Demetra Rakosy

Pollination and seed dispersal by animals are key drivers of terrestrial biodiversity and ecosystem functioning. Effective mutualistic interactions rely heavily on temporal and functional- trait matching between plants and animals. While global warming is known to induce shifts in plant traits, the extent and direction in which higher temperatures may systematically alter flower and fruit traits across species in natural habitats remains poorly understood. Using elevation as a proxy for temperature across natural populations, we conducted a meta-analysis evaluating 21 quantitative functional traits (15 floral, 6 fruit) across 82 studies and 161 species. Standardized mixed-effects linear regression models revealed widespread, systemic responses to elevational temperature gradients in both reproductive structures. In flowers, higher temperatures were systematically associated with changes in petal and sepal width and length (and hence morphology), longevity, nectar volume, number of flowers, and inflorescence length. In fruits, elevation was associated with changes in vitamin C content, crop size, weight and width. Taken together, these results demonstrate that warming temperatures exert widespread, multi-axis effects on the morphology, availability, timing, and nutritional quality of both flowers and fleshy fruits. Given that flower and fruit traits are developmentally linked and co-determine animal visitor dynamics, these temperature-driven phenotypic shifts are likely to propagate cascading disruptions throughout plant–pollinator and plant–frugivore interaction networks under continued climate change.

Pollen identification and quantification are essential in ecological and evolutionary research to address plant-pollinator relationships, pollination services, and plant reproduction. Research into pollen transfer patterns has been mainly based on traditional light microscopy, however, it is time consuming, labour intensive, and requires taxonomic expertise. High-throughput methods allow automated pollen identification across large temporal and spatial scales. This study compares the accuracy of species identification and quantification of their relative pollen abundance using traditional microscopy, and two high-throughput methods, namely multispectral imaging flow cytometry (MIFC) and metabarcoding. Method performance was tested using artificial samples with known pollen species composition and pollen samples from pollinators with unknown pollen composition. After checking the agreement against the line of identity, the coefficient of determination (R ² ) values of linear models between the method estimates were compared. Metabarcoding performed best at identifying the taxa from artificial mixtures, while the two other methods assessed the relative abundance most accurately when there was information about species identity. Comparability between methods was overall low when assessing pollen composition on pollinators. To acquire both pollen identity and relative abundance, we recommend a metabarcoding-guided MIFC analysis that can be used as a high throughput approach for pollen research at large spatial and temporal scales.

Anthropogenic change has resulted in pollinator declines and altered plant–pollinator interactions. This may alter pollination services, reducing the reproductive success of plants. Yet few datasets allow us to track changes in pollination services over time. Herbaria provide a unique opportunity to assess pollination services across broad spatial and temporal scales enabling the examination of associated spatiotemporal anthropogenic drivers of change. We quantified changes in pollination services to the orchid genus Caladenia over the past century, a period of rapid land‐use intensification and climate change in Australia. Examining 10,494 Caladenia flowers preserved at the Australian National Herbarium showed a reduction in pollination services totaling > 60% over the whole study period, with rapid declines occurring post 1970. Declines in pollination services occurred across species pollinated by different taxa and with varying threat status. Sexually deceptive species showed more pronounced declines in pollination services than food‐deceptive species, whereas no decline was detected in the self‐compatible species. Land‐use intensity and rising temperatures were significant predictors of changes in pollination service. Our findings provide rare evidence of declines in pollination services and demonstrate the value of herbarium collections in understanding global change.

Insects can respond rapidly to climate change through population fluctuations, range shifts, altered voltinism, life cycle changes, flight period adjustments, behavioural shifts, and changes in habitat or food preference—often varying by region due to local environmental and anthropogenic factors. While the phenological cycles of diurnal lepidopterans have been extensively studied in countries with large monitoring networks, eastern and southeastern Europe remain under-researched. This study provides the first insights into phenological shifts in 16 butterfly species in Cluj-Napoca (Transylvania, Romania) between 1921 and 2023, using a unique dataset combining historical and recent records. The species studied include spring-emerging, multivoltine, and migratory butterflies. Phenological trends were analyzed in relation to long-term climatic data. Results show that spring species now emerge approximately 15 days earlier, and autumn species extend their flight periods by up to 23 days. These changes correlate with multi-decadal trends in temperature and precipitation. We also discuss changes in voltinism and migratory behaviour and the potential impacts of climate change on butterfly populations in the study region.

Anthropogenic change has resulted in pollinator decline and altered plant-pollinator interactions. This may drive widespread declines in pollination and reproductive success of plants, yet few datasets allow us to track changes in pollination services over time. Herbaria provide a unique opportunity to assess pollination services across broad spatial and temporal scales, and the associated spatiotemporal anthropogenic change. We quantified changes in pollination services to the orchid genus Caladenia over the past century, a period of rapid land-use intensification and climate change in Australia. Examining 10,494 Caladenia flowers preserved at the Australian National Herbarium showed a reduction in pollination services totaling > 60 % over the whole study period, with rapid declines occurring post 1970. Declines in pollination services occurred across species pollinated by different taxa and threat status. Sexually deceptive species had more pronounced declines in pollinator services. Historical land-use change, and rising temperatures varied by region and were significant predictors of pollination service decline. Our findings provide rare evidence of declines in pollination services modulated by pollination syndrome and demonstrate the value of herbarium collections in understanding global change.

