Undisturbed Sites Research Articles

Gradient of acid mine drainage regulates microbial community assembly and the diversity of species associated with native plants

Acid mine drainage (AMD) is considered as one of the most important global environmental challenges. Therefore, understanding the impact of AMD on the diversity of microbial communities associated with native plants is important for phytoremediation. In this study, the community assembly and microbial diversity associated with native plants growing along an AMD impact gradient was investigated using metabarcoding and high throughput iChip technique. The study revealed that across both domains of bacteria and fungi, richness and species diversity decreased according to AMD impact. Bacterial species diversity was more stratified according to the pH gradient than fungi, and the AMD impact on the plant-associated microbial diversity decreased towards the plant roots. The microbial community composition of the undisturbed site was significantly different from the AMD impacted sites, and the communities in the AMD impacted sites were further stratified according to the degree of impact. The overall microbial diversity was mediated by the AMD impact, niche differences and plant species differences. Dispersal limitation was the most important community assembly process in the undisturbed site, while the homogenous selection of Burkholderia, Actinospica, Puia and Bradyrhizobium increased along the AMD impact gradient. Differential abundance analysis further revealed that Umbelopsis, Burkholderia and Sphingomonas were among the biomarkers of the AMD impacted sites. Several strains of some of these responsive genera were subsequently isolated using the iChip. Overall, this study presents novel insight into the ecology of plant-associated microbial communities that are relevant for environmental monitoring and for enhancing the revegetation of AMD impacted sites.

Diversity of bacterial communities in wetlands of Calakmul Biosphere Reserve: a comparative analysis between conserved and semi-urbanized zones in pre-Mayan Train era

BackgroundThe Calakmul Biosphere Reserve (CBR) is known for its rich animal and plant biodiversity, yet its microbial communities remain largely unknown. The reserve does not possess permanent bodies of water; nevertheless, seasonal depressions associated with fractures create wetlands, known locally as aguadas. Given the recent construction of the Maya train that crosses the CRB, it is essential to assess the biodiversity of its microorganisms and recognize their potential as a valuable source of goods. This evaluation is pivotal in mitigating potential mismanagement of the forest ecosystem. To enhance comprehension of microbial communities, we characterized the microbiota in three different wetlands. Ag-UD1 and Ag-UD2 wetlands are located in a zone without human disturbances, while the third, Ag-SU3, is in a semi-urbanized zone. Sampling was carried out over three years (2017, 2018, and 2019), enabling the monitoring of spatiotemporal variations in bacterial community diversity. The characterization of microbiome composition was conducted using 16S rRNA metabarcoding. Concurrently, the genomic potential of select samples was examined through shotgun metagenomics.ResultsStatistical analysis of alpha and beta diversity indices showed significant differences among the bacterial communities found in undisturbed sites Ag-UD1 and Ag-UD2 compared to Ag-SU3. However, no significant differences were observed among sites belonging to the undisturbed area. Furthermore, a comparative analysis at the zone level reveals substantial divergence among the communities, indicating that the geographic location of the samples significantly influences these patterns. The bacterial communities in the CBR wetlands predominantly consist of genera from phyla Actinobacteria, Acidobacteria, and Proteobacteria.ConclusionThis characterization has identified the composition of microbial communities and provided the initial overview of the metabolic capacities of the microbiomes inhabiting the aguadas across diverse conservation zones. The three sites exhibit distinct microbial compositions, suggesting that variables such as chemical composition, natural and anthropogenic disturbances, vegetation, and fauna may play a pivotal role in determining the microbial structure of the aguadas. This study establishes a foundational baseline for evaluating the impact of climatic factors and human interventions on critical environments such as wetlands.

Effects of Wildfire and Logging on Soil CO2 Efflux in Scots Pine Forests of Siberia

