Fride Høistad Schei
Research Scientist
Biography
I am a community ecologist broadly interested in how natural and human global change drivers affect populations, communities and ecosystems at different spatial and temporal scales. Currently, I am focusing on forest ecology, conservation, and sustainable management of forest resources.
Keywords: Conservation, continuous cover forestry (CCF), forest ecology, forest certification and long-term changes.
Authors
Fride Høistad Schei Mie Prik Arnberg John-Arvid Grytnes Maren Stien Johansen Jørund Johansen Anna Birgitte Milford Anders Røynstrand Mari Mette TollefsrudAbstract
Climate change and human activities have accelerated the spread of non-native species, including forest pests and pathogens, significantly contributing to global biodiversity loss. Pathogens pose a significant threat to forest ecosystems due to a lack of coevolution with native hosts, resulting in ineffective defence mechanisms and severe consequences for the affected tree species. Ash dieback, caused by the fungus Hymenoscyphus fraxineus, is a relatively new invasive forest pathogen threatening ash (Fraxinus excelsior) with mortality rates in northern Europe reaching up to 80 %. The loss of ash due to dieback has severe ecological implications, potentially leading to an extinction cascade as ash provides crucial habitats and resources for many organisms. Despite this, the consequences of ash dieback on associated communities are largely unknown. To address this, we analysed changes in species richness, vegetation structure, and composition in 82 permanent vegetation plots across 23 Norwegian woodlands. We compared data collected before and 10–14 years after the emergence of ash dieback. In these woodlands, ash significantly declined in cover, leading to changes in tree species composition and facilitating the establishment of other woody tree species like hazel (Corylus avellana) and the invasive species sycamore (Acer pseudoplatanus). Despite these changes in the tree species composition, no significant alterations were observed in the understory plant community, indicating a degree of ecosystem resilience or a lagging community response. At this point, and with our focus on the vascular plants, we do not find support for cascading effects due to ash dieback. However, our findings demonstrate that one invasive species is facilitating the expansion of another, raising concerns about potential ecological imbalance and cascading effects in the future.
Abstract
No abstract has been registered
Authors
Wim De Schuyter Emiel De Lombaerde Leen Depauw Pallieter De Smedt Alina Stachurska-Swakoń Anna Orczewska Balázs Teleki Bogdan Jaroszewicz Déborah Closset František Máliš Fraser Mitchell Fride Høistad Schei George Peterken Guillaume Decocq Hans Van Calster Jan Šebesta Jonathan Lenoir Jörg Brunet Kamila Reczyńska Krzysztof Świerkosz Martin Diekmann Martin Kopecký Markéta Chudomelová Martin Hermy Martin Macek Miles Newman Monika Wulf Ondřej Vild Ove Eriksson Peter Horchler Petr Petrik Remigiusz Pielech Thilo Heinken Thomas Dirnböck Thomas A. Nagel Tomasz Durak Tibor Standovár Tobias Naaf Wolfgang Schmidt Lander Baeten Pieter De Frenne Markus Bernhardt-Römermann Radim Hédl Don Waller Kris VerheyenAbstract
1. Wild pollinators are crucial for ecosystem functioning and human food production and often rely on floral resources provided by different (semi-) natural ecosystems for survival. Yet, the role of European forests, and especially the European forest herb layer, as a potential provider of floral resources for pollinators has scarcely been quantified. 2. In this study, we measured the potential nectar production (PNP) of the forest herb layer using resurvey data across 3326 plots in temperate forests in Europe, with an average time interval of 41 years between both surveys in order to assess (i) the importance of the forest herb layer in providing nectar for wild pollinators, (ii) the intra-annual variation of PNP, (iii) the overall change in PNP between survey periods and (iv) the change in intra-annual variation of PNP between survey periods. The PNP estimates nectar availability based on the relative cover of different plant species in the forest herb layer. Although PNP overestimates actual nectar production, relative differences amongst plots provide a valid and informative way to analyse differences across time and space. 3. Our results show that the forest herb layer has a large potential for providing nectar for wild pollinator communities, which is greatest in spring, with an average PNP of almost 16 g sugar/m2/year. However, this potential has drastically declined (mean plot-level decline >24%). 4. Change in light availability, associated with shifts in canopy structure and canopy composition, is the key driver of temporal PNP changes. 5. Synthesis. Our study shows that if management activities are carefully planned to sustain nectar-producing plant species for wild pollinators, European forest herb layers and European forests as a whole can play key roles in sustaining wild pollinator populations.
