Biomathematics & Statistics Scotland
Biogeography is the science of explaining the spatial distribution of living beings and of analysing the factors which may determine it. We deal with zoogeography when the investigation is related to the distributions of animals or phytogeography in the case of plants.
The spatial distribution of species is studied by atlas surveys, in which an area is divided into sub-areas called sites, usually making up a grid of squares of equal size. In any site the presence or the absence of one or more species is recorded, along with environmental and climatic variables.
Commonly the data is a map of black and white squares, where black means that at least a member of the species has been observed, whereas white means no observation of the species. Given that false observations can occur, increasing the number of black squares, and that white squares means both that the species is not present and that it has not been observed, the observation map can present uncertainty on the presence and absence of the species.
The reconstruction of the true map can be handled as the restoration of a degraded pixel image, in which some black and white pixels assume the wrong colour. In the restoration of binary images it is often assumed that the adjacent pixels in the original image are likely to assume the same colour. This assumption is also reasonable in the restoration of the observation map to obtain the true map.
In addition to the estimation of the presence and absence of a species, we are above all interested in evaluating the probability of discovering the presence of a species in a site and select the variables which can affect this probability, in order to be able to explain the heterogeneity in the spatial distribution of a species. Hence we can also have information on the suitability of sites.
Finally, we are interested in the prediction of species distribution over time, by assuming changing scenarios in the environment and in the climate.
The aims of this project will include:
The project will be jointly supervised by Luigi Spezia (BioSS), Alessandro Gimona (Macaulay Land Use Research Institute), and a University supervisor.
Applicants should have good mathematical and statistical knowledge and be interested in the statistical modelling of ecological and environmental stochastic systems.
For further details, contact Luigi Spezia