Wildfires and logging play an important role in regulating soil carbon fluxes in forest ecosystems. In Siberia, large areas are disturbed by fires and logging annually. Climate change and increasing anthropogenic pressure have resulted in the expansion of disturbed areas in recent decades. However, few studies have focused on the effects of these disturbances on soil CO2 efflux in the vast Siberian areas. The objective of our research was to evaluate differences in CO2 efflux from soils to the atmosphere between undisturbed sites and sites affected by wildfire and logging in Scots pine forests of southern Siberia. We examined 35 plots (undisturbed forest, burned forest, logged plots, and logged and burned plots) on six study sites in the Angara region and four sites in the Zabaikal region. Soil CO2 efflux was measured using an LI-800 infrared gas analyzer. We found that both fire and logging significantly reduced soil efflux in the first years after a disturbance due to a reduction in vegetation biomass and consumption of the forest floor. We found a substantially lower CO2 efflux in forests burned by high-severity fires (74% less compared to undisturbed forests) than in forests burned by moderate-severity (60% less) and low-severity (37% less) fires. Clearcut logging resulted in 6–60% lower soil CO2 efflux at most study sites, while multiple disturbances (logging and fire) had 48–94% lower efflux. The soil efflux rate increased exponentially with increasing soil temperature in undisturbed Scots pine forests (p < 0.001) and on logged plots (p < 0.03), while an inverse relationship to soil temperature was observed in burned forests (p < 0.03). We also found a positive relationship (R = 0.60–0.83, p < 0.001) between ground cover depth and soil CO2 efflux across all the plots studied. Our results demonstrate the importance of disturbance factors in the assessment of regional and global carbon fluxes. The drastic changes in CO2 flux rates following fire and logging should be incorporated into carbon balance models to improve their reliability in a changing environment.

Effects of anthropogenic activities on the microbial community diversity of Ologe Lagoon sediment in Lagos State, Nigeria.

The impact of pollution on the Ologe Lagoon was assessed by comparing physicochemical properties, hydrocarbon concentrations and microbial community structures of the sediments obtained from distinct sites of the lagoon. The locations were the human activity site (OLHAS), industrial-contaminated sites (OLICS) and relatively undisturbed site (OLPS). The physicochemical properties, heavy metal concentrations and hydrocarbon profiles were determined using standard methods. The microbial community structures of the sediments were determined using shotgun next-generation sequencing (NGS), taxonomic profiling was performed using centrifuge and statistical analysis was done using statistical analysis for metagenomics profile (STAMP) and Microsoft Excel. The result showed acidic pH across all sampling points, while the nitrogen content at OLPS was low (7.44 ± 0.085mg/L) as compared with OLHAS (44.380 ± 0.962mg/L) and OLICS (59.485 ± 0.827mg/L). The levels of the cadmium, lead and nickel in the three sites were above the regulatory limits. The gas chromatography flame ionization detector (GC-FID) profile revealed hydrocarbon contaminations with nC14 tetradecane > alpha xylene > nC9 nonane > acenaphthylene more enriched at OLPS. Structurally, the sediments metagenomes consisted of 43 phyla,75 classes each, 165, 161, 166 orders, 986, 927 and 866 bacterial genera and 1476, 1129, 1327 species from OLHAS, OLICS and OLPS, respectively. The dominant phyla in the sediments were Proteobacteria, Firmicutes, Actinobacteria, and Chloroflexi. The principal component ordination (PCO) showed that OLPS microbial community had a total variance of 87.7% PCO1, setting it apart from OLHAS and OLICS. OLICS and OLHAS were separated by PCO2 accounting for 12.3% variation, and the most polluted site is the OLPS.

Land use effect on dominance of native and exotic earthworm species in two contrasting rural landscapes

Lumbricids and several species of the genus Amynthas have spread over all continents and seem to be better competitors than natives in disturbed ecosystems and agricultural fields. More than half of Uruguay's 19 earthworm species recorded by 2014 are exotic. Aiming to contribute to the scarce information on earthworm ecology in the region, the objectives of this work were 1) to characterize the earthworm communities in agriculture and natural ecosystems, and 2) to assess the relationship between land use and richness of native and exotic earthworm species. Related to the latter objective, we hypothesized that the difference in the number of exotic and native species depended on the degree of disturbance, and predicted that exotic species would dominate in more disturbed soils. We sampled organic and nonorganic agricultural fields including wheat in the rotations in the South and the North-West of Uruguay. Undisturbed sites, i.e. with no recent agriculture activity, close to each sampling plot served as controls. Analyses were conducted to elucidate whether other variables, besides disturbance and location, could be influencing earthworm community structure and composition. In both locations, exotic species dominated in control plots, i.e. less or non-disturbed land, and were associated to higher N, C and soil porosity. Moreover, in the North-West, natives would dominate in terms of richness in most agriculture plots. The mean body weight was larger in the South, where there were more exotic species, than in the North-West, where there were more native species. Thirteen of the collected species had been reported for Uruguay, the four other species found, were reported for the first time in this paper: Microscolex phosphoreus and Glossodrilus parecis (natives); and Aporrectodea tuberculata and Murchieona minuscula (exotics). Finding four unrecorded species evidences the poor coverage of earthworm sampling in anthropic and natural landscapes of the country.

