International Mountain Conference

Abstract ID 716 | Date: 2022-09-14 10:12 – 10:24 | Type: Oral Presentation | Place: THEOLOGIE – Madonnensaal |

Saccone, Patrick (1); Steffens, Malena (1); Steinbauer, Klaus (1,2); Lamprecht, Andrea (1); Winkler, Manuela (1)

Intraspecific trait variability (ITV) is an important component of the plant species responses to climate changes. Alpine ecosystems are exposed to drastic changes, and ITV could mitigate the effects on plant communities. This study focused on the intraspecific variability of the specific leaf area, leaf dry matter content, and vegetative height of Carex firma and Dryas octopetala along a 500 m elevation gradient in the Eastern Austrian Alps. Slope, vegetation cover, exposition, and community average of ecological indicators were considered as environmental factors. We found large ITVs for both species and no clear patterns along the elevational gradient. Instead, soil resources and thermic indicators explain the patterns the best. Both species are similarly ranked among the conservative species in the surveyed communities and showed similar patterns of response despite their affiliations to different functional types. Our results suggest that the common hypothesis of biodiversity homogenization of mountains with climate warming does not consider enough what really matters to plants, i.e. the habitat conditions. Elevation appeared as one component of the energetic gradient highlighted in this study rather than an integrative ecological gradient. It is likely that the environmental heterogeneity of alpine ecosystems is buffering their functional diversity loss.

Abstract ID 192 | Date: 2022-09-14 10:24 – 10:36 | Type: Oral Presentation | Place: THEOLOGIE – Madonnensaal |

Apple, Martha Elizabeth (1); Gallagher, James Hr (2); Winscot, Kurtiss (2); Apple, Charles J (3)

The GLORIA, (Global Observation Research Initiative in Alpine Environments) is a vast, world-wide observation network for long-term monitoring of alpine plants and temperature on mountain summits. The SW Montana GLORIA Target Region (2008-2022 and onward) in the Pioneer Mountains is on Mt. Keokirk (2987 m, 45.5938° N, -112.9510° W) and Mt. Fleecer (2873 m, 45.8264°N, 112.8019°W), where we measure soil temperature hourly with Hobo Tidbit v2 temperature loggers 5-10 cm underground, and at each cardinal direction 5 m beneath four summits along an elevational gradient from treeline to the alpine zone. We surveyed the distribution and relative percent cover (RPC) of plant species and their qualitative functional traits upon establishment of the site and at five-year intervals.

Shifts in the distribution and RPC of plant species and functional traits occurred between 2008-2019 at the SW Montana GLORIA Target Region on Mt. Fleecer and on Mt. Keokirk. These shifts included decreases and increases in abundance of species and functional groups, with the most pronounced changes at Mt. Keokirk's southern aspect, (2987 m), where summer soil temperatures increased and winter soil temperatures decreased from 2013-19. The RPC of Potentilla nivea, a stoloniferous member of the rose family, increased from 5.75 +/- 2.8 (2013) to 14.00 +/- 6.68 (2019) and by over 50% in some 1M X 1M quadrats. This suggests increased clonal reproduction via stolons with higher temperatures, although a different trait of P. nivea may have contributed to its increased RPC. However, the RPC of rhizomatous species decreased (12.37 to 4.87%), which is linked to the decreased RPC of rhizomatous monocots, but which may signify changes in clonal mechanisms with increased temperature. When considering all four aspects of Mt. Keokirk from 2013-2019, vascular plant cover decreased (44.52 to 38.87%), with monocots decreasing (11.37 to 3.7%) but dicots increasing slightly (29.98 to 33.12%). Morphology shifted, with decreases in mat-forming (13.25 to 6.00%) and cushion plants (8.12 to 5.00%). The increased RPC of AM plants (33.00 to 40.48%) suggests that temperature influenced AM symbioses on Mt. Keokirk. Changes in the RPC of species and functional traits co-occurred with increasing summer temperatures at the SW Montana GLORIA Target Region.

