Grazing management of calcareous grasslands and its implications for the conservation of beetle communities

Calcareous grasslands are an important habitat for floral and faunal communities in the UK and Europe. Declines due to changes in management, scrub invasion and agricultural improvement have left much of the remnants of this habitat in a degraded and fragmented state. Grazing, by cattle or sheep, is one of the main management practices used to maintain and improve the floral and faunal quality of calcareous grassland. The long-term impacts of different grazing regimes, however, are poorly understood, particularly in terms of the invertebrate communities. This study contrasted the impacts of recently introduced and long-term sheep or cattle grazing on beetle communities present on one of the largest areas of calcareous grassland in Europe, the Salisbury Plain military training Area, UK. No effects of grazing management on beetle abundance, species. richness or evenness were found, but plant diversity and overall percentage cover of grasses did influence beetle diversity. Proportions of the total number of individuals and overall species richness within beetle guilds (predatory, phytophagous, flower/seed feeders, root feeders and foliage feeders) were strongly influenced by both the duration and type of grazing animal. At the species level, beetle community structure showed significant differences between ungrazed, long-term cattle and long-term sheep grazing treatments. Changes in plant community structure were found to influence beetle community structure. The significance of these results is discussed in terms of the long-term impacts of grazing on beetle community structure, and the benefits of different grazing regimes for the conservation management of calcareous grasslands. (c) 2005 Elsevier Ltd. All rights reserved.

Influence of management type on Diptera communities of coniferous plantations and deciduous woodlands

The contribution of four types of secondary woodlands to Scottish invertebrate biodiversity was investigated for coniferous plantation forestry, riparian ash-alder woodlands, early successional deciduous woodlands and climax deciduous woodlands. Considerable variation in the type and intensity of management within these four woodland types existed. Adult Diptera from 21 families, representing diverse trophic and ecological guilds, were sampled from 31 woodlands in the Aberdeenshire region of northeast Scotland, between June and August 2001. Environmental differences between woodlands were recorded at each site using environmental parameters such as pH and organic matter content, vegetation characteristics, including percentage canopy cover and dominant field layer plant species. Multivariate ordination techniques detected significant responses in the Dipteran communities to soil type, organic matter content, soil pH, field layer plant species richness, dominant field layer plant species and percentage cover of Pteridium aquilinum. Responses in terms of Dipteran abundance, species richness, diversity and evenness were observed to soil type and dominant species of the field layer vegetation. The role of woodland type and management in diversifying Diptera communities is discussed with a view to maintain and possibly enhance Dipteran and other invertebrate communities in Scottish secondary woodlands. (C) 2002 Elsevier Science B.V. All rights reserved.

Characterization of a highly biodiverse floodplain meadow using hyperspectral remote sensing within a plant functional trait framework

We assessed the potential for using optical functional types as effective markers to monitor changes in vegetation in floodplain meadows associated with changes in their local environment. Floodplain meadows are challenging ecosystems for monitoring and conservation because of their highly biodiverse nature. Our aim was to understand and explain spectral differences among key members of floodplain meadows and also characterize differences with respect to functional traits. The study was conducted on a typical floodplain meadow in UK (MG4-type, mesotrophic grassland type 4, according to British National Vegetation Classification). We compared two approaches to characterize floodplain communities using field spectroscopy. The first approach was sub-community based, in which we collected spectral signatures for species groupings indicating two distinct eco-hydrological conditions (dry and wet soil indicator species). The other approach was “species-specific”, in which we focused on the spectral reflectance of three key species found on the meadow. One herb species is a typical member of the MG4 floodplain meadow community, while the other two species, sedge and rush, represent wetland vegetation. We also monitored vegetation biophysical and functional properties as well as soil nutrients and ground water levels. We found that the vegetation classes representing meadow sub-communities could not be spectrally distinguished from each other, whereas the individual herb species was found to have a distinctly different spectral signature from the sedge and rush species. The spectral differences between these three species could be explained by their observed differences in plant biophysical parameters, as corroborated through radiative transfer model simulations. These parameters, such as leaf area index, leaf dry matter content, leaf water content, and specific leaf area, along with other functional parameters, such as maximum carboxylation capacity and leaf nitrogen content, also helped explain the species’ differences in functional dynamics. Groundwater level and soil nitrogen availability, which are important factors governing plant nutrient status, were also found to be significantly different for the herb/wetland species’ locations. The study concludes that spectrally distinguishable species, typical for a highly biodiverse site such as a floodplain meadow, could potentially be used as target species to monitor vegetation dynamics under changing environmental conditions.

Arbuscular mycorrhizal modulation of diazotrophic and denitrifying microbial communities in the (mycor)rhizosphere of Plantago lanceolata

Impacts of divergent arbuscular mycorrhizal (AM) fungi, Glomus intraradices and Gigaspora margarita, on denitrifying and diazotrophic bacterial communities of Plantago lanceolata in nutrient-limited dune soil were assessed. We hypothesized AM species-related modifications that were confirmed in respective bacterial nirK and nifH sequence polymorphism -based community clustering and community variance allocation. The denitrifying community appeared more responsive to AM fungi than the nitrogen-fixing community. Nevertheless, the main explanatory variable, in both cases, was plant age. We conclude that AM fungi can modify N-cycling microbial rhizosphere communities and future work should aim to verify the functional significance and mechanistic basis.

