Mountain ecosystems are disproportionately exposed to global warming, which may put alpine plant species in particular at risk. Plant species' migration and persistence depend on successful seed regeneration, with demographic traits such as germination being strongly sensitive to both present and ancestral climate. Germination may, thus, present a major bottleneck to alpine plant species under climate change, or they may cope through phenotypic plasticity. However, little is known about alpine plant germination under warming, its plasticity, and whether any of these are co‐determined by the climatic origin of the seeds. We investigated intraspecific variation in germination proportion and timing of six co‐occurring alpine plant species from different micro‐ and mesoclimatic origins as response to three temperature treatments using growth chambers. Elevation as well as topographic strata were used as proxies for mesoclimate and mean soil temperature, growing‐ as well as freezing‐degree‐days for microclimate. Our results show that species were plastic in germination proportion and timing in response to temperature, with all species germinating in the warmest treatment. Micro‐ and mesoclimatic origin affected germination traits but did not co‐determine species responses to the temperature treatments. We also demonstrated maternal climatic effects, with seeds from warmer microclimates displaying higher phenotypic plasticity. Furthermore, seeds originating from colder mesoclimates, i.e. the upper elevation range, generally germinated less. Our results suggest that global warming will impact alpine plant regeneration from seeds through concurrent effects during germination, climatic origin as well as shifts in germination timing. Importantly, our results indicate that regeneration from seed may contribute to defining the upper elevational limit of alpine plant species through climatic origin and maternal microclimatic effects.
Cold adapted plant species often dependent on seed dormancy breakage for successful germination, yet the effects of climate-driven changes in soil temperature on this process remain unclear. To improve our understanding of temperature impacts on seed dormancy breakage of Arctic plant species and populations, we investigated how different durations of cold-moist stratification at 0 °C or -5 °C affected seed germination of three Greenlandic plant species: Luzula spicata, Juncus trifidus, and Luzula multiflora. Seeds were collected from natural populations at low (0 m a.s.l) and high (500 m a.s.l.) elevations. Germination patterns differed between species, however, in general germination percentages were significantly higher for low elevational seeds compared to high elevational seeds for all three species. Elevation affected day of first germination only in J. trifidus. Stratification temperature, however, affected both day of first germination for J. trifidus and L. multiflora and the germination rate of L. spicata. Several species-specific interactions among stratification duration, elevation, and stratification temperature were identified. These findings show that Arctic plant species, and even their individual populations, exhibit different dormancy patterns. Climate change may thus affect populations and species differently, with important consequences for future Arctic plant community dynamics.
M. Pagter, Line Holm Andersen, Jakob Deichmann Aagaard et al.· Polar Biology· 0 citations
Investigation of intra-specific phenological variation in Quercus petraea across the French Pyrenees using a multi-environment experimental framework reveals phase-specific differences in phenological responses, with stronger temperature-associated plasticity in spring than in autumn phenology.
Xuewen Zhou, Thomas Caignard, A. Kremer et al.· Plant Physiology· 0 citations
Climate change is accelerating species losses in ecosystems across the world. Seed germination is a critical, climate-dependent phase of the plant life cycle; however, the ecological determinants of germination climate niches within diverse landscapes and across functional types (FTs) are still not well understood. In this study, we characterized seed germination temperature and water availability niches for 28 species that represent different FTs (tree, shrub, grass, forb) and vegetation types (grassy woodland, dry and wet forests) within a temperate bioregion (Sydney, Australia). We tested whether ecological determinants, specifically species’ climate of origin, seed traits, FT and vegetation type explain germination niches and predicted spatial and temporal patterns of germination potential across the landscape under high and low emission scenarios. We found wide variation in thermal and hydric germination niches among species. Optimal germination temperature (thermal niche) was predicted by FT, climate of origin and seed traits, such that shrubs, cool-origin species, and species with large seeds had significantly cooler optimal temperatures for germination. We also quantified spatial and temporal changes in germination potential to identify vulnerable areas and FTs. We found strong species-specific seasonal patterns in germination potential with future climate shifts affecting FTs differently; germination of woody species declined more than forbs. Future germination potential was predicted by historical climatic conditions, with warmer and drier localities being more vulnerable. Overall, our findings demonstrate that species’ germination responses to climate change depend on FT, seed traits, and species climate of origin, with woody species and warmer, drier parts of the landscape emerging as being particularly vulnerable to declines in recruitment. Our study provides a mechanistic understanding of germination responses to temperature and water availability, enabling predictions of vulnerable species and areas for conservation under climate change, and inform large-scale ecosystem restoration approaches through improved species selection and sowing times.
