Variation of plant communities along an elevation gradient in the Guandi Mountains, North China

2004 ◽  
Vol 5 (2) ◽  
pp. 227-233 ◽  
Author(s):  
J.T. Zhang ◽  
T.G. Chen
Keyword(s):  
Plant Communities ◽  
North China ◽  
Elevation Gradient

Multiple stabilizing pathways in wetland plant communities subjected to an elevation gradient

2019 ◽  
Vol 104 ◽  
pp. 704-710 ◽  
Author(s):  
Hui Fu ◽  
Guixiang Yuan ◽  
Erik Jeppesen ◽  
Dabing Ge ◽  
Dongsheng Zou ◽  
...  
Keyword(s):  
Plant Communities ◽  
Elevation Gradient ◽  
Wetland Plant ◽  
Wetland Plant Communities

scholarly journals Palustrine forested wetland vegetation communities change across an elevation gradient, Washington State, USA

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8903
Author(s):  
Nate Hough-Snee
Keyword(s):  
Plant Species ◽  
Plant Communities ◽  
Indicator Species ◽  
Elevation Gradient ◽  
Forested Wetlands ◽  
Wetland Vegetation ◽  
Forested Wetland ◽  
Wetland Plant ◽  
Wetland Plant Communities ◽  
Understory Plant

Background Forested wetlands support distinct vegetation and hydrology relative to upland forests and shrub-dominated or open water wetlands. Although forested wetland plant communities comprise unique habitats, these ecosystems’ community structure is not well documented in the U.S. Pacific Northwest. Here I surveyed forested wetland vegetation to identify changes in community composition and structure across an elevation gradient that corresponds to flooding stress, asking: (1) How do forested wetland plant communities change across an elevation gradient that corresponds to flood frequency and duration? (2) At what relative elevations do different plant species occur within a wetland? Methods I measured overstory tree basal area and structure and understory vascular plant composition in three zones: wetland buffers (WB) adjacent to the wetland, an upper wetland (UW) extent, and a lower wetland (LW) extent, surveying individual trees’ root collar elevation relative to the wetland ordinary high-water mark (OHWM). I estimated understory plant species abundance in sub-plots and surveyed these plots’ height above the OHWM. I used non-metric multidimensional scaling ordination to identify patterns in vegetation communities relative to wetland elevation, and tested for compositional differences between the WB, UW and LW zones using PERMANOVA. I calculated overstory and understory indicator species for each wetland zone using indicator species analysis. Results Forest overstory composition changed across the elevation gradient, with broad-leaved trees occupying a distinct hydrologic niche in low-lying areas close to the OHWM. Conifer species occurred higher above the OHWM on drier microsites. Pseudotsuga menziesii (mean elevation = 0.881 m) and Tsuga heterophylla (mean elevation = 1.737 m) were overstory indicator species of the WB, while Fraxinus latifolia (mean elevation = 0.005 m) was an overstory indicator for the upper and lower wetland. Understory vegetation differed between zones and lower zones’ indicator species were generally hydrophytic species with adaptations that allow them to tolerate flooding stress at lower elevations. Average elevations above the OHWM are reported for 19 overstory trees and 61 understory plant species. By quantifying forested wetland plant species’ affinities for different habitats across an inundation gradient, this study illustrates how rarely flooded, forested WB vegetation differs from frequently flooded, LW vegetation. Because common management applications, like restoring forested wetlands and managing wetland responses to forest harvest, are both predicated upon understanding how vegetation relates to hydrology, these data on where different species might establish and persist along an inundation gradient may be useful in planning for anticipated forested wetland responses to restoration and disturbance.

scholarly journals Indaziflam controls non-native annual mustards but negatively affects native forbs in sagebrush steppe

2021 ◽  
pp. 1-28
Author(s):  
Jordan Meyer-Morey ◽  
Matthew Lavin ◽  
Jane Mangold ◽  
Catherine Zabinski ◽  
Lisa J. Rew
Keyword(s):  
Plant Community ◽  
Plant Communities ◽  
Seed Bank ◽  
Soil Seed Bank ◽  
Elevation Gradient ◽  
Late Summer ◽  
Ex Situ ◽  
Sagebrush Steppe ◽  
Native Plant ◽  
Forage Production

