Vascular Plant Richness Research Articles

Deer exclusion unveils abiotic filtering in forest understorey plant assemblages.

The role of deer (family Cervidae) in ecosystem functioning has traditionally been neglected by forest ecologists due to the animal's scarcity in most parts of the northern hemisphere. However, the dramatic rebound in deer populations throughout the 20th century has brought deer browsing to the forefront of forest ecological questioning. Today there is ample evidence that deer affect tree regeneration, understorey plant and animal diversity, and even litter decomposition. However, the mechanisms underlying the effects of deer on forest ecosystems remain unclear. Among others, the relative role of abiotic factors versus biotic interactions (e.g. herbivory) in shaping plant assemblages remains largely unknown. We used a large-scale experiment with exclosures distributed along abiotic gradients to understand the role of black-tailed deer (Odocoileus hemionus sitchensis) on the forest understorey on the Haida Gwaii archipelago (western Canada), a unique context where most of the key ecological effects of deer presence have already been intensively studied. Our results demonstrate that 20 years of deer exclusion resulted in a clear increase in vascular plant richness, diversity and cover, and caused a decline in bryophyte cover. Exclusion also unveiled abiotic (i.e. soil water availability and fertility) filtering of plant assemblages that would otherwise have been masked by the impact of abundant deer populations. However, deer exclusion did not lead to an increase in beta diversity, probably because some remnant species had a competitive advantage to regrow after decades of over browsing. We demonstrated that long-term herbivory by deer can be a dominant factor structuring understorey plant communities that overwhelms abiotic factors. However, while exclosures prove useful to assess the overall effects of large herbivores, the results from our studies at broader scales on the Haida Gwaii archipelago suggest that exclosure experiments should be used cautiously when inferring the mechanisms at work.

Restoration of montane heathlands – Early- and mid-successional stages promote phytodiversity

Heathlands are highly threatened ecosystems with high conservation value. Montane heathlands have suffered from widespread habitat loss due to land-use abandonment and afforestation. The aim of our study was to analyse the long-term effects of montane heathland restoration, nine to ten years after restoration, on vegetation in the Rothaar Mountains (Central Germany). We compared vegetation composition in four vegetation types: (i) early-successional heathland stages on sod cut sites or ski pistes (hereafter referred to as EARLY), (ii) late-successional (old-growth) heathland stages (LATE), (iii) restored heathlands on former spruce forests where seed transfer by hydroseeding or the application of chopper material (crushed aboveground biomass from donor heathland site including seeds) had been applied (RESTORED) and (iv) windthrows with salvage logging (WIND). In every vegetation type, ten vegetation relevés were carried out and the cover of all vascular plant, bryophyte and terricolous lichen species were analysed. Furthermore, soil samples were taken in every relevé and measured with respect to soil acidity as well as carbon, nitrogen, phosphate and potassium contents.Our study demonstrated that the restoration plots were characterised by chemical soil conditions comparable to those of existing heathland communities. RESTORED was the hotspot of phytodiversity. Species richness of vascular plants, threatened vascular plants and target species peaked on RESTORED, followed by EARLY. Additionally, EARLY was characterised by the highest number of terricolous lichen species and threatened bryophyte species.The applied restoration measures were successful in establishing montane-heathland and acidic-grassland vegetation on former spruce forests. However, two usually dominant species of montane heathlands, Vaccinium myrtillus and Vaccinium vitis-idaea, had hardly established. Both species are slow colonisers and require specific microsites characterised by high moisture and organic content of the soil for generative reproduction. Additionally, the study demonstrated that early- to mid-successional stages of montane heathlands play a vital role for the conservation of cryptogams and low-competitive plant species.

