tropical rain forest, grassland Determined by physical factors precipitation temperature sunlight & seasons

Slide 10: 

Similar environments lead to the evolution of organisms similar in form and function (but not necessarily genetic heritage) Similar biomes generally share same physiognomy (shape of vegetation) or vegetation characteristics “Convergent evolution”

Effects of latitude and precipitation : 

Latitude affects temperature Within a band of latitude, changes in aridity (precipitation) affects vegetation type Effects of latitude and precipitation

Similar changes in vegetation with altitude as with latitude : 

Similar changes in vegetation with altitude as with latitude

Slide 13: 

Deserts

Temperate Grassland : 

Temperate Grassland

Moving species around : 

Moving species around Local moves are less harmful than global moves. Less likely to be harmful if you move a species within its biotic province Moving a species into the same biome in a different biotic province is likely to be harmful.

What makes a species more likely to be invasive? : 

What makes a species more likely to be invasive? perennial germination in wide range of physical conditions grows quickly flowers early self-compatible produces many seeds which disperse widely reproduces vegetatively good competitor Few species will have ALL of these characteristics Having these characteristics does not mean a species is a successful invader

Slide 17: 

What makes a place more likely to be invaded?

Slide 18: 

If it has high native species richness Islands have more than mainlands Temperate agricultural areas and urban areas Nature reserves had less than non-reserves The larger the area, the more invasives What makes a place more likely to be invaded?

Effects : 

Effects Economic cost $97 billion/year cost to the U.S. economy crop losses, reduced grazing potential, weed control costs Leafy spurge (Euphorbia esula) introduced in Minnesota with oats shipment currently ~ 2.5 million acres infested in Canada & U.S. invades rangelands forage yield reductions of 10-100%

Effects : 

Effects Decreases Diversity decreases species richness by out-competing natives Miconia (Miconia calvescens) spread in Tahiti from Papeari Botanical Gardens, 1937 now invaded 70% Tahitian forests, with 25% dense monospecific stands 70-100 plant species threatened (35-45 endemics)

Invasive species and diversity : 

Invasive species and diversity Brown tree snake

Slide 22: 

Fritts, T. H.and G. H. Rodda. 1998. Annual Review of Ecology & Systematics 29:113-141.

Effects : 

Effects Ecosystem function may change primary production, nutrient cycling, water consumption Myrica Faya Invasive in Hawaii N fixing tree  alters N dynamics N inputs mostly from Myrica in some communities since volcanic soils are N-poor Hawaii the “exotic invasive capital of the world” species more susceptible to invasives: 1200 species, 90% endemic humans have added ~4600 species

Effects : 

Effects Altered fire regimes Can either promote fire or suppress fire Cheatgrass (Bromus tectorum) Provides fine flashy fuels in arid ecosystem it invades Fires ignite and carry well Comes back VERY well after fire Increases the frequency of fires

Saltcedar (Tamarix spp.) : 

Saltcedar (Tamarix spp.) From Eurasia sold in 1850’s for erosion control on stream banks 1 million acres in U.S. southwest outcompetes native riparian cottonwood-willow forests decreases diversity of birds, small mammals, invertebrates Changes the functioning of riparian zones

Invasives in Colorado : 

Invasives in Colorado Costs Over 1 million acres infested in Colorado > $10 million per year in lost productivity, weed control Worst of them according to state weed board Canada thistle (Cirsium arvense) Diffuse knapweed (Centaurea diffusa) Field bindweed (Convolvulus arvensis) Hoary cress (Cardaria draba) Jointed goatgrass (Aegilops cylindrica) Leafy spurge (Euphorbia esula) Musk thistle (Carduus nutans) Russian knapweed (Centaurea repens) Spotted knapweed (Centaurea maculosa) Yellow toadflax (Linaria vulgaris)

State noxious weed list : 

