PLANT SUCCESSION AND ITS EFFECTS ON WILDLIFE
“Nature doesn’t stand still.”
1. Bare Ground 2. Annual forbs and grasses 3. Perennial forbs and grasses 4. Shrubs 5. Young woodland or trees 6. Mature woodland or trees
Takes time Weeks Months Years to Decades Centuries Constant
Climax Stage (wetter regions) (dryer regions)
Shortgrass Prairie rolling hills plains valleys streams
Pond or wetland succession
Natural Disturbances Fire Tornado, floods, natural disasters Ice storms Insect/Disease outbreak Lightning Grazing Controlled burns Plowing/ chopping/ herbicide timber harvest water control Man-Induced
Different wildlife species are associated with different stages of succession Stages 5 and 6 Stages 3 and 4
Illustration by Dale Crawford Copyright Wildlife Management Institute 1999
Illustration by Dale Crawford Copyright Wildlife Management Institute 1999
Vertical Structure (Layering)
1. Bare Ground 2. Annual forbs and grasses 3. Perennial forbs and grasses 4. Shrubs 5. Young woodland or trees 6. Mature woodland or trees Recall stages of succession
Stage 6 Mature woodland or trees Canopy Layer Shrub Layer Herbaceous Layer 3 General Layers:
OR Stage 6 Mature woodland or trees Canopy Layer only
Vertical arrangement is KEY for wildlife
Wild Turkey
Interspersion (Horizontal Arrangement)
Refers to arrangement of areas in different successional stages relative to one another (including the layers, or vertical structuring, WITHIN each successional stage) Interspersion
Many wildlife species require MORE THAN ONE successional stage to supply all requirements or “ingredients” (food, water, cover and space). If this is the case, then “Valuable” Interspersion would be? 1. Several stages near one another, OR 2. Linked together by a “corridor” of habitat (mainly cover) to allow for safe travel Goal Here: HIGH interspersion
But, some wildlife species obtain all their requirements from ONE successional stage, if required “ingredients” are present in that stage. (Note: how would this be possible?) If this is the case, then “Valuable” Interspersion would be? 1. Large area in that successional stage with little variation around it. Goal Here: LOW interspersion
Usually, however, more interspersion supports a greater variety of wildlife. High or Low Interspersion? HIGHLOW
Quick Tip: Learn the Interspersion Index! horizontal + vertical = = 0
Edges and Contrast
EDGE Boundaries where two different successional stages meet. 1. High contrast edge - very narrow and abrupt (stage 6 meets stage 2) 2. Low contrast edge- usually wide, gradual and contains aspects of both successional stages (stage 3 meets stage 4)
LOW High or Low Contrast Edge? HIGH