Restoration strategies in boreal forests: Differing field and ground layer response to ecological restoration by burning and gap cutting

The boreal biome is one of the largest in the world and its forests have been widely exploited for centuries. Consequently, large areas have suffered ecological simplification and loss of biodiversity. Under the current circumstances passive conservation measures are no longer enough and active restoration techniques need to be developed and assessed to preserve and recover the loss of biodiversity. We evaluated short- and long-term effects of two restoration methods aimed at mimicking natural disturbances on species richness, Shannon Diversity and community composition of vascular plants in the field layer and bryophytes in the ground layer. The experiment consisted of 18 forest stands in northern Sweden; each assigned to a different treatment: prescribed burning, gap cutting and untreated stands left as controls. A before-after control-impact (BACI) study design was applied and data was collected on three occasions: once prior to restoration (2010) and twice post restoration; one year (2012) and eight years after (2019). We analysed the differences in species richness and Shannon Diversity with linear mixed effect models and community composition changes with multivariate methods. Fire treatment caused an initial decline in diversity for both field and ground layer, but in the long-term, field layer surpassed the species richness and Shannon Diversity values found prior to restoration. Ground layer bryophytes species richness and Shannon Diversity remained lower than pre-treatment. Prescribed burning should, therefore, be used with caution in core areas for bryophyte diversity. Community composition in burned stands differed significantly between each time point as well as when compared to other treatments, for both layers. By contrast, we found no significant differences in diversity measures or community composition after gap cutting. The absence of effects from gap cutting suggests that minor changes in canopy cover does not affect the vegetation structure of forest stands. The organism group-specific responses, and temporal variability to restoration, highlight the importance of including more than one organism group, different restoration methodologies, and long-term studies in order to properly assess restoration outcomes at landscape level.

Bryophyte Diversity along an Elevational Gradient on Pico Island (Azores, Portugal)

The study of elevational patterns is a valuable method for inferring the influence of the climate and other variables in the regional distributions of species. Bryophytes are ideal for revealing different environmental patterns in elevational studies, since they occur from sea level to above the tree line. Taking advantage of the long elevational transect of Pico Island and the use of standardized survey methods, our main aims were: (1) to identify and characterize the alpha and beta diversities of bryophytes across the full elevational gradient (12 sites of native vegetation, ranging from 10 to 2200 m above sea level [a.s.l.]); (2) to detect the ecological factors driving bryophyte composition; (3) to identify bryophytes’ substrate specificity; and (4) to check the presence of rare and endemic species. The identification of 878 microplots yielded 141 species (71 liverworts and 70 mosses), almost half of those known to occur on Pico Island. The bryophyte species richness followed a parabolic unimodal pattern with a mid-elevation peak, where the richest native forests occur. A canonical correspondence analysis (CCA) of the bryophyte composition and explanatory variables revealed the effect of the elevation, precipitation, disturbance, richness of vascular plants and bark pH in explaining bryophyte compositions at regional levels. Very few species of bryophytes showed substrate specificity. Pico Island’s elevational gradient could be an asset for studying long-term changes in bryophyte species composition and alpha diversity under global change.

Impacts of rock climbing on cliff vegetation: A methods review and best practices

AbstractQuestionsCliff vegetation is diverse, understudied, and threatened by increased human disturbance. The growing popularity of rock climbing heightens the need for science‐based management to balance recreational use and conservation of cliff ecosystems. What has existing research revealed about the impact of climbing on vegetation? Are the conclusions consistent across the literature? If not, how can research methods be streamlined and standardized to produce more consistent results and reliable conclusions?MethodsWe present a review of vegetation‐focused climbing‐impact studies written in English. We compare study design and climbing‐specific considerations in 19 studies and report the impact of rock climbing on richness and abundance of lichens, bryophytes, and vascular plants. We then propose a set of best practices to guide design of future studies.ResultsOur work reveals that existing studies have employed widely differing methods for data collection and analysis. The effects of climbing on vegetation also varied among studies. Standardizing methods, such as pairing climbed and unclimbed transects or including a metric for climbing use, will generate more reliable and useful conclusions about the effect of climbing on vegetation.ConclusionsClimbing will increasingly disturb cliff ecosystems. Our proposed best practices for climbing study methods are one way to produce more accurate information to inform climbing management plans, ultimately enhancing cliff conservation.