Abstract Non-native plant invasions can have devastating effects on native plant communities; conversely management efforts can have non-target and deleterious impacts on desirable plants. In the arid sagebrush steppe rangelands of the western United States, non-native winter annual species affect forage production and biodiversity. One method proposed to control these species is to suppress the soil seed bank using the pre-emergent herbicide indaziflam. Our goal was to evaluate the efficacy of indaziflam to control non-native annual mustards (Alyssum spp.) and to understand potential non-target effects of management on the diverse mountain sagebrush steppe plant communities within Yellowstone National Park. Six sites were established along an elevation gradient (1615 – 2437m), each with high and low Alyssum spp. infestations. We applied 63g ai ha−1 of indaziflam in late summer of 2018 and evaluated plant community cover in situ for two years after treatment, and emergence of forb species from the soil seed bank ex situ. Indaziflam was highly effective at controlling Alyssum spp. emergence for two years. Richness and Shannon’s diversity of the non-target plant community were significantly lower in sprayed plots than the control, and both decreased along the elevation gradient. These reductions were due to a decrease in perennial forbs and native annual forbs in the sprayed plots; perennial graminoids were not affected. Overall, the above ground and seed bank community composition was negatively impacted by indaziflam, and these effects were strongest for the native annual forbs that rely on annual regeneration from the seed bank. The effects of this herbicide to the non-target community should be evaluated beyond the length of our study time, however we conclude indaziflam should likely be reserved for use in areas that are severely invaded and have seed banks that are comprised of non-desirable species rather than diverse, native mountain sagebrush communities.

scholarly journals Different temporal trends in vascular plant and bryophytes communities along elevational gradients over four decades of warming

2020 ◽  
Author(s):  
Antoine Becker-Scarpitta ◽  
Diane Auberson-Lavoie ◽  
Mark Vellend
Keyword(s):  
Plant Communities ◽  
Vascular Plants ◽  
Environmental Changes ◽  
Vascular Plant ◽  
Elevation Gradient ◽  
Temporal Trends ◽  
Community Change ◽  
Ecosystem Functions ◽  
Ecological Communities

Abstract1: Despite many studies showing biodiversity responses to warming, the generality of such responses across taxa remains unclear. Very few studies have tested for evidence of bryophyte community responses to warming, despite the fact that bryophytes are major contributors to diversity in many ecosystems, playing a central role in ecosystem functions. Understanding variation among taxa in their responses to warming is crucial for identifying priorities in conservation.2: We report an empirical study comparing long-term change of bryophyte and vascular plant communities in two sites with contrasting long-term warming trends. To assess long-term responses of ecological communities to warming, we used “legacy” botanical records as a baseline for comparison with contemporary resurveys.We hypothesized that ecological changes would be greater in sites with a stronger warming trends, and that vascular plant communities would be more sensitive than bryophyte communities to climate warming. For each taxon in each site, we quantified the magnitude of changes in species’ distributions along the elevation gradient, species richness, and community composition.3: Temporal changes in vascular plant communities were consistent with the warming hypothesis, but this was not the case for bryophytes. We also did not find clear support for the hypothesis that vascular plants would show greater sensitivity than bryophytes to warming, with results depending on the metric of community change. As predicted for sites with a strong warming trend, we found a significant upward shift in the distributions of vascular plants but not bryophytes.Synthesis: Our results are in accordance with recent literature showing that local diversity can remain unchanged despite strong changes in composition. Regardless of whether one taxon is systematically more or less sensitive to environmental change than another, our results suggest that vascular plants cannot be used as a surrogate for bryophytes in terms of predicting the nature and magnitude of responses to warming. In sites that experienced the same environmental changes, we found that communities of bryophytes and vascular plants did not predictably change in the same ways. Thus, to assess overall biodiversity responses to global change, data from different taxonomical groups and community properties need to be synthesized.

scholarly journals Direct and indirect effects of land-use intensity on plant communities across elevation in semi-natural grasslands

2020 ◽  
Author(s):  
Oksana Y. Buzhdygan ◽  
Britta Tietjen ◽  
Svitlana S. Rudenko ◽  
Volodymyr A. Nikorych ◽  
Jana S. Petermann
Keyword(s):  
Land Use ◽  
Plant Communities ◽  
Indirect Effects ◽  
Elevation Gradient ◽  
Grazing Intensity ◽  
Bare Soil ◽  
Direct And Indirect Effects ◽  
Natural Grasslands ◽  
Soil Exposure ◽  
Effects Of Land Use

