Abundance Of Plant Species Research Articles

Thermodynamic analysis of an ecologically restored plant community:Number of species

Conducting a thermodynamic analysis of a plant community can be an approach to macro-ecology that emphasizes not only the diversity and abundances of plant species but also the exchange of matter and energy among species within the community and that with its physical and biological environment. The experimental data used for the test were obtained from an ecological restoration project implemented at a manganese tailing site. The relations derived from the maximal discrete entropy theorem show that the maximum entropy will increase with increase in the total number of species N, suggesting that N has an upper limit Nm at a habitat subject to its heterogeneity in physical conditions and species resource in its surrounding areas. As an important macroscopic property of an ecosystem, N is the number of species that are present at a habitat while its upper limit Nm is the potential number of species that have been or can be adapted to the physical conditions of the habitat, and can thus possibly be present at the habitat. As a function of the maximum entropy, ln(N) is applied as a biodiversity index. As an upper limit of ln(N), ln(Nm) can be regarded as a biodiversity potential index as it takes into account the available number of species distributed in the surrounding areas of the habitat, showing the potential limit for further increase in its biodiversity. Following the thermodynamic laws, given that there is no further change in system enthalpy H, ∆H = 0, the equilibrium number of species Neq can be found at the point ∆N = 0 and Nm can be determined by Nm = Neq2. The restoration of the investigated plant community was shown to be an irreversible process characterized by spontaneous increases in its total biomass and total number of plant species associated with increases in its enthalpy, Gibbs free energy and entropy. The analytical results gave support to the argument that the internal energy factors of a plant community are functions of its productivity and biodiversity and the difference between ln(N) and ln(Nm) determines its internal energy distribution.

Functional traits predict resident plant response to Reynoutria japonica invasion in riparian and fallow communities in southern Poland.

Reynoutria japonica is one of the most harmful invasive species in the world, dramatically reducing the diversity of resident vegetation. To mitigate the impact of R. japonica on ecosystems and properly manage affected areas, understanding the mechanisms behind this plant’s invasive success is imperative. This study aimed to comprehensively analyse plant communities invaded by R. japonica, taking into account species traits, habitat conditions and seasonal variability, and to determine the ecological profile of species that withstand the invader’s pressure. The study was performed in fallow and riparian areas in southern Poland. Pairs of adjacent plots were established at 25 sites with no obvious signs of recent human disturbance. One plot contained R. japonica, and the other contained only resident vegetation. For each plot, botanical data were collected and soil physicochemical properties were determined. Twelve sites were surveyed four times, in two springs and two summers, to capture seasonal variability. The presence of R. japonica was strongly associated with reduced resident plant species diversity and/or abundance. In addition to the ability to quickly grow and form a dense canopy that shades the ground, the success of the invader likely resulted from the production of large amounts of hard-to-decompose litter. The indirect impact of R. japonica by controlling the availability of nutrients in the soil might also play a role. A few species coexisted with R. japonica. They can be classified into three groups: (i) spring ephemerals – geophytic forbs with a mixed life history strategy, (ii) lianas with a competitive strategy and (iii) hemicryptophytic forbs with a competitive strategy. Species from the first two groups likely avoided competition for light by temporal or spatial niche separation (they grew earlier than or above the invasive plant), whereas the high competitive abilities of species from the third group likely enabled them to survive in R. japonica patches.

Natural Carbon Sinks Linked to Pastoral Activity in S Spain: A Territorial Evaluation Methodology for Mediterranean Goat Grazing Systems

Exploring and developing new tools for the accounting and management of natural C sinks will provide a closer, more accurate option to remark the importance of such sinks in relation to livestock production, helping to support the persistence of some seriously endangered traditional, environmentally sustainable livestock farming. Following both precision and usability criteria, two main C sink databases covering the Andalusian region (S Spain) were developed from the Spanish Land Parcel Identification System (SIGPAC, coarse resolution) and the Spanish Information System on Land Cover (SIOSE, finer resolution) land use classes. Particular C sink factors based on growth rates for individual plant species were associated with detailed vegetation maps and, further, were linked to Land Use and Covers cartography across the region. In addition, eight ruminant farms were exhaustively studied in situ and used as a control. Results were compared with the obtained through the application of the developed C sink databases, and with the commonly used Petersen methodology. The sink capacity of vegetation associated with farms varied from 0.25 to 1.37 t CO2 ha−1 year−1, depending on the plant species composition and abundance. All the approaches showed significant differences from the control. C sink values were significantly higher when applying SIGPAC-based C sink database to farms, while values from the SIOSE and Petersen methodology approaches provided more moderate values, closer to the control. SIGPAC and Petersen approaches showed higher usability but presented lower precision due to a poor definition of plant cover. SIOSE-based C sink database provided suitable values able to be adapted to reality and used by farmers. In this regard, further research efforts to improve the adjustment of results and ease of use are required. The present approach means a methodological advance in the estimation of the C sink capacity associated with pastoral livestock farms, able to be incorporated into the CF calculation in contrasted areas worldwide, in the frame of the ‘eco-schemes’ being recently under development through the EU CAP.

