Once you have completed a climate change experiment in the BCCVL, the results page shows you a variety of different outputs. The BCCVL offers three ways to visualise the outputs including displayed individually (Results tab), displayed side by side (Compare Maps tab) and overlaid on a single map (Overlay Maps tab). Below is an explanation on how to interpret the outputs of a climate change experiment.
Future projection map
One of the primary outputs of a climate change experiment is a map that shows the predicted probability of presence under future climate conditions. It is important to note that this map shows the distribution of suitable habitat as defined by the environmental variables that you included in the species distribution model and the selected future climate scenario, not a prediction of exactly where the species occurs. The prediction is visualised as the suitability of a grid cell on a scale from 0 to 1, where 0 refers to very low suitability and 1 refers to very high suitability.
Change in probability map
The next output is a map which shows the difference in the predicted probability between species distribution model (SDM) probability and the climate change model (CC) probability. This prediction is visualised as the probability of occurrence for any location between current and future projections. The map shows a grid cell on a scale from -1 to 1, where -1 refers to a low predicted probability and 1 refers to a high probability.
Change in species range map
The Change in species range map is generated based on binary model outputs from the species distribution model (SDM) and climate change (CC) experiments. The predicted probability maps from the SDM and CC are transformed from a continuous probability map (with values ranging from 0 to 1) to a binary map (presence/absence) using the threshold selected on the Source Experiment tab when designing the CC experiment.
The resulting change in species range map indicates for each grid cell whether:
Blue: the species is present in both SDM and CC predictions, thus no change.
Orange: the species is present in SDM prediction, but absent in CC prediction, thus decrease in range.
Green: the species is absent in SDM prediction, but present in CC prediction, thus increase in range.
White (no colour): the species is absent in both SDM and CC predictions, thus no change.
Change in species range table
The change in species range table shows the number and percentage of grid cells for each of the categories in the species range change map + area km2 calculated based on actual size of grid cell. This table also shows the range change in km2 for example this table shows the suitable habitat will contract 27432.611 km2 under the future climate scenario but will expand 368386.172 km.
Change in centre of species range table
The change in centre of species range table shows the minimum, maximum and central values of latitude and longitude of current and future predicted distribution and the change between those locations in meters.
Centre of range is calculated using the COGravity function in the SDMTools R package, https://www.rdocumentation.org/packages/SDMTools/versions/1.1-221/topics/COGravity