Iulia V. Miu

Empirical analysis and modelling of Argos Doppler location errors in Romania

Advancements in tracking technology allow researchers to understand the spatial ecology of many terrestrial and aquatic species. Argos Doppler is a widely used technology for wildlife telemetry as it suits smaller species and have longer life span than miniaturized GPS. In practice, large Argos location errors often occur due to communication conditions such as transmitters settings, local environment, area of reception, behaviour of tracked individual, etc. Considering the specificity of errors and the lack of benchmark studies in Eastern Europe, our research objectives are (1) to provide empirical evidences of the accuracy of Argos Doppler locations in Romania, (2) investigate the effectiveness of straight forward destructive filters for improving Argos data quality, and (3) to provide guidance for handling Argos wildlife monitoring data to researchers in Eastern Europe. We assessed the errors associated to Argos locations in 4 geographic locations from Romania in static, low speed and high-speed tests and then we evaluated the effectiveness of Douglas Argos distance angle filter algorithm to minimize location errors. Argos locations received in our tests had larger horizontal errors than those indicated by the operator of the Argos system, including when reception conditions are ideal. The errors are highly variable within each location class, however, positions from location class 0 were constantly prone to large errors. The errors were anisotropic, predominantly oriented East and West, a pattern confirmed by the larger longitudinal errors in the vast majority of data. Errors were mostly related to movement speed of Argos transmitter at the time of reception, but other factors such as topographic conditions and position of the device toward the sky at the time of the transmission contribute at receiving low quality data.Douglas-Argos filter successfully excluded largest errors while retained a large amount of data when the threshold was properly defined for local scale (2 km). Thus, filter selection requires previous knowledge about the movement patterns and behaviour of the species of interest, and parametrisation of the selected filter must follow a trial and error approach.

Conservation priorities for terrestrial mammals in Dobrogea Region, Romania

Abstract Based on species occurrence records of museum collections, published literature, and unpublished records shared by mammalian experts, we compiled a distribution database for 59 terrestrial mammals populating the extensively protected Dobrogea Region of Romania. The spatial patterns of mammal distribution and diversity was evaluated and systematic conservation planning applied to identify priority areas for their conservation. The spatial analyses revealed that intensive sampling was not directly correlated to mammal diversity but rather to accessibility for inventory. The spatial prioritisation analysis indicated a relatively aggregated pattern of areas with a high or low conservation value with virtually no connecting corridors between them. The significant overlap between Natura 2000 sites and national protected areas induced an over-optimistic vision of the effectiveness and representativeness of existing Natura 2000 network for species found in Annexes II and IV of the Habitats Directive. These results represent a key step in identifying core areas for the protection of mammal diversity and dispersal corridors for improved connectivity, and to guide future conservation efforts in increasing the effectiveness of the existing protected areas in the context of environmental changes.