Abstract ID 790 | Date: 2022-09-14 10:36 – 10:48 | Type: Oral Presentation | Place: THEOLOGIE – Madonnensaal |

Nicklas, Lena (1); Bertol, Nils (1); Mallaun, Martin (1); Trenkwalder, Iris (1); Unterluggauer, Peter (1); Wipf, Sonja (2,3); Erschbamer, Brigitta (1)

In mountain habitats, where life is limited by cold temperatures, it seems obvious that climate warming has a strong impact on the composition of ecosystems. Long-term monitoring studies like the GLORIA project are crucial to understand diversity changes and species range shifts on mountain summits, elucidate the processes leading to these changes, and understand the time scales over which they are acting. Up to date a worldwide vascular plant species increase on mountain summits has been observed and attributed to warming temperatures. But the species increase might only be temporal phenomenon and cryophile species are expected to be threatened by competitive displacement and physiological constraints in the near future. Until now, time series that monitor vegetation change are often too short to detect and generalize patterns of winner or loser species within alpine communities.

Therefore, we complemented a 14-year time series of summit vegetation change with a space-for-time approach along gradients below these summits in two GLORIA regions in the Central and Southern European Alps. To combine patterns of change and patterns of elevational distribution, we recorded vascular plant species composition every 50 vertical meters from the summits down to the treeline. By using indicator values and plant strategy types, we analysed changes in community weighted means and differences of the species composition along the time and elevation gradient. Through an analysis of distribution patterns and functional traits of the recorded species, we expected to identify potential migrators likely to approach the summits in the near future. Further, we tested the hypothesis whether successfully migrating species from lower elevation might originate from nutrient-richer sites and are more widespread and competitive compared to the alpine resident species.

Results from the transects and summit monitoring showed clear thermophilization trends. Competitive species played a minor role in the communities of the summits. Especially at the lower summits the proportion of thermophilic species increased significantly over time. Here, thermophilic species limit cryophilic species in near future. This process will be intensified due to increasing abundance of dwarf shrubs and trees.

The knowledge about the species and their traits will be highly valuable for interpreting future monitoring results. Especially for conservation issues, such detailed local studies are crucial as they can detect species at risk. Moreover, the functional approach gives an idea which consequences the changes will have for the whole ecosystem and its services.

Abstract ID 885 | Date: 2022-09-14 10:48 – 11:00 | Type: Oral Presentation | Place: THEOLOGIE – Madonnensaal |

Joseph, Lumnesh Swaroop Kumar (1); Cremonese, Edoardo (2); Migliavacca, Mirco (3); Schaumberger, Andreas (4); Bahn, Michael (1)

Mountain grasslands are exposed to multiple global changes, which can cause significant phenological shifts. While the individual effects of elevated CO₂, climate warming and drought events on grassland phenology have been studied to some degree, understanding of the interactive effects of these global change drivers is still limited. In a multifactor global change experiment on a managed montane grassland typical for many parts of the Alps, with 3 periodic cuts (end of May, July, and September), we tested the individual and combined effects of elevated CO₂ (eCO₂; +300 ppm), warming (eT; +3°C) and severe summer drought on canopy- and species-level phenology. We classified the data into 4 growing periods based on the cuts and derived the canopy-level phenological transition dates from Green Chromatic Coordinates (GCC) time series calculated from phenocam images. On weekly basis field phenological observations were conducted to monitor species-specific phenological shifts under different treatment conditions using BBCH codes. Our preliminary findings show that warming, both individually and when combined with elevated CO₂, led to early green-up, while summer drought, both under ambient conditions and when combined with warming and elevated CO₂, advanced senescence. Across all global change treatments non-leguminous forbs expressed earlier green-up and earlier senescence in comparison to grasses and legumes, though effects were also strongly driven by species identity. Overall, our first findings suggest distinct non-additive effects of interacting global change drivers on the phenology of mountain grassland.