A. A. Alahakoon, Hannah Carle, Caitlin E. Dagg et al.· bioRxiv· 0 citations
Drought-induced tree dieback is impacting forest and woodland ecosystems. One approach to mitigate this is to plant better adapted genotypes of species from warmer and drier climates. This requires understanding drought adaptation both interspecifically and intraspecifically, which we investigated in this common garden experiment. Six genotypes from two related Eucalyptus species, E. microcarpa and E. melliodora, were selected from geographically disjunct locations, five of which encompass the drier ranges of each species. One year old saplings were planted in soil under a rainout shelter. After a five-month adjustment period, irrigation was withheld for 17 weeks to emulate drought, while control trees were irrigated twice weekly. Predawn (Ψpd) and midday (Ψmd) water potentials and stomatal conductance (gs) was measured weekly. Trees were harvested at the end of the drought period, and biomass and leaf osmotic potential were measured. We observed significant differences between species, and only limited evidence for intraspecific variation. Neither species developed substantial water deficits during the drought, but both species exhibited osmotic adjustment. Ψpd and Ψmd were significantly lower and gs was higher in droughted E. microcarpa in comparison to droughted E. melliodora, however the differences were small. Decreases relative to control trees in biomass were greater in E. microcarpa (57%) than E. melliodora (41%). Root:shoot ratios in droughted trees were comparatively greater than well-watered trees in both species, however, dry root weight was greater in E. melliodora across both treatments. Only E. microcarpa had significantly lower SLA (10%) and tree height (26%) in comparison to well-watered trees. Provenances of E. microcarpa from drier regions exhibited less negative Ψpd, less osmotic adjustment and comparatively lower height in droughted vs well-watered trees. Our results highlight the complexity of local drought adaptation and that morphological changes may be as important as physiological trait responses for drought resistance.
Rhys Browning, S. Arndt· Tree Physiology· 0 citations
Sandy ecosystems are inherently fragile, and plant morphological traits are exquisitely sensitive to climatic shifts. We investigated adaptive strategies of three dominant psammophytes (Artemisia scoparia, Cleistogenes squarrosa, and Lespedeza davurica) to simulated warming and precipitation reduction in a 3-year experiment (established September 2019) in the Horqin Sandy Land. Warming and reduced precipitation profoundly reshaped vegetative and reproductive traits. Under reduced precipitation, all species converged by decreasing specific leaf area and specific root length, increasing leaf thickness and roots diameter, while warming elicited species-specific vegetative responses. Reproductive traits exhibited life-form dependence. Warming diminished seed dimensions in L. davurica, yet combined warming and precipitation reduction 60% markedly increased seed dimensions (especially volume) in the herbaceous species A. scoparia and C. squarrosa. All species modestly enlarged pollen axes to mitigate water loss, with herbs showing stronger responses. Precipitation predominantly drove variation in vegetative and pollen traits, while temperature mainly influenced seed and reproductive traits in L. davurica. Plasticity was organ-specific: leaf area, specific root length and seed volume were highly variable (e.g., specific root length in L. davurica, CV = 56.58%), whereas pollen traits remained remarkably stable (CV < 6%). A. scoparia displayed outstanding plasticity among the three psammophytes. Structural equation modeling unveiled that climatic factors exerted the strongest influence on phenotypic plasticity in the annual/biennial A. scoparia. Notably, temperature and moisture indirectly modulated plasticity via direct effects on organ traits, yet driving mechanisms differed for perennials. These findings underscore multi-organ synergy and the critical role of plasticity in psammophytes adaptation.
Wen-Da Huang, Yuanzhong Zhu, Hailun Yu et al.· Journal of Plant Ecology· 0 citations
This review synthesizes current knowledge on the effects of major climate-related factors, including temperature, water availability, and elevated CO 2 , on the physiology, phenology, pollination, and productivity of fruit trees to provide a framework for enhancing the resilience and sustainability of fruit production under changing climatic conditions.
H. Soufi, M. Jabbari, Yazgan Tunç et al.· Biological Research· 0 citations
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