Relative Proportions Of Species Research Articles

How gradients of climate and soil determine Mediterranean annual‐rich dryland vegetation

AbstractQuestionsDryland annual plant communities constitute the most species‐rich small‐scale vegetation in the Mediterranean. Nevertheless, the composition and diversity of these units and the factors controlling their variation are still insufficiently understood. Therefore, we investigated species composition and richness patterns in relation to important environmental gradients provided by climate and soil.LocationCentral Crete, Greece.MethodsThe study is based on 82 plots of 4 m2 sampled at altitudes between 11 and 1400 m a.s.l. We conducted vegetation relevés and soil analyses. We used generalised additive models to model species richness and community characteristics along the studied gradients. We then performed distance‐based redundancy analysis to determine the main environmental factors influencing species composition. To determine species of diagnostic value for bedrock types, we applied an indicator species analysis. Correlation tests were used to test the performance of the South Aegean Plant Indicator Values on our dataset.ResultsWe recorded 347 taxa (species and subspecies) of 43 plant families, and mean species numbers of 47.2 ± 12.5 per plot. While overall species richness varied only slightly along the analysed environmental gradients, significant changes were observed for relative proportions of species from different life forms and families. Soil pH and elevation had the highest influence on the variation in species composition (21.0% explained). We found 22 species indicative of calcareous rock and 24 species indicative of lime‐deficient rock types. The South Aegean Plant Indicator Values were relatively strongly correlated with environmental variables.ConclusionsResults indicate considerable species turnover both along climatic (elevation) and soil gradients, highlighting the special importance of soil pH. The data provided by our study are expected to supply relevant ecological background information for a pending classification of East Mediterranean annual‐rich vegetation.

Species Diversity Regulates Ecological Strategy Spectra of Forest Vegetation Across Different Climatic Zones.

Ecological strategy is the tactics employed by species in adapting to abiotic and biotic conditions. The ecological strategy spectrum is defined as the relative proportion of species in different ecological strategy types within a community. Determinants of ecological strategy spectrum of plant community explored by most previous studies are about abiotic factors. Yet, the roles of biotic factors in driving variations of ecological strategy spectra of forest communities across different geographic regions remains unknown. In this study, we established 200 0.04-ha forest dynamics plots (FDPs) and measured three-leaf functional traits of tree and shrub species in four forest vegetation types across four climatic zones. Based on Grime’s competitor, stress-tolerator, ruderal (CSR) triangular framework, and the StrateFy method, we categorized species into four ecological strategy groups (i.e., C-, S-, Int-, and R-groups) and related the ecological spectra of the forests to three species diversity indices [i.e., species richness, Shannon-Wiener index, and stem density (stem abundance)]. Linear regression, redundancy analysis, and variance partition analysis were utilized for assessing the roles of species diversity in regulating ecological strategy spectra of forest communities across different climatic zones. We found that the proportion of species in the C- and Int-groups increased, while the proportion of species in the S-group decreased, with the increase of three indices of species diversity. Among the three species diversity indices, stem abundance played the most important role in driving variations in ecological strategy spectra of forests across different climatic zones. Our finding highlights the necessity of accounting for biotic factors, especially stem abundance, in modeling or predicting the geographical distributions of plant species with varied ecological adaptation strategies to future environmental changes.

Winners and losers in a changing climate: how will protected areas conserve red list species under climate change?