Abstract ID 264 | Date: 2022-09-14 11:00 – 11:12 | Type: Oral Presentation | Place: THEOLOGIE – Madonnensaal |

Maihoff, Fabienne

Global warming is assumed to restructure mountain insect communities in space and time. Theory and observations along climate gradients predict that insect abundance and richness, especially of small-bodied species, will increase with increasing temperature. However, the specific responses of single species to rising temperatures, such as spatial range shifts, may weaken such prediction, asking for intensive monitoring of real-world communities over time. Here, we examined the temporal and spatial change in wild bee communities and its drivers along two largely well-protected elevational gradients (alpine grassland vs. prealpine forest), each resampled within the last decade. Along both gradients, we detected clear upward shifts in bee communities, with cold-adapted bumblebee species reacting particularly sensitive, demonstrating the speed with which mobile organisms can respond to climatic changes. Mean annual temperature (MAT) was identified as the main driver of species richness in both regions. Accordingly, and in large overlap with expectations under climate warming, we detected an increase in bee richness and abundance, and an increase of small-bodied species in low- and mid-elevations along the grassland gradient. While changes in upward shifts, species richness, abundance and body size in the prealpine forest gradient were partly consistent with the alpine grassland system, they were generally weaker, which could be due to a much less severe warming trend than in the alpine grassland system or due to the variable and possibly confounding effect of canopy cover. Our study highlights the use of accurate assessed abundance data revealing rapid changes in bee communities over only one decade. We conclude, that in well-protected temperate regions, small-bodied bees may initially profit from warming temperatures, by getting more abundant and diverse.

Abstract ID 252 | Date: 2022-09-14 11:12 – 11:24 | Type: Oral Presentation | Place: THEOLOGIE – Madonnensaal |

Schuchardt, Max (1); Berauer, Bernd (2); Jentsch, Anke (1)

Warming of mountain regions is projected to be three times faster than the global average likely affecting ecosystem resilience and functioning. In recent years, plant functional traits have become the common currency to measure functional diversity. Yet, little is known how functional traits of grassland communities will change under altered climatic conditions. Here, we have translocated intact plant soil mesocosms from two mountain habitats downslope to simulate their potential local future climate (warming and drought). Moreover, we have translocated mesocosms of low land plant communities upslope to simulate the upward expansion of species distribution. Preliminary results indicate an increase in functional richness, no matter if plant communities have been moved down- or upslope. Underlying drivers of increasing functional richness are likely species turnover under warming and species plasticity under cooling.

Abstract ID 163 | Date: 2022-09-14 11:24 – 11:36 | Type: Oral Presentation | Place: THEOLOGIE – Madonnensaal |

Unterholzner, Lucrezia (1,2); Prendin, Angela Luisa (3,2); Dibona, Raffaella (2); Roberto, Menardi (2); Casolo, Valentino (4); Gargiulo, Sara (5); Boscutti, Francesco (4); Marco, Carrer (2)

In the nowadays context of climate change, tundra ecotones are facing an accelerating advance of the spring snowpack melting and, in turn, a lengthening of the growing season, with noticeable effects on vegetation. Besides summer temperature, also winter precipitation has been recently identified as a key factor in determining tundra shrub growth and shaping physiology responses. Yet, uncertainties still exist on the effects of different snowpack duration on long-living plants, specifically on intra-specific and long-term responses variability when considering multiple functional traits adjustments. To deepen the shrub-snow persistence associations, we set up a 3-years snow manipulation experiment at high elevation on Juniperus communis L., a typical tundra species and the conifer with the world largest distributional range. We tested primary shoot growth, leaf area, stomatal density, leaf dry weight and leaf non-structural carbohydrate content on plants subjected to advanced, natural, and postponed snow-free period. Shrubs under short-lying snowpack showed enhanced elongation of new shoots and increased stomatal density. On the contrary, shrubs under extended snow cover duration seemed to counterbalance the shorter growing season allocating more resources on growth. Accordingly, these plants showed larger leaves and low leaf starch content at the beginning of the vegetative season. Moreover, the divergence between treatments responses resulted evident the first year of experiment but slightly weakened over time, suggesting a gradual acclimation to new conditions. In view of future further warming, these results are in accordance with the prediction of shrub biomass increase within the tundra ecotone. However, the whole picture is not complete yet, and additional studies should concentrate on the long-term fading in the climate sensitivity and on community level responses.

