Plant Ecology最新文献

Various anthropogenic activities, e.g. construction, soil disturbance, and introducing artificial plant mixtures on newly-created ski slopes after forest clearing are significant interventions in ecosystems. These drastic acts influence the species composition of vegetation cover in the landscape. Although synanthropic species are typically infrequent in mountainous areas, they tend to flourish in disturbed environments; ski slopes are no exception to this pattern. Here we assessed the composition of vascular plants in three distinct ski slope habitats across 30 Slovak ski resorts: the ski lift entrance areas, the ski lift exit areas, and the central areas of the ski slopes. To gain insights into the dynamics of the spreading of synanthropic species on ski slopes, we used selected species traits, synanthropization indices for both flora and vegetation, and considered specific disturbance criteria. The outcomes of our study confirmed that the highest richness of synanthropic species was observed in plots located at the ski lift entrance areas, while the lowest in the central areas of the ski slopes. This difference could be attributed to the proximity of anthropogenically-disturbed zones, which act as propagule sources for synanthropic species into these mountainous habitats. At the same time, elevation also plays an important role in limiting spread of synanthropic plants on ski slopes. The study of synanthropic plant species distribution on ski slopes provides valuable insights into the complex interactions between human activities and the environment.

In forests, the distribution of vascular epiphytes is controlled by various environmental factors such as host tree size and substrate type. However, a few studies focused on temperate forests, despite the growing interest in temperate forests with high diversity of accidental epiphytes. This study examined the distribution of accidental and obligate epiphytes on 8 Cercidiphyllum japonicum (Cercidiphyllaceae) trees in a Japanese temperate forest based on observations of 1,301 epiphyte individuals belonging to 49 species. As predicted, the number of species and individuals of accidental and obligate epiphytes increased with host tree size. While the percentage of accidental epiphyte species increased with the host tree size, the percentage of obligate epiphyte species decreased; however, these changes were not significant for the number of individuals. Consistent with our hypothesis, the major rooting substrates of accidental and obligate epiphytes was different. Accidental epiphytes primarily depend on arboreal soil and, to a lesser extent, on moss, but are absent on tree bark. Contrastingly, obligate epiphytes were most frequently found on moss, followed by bark and arboreal soil. These results highlight the impact of host tree size on the diversity of accidental epiphytes compared to obligate epiphytes, suggesting that the host tree size effects are different between accidental and obligate epiphytes in temperate forests. Additionally, a thick accumulation of arboreal soil is crucial for the establishment of accidental epiphytes.

Juniperus virginiana is a native species to the eastern United States that typically establishes in old fields and open woodlands. Recently, this species has been encroaching into western U.S. grasslands, altering native plant communities and ecosystem functioning. Across the expanding range of this species, different competitors and soil nutrient content are likely to have contrasting or compounding effects on J. virginiana’s performance, leading to complex establishment patterns. We designed a greenhouse experiment to investigate factors that affect the encroachment of J. virginiana into new habitats that differ in their soil and competitive interactions. We tested the effects of competition with the invasive grass Bromus inermis and native tree Quercus stellata, as well as soil amendment with lime and fertilizer. We measured J. virginiana’s mortality, relative growth rate, biomass, root length, biomass allocation, nitrogen concentration, and midday water potential. Our results suggest that B. inermis negatively affected J. virginiana’s performance and survival. In contrast, Q. stellata did not significantly affect J. virginiana, and the effect of soil amendments was small compared to that of B. inermis. There was a minor interactive effect of lime + fertilizer, implying that J. virginiana tolerates rather than prefers limestone-rich soil. In addition, our results suggest that J. virginiana within the historical range of the Eastern Woodland habitats establishment is likely enhanced by low competition rather than soil nutrient content. In contrast, encroachment into disturbed areas of Western Grasslands should be promoted by the cultivation of J. virginiana but should be inhibited by both abovegsround and belowground competition with grasses.

Mountainous regions typically harbour high plant diversity but are also characterised by low sampling intensity. Coarse-scale species distribution models can provide insights into the distribution of poorly sampled species, but the required bioclimatic data are often limited in these landscapes. In comparison, several environmental factors that vary over relatively fine scales in mountain environments (e.g. measures of topography) can be quantified from remotely-sensed data, and can potentially provide direct and indirect measures of biologically-relevant habitat characteristics in mountains. Therefore, in this study, we combine field-sampled floristic data with environmental predictors derived from remotely-sensed data, to model the ecological niches of 19 montane plant species in the Maloti-Drakensberg mountains, South Africa. The resulting models varied considerably in their performance, and species showed generally inconsistent responses to environmental predictors, with altitude and distance to watershed being most frequently included in models. These results highlight the species-specificity of the forb species’ environmental tolerances and requirements, suggesting that environmental change may result in re-shuffling of community composition, instead of intact communities shifting along gradients. Furthermore, while the relatively high importance of altitude (a proxy for temperature) and topographic wetness index (a proxy for soil moisture) suggest that the flora of this region will be sensitive to shifts in temperature and rainfall patterns, several non-climatic environmental variables were also influential. Our findings indicate that local response to climate change in mountains might be especially constrained by soil type and topographic variables, supporting the important influence of non-climatic factors in microclimatic refugia dynamics.

