Forest Eco Exam 2

invasive species

established populations in a new area, persist + affect ecosystem functioning

-plants, pathogens, animals, aquatic species

Exotic species

introduce, non-indigenous species, alien species

How do exotic species arrive in new areas?

-purposeful introduction (agriculture, horticulture)

-shipping methods/materials (packing materials, ballast water)

-hitching a ride (other plants/animals, tourists)

1% rule

only about 10% of arrive species establish, but only 1% in total become invasive

What factors allow invasive species to suceed?

-release from natural predators and enemies

-fill unoccupied ecological niche

-superior competitive ability

-have not coevolved

Role of disturbance in plant invasions

-disrupts ecosystem, community or population structure changing resource availability or the physical environment

-some form of disturbance usually accompanies the success

-many invasive plat species are also pioneer species

• fast growth, young reproduction, large seed dispersal’s- often by wind

Cost of invasive species

-costly control efforts are often unsuccessful

-more cost effective to prevent/minimize their entry

Phases of invasion

1. Lag Phase (prevention is possible)

2. Colonization Phase (containment is possible)

3. Naturalization (becomes a restoration project? or nothing can be done/left as is?, theoretical?)

Damage and alteration of plant community composition

-Direct destruction (emerald ash borer, chestnut blight)

-Outcompete natives for their niche (buckthorn, purple loostrife)

-Alter niche or create new niches (earthworms, cheatgrass)

• “Ecosystem engineer”

Potential Changes in ecosystem functioning

-Hydrology

-Nutrient Cycling

-Fire Regimes

-Carbon Storage

-Biodiversity and Wildlife

Control of invasive species

-Prevent entry

-Biological Control (weevils and such)

-Direct Measures (pesticides, herbicides, weeding)

CWD- larger dead woody material

-Coarse: woody debris accumulation

-Can include both DDW and snags

-DDW biomass (carbon sequestration)

-snag volume and biomass

Why is CWD important?

densities vary by decay class, CWD type, and species

CWD interactions importance

-wildlife

-plants

-insects

-ddiversity

-stream ecology

-soil and nutrient cycling

Creating CWD through management or lack thereof

-killing standing trees for snags

• must be big enough

• wont be full of necessary bugs

-species and size matters

-no tip up mounds will be created if you cut it

-functionality

• decay stages, hollow? size?

-its not known how much there should be for proper ecosystem function