Fuel load, stand structure, and understory species composition following prescribed fire in an old-growth coast redwood (Sequoia sempervirens) forest

BackgroundWith the prevalence of catastrophic wildfire increasing in response to widespread fire suppression and climate change, land managers have sought methods to increase the resiliency of landscapes to fire. The application of prescribed burning in ecosystems adapted to fire can reduce fuel load and fire potential while minimizing impacts to the ecosystem as a whole. Coast redwood forests have historically experienced fire from both natural and anthropogenic sources, and are likely to respond favorably to its reintroduction.ResultsRandom sampling was conducted in three burned sites and in three unburned sites, in an old-growth coast redwood (Sequoia sempervirens [D. Don] Endl.) forest. Data were collected on fuel, forest structure, and understory species composition and compared between treatments. Downed woody fuel, duff depth, litter depth, and density of live woody fuels were found to be significantly lower on sites treated with fire compared to unburned sites. Density of the dominant overstory canopy species, coast redwood and Douglas-fir (Pseudotsuga menziesii var. menziesii [Mirb.] Franco), remained consistent between treatments, and the abundance of herbaceous understory plant species was not significantly altered by burning. In addition, both downed woody fuel and live fuel measures were positively correlated with time since last burn, with the lowest measures on the most recently burned sites.ConclusionsOur results indicated that the use of prescribed burning in old-growth redwood forests can provide beneficial reductions in live and dead surface fuels with minimal impacts to overstory trees and understory herbaceous species.

Biodiversity effects on grape quality depend on variety and management intensity.

Interactions between plants can be beneficial, detrimental or neutral. In agricultural systems, competition between crop and spontaneous vegetation is a major concern. We evaluated the relative support for three non‐exclusive ecological hypotheses about interactions between crop and spontaneous plants based on competition, complementarity or facilitation.The study was conducted in Swiss vineyards with different vegetation management intensities. In all, 33 vineyards planted with two different grape varieties were studied over 3 years to determine whether low‐intensity vegetation management might provide benefits for grape quality parameters. Management intensity varied with the degree of control of spontaneous inter‐row vegetation. Features of spontaneous vegetation measured included total cover, total species richness and abundance of nitrogen‐fixing plants. Grape quality parameters of known importance to wine making (yeast assimilable nitrogen, sugars, tartaric acid and malic acid) were determined by Fourier‐transform infrared spectroscopy (FTIR). Using structural equation modelling, we evaluated hypotheses about the multivariate responses of grape quality parameters as well as the direct and indirect (plant‐mediated) effects of management.Observed effects of management differed between grape varieties. Management intensity and abundance of N‐fixing plants significantly influenced grape quality parameters while total richness of spontaneous plants did not have detectable effects. Abundance of N‐fixing plants was enhanced by low‐intensity management resulting in increased N content in the red grape variety Pinot noir, potentially enhancing grape quality, while measured soil N content did not explain the increase.Synthesis and applications. Our study shows that crop quality can be enhanced by spontaneous plants, in this case by the abundance of a key functional group (N‐fixers), most likely through plant–plant or plant–microbe facilitation. However, beneficial interactions may have a high specificity in terms of facilitation partners and may have contrasting effects at low taxonomic resolutions such as crop varieties. Generally, increasing plant biodiversity in agricultural systems may increase competition with crops. Thus, the identification of suitable interaction partners and a careful balance between crop variety and spontaneous plant species may be necessary to utilize beneficial interactions and to reduce the trade‐off between agricultural production and biodiversity to achieve a sustainable ecological benefit in agricultural systems.