The Maximum Entropy (MaxEnt) model is widely employed in ecological and geographical studies to predict potential distribution of species with high accuracy. In this research, we applied an optimized MaxEnt model to forecast the historical, current, and future distribution trends of Rhus chinensis. Our study elucidated the dynamics of species distribution shifts and pinpointed key environmental drivers. The analysis indicated that the min temperature of coldest month, temperature annual range, annual precipitation, and slope predominantly influence the distribution of R. chinensis in the current period. Notably, the most suitable habitat areas for R. chinensis exhibited significant variations across different time periods. During the Mid Holocene, as climate change, the extent of potential suitable habitats expanded markedly relative to the Last Glacial Maximum, showcasing distinct geographical distribution shifts. Under various future climate scenarios, the area deemed suitable for R. chinensis is expected to expand, with the total areas of high suitability increasing more under high-emission scenarios than under low-emission scenarios. The model also identified small, highly suitable areas in Motuo and Chayu in southern Xizang, suggesting new opportunities for the collection and cultivation of R. chinensis. These predictions support efforts to strengthen the conservation of existing resources and promote the sustainable utilization of China’s medicinal plant resources.

Invasive plants disrupt ecosystems by influencing species interactions, aiding co-invader integration, and worsening competition for native plants. Successful forest invasive species management relies on grasping these interaction patterns at the community level. This study aims to assess the community attributes of invasive plants in tropical forests of Northeast India, examining their dominance in various habitats, elucidating their influence at the community level and some species-specific effects on associated co-invaders and non-invasive groups. The present investigation recorded 101 invasive plant species mostly of neotropical origin, comprising of grasses, sedges, forbs, shrubs, trees, and vines. The findings revealed both positive and negative effects of invasive species richness and their percentage at community level and throughout different habitats. However, the presence of dominant invasive species caused a substantial decrease in species diversity of plant community in the study area, depicting a significant negative association with the non-invasive group and a notable positive association with the co-invasive group. These findings offer valuable insights by specifying the community-level impacts of exotic invaders on the natural plant population which will be very helpful in devising effective management plans to counter biotic invasion in the biodiversity rich tropical forested landscapes.

Specific leaf area (SLA) plays a critical role in carbon assimilation and nutrient cycling. While leaf habit (deciduous vs. evergreen) has often been recognized as a reliable predictor of SLA—with deciduous species typically having higher mean SLA values due to lower concentration of structural components compared to evergreens—high variation in SLA among evergreen species suggests further investigation of variation for species with this leaf habit could improve predictions of SLA effects on community and ecosystem processes. Furthermore, the presence of leaves of different ages in evergreen plants, emerging over multiple years, could amplify the within-individual variation in SLA, which remains underexplored. Here we report variations of SLA measured from c. 2000 leaves collected from 36 individuals across 19 woody species in an understory environment in New Zealand (NZ). We found that while most deciduous species, predominantly non-native, clustered towards higher SLA values, evergreen species presented a wide SLA spectrum. Moreover, we found that while being deciduous, having a smaller leaf size, and younger leaves, collected from lateral branches, correlated with elevated SLA values, the leaf habit did not primarily drive the within-individual SLA variation. Instead, smaller leaf size emerged as a significant predictor of within-individual SLA variation. The branch-order effect on SLA underscores a methodological consideration: accurate estimation of total leaf area in evergreen trees requires representative sampling across all branch orders. Our study also highlights the need for integrating leaf traits such as leaf size and branch order into functional trait analyses. Further research is vital to understand the underlying mechanisms of these trait variations and their impacts on ecosystem functioning.

Woody plant encroachment is influenced by interactions between the physical environment and vegetation, which create heterogenous microenvironments some of which favor shrub recruitment through mitigation of the abiotic environment. Encroachment of native shrub, Morella cerifera into grasslands on Hog Island, Virginia has been attributed to warmer winter temperature; however, recruitment of seedlings in grasslands may be impacted by multiple factors at the level of the microhabitat. Our study focuses on a critical gap in understanding factors specifically influencing M. cerifera seedling recruitment and survival. By experimentally planting M. cerifera seedlings at varying dune elevations and grass densities, we tested hypotheses that dune elevation influences the microclimate, soil characteristics and vegetation cover and that grass cover/density is related to shrub establishment. We tested these hypotheses through gathering data from temperature data loggers, conducting soil water content and chloride analyses, and determining percent cover of grasses relative to dune elevation. Results indicate that dune elevation was positively related to moderated temperatures with reduced temperature extremes and vegetation cover/composition that led to favorable locations for M. cerifera establishment and growth. Where dune elevation is > 2 m, we document an upper limit of grass cover on natural seedling establishment, suggesting a switch from facilitative to competitive effects with grass density. Overall, our work demonstrates interactions between dune elevation and medium grass density has a facilitative influence on M. cerifera establishment and can be used for future predictions of shrub growth with rising sea-levels.

Nutrients contained in plant tissues serve as the driving force behind plant and herbivore interactions. The nutrient level, including different kinds of elements and amount of fertilizer, can vary owing to variations in soil composition and this can directly impact plant defense response against herbivores. Plants take up nutrients via two pathways: (i) directly through the root hairs and epidermis and (ii) indirectly through the beneficial microbes that interact with plant roots, such as mycorrhizal fungi and rhizobacteria. The associated microbes, modifying plant nutrient composition, can indirectly affect plant and herbivore interactions. These direct and indirect nutrient uptake pathways adjust plant resistance or tolerance to herbivore attack, as evidenced by factors such as herbivore performance, plant nutrient status, biomass allocation, and compensatory growth. In turn, aboveground and belowground herbivory can exert an effect on nutrient exchange between plants and their associated microbes, primarily on the key resources such as carbon (C), nitrogen (N) and phosphorus (P). Furthermore, it shows that herbivory, in the presence of plant associated beneficial microbes, has no negative effect on plant N and C content. The molecular mechanisms underlying these ecological interactions are being systematically uncovered. In order to outline the research progress in this field, this review synthesizes the current scientific literature regarding the mutual effect of nutrients on plant–herbivore interactions. It aims to support efforts in maintaining the sustainability of ecosystem by optimizing plant defense strategies via managing nutrient variability.