Precipitation declines influence the understory patterns in Nothofagus pumilio old-growth forests in northwestern Patagonia

Forest understories are essential to plant diversity and ecosystem functioning. However, studies about changes in understory patterns as affected by varying precipitation are scarce. Pure Nothofagus pumilio (common name: lenga) forests dominate the eastern side of the Andes mountains in Patagonia across an ample range of precipitation (~1500–500 mm). By studying the same forest type, in the same developmental stage (old-growth), we aimed to isolate the effects of precipitation upon these N. pumilio ecosystems, particularly for the understory. Three sites were selected with annual average precipitations of ~1000 mm (humid), ~800 mm (mesic), and 600 mm (dry), with a distance of 30 km between the humid and the dry sites, and only 18 km between the mesic and the dry sites. In each site, we established three 40 × 40 m plots in 4 blocks, and 30 1 m2 regeneration subplots within each plot. In each subplot we measured vascular plant cover, richness and diversity (alpha and beta), litter cover and coarse woody debris, plus several abiotic variables. We analyzed the data with mixed analysis of variance, differences of understory plant communities through blocked distance-based multivariate analysis of variance, and visualized the groups (sites) with non-metric multidimensional scaling. Indicator species at each site were identified through blocked species indicator analysis. The dry site differed significantly compared to the humid and mesic sites, with the lowest understory cover (4 vs. 82–78%), plant richness (15 vs. 25–26 species), and Simpson diversity index (0.05 vs. 0.66–0.64) . Beta turnover diversity was higher between the dry site with either the humid and the mesic sites (βt = 0.613 and 0.561, respectively), which in turn had more species in common (βt = 0.115). An increase in exposed mineral soil, soil water content, and leaf area index occurred from dry to humid sites, and vice versa for transmitted radiation and litter cover. All sites had different indicator species, but with indicator values increasing from dry to humid sites. The dramatic impoverishment of the plant community once precipitation drops within the range of 800 and 600 mm per year in Northern Patagonia sets a warning to the potential effects of climate change upon N. pumilio-dominated forest ecosystems and their plant diversity. Some forest management and potential adaptation strategies are proposed.

How sensitive are epiphytic and epixylic cryptogams as indicators of forest naturalness? Testing bryophyte and lichen predictive power in stands under different management regimes in the Białowieża forest

The aim of this study was to test the sensitivity of epiphytic and epixylic bryophytes and lichens as indicators of forest naturalness, by comparing their diversity patterns with forest structural, compositional and historical features associated with different management/protection regimes and protection time spans. The study was carried out in the Białowieża Forest (Poland). Out of 1370 pre-existing inventory plots established all across the Polish part of the Białowieża Forest, we randomly selected 10 plots for each of the 18 plot aggregation groups resulting from the combination of 3 management/protection regimes and 6 habitat types, for an overall number of 180 plots. At each of them, we carried out bryophyte and lichen sampling on four substrates (coarse woody debris – CWD, standing dead trees, stumps, living trees). The management/protection regimes exemplifying the gradient of forest naturalness were: the 100 years-old Białowieża National Park (BNP), a set of more recently established nature reserves and managed forests. We tested differences in mean species richness values among management/protection regimes, protection time spans, habitat types and stand age classes by analysis of variance and calculated coefficients of correlation with 45 selected structural and compositional features of forest stands. Differences in species composition of epiphytic and epixilic bryophytes and lichens among management/protection regimes were tested by ordination methods. Lastly, we compared frequency of red-listed species and primeval forest relics among management/protection regimes. Species richness of lichens was significantly correlated with the degree of forest naturalness assessed by structural and historical features along the naturalness gradient, with the highest number of species recorded in BNP and the lower in managed stands, while bryophyte number did not exhibit a clear dependence on the management regimes. Relic species of primeval forests and red-listed species occurred with significantly higher frequency in protected areas than in managed forests for both lichens and bryophytes, with the highest frequency observed in BNP for lichens and in nature reserves for bryophytes. Volume of deadwood, particularly of CWD in advanced decays stage, species richness of undergrowth vascular plants, tree layer diversity, shrub cover and herb layer cover exhibited the strongest correlation with cryptogam species richness and cover on the various substrates. Response to light availability strongly differenciated bryophyte and lichens optimal niches. The results of this study clearly show that cryptogams, and lichens in particular, are indeed reliable ecological indicators of forest status, since they sensibly intercepted the environmental changes observable along the tested naturalness gradient.

