Plant Indicator Species Research Articles

Assessment of Herbaceous Plant Composition, Diversity, and Indicator Species in the Juniperus drupacea Forest Openings of the Mountain Parnonas in Greece

A significant challenge in community ecology is the establishment of ecological baselines, which permit the evaluation of the variations in ecological dynamics at different temporal and spatial scales. To our best knowledge, few studies have been conducted in the forest openings of Mt. Parnon to establish a baseline for future monitoring. Hence, a floristic study of the herbaceous plant species composition, diversity, cover, and biomass was conducted in the forest openings of the Mt. Parnon-Natura 2000 Site in Greece to develop an ecological baseline that could be utilized in decision making for conservation and the sustainable use of forest biodiversity and ecosystem services in the forest ecosystem of Mt. Parnon. In the spring season, a thorough floristic survey was performed on Mt. Parnon for two consecutive years, 2021 and 2022. Herbaceous plant composition, diversity, cover, biomass, and plant indicator species (indicator value analysis) in the forest openings of Mt. Parnon were assessed. In the studied area, 63 plant species belonging to 58 genera from 20 families were recorded. The most numerous families were Asteraceae and Poaceae, followed by Fabaceae. Variable plant diversity, herbaceous plant cover, and produced biomass were recorded in different sites. It is noteworthy that some plant species could be regarded as indicators of the sites in the study area [Geranium molle L., Cerastium candidissimum Correns, Vicia villosa Roth, Euphorbia myrsinites L., Odontarrhena muralis (Waldst. & Kit.) Endl., Medicago lupulina L., Lotus corniculatus L., Crepis fraasii Sch. Bip., Bellis sylvestris Cirillo, and Trifolium stellatum L.], and information about these indicators, including Ellenberg type indicator values, is also provided. This study contributes to the understanding of the relevant ecological topics and provides key elements that could be utilized in decision making for the conservation and sustainable use of forest biodiversity and ecosystem services on Mt. Parnon.

A Multi-Community Approach in Biodiversity Assessment of a Peat Bog in the Southern Carpathians (Romania) and Implications for Conservation.

Although natural peatlands have been recognized as an important type of wetlands because they support high biodiversity and provide important ecosystem services, the value of peatlands both in biodiversity research and conservation is still largely underestimated. Our study characterizes the biodiversity and conservation value of Peşteana peat bog, an upland mesotrophic peat bog, located in the Southern Carpathians, Romania. More specifically, we: (1) characterized the invertebrate (i.e., top soil, surface litter, and plant-dwelling) and plant communities along a humidity gradient in Peşteana peat bog and nearby habitats (i.e., treeline, ecotone, lowland and highland meadow, and forest), (2) assessed the main environmental factors driving the invertebrate community diversity and composition, and (3) determined the relationship between invertebrate community diversity and vegetation, focusing on the top soil invertebrates. Our study revealed a high diversity of invertebrates spanning over 43 taxonomic groups and a high number of plant indicator species, emphasizing the role of natural peatlands in preserving diverse communities in a small area. The results showed that the composition of top soil invertebrate community was determined by depth of organic layer, vegetation cover, and soil compaction. We found that the diversity of top soil invertebrate community was strongly influenced by habitat type and soil attributes and weakly by vegetation. Overall, the invertebrate and plant communities showed different responses to habitat conditions along the humidity gradient. This highlights the importance of using a multi-community approach to support the design of effective conservation and management actions beneficial for a wide range of taxa.

Soil properties and plant species can predict population size and potential introduction sites of the endangered orchid Cypripedium calceolus

Background and AimsTo counteract the ongoing worldwide biodiversity loss, conservation actions are required to re-establish populations of threatened species. Two key factors predominantly involved in finding the most suitable habitats for endangered plant species are the surrounding plant community composition and the physicochemical parameters of the soil rooting zone. However, such factors are likely to be context- and species-dependent, so it remains unclear to what extent they influence the performance of target species.MethodsWe studied large and small Swiss populations of the endangered orchid Cypripedium calceolus. We measured functional traits related to C. calceolus plant and population performance (clonal patch area, plant height, number, of leaf, stems, flowers and fruits), realized vegetation surveys, soil profile analyses, and tested for relationships between plant traits and the surrounding vegetation structure or soil physicochemical parameters.ResultsLarge populations contained bigger patches with more stems and leaves, and produced more flower per individual than small populations. Neither vegetation alliances nor soil classes per se could predict C. calceolus functional traits and population size. However, functional traits explaining population performance and size were related to specific soil parameters (soil organic matter content, pH and phosphorus), in addition to a combination of presence-absence of plant indicator species, relating to ecotones between forests and clearings.ConclusionWe show that even for species that can grow across a wide range of vegetation groups both indicator species and specific soil parameters can be used to assess the most favourable sites to implement (re)-introduction actions.

