lecture 08

lecture 08 - 2/10/11 Invasive Plants BTNY 304 Some...

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Unformatted text preview: 2/10/11 Invasive Plants BTNY 304 Some photographs were taken off various websites and are intended for instruc?onal purposes only WEED: a plant that interferes with the growth of desirable plants (compe<<ve) and is unusually persistent and pernicious. It nega<vely impacts human ac<vity and as such is undesirable. INVASIVE PLANT: a non ­indigenous species or strain that becomes established in natural plant communi<es and wild areas, replacing na<ve vegeta<on Similari<es between Agricultural Weeds and Invasive Plants •  High reproduc?ve rates •  Rapid dispersal and establishment •  Adaptability •  Lack of pests •  Some cross ­over species (i.e. Canada thistle, many pasture/range weeds are invasive) 1 2/10/11 Differences between Agricultural Weeds and Invasive Plants Agricultural Weeds: •  Disturbance dependent •  Easily dis<nguishable from crop •  Usually controlled by <llage and/or broadcast herbicides •  Rarely are beneficial or inten<onally planted Invasive Plants: •  OOen invading rela<vely undisturbed habitats •  OOen overlooked or not easily iden<fied in diverse natural areas •  Control op<ons much more limited due to presence of na<ve species and need to minimize disturbance •  May be inten<onally planted and have beneficial uses •  Very liTle funding for controls or research Invasive Plants in Indiana Bicolor lespedeza, Creeping Jenny, Japanese s<lt grass, Purple winter creeper Black alder, Common privet, Kudzu, Sericea lespedeza, Black locust, Common reed, Maiden grass, Siberian elm, glossy Buckthorn, Crown vetch, Mul<flora rose, Smooth brome, common Buckthorn, Dame's rocket, Norway apple, Star of Bethlehem, Bush honeysuckle, Garlic mustard, Oriental biTersweet, Tall fescue, Canada thistle, Highbush cranberry, Periwinkle, Tree of heaven, Creeping Charlie, Japanese hops, Purple loosestrife, White mulberry Species that are able to grow under a broad range of light, moisture or other environmental condi<ons are referred to as exhibi<ng plas<city, and are more likely to be successful invaders into new habitats. 2 2/10/11 Invasive species impede natural ecosystems by becoming dominant and changing the type of vegeta<on present in that ecosystem. Invasive trees and shrubs can change grasslands into forests Invasive grasses can change tree and shrub ecosystems into grasslands Large ­seeded woody perennials like hardwood trees are limited by aggressive grasses that prevent the establishment of the seedlings of the woody species. Reduced light at the soil surface Reduced photosynthesis Decrease surface temperature Competes for water and nutrients Creates dense liTer layers that prevents germina<on and survival of natural species Aggressive shiOs in species due to an invasive plant can alter the way the original ecosystem func<ons in terms of water cycling Soil characteris<cs Fire frequency Plant and animal community structure 3 2/10/11 All invasive species change their environment in some way, but approximately 10% of the invasive species are considered to be Transformer Species. Transformer Species are invasive species that change Character Condi<on Form Nature of a natural ecosystem in a way that harms both plants and animals that depend on the natural ecosystem to survive. Characteris<cs of Invasive Species Excessive use of water Saltcedar in the western states uses 35% more water than the na<ve species Draws down the water table Lowers the flow of waterways and increases sedimenta<on Aggressive growth Kudzu Giant reed Smothering of na<ve aqua<c vegeta<on by floa<ng invasive species Water hyacinth forms a solid layer over water surface Prevents light from reaching underwater plants and algae Loss of photosynthesis reduces oxygen levels causing harm or death to fish and other aqua<c wildlife Fire promo<on Downy brome, in the Great Basin desert and in grassland areas once dominated by perennial grasses, is now dominate. This short ­lived grass dies in the summer and leaves a mat of dry vegeta<on between na<ve plants that provide fuel for frequent fires. The less fire ­tolerant bunch grasses and shrubs in the area have almost totally been replaced by downy brome. Two Main Impacts of Invasive Species Loss of Plant Diversity – from a mix of na<ve plant species to a monoculture of the invader Examples Garlic mustard Purple loosestrife 4 2/10/11 Two Main Impacts of Invasive Species Change in na<ve animal species Reduc<on in food sources Plant fruits and nuts Insects Lower niches available for coloniza<on Reduces nes<ng places small birds and water fowl Fewer trees for species such as woodpeckers Reduced resources for larger mammals Produc<on of toxic substances in invasive plants Purple loosestrife produces toxin that causes a decline in amphibian popula<ons Common reed and Japanese knotweed causes toxic effects to salamander and tree frog species The ability to outcompete and replace na<ve species is a hallmark characteris<c of invasive species. There are other large ­scale environmental impacts at the na<onal or global level, such as climate change that can be brought about by invasive plant species but this is beyond the scope of this course. 5 2/10/11 6 2/10/11 The Coopera?ve Agricultural Pest Survey (CAPS)Plants hNp://extension.entm.purdue.edu/CAPS/plants.html The Coopera?ve Agricultural Pest Survey (CAPS) hNp://extension.entm.purdue.edu/CAPS/browsePest.html The Midwest Invasive Plant Network hNp://www.mipn.org Purdue Weed Science Page invasive Plants hNp://www.ag.purdue.edu/btny/weedscience/Pages/InvasivePlants.aspx 7 2/10/11 Invasive Plant Fact Sheets • Asian bush honeysuckle • Autumn Olive • Crown vetch • Hydrilla • Japanese knotweed • Japanese honeysuckle • Oriental biTersweet • Privet, blunt leaved • Water hyacinth 8 2/10/11 9 2/10/11 10 2/10/11 11 2/10/11 12 2/10/11 13 2/10/11 14 2/10/11 15 2/10/11 16 2/10/11 17 ...
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