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July 3 rd, 2014 Charlotte Germain-Aubrey cgermain@ufl.edu ECOLOGICAL NICHE MODELING: INTRODUCTION
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Why is a species where it is ?
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Mutation Dispersion Selection Competition Human activity Chance Time GEOLOGY GEOGRAPHY CLIMATE
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What is a niche ???
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Grinellian niche: habitat requirements that allow a species to persist and reproduce Eltonian niche: role that a species plays in a community, rather than habitat Hutchinsonian niche: Fundamental niche: area with optimal biotic and abiotic conditions, but free of interference from other species Realized niche: subset of the fundamental niche actually occupied by the species, due to pressures from other species.
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What is a niche ??? Grinellian niche: habitat requirements that allow a species to persist and reproduce Eltonian niche: role that a species plays in a community, rather than habitat Hutchinsonian niche: Fundamental niche: area with optimal biotic and abiotic conditions, but free of interference from other species Realized niche: subset of the fundamental niche actually occupied by the species, due to pressures from other species. Optimum environment for growth, reproduction, and survival of a species Defined by: Substrate Microclimate Competition
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Soberon and Peterson (2005) Biodiversity Informatics 2:1-10 Appropriate set of abiotic factors – fundamental niche Right combination of species interactions – realized niche Regions accessible ecologically
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Soberon and Peterson (2005) Biodiversity Informatics 2:1-10 Appropriate set of abiotic factors – fundamental niche Right combination of species interactions – realized niche Regions accessible ecologically Occupied niche
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Holt, R. D. (2009) PNAS 106 : 19659-19665 The occupied niche can change and shift over time, within the realized niche. Fundamental niche is still worth estimating, even if it is not a perfect representation of a species distribution at a precise point in time.
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How do you establish a species’ environmental tolerance ? Ex situ: Common garden experiment on site (controlled field conditions) Common garden experiment in situ (where the tested climate occurs) Thorough field surveys over time (usually leads to distribution map = absence map) VERY DIFFICULT !!!
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ECOLOGICAL NICHE MODELS Look at a set of conditions under which a species occurs naturally (presence data) When possible, also look at conditions under which the species does NOT occur (absence data) BUILD THE MODEL
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ECOLOGICAL NICHE MODELS Look at a set of conditions under which a species occurs naturally (presence data) When possible, also look at conditions under which the species does NOT occur (absence data) BUILD THE MODEL Occurrence data: where the species is present, but not where it is absent Distribution map: where the species is absent, but not where it is present
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ECOLOGICAL NICHE MODELS Look at a set of conditions under which a species occurs naturally (presence data) When possible, also look at conditions under which the species does NOT occur (absence data) BUILD THE MODEL Apply the model in space (around where it occurs naturally, or in another area), or in time (where did it use to occur, or where will it occur in the future) PROJECT THE MODEL Occurrence data: where the species is present, but not where it is absent Distribution map: where the species is absent, but not where it is present
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NICHE MODEL APPLICATIONS PRACTICAL Invasive species Disease Data deficient species Conservation/Land Management THEORETICAL Diversity through time Evolutionary patterns
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Causes of speciation G RAHAM, C. H., S. R. R ON, J. C. S ANTOS, C. J. S CHNEIDER, and C. M ORITZ. 2004. Integrating Phylogenetics and Environmental Niche Models to Explore Speciation Mechanisms in Dendrobatid Frogs. Evolution 58: 1781.
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Past distributions/refugia and phylogeography hypotheses
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K.C. Ruegg, R.J. Hijmans, C. Moritz (2006) Climate change and the origin of migratory pathways in the Swainson’s thrush, Catharus ustulatus. Journal of Biogeography, 33 (2006), pp. 1172–1182
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FLORIDA PLANT MODELING PROJECT Bioclim correlation 8 layers < 0.85 Altitude Geology
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Wunderlin list of 4,094 species of Florida plants 3 EPA ecoregions 391,937 343,266 dated 30+ points per species 372,241 pts for 1,738 species
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Florida plant diversity heat map
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Endemism hotspots # endemics / total # species
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Between now and 2050… # spp 2050 - #spp now Panhandle species moving NORTH ! Peninsula species moving SOUTH ! 60 speccies go extinct
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The spread of the endemics
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