Scrub encroachment promotes biodiversity in temperate European wetlands under eutrophic conditions.

Wetlands are important habitats, often threatened by drainage, eutrophication, and suppression of grazing. In many countries, considerable resources are spent combatting scrub encroachment. Here, we hypothesize that encroachment may benefit biodiversity-especially under eutrophic conditions where asymmetric competition among plants compromises conservation targets. We studied the effects of scrub cover, nutrient levels, and soil moisture on the richness of vascular plants, bryophytes, soil fungi, and microbes in open and overgrown wetlands. We also tested the effect of encroachment, eutrophication, and soil moisture on indicators of conservation value (red-listed species, indicator species, and uniqueness). Plant and bryophyte species richness peaked at low soil fertility, whereas soil fertility promoted soil microbes. Soil fungi responded negatively to increasing soil moisture. Lidar-derived variables reflecting the degree of scrub cover had predominantly positive effects on species richness measures. Conservation value indicators had a negative relationship to soil fertility and a positive to encroachment. For plant indicator species, the negative effect of high nutrient levels was offset by encroachment, supporting our hypothesis of competitive release under shade. The positive effect of soil moisture on indicator species was strong in open habitats only. Nutrient-poor mires and meadows host many rare species and require conservation management by grazing and natural hydrology. On former agricultural lands, where restoration of infertile conditions is unfeasible, we recommend rewilding with opportunities for encroachment toward semi-open willow scrub and swamp forest, with the prospect of high species richness in bryophytes, fungi, and soil microbes and competitive release in the herb layer.

Infertile and Less Infertile Forest Types in the Ukrainian Carpathians: Classification and Complementation

Forest typology is yet to get sufficiently integrated into related ecological and geographical sciences. The succession of plant phytocenoses necessitates constant adjustments to forest types. The discussed studies have been conducted to improve the classification of forest types in the Ukrainian Carpathians and bring the description closer to the actual distribution of vegetation within the studied area. The paper provides a detailed analysis of forest typology research for the Ukrainian Carpathians area during late 20th and early 21st century. The forest fund areas of the Carpathian region, which are subordinated to the State Agency of Forest Resources of Ukraine, have been classified by forest vegetation types. Total area of subor and coniferous forest types is 1,493.1 ha and 28,910.2 ha, respectively. The study involved establishing of permanent sample plots on the territory of nature protection institutions and forest management enterprises. According to the findings, it is proposed to complement the classification of subor and coniferous forest type as defined by Z.Yu. Herushynskyi on the territory of the Ukrainian Carpathians with the following types: fresh pine subor forest type, wet pine subor forest type, and wet pine coniferous type. The paper defines the main diagnostic features of the suggested forest types. These subor and coniferous forest types can be clearly distinguished from other forest types by soil and hydrological conditions, and can be used to describe the corresponding forest vegetation types. The correctness of definition of new forest types is confirmed with a set of plant indicator species that have been identified within the relevant areas. The findings provide a better understanding of forest ecology and make a significant contribution to forest typology studies on the territory of the Ukrainian Carpathians. Another step towards researching the patterns of the establishment of plant complexes in the Ukrainian Carpathians has been taken. Forest formations of the Carpathians are presented in more detail in forest typological science

Plants predict the mineral mines – A methodological approach to use indicator plant species for the discovery of mining sites