AbstractGrassland biodiversity is among the most vulnerable to land use. How to best manage semi-natural grasslands for maintaining biodiversity is still unclear in many cases because processes may depend on environmental conditions and indirect effects are rarely considered. Here we evaluate the relative importance of direct and indirect effects of grazing intensity on plant communities along an elevational gradient on a large topographic scale in the Eastern Carpathians in Ukraine. We sampled 31 semi-natural grasslands exposed to cattle grazing in two years. Within each grassland site we measured plant community properties such as the number of species, functional groups, and the proportion of undesirable weeds. In addition, we recorded cattle density (as proxy for grazing intensity), soil properties (bare soil exposure, soil organic carbon, and soil pH) and densities of soil decomposers (earthworms and soil microorganisms). We used structural equation modelling to explore direct and indirect effects of grazing intensity on plant communities along the elevation gradient. We found that cattle density decreased plant species and functional diversity but increased the proportion of undesirable weeds. Some of these effects were directly linked to grazing intensity (i.e., species richness), while others (i.e., functional diversity and proportion of undesirable weeds) were mediated via bare soil exposure. Although grazing intensity decreased with elevation, the effects of grazing on the plant community did not change along the elevation gradient. Generally, elevation had a strong positive direct effect on plant species richness as well as a negative indirect effect, mediated via altered soil acidity and decreased decomposer density. Our results indicate that plant diversity and composition are controlled by the complex interplay among grazing intensity and changing environmental conditions along elevation. Furthermore, we found lower soil pH, organic carbon and decomposer density with elevation, indicating that the effects of grazing on soil and related ecosystem functions and services in semi-natural grasslands may be more pronounced with elevation. This demonstrates that we need to account for environmental gradients when attempting to generalize effects of land-use intensity on biodiversity.

scholarly journals Impact of natural factors on population changes of herbaceous plants species and assessment of their state in present high-mountain conditions of the Ukrainian Carpathians

2021 ◽  
Vol 15 (1) ◽  
pp. 67-78
Author(s):  
R. Dmytrakh ◽  
Keyword(s):  
Plant Species ◽  
Plant Communities ◽  
Environmental Conditions ◽  
Elevation Gradient ◽  
Spatial Differentiation ◽  
Herbaceous Plants ◽  
High Mountain ◽  
Herbaceous Plant ◽  
Mountain Zone ◽  
Regenerative Ability

Background. Natural ecosystems of the Ukrainian Carpathians have been signi­ficantly transformed during the last few years due to the impact of climate factors and an increased activity of nature restoration processes. The study of the influence of the external environ­mental factors on populations of the herbaceous plant species is particularly topical for the high-mountain ecosystems. As a result of gradual restoration of native plants, specific changes occur in the structural and spatial organization of populations of many herbaceous plant species. Thus, considering the increased climate changes and regenera­tive activity, the assessment of the present condition of the populations of herbaceous plant species, their regenerative ability, response to changing environmental conditions and individual peculiarities of performance in the altered environmental conditions are important. Methods. The conventional stationary and route-field methods were applied in order to determine changes in the structural organization of high-mountain plant populations and their regenerative ability. The initial diagnostic parameters of the populations’ condition include the individual growth peculiarities and the nature of dynamic trends under the changed environmental conditions. During the ontogenetic development of plants, the most important changes occur within the generative phase that ensures the rege­nera­tion and self-maintenance of populations by means of seeds; those changes are a significant indicative feature. The long-term observations of different types of plant communities were applied; these included the records of the main parameters and characteristic features at permanent test sites. The transects are located in the alpine, subalpine and upper forest belts of the Ukrainian Carpathians within 1000–2000 m a.s.l. altitudinal range. The study comprises such behavioral features of the species populations as phenological (intensity phenophase, flowering rhythmics), demographic (number of individuals, spatial differentiation), reproductive (generative reproduction, seed productivity), etc., which enable the determination of their adaptation and ability to exist under the changed environmental conditions. Results. The continuous monitoring of different high-mountain plant aggregations showed that in some cases the number of species which are distinguished by active regenerative strategy aimed at further extension of the habitat is growing, while in other cases the species demonstrated the opposite trend resulting from their inability to adapt to changing habitat conditions. It has been determined that the vegetative development of the populations of high-mountain plant species is closely related to temperature conditions which influence phenology, dynamics of the numbers of individuals and the nature of their reproduction. A significant influence of warming on the processes of seasonal development of populations and flowering abundance is evidenced by their increased number and migration to much higher hypsometric levels of the high-mountain zone. The increased ability to generative reproduction contributes to the dissemination of seeds and formation of new population loci Valeriana simplicifolia, V. transsilvanica, Silene dioica, Astrantia major, Doronicum carpaticum, Euphorbia carniolica, etc. in favourable micro-habitats at significantly higher hypsometric levels of the high-mountain zone (1600–2000 m a.s.l.). Another natural factor of changes in populations of herbaceous plant species is the impact of restoration succesions in different types of plant communities. These changes are usually accompanied by increased shading and crowding of vegetation due to the spread of more competitive tree and shrub species as well as adventive species of tall herbaceous plants. It refers mostly to grassland species that need open sites for the effective population recruitment. Radical changes can be observed in the structural organization of the populations of herbaceous plants species due to an increased cenotic activity of more competitive species. Such changes reduce the regenerative ability of the populations of herbaceous plants species and trigger their fragmentation. Thus, the change of ecological and cenotic conditions of various plant communities along the elevation gradient of the highlands predetermines different charac­teristic features of the populations of herbaceous plant species and their unequal spatial differentiation. Conclusions. It has been determined that present natural processes occurring in the populations of herbaceous plant species of the high-mountain zone controversially influence their regenerative ability and the nature of changes in their structural organization. The dynamics of populations in each separate case is defined by the influence of natural and climate changes and their association with particular plant communities along the elevation gradient of the high-mountain zone. The multi-year dynamics of the numbers of generative individuals represents their regenerative ability in populations and dependence on weather conditions. The important feature of active regeneration of the populations is the development of their local foci in favorable microhabitats at significantly higher hypsometric levels of the high-mountain zone, in particular, the alpine and the upper margin of the alpine. Occurrence of new populations loci is indicative of their ability to reproduce and survive. In some cases, the dynamic trends in populations are accompanied by an increased number of individuals and extension of their habitats, while in other cases, trends are the opposite, which is caused by a decreased number of individuals and their degradation. The processes which are observed during the regeneration of species populations are related to their ascending extension to various hypsometric levels, as well as the strengthening of the positions of the populations of tree and shrub layer species and adventive representatives of tall herbaceous plants which are peculiar to lower layers. Significant overgrowth processes, which result in gradual exclusion of herbaceous plant species typical of meadow communities aggregations, are observed in the habitats of the populations of many types of herbaceous plants and at the upper margin of the forest and subalpine layers. Thus, the changes in ecological and cenotic conditions of various plant communities along the elevation gradient of the highlands predetermines different characteristic features of the populations of herbaceous plant species and their unequal spatial differentiation.

