ECOLOGICAL IMPACTS OF INVASIVE SPECIES. on Native Species and Ecosystems

Transcription

1 ECOLOGICAL IMPACTS OF INVASIVE SPECIES I. Competition on Native Species and Ecosystems II. Consumption (invasive species eat native species) III. Other deadly impacts on individuals and populations IV. Harm to Ecosystem Functions (alterations in how things used to work together)

2 invasive shrub Winged Euonymus ( Burning Bush ) What is this plant competing for? bhld.wordpress.com COMPETITION

3 COMPETITION: What would happen to a rare plant? Japanese Hops Invasive Vine grows over ground and up trees

4 COMPETITION via INTERFERENCE Why is nothing growing around this Spotted Knapweed? allelopathy

5 CONSUMPTION Predation animal consumption Feral house cats kill native birds and small mammals enough to reduce populations Herbivory plant consumption

6 REVIEW: Short Definition of Invasive = (1) and (2). In Britain, non native Eastern Gray Squirrel (from North America) outcompetes native red squirrel for acorns. Also was the source of Squirrel Pox.

7 DEADLY EFFECTS OF WOOD BORING INSECTS ALB EAB Disrupt sap flow but trees can undergo a lot of internal structural damage first.

8 OTHER EFFECTS HYBRIDIZATION invasive Eurasian Water milfoil (Myriophyllum spicatum EWM) crosses with native Northern Water milfoil (M. sibiricum NWM) Hybrid Eurasian Water milfoil grows more vigorously than either parent Also, Hybrid is resistant to 2,4 D which is a herbicide used to control EWM If there is a lake with EWM, NWM and the hybrid, what might happen over time to the population of the native NWM? And what might happen to manager s ability to control unwanted watermilfoil with 2,4 D?

9 HARM TO ECOSYSTEM FUNCTIONING 1 species replaces many WHAT HAPPENS THEN? Japanese Knotweed Phragmites aka Common Reed

10 BIOLOGICAL DIVERSITY Species Richness is one measure of biological diversity. Richness = the number of different species present Many bird species will nest in Phragmites, but the more rare species don t. Imagine a site that gets invaded by Phragmites and one rare species is lost, and one new common species comes in. Then, if we use species richness to measure biodiversity, has bio diversity at this site changed?

11 What if there were 20 sites across the landscape that got invaded by Phragmites and at each one a different rare species was replaced by a common species. Then taking the landscape as a whole, would there be a change in bio diversity? M

12 HARM TO ECOSYSTEM FUNCTIONING Crazy Snake Worms 1 2 worm castings soil change in nutrient cycling invasive plant Crazy Snake Worm population increasing 3 4 changed habitat Happy Garlic Mustard? Happy Salamanders? native

13 HARM TO ECOSYSTEM FUNCTION NUTRIA not in CT but if it were a bit warmer here... COMPETITION FOR FOOD Invasive Nutria consume marsh plant roots HABITAT DEGRADATION Bank caves in erosion sediments in water 2 3 litters/yr w/ up to 13 young each HABITAT LOSS AND DEGRADATAION Nutria fragment continuity of marsh vegetation by denuding vegetation and by creating swimming channels

14 HARM TO ECOSYSTEM FUNCTIONING Invasive Purple Loosestrife Hungry tadpoles Native Decomposers not used to it. Nutrient cycling in water altered fewer adult woodfrogs fewer baby owls survive

15 Ecological Impacts of invasive species can be complicated

16 And you might not see that a problem has been building up until there is a change that you just can t overlook.

17 JAPANESE BARBERRY Berberis thunbergii red fruits early spring scene Why is Barberry so successful in our forests?

18 JAPANESE BARBERRY Berberis thunbergii red fruits Lyme Disease spirochete is native Deer tick is native Complications...

19 the end

20 Garlic Mustard

21 herbivory bugs ALB, EAB, HWA, SPB, Gypsy Moth, Deer, Pig rooting HWA/ ALB disrupts sa to needles/ is Bambi invasiv

22 Bambi s mother causes harm to native plants. Is she an invasive species?

23 Predation native sawfly larva eating Black Cherry part of good cycle

24 harm to habitat change in plant species is important because plants form the basis of most animal habitats what do animals need food, shelter, water, space, others of their kind, n fix, ;

25 ECOLOGICAL IMPACTS on plants, animals, and ecosystems competition resource competition (Eastern Grey Squirrel outcompetes European Red S. invasive plants can overwhelm rare native species and cause them to die for lack of light after they are dead, they may not come back. Extirpation vs Extinction. interference knotweed allelopathy consumption of native by invasive species herbivory predation wood boring insect larvae consume wood ultimately disrupting flow of xylem and phloeum check this Other harm to individuals and/or populations disease deadly effects of wood boring insects loss of local populations (or even entire species) through hybridization Harm to ecosystem functions (alterations in how things work) direct loss of ability to provide habitat usually loss of habitat plant, but rock snot is harm to stream bottom substrate where insect larvae live don t provide food in leaves; or timing long run loss of diversity number of species and difference between common species vs rare indirect/complicated changes PL + wood frogs loss of food source for native plant decomposing organism ultimately affects fish that eat wood frog tadpoles and raccoons and owls that eat adults bio control gone wrong