AbstractAimA fundamental challenge to protected area‐based conservation is that protected areas are typically established under assumptions of environmental stationarity. With a rapidly changing climate, this assumption of stationarity is violated, and climate change could push some species beyond the bounds of currently protected areas. Here, we evaluate the efficacy of protected areas in conserving threatened plant biodiversity under future climate projections.LocationSouth Africa.MethodsWe use ensemble species distribution modelling to map the projected distribution of South Africa's ~1200 threatened endemic plant species under present‐day and projected climate scenarios for 2050. We quantify the performance of the existing protected area network by examining changes in the relative proportion of species’ projected geographic extents within protected areas. We then examine whether current IUCN Red List status is a good predictor of climate ‘winners’ and 'losers.'ResultsWe find that 56%–66% of species may have a greater proportion of their projected range extent falling within protected areas in 2050 under climate scenarios of mitigated and upsurge greenhouse gas emissions (Representative Concertation Pathways 4.5 and 8.5). However, this increase in the proportion of range protected is frequently associated with range contraction outside of protected areas. We also show that current threat intensity is not a good indicator of which species will lose versus gain increased protection.Main conclusionsOur results suggest that the existing reserve network is surprisingly robust to projected range shifts; however, we also identify regions where species protection needs to be improved. In addition, we suggest that there is an urgent need to better incorporate future climate threats into the assessment of species extinction risks.

Shifts in ecological strategy spectra of typical forest vegetation types across four climatic zones

Ecological strategy spectrum is the relative proportion of species in different categories of ecological strategies in a biotic community. Here, we explored ecological strategy spectra in typical forest vegetation types across four climatic zones in China. We classified ecological strategy categories by using the “StrateFy” ordination method based on three leaf functional traits. Results showed that the predominant ecological strategies of species in the tropical rainforest were CS-selected, and the predominant categories in the evergreen-deciduous broadleaved mixed forest and warm-temperate coniferous-broadleaved mixed forest were CSR and S/CSR categories respectively, whereas those in the cold-temperate coniferous forest were the S-selected ones. Ecological strategy richness of forest vegetation decreased significantly with the increase of latitude. The categories of ecological strategies with more component S increased while those with more component C decreased with the change of typical forest vegetation types from tropical rainforest through evergreen-deciduous broadleaved mixed forest and warm-temperate coniferous-broadleaved mixed forest to cool-temperate coniferous forest. Our findings highlight the usefulness of Grime’s C-S-R scheme for predicting the responses of vegetation to environmental changes, and the results are helpful in further elucidating species coexistence and community assembly in varied climatic and geographic settings.

Distribution of seed dormancy classes across a fire-prone continent: effects of rainfall seasonality and temperature.

Different seed dormancy classes control the timing of germination via different cues. The ecological dissimilarities between classes therefore suggest that they are likely to be subject to different selective pressures, and that species within each class will have diverse functional responses. We aimed to investigate this by assessing how variation in the distribution of dormancy classes is correlated with regional environmental factors, in particular rainfall seasonality and temperature. Additionally, we compare the relative proportions of species with physiological (PD) or physical (PY) dormancy to assess whether dormancy class influences their ability to persist under different rainfall seasonality regimes. Dormancy class was assigned for 3990 species from 281 genera occurring across two climate regions, with either winter or aseasonal rainfall, across temperate fire-prone Australia. All regions have similar vegetation and fire regimes. Using a Bayesian framework, we compared the distribution of dormancy classes across temperature and rainfall climate gradients, for threatened and common species. A high dormant:non-dormant species ratio highlighted the critical role of dormancy across our study regions. Critically, species showing PD were more likely to be threatened in aseasonal rainfall climate regions. Our results support the assumption that dormancy is favoured in environments with stochastic disturbance.

Efficacy of metabarcoding for identification of fish eggs evaluated with mock communities.

There is urgent need for effective and efficient monitoring of marine fish populations. Monitoring eggs and larval fish may be more informative than that traditional fish surveys since ichthyoplankton surveys reveal the reproductive activities of fish populations, which directly impact their population trajectories. Ichthyoplankton surveys have turned to molecular methods (DNA barcoding & metabarcoding) for identification of eggs and larval fish due to challenges of morphological identification. In this study, we examine the effectiveness of using metabarcoding methods on mock communities of known fish egg DNA. We constructed six mock communities with known ratios of species. In addition, we analyzed two samples from a large field collection of fish eggs and compared metabarcoding results with traditional DNA barcoding results. We examine the ability of our metabarcoding methods to detect species and relative proportion of species identified in each mock community. We found that our metabarcoding methods were able to detect species at very low input proportions; however, levels of successful detection depended on the markers used in amplification, suggesting that the use of multiple markers is desirable. Variability in our quantitative results may result from amplification bias as well as interspecific variation in mitochondrial DNA copy number. Our results demonstrate that there remain significant challenges to using metabarcoding for estimating proportional species composition; however, the results provide important insights into understanding how to interpret metabarcoding data. This study will aid in the continuing development of efficient molecular methods of biological monitoring for fisheries management.