Multi-taxon conservation in northern forest hot-spots: the role of forest characteristics and spatial scales

ContextBiodiversity is highly affected by industrial forestry, which leads to the loss and fragmentation of natural habitats. To date, most conservation studies have evaluated associations among a single species group, forest type, or spatial scale.ObjectiveThe objective was to evaluate the richness of multiple species groups across various forest types and characteristics at multiple scales.MethodsWe used the occurrence data for 277 species of conservation interest from 455 stands of high conservation value, including four species groups and four forest types.ResultsLocal, landscape, and regional forest characteristics influenced biodiversity in a non-uniform pattern among species groups and forest types. For example, an increased local spruce basal area in spruce forests was associated with higher vascular plant and bryophyte richness values, whereas macrofungi and lichen richness were positively correlated with deadwood availability, but negatively correlated with the spruce volume in the landscape. Furthermore, landscapes with twice as much mature forest as the average, had more than 50% higher richness values for vascular plants, macrofungi, and lichens.ConclusionAmong sessile species groups in northern forests, a uniform conservation strategy across forest types and scales is suboptimal. A multi-faceted strategy that acknowledges differences among species groups and forest types with tailored measures to promote richness is likely to be more successful. Nevertheless, the single most common measure associated with high richness across the species groups and forest types was mature forest in the landscape, which suggests that increasing old forests in the landscape is a beneficial conservation strategy.

Altitudinal Vascular Plant Richness and Climate Change in the Alpine Zone of the Lefka Ori, Crete

High mountain zones in the Mediterranean area are considered more vulnerable in comparison to lower altitudes zones. Lefka Ori massif, a global biodiversity hotspot on the island of Crete is part of the Global Observation Research Initiative in Alpine Environments (GLORIA) monitoring network. The paper examines species and vegetation changes with respect to climate and altitude over a seven-year period (2001–2008) at a range of spatial scales (10 m Summit Area Section-SAS, 5 m SAS, 1 m2) using the GLORIA protocol in a re-survey of four mountain summits (1664 m–2339 m). The absolute species loss between 2001–2008 was 4, among which were 2 endemics. At the scale of individual summits, the highest changes were recorded at the lower summits with absolute species loss 4 in both cases. Paired t-tests for the total species richness at 1 m2 between 2001–2008, showed no significant differences. No significant differences were found at the individual summit level neither at the 5 m SAS or the 10 m SAS. Time series analysis reveals that soil mean annual temperature is increasing at all summits. Linear regressions with the climatic variables show a positive effect on species richness at the 5 m and 10 m SAS as well as species changes at the 5 m SAS. In particular, June mean temperature has the highest predictive power for species changes at the 5 m SAS. Recorded changes in species richness point more towards fluctuations within a plant community’s normal range, although there seem to be more significant diversity changes in higher summits related to aspects. Our work provides additional evidence to assess the effects of climate change on plant diversity in Mediterranean mountains and particularly those of islands which remain understudied.

Динамика растительности после сплошнолесосечных рубок ельников черничных (среднетаежная подзона европейского северо-востока России)

Динамика растительности после сплошнолесосечных рубок ельников черничных (среднетаежная подзона европейского северо-востока России)

Relationship between Species Richness, Biomass and Structure of Vegetation and Mycobiota along an Altitudinal Transect in the Polar Urals.