Abstract ID 547 | Date: 2022-09-14 13:30 – 13:42 | Type: Oral Presentation | Place: THEOLOGIE – Madonnensaal |

Anadon-Rosell, Alba (1,2); Casanovas, Amanda (3); Ninot, Josep M. (3); Illa, Estela (3); Pérez-Haase, Aaron (3); Kreyling, Jürgen (2); Martínez-Vilalta, Jordi (1); Wilmking, Martin (2)

The study of plant functional traits has become a widely used approach to investigate ecosystem functioning and ecosystem responses to environmental changes. While numerous studies have focused on plant trait variability between individuals of different species (interspecific variability) less attention has been given to intraspecific and intraindividual variability. We aimed to assess the sources of trait variability among different levels of organisation (species, population, clone, ramet) in clonal dwarf shrubs of cold ecosystems, with special focus on intraindividual variability. For this, we sampled four species, Dryas octopetala, Empetrum hermaphroditum, Vaccinium myrtillus and Vaccinium uliginosum in three locations along elevation gradients in the Pyrenees. At each location, we selected four clones of each species and sampled five ramets within each clone. We measured height, total leaf biomass and the Huber value (sapwood area:leaf area) for each ramet, and we measured specific leaf area and leaf dry matter content in five leaves of each ramet. Preliminary results show that although trait variability remains the largest at interspecific level, the contribution of each organisation level within species differed substantially between the study species. For some species and traits, inter- and intraindividual variability was larger than the variability explained by elevation, and some species showed a remarkably high intraindividual (intraclonal and/or intraramet) variability. We discuss the importance of evaluating the sources of intraspecific variability in trait-based studies aiming to understand ecological patterns at community and ecosystem scale, and the implications of our results for alpine plant species under a changing climate.

Abstract ID 893 | Date: 2022-09-14 13:42 – 13:54 | Type: Oral Presentation | Place: THEOLOGIE – Madonnensaal |

Rondinel Mendoza, Katy Virginia; Marín Rodulfo, Macarena; Cañadas, Eva; Lorite Moreno, Juan

La fenología vegetal es el estudio del momento estacional de los eventos del ciclo de vida y es una poderosa herramienta para evaluar el impacto del cambio climático en las plantas, como un indicador confiable del cambio climático actual para evaluaciones de alerta temprana. En el marco de Smart EcoMountains, el Centro Temático de Ecosistemas de Montaña de LifeWatch-ERIC (Sierra Nevada, España), se han recogido datos de fenología de especies endémicas de Sierra Nevada a partir de muestras de herbario mediante observación "in situ", y digitalización Inspección de muestras de herbario. Recolectamos datos de 5,464 especímenes de herbario pertenecientes a 120 especies endémicas y cubriendo un lapso de tiempo de 184 años. De cada uno de estos ejemplares inferimos la fenologia de floracion y fructificacion,

Como resultados preliminares, encontramos una clara tendencia a adelantar los eventos de floración y fructificación (es decir, en los últimos 100 años, la fecha promedio del pico de floración se ha adelantado 45 días), indicando un claro cambio en los eventos fenológicos de las especies evaluadas. Además, obtuvimos patrones contrastantes a lo largo de los gradientes altitudinales analizados.

Estos resultados pueden mejorar la comprensión de los cambios en la fenología de las plantas bajo el escenario actual de cambio global en las zonas montañosas. Por lo tanto, sirven como indicadores de alerta temprana, especialmente útiles para estimar los impactos de los cambios en los ecosistemas y promover medidas apropiadas de mitigación y adaptación.

Abstract ID 244 | Date: 2022-09-14 13:54 – 14:06 | Type: Oral Presentation | Place: THEOLOGIE – Madonnensaal |

Rana, Nidhi (1); Uniyal, V.p (1); Rayal, Rajesh (2)