Application of Ground-Based Lidar and Gap Intercept Measurements to Quantify a Shrub Configuration Metric within Greater Sage-Grouse Nesting Habitat

Vegetation composition (i.e., relative proportion of species) and configuration (i.e., horizontal and vertical arrangement of the plant components) in sagebrush-steppe ecosystems are fundamental determinants of the suitability of nesting habitat for Greater Sage-Grouse (Centrocercus urophasianus). The spatial arrangement of shrub and herbaceous canopy cover conceals Greater Sage-Grouse from predators and protects the nest from natural hazards, and gaps in vegetative cover provide escape routes for hens. Most sage-grouse habitat studies quantify vegetation composition, but few quantify habitat configuration at fine scales. We used ground-based lidar (light detection and ranging) data from Greater Sage-Grouse nesting habitat to test the applicability of a metric calculated from the traditional canopy gap intercept measurements to quantify shrub canopy configuration (shrub patchiness). Vegetation surveys were conducted on 30 randomly selected nest and non-nest sites (15 of each); we acquired high-resolution ground-based lidar data for 12 plots at 3 nest locations. Variation in canopy gap size was used as a metric to represent shrub configuration characteristics. We measured the variability in gap size among shrubs within lidar point cloud data sets using a lacunarity index at multiple scales. We measured variability of gaps from line transects by calculating the variance to mean-square ratio of gap size. Correlations (r) between measures of gap size variation from the 2 techniques ranged from 0.76 to 0.83 (r2 = 0.58–0.69). Our results support the use of canopy gap intercept measures to quantify configuration (patchiness) of shrub cover and thus complement vegetative composition metrics. Gap sizes were more variable at nest sites than at non-nest sites, suggesting that gap size variability may be a useful vegetative configuration metric to characterize sage-grouse nesting habitat. The fine-scale habitat metrics we evaluated provide a more refined tool for land managers to characterize local variation in wildlife habitat within shrubland ecosystems and can be derived from the existing gap intercept data.

Correlation between the interfacial ion dynamics and charge storage properties of poly(ortho-phenylenediamine) electrodes exhibiting high cycling stability

An integrated electrogravimetric study based on electrochemical quartz crystal microbalance (EQCM) unravels the interfacial ion transfer phenomena of the poly(ortho-phenylenediamine) (PoPD) thin film electrodes. Through a methodology coupling QCM with electrochemical impedance spectroscopy (ac-electrogravimetry), our work indicates that charge compensation process of PoPD in aqueous electrolytes (in acidified NaCl) occurs with the participation of multiple species, each playing a role at different temporal scales. The PoPD films are tested in a 2 electrode Swagelok cell in which Zn is used as both reference and counter electrodes and exhibit excellent stability over 8000 cycles with a relatively high specific capacitance of about 110 F g−1 at 30 C (0.63 mA cm−2) current density. The high rate capability and the excellent cycling stability of the PoPD electrodes are correlated to the electrolyte composition and the significant role of H+ to the charge compensation process is unravelled, which is made possible with coupled electrogravimetric methods of our study. By determining the interfacial flux dynamics and as well as the relative proportions of species transferred at the electrode/electrolyte interface, our results contribute to the understanding of the charge-discharge process of PoPD polymer, yet underexplored but emerging as a pseudo-capacitive electrode material.