Changes in vegetation composition and structure following landslide-induced disturbance in the Himalaya

The Himalaya cover 12% of India's landmass and are prone to approximately one-seventh of global rainfall-triggered landslides. Still, very few studies have examined the after-effects of landslides on native vegetation structure and composition. This study aims to fulfill this gap by analyzing the vegetation structure and composition of 10 landslide-impacted sites in Uttarakhand Himalaya along an elevational gradient between 1400–3500 m. The investigations revealed that physiognomically, the younger landslide-disturbed sites were dominated by herbaceous taxa while shrubs and trees dominated the older landslide-disturbed sites. Shannon–Wiener diversity values were highest at the old-low disturbed site compared with recent and young disturbed sites. Sorensen similarity index values indicated that the older landslide sites had the highest similarity in species composition of disturbed and undisturbed sites. The younger and recently disturbed landslide sites were highly dissimilar in species composition and structure as compared to the adjacent undisturbed sites. Notably, both the landslide-disturbed and undisturbed sites had a high percentage of native species (90%–95%). The fundamental understanding developed from this study can have potential applications in evolving management practices for ecological restoration of the degraded ecosystems in the Himalaya and other mountain ecosystems around the world.

Temporal asynchrony of plant and soil biota determines ecosystem multifunctional stability.

The role of plant biodiversity in stabilizing ecosystem multifunctionality has been extensively studied; however, the impact of soil biota biodiversity on ecosystem multifunctional stability, particularly under multiple environmental changes, remains unexplored. By conducting an experiment with environmental changes (adding water and nitrogen to a long-term grazing experiment) and an experiment without environmental changes (an undisturbed site) in semi-arid grasslands, our research revealed that environmental changes-induced changes in temporal stability of both above- and belowground multifunctionality were mainly impacted by plant and soil biota asynchrony, rather than by species diversity. Furthermore, changes in temporal stability of above- and belowground multifunctionality, under both experiments with and without environmental changes, were mainly associated with plant and soil biota asynchrony, respectively, suggesting that the temporal asynchrony of plant and soil biota has independent and non-substitutable effects on multifunctional stability. Our findings emphasize the importance of considering both above- and belowground biodiversity or functions when evaluating the stabilizing effects of biodiversity on ecosystem functions.

Exploring freshwater stream bacterial communities as indicators of land use intensity

BackgroundStream ecosystems comprise complex interactions among biological communities and their physicochemical surroundings, contributing to their overall ecological health. Despite this, many monitoring programs ignore changes in the bacterial communities that are the base of food webs in streams, often focusing on stream physicochemical assessments or macroinvertebrate community diversity instead. We used 16S rRNA gene sequencing to assess bacterial community compositions within 600 New Zealand stream biofilm samples from 204 sites within a 6-week period (February–March 2010). Sites were either dominated by indigenous forests, exotic plantation forests, horticulture, or pastoral grasslands in the upstream catchment. We sought to predict each site’s catchment land use and environmental conditions based on the composition of the stream bacterial communities.ResultsRandom forest modelling allowed us to use bacterial community composition to predict upstream catchment land use with 65% accuracy; urban sites were correctly assigned 90% of the time. Despite the variation inherent when sampling across a ~ 1000-km distance, bacterial community data could correctly differentiate undisturbed sites, grouped by their dominant environmental properties, with 75% accuracy. The positive correlations between actual values and those predicted by the models built using the stream biofilm bacterial data ranged from weak (average log N concentration in the stream water, R2 = 0.02) to strong (annual mean air temperature, R2 = 0.69).ConclusionsFreshwater bacterial community data provide useful insights into land use impacts on stream ecosystems; they may be used as an additional measure to screen stream catchment attributes.