State noxious weed list African rue (Peganum harmala) Black henbane (Hyoscyamus niger) Black knapweed (Centaurea nigra) Black nightshade (Solanum nigrum) Blue mustard (Chorispora tenella) Bouncingbet (Saponaria officinalis) Bull thistle (Cirsium vulgare) Camelthorn (Alhagi pseudalhagi) Canada thistle (Cirsium arvense) Chicory (Cichorium intybus) Chinese clematis (Clematis orientalis) Coast tarweed (Madia sativa) Common burdock (Arctium minus) Common groundsel (Senecio vulgaris) Common mullein (Verbascum thapsus) Common St. Johnswort (Hypericum perforatum) Common tansy (Tanacetum vulgare) Common teasel (Dipsacus fullonum) Cypress spurge (Euphorbia cyparissias) Dalmatian toadflax (Linaria dalmatica) Dame's rocket (Hesperis matronalis) Diffuse knapweed (Centaurea diffusa) Downy brome (Bromus tectorum) Dyer's woad (Isatis tinctoria) Field bindweed (Convolvulus arvensis) Flixweed (Descurainia sophia) Green foxtail (Setaria viridis) Hairy nightshade (Solanum sarrachoides) Halogeton (Halogeton glomeratus) Hoary cress (Cardaria draba) Houndstongue (Cynoglossum officinale) Johnsongrass (Sorghum halepense) Jointed goatgrass (Aegilops cylindrica) Kochia (Kochia scoparia) Leafy spurge (Euphorbia esula) Longspine sandbur (Cenchrus longispinus) Mayweed chamomile (Anthemis cotula) Mediterranean sage (Salvia aethiopis) Musk thistle (Carduus nutans) Myrtle spurge (Euphorbia myrsinites) Oxeye daisy (Chrysanthemum leucanthemum) Perennial pepperweed (Lepidium latifolium) Plumeless thistle (Carduus acanthoides) Poison hemlock (Conium maculatum) Puncturevine (Tribulus terrestris) Purple loosestrife (Lythrum salicaria) Quackgrass (Elytrigia repens) Redstem filaree (Erodium cicutarium) Rush skeletonweed (Chondrilla juncea) Russian knapweed (Centaurea repens) Russian thistle (Salsola collina) Russian thistle (Salsola iberica) Saltcedar (Tamarix parviflora) Saltcedar (Tamarix ramosissima) Scentless chamomile (Anthemis arvensis) Scotch thistle (Onopordum acanthium) Scotch thistle (Onopordum tauricum) Spotted knapweed (Centaurea maculosa) Squarrose knapweed (Centaurea virgata) Sulfur cinquefoil (Potentilla recta) Velvetleaf (Abutilon theophrasti) Wild caraway (Carum carvi) Wild mustard (Brassica kaber) Wild proso millet (Panicum miliaceum) Yellow foxtail (Setaria glauca) Yellow nutsedge (Cyperus esculentus) Yellow starthistle (Centaurea solstitialis) Yellow toadflax (Linaria vulgaris)

Slide 30: 

ANIMALS. Introduced into the Colorado River as a sport fish, the flathead catfish is wiping out native fish populations. The zebra mussel clogs utility water intake pipes in the Great Lakes and the Mississippi Basin. The rosy wolfsnail, brought to Hawaii to control another exotic snail, has gobbled native snails to near extinction. The green crab, accidentally introduced to San Francisco Bay, threatens West Coast oysters and Dungeness crabs. Australia's brown tree snake has wiped out virtually all bird species in Guam and is now in Hawaii. The balsam wooly adelgid, an aphidlike insect, has wiped out nearly three fourths of the South's spruce-fir forests. PLANTS. An ornamental with bright flowers, purple loosestrife is clogging Northeast and Midwest wetlands. Tamarisk, prized for wood, shade and erosion control, is sucking up precious groundwater in the Southwest. Leafy spurge infests 3 million acres of western grazing land and crowds out native grasses. Hydrilla, which can grow 10 inches a day, is clogging Florida's waterways. Chinese tallow, a tree planted to start a Gulf Coast soap industry, prevents growth of native vegetation. In Hawaii, the giant leaves of miconia block sunlight that other plants need to survive. (US News and World Report 10/28/96, p. 12)