Aboveground species richness patterns of vascular plants, aphyllophoroid macrofungi, bryophytes and lichens were compared along an altitudinal gradient (80–310 m a.s.l.) on the Slantsevaya mountain at the eastern macroslope of the Polar Urals (Russia). Five altitudinal levels were included in the study: (1) Northern boreal forest with larch-spruce in the Sob’ river valley habitats; (2–3) two levels of closed, northern boreal, larch-dominated forests on the slopes; (4) crook-stemmed forest; (5) tundra habitats above the timberline. Vascular plant or bryophyte species richness was not affected by altitudinal levels, but lichen species richness significantly increased from the river valley to the tundra. For aphyllophoroid macrofungi, species richness was highest at intermediate and low altitudes, and poorest in the tundra. These results indicate a positive ecotone effect on aphyllophoroid fungal species richness. The species richness of aphyllophoroid fungi as a whole was neither correlated to mortmass stocks, nor to species richness of vascular plants, but individual ecological or morphological groups depended on these parameters. Poroid fungal species richness was positively correlated to tree age, wood biomass and crown density, and therefore peaked in the middle of the slope and at the foot of the mountain. In contrast, clavarioid fungal species richness was negatively related to woody bio- and mortmass, and therefore peaked in the tundra. This altitudinal level was characterized by high biomass proportions of lichens and mosses, and by high litter mortmass. The proportion of corticoid fungi increased with altitude, reaching its maximum at the timberline. Results from the different methods used in this work were concordant, and showed significant patterns. Tundra communities differ significantly from the forest communities, as is also confirmed by nonmetric multidimensional scaling (NMDS) analyses based on the spectrum of morphological and ecological groups of aphyllophoroid fungi.

Vascular plant species diversity of Mt. Etna (Sicily): endemicity, insularity and spatial patterns along the altitudinal gradient of the highest active volcano in Europe.

BackgroundAltitudinal variation in vascular plant richness and endemism is crucial for the conservation of biodiversity. Territories featured by a high species richness may have a low number of endemic species, but not necessarily in a coherent pattern. The main aim of our research is to perform an in-depth survey on the distribution patterns of vascular plant species richness and endemism along the elevation gradient of Mt. Etna, the highest active volcano in Europe.MethodsWe used all the available data (literature, herbarium and seed collections), plus hundreds of original (G Giusso, P Minissale, S Sciandrello, pers. obs., 2010–2020) on the occurrence of the Etna plant species. Mt. Etna (highest peak at 3,328 mt a.s.l.) was divided into 33 belts 100 m wide and the species richness of each altitudinal range was calculated as the total number of species per interval. In order to identify areas with high plant conservation priority, 29 narrow endemic species (EE) were investigated through hot spot analysis using the “Optimized Hot Spot Analysis” tool available in the ESRI ArcGIS software package.ResultsOverall against a floristic richness of about 1,055 taxa, 92 taxa are endemic, of which 29 taxa are exclusive (EE) of Mt. Etna, 27 endemic of Sicily (ES) and 35 taxa endemic of Italy (EI). Plant species richness slowly grows up to 1,000 m, then decreases with increasing altitude, while endemic richness shows an increasing percentage incidence along the altitudinal gradient (attributed to the increased isolation of higher elevation). The highest endemic richness is recorded from 2,000 up to 2,800 m a.s.l., while the highest narrow endemic richness (EE) ranges from 2,500 up to 2,800 m a.s.l. Life-form patterns clearly change along altitudinal gradient. In regard to the life-form of the endemics, the most represented are the hemicryptophytes, annual plants (therophytes) are prevailing at lower altitudes and show a decreasing trend with increasing elevation, while chamaephytes are featured by an increasing trend up to 3,100 m of altitude. Furthermore, the results of the hotspot analysis emphasize the high plant conservation priority areas localized in oro-mediterranean (1,800–2,400 m s.l.m.) and cryo-mediterranean (2,400–2,800 m) bioclimatic belts, in correspondence of the oldest substrates of the volcano.ConclusionsHigh plant speciation rate caused by increasing isolation with elevation is the most plausible explanation for the largest active volcano in Europe. The high degree of endemic species on Mt. Etna is linked to its geographical, geological and climatic isolation, all important drivers of speciation acting on the population gene flows. The hot spot map obtained represents a useful support for help environmental decision makers to identify priority areas for plant conservation.