Oil and gas development influences potential for dust emission from the Upper Colorado River Basin, USA

AbstractWind erosion and dust emission from drylands have large consequences for ecosystem function and human health. Wind erosion is naturally reduced by soil crusting and sheltering by non‐erodible roughness elements such as plants. Land uses that reduce surface roughness and disturb the soil surface can dramatically increase dust emission. Extraction of oil and gas is a common and growing land use in the western United States (US) that removes vegetation and other roughness elements for construction of well pads and unpaved access roads, resulting in thousands of small (1–4 ha), discrete patches of unprotected soil. Here, we use a satellite albedo‐based model to assess the effect of oil/gas activity on surface roughness in the Uinta‐Piceance Basin, an area of the Upper Colorado River Basin (UCRB) with dense oil and natural gas development and modelled how the change in surface roughness could impact aeolian sediment flux and dust emission. We also investigated how regional drought influences the response of surface roughness to well pads and access roads. Oil/gas activity reduced surface roughness and increased modelled aeolian sediment flux at the landscape scale across much of the study region, resulting in a modest increase of 10 139 kg of dust per year, which is small relative to dust loads from a single regional dust event observed in the region, but downwind impact could be significant. The magnitude of surface roughness reductions by oil/gas activity was generally consistent among land cover types. However, in parts of the basin that had high cover of annual forbs and grasses, oil/gas activity was associated with larger surface roughness and smaller potential dust emission. Drought decreased surface roughness across disturbed and undisturbed sites, but there was no interactive effect of oil/gas activity and drought on surface roughness. These results suggest that oil/gas activity may increase sediment fluxes and likely contributes to dust emission from landscapes in the UCRB. Understanding how drought and land use change contribute to dust emissions will benefit mitigation of undesirable impacts of wind erosion and dust transport.

Flowering Plant Diversity of Differentially Disturbed Region of Terai Sal (Shorea robusta) Forest in Eastern Nepal

Terai Sal (Shorea robusta C.F.Gaertn.) forest, characteristic forest of lowland of Nepal, faces direct and indirect impacts from various anthropogenic activities. The present work aimed to study and document the flowering plant diversity within differentially disturbed sites of Charali Sal forest. Additionally, we accessed the habitat condition, analyzed the invasion status and prioritize the threats faced by the plant communities and recommended ways to mitigate the prevalent threats. We employed purposive sampling technique to sample the forest areas and nested plot design for vegetation sampling. Thirty sample plots, each measuring 10 m × 10 m, were established on two differentially disturbed sites (disturbed and undisturbed) of Charali Sal forest. A total of 111 flowering plant species belonging to 39 families were documented in the sampling sites, with 90 total species (89 identified) in disturbed sites and 86 species (80 identified) in undisturbed sites. Although the disturbed sites contained higher number of flowering plants, the diversity indices (Simpson and Shannon-wiener’s) indicated higher diversity on undisturbed site. Disturbed site exhibited higher human encroachment and higher invasion of alien species compared to undisturbed site. Specific habitat management plans should be devised for the control and eradication of invasive species from the Charali Sal forest. We highly recommend to delimit a buffer zone all around the forest perimeter to regulate local access inside the forest. Collecting and harvesting various forest products should be restricted to the buffer zone, while the inner forest areas should be under careful and strict management. Implementing these strict managemental strategies would be challenging, but it is crucial for preserving the natural integrity of the forest.

PHYSICAL PROPERTIES OF UPPER MINERAL HORIZONS OF CUTTING AREA (MIDDLE TAIGA, KOMI REPUBLIC)

Changes in the physical properties of podzolic soils were analysed three years after a cutting of coniferous-deciduous plantings in the territory of the middle taiga of the Komi Republic with three- and ten-fold forwarder passes, as well as after leveling deep ruts formed after ten passes. The influence of different number of passes on soil density, filtration coefficient, penetration resistance is shown. An assumption about various mechanisms of soil change has been made: three forwarder passes lead to compression, ten - to compression and turbation, which was confirmed by indications of soil density and hardness. It was revealed that compression leads to an increase in density by 0.15 g·cm-3 and penetration resistance by 25%. Meanwhile, filtration rate did not change. Ten passes lead to turbation, which levels the possible compaction due to an introduction of forest litter into the upper mineral soil horizons. Moreover, hardness values decreased by 2-3 times and water permeability decreased from 70 to 1 cm·day-1. It was revealed that leveling deep ruts causes a noticeable decrease in soil density after three years, including in comparison with the undisturbed soil. Furthermore, filtration rate increases several times. Penetration resistance is also increased. An estimation of the water retention curve approximation parameters by the van Genuchten equation made it possible to identify changes in soil of ruts compared to the a mechanically undisturbed site. A decrease in the range of mobile moisture was noted as a result of compaction after heavy equipment usage, leading to moisture stagnation in ruts.