Habitat determines plant community responses to climate change in the High Arctic

Plant climate responses may depend on site-specific environmental context. Using fences and open-top chambers, we enhanced snow depth (creating Ambient, Medium, and Deep regimes) over an 11-year period and increased temperatures for two summers in dry heath and mesic meadow habitats on Svalbard, Norway. Comparison of plant growth form abundance and diversity responses in these two habitats showed that the response was more limited in the dry heath than in the mesic meadow. Common to both habitats was a decrease in shrub abundance and vascular plant species richness in the Deep snow regimes. Bryophyte abundance increased with enhanced snow cover in both habitats, but only up to a certain extent of snow depth in the meadow. However, for many growth forms, the effects of snow enhancement were habitat specific. In the mesic meadow, the abundance of forbs and bryophytes increased with snow enhancement, but the effect was stronger when combined with summer warming. The “bryofication” — that is, an increased abundance of bryophytes in response to snow enhancement and summer warming — also influenced overall plant diversity in the mesic meadow. Bryophytes are species-rich taxa and may respond differently than vascular plants to environmental change. We show that the inclusion of even the most common bryophytes in measures of diversity may determine overall plant diversity responses to environmental change in the Arctic.

Large standard trees and deadwood promote functional divergence in the understory of beech coppice forests

How species assemble in a community is still an unresolved question in ecology, especially in forest ecosystems. In temperate forests, the understory layer includes most of the plant diversity and significantly contributes to ecosystem functions. Understory communities are susceptible to changes in environmental conditions linked to forest structural features. Understanding how understory assemblages respond to these features can provide useful suggestions for sustainable forest management. We selected 68 abandoned coppice-with-standards beech forest stands in central Italy. We recorded plant species presence and abundance and several structural variables, including total stem density, height and basal area of standard trees, the abundance of lying deadwood, and shrub layer cover. Different plant traits informative on key ecological functions were attributed to understory plants to calculate the single- and multi-trait functional diversity (FD) expressed as Rao's quadratic entropy. Linear-mixed models were used to assess the relationship between structural parameters and single- and multi-trait FD. We found that the size of standard trees and lying deadwood were the main structural drivers of trait-based understory assemblages. Larger standards and a higher amount of lying deadwood contributed to reduce multi-trait convergent patterns or to shift patterns from convergence to divergence (for reproductive height, seed mass, specific leaf area, and leaf area), probably due to modulation of resource amount and heterogeneity (i.e., light and nutrients). Our results feed the debate on the sustainable management of coppice forests. We suggest that the understory functional diversity of montane beech forests could be enhanced if forest management practices allow the release of larger standards (height > 19 m; basal area > 35 m2/ha) and the accumulation of deadwood (cover > 7%).

Habitat use and feeding behavior of domestic free-ranging goats in a seasonal tropical dry forest

Traditional pastoralism based on free-ranging goats is indispensable for the rural economy of millions of people in the Brazilian Caatinga drylands. The use of landscape as rangelands for domestic herbivores benefits humans, but understanding its impacts on vegetation is crucial to sustainable strategies. Here we assessed how free-ranging domestic goats use mixed working landscapes in the largest dry forest of the Americas. We evaluated habitat use via GPS tracking and analysis of feeding preferences. Goats preferentially used open areas near human settlements and their impact on plant community may be negligible because they feed mostly on plants widely available in modified environments. Although free-ranging, the area of use was nearly constant (95.44 ha), but the size of herds varied (2–100 animals). Our study suggests that domestic goats can be considered dwellers of human-modified landscapes, foraging close to villages, on open (i.e., degraded) areas where abundant plant species thrive. Therefore, the extensive goat pastoralism in the Caatinga may have little impact on natural vegetation and could be sustainably managed under traditional management practices.

Determinants of vegetation regeneration on forest roads following restoration treatments: implications for boreal caribou conservation