Fireflies are flashing beetles, under the family Lampyridae, forming a recreational part of a natural landscape and ecosystem health. Their population is declining rapidly, while the status is still data deficient in India. Several factors have been highlighted and held responsible for their decline, from which night pollution stands out as a new threat, as fireflies reproduction depends on their bioluminescence. Fireflies can present a good model, to explore the night light effect on nocturnal wildlife. However, not much attention has been given to these magnificent beetles. The current study was conducted in tropical moist and tropical dry deciduous forest dominated by Sal (Shorea robusta), semi-urban and urban areas of Doon valley. Total 48 sampling plots (100m X 100m) with nested quadrate (25m X 25m) were laid to monitor species diversity, abundance, and vegetation types of the sampling plots. Fireflies diversity and abundance were evaluated using sweep net, handpicking, manual counting, and digital photography methods. Three species belonging to two genera (Assymetricata circumdata, Assymetricata ovalis, and Lamprigera tenebrossa) were found in the sampling areas from which L. tenebrossa and A. circumdata were only recorded from the semi-urban area. Abundance was highest in the forest edges, as it does not receive much human interference while the population in semi-urban and urban areas was restricted to agricultural fields and small patches of Lantana camara and Parthenium hysterophorus respectively. The valley is facing high pressure of urbanization resulting in changes in the landscape due to habitat fragmentation and night light intensity impacting the population of fireflies. Thus, the fireflies population can be used as bioindicators to evaluate the changes in an ecosystem.

Abstract ID 245 | Date: 2022-09-14 14:06 – 14:18 | Type: Oral Presentation | Place: THEOLOGIE – Madonnensaal |

Purohit, Abha; Uniyal, V.p.

Study on foraging behaviour of bumblebees in Doon Valley, Uttarakhand, Western Himalaya, India

Abha Purohit and V. P. Uniyal

Wildlife Institute of India, Chandrabani, Dehradun, Uttarakhand, India

The Himalayan ranges represent a diversified and complex system of both physical and biological attributes. It is unique and rich in floral and faunal diversity. Pollinators are one of the important aspects of Himalayan biodiversity playing vital role in crop pollination and as ecosystem service providers. Foraging strategy and success define pollinator's capability to survive and reproduce. Due to urbanization and various anthropogenic pressures, pollinators are declining globally. Present study has been conducted on the foraging behavior and cause of decline of bumblebees (order Hymenoptera, family Apidae) in Doon valley of Dehradun district of Uttarakhand, situated in the foothills of outer Himalayan region surrounded by agroecosystems and subtropical temperate landscape. The study is conducted in four different habitats viz riverine; agriculture; forest and semi urban areas. The thermoregulatory ability of bumblebees makes them an efficient pollinator in the high altitude and cold ambient temperatures of the Himalayan region. They are generalist forager and can forage on a wide range of plants. However, some plants do rely on bumblebees to achieve pollination. Loss of bumblebees can have far ranging ecological impacts due to their role as pollinators. It is studied that Bombus haemorrhoidalis Smith is the predominant species of bumblebees in Doon valley and its preferred foraging plant species in the study areas are Cirsium arvense (Asteraceae), Lantana sp. (Verbenaceae), Tropaeolum majus (Tropaeolaceae), Solanum melongena (Solanaceaa) and Tecoma stans (Bignoneaceae). Their foraging activity depends on seasonal availability of floral resources in the study area. It is observed that with the availability of similar foraging plants and climatic conditions there was an abundance of bumblebees in a particular habitat whereas they were absent from another habitat in the same altitude. This could be due to anthropogenic activities in the valley such as urbanization and increased use of fertilizers which is causing threat to its ecological balance. The study is undergoing to find out the causable factors of their absence and decline from the landscape.

Key words: Bumblebees, pollinators, foraging behaviour, floral resources,    

                     Doon Valley.

Abstract ID 872 | Date: 2022-09-14 14:18 – 14:30 | Type: Oral Presentation | Place: THEOLOGIE – Madonnensaal |

