Conference Agenda

Alpine biome shifts are a model system to understand the factors driving and constraining major ecological transitions. Alpine environments (i.e., above the upper climatic treeline) are particularly exacting e.g., short growing seasons, high UV light radiation, and extreme temperature fluctuations daily and annually. Thus, evolving a trait syndrome that enables becoming alpine involves a multitude of trait complexes, integrating plant architecture (e.g., prostrate growth to leverage boundary layer effects), physiology (e.g., freezing resistance; UV protection), and reproductive traits (e.g., few-flowered inflorescences), jointly relating to these environmental challenges. In this talk, I ask the question if there is some systematic order in which ecological traits underpinning alpine biome shifts were acquired over macroevolutionary timescales. I approach this question in two ways: by analyzing the environmental niches in multiple dimensions of the high- and low-elevation plant species of the European Alps, and by focusing on phylogenetic sequences of acquisition in multiple clades of plants that diversified across mountain systems. Results suggest that trait evolution underpinning phylogenetic biome shifts constitutes a staggered acquisition of the components of complex syndromes, each component of which may exhibit rather strikingly different evolutionary patterns across clades.

Dispersal is a key process known to influence both speciation and extinction, however, the exact relationships appear to be scale- and context-dependent. Dispersal on ecological scales inhibits speciation due to increased gene flow, whereas dispersal across major barriers may increase speciation due to new opportunities for ecological specialisation and radiations. Similarly, low dispersal abilities have been linked to increased extinction rates, but in meta-populations, high levels of dispersal have also been linked to higher extinction risk due to synchronized population responses. Few studies have explicitly tested these hypotheses at macroecological and macroevolutionary scales across multiple taxa.

Using traits as a proxy for past dispersal ability in state-dependent speciation and extinction models we are linking dispersal to speciation and extinction in reptiles. Ultimately, species richness is the result of the interplay between speciation and extinction. Better understanding the links between dispersal and speciation/extinction will thus improve our knowledge of the origin of biodiversity.

What drives variation in resource use among species, trophic groups, and environments? Here, we report on a distributed experiment across Denmark, conducted mostly by children, to address this question in ants. Over two years, children conducted two-hour baiting experiments at 508 sites to investigate how ants foraged for a suite of resources. The distributed experiment, called ‘Myrejagten’ (the Ant Hunt), observed 15,329 workers from 26 species across a variety of environmental and temporal conditions, including building proportion, vegetation density, solar radiation, topographic wetness, coastal distance and Julian date. The experiment revealed that relative resource use varies among trophic levels with primary consumers showing an eight times higher preference for oil and predators a twice as high preference for protein and that environment has a significant effect on resource use. Taken together, our results highlight that engaging children can lead to discoveries at the forefront of ecology, such as the drivers of resource use at geographical scales, among species and trophic levels. Furthermore, we present some preliminary advances on an automated camera trap that can be deployed for continuous monitoring of ant resource use.

Opportunistic plant observations collected with plant ID apps such as Flora Incognita provide a rapidly growing source of spatiotemporal plant observation data. Here, we used such data to explore the question whether they can be used to detect changes in plant species phenologies. Examining 20 mostly herbaceous plant species in two consecutive years across Europe, we observed significant shifts in their flowering phenology, being more pronounced for springflowering species (6-17 days) compared to summer -flowering species(1-6 days). Moreover, we show that these data are suitable to model large-scale relationships such as "Hopkins' bioclimatic law" which quantifies the phenological delay with increasing elevation, latitude, and longitude. Here, we observe spatial shifts, ranging from -5 to 50 days per 1000m elevation, latitudinal shifts ranging from -1 to 4 days per degree northwards, and longitudinal shifts ranging from -1 to 1 day per degree eastwards, depending on the species. Our findings show that the increasing volume of purely opportunistic plant observation data already provides reliable phenological information, and therewith can be used to support global, high-resolution phenology monitoring in the face of ongoing climate change.

Ecologists have long sought universal principles that govern life's distribution on Earth. One foundational concept is the species-energy relationship, which suggests that areas with more available energy should support more species. However, linking biodiversity to energy metrics like temperature, water, and productivity often yields mixed results due to context dependence. These inconsistencies may stem from overlooking the impacts of spatial and historical processes and the influence of Earth's physical dynamics on climatic conditions, which significantly affect biodiversity patterns. Our study addresses these issues by analyzing the diversity-energy relationship within the framework of environmental space, as defined by Hutchinson's duality. Contrary to geographical analyses, in our approach, species sharing the same climate condition are grouped together even if they are not located in the same geographical area, effectively minimizing the influence of geographical processes on our analysis. Our findings reveal consistent patterns that starkly contrast with the extensive variability and context-specificity reported in previous studies. We confirm the long-standing theoretical predictions of species-energy relationships, highlighting that evaluations of these theories or hypotheses should also exclude spatial processes if they are not accounted for in the original assumptions.

To understand how species will be able to cope with changing climatic conditions, the integration of thermal physiology and biogeography bears great potential. However, it remains poorly understood whether relationships of thermal traits with the environment observed between species scale down to the intraspecific and scale up to the assemblage level with similar magnitude and direction. Here, we present results from thermal tolerance measurements in over 15,000 individuals representing 116 arthropod species along elevational gradients in Southern Asia. We quantified the associations between thermal traits and their determinants at different taxonomic aggregation levels and for two different mountain ranges.

Our findings show a consistent decrease in all thermal traits investigated with increasing elevation and an increase with the increase of temperature, especially at the assemblage level. Nevertheless, the distributional patterns of thermal traits exhibited greater variation and even contrast along the two elevational transects as well as at lower taxonomic levels. This implies that factors beyond elevation, including vegetation composition, microclimate, or landscape features, exert significant influence on the organisms’ thermal characteristics. Our study highlights this complexity of the interplay of thermal physiology and environment across different habitats and across biological scales.

We introduce mobile environmental sensing as a novel approach for mapping climate, soil, and disturbance factors across scales. Bio-indication allows to infer environmental conditions from plant occurrences based on their ecological niches. Leveraging automated plant identification apps such as Flora Incognita and citizen science millions of opportunistic plant occurrence data become available which will further increase in the future. In combination with recent advancements in pan European bio-indicator value systems this enables us to map environmental factors over large extents.

Currently, mobile sensing achieves resolutions of 0.25° across Europe and up to 100m in urban areas due to a higher citizen participation. Cross-consistency checks against traditional environmental data sources and expert vegetation mappings support a high reliability for temperature, soil pH, and salt variations based on mobile sensing. Importantly, we can also map environmental factors for which traditional data-sets are very uncertain or lacking and therefore allow new insights, such as disturbance severity and frequency, grazing pressure, mowing frequency, soil disturbance, light, soil moisture, and nutrients.

Three applications will illustrate the potential of mobile sensing: mapping of effective bio-environmental regions, high-resolution analysis of urban environments, and a community engagement to better understand ecosystem-atmosphere carbon and water fluxes measured by FLUXNET.