Search

Aim: Geomorphological processes profoundly affect plant establishment and distributions, but their influence on functional traits is insufficiently understood. Here, we unveil trait–geomorphology relationships in Arctic plant communities. Location: High‐Arctic Svalbard, low‐Arctic Greenland and sub‐Arctic Fennoscandia. Time period: 2011–2018. Major taxa studied: Vascular plants. Methods: We collected field‐quantified data on vegetation, geomorphological processes, microclimate and soil properties from 5,280 plots and 200 species across the three Arctic regions. We combined these data with database trait records to relate local plant community trait composition to dominant geomorphological processes of the Arctic, namely cryoturbation, deflation, fluvial processes and solifluction. We investigated the relationship between plant functional traits and geomorphological processes using hierarchical generalized additive modelling. Results: Our results demonstrate that community‐level traits are related to geomorphological processes, with cryoturbation most strongly influencing both structural and leaf economic traits. These results were consistent across regions, suggesting a coherent biome‐level trait response to geomorphological processes. Main conclusions: The results indicate that geomorphological processes shape plant community traits in the Arctic. We provide empirical evidence for the existence of generalizable relationships between plant functional traits and geomorphological processes. The results indicate that the relationships are consistent across these three distinct tundra regions and that geomorphological processes should be considered in future investigations of functional traits. [ABSTRACT FROM AUTHOR]

Inter-Specific Facilitation Mediates the Outcome of Intra-Specific Interactions Across an Elevational Gradient We examined the potential for inter-specific interactions to mediate the outcome of intra-specific interactions within the context of plant-plant facilitation. GLO:69VH/01jan21:bes21806-fig-0004.jpg PHOTO (COLOR): . gl Photo 4: Agrostis magellanica and Azorella selago in the fellfield vegetation type on Marion Island. [Extracted from the article]

The flora of sub-Antarctic Marion Island forms part of the unique South Indian Ocean Biogeographic Province, and is under threat from climate change and invasive species. Current information on the flora is necessary to rapidly identify and manage future changes. We conducted a literature search on the taxonomy of indigenous vascular plant species on Marion Island and found nomenclatural changes following taxonomic revisions for Austroblechnum penna-marina (Poir.) Gasper & V.A.O.Dittrich, Carex dikei (Nelmes) K.L.Wilson, Leptinella plumosa Hook.f., Notogrammitis crassior (Kirk) Parris, Phlegmariurus saururus (Lam.) B.Øllg., and Polypogon magellanicus (Lam.) Finot. Additionally, Ranunculus moseleyi Hook.f. was removed from our species checklist due to its long absence in floristic surveys, leaving 21 species in the indigenous vascular plant flora present on Marion Island. We also amplified and sequenced the universal plant barcoding loci rbcL and matK for 19 and 13 species, respectively, and found that ample interspecific genetic distance and minimal intraspecific genetic distance allowed for easy discrimination between species. Lastly, we obtained genome size estimates using flow cytometry for 12 species. Mean 2C genome size for species on Marion Island ranged from 0.44 to 21.44 pg, which is on the lower end of the known range for vascular plant species. We detected two distinct cytotypes in Poa cookii (Hook.f.) Hook.f. and one cytotype in all other species measured. [ABSTRACT FROM AUTHOR]

Biotic interactions can shape species’ distributions through their impact on species’ realized niches, potentially constraining or expanding the range of conditions under which species occur. We examine whether fine-scale plant–plant interactions scale up to shape broad-scale species’ distributions, using Azorella selago, a widespread cushion plant that facilitates other species, and the rest of the vascular flora of sub-Antarctic Marion Island as a model system. We compared the upper elevational distributional limit of each species when growing on vs. away from A. selago to test how the interaction with this cushion plant species affects species’ ranges. Three out of 19 vascular plant species occurred at higher altitudes in the presence of A. selago than in the absence of A. selago: Acaena magellanica (+26 m higher), Colobanthus kerguelensis (+37 m higher), and Lycopodium saururus (+19 m higher). Therefore, A. selago’s fine-scale impacts scaled up to shape the distribution of a subset of the vascular flora of Marion Island. Plant–plant interactions thus have the potential to expand species upper distributional limits by increasing the niche space that a species can occupy, although the influence of these interactions may be strongly species-specific. [ABSTRACT FROM AUTHOR]

Soil seed banks can play an important role in the restoration of degraded ecosystems, especially where indigenous species are well represented in, and invasive species are largely absent from, the seed bank. Here, we studied the potential contribution of the soil seed bank to the restoration of invaded, abandoned agricultural fields in the Eastern Cape, South Africa. We recorded the aboveground cover and belowground abundance of all vascular plant species from 120 quadrats that differ in cover of the extralimital woody invader, Pteronia incana. Our results show that higher cover of P. incana is associated with lower species richness, aboveground cover, and belowground seed abundance. Furthermore, community similarity between the above‐ and belowground component was low, with the seed bank and standing vegetation having only 15 species in common and 49 species being recorded only from the seed bank. We suggest that this large number of seed bank‐only species is a relic of previous vegetation, prior to large‐scale invasion by P. incana. The most important finding from our study is the absence of P. incana from the soil seed bank. This finding, combined with the large number of mostly native species from the seed bank, holds promise from a restoration perspective. However, given the susceptibility of the invaded systems to erosion, coupled with the low grazing value of the seed bank species, we suggest that P. incana removal should be accompanied by both erosion control measures and reseeding with palatable grass species, to secure the livelihoods of local communities. [ABSTRACT FROM AUTHOR]

Aim The Arctic has experienced marked climatic differences between glacial and interglacial periods and is now subject to a rapidly warming climate. Knowledge of the effects of historical processes on current patterns of diversity may aid predictions of the responses of vegetation to future climate change. We aim to test whether plant species and genetic diversity patterns are correlated with time since deglaciation at regional and local scales. We also investigate whether species richness is correlated with genetic diversity in vascular plants. Location Circumarctic. Methods We investigated species richness of the vascular plant flora of 21 floristic provinces and examined local species richness in 6215 vegetation plots distributed across the Arctic. We assessed levels of genetic diversity inferred from amplified fragment length polymorphism variation across populations of 23 common Arctic species. Correlations between diversity measures and landscape age (time since deglaciation) as well as variables characterizing current climate were analysed using spatially explicit simultaneous autoregressive models. Results Regional species richness of vascular plants and genetic diversity were correlated with each other, and both showed a positive relationship with landscape age. Plot species richness showed differing responses for vascular plants, bryophytes and lichens. At this finer scale, the richness of vascular plants was not significantly related to landscape age, which had a small effect size compared to the models of bryophyte and lichen richness. Main conclusion Our study suggests that imprints of past glaciations in Arctic vegetation diversity patterns at the regional scale are still detectable today. Since Arctic vegetation is still limited by post-glacial migration lag, it will most probably also exhibit lags in response to current and future climate change. Our results also suggest that local species richness at the plot scale is more determined by local habitat factors. [ABSTRACT FROM AUTHOR]