Njogu, Antony

African sky islands (alpine zones) hold the key to understanding the impacts of climate change on tropical ecosystems. Select endemic alpine plants could be used for long term monitoring of changing plant habitat range size, physiology and functional traits in response to climate change. We studied morphological, leaf stoichiometric and leaf carbon isotope variation of two endemic species Lobelia gregoriana and Dendrosenecio keniensis along their full elevation range size in Mount Kenya. The objective of this study was to assess the adaptive features that make these giant plants survive the harsh alpine environmental conditions. Our study design involved setting up ninety 10 by 10 plots from 3500 m to 4300m. We measured functional traits plant height, leaf area, thickness, dry weight, specific leaf area, leaf nitrogen, carbon, phosphorous and Leaf δ13C content. We found that Dendrosenecio keniensis had wool-like pubescent leaves while L. gregoriana had mucilage packed succulent and waxy cuticle leaves to avoid freezing. Both species exhibited reduced metabolic rates as shown by the low leaf phosphorous content. Our results also showed that changes in morphology and leaf stoichiometry were determined by a combination of climate, soil and topographic variables that change along elevation on Mount Kenya. There was a leaf δ13C enrichment of 1.76 ‰ km−1 and 1.62 ‰ km−1 with altitude for D. keniensis and L. gregoriana, respectively. Leaf δ13C exhibited a depletion of −0.37 ‰ per °C increase of mean annual temperature along the altitude gradient for D. keniensis and −0.34 ‰ per °C increase for L. gregoriana. The observed changes in morphology, leaf stoichiometry and leaf δ13C along the elevation gradient were mostly associated with low alpine temperatures. This research forms a basis for the use of endemic species to track environmental changes by assessing their elevation range size over time. Studying the morphological changes of these species in relation to climate change could help understand how tropical mountain vegetation would adapt over time in respect to the projected rise in global temperatures.

Abstract ID 751 | Date: 2022-09-14 14:30 – 14:42 | Type: Oral Presentation | Place: THEOLOGIE – Madonnensaal |

Jaroszynska, Francesca (1,2,3); Rixen, Christian (1,4); Woodin, Sarah (3); Lenoir, Jonathan (5); Wipf, Sonja (1,4,6)

How does plant performance change over time, along with changes in elevational distribution? Analysing intraspecific trait variation along an abiotic gradient extracted from herbarium records offers a way to observe such changes in plant performance over time.
We selected four species — Poa alpina and Polygonum viviparum typically found in subalpine meadows, and Cardamine resedifolia and Ranunculus glacialis, typically found in higher-alpine scree habitats — differing in how successfully they have shifted upwards and colonized new summits. We measured growth and reproductive performance traits from herbarium records collected between 1880 and 1950, and from individuals re-sampled in 2014 along >1500 m elevation within the same region in the Swiss Alps, to analyse shifts in the distribution of traits along the studied elevation gradient over time.
Reproductive traits and vegetative height largely decreased with elevation. P. viviparum and P. alpina trait values generally increased over time; those of C. resedifolia (all traits) and R. glacialis (reproductive traits) decreased. Changes over time varied along the elevation gradient: P. viviparum traits and P. alpina reproductive height increased at lower, but not higher elevations. Conversely, R. glacialis reproductive traits and most C. resedifolia traits decreased over time at lower, and increased or converged at higher elevations. In 2014, at lower elevations, species mainly occurred on their typical substrate types of organic soil and scree, respectively, but occurrence on other substrates increased with elevation for all species.
The contrasting trends in trait values of meadow and scree species at the lower elevation over time exemplify how climate warming is favouring generalist species from lower elevations at the expense of more specialised alpine species. At higher elevations, for one of the meadow species this process was limited by a lack of suitable substrate (organic soil). Further warming may confine the distribution of high-alpine plant species to even higher elevations, or to microclimates and substrates on scree and rock that are currently difficult to colonise by lower-alpine species.

Abstract ID 468 | Date: 2022-09-14 14:42 – 14:54 | Type: Oral Presentation | Place: THEOLOGIE – Madonnensaal |

Rixen, Christian (1); Wipf, Sonja (2); Rumpf, Sabine (3); Giejsztowt, Justyna (4); Millen, Jules (4); Morgan, John (5); Nicotra, Adrienne (6); Venn, Susanna (7); Zong, Shengwei (8); Dickinson, Katherine (9); Freschet, Gregoire (10); Kurzböck, Claudia (1); Ji, Lin (11); Pan, Hongli (12); Pfund, Beat (1); Quaglia, Elena (13); Su, Xu (14); Wang, Wei (15); Wang, Xiangtao (15); Yin, Hang (16); Deslippe, Julie (4)

Climate warming is shifting the distributions of mountain plant species to higher elevations. Cold-adapted plant species are under increasing pressure from novel competitors that are encroaching from lower elevations. Plant capacity to adjust to these pressures may be measurable as variation in trait values within a species. In particular, the strength and patterns of intraspecific trait variation along abiotic and biotic gradients can inform us whether and how species can adjust their anatomy and morphology to persist in a changing environment.

