engleski

What can we learn about ecology of invasive plants from unsystematically collected data?

Chorological data can differ by various criteria (origin, age, format etc.) Here, we are interested in various spatial accuracy of chorological data on ivasive plants in Croatia, and how this difference affects environmental data which can be attributed to recorded localities. Chorological data in Flora Croatica Database originates from various sources (literature, herbarium, field data) and are associated with one of the 11 levels of spatial precision. Latter are ranging from least accurate that corresponds to whole region (e.g. Dalmatia)to the most accurate levelcorresponding to coordinates obtained by GPS devices. More than 11000 chorological data were joined with environmental data (topography: elevation, slope, aspect ; climate: yearly precipitation, mean and minimum temperature, distance from settlements, human population density)within the frame of Geographical Information Systems. Descriptive statistics for environmental data were calculated for different subsets that were separated based on their spatial accuracy (e.g. all data, highest precision data, upper half precision data, least precise data etc.). This was done for individual plant invasive species and for set containing data on all species. Results have shown that data with less spatial accuracy do not have substantial effect on the information about environmental conditions in which a certain invasive plant occures, when they are analysed together with data with higher spatial accuracy. However, this is not the case when we use inprecise data soley, whereas such analyses provide significantly different information than those obtained with spatially more precise data. Still, some relevant information about the ecology of species could be aquired even with less precise data, with some help of spatial analyses (creating buffer zones and employing neighbourhood statistics) prior to joining environmental data to such localities.

GIS; spatial precision; environment; invasive plants

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