Landscape Ecology Large-scale Spatial Patterns and Ecological ProcessesObjectivesLandscape ecology - focus on larger scale with much habitat heterogeneity.Landscape ecology: Study of relationship between spatial pattern and ecological processes over a range of scales. Includes human influencesA mosaic of habitat types - both terrerestrial and aquatic - of varying shapes and sizes.Landscape mosaics reflect natural and human influences - from the past….…and from the presentAnimals can alter landscape mosaic …an ecosystem engineer!Humans as most impressive ecosystem engineers…create a mosaic of habitat types.Landscape info gathered from satellite (here using reflected wavelengths in visible spectrum).…or from wavelengths in visible + near-infrared spectrum (vegetation = bright red)Remote sensing used to quantify landscape features.Y axis = how well amount of wetland habitat at different distances from local wetland affects species presence locally? Which distance explains best for species a? species c? What is the ‘take-home message’?Components of landscape structure:Landscape structure… influences ecological processes:Fragmentation: creation of habitat patchesWhat are effects of fragmentation on landscape pattern?How does habitat area affect species richness?How does fragmentation affect prevalence of Lyme disease?Many aspects of ecology are affected by: habitat fragmentation + ‘edge effects’ = ?What happens to amount of edge habitat with habitat fragmentation? What happens to ‘edge specialists’? Interior specialists?Fragmentation, edge effect, and cowbird parasitismHow does cowbird parasitism change from the edge into the interior of the forest? Are cowbirds edge- or interior-specialists?Question: Does fragmentation affect forest ‘quality’?Minimum Critical Fragment Size StudySlide 26Slide 27How does fragment shape affect edge/interior habitat? Which has most edge (same area)?PatchHabitat fragmentation --> suitable habitat patches separated by unfavorable habitatHabitat patchiness has led to 3 models of populations:Metapopulation = population divided by habitat heterogeneity into subpopulations with varying amounts of migration between patches.***What determines if a matrix is a barrier to movement?***What factors would be incorporated in a model of metapopulation dynamics of mountain sheep?Factors that metapopulation dynamics depend upon:What features help to diminish the effects of fragmentation on movement?Experimental patches used to study effects of habitat corridorsWhat is the main conclusion of the effect of corridors on movement?Slide 39How do corridors affect gene flow? Inbreeding? genetic cohesion of metapop?Why did these genetic differences between populations in small, isolated patches arise?How to study whether organisms respond to landscapes at different scales. Elements of scale: Grain = resolution Size = extentDo different types of bees respond differently to landscape scale of semi-natural habitats?Landscape EcologyLarge-scale Spatial Patterns and Ecological ProcessesObjectivesSpatial aspects due to habitat heterogeneity• Structure• Matrix• Mosaic• Fragmentation creates patches• Influences on ecosystem processesSpatial dynamics• Metapopulations • Structure• DynamicsSmall populations in patches • Risk of extinction• Rescue effectLandscape ecology - focus on larger scale with much habitat heterogeneity.Landscape ecology:Study of relationship between spatial pattern and ecological processes over a range of scales.Includes human influencesA mosaic of habitat types - both terrerestrial and aquatic - of varying shapes and sizes.Landscape mosaics reflect natural andhuman influences -from the past….…and from the presentAnimals can alter landscape mosaic …an ecosystemengineer!Humans as most impressive ecosystem engineers…create a mosaic of habitat types.Landscape info gathered from satellite (here using reflected wavelengths in visible spectrum).…or from wavelengths in visible + near-infrared spectrum (vegetation = bright red)Remote sensing used to quantifylandscape features.Y axis = how well amount of wetland habitat at different distances from local wetland affects species presence locally? Which distance explains best for species a? species c? What is the ‘take-home message’?Components of landscape structure:•Size (area)•Shape•Number•Position and pattern ….of patches (or landscape elements) in a landscapeLandscape structure… influences ecological processes:•Flow of energy•Flow of materials•Movement of species ….across a landscape•Small population dynamics/genetics•Species interactions/community dynamicsFragmentation: creation of habitat patchesWhat are effects of fragmentation on landscape pattern?• Total amount of habitat….• Number of habitat patches…• Amount of edge habitat…• Average patch size…• Patch isolation…How does habitat area affect species richness?Figure 2How does fragmentation affect prevalence ofLyme disease? Figure 3Many aspects of ecology are affected by:habitat fragmentation + ‘edge effects’ = ?What happens to amount of edge habitat with habitat fragmentation? What happens to ‘edge specialists’? Interior specialists?Fragmentation, edge effect, and cowbird parasitismHow does cowbird parasitism change from the edge into the interior of the forest?Are cowbirds edge- or interior-specialists?Figure 4Question: Does fragmentation affect forest ‘quality’?• Hypothesis: Fragmentation reduces forest quality (e.g. tree growth and survival).• Prediction: Species diversity and biomass will be lower in forest fragments compared to forest interior, especially along edges.Minimum Critical Fragment Size StudyWhat is the question being addressed?Describe the results.What data are missing before a conclusion is reached? Figure 5How does fragment shape affect edge/interior habitat? Which has most edge (same area)?Figure 6Patch•Relatively homogeneous area that differs from its surroundingsMosaic: pattern of patches•Formed by patches within landscapeMatrix•Background in which mosaic imbedded; most continuous element within landscapeHabitat fragmentation --> suitable habitat patches separated by unfavorable habitat Figure 7Habitat patchiness has led to 3 models of populations:Metapopulation = population divided by habitat heterogeneity into subpopulations with varying amounts
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