Boosting the globalization of plant proteomics through INPPO: current developments 3 and future prospects

The International Plant Proteomics Organization (INPPO) is a non-profit-organization consisting of people who are involved or interested in plant proteomics. INPPO is constantly growing in volume and activity, which is mostly due to the realization among plant proteomics researchers worldwide for the need of such a global platform. Their active participation resulted in the rapid growth within the first year of INPPO’s official launch in 2011 via its website (www.inppo.com) and publication of the ‘viewpoint paper’ in a special issue of PROTEOMICS (May 2011). Here, we will be highlighting the progress achieved in the year 2011 and the future targets for the year 2012 and onwards. INPPO has achieved a successful administrative structure, the Core Committee (CC; composed of President, Vice-President, and General Secretaries), Executive Council (EC), and General Body (GB) toward achieving the INPPO objectives by its proposed initiatives. Various committees and subcommittees are in the process of being functionalized via discussion amongst scientists around the globe. INPPO’s primary aim to popularize the plant proteomics research in biological sciences has also been recognized by PROTEOMICS where a new section has been introduced to plant proteomics starting January 2012, following the very first issue of this journal devoted to plant proteomics in May 2011. To disseminate organizational activities to the scientific community, INPPO has launched a biannual (in January & July) newsletter entitled “INPPO Express: News & Views” with the first issue published in January 2012. INPPO is also planning to have several activities in 2012, including programs within the Education Outreach committee in different countries, and the development of research ideas and proposals with priority on crop and horticultural plants, while keeping tight interactions with proteomics programs on model plants such as Arabidopsis thaliana, rice, or Medicago truncatula. Altogether, the INPPO progress and upcoming activities are because of immense support, dedication, and hard work of all members of the INPPO family, and also due to the wide encouragement and support from the communities (scientific and non-scientific).

Impacts of plant-based foods in ancestral hominin diets on the metabolism and function of gut microbiota in vitro

Ancestral human populations had diets containing more indigestible plant material than present-day diets in industrialized countries. One hypothesis for the rise in prevalence of obesity is that physiological mechanisms for controlling appetite evolved to match a diet with plant fiber content higher than that of present-day diets. We investigated how diet affects gut microbiota and colon cells by comparing human microbial communities with those from a primate that has an extreme plant-based diet, namely, the gelada baboon, which is a grazer. The effects of potato (high starch) versus grass (high lignin and cellulose) diets on human-derived versus gelada-derived fecal communities were compared in vitro. We especially focused on the production of short-chain fatty acids, which are hypothesized to be key metabolites influencing appetite regulation pathways. The results confirmed that diet has a major effect on bacterial numbers, short-chain fatty acid production, and the release of hormones involved in appetite suppression. The potato diet yielded greater production of short-chain fatty acids and hormone release than the grass diet, even in the gelada cultures, which we had expected should be better adapted to the grass diet. The strong effects of diet on hormone release could not be explained, however, solely by short-chain fatty acid concentrations. Nuclear magnetic resonance spectroscopy found changes in additional metabolites, including betaine and isoleucine, that might play key roles in inhibiting and stimulating appetite suppression pathways. Our study results indicate that a broader array of metabolites might be involved in triggering gut hormone release in humans than previously thought. IMPORTANCE: One theory for rising levels of obesity in western populations is that the body's mechanisms for controlling appetite evolved to match ancestral diets with more low-energy plant foods. We investigated this idea by comparing the effects of diet on appetite suppression pathways via the use of gut bacterial communities from humans and gelada baboons, which are modern-day primates with an extreme diet of low-energy plant food, namely, grass. We found that diet does play a major role in affecting gut bacteria and the production of a hormone that suppresses appetite but not in the direction predicted by the ancestral diet hypothesis. Also, bacterial products were correlated with hormone release that were different from those normally thought to play this role. By comparing microbiota and diets outside the natural range for modern humans, we found a relationship between diet and appetite pathways that was more complex than previously hypothesized on the basis of more-controlled studies of the effects of single compounds.

Endophytic bacterial community composition in wheat (Triticum aestivum) is determined by plant tissue type, developmental stage and soil nutrient availability

Aims: To understand effects of tissue type, growth stage and soil fertilisers on bacterial endophyte communities of winter wheat (Triticum aestivum cv. Hereward). Methods: Endophytes were isolated from wheat grown under six fertiliser conditions in the long term Broadbalk Experiment at Rothamsted Research, UK. Samples were taken in May and July from root and leaf tissues. Results: Root and leaf communities differed in abundance and composition of endophytes. Endophytes were most abundant in roots and the Proteobacteria were most prevalent. In contrast, Firmicutes and Actinobacteria, the Gram positive phyla, were most prevalent in the leaves. Both fertiliser treatment and sample time influenced abundance and relative proportions of each phylum and genus in the endosphere. A higher density of endophytes was found in the Nil input treatment plants. Conclusions: Robust isolation techniques and stringent controls are critical for accurate recovery of endophytes. The plant tissue type, plant growth stage, and soil fertiliser treatment all contribute to the composition of the endophytic bacterial community in wheat. These results should help facilitate targeted development of endophytes for beneficial applications in agriculture.

Engineering a plant community to deliver multiple ecosystem services

The sustainable delivery of multiple ecosystem services requires the management of functionally diverse biological communities. In an agricultural context, an emphasis on food production has often led to a loss of biodiversity to the detriment of other ecosystem services such as the maintenance of soil health and pest regulation. In scenarios where multiple species can be grