Biology subjects

Farkas, L. Z.

Publications and source records attributed to Farkas, L. Z..

3 recordsLinked to original sources

bioRxiv2025

Different dispersal rates and declining climate suitability shape future vegetation compositions across the Arctic: implications for the boreal forest - tundra boundary

AimWe investigate how species-specific dispersal abilities might influence future Arctic plant distributions and large-scale dynamics at the boreal forest - tundra boundary until 2100 Locationcircumpolar terrestrial Arctic (boreal forest, taiga and tundra) Taxon1,550 plant species MethodsWe developed climate-driven species distribution models (SDM) to predict species-specific emerging climate niches under different climate scenarios. The model was parameterized using occurrence data from the Global Biodiversity Information Facility database (GBIF) and temperature and bioclimatic variables from the CHELSA data set. Dispersal rates were assigned to each species using a trait-based approach and were used to predict future habitat with a distance-based probability over time. ResultsPlant species are predicted to occupy on average only 12.3% (1.5 - 53.9 95% CI) of their emerging climate niches, with half of the species unable to colonize new habitat by 2100 due to limited dispersal distances. In dispersal limited predictions migration to higher altitudes played a greater role than northward shifts. Decolonization by species (extirpation) due to decreasing climate suitability had a larger effect on species composition change compared to dispersal limitations. Boreal tree species were predicted to expand into the tundra shrinking the treeless areas. Main conclusionsFuture plant species distributions and resulting large-scale compositions are affected by species-specific dispersal rates. Even though new suitable niches emerge prominently towards the north, higher altitudes might be more relevant given their accessibility by dispersal over the next century. Although climate niche dynamics could support higher plant species richness across the Arctic, overall richness is expected to decline with climate warming due to dispersal limitations. The colonization of new habitats via dispersal in combination with the decolonization of former habitats due to declining climatic suitability on species level are predicted to cause large-scale changes in species composition, especially at the boundary between the boreal forest and the tundra biome.

ecology↗

bioRxiv2025

Dynamic connectivities of plant metacommunities at a millennial time-scale: the Beringia testbed

Ecological connectivity shapes ecosystem responses to climate change and is thought to underpin stability, yet its millennial-scale dynamics remain poorly resolved. We asked how spatial and temporal connectivity of plant metacommunities changed over the last 40 ka and which processes drove it. We analysed and compiled plant sedimentary DNA from 20 lake cores across Beringia (Siberia, Alaska) to investigate community dynamics and, for a high-resolution subset, applied beta- and zeta-diversity to track connectivity. Vegetation changed coherently across the glacial-Holocene transition, with trait shifts mirroring functional composition. Connectivity peaked during the late MIS3 and Last Glacial Maximum--likely aided by the Bering Land Bridge, mass effects and facilitation--collapsed during the Deglacial with rapid turnover, and rebounded in the Holocene as shrub and boreal communities expanded. Temporal zeta within sites exceeded spatial zeta, indicating strong local persistence and resilience. Tundra sites uninvaded by forest maintained continuous species pools. Overall, these patterns underscore the value of a metacommunity perspective for assessing millennial-scale connectivity changes.

ecology↗

bioRxiv2025

Woody plant encroachment enhances negative interactions in Arctic plant communities over the last 24,000 years

Woody taxa encroachment in the Arctic has been widely observed. However, it remains uncertain how plant interactions are affected by such encroachment due to the lack of long-term observational data. Here, we reconstruct plant composition and functional trait turnover during post-glacial woody encroachment using sedimentary ancient DNA from nine lakes in the Siberia-Alaska region. Environmentally constrained null models are applied to partition plant interactions from the pure environment driven plant co-occurrence signal. Our results show that plant interactions shifted from predominantly positive interactions (e.g. nurse-plant facilitation) during the glacial period to negative interactions (e.g. competition) during the Holocene. This shift coincided with a community transition from herbaceous to woody taxa, leading to an increase in average plant height and root length, as evidenced by leveraging plant trait information. We suggest that climate (an external factor) and plant interactions (an internal process) jointly supported rapid and widespread woody taxa expansion at the end of the last glacial, which may provide an analogy with contemporary "arctic greening". In turn, woody encroachment is likely to constrain the geographical ranges of native species, increasing the risk of local native taxa loss, while enhancing beta diversity.

ecology↗