Slide 22: Species distribution datasets
Species distribution data are the backbone of any modelling process, and whilst the optimal source for data is through field work, there are a number of different sources and datasets that provide suitable data, depending on the species being modelled:
Museum/Herbarium data e.g. Precis (Sabonet)
Survey Atlas data e.g. Protea Atlas
Expert Atlas e.g. Birds of Africa
Field data e.g. Ackdat or TSP databases
Presence / Absence data - it is rare to obtain comprehensive absence data for a species, because unless it is specifically being searched for within an area, many species may be easily overlooked. Ideally, though we should include absence data when constructing models, as it improves model accuracy considerably.
Georeference accuracy e.g. GPS / QDS Many older datasets will have considerably poorer reference accuracy, and consequently will be less suitable for fine-scale mapping.
Taxonomy affects numbers - as the taxonomic definitions of species change, so the number of records for a given species will differ according to the date of collection and the current taxonomical understanding.
Taxonomic updates of older museum data - for this reason it is important to periodically update the taxonomic definitions of older museum records if at all possible.