Effects of banqueting on water infiltration and physico-chemical properties of soil in semi-arid lands

Banqueting is a simple and cheap soil conservation practice in natural rangelands under dry climates. Little research exists about its impacts compared to other land uses, where agriculture and land abandonment may be important reasons for degradation. This study has evaluated water infiltration and key physico-chemical properties of soil in natural rangelands with banquets in West Azerbaijan (North-Western Iran) compared to: (i) undisturbed sites (assumed as reference condition) and (ii) cultivated or abandoned dry farmlands. Under these soil conditions, the texture, bulk density, porosity, water content, pH, electrical conductivity, organic carbon and carbonate contents of soil (using common physical-chemical methods) as well as the hydraulic conductivity (using a single-cylinder infiltrometer) were measured in the topsoil (0–20 cm). This data was further processed by applying the Principal Component Analysis and the Agglomerative Hierarchical Cluster Analysis. In areas with banquets, soil hydraulic conductivity was higher by 84% compared to dry farmlands (abandoned or not), where water infiltration was noticeably reduced (−44%) compared to the reference soil condition. Moreover, a noticeable increase in organic carbon content (+80%) and a lower salinity (−36%) of soil compared to cultivated areas was measured. These effects are important to enhance soil fertility on one side, and resistance to erosion on the other side. Therefore, in the experimental areas, banqueting may counteract the degradation of soil due to the agricultural activity as well as its abandonment, and restore the properties of the undisturbed soils that are typical of natural rangelands. The results of this study may be of help for landscape managers and agronomists for the pressing needs for soil conservation and productivity in semi-arid areas that are prone to degradation and abandonment.

The demise of enemy release associated with the invasion of specialist folivores on an invasive tree

There is a long history of humans either intentionally or accidentally moving plant species to areas outside of their native ranges. In novel environments, populations of many of these plant species exhibit explosive population growth and spread, in part due to the absence of coevolved enemies such as herbivorous insects. However, over time such enemies can ‘catch up' with their host and re‐establish host–herbivore relationships. Though this phenomenon has been documented in several systems, little evidence exists on how this re‐assembly of enemies results in increased levels of herbivory. In this study we focus on the case of black locust Robinia pseudoacacia, a sparsely populated tree species when growing on undisturbed sites in its limited native range in the eastern USA but a highly invasive species, especially in disturbed environments, in most temperate world regions. We recorded folivore damage on invasive populations in five continents, including both native and invaded portions of North America. Here, we investigated 1) how total foliage damage and damage caused by different groups of folivores differs among regions; 2) how seasonal development of folivore damage differs among regions; 3) how folivory varies with distance from the native range within North America; and 4) how the number of recorded specialist folivores correlates with the amount of folivory. We observed strong differences among regions in the amount and type of folivore damage, with the native range experiencing the highest damage, especially that caused by the native chrysomelid beetle Odontota dorsalis, which is limited to the native and invaded North American range of R. pseudoacacia. Among world regions, total folivory is negatively associated with the distance from the native range and positively associated with the number of established R. pseudoacacia specialist folivore species, supporting the hypothesis that global patterns of herbivore invasions are associated with diminished enemy release.

Host sweet host: Rodent communities support similar ectoparasite diversity regardless of anthropogenic disturbance

AbstractRodents are important hosts for ectoparasites, such as fleas, ticks, and mites, which means they are also important intermediate hosts for many zoonotic diseases. As anthropogenic environments bring humans and rodents into closer contact, an understanding of host–ectoparasite ecology is essential to predict and manage disease spillover risks. We aimed to understand how disturbances in vegetation cover affect rodent ectoparasite diversity, prevalence, spatial segregation, host (i.e., sex, genus, size, and habitat domain), and environmental (i.e., vegetation structure, forest cover, and rainfall) variables in the state of Michoacan, Mexico. We investigated these relationships by trapping rodents in five paired disturbed (reduced vegetation cover and regular human activities) and undisturbed (no reduction in vegetation cover) sites in the summer and autumn of 2022. From 110 trapped rodents, we collected 138 ectoparasites on 38 individuals. We found no difference in rodent diversity, ectoparasite diversity, or ectoparasite prevalence between disturbed and undisturbed sites. However, arboreal and male rodents had a higher probability of carrying ectoparasites than ground‐dwelling and female rodents. Rodents with ectoparasites were not spatially clustered; rather, they were randomly distributed across trapping grids. We also identified two rodent genera (Rattus and Sigmodon) that carry ectoparasites of medical importance and that are in close contact with humans. Our results highlight the necessity of constant monitoring of rodents, ectoparasites, and their associated transmittable diseases. Assessing these interactions and how they are affected by anthropogenic disturbance could better inform management decisions and support the need for rodent conservation programmes in the area.

