Project name: Establishment of the National Monitoring System for Invasive Alien Species (KK.06.5.1.01.0001). „Analysis of existing data on alien species and IAS with an elaboration of mapping methodology, service of mapping of alien species and IAS with development, testing and completing of the IAS monitoring program and service of analysis of pathways of introduction and spread of IAS“ – Group 15: “Mapping of alien and invasive alien species of mammals related to freshwater ecosystems and development, completing and testing of the monitoring program”
Client: Ministry of Economy and Sustainable Development
Period: 05/2019 – 02/2021
This project included mapping of alien and invasive alien mammal species related to freshwater ecosystems (coypu – Myocastor coypus, muskrat – Ondatra zibethicus and American mink – Neovison vison) in priority areas in the Republic of Croatia, as well as development, testing and finishing of monitoring programs for two of those species – the coypu and the muskrat.
The mapping was carried out in three phases. The first one included mapping through polls/questionnaires on 85 quadrants of 10 × 10 km. The quadrats were determined based on the analysis of existing data on findings of alien and invasive alien mammal species related to freshwater ecosystems, species ecology and thepresence of suitable habitats. The second phase included mapping using the method of a visual census in 40 quadrants selected based on the results from the previous phase. The third phase included mapping using the photo-trapp method in 20 quadrants selected based on the visual census method results.
The final distribution of coypu and muskrat in the area of the Republic of Croatia was determined by modeling the distribution of these two species using the geographic information system – GIS. By applying statistical methods and processing in the program language R, the initial population size of coypu and muskrat was estimated. For each species separately the differences in relative population density were compared for different types of water bodies and for different river basins in the Republic of Croatia. Based on the above calculations, data for the coypu population trend and muskrat population trend monitoring were provided. In addition to general data for coypu and muskrat (scientific name, description of the biology of the species, description of the habitat, distribution of the species, pathways of introduction and spread of IAS, impact on native species and ecosystems), final monitoring programs contain detailed descriptions of monitoring methodology, including a description of field methods (method of selection and description of locations, duration of the monitoring), sampling design, data recording forms and method of data evaluation to continue monitoring of population trends, assessment of changes in population size and assessment of future prospects.