Developing Foram-AMBI for biomonitoring in the Mediterranean: Species assignments to ecological categories

Abstract Most environmental bio-monitoring methods using the species composition of marine faunas define the Ecological Quality Status of soft bottom ecosystems based on the relative proportions of species assigned to a limited number of ecological categories. In this study we analyse the distribution patterns of benthic foraminifera in the Mediterranean as a function of organic carbon gradients on the basis of 15 publications and assign the individual species to five ecological categories. Our categories (of sensitive, indifferent and 3rd, 2nd and 1st order opportunists) are very similar to the ecological categories commonly used for macrofauna, but show some minor differences. In the 15 analysed publications, we considered the numerical data of 493 taxa, of which 199 could be assigned. In all 79 taxa were classified as sensitive, 60 as indifferent, 46 as 3rd order, 12 as 2nd order and 2 as 1st order opportunists. The remaining 294 taxa are all accessory, and will only marginally contribute to biotic indices based on relative species proportions. In this paper we wanted also to explain the methodology we used for these species assignments, paying particular attention to all complications and problems encountered. We think that the species list proposed here will constitute a highly useful tool for foraminiferal bio-monitoring of soft bottoms in the Mediterranean Sea, which can be used in different ecological indices (Foram-AMBI and similar methods). With additional information becoming available in the next few years, it will be possible to expand the list, and, if necessary, to apply some minor corrections. As a next step, we intend to test this species list using several biotic indices, in a number of independent data sets, as soon as these will become available.

To what extent the size fraction affects an interpretation of planktonic foraminiferal assemblages

Study of planktonic foraminifera, sampled from two levels of a 26 cm thick core, recovered at 1,200 m water depth, sheds some lights on the composition of foraminiferal assemblages that occur in the Southern Adriatic. Altogether 15 planktonic species (including one referred as undeterminable and two species recorded for the first time in the eastern Adriatic Sea) identified from 0-2 cm and 24-26 cm sediment intervals, were grouped into two assemblages: >63 μm fraction Turborotalita quinqueloba and >125 μm fraction as Globigerina bulloides-Globigerinoides ruber. The differences in core-top and core-bottom assemblages lie in: a) change in the relative proportion of some species; and b) slight differences in diversity indices. The relative proportions of species are strongly controlled by sieve mesh size, whereas the slight increase in diversity follows the increase in sieve mesh size. The benthic foraminifera, although constituting a negligible quantitative factor, show a slight increase in abundance and diversity of species with age.

Cambios en la diversidad funcional del sotobosque y la tasa de descomposición frente a diferentes intensidades de uso silvopastoril en el noroeste de la Patagonia, Argentina

Functional diversity loss by human land-use changes is of great importance for achieving sustainable management, as it plays a key role in ecosystem functioning through a direct influence over ecological processes. In northwest Patagonian forests, livestock production is among the main activities affecting natural ecosystems. The aim of the study was to characterize changes in functional diversity of understory vegetation in sites with different silvopastoral use intensity, and the effects that these variations may have on rate of litter decomposition in mixed forests of cypress and coihue of southwest Rio Negro Province, Argentina. Changes in plant functional traits (life cycle, life style, architecture, habitat, leaf size, leaf texture and root system) were characterized, and the decomposition rate of each site's litter was quantified. Our results showed that both functional diversity index (FD Q ) and decomposition rate were higher under high silvopastoral use intensity, but the relationship was not significant. Results also showed that certain plant functional traits (i.e., rosette architecture, prostrate habitat and fern life form) have a significant effect on litter lost weight. Under high silvopastoral use intensity, the relative proportion of species with rosette architecture and prostrate habitat increases, which led to an increase in decomposition rate. This indicates that silvopastoral activity may modify the original community composition towards species with a rapid resource acquisition, altering also nutrient cycling. In this sense, ecosystem functioning seems to be influenced by certain functional traits, rather than functional diversity itself.