Here, we tested whether species specialized to high elevations or with narrow elevational ranges show more conservative (i.e. less variable) trait responses across their elevational distribution, or in response to neighbours, than species from lower elevations or with wider elevational ranges. We did so by studying intraspecific trait variation of 66 species along 40 elevational gradients in four countries in both hemispheres. As an indication of potential neighbour interactions that could drive trait variation, we also analysed plant species' height ratio, its height relative to its nearest neighbour.

Variation in alpine plant trait values over elevation differed depending on a species' median elevation and the breadth of its elevational range, with species with lower median elevations and larger elevational range sizes showing greater trait variation, i.e. a steeper slope in trait values, over their elevational distributions. These effects were evidenced by significant interactions between species' elevation and their elevational preference or range for several traits: vegetative height, generative height, specific leaf area and patch area. The height ratio of focal alpine species and their neighbours decreased in the lower part of their distribution because neighbours became relatively taller at lower elevations. In contrast, species with lower elevational optima maintained a similar height ratio with neighbours throughout their range.

We provide evidence that species from lower elevations and those with larger range sizes show greater intraspecific trait variation, which may indicate a greater ability to respond to environmental changes. Also, larger trait variation of species from lower elevations may indicate stronger competitive ability of upslope shifting species, posing one further threat to species from higher ranges.

Abstract ID 428 | Date: 2022-09-13 18:05 – 18:07 | Type: Poster Presentation | Place: SOWI – Garden |

Rüthers, Jana H. (1); Bakker, Lena (2); Kjær, Sigrid Trier (1); Doetterl, Sebastian (1); Fior, Simone (1); Frossard, Aline (3); Magnabosco, Cara (2); Van De Broek, Marijn (1); Westergaard, Kristine (4); Alexander, Jake (1)

The Arctic has been warming faster than the global average during the last decades, resulting in the temporal and spatial expansions of vegetation, termed "Arctic Greening". This process arises from higher temperatures, prolonged season length and greater plant productivity. At the same time, an increasing number of non-native plants is being recorded in Arctic ecosystems. On Svalbard, 98 alien species have already been identified, especially in disturbed and nutrient enriched soils near settlements.
Previous research has focused on climatic factors as the main cause of Arctic Greening. However, an accelerated rate of soil development (e.g. accumulation of soil C) could also play a key role in shifting vegetation patterns. Thus, variation in the responses of plants to a warmer Arctic may be controlled not only by temperature, but also by an interplay of soil development, the associated soil microbial community, human disturbance and novel plant introductions, as well as the ability of native plants to adapt genetically to these changes. With time, we might therefore see dramatic shifts in the composition of Arctic plant communities, with range-expanding and non-native species outcompeting highly specialized tundra species. Current slow processes due to limited soil development concomitant with restricted plant growth, might accelerate with ongoing warming.
We hypothesize that the modification of environmental conditions, soil properties and biological processes will play a key role in plant community composition, the spread of plant species and their functional variability. To disentangle these different components, we will conduct vegetation surveys, trait measurements and identify soil characteristics on different geologies and elevations on Svalbard. Due to its high variability in surface geology, topography and soil nutrient status in a relatively small spatial scale, Svalbard offers ideal conditions to examine how the interplay between geology, species interactions and soil development might influence Arctic Greening. Furthermore, we will conduct a fully factorial experiment at ETH Zurich, to dissect the effects of plant competition between non-native, range-expanding and native tundra species and the role of different soil characteristics and microbial communities in this context. To assess the ability of native species to respond to the new climate, we will additionally examine the genetic architecture of adaptation and estimate the evolutionary potential of functional traits in the model species Silene acaulis. Here, we present a partial overview of this interdisciplinary project, which began in spring 2022 to help improve our understanding of how sensitive Arctic ecosystems might change in the future.