Release of retained oaks in Norway spruce plantations. A 10-year perspective on oak vitality, spruce wood production and ground vegetation

This study explores the decade-long effects of release cutting around old retained oaks (Quercus robur L.) in a Norway spruce (Picea abies L. Karst) stand that was 33 year old when thinned. The impacts on both nature conservation values and spruce wood production were evaluated in a randomized block design. To release oaks from competition, stems of Norway spruce were cut around 33 oaks, in three different treatments: high release (HR), medium release (MR) and no release (NR). Trees within a circular sample plot (15 m radius from the oak) were measured at time of treatment and 10 years after. The treatment effects on stand development, oak vitality and understory vegetation were evaluated after ten years, using tree diameter, height measurements, oak crown and tree structure estimates as well as ground vegetation surveys. Release cutting did not impact spruce production within the sample plot, and given that there were no other obvious sources of spruce suppression in the stand, we speculate that release cutting has little to no impact at the stand scale. Oak crowns in the control plots (NR) became smaller after ten years, while the crowns expanded and colonized the gap in the release treatments. Simultaneously, the amount of dead wood in the crown increased among oaks in the control treatment, indicating dieback. Cover and species richness of vascular plants in the understory were significantly higher in the HR and MR treatments compared to NR. These results suggest that the creation of relatively wide gaps (greater than 2 m) around retained oak crowns is one efficient approach to maintain their conservation values in a spruce-dominated stand on a longer time frame. This will allow oaks to expand their crowns, increase their vitality and increase species richness and diversity of plants under the canopy. The economic loss of creating large gaps instead of no gaps may be negligible since the overall spruce production was not affected within 15 m of each oak.

Changes in species richness of vascular plants under climate and solar radiation in the Middle Volga River region (Russia)

Specially protected natural conservation areas in the Middle Volga River region serve to preserve both rare and endangered species and the entire biotic complex, including typical floristic communities of vascular plants. We have identified 25 sites, 100 km2 each, where the flora is represented in full the most. We studied the relationships between the general species richness (SR) and the richness of particular life forms (LF) of vascular plants with climate and relief using multiple regression methods. Our study shows that the special function of March precipitation is the factor that influences the most the spatial change of the SR and LF. When increasing the precipitation in the model by only 1 mm, this leads to a decrease in the number of species by 7.1%. Winter precipitation and temperature are important factors as well; together they are responsible for 70-82% of the SR variation. These close links made it possible to develop the maps of the species richness of the study area. The SR model did not include solar radiation, one of the most important environmental factors, as a significant predictor. This factor was omitted due to the analysis of the number of species of particular LF, which showed the maximum illumination of the slopes as a highly significant factor for number of them. The two dominant LFs (hemicryptophytes and therophytes), which account for 73% of the total number of species, depend oppositely on the illumination. This fact indicates a decrease in competition between LFs due to their separation in space, since hemicryptophytes, in contrast to therophytes, predominate on well-illuminated slopes. In addition, opposite LF responses lead to omitting of illumination factor from the SR model for all species in the region.

Effects of management cessation on hoverflies (Diptera: Syrphidae) across Austrian and Swiss mountain meadows

