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Fire’s Effects on Wildlife. Direct Effects. Few studies, marked re-capture approach ideal Body size and mobility, i.e. burrowing, influence direct mortality Life cycle stages are impacted differently Depends on fire regime Frequency, intensity, extent, and season
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Direct Effects • Few studies, marked re-capture approach ideal • Body size and mobility, i.e. burrowing, influence direct mortality • Life cycle stages are impacted differently • Depends on fire regime • Frequency, intensity, extent, and season • Extent-small area, greater ability to repopulate • Must look at populations rather than the individual
Indirect Effects • Fire severity and resulting successional patterns dictate wildlife habitats and the effect on wildlife • Importance of fire regime • (+/-) Consumer response is species dependent
Mechanisms of post-fire population change • Population response to fire regulated by: • Availability of food resources • Changes in cover • Movement of populations in/out of burned/unburned areas (migration, immigration)
Understanding the Consumer Response to Food Resources • Fire alters production, species availability, and food quality • Migration and immigration • Short term effects • Deer mice in prairies or grasslands • Some mortality during fire may decrease populations • Adapted to postfire environment: insects, wind-dispersed seeds, soil seed bank • Populations may increase several-fold in burned areas
Understanding the Consumer Response to Food Resources • Alternatively, shift in food sources • Ex. Australian eucalypt forest • Bettongs exploit fire adapted fungus • -- Ex. Primates in Borneo shifting • food sources • Flowers and fruits unavailable • Shift to foliar/herbaceous vegetation and • caterpillars/larvae of wood boring insects
Consumer Response and Food Quality • Pulse of higher quality new growth • Increase in protein (nitrogen content) in new growth • New tender shoots with greater digestibility • Increase in population growth rates • Ex. Domestic grazers
Changes in Cover • Burned vegetation results in drastic change in both physical and thermal cover • Grasshoppers – decline after fire, require a well-developed litter layer for habitat • Earthworms – found 10-20 cm below soil surface, direct affects only with severe fires; may increase postfire due to increased plant productivity • Physical protection from predation • Structure provides protective habitat • Affects visibility
Red-cockaded woodpecker in loblolly pine forests • Forage behavior of woodpeckers: • Foraged at greater heights in areas of tall and dense midstory vegetation • Concentrate foraging activities in forest stands or openings with reduced midstory vegetation • Fire regime in Loblolly pine • Fire-maintained, frequent surface fires • Changes in fire regime: fire suppression
TTYP • Why do red-cockaded woodpeckers require fire in order for long-term survival of their populations in loblolly pine forests? • What are the specific mechanisms?
Mortality of Cavity Trees • Disturbance by prescribed burning, thinning, winds, and southern pine beetle increases cavity tree mortality.
Balancing Protective Cover and Food Availability • Tallgrass prairie example • Bird response • Increase in seed/insect availability • Decrease in cover, nesting habitat, and predator protection • Small mammal response • Some small rodents, i.e. prairie vole, are small navigate litter layer and find seed • Other larger rodents, prefer burned area with easier seed access
Structural Diversity • Interspersion of food resources and cover • Positive or negative effects depending on the severity and extent and the wildlife considered • Reduced habitat heterogeneity by large extent, severe fires
Example: Structural Diversity • Habitat diversity and complexity, each supports a specific faunal community • Ex. Snags important for birds, mammals, reptiles, amphibians, and invertebrates
Plant Succession and Animal Response: moose & caribou in boreal forests • Discuss the following questions: • How are moose/caribou affected by fire? • How would you design a management plan to manage for moose OR caribou? • How would you design a management plan to manage for moose AND caribou?
Plant Succession and Animal Response • Browsers in North American boreal forest • Caribou eat lichen, slow growth, easily burned • Caribou in late successional • Moose eat woody resprouts (birch, aspen) • Moose in early successional
Structural Diversity and Patchiness • Mature cover provides refuge for migration • Adjacent high quality growth in burned areas • Mosaics of food resources and cover create structural diversity • Ecotones - boundaries