GBIF Niche Modeling

Go to: http://www.gbif.org/

Ignore the “under construction” notice. On the left hand menu bar, choose “search.”

Choose “Explore species.” Do not use the search option.

Select “Kingdom: Plantae”

Use search to locate species of interest. (Sporobolus stapfianus, Eragrostis curvula, Eragrostis tef)

Go to overview page. Note the taxonomic ranking listed across the top of the page. Occurrence overview is available by scrolling down the page. Note that only a few occurrences will be mapped, even if there are many records. This is because only records with lat/long data can be mapped. Researchers often invest a great deal of time to generate lat/long coordinates for occurrences, although the use of GIS in the field will reduce this problem in the future. Another problem is anomalous occurrences. These are occurrences that are unlikely, and when records are checked they are often either data entry mistakes (ie an occurrence in the ocean because lat/long was incorrectly entered) or non-native sites (ie a botanical garden or zoo). Large data sets are a boon to researchers, but data are rarely in a ready to use form. Data curation is an important part of research with large data sets. The Explore and List sections include more information on occurrence data.

Go to Explore: Occurences. On this page users have more access to the data. Data can be downloaded (Download: Spreadsheet of results) or restrict the data sets by country or by dataset (Specify). Restricting data by country or specific data set can cut down on anomalous occurrences.

A niche model is an estimate of where an organism could potentially exist. Niche models are based on occurrence data, and layers the user selects. The layers include information about temperature, precipitation, altitude, etc. The more layers used to generate a niche, the more accurate the niche is likely to be, but the longer it takes to compute. Also, since likely niche conditions are identified based on occurrence data, the niche models for species with more occurrences tend to be more accurate since there is more detail about niche conditions. Niche models can be used to identify field locations in which to search for organisms, to study dispersal patterns, and for conservation planning. Niche models are an important tool in biogeography, however niche models are limited. There are a number of different niche modeling programs, and each has its strengths and weaknesses. Its very important to remember that species distributions are affected by more than the climactic parameters in niche models such as precipitation and temperature. Factors influencing species distribution include parasites and disease, food availability, predators, physical barriers, and competition. Niche modeling is just one piece of the puzzle.

Select “Create: Niche Model.” Scroll down to find the layers. Select or deselect as many as you wish. It’s interesting to compare different niche models using different parameters, so play with the layers to determine which are most important in this model.

Select “Create Model.” This usually takes less than the predicted 5 minutes – be patient. One way to work with the different models is to take a screen shot of each for class discussion. Be sure to note the layers for each niche, as well as the species, and any data set restrictions you used to generate the niche.