Linear features are increasing worldwide and, in many jurisdictions, their decommissioning has been identified as a way to restore wildlife habitat. Few studies have assessed restoration practices on forest roads, yet they are the main linear disturbance throughout most circumboreal forests. In boreal forests of eastern Canada, such knowledge would be especially valuable for the conservation of boreal populations of woodland caribou (Rangifer tarandus caribou). We assessed the short‐term establishment of vegetation following four treatments applied across 40 km of forest roads, along a restoration gradient involving additive treatments (i.e. each successive treatment included the treatments prior): closing the road to traffic, decompacting the soil, planting black spruce trees, and adding enriched soil. We linked lateral cover (a proxy of movement obstruction for wildlife) and the occurrence and abundance of plant species to road treatments and environmental covariates. Vegetation establishment 3–4 years after decommissioning was mostly influenced by treatments but also by road width and stand composition in the vicinity of roads. The combination of closing, decompacting, and planting was the most effective treatment to establish regeneration that would lead to suitable caribou habitat as it reduced food availability for moose and bears (i.e. lower presence of herbaceous species, fruit‐bearing shrubs, and deciduous trees). It also reduced the presence of plants competing with spruce, such as ericaceous shrubs. Our results suggest that the decommissioning of forest roads could benefit caribou, provided it is performed at a sufficiently broad scale, and accompanied by other habitat restoration and protection practices.

Three decades of declining natural foods alters bottom-up pressures on American black bears

Wildlife management entails the manipulation of bottom-up and top-down forces that affect populations. For bear management in North America, both food availability (bottom-up) and hunting pressure (top-down) can limit population growth. Whereas seasonal and year-to-year variation in production of fruits and nuts (i.e., primary bear foods) has been widely recognized, long-term trends in natural food production have rarely been reported. Here we compared the current (2015–2019) availability of 18 fruits and nuts representing the main foods of American black bears (Ursus americanus) in north-central Minnesota to what was available three decades earlier (1980s) on the same study area. Timber harvesting was routine in the 1980s but less intensive in recent decades, prompting us to hypothesize that forests matured and consequently produced less fruit for bears due to increased shade. Within each of 12 forest types, we measured the abundance, productivity and biomass (kg/ha) of each fruit-bearing plant species using the same methodology as in the 1980s. Bootstrapped independent two-sample t-tests identified species-specific changes in food availability between the two sampling periods. Generalized linear mixed-effects models were used to quantify changes for groups of fruit-producing species (i.e., summer/fall foods and short/tall shrubs). For all these groups, availability of the fruiting species changed little, but the probability of forest stands producing any fruit at all in the recent time period (~40%) was nearly half what it was in the 1980s (~80%). At the landscape scale, we estimated a ~70% decline in fruit biomass. Our hypothesis that this decline was due to reduced timber harvesting and thus denser canopy was only partially correct, as we observed the same decline in fruit production within forests of the same type and canopy closure, and also along edges of stands with high light penetration. Decline in fruit availability was due more to a complete lack of production in some stands of the same type and age rather than to general forest maturation. We explored three alternate hypotheses to explain this decline: (1) change in weather (which could affect fruiting directly, or cause issues with pollination), (2) increase in invasive earthworms, and (3) increased deer browsing. None of these were completely consistent with our findings, although it appeared from the extreme spatial variability in fruit production that on-the-ground factors were more of a driving force than weather. The magnitude and complexity of this change in bottom-up forces is a serious issue for bear management.

Traits as determinants of species abundance in a grassland community

AbstractQuestionsThe patterns in abundances of plant species and the processes which determine these patterns have been intensively studied. While recent investigations have recognized plant functional traits as important determinants of species abundances, intraspecific trait variability as a driver of species abundance patterns has largely been ignored. The objective of this study was to quantify the effect of intraspecific trait variability and trait dissimilarity from mean community characteristics (community‐weighted mean [CWM]) on the abundance of six widely distributed grassland species, while controlling for the possible influence of environmental conditions for three commonly used plant functional traits (Plant height — PH; specific leaf area — SLA; and leaf dry matter content — LDMC).LocationSpecies‐rich alvar grasslands in western Estonia.MethodsWe quantified the discrete effects of environmental conditions, intraspecific trait variability, and trait difference from CWM on species abundance and assessed individual contributions of both traits and environmental characteristics on species abundance patterns.ResultsWe found a strong and consistent relationship between species’ abundance and their intraspecific trait variability, where the biggest proportion of variation was explained by PH and SLA respectively. Local populations with larger PH and LDMC, and lower SLA were more abundant compared to populations having different values of these traits. Significant unimodal dependence of species abundance on CWM was detected for two species for which the optimum values of SLA and LDMC were close to the CWM values. For other species, the relationship between optimum trait values and CWM values was monotonous. The effect of measured environmental conditions (e.g., soil depth, above‐ground biomass, and soil fertility) and trait difference from CWM on species abundance patterns was minor when compared to the effect of intraspecific trait variability.ConclusionsOur study demonstrated a strong relationship between intraspecific trait variability and local performance of species within communities.