IntroductionThere has been limited research conducted on the identifications/methodological approaches of using plant species as indicators of the presence of economically, important mineral resources. ObjectivesThis study set out to answer the following questions (1) Do specific plant species and species assemblages indicate the presence of mineral deposits? and (2) if yes, then what sort of ecological, experimental, and statistical procedures could be employed to identify such indicators? MethodsKeeping in mind these questions, the vegetation of subtropical mineral mines sites in northern Pakistan were evaluated using Indicator Species Analysis (ISA), Canonical Correspondence Analysis (CCA) and Structural Equation Modeling (SEM). ResultsA total of 105 plant species belonging to 95 genera and 43 families were recorded from the three mining regions. CA and TWCA classified all the stations and plants into three major mining zones, corresponding to the presence of marble, coal, and chromite, based on Jaccard distance and Ward’s linkage methods. This comprehended the following indicator species: Ficuscarica, Isodonrugosus and Ajugaparviflora (marble indicators); Oleaferruginea, Gymnosporiaroyleana and Diclipterabupleuroides (coal indicators); and Acacianilotica, Rhazyastricta and Aristidaadscensionis (chromite indicators) based on calculated Indicator Values (IV). These indicators were reconfirmed by CCA and SEM analysis. ConclusionIt was concluded that ISA is one of the best techniques for the identification/selection of plant indicator species, followed by reconfirmation via CCA and SEM analysis. In addition to establishing a robust approach to identifying plant indicator species, our results could have application in mineral prospecting and detection.

Impacts of management at a local and landscape scale on pollinators in semi‐natural grasslands

Abstract Managing farmland to benefit biodiversity is becoming increasingly necessary to combat biodiversity declines and maintain ecosystem services. Results‐based agri‐environmental schemes are a tool used to achieve this by paying farmers based on environmental results delivered. These schemes often utilise plant indicator species to assess results at field scale; however, it is unknown if focusing on enhancing a subset of one biodiversity group within results‐based schemes impacts wider biodiversity, and whether local‐scale implementation of results‐based schemes or/and the wider landscape are more important drivers of biodiversity patterns. Insect pollinators provide important pollination services for many crop and wild plants, and as mobile organisms often experience landscape at large spatial scales. We tested whether insect pollinators are affected at local scale by a results‐based scheme scored based on plant indicators, or if landscape management is more important, and whether there were different responses between taxon‐specific groups. Bumblebees, solitary bees, hoverflies and butterflies were sampled using transects and pan traps in 23 fields with varying scores assigned by the scheme, situated in high‐intensity (≥65% improved grassland) or low‐intensity (≥65% semi‐natural grassland) landscapes. Results indicate taxon‐specific responses to local and landscape management in semi‐natural grasslands. Bumblebees responded positively to local‐scale management in fields with higher floral diversity, whereas hoverflies and butterflies responded positively to low‐intensity landscape management. Synthesis and applications. Using plant species as indicators for biodiversity in agri‐environment schemes can have indirect benefits for non‐target taxa like bumblebees, but broader indicators should be developed to incorporate other pollinator groups. Pollinator groups respond differently to local and landscape management in semi‐natural grasslands. Agri‐environmental management should consider a range of different management measures and landscape scale approaches where possible, to maximise benefits for a range of pollinator taxa.

Selecting appropriate plant indicator species for Result-Based Agri-Environment Payments schemes

Agri-Environment Schemes (AES) have long been implemented across Europe to incentivise farmers to alter their management practices to improve biodiversity and water, air and soil quality. However, the cost-effectiveness of traditional action-based schemes has been questioned, and Result-Based Payment (RBP) schemes have been recommended as an alternative. To evaluate the effectiveness of management actions, RBP approaches often rely on indicator species to monitor changes in environmental conditions. The selection of appropriate indicator species for RBP follows several steps and criteria. One of the mentioned criteria is that the species should react to the farmer’s management choices. Thus, the main objective of this study is to understand how existing lists of indicator plant species (aimed at assessing ecological integrity of grasslands and hedgerows in Ireland) are suitable for RBP schemes, by assessing how different environmental and management variables are related to the presence of the plant species selected. Extensive field surveys were conducted to assess the presence and cover of indicator species in grasslands and hedgerows in two study regions in Ireland. The indicator plant species occurrence and diversity (species richness and Simpson’s Diversity Index) were correlated with variables within farmers’ control and variables outside farmers’ control. Results showed that grassland indicator species occurrence and diversity was mainly related to grassland semi-naturalness and to the diversity of habitats existing on the farm – both variables within farmers’ control – and thus were appropriate indicators for assessing the effectiveness of management and suitable for use in RBP schemes. Conversely, the occurrence and diversity of hedgerow indicator species was not strongly related to any of the explanatory variables, making them unsuitable for use in a RBP scheme. For a RBP scheme targeted at hedgerows, clear objectives will need to be established and the farmers’ management choices need to be better linked to the selected indicator species. The selection of indicator species needs to undergo scientific scrutiny to develop fair results assessments as shown by the results of this study. The analyses conducted highlight the importance of testing if the species react to the farmers’ management choices and should be a key methodological step before final indicator species lists are implemented in RBP schemes. Recommendations for results assessments in RBP approaches are discussed based on the results of this study.