Soil heavy metal pollution and ecological risk assessment in disturbed and undisturbed soil of Morigaon, Assam

Soil heavy metal pollution and ecological risk assessment in disturbed and undisturbed soil of Morigaon, Assam

Effects of grazing on soil properties in mediterranean forests (Central-Eastern Spain)

Traditional management practices, such as grazing, can have adverse impact on soils. Despite an extensive body of literature exploring the effects of grazing on soil and plants worldwide, there is a notable lack of research on its impacts in Mediterranean forests within the Iberian Peninsula Furthermore, there is a knowledge gap on the enzymatic activities and basal respiration of soil in forest after grazing. To address these gaps, this study aimed to investigate the impact of grazing on various important physicochemical and biological soil properties along with vegetation richness in a Mediterranean forest located in Castilla-La Mancha (Central Eastern Spain). Relative to undisturbed sites, grazing significantly reduced soil water content (−53%) and available water (−59%). However, soil hydraulic conductivity remained unaffected by animal trampling and the soil water repellency observed in ungrazed sites disappeared. Grazed soils experienced a slight increase in pH (+18%). Among the biochemical properties studied, only dehydrogenase showed a significant increase (+100%) while basal respiration exhibited a notable decrease (−24%). Grazing resulted in a reduction of plant species richness (−34%) indicating a loss of biodiversity in grazed areas. The observed significant alterations in key soil and plant properties due to livestock activity suggest that grazing has the potential to modify the overall soil quality of these sites. Certain variables that exhibited noteworthy differences between grazed and ungrazed sites could serve as indicators of grazing impacts in Mediterranean forests. These indicators may be considered proxies for establishing effective land management strategies to mitigate degradation in the Mediterranean forest ecosystem.

Microbial composition and function in reclaimed mine sites along a reclamation chronosequence become increasingly similar to undisturbed reference sites

Mine reclamation historically focuses on enhancing plant coverage to improve below and aboveground ecology. However, there is a great need to study the role of soil microorganisms in mine reclamation, particularly long-term studies that track the succession of microbial communities. Here, we investigate the trajectory of microbial communities of mining sites reclaimed between three and 26 years. We used high-throughput amplicon sequencing to characterize the bacterial and fungal communities. We quantified how similar the reclaimed sites were to unmined, undisturbed reference sites and explored the trajectory of microbial communities along the reclamation chronosequence. We also examined the ecological processes that shape the assembly of bacterial communities. Finally, we investigated the functional potential of the microbial communities through metagenomic sequencing. Our results reveal that the reclamation age significantly impacted the community compositions of bacterial and fungal communities. As the reclamation age increases, bacterial and fungal communities become similar to the unmined, undisturbed reference site, suggesting a favorable succession in microbial communities. The bacterial community assembly was also significantly impacted by reclamation age and was primarily driven by stochastic processes, indicating a lesser influence of environmental properties on the bacterial community. Furthermore, our read-based metagenomic analysis showed that the microbial communities' functional potential increasingly became similar to the reference sites. Additionally, we found that the plant richness increased with the reclamation age. Overall, our study shows that both above- and belowground ecological properties of reclaimed mine sites trend towards undisturbed sites with increasing reclamation age. Further, it demonstrates the importance of microbial genomics in tracking the trajectory of ecosystem reclamation.

