By using machine learning, which allows searching for new information in data sets, we investigated the interactions between stressors and their impact on biological processes in river sediments overgrown by biofilm. Modelling using decision trees enabled identification of not yet demonstrated interactions between stressors and measured environmental factors and determination of the threshold values. In this way, new knowledge about complex interactions between water temperature, catchment land-use, and physico-chemical properties of water, that affect quantity and activity of biofilm in river sediments, have been provided. We have shown that relations between stressors and environmental factors and their biological response depend primarily on the temperature range at which they are observed. The achievement is part of a wider research topic, where the program group seeks to gain a deep understanding of the influence of interconnected ecological factors and environmental stressors in river ecosystems, especially within transition zone between surface and groundwater, in shallow hyporeic zone (e.g., within riverbed sediments). The ecosystem processes taking place in these areas are crucial for the quality of surface as well as groundwater and represent important ecosystem services for inland waters. The rest of this research findings were in the reporting period published in journals Fundamental and Applied Limnology (COBISS-ID 4483407), Hydrological Processes (COBISS-ID 4307023) and Journal of Soils and Sediments (COBISS-ID 4134223).
COBISS.SI-ID: 4885071
We examined intra- and interspecific variation in functional morphology and whole-organism performance in a sympatric lizard species pair in the area with a high potential for competition. The biggest variation between species was found in two functional traits, bite force and climbing speed, linked with corresponding morphological traits. The species with larger and taller heads exhibited correspondingly stronger bite forces. Both traits may potentially promote segregation between species in trophic niche (stronger bites relate to harder prey) and in refuge use (flatter heads allow using narrower crevices, hence, influencing escaping from common predators). Stronger bites and larger heads also provide one species with a dominant position in interspecific agonistic interactions. Our results exemplify how the joint examination of morphological and functional traits of ecologically similar and sympatric species can provide a mechanistic background for understanding their coexistence, namely syntopic populations that are frequent in the study area. The identified roles of functional morphology in this system of sympatric rock lizards support the contribution of functional diversification for the complexity of community structure via coexistence. The later is the major significance of our work that directs further studies in the field of ecology to integrate functionality of species traits with ecological processes, such as species coexistence patterns. The article was featured on the Functional Ecology journal's blog and the leading author was nominated for the British Ecological Society's Haldane Prize, given for the best paper by an early career researcher in Functional Ecology in 2018.
COBISS.SI-ID: 4728998
The paper features the second stage in developing an environment-friendly control method of the invasive brown marmorated stink bug (BMSB), based on vibrational playback. In an earlier publication (Polajnar et al. 2016, Physiological Entomology), we described natural sexual behaviour of this species, along with the discovery that males react to one female signal type by actively searching for the source. We then designed a series of playback experiments with different setups - vibrating a hole in a cage, a point on a flat surface, a point on a host plant etc., either males alone or in groups with females - and demonstrated that approximately half of the males can be attracted to a vibrating device. A commercial company from Italy is now developing a field trap for BMSB on this basis, which is predicted to prove more efficient than pheromone traps. Description of the work was published in the Journal of Pest Science, one of the most reputable journals in the field of pest control and the second highest cited journal in the field of entomology.
COBISS.SI-ID: 4315727
The mechanism of orientation of insects towards the source of vibrational signals remains one of the key open questions for understanding how small animals can extract information from faint substrate vibrations. Combining different experimental approaches in the model species, southern green stink bug - analysing which parameter reflects signal direction, behavioural and neurobiological experiments - we discovered that stink bugs are capable of detecting less than 0.5 ms delay between excitation of ipsi- and contralateral legs and use this parameter for an accurate directional decision on a stem-leaf crossing, while amplitude often points to a part of the crossing away from the source of vibrations. These findings enable searching for analogies with human hearing and understanding the evolution of sensory systems which have to function within physical constraints. They may also be useful in designing systems for orientation in miniature robotics. The paper was published in the journal Scientific Reports by the Nature Publishing Group.
COBISS.SI-ID: 33712601
In our work, we studied two properties of metabolism in three different groups of terrestrial ectothrms (from groups of reptiles, amphibians and beetles), respiration and metabolic potential, to investigate whether these two properties depend on the environment in which they live or have the potential of local adaptation or acclimatization to local conditions. We found that respiration is relatively similar among the groups compared in sympatry, while for all three groups the average biochemical ability of metabolism is higher in a species that is a highelevation specialist. These results, which show a consistent pattern in three independently developed animal groups, indicate an allencompassing metabolic syndrome. They represent a new understanding of the ability of adaptations in metabolism, which is still extremely poorly studied trait in ectothermic organisms. Results are of paramount importance, as they indicate that metabolism is a property that is varying in relation to species distributions and is thus providing a mechanistic link between physiology and spatial distribution of species. We have also demonstrated that the metabolic potential is a good descriptive property that has an adaptive potential and is therefore useful for the research of metabolic responses to environmental factors. The article's photo of a model species, Salamandra salamandra, was featured as the cover photo of the journal's issue of Ecography. The article was also featured in Ecography journal's blog and Facebook page.
COBISS.SI-ID: 4584015