Roads, railways, and power lines: Are they crucial for bees in urban woodlands?

The loss and transformation of habitats due to human impact are commonly regarded as major factors decreasing the diversity of pollinators. However, there is also some evidence that industrial infrastructure can play a positive role in shaping the composition of many animal communities. Still, little is known about how artificial linear structures, such as roads, railways, and electric power lines, affect the abundance and diversity of wild bees in urban ecosystems. Thus, we attempted to verify which of the habitats mentioned above is crucial for the occurrence of bee species of various functional groups. We conducted field research in woodlands of the city of Bydgoszcz (northern Poland). Site conditions were evaluated on the basis of phytoindicators (plant indicator species). In the study area, we recorded 32 % of all bee species reported from Poland. In respect of species richness and abundance, the habitats along railway lines were the most attractive to bees. Besides, in respect to bee species richness, these sites were the most similar to roadsides. The habitats located under power lines were the poorest in species. About 20 % of bee species were recorded only along railways and 3 % only along roads, while no bee species was recorded exclusively under power lines. Bee species richness and abundance increased with growing cover of the sites by bee food plants and an increasing proportion of bare soil. Moreover, bee abundance increased with an increasing share of plant indicator species of very dry or dry soils and of alkaline soils. Bee abundance declined with an increasing share of plant indicator species of sandy soils. The presented results indicate that roads, railway lines, and power lines, in structurally simplified and floristically poor pine forests, are important for wild bees in urban ecosystems.

Plant indicator species for the conservation of priority forest in an insular forestry area, Yambaru, Okinawa Island

ABSTRACT Degradation of old-growth forests is an important issue for global biodiversity conservation. Robust indicator species greatly facilitate the identification of old-growth forests requiring protection. Understanding why particular species are associated with priority forests is necessary for assessing the reliability of indicator species. Here, we surveyed the vegetation of 69 sites in Yambaru forests (Okinawa Island) varying in forest age and analyzed the relationships between the dominance of vascular species and three criterion parameters (forest age and species richness (SR) of epiphytes and endangered plants). Eleven species showing significant positive correlations with three parameters were designated as potential candidate indicator species, ten of which were woody species. Of the above eleven candidate indicator species, Distylium racemosum was considered one of the most useful indicator species because it can be easily identified in the field and its ecological characteristics are well documented. Regarding three woody traits – sprouting ability, annual growth rate and wood density – which are expected as the cause of indexing, endangered SR increased when tree species with low sprouting ability and high wood density were dominant, and epiphyte SR increased when tree species with low annual growth rate and high wood density were dominant. These woody species traits were associated with forest age and could explain why D. racemosum is an indicator of priority forest. These results suggest that large trees with such woody characteristics are effective indicators of priority forests.

Prolonged interglacial warmth during the Last Glacial in northern Europe

Few fossil‐based environmental and climate records in northern Europe are dated to Marine Isotope Stage (MIS) 5a around 80 ka BP. We here present multiple environmental and climate proxies obtained from a lake sequence of MIS 5a age in the Sokli basin (northern Finland). Pollen/spores, plant macrofossils, NPPs (e.g. green algae), bryozoa, diatoms and chironomids allowed an exceptionally detailed reconstruction of aquatic and telmatic ecosystem successions related to the development of the Sokli Ice Lake and subsequent infilling of a relatively small and shallow lake confined to the Sokli basin. A regional vegetation development typical for the early half of an interglacial is recorded by the pollen, stomata and plant macrofossil data. Reconstructions of July temperatures based on pollen assemblages suffer from a large contribution of local pollen from the lake's littoral zone. Summer temperatures reaching present‐day values, inferred for the upper part of the lake sequence, however, agree with the establishment of pine‐dominated boreal forest indicated by the plant fossil data. Habitat preferences also influence the climate record based on chironomids. Nevertheless, the climate optima of the predominant intermediate‐ to warm‐water chironomid taxa suggest July temperatures exceeding present‐day values by up to several degrees, in line with climate inferences from a variety of aquatic and wetland plant indicator species. The disequilibrium between regional vegetation development and warm, insolation‐forced summers is also reported for Early Holocene records from northern Fennoscandia. The MIS 5a sequence is the last remaining fossil‐bearing deposit in the late Quaternary basin infill at Sokli to be studied using multi‐proxy evidence. A unique detailed climate record for MIS 5 is now available for formerly glaciated northern Europe. Our studies indicate that interglacial conditions persisted into MIS 5a, in agreement with data for large parts of the European mainland, shortening the Last Glacial by some 50 ka to MIS 4‐2.

