ECOLOGICAL NICHE MODELING: PRACTICAL July 3 rd , 2014 Charlotte Germain-Aubrey cgermain@ufl.edu ECOLOGICAL NICHE MODELS 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 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 Step 1: gather points • Occurrence points • Specimens from museum • Observation points • Distribution map (absence map) http://scienceasaverb.wordpress.com/2010/10/29/introduction-to-ecological-niche-modeling-environmental-niche-modelingspecies-distribution-modeling-part-two-what-is-niche-modeling/ Step 2: gather environmental data • • • • • Climatic Geological Soil Water Chemicals • Species interaction • positive: obligate host • negative: excluding competitor http://scienceasaverb.wordpress.com/2010/10/29/introduction-to-ecological-niche-modeling-environmental-niche-modelingspecies-distribution-modeling-part-two-what-is-niche-modeling/ Step 3: Extract environmental values at points of occurrence http://scienceasaverb.wordpress.com/2010/10/29/introduction-to-ecological-niche-modeling-environmental-niche-modelingspecies-distribution-modeling-part-two-what-is-niche-modeling/ Step 4: Build a model Here, a very simple model: 95% of the species distribution for each environmental variable http://scienceasaverb.wordpress.com/2010/10/29/introduction-to-ecological-niche-modeling-environmental-niche-modelingspecies-distribution-modeling-part-two-what-is-niche-modeling/ Step 4: Build a model Here, a machine learning model comparing the presence and absence MaxEnt http://scienceasaverb.wordpress.com/2010/10/29/introduction-to-ecological-niche-modeling-environmental-niche-modelingspecies-distribution-modeling-part-two-what-is-niche-modeling/ Step 5: project the model Here projection in the space and time of occurrence http://scienceasaverb.wordpress.com/2010/10/29/introduction-to-ecological-niche-modeling-environmental-niche-modelingspecies-distribution-modeling-part-two-what-is-niche-modeling/ Step 5: project the model Here, a projection into a new area http://www.oceanecology.ca/species_model_data.jpg ITIS National biological data Online conservation tools ITIS Environmental data Species occurrence databases Point occurrences, Valid taxonomies Range maps, Validation services Biodiversity encyclopedias Range maps Species data MAXENT Maximum Entropy algorithm used (machine-learning) to build and project niche models. 25% of dataset set aside for testing the model and giving feedback on how well it performs (machine learning process) species,longitude,latitude bradypus_variegatus,-65.4,-10.3833 bradypus_variegatus,-65.3833,-10.3833 bradypus_variegatus,-65.1333,-16.8 WHAT IS YOUR QUESTION ? WHERE IS YOUR DATA ?