scholarly journals Complex Changes in Plant Communities across a Subarctic Alpine Tree Line in Labrador, Canada + Supplementary Appendix Table (See Article Tools)

ARCTIC ◽  
2015 ◽  
Vol 68 (4) ◽  
pp. 500 ◽  
Author(s):  
Andrew J. Trant ◽  
Keith Lewis ◽  
Brittany H. Cranston ◽  
Julia A. Wheeler ◽  
Ryan G. Jameson ◽  
...  
Keyword(s):  
Plant Communities ◽  
Species Turnover ◽  
Abiotic Factors ◽  
Elevation Gradient ◽  
Alpine Tundra ◽  
Tree Cover ◽  
Tree Line ◽  
Forest Tundra ◽  
Abrupt Changes ◽  
Species Establishment

As climate warms, abiotic factors, as well as plant community and biodiversity structure, may constrain or promote the movement of ecotone boundaries. Our study sought to examine how plant communities change across the tree-line ecotone of the Mealy Mountains in Labrador, Canada. We established eight transects (50–100 m in length) along an elevation gradient in three tree-line zones (forest, forest-tundra, and alpine-tundra) and recorded all species and cover of vegetation in contiguous 1 × 1 m quadrats. Companion abiotic parameters of nutrients and soil temperature were also measured. The absence of abrupt changes in important soil nutrients and growing season temperatures suggests that these factors do not limit tree species establishment beyond the current tree line. Vegetation cover and richness, however, were highly variable and in some cases changed non-linearly across the tree-line ecotone. Tree cover and species density generally decreased with elevation, while some field layer species (< 25 cm in height) increased; the latter change seems to be influenced by ground shrubs rather than herbaceous species. As expected, transects separated by the greatest difference in elevation were the least similar (higher beta diversity/species turnover); however, species turnover between the forest and forest-tundra transects was higher than it was between forest-tundra and alpine-tundra transects, even though the latter were separated by a greater elevation. Community structure and species turnover vary greatly across a tree line with the greatest differences between the forest and the forest-tundra, suggesting a biotic or abiotic barrier. While our ability to predict how the tree line will respond to continued climate change is complicated by these patterns in plant communities, the potential barriers investigated and others identified will be a useful focus for future studies.

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