Interactive disturbances drive community composition, heterogeneity, and the niches of invasive exotic plant species during secondary succession

ABSTRACT Background Simultaneous disturbances during secondary succession can cause plant community shifts, facilitating exotic species invasions. However, it remains unclear if exotic invasion is facilitated by additive or interactive disturbance effects during succession. Aims Our aim was to investigate temporal shifts in plant species composition, invasive exotics, and indicator species during simultaneous disturbances in secondary succession. Methods We used species data from nine plant surveys over 22 years of a field experiment in an old field where parallel strips were randomly assigned to each of the 9 crossed fertiliser and mowing disturbance treatments. Multivariate and ordination analyses were used to quantify community response to disturbance. Indicator species analysis identified plants characteristic of different disturbance levels. Results Plant communities differed in composition and heterogeneity based on interactive effects of disturbance treatments whereas pairwise tests showed these differences occurred in over two-thirds of treatment combinations. Of the 44 indicator plant species, seven of the eight exotic species of concern for Illinois were indicator species and characterised particular disturbance treatments and surveys. Conclusions Changes in these successional plant communities depend on the interaction among disturbances, which can facilitate exotic plant invasions, leading to plant communities which disproportionately maintain invasive exotic plants as compared to other naturalised exotic and native plant species.

Subfossil oribatid mite communities indicate Holocene permafrost dynamics in Canadian mires

Permafrost thaw in peatlands is one of the most widespread and worrying consequences of climate warming in the sub‐Arctic area. To predict future climate feedbacks, it is important to study the history of permafrost aggradation and thaw. Plant macrofossil analysis with radiocarbon dating has been widely used in detecting past permafrost dynamics in peatlands, however, due to a lack of permafrost‐specific plant indicator species, determining the exact timing of permafrost aggradation remains a challenge. In this study, we investigated if oribatid mites can be used to determine Holocene permafrost aggradation and degradation in Canadian mires. Based on analyses of subfossil oribatid mite assemblages of Holocene peat profiles from two mires in the Hudson Bay Lowlands area, our results suggest that two species, Carabodes labyrinthicus and Neoribates aurantiacus, are useful bioindicators, which can be used in palaeoecological studies determining permafrost histories. Moreover, our results show that subfossil oribatid mite remains can reveal periods of permafrost, which cannot be determined with certainty based on plant macrofossils alone.

A benchmark assessment of ecosystem health indicator species groups at Bali Barat National Park

Bali Barat National Park was assessed for its suitability to receive RFS Protected Area CreditsTM. Part of the requirement is to select indicator groups from among 5 terrestrial taxa, within the eligible forest in the park boundaries, (1) insects - butterflies, (2) amphibian, (3) reptiles, (4) birds, and (5) mammals that can serve as r indicators for the overall ecosystem health of the TNBB. To select indicator groups, a biodiversity survey was conducted for during August-September 2015 in 3 study sites within Bali Barat National Park, Lebak Buah, Megatransect, and Brumbun. Different taxa were surveyed using peer-reviewed methods. The best indicator species within each taxa group (plants, butterflies, herpetofauna, birds and mammals) were defined based on their abundance and distribution in the eligible forest of the project area using Indicator Value method. Potential animal and plant indicator species were then assessed empirically for their cost-effectiveness based on survey effort and cost during the initial survey. Then they were evaluated for generality, functional importance, available scientific knowledge, and cross-taxon representation. Our results suggested that birds would be the best indicator species group, followed by butterflies, and plants. Such indicator is important surrogate for ecosystem health which can be used for conservation management priorities within protected area.