Similar bird communities in homegardens at different distances from Afromontane forests

SummaryHuman modified landscapes make up a growing proportion of the tropics, but are relatively little studied. The spatial distribution of remnant vegetation can structure and shape local biodiversity, affecting the provisioning of ecosystem services and regulation of pest problems. We compared species composition, abundance and functional diversity of birds between forest and homegardens close to (0–100 m) and further away from (1,500–2,000 m) moist evergreen Afromontane forests in south-western Ethiopia. We thoroughly inventoried birds with point counts and mist netting in two forest sites and three garden sites of each type. Gardens differed in general species composition from forests, with fewer forest specialist species (7% versus 29% of recorded species), but instead supported many other species that were rarely encountered in the forests. Overall gardens had higher numbers of species than forests. Homegardens close to the forest and further from the forest were similar to each other in terms of species richness and overall species composition. Both garden types had a similar composition in terms of the relative proportion of species with different habitat preferences as well as the composition of species from different feeding guilds. The lack of forest specialists in even the most structurally complex part of the agricultural landscape close to forest edges suggests that the last larger forest remnants are critical for conservation of forest specialists. Nonetheless, homegardens maintain rich bird diversity that also should be considered in a biodiversity conservation context. Further research is needed to establish to what extent the richness and composition of the agro-ecological bird fauna is regulated by the existence of forest patches in the region. Our results could not resolve this question since gardens two kilometers from the forest edge were similar in composition to gardens close to the forest edges.

Separating the effects of composition and fictive temperature on Al and B coordination in Ca, La, Y aluminosilicate, aluminoborosilicate and aluminoborate glasses

Glass transition temperatures often change significantly (100's of degrees) as the boron oxide to silica ratio, or the field strength of the modifier oxide, is varied in aluminoborosilicate glasses. At the same time, fictive temperature itself can strongly affect the glass structure, most notably in the coordination environments of the network cations boron and aluminum. The latter are especially significant when proportions of [5]Al (AlO5 groups) and [6]Al (AlO6 groups) are high, as in glasses with high field-strength (small, highly charged) modifier cations. To obtain a clearer picture of how composition and temperature independently control structure, we present new data from differential scanning calorimetric (DSC) and high-field 11B and 27Al NMR on a series of Ca, La, and Y aluminosilicate, aluminoborosilicate and aluminoborate glasses prepared with different cooling rates, and compare results in detail with other recently published data on the same compositional joins. We find that previous, apparently disparate results on effects of temperature on Al coordination are in fact related to B/Si ratios: average Al coordination number increased with increased T in aluminosilicates and low-B aluminoborosilicates, but decreased with increased T in glasses with high B/Si ratios, indicating some interaction of the two network cations. We find that effects of T on boron coordination (always lower at higher T) are consistent with a simple thermodynamic view, but may be difficult to detect in some compositions simply because of relative proportions of species. We confirm as well that in boron-rich aluminoborosilicates, B and Al coordination number decreases with increasing temperature are quantitatively linked when calculated per formula unit, again suggesting a strong coupling, and that Al coordination systematically increases with modifier field strength and B2O3/SiO2 ratio.

Species-specific responses to community density in an unproductive perennial plant community.

Most studies of density dependent regulation in plants consider a single target species, but regulation may also occur at the level of the entire community. Knowing whether a community is at carrying capacity is essential for understanding its behaviour because low density plant communities may behave quite differently than their high density counterparts. Also, because the intensity of density dependence may differ considerably between species and physical environments, generalizations about its effects on community structure requires comparisons under a range of conditions. We tested if: (1) density dependent regulation occurs at the level of an entire plant community as well as within individual species; (2) the intensity (effect of increasing community density on mean plant mass) and importance (the effect of increasing density, relative to other factors, on mean plant mass) of competition increases, decreases or remains unchanged with increasing fertilization; (3) there are species-specific responses to changes in community density and productivity. In 63 1 m2 plots, we manipulated the abundance of the nine most common species by transplanting or removing them to create a series of Initial Community Densities above and below the average natural field density, such that the relative proportion of species was consistent for all densities. Plots were randomly assigned to one of three fertilizer levels. At the community level, negative density dependence of mean plant size was observed for each of the 4 years of the study and both the intensity and importance of competition increased each year. At the species level, most species' mean plant mass were negatively density dependent. Fertilizer had a significant effect only in the final year when it had a negative effect on mean plant mass. Our data demonstrate a yield-density response at the entire community-level using perennial plant species in a multi-year experiment.