Pseudophilotes bavius ​​is a butterfly species protected by the EU Habitats Directive. The subspecies P. bavius ​​hungarica, known by the vernacular name Transylvanian Blue, is endemic to the Transylvanian Plain (Transylvanian Plateau) in Romania. Its distribution is limited to dry grasslands on steep, south-facing slopes, always in association with Salvia nutans. Unfortunately, many of the extant populations of P. bavius hungarica are threatened with extinction due to overgrazing by sheep, abandonment of grasslands and afforestation. In order to safeguard this emblematic species, an attempt was made to colonise another suitable habitat patch over 100 km away from the donor sites. Only one year after the translocation of 11 females, a viable core population was formed. In order to strengthen the core population, in 2024, a further six females were translocated. The newly-formed population will increase the resilience of the subspecies and shows a way forward in protecting highly localised, endemic taxa in Romania. The creation of a nature reserve with special protection and conservation measures in the translocation area and the commitment of local stakeholders will ensure the maintenance of the Transylvanian Blue in Romania.

Artificial intelligence (AI) surpasses human accuracy in identifying ordinary objects, but it is still challenging for AI to be competitive in pollen grain identification. One reason for this gap is the extensive trait variation in pollen grains. In classical textbooks, pollen size relies on only 25–50 pollen grains, mostly for one plant and site. Lack of variation in pollen databases can cause limited application of machine learning approaches to real‐world samples. Therefore, our study aims to investigate sources of spatial and temporal pollen trait variation for pollen morphology and fluorescence. For this purpose, 64,001 pollen grains from the four herbaceous and insect‐pollinated plant species Achillea millefolium L., Lamium album L., Lathyrus vernus (L.) Bernh., and Lotus corniculatus L. sampled across four years and seven locations across Central Germany were measured using multispectral imaging flow cytometry. Observed trait variations were very species‐specific; however, for most species, significant differences in spatial as well as temporal variation were found for at least one pollen trait. We could also show that this variability and the identity of a particular sample influence the accuracy of AI classifications and that multiple measurements of different origins provide the most robust AI‐based identifications.

Background: Land management change towards intensive grazing has been shown to alter plant and pollinator communities and the structure of plant-pollinator interactions in different ways across the world. Land-use intensification in Eastern Europe is shifting highly diverse, traditionally managed hay meadows towards intensive pastures, but few studies have examined how this influences plant-pollinator networks. We hypothesized that the effects of intensive grazing on networks will depend on how plant communities and their floral traits change. Methods: We investigated plant and pollinator diversity and composition and the structure of plant-pollinator interactions near Sibiu, Romania at sites that were traditionally managed as hay meadows or intensive pastures. We quantified the identity and abundance of flowering plants, and used transect walks to observe pollinator genera interacting with flowering plant species. We evaluated the effects of management on diversity, composition and several indices of network structure. Results: Pollinator but not plant diversity declined in pastures and both plant and pollinator taxonomic composition shifted. Functional diversity and composition remained unchanged, with rather specialized flowers having been found to dominate in both hay meadows and pastures. Apis mellifera was found to be the most abundant pollinator. Its foraging preferences played a crucial role in shaping plant-pollinator network structure. Apis mellifera thus preferred the highly abundant Dorycnium herbaceum in hay meadows, leading to hay meadows networks with lower Shannon diversity and interaction evenness. In pastures, however, it preferred less abundant and more generalized flower resources. With pollinators being overall less abundant and more generalized in pastures, we found that niche overlap between plants was higher. Discussion: With both hay meadows and pastures being dominated by plant species with similar floral traits, shifts in pollinator preferences seem to have driven the observed changes in plant-pollinator interaction networks. We thus conclude that the effects of grazing on pollinators and their interactions are likely to depend on the traits of plant species present in different management types as well as on the effects of grazing on plant community composition. We thereby highlight the need for better understanding how floral abundance shapes pollinator visitation rates and how floral traits may influence this relationship.

The Omusati region belongs to historic Ovamboland, an area of northern Namibia populated by tribes of the Ovambo group. Four very large African baobabs of Omusati played an important role in historic events of the area, such as the tribal wars and the Namibian War of Independence. The four historic baobabs are the Ombalantu baobab (8 stems; circumference 24.50 m), Okahao baobab (4+ stems; around 25 m), Amadhila baobab (12 stems; 25.35 m) and Sir Howard baobab (9 stems; 31.60 m). Two historic baobabs collapsed totally or partially. The stems of the Amadhila baobab toppled and died in 2021, while 3 stems of the Okahao baobab collapsed a long time ago, but are still alive. Our research aimed to determine the architecture and age of these baobabs. Three baobabs (Ombalantu, Amadhila, Sir Howard) exhibit a closed ring-shaped structure, with a false cavity inside. One baobab (Okahao) had an open ring-shaped structure, before its collapse. Several wood cores were extracted from the baobabs and investigated by radiocarbon dating. The dating results indicate ages of 770 ± 50 years for the Ombalantu baobab, 650 ± 50 years for the Okahao baobab, 1100 ± 50 years for the Amadhila baobab and 750 ± 50 years for the Sir Howard baobab.

Mutualistic interactions between plants and animal pollinators are increasingly under threat through anthropogenic change, and it is critical to understand how temporal changes affect the structure and function of these ecologically important interactions. Because the responses of plant–pollinator interactions to anthropogenic change may take place over decades, historical collections that store information across long time horizons contribute uniquely to our understanding. In this article, we highlight several key questions related to long‐term changes in the structure and function of plant–pollinator interactions. We articulate how research could proceed rapidly via new techniques, greater integration of resources in museum collections along with coincident use of a single data source. We acknowledge the challenges that come with using historical collections and discuss how to minimize them. We provide suggestions that will allow for full utilization of museum resources for addressing a variety of issues regarding plant–pollinator interactions. This perspective paper aims to stimulate new integrative research aimed at understanding temporal patterns in plant–pollinator interactions. Read the free Plain Language Summary for this article on the Journal blog.