Ecological indicators of near-surface permafrost habitat at the southern margin of the boreal forest in China

Abstract The most dramatic permafrost degradation is expected to occur at the southern edge of permafrost distribution, which is difficult to detect directly on a large scale. Ecological indicators can be used to provide an early signal of changes in terrestrial ecosystems for regional near-surface permafrost habitats and potentially to monitor near-surface permafrost degradation. In this study, plant composition and community structure indicate the near-surface permafrost distribution at the southern edge of the boreal forest and permafrost in northeastern China. The plant species composition and structure of aboveground vegetation were linked to the belowground near-surface permafrost distribution in order to find indicators of changes in vegetation features from permafrost melting. These indicators are essential for assessing changes in permafrost vegetation systems under climate change. Carex schmidtii and C. appendiculata in the herb layer and Betula fruticosa in the shrub layer were found to be specific near-surface permafrost plant indicator species, especially for the wetland permafrost. Shrub cover, moss mat thickness and tree canopy cover are also strongly correlated with near-surface permafrost distribution. The active layer thickness (ALT) showed negative correlations with moss thickness and shrub cover because these features may act as buffers for regional climate warming. We chose the cover of each indicator species, near-surface permafrost-specific community features and geographical information as independent variables to predict the possible distribution of near-surface permafrost in our study region using logistic regression. The results showed that the prediction model had good performance and accuracy. Our study sheds light on early caution of deepening of regional-scale permafrost active layer with vegetation indicators that can further be identified from satellite images.

Ecological infrastructures across Mediterranean agroecosystems: Towards an effective tool for evaluating their ecological quality

The development of reliable evaluation schemes is essential to assess the status of biodiversity, particularly under the current scenario of biodiversity loss across agroecosystems. In these areas, ecological infrastructures contribute heavily to enhance biodiversity and underlying services, and their contribution depends on their ecological quality. Based on the questionnaire by Boller et al. (2004) for temperate areas, we propose a reliable tool for evaluating the ecological quality of woodland patches, hedges and grass strips associated with Mediterranean agroecosystems (simplified questionnaire). Since management practices and organism composition vary across geographical regions, the implementation of evaluation tools adapted to other geographical regions is deemed necessary. The development of the simplified questionnaire followed a five-steps' approach: (i) application of the Boller's questionnaire in the field; (ii) Boller's questionnaire adaptation; (iii) development of the simplified questionnaire through the assessment and simplification of Boller's questionnaire; (iv) evaluation of the simplified questionnaire effectiveness; (v) proposal of plant indicator species associated to the different quality levels obtained from applying the simplified questionnaire as an additional tool for quality assessment that complements such questionnaire. A total of 482 ecological infrastructures were evaluated in La Rioja (Spain) using the Boller's questionnaire, and their vegetation assessed by inventorying their floristic composition. We analyzed the relationship between plant species richness, as a proxy of the overall biodiversity, and the different items included in the Boller's questionnaire. According to these results, a new questionnaire was proposed, in which only variables significantly related to plant species richness were included. Our results showed that the quality groups established when applying our simplified questionnaire were more consistent than those obtained when using the Boller's questionnaire. Overall, 35 plant species resulted as significant indicators for the four levels of quality obtained from applying the simplified questionnaire. We point out that the assessment tool based on simplified questionnaire is straightforward and easy to apply by both experts and non-experts. We also propose the simplified questionnaire development procedure as a guide to create evaluation questionnaires adapted to other ecological infrastructure types.

Hydrology-driven environmental variability determines abiotic characteristics and Oribatida diversity patterns in a Sphagnum peatland system.

We investigated oribatid mite communities in a Sphagnum-dominated boreal peatland system characterised by a mosaic of oligotrophic and meso-eutrophic areas. We aimed to determine the relative importance of environmental factors (pH, Sphagnum nutrient content, water table level, diversity of vascular plants and bryophytes in the surrounding plant community) and spatial variation in influencing abundance, diversity and community composition of aquatic and terrestrial oribatid mites. Among environmental variables, water table level (micro-topography), pH, and K in Sphagnum tissues were the main predictors of Oribatida community structure. Aquatic species were associated with pools; two terrestrial species-Hoplophthiracarus illinoisensis and Nothrus pratensis-were associated with oligotrophic hummocks; the rest of terrestrial species were associated with dryer mesotrophic and eutrophic habitats. Low water table depth (hummocks), high local plant diversity, and high P in Sphagnum tissues were predictors of high abundance of terrestrial Oribatida. Species richness of terrestrial Oribatida was linked with low water table and high plant diversity. For aquatic Oribatida abundance, water table depth was the single most important predictor variable. Plot trophic class (its status on the peatland poor-rich gradient assigned based on plant indicator species) was also a significant predictor of terrestrial Oribatida abundance, richness, and community structure. Spatial structuring was important for terrestrial Oribatida community composition, weak (P < 0.10) for terrestrial Oribatida abundance and richness, and not significant for aquatic Oribatida.