Abstract. Extensively managed grasslands, particularly in mountain regions, are considered to be one of the most diverse agroecosystems worldwide. Their decline due to land use abandonment affects the diversity of both plants and associated pollinators. Extensive grasslands constitute an important habitat type and food resource for hoverflies (syrphids); however, not much is known about the effects of abandonment on this important pollinator group. In the present study, we investigated how abandonment affects species richness and the composition of syrphids in mountainous meadows. We recorded the richness of vascular plants, vegetation cover, flower cover and the surrounding landscape to examine whether and how syrphids are affected by plant and landscape parameters. We investigated the species richness, abundance and species composition of syrphids by sweep netting and by using observation plots in 18 semidry meadows across two Austrian regions and one Swiss region. For each region, we selected three meadows abandoned for more than 20 years and three annually mown non-fertilized meadows. Abandonment or mowing had no significant effect on the total number of syrphid species or individuals or on the number of aphidophagous and non-aphidophagous species and individuals. However, the total number of species and the number of non-aphidophagous species significantly increased with the increasing number of plant species. The surrounding landscape and other plant parameters showed no association with the assessed syrphid parameters. Although syrphids were unaffected by abandonment, higher syrphid species numbers in response to a higher plant richness in annual mown meadows suggest that the management of mountain meadows is beneficial in preserving syrphid richness.

Conservation values of understory vascular plants in even- and uneven-aged Nothofagus antarctica forests

Usually, stands with aging trees are considered forests with higher conservation values, regardless their structural diversity and other functional attributes. Natural stands present a wide range of age structures, from even-aged stands growing at different development growth phases (e.g. CO = stands at initial or final optimum development growth phase, MD = stands at mature or decaying development growth phases) to uneven-aged stands with mixed development growth phases (e.g. UOG = stands combining mature or decaying development growth phases with initial or final optimum development growth phases, UMD = stands combining only mature and decaying development growth phases). The aim of this work was to compare richness and cover of understory vascular plants of even- and uneven-aged stands of Nothofagus antarctica (nire) forests in Tierra del Fuego (Argentina), and relate these characteristics with abiotic, soil and forest structure variables. A total of 75 stands were sampled across the natural range distribution of the forests, where understory (point intercept method), forest structure (angle count sampling and eye-fish photos) and environmental (soil) variables were measured. 17 one-way ANOVAs were conducted using Tukey test at p UOG > MD > CO (17–28 total, and 13–24 native species, respectively). Neither exotic species richness (4–5 species) nor understory cover significantly changed among treatments (total, dicots, ferns and bryophytes). However, monocots cover significantly differed among treatments (F = 3.9, p = 0.012), where UMD > MD > UOG > CO. Finally, indicator species cover for environmental degradation did not present significant differences (F = 2.1, p = 0.106), but they were positive related to forests growing in mature stages. We concluded that uneven-aged stands presented significantly higher conservation values compared to even-aged stands, where mature/decay stands have better conservation values than optimum growth development phases. These findings can be used for better silviculture practices that combine silvopastoral use and conservation strategies.

Competitive dominance mediates the effects of topography on plant richness in a mountain grassland

Small-scale landforms influence plant species richness, but their mechanisms and effects in semi-natural dry grasslands have been poorly investigated. In this study we compared vascular plant richness, species composition, plant traits, soil properties and biomass nutrient content of convex (hillocks) and concave (hollows) karst landforms in a mountain pasture of the Central Apennines (Italy), at a small spatial scale (1 m2 plots). We found hillocks had significantly higher species richness than hollows. On hillocks, smaller Specific Leaf Area and Lateral Width, together with greater allocation of resources to Below-Ground Organs, indicated lower water availability, whereas hollows had deeper (thus moister), more acidic and more fertile soils, with aboveground plant biomass displaying higher nutrient levels. Partial correlation and regression tree models suggested that fine-scale richness patterns were not directly determined by abiotic properties, but were rather the result of competition levels associated with the cover of Agrostis capillaris (=A. tenuis) – a calcifuge and drought-sensitive grass able to achieve dominance only in hollows. The higher functional convergence exhibited by hollows suggests that A. capillaris is a strong competitor both above- and below-ground, mediating the effects of topography by imposing a biotic filter. On hillocks, competition is released by lower levels of available soil water in summer and higher soil pH, resulting in higher species richness and a more functionally divergent assemblage.