Wrasse (Labridae) as cleaner fish in salmonid aquaculture – The Hardangerfjord as a case study

Several species of wrasse (Labridae) are used as cleaner fish to remove salmon lice from farmed Atlantic salmon. We estimated the fishery and use of wrasse in Hardangerfjord. The estimated numbers of labrids used on salmon and rainbow trout farms varied between 86,000 and 251,000 from 2002–2006, but increased to as much as 1.1 million in 2009 and 2010. A total of 93,500 kg (around 1.54 million) labrids were reported landed during 2000–2010. Corkwing wrasse (Symphodus melops) was by far the most important wrasse species: 52% by weight and 56% by number. Ballan wrasse (Labrus bergylta) made up 34% by weight but only 14% by number (due to its larger size). The relative proportion of species between the different sampling locations in the fjord was significantly different, as was the condition factor of some species. Goldsinny wrasse (Ctenolabrus rupestris) had the slowest growth of the labrids in this study, and did not reach the minimum commercial catch size (11 cm) before they were 4–5 years old. Very few goldsinny caught were over that size. Corkwing reach commercial size in 1–2 years. The results of this study indicate that wrasse should be protected during the spawning season. Species such as goldsinny grow so slowly that they will most likely be collected several times in heavily fished areas but discarded because they are smaller than the minimum allowable size. This could be avoided through the use of modified traps with escape routes for undersized fish. This study represents a first step towards establishing a knowledge-based management plan for the wrasse fishery.

The Vertical Distribution of Micro- and Small Mesozooplankton in the Central Red Sea

AbstractThe abundance and taxonomic composition of plankton sampled with nets of 0.1 mm mesh size were determined at the Atlantis II Deep, central Red Sea, in October and November 1980, from the surface to a depth of 1650 m. The fine mesh nets yielded three times as much total plankton biomass and thirty times the number of metazoan organisms compared to what was collected during earlier investigations using nets with a larger, 0.3 mm mesh size. The patterns of vertical distribution, determined by using the two different mesh sizes, were similar with respect to the gradients of plankton abundance but different with regard to the relative proportions of species and higher taxa. When the smaller metazoans were included by the use of fine mesh nets, cyclopoid copepodids became more numerous than the calanoid copepodids in all depth layers sampled, and their relative importance increased with depth. Between 200 m and 1050 m depth, over 50% of all copepodids belonged to the cyclopoid genus Oncaea. A review of ...

Incidence, risk factors, and outcomes of Fusobacterium species bacteremia

BackgroundFusobacterium species (spp.) bacteremia is uncommon and has been associated with a variety of clinical presentations. We conducted a retrospective, population based study to determine the relative proportion of species in this genus causing bacteremia and the risk factors for infection and adverse clinical outcomes.MethodsAll cases of Fusobacterium spp. bacteremia detected at a regional microbiology laboratory serving outpatient and acute care for a population of approximately 1.3 million people over 11 years were identified from a computerized database. Clinical data on these cases was extracted from an administrative database and analyzed to determine underlying risk factors for and outcomes of infection.ResultsThere were 72 incident cases of Fusobacterium spp. bacteremia over the study period (0.55 cases/100,000 population per annum). F. nucleatum was the most frequent species (61%), followed by F. necrophorum (25%). F. necrophorum bacteremia occurred in a younger population without underlying comorbidities and was not associated with mortality. F. nucleatum bacteremia was found in an older population and was associated with underlying malignancy or receiving dialysis. Death occurred in approximately 10% of F. nucleatum cases but causality was not established in this study.ConclusionsFusobacterium spp. bacteremia in our community is uncommon and occurs in approximately 5.5 cases per million population per annum. F. necrophorum occurred in an otherwise young healthy population and was not associated with any mortality. F. nucleatum was found primarily in older patients with chronic medical conditions and was associated with a mortality of approximately 10%. Bacteremias from other Fusobacterium spp. were rare.