Initial understory vegetation responses following different forest management intensities in Illyrian beech forests

AbstractBackground and questionsHow forest vegetation responds to disturbance continues to be a focal point, especially in the context of biodiversity conservation. To investigate the short‐term effects of forest management on understory vegetation, we asked: (a) Are there any plant indicator species associated with different felling intensities? (b) What are the differences in abundance of plant functional types along the disturbance gradient? (c) How do typical forest species respond to silvicultural treatments?LocationDinaric Mountains, Slovenia.MethodsAt each of three study sites in Illyrian beech forests, nine plots (4,000 m2) were established, comprising a total of 27 plots. Three different felling intensities were implemented at each site, with one third of the plots assigned to each treatment: control, 50% of the growing stock removed and 100% of the growing stock removed. In the centre of each plot, a vegetation survey of vascular plants was done before (in 2012) and two years after (in 2014) felling in a circular sampling area of 400 m2. We employed indicator species analysis, and species were grouped into functional types with respect to their traits.ResultsUnderstory species composition differed significantly between treatments. Forty‐seven species (out of 251) were significantly associated with the 100% felling intensity. This relatively high number of indicators was due to the post‐disturbance colonization of early‐successional, non‐forest species, coupled with the expansion of pre‐treatment resident species. Only one species was a strong indicator for the 50% felled plots, while three species showed a preference for the unfelled plots. Graminoids, tall perennial forbs, annual/biennial forbs and legumes exhibited the most prominent increase in cover at the 50% and 100% felling intensity. Ferns showed non‐significant changes, whereas woody plants exhibited a decrease in the most intensive treatment. In general, most of the typical forest species responded with increased frequency and/or abundance after felling.ConclusionsThe post‐treatment taxonomic and functional composition of plant communities exhibited the largest changes in the most intensively felled stands. Overall, in the short term, ecological conditions in canopy gaps were not modified to an extent that would be detrimental to the persistence of typical forest species.

Warm summers during the Younger Dryas cold reversal

The Younger Dryas (YD) cold reversal interrupts the warming climate of the deglaciation with global climatic impacts. The sudden cooling is typically linked to an abrupt slowdown of the Atlantic Meridional Overturning Circulation (AMOC) in response to meltwater discharges from ice sheets. However, inconsistencies regarding the YD-response of European summer temperatures have cast doubt whether the concept provides a sufficient explanation. Here we present results from a high-resolution global climate simulation together with a new July temperature compilation based on plant indicator species and show that European summers remain warm during the YD. Our climate simulation provides robust physical evidence that atmospheric blocking of cold westerly winds over Fennoscandia is a key mechanism counteracting the cooling impact of an AMOC-slowdown during summer. Despite the persistence of short warm summers, the YD is dominated by a shift to a continental climate with extreme winter to spring cooling and short growing seasons.

Indicator value of oribatid mites in determining past permafrost dynamics in northern European sub‐Arctic peatlands

Permafrost dynamics play an important role in the surface hydrology and carbon balance of northern peatlands. Plant macrofossil analysis with radiocarbon dating has been widely used in detecting past permafrost dynamics in peatlands; however, there is a lack of permafrost‐specific plant indicator species, which makes it challenging to determine the exact timing of historical permafrost aggradation. We investigated the indicator value of oribatid mites in determining past permafrost dynamics in sub‐Arctic peatlands. Analyses of subfossil oribatid mite assemblages of Holocene peat profiles from two mires, one in northern Finland and one in northeastern European Russia, were carried out and interpreted using modern calibration data from the same study areas. The results were compared with previously published reconstructions of permafrost history based on plant macrofossil analyses from the same locations. The results suggest that the oribatid mites Carabodes labyrinthicus, Chamobates borealis and Neoribates aurantiacus are promising indicator species to detect past permafrost occurrence in peatlands. In addition, N. aurantiacus is clearly associated with the presence of lichens, which is particularly useful because lichen remains are rarely preserved in peat deposits. Results are in accordance with earlier studies showing that oribatid mites are useful indicators of past environmental change.