Bioindication for Ecosystem Regeneration towards Natural conditions: the BERN data base and BERN model

The primary task of the BERN database is to document reference data on typical site parameters for the occurrence of plant communities in which their diagnostic species are in competitive equilibrium with each other and in homeostatic equilibrium with the site factors. Common approaches for the creation of a site-plant database such as ordination or bioindication based on individual species like PROPS or MultiMOVE model are of limited use because it is not possible to determine the potential occurrence of a plant species on the basis of site factors, since the competitive influences cannot be determined in advance according to current knowledge. Therefore, the BERN database takes into account the structure of plant communities with the abundance and dominance of species in the competitive equilibrium of plant communities as a reference for determining anthropogenically induced changes. Qualitative knowledge on the relationship between site types and vegetation communities is widely available, as can be seen from the extensive phytosociological publications. For this purpose, synoptic tables and their location descriptions of around 50,000 relevés were evaluated. The BERN database includes currently 887 central European plant communities and links to their diagnostically defining species composition. The database defines the niche of 2210 central European plant species for the soil properties pH, base saturation, carbon to nitrogen ratio, and wetness index and the climatic properties continentality, length of vegetation period, solar radiation and climatic water balance. The BERN model recombines the realised species niches that mainly form the competitively homeostatic structure of a plant community in order to determine the fundamental multifactorial niche of this community. The BERN database contains mainly historical recordings of more or less undisturbed sites. The BERN model (Bioindication for Ecosystem Regeneration towards Natural conditions) as an application module of the BERN database was developed to integrate ecological cause-effect relationships into studies on environmental status assessment and forecasting. The BERN database now has been published for the first time. The methodology of creating the BERN database and the BERN model are documented and applications are demonstrated with examples. The freely available database should invite you to supplement and modify it.

Estimating Effective Hydraulic Conductivity (Ke) for the Rangeland Hydrology and Erosion Model (RHEM)

Highlights Effective hydraulic conductivity (Ke ) predictive equations in all RHEM versions have satisfactory performance. New Ke predictive equations were developed for RHEM applications over broader rangeland conditions. Ke values on most rangelands can be estimated through readily measurable ground cover and soil texture data. Abstract. Effective hydraulic conductivity (Ke) is an important parameter for the prediction of infiltration and runoff by the Rangeland Hydrology and Erosion Model (RHEM). Three sets of equations to predict Ke have previously been used in RHEM. These equations are mainly based on rainfall simulation data representing undisturbed sites and have not undergone comprehensive evaluation for various rangeland conditions, particularly after disturbances. The goal of this research was to evaluate these equations using independent data obtained from rainfall simulations conducted at multiple rangeland sites. Additionally, we developed and evaluated a new set of Ke predictive equations applying readily measurable cover and soils data spanning a wide range of vegetation, soil textures, and disturbance conditions. The results show that all previous Ke equations in RHEM have a “satisfactory” performance with index of agreement (d) > 0.75 and R2 > 0.4. The new Ke approach resulted in “very good” performance with d > 0.9 and R2 > 0.5. The new set of equations enhances RHEM for applications over broader rangeland conditions, including sparse vegetation cover following disturbances or community transitions. Keywords: Disturbed Rangelands, Hillslope Runoff, Infiltration.

Accelerated anti-oxidant enzymes and phytochemical potential of Taxus wallichiana (Himalayan yew) under moist temperate forest of Himalayan, Pakistan

Abstract Taxus wallichiana (Himalayan yew) antioxidant potential enhances the release of secondary metabolites and enzymes under stress; over the last few decades owing to changes in climatic regimes, such species are under constant threat in the moist temperate Himalayan forests. The present study aims to evaluate the effect of change in land-use pattern on the antioxidant and phytochemical potential of T. wallichiana (Himalayan yew) in the moist temperate Himalayan Forest of Galiyat-Khyber-Pakhtunkhwa-Pakistan. Three leaf samples from each location of T.W were collected from high (Ayubiya, 2,970 m.a.s.l.) undisturbed, disturbed mid (Baragali, Dongagali, Kuldana, Chegagali, 2,617, 2,375, 2,455, 2,804 m.a.s.l.) and low (Murree, 2,000 m.a.s.l.) altitudes of moist temperate forest of Galiayt-Himalayan-Khyber-Pakhtunkhwa-Pakistan, DPPH assay, total flavonoids and phenolic content, total protein and proline content, catalase, superoxide dismutase and peroxidase activities were analysed. The antioxidant activity (DPPH) response was more pronounced in low and mid altitude disturbed sites than the undisturbed site at high altitudes. Antioxidant enzymes and osmolyte content further supported the stress tolerance capacity of T. wallichiana to scavenge the ROS produced under oxidative stress conditions. In conclusion, Taxus wallichiana inhabiting in these sites could withstand long durations of drought, salinity, frost, high temperatures, and pathogenic attacks by activating the antioxidant enzymes.