Species richness patterns of vascular plants and their drivers along an elevational gradient in the central Himalayas

How and why biodiversity varies along the elevational gradients is fundamental yet controversial topics in ecology. To advance our understanding on these questions and provide insight into biological conservation, we explore the elevational patterns of vascular plant richness and their drivers in the Gyirong Valley, the longest valley in China’s Himalayas. Elevational richness patterns of vascular plant were documented by 96 sampling plots along 12 elevational bands of 300-m ranging from 1800 to 5400 m above sea level. We related the elevational patterns of vascular plant richness to the climate, spatial, historical, and disturbance factors, and assessed the relative importance of these factors in explaining above patterns using the Random Forest model. Overall, the species richness of vascular plant showed a hump-shaped pattern along the elevational gradient in the Gyirong Valley, although the life form and endemism of species in combination with the scale effect modified the patterns observed. Climate factors played a greater role than other environmental factors in explaining the elevational pattern of vascular plant richness. Such strong climate-species relationship was nicely interpreted by the water-energy dynamic hypothesis, indicating the combined effect of energy and water is the major driver that shaped vascular plant richness along elevational gradient. The climate-driven hump-shaped pattern of vascular plant in the Gyirong Valley is aligned with most of previous report from different part of the Himalayas, highlighting the need for more conservation effort at the intermediate elevations of this region, and calling for more scientific concern on the impact of climate change on elevational pattern of biodiversity.

Comparing the effect of landscape context on vascular plant and bryophyte communities in a human‐dominated landscape

AbstractAimsIt is important to understand the effect of landscape context on biological communities to predict how biodiversity will be affected on human‐dominated landscapes. While many studies have tested the effects of landscape context on the species richness and composition of vascular plants, few have compared the responses of vascular plants and bryophytes on the same landscape. We sampled non‐epiphytic bryophytes and vascular plants in 184 plots to test whether three landscape context factors measured four years or four decades previously could predict bryophyte or vascular plant species richness and composition after accounting for local factors.LocationTemperate forests and oak savannahs, Vancouver Island, British Columbia, Canada.MethodsWe used model selection and comparisons to test the effects of surrounding road density, total amount of forest, and distance to the nearest forest edge on species richness, species richness of non‐disturbance‐associated species, and community composition after controlling for important local predictors including substrate availability and topography.ResultsThe species richness of non‐disturbance‐associated vascular plants was lower in plots with greater surrounding historical road density, and perennial stayer bryophyte richness declined with increasing historical road density and lower historical forest amount, suggesting a potential extinction debt. Landscape context significantly affected total species richness and community composition of vascular plants, but not bryophytes.ConclusionWhile bryophytes appear to be less sensitive overall to landscape context than vascular plants, disturbance‐intolerant perennial stayer bryophytes may decline in the future in response to the increased road density and loss of forest cover that has occurred over the past four decades.

Species richness and beta diversity patterns of multiple taxa along an elevational gradient in pastured grasslands in the European Alps

To understand how diversity is distributed in space is a fundamental aim for optimizing future species and community conservation. We examined in parallel species richness and beta diversity components of nine taxonomic groups along a finite space, represented by pastured grasslands along an elevational gradient. Beta diversity, which is assumed to bridge local alpha diversity to regional gamma diversity was partitioned into the two components turnover and nestedness and analyzed at two levels: from the lowest elevation to all other elevations, and between neighboring elevations. Species richness of vascular plants, butterflies, beetles, spiders and earthworms showed a hump-shaped relationship with increasing elevation, while it decreased linearly for grasshoppers and ants, but increased for lichens and bryophytes. For most of the groups, turnover increased with increasing elevational distance along the gradient while nestedness decreased. With regard to step-wise beta diversity, rates of turnover or nestedness did not change notably between neighboring steps for the majority of groups. Our results support the assumption that species communities occupying the same habitat significantly change along elevation, however transition seems to happen continuously and is not detectable between neighboring steps. Our findings, rather than delineating levels of major diversity losses, indicate that conservation actions targeting at a preventive protection for species and their environment in mountainous regions require the consideration of entire spatial settings.