Talk grasslands

Conservation and Management of Alpine Grasslands Based on Long-term Field Observations across North Tibet

by Jianshuang Wu, Friday 27th January 2023

Alpine grasslands at high elevations are vulnerable to human disturbance and climatic fluctuations. The increasing degradation of alpine grasslands threatens the livelihood security of Tibetan herder communities. It becomes urgent to quantify how climate change (warming and altered precipitation) and human endeavours (payment policies for decreasing livestock numbers, altering livestock composition, and reducing grazing duration) affect ecosystem structure and functions of different alpine grassland types (meadow, steppe, and desert-steppe) in North Tibet. Jianshuang and his team conducted field surveys of species composition, plant functional traits and aboveground biomass for 15 years at pairs of fenced vs grazed sites to quantify fencing effects on meadows, steppes, and desert-steppe. Based on this long-term dataset, they also validated remote-sensing products for alpine grasslands in North Tibet. The relative contributions of climate change and human activities to the dynamics of alpine grasslands during the last decades in North Tibet and even the entire Qinghai-Tibetan Plateau were disentangled by using statistical methods and remote-sending products. The findings of field observations and remote-sensing monitoring across different grassland types assist in developing conservation and management payment policies for alpine grasslands in the Tibetan Autonomous Region of China.

Flower-insect interactions in mountain ecosystems

by Elena Eustacchio and Marco Bonelli, Friday 24^th February 2023

Plants and arthropods interact with each other creating complex networks that can be essential for ecosystem functioning and stability, as in the case of pollination networks. It is estimated that about 90% of existing flowering species are pollinated by animals, mostly insects. Conversely, many arthropods depend on flowers for their existence. In some respects, however, the knowledge about flower-insect interactions is still partial and incomplete. For instance, it is known that biotic interactions in mountain ecosystems are currently threatened by climate change, but the knowledge about flower-insect interactions in these environments is still scarce. This may be due to different reasons, such as a perceived lack of short-term economic interest and logistical difficulties in conducting research in these harsh environments. In this context, our work aims to evaluate plant and arthropod interactions with a focus on flower-visiting arthropods in different Alpine ecosystems. In particular, we started our studies focusing on the early season community of flower-visiting arthropods in high-altitude environments, as the beginning of the season is a critical moment for possible climate change-driven mismatches between plants and pollinators. This study also allowed us to develop an innovative approach to investigate biotic interactions in alpine environments. In particular, we proposed to integrate manual sampling and in-field video observations. The first method allows us to identify visiting arthropods on a fine scale and build quali-quantitative plant-pollinator networks. Conversely, video observations provide information on arthropod behavior and activity to hypothesize their ecological roles.Therefore, we expanded our research to understand how flower-visitor network changes along an altitudinal gradient, during the plant growing season and among different land management types in order to identify the focal plant and arthropod species responsible of network structure and stability.. Our studies can be helpful to provide novel information about little-known aspects of plant-arthropod interactions and pollination ecology in mountain ecosystems.

Ancient grasslands –  land use legacies

by Sara Cousins Friday 17^th March 2023

Ancient grasslands have some of the highest plant species richness in Europe. A long continuity of management and spatial connectivity is a prerequisite for the high species richness we can find there today. Changes in species composition following landscape change often take time to become apparent, with communities slow to become equilibrated to the altered landscape composition as extinction debts and colonisation credits are gradually settled. Understanding the response of species over time following landscape change is therefore essential to accurately assess its impacts and devise effective management measures. Despite this, the factors which control the magnitude of time lags and the rate at which they are resolved still remain unclear. Historical cadastral maps have been used to investigate continuity and management patterns in space and effects of habitat fragmentation on species richness today but also the restoration potential of grasslands and small remnant grassland habitats in the future.

Drivers of insect decline in grasslands: mechanisms and solutions

By Nadja Simons (08 December 2020)

Insects are the most diverse animal group on the planet, can be found in all ecosystems, and play a major role in almost all ecosystem process. Despite their importance for healthy ecosystems and many ecosystem services, their numbers and diversity is declining rapidly and to worrying extend. In this talk, Nadja guided us to take a closer look at the insect (and spider) communities on managed grasslands in Germany. She highlighted the current trend of insect diversity, discussed the effect of management type and intensity on insect diversity as well as the underlying mechanisms. Moreover,  she provided insights into possible solutions for biodiversity-friendly grassland management.

Recent developments of the EUNIS classification of European habitats

By Milan Chytrý (12 Jan 2021)

The EUNIS Habitat Classification, managed by the European Environment Agency, is a widely used reference framework for natural, semi-natural and man-made habitat types in Europe. Recently, this classification was extensively revised and updated. One of the main problems of the earlier EUNIS versions was the lack of clear definitions of individual habitat types that would enable a reliable assignment of each site to a habitat type.

Therefore, an expert group including MilanChytrý from the IAVS Working Group European Vegetation Survey has been working since 2012 for the European Environment Agency on improvements of EUNIS. They proposed more meaningful concepts of many habitat types, developed their unequivocal definitions and delivered characteristics of individual habitat types based on reliable data. They developed the expert system called EUNIS-ESy for automatic classification of European vegetation plots to EUNIS habitats. They have used this expert system to classify approximately 1.3 million vegetation plots from the European Vegetation Archive. Then they used these plots to produce statistically derived characteristic species combinations and distribution maps for more than 200 EUNIS habitat types. In his presentation, Milan Chytrý summarized the main features of the revised EUNIS classification and demonstrate how to use the EUNIS-ESy expert system. See also https://vegsciblog.org/2020/08/21/filling-empty-boxes-european-habitat-classification-eunis/.

Ancient and modern grasslands: plant communities as bioassays

By Honor C Prentice

04 February 2021 Thursday 14.00 (CET)

In her talk, Honor showed different ways in which plant community composition can be used as a tool to investigate ecological and population-genetic questions. She gave examples from the grasslands and “alvar” heaths on the Great Alvar of Öland where her team characterized the ages of the grassland fragments (using historical maps, aerial photos and satellite scenes) and explored different aspects of plant community assembly as well as the historical and edaphic factors that are associated with the occurrence of individual species.