Unraveling plant strategies in tidal marshes by investigating plant traits and environmental conditions

AbstractAimsTidal marsh vegetation along estuaries is exposed to strong environmental gradients that determine which species — enabled through specific traits — can establish and persist. With these ecosystems under anthropogenic pressure, in‐depth knowledge on the conservation of remaining tidal wetlands and restoration potentials is needed. In this study we elaborate the habitat conditions in the natural vegetation of the Elbe estuary and analyze: (a) which abiotic factors drive species composition; and (b) which species traits are key to the plants’ strategies in this specific ecotone.LocationThree sites in the Elbe estuary (river kilometer 671–703).MethodsWe collected data on soil nutrients, inundation period and wave height and sampled traits of the 17 most abundant plant species, which we analyzed by RLQ (three‐table analysis, including environment variables [R], species abundance [L] and a species traits table [Q]).ResultsWe detected a strong ˈwave–disturbance–inundation gradientˈ, which separated sparsely vegetated low‐lying plots receiving high wave impact and exposed to long inundation periods, from high‐lying plots showing dense vegetation and aerated soils. Close to the shore, plants showed low organ density and high investment into rhizomes, with a correlation of 0.72 between mass fraction of rhizome and phosphorus content of rhizome tissue. On higher elevations, plants strongly expressed traits relating to competition, like high allocation to stem biomass. Further, we found species with high leaf chlorophyll content showing low specific leaf area values and a negative correlation with the nutrient gradient.ConclusionThe results of our study are particularly relevant for restoration measures in order to re‐establish healthy marsh vegetation. However, changes in the environmental conditions, for instance stronger wave energies by a higher shipping frequency in the river channel and sea level rise may trigger changes in species composition through plant trait adaptations, for example by demanding a stem flexibility beyond what would be structurally feasible.

Effect of Soil Diversity on Forest Plant Species Abundance: A Case Study from Central-European Highlands

Plant distribution is most closely associated with the abiotic environment. The abiotic environment affects plant species’ abundancy unevenly. The asymmetry is further deviated by human interventions. Contrarily, soil properties preserve environmental influences from the anthropogenic perturbations. The study examined the supra-regional similarities of soil effects on plant species’ abundance in temperate forests to determine: (i) spatial relationships between soil property and forest-plant diversity among geographical regions; (ii) whether the spatial dependencies among compared forest-diversity components are influenced by natural forest representation. The spatial dependence was assessed using geographically weighted regression (GWR) of soil properties and plant species abundance from forest stands among 91 biogeographical regions in the Czech Republic (Central Europe). Regional soil properties and plant species abundance were acquired from 7550 national forest inventory plots positioned in a 4 × 4 km grid. The effect of natural forests was assessed using linear regression between the sums of squared GWR residues and protected forest distribution in the regions. Total diversity of forest plants is significantly dependent on soil-group representation. The soil-group effect is more significant than that of bedrock bodies, most of all in biogeographical regions with protected forest representation >50%. Effects of soil chemical properties were not affected by protected forest distribution. Spatial dependency analysis separated biogeographical regions of optimal forest plant diversity from those where inadequate forest-ecosystem diversity should be increased alongside soil diversity.

Plant‐caterpillar food web: Integrating leaf stoichiometry and phylogeny

1. Trophic interactions and plant‐herbivore network structure may be regulated by ecological and evolutionary factors. The allocation of resources to physical and chemical traits may influence plant nutritional values and defence against insect herbivores. However, the elemental consistency of plant leaves is rarely considered a functional trait, despite leaf chemical traits being critical for understanding trophic interactions and network modularity.2. We constructed a high‐resolution network of a plant‐caterpillar food web in a subtropical forest in southern China using DNA barcoding. We analysed whether abundance, phylogeny, and functional traits (including leaf chemical elements) significantly differed among modules and conducted linear regressions to explore how these traits could explain the intensity and likelihood of trophic interactions between plants and caterpillars.3. Caterpillar feeding intensity increased with increasing specific leaf area and leaf nitrogen to phosphorus (N:P) ratio. The intensity and likelihood of feeding decreased with increasing calcium and magnesium levels. Leaf dry matter content and leaf concentrations of potassium, magnesium, copper, and manganese varied among modules. Caterpillar feeding likelihood and intensity were constrained by plant and caterpillar phylogenies, and module phylogenetic clustering was apparent. Species abundance of plants and caterpillars constrained the feeding intensity but not the likelihood of feeding and network module composition.4. We highlighted the combined roles of functional traits and phylogeny in shaping trophic interactions and modularity in plant‐insect herbivore networks and illustrated the importance of leaf stoichiometry in establishing dietary associations.