Shrub encroachment shifts the bioclimatic limit between marcescent and sclerophyllous oaks along an elevation gradient in west‐central Spain

AbstractQuestions(1) Does shrub encroachment affect the regeneration of two contrasting species of oak along an elevation gradient in the west‐central Iberian Peninsula? (2) Do different nurse shrubs have any relevant species‐specific effects along the gradient? (3) Does shrub encroachment affect the location of the bioclimatic limit between these two oak species along the elevation gradient?LocationTwelve sites distributed from the Arribes del Duero plains to the Sistema Central mountains (Salamanca province, Spain).MethodsWe measured the regeneration of two contrasting oak tree species (Quercus ilex subsp. ballota Samp – sclerophyllous, Q. pyrenaica Willd – marcescent) as the relative percentage cover of seedlings and saplings (<1.3‐m high) in plots 10 m in diameter distributed in stands of different age. We fixed the bioclimatic limit at 50% relative proportion of species in each plot, i.e. whether one species was more abundant than the other in a plot. Shrub stand age was estimated by counting growth rings in the principal stems of the oldest shrubs in a plot. We fitted generalized linear mixed models to analyse the effects of elevation, specific nurse shrub and shrub stand age on regeneration and the probability of one species being more abundant than the other.ResultsThe regeneration and relative proportion of Q. ilex (sclerophyllous) decreased with elevation. Regeneration did not vary with shrub encroachment, although the relative proportion increased notably in the youngest stands. In turn, regeneration and relative proportion of Q. pyrenaica (deciduous) significantly increased towards the upper sites and mature shrub stands. We found no evidence of specific nurse shrub effects on regeneration or the probability of one species being more abundant than the other in either of the two species of oak.ConclusionsThe bioclimatic limit between the two contrasting species of oak shifted with shrub stand age along the elevation gradient. Land practices preventing shrub encroachment can thus indirectly shift this limit towards higher elevations. The effects of shrubs may be critical in resolving the climatic and land‐use effects on elevation shifts of species under changing conditions in bioclimatic transitions.

The impact of agricultural intensification and land-use change on the European arable flora

The impact of crop management and agricultural land use on the threat status of plants adapted to arable habitats was analysed using data from Red Lists of vascular plants assessed by national experts from 29 European countries. There was a positive relationship between national wheat yields and the numbers of rare, threatened or recently extinct arable plant species in each country. Variance in the relative proportions of species in different threat categories was significantly explained using a combination of fertilizer and herbicide use, with a greater percentage of the variance partitioned to fertilizers. Specialist species adapted to individual crops, such as flax, are among the most threatened. These species have declined across Europe in response to a reduction in the area grown for the crops on which they rely. The increased use of agro-chemicals, especially in central and northwestern Europe, has selected against a larger group of species adapted to habitats with intermediate fertility. There is an urgent need to implement successful conservation strategies to arrest the decline of this functionally distinct and increasingly threatened component of the European flora.

Dynamic changes in the microbial community composition in microbial fuel cells fed with sucrose

The performance and dynamics of the bacterial communities in the biofilm and suspended culture in the anode chamber of sucrose-fed microbial fuel cells (MFCs) were studied by using denaturing gradient gel electrophoresis (DGGE) of PCR-amplified partial 16S rRNA genes followed by species identification by sequencing. The power density of MFCs was correlated to the relative proportions of species obtained from DGGE analysis in order to detect bacterial species or taxonomic classes with important functional role in electricity production. Although replicate MFCs showed similarity in performance, cluster analysis of DGGE profiles revealed differences in the evolution of bacterial communities between replicate MFCs. No correlation was found between the proportion trends of specific species and the enhancement of power output. However, in all MFCs, putative exoelectrogenic denitrifiers and sulphate-reducers accounted for approximately 24% of the bacterial biofilm community at the end of the study. Pareto-Lorenz evenness distribution curves extracted from the DGGE patterns obtained from time course samples indicated community structures where shifts between functionally similar species occur, as observed within the predominant fermentative bacteria. These results suggest the presence of functional redundancy within the anodic communities, a probable indication that stable MFC performance can be maintained in changing environmental conditions. The capability of bacteria to adapt to electricity generation might be present among a wide range of bacteria.