Ethno - Botanical Survey Of Plant Species Used For Mosquito Control In Nigeria

In Nigeria, there is paucity of information on plants used to repel or kill mosquitoes despite the abundant plant species in the country’s tropical rain forests. Majority of available data are on the traditional use of plants for curative purposes. This study documents some plant species used for insecticidal or repellent purposes against mosquitoes in Nigeria. An ethno-botanical survey was carried out in four geo-political zones in the country using structured questionnaires and focus group discussion. A total of six plant species belonging to five families were reported in Delta state with Conyza Canadensis (Compositae) being the most utilized (50%) and Aspilia africana (Compositae), the least mentioned (5.60%). In Enugu state, a total of nine plant species belonging to eight families were mentioned by respondents with Aframomum melegueta the most utilised (26.09%) while Agava sisalana and Dracaena manii belonging to the families Agavaceae and Dracaenaceae were the least mentioned (1.09% each). A total of six plant species belonging to five families were reported in Kaduna State with Lantana camara belonging to the family Verbenaceae accounting for 58.82% of the utilised plant species for mosquito control while Ipomea asarifolia, Terminalia catappa and Citrullus vulgaris belonging to the families Convolvulaceae, Combretaceae and Cucurbitaceae respectively were the least utilized (5.88% each). Lagos State recorded the highest number of plant species (twenty five) belonging to eighteen families. Spondia mombin belonging to the family Lilaceae was the most mentioned (7.33%) while the least mentioned (0.37% each) were Magnifera indica, Baphia nitida and Pennisetum purpeum belongingto the families Anacardiaceae, Fabaceae and Poaceae respectively. There is a need for further investigation on these plant species as they may constitute potential sources of cidal and repellent compounds against a wide range of insect pests.
 Keywords: Ethno-botanical survey, insecticidal, repellence, mosquitoes, plant species

Rapid Changes in Ground Vegetation of Mature Boreal Forests—An Analysis of Swedish National Forest Inventory Data

The boreal forest floor vegetation is critical for ecosystem functioning and an important part of forest biodiversity. Given the ongoing global change, knowledge on broad-scale changes in the composition and abundance of different plant species and species groups is hence important for both forest conservation and management. Here, we analyse permanent plot data from the National Forest Inventory (NFI) on changes in the vegetation over a 10-year period in four regions of Sweden. To limit the direct and relatively well-known effects of forest management and associated succession, we only included mature forest stands not influenced by forestry during the 10 years between inventories, and focused on vegetation change mainly related to other factors. Results show strong decrease among many species and species groups. This includes dominant species such as Vaccinimum myrtillus and Deschampsia flexuosa as well as several forest herbs. The only species increasing are some mosses in the southern regions. Our data do not allow for a causal interpretation of the observed patterns. However, the changes probably result from latent succession in combination with climate change and nitrogen deposition, and with time lags complicating the interpretation of their relative importance. Regardless of the cause, the observed changes are on a magnitude that suggest impacts on ecosystem functioning and hence highlight the need for more experimental work.

Effects of Diet Selection by Goats Grazing on the Vegetation of a Protected Pine Forest in Doñana Natural Park (SW Spain)

We investigated the relationship between feeding selection by goats and changes in plant species abundance in the shrubland of a pine forest in Doñana Natural Park along three years. The abundance of the shrub species was measured using the point-intercept method. Goat preferences for shrub species were determined through direct observation. Goats showed selective feeding, since their browsing behavior was not related to species abundance. Myrtus communis was the overall preferred species (almost half of the bites belonged to this species, despite its low abundance) throughout the monitored years and seasons. Half of the species were selected some years while discarded others; two species were never grazed (Daphne gnidium and Thymus mastichina) and nine others were always ingested below their abundance. Within a year, species were consumed in certain seasons but not in others. The detected changes in species abundance were not related to the feeding preferences of the goats. The influence that grazing selectivity exerts on vegetation composition and abundance has long been recognized, but our study suggests that the mechanical effect of grazing herbivores on vegetation (pawing, scratching, and lying) may portrait a more important role than attributed to date.

Assessing species abundance and habitat preferences in a part of Nanda Devi Biosphere Reserve, western Himalaya

Present study is an attempt to understand the plant species abundance and habitat preferences using multivariate method in Nanda Devi Biosphere Reserve (NDBR), in western Himalaya. Soil, altitude, slope and differences are reported to be the most important parameters shaping the plant community in the mountains. Two representative areas i.e., Pindari–Sunderdhunga–Kafni site (PSK) of Kumaun region and Lata–Tolma–Phagti site (LTP) of Garhwal region with nineteen forest communities in buffer zone of NDBR have been investigated. All the forest communities were analyzed for assessing community composition and species density in relation to environmental variables. Out of 451 plant species recorded from the study sites, there was a dominance of herbs (70.5%) followed by shrubs (17.7%) and trees (11.8%). Maximum tree density in PSK and LTP sites was recorded in Betula utilis (535 ind ha−1) and mixed T. wallichiana–A. pindrow (1211 ind ha−1) communities respectively. The disturbed habitats in low to mid elevation areas are represented by low canopy cover and high seedling density in PSK site and high non-native species density in LTP site. Both the study sites are dominated by Betula utilis, Taxus wallichiana, Abies pindrow in high elevation areas securing high density of native and endemic species. Habitat preferences of different important species indicate their range of distribution and choice of association with other species.

Distribution of the Macrophyte Communities in the Danube Reflects River Serial Discontinuity

The Danube is the second-longest river in Europe that is subjected to various man-made alterations, including those related to hydro-power plants. We surveyed and analyzed the presence and abundance of macrophytes in the main channel from 2582 river kilometers (rkm) to 171 rkm. We also assessed selected habitat parameters in the sampled river stretches. Sixty-eight different plant species were recorded along the entire course. Among neophytes, we found Elodea nuttallii, E. canadensis, Vallisneriaspiralis and Azolla filiculoides. Based on similarity analysis, we distinguished 15 plant communities, most of which were defined as associations, which were classified into 5 alliances and represented three vegetation classes, namely vegetation of rooted hydrophytes Potamogetonetea, the vegetation of pleustophytes Lemnetea and vegetation of marshes Phragmitetea. The number and abundance of plant species, as well as plant communities recorded in single stretches, varied along the course. Canonical correspondence analysis (CCA) revealed that environmental parameters explained 21% of plant species composition. CCA runs with neophytes explained 41% of the variance, and current velocity, water transparency, species number and bank structure were significant variables. The present study revealed that the free-running sections of the river are poor in number and abundance of plant species, whereas impounded reaches mainly show an opposite result.

Arbuscular mycorrhizal traits are good indicators of soil multifunctionality in drylands

Drylands are highly susceptible to degradation and climate change, which has important ecological and socio-economic consequences worldwide. To halt drylands degradation, plant species selection for restoration is starting to include also a functional approach, but does not integrate belowground functional traits yet. Therefore we tested the use of mycorrhizal traits to identify native plant species which host guilds of beneficial microbes and therefore enhance multiple soil functions simultaneously – soil multifunctionality. We used a soil organic matter (SOM) gradient (0.9–1.9%) and evaluated the effect of 14 common and abundant native herbaceous plant species (+bare soil) on soil functionality. We measured several soil functions (soil microbial biomass, metabolic quotient, and enzymatic activities – dehydrogenase, β-glucosidase and phosphatase) and built a soil multifunctionality index. Soil multifunctionality was strongly associated with mycorrhizal traits across the analysed SOM gradient. Bare soils and soils under non- or low-mycorrhizal plant species displayed the lower soil functionality (both individual functions and multifunctionality), while soils under Fabaceae species (Medicago truncatula, Astragalus corrugatus and Lotus halophilus) displayed the highest. For each plant species, the highest soil multifunctionality was observed at the SOM-richer site. Soil multifunctionality was strongly associated with all the mycorrhizal traits but mycorrhizal intensity and AMF spores abundance were more correlated with soil multifunctionality than mycorrhizal frequency. Our data show that: i) AM traits can be good indicators of simultaneous multiple soil functions in drylands; and ii) soil multifunctionality in drylands can be improved by management practices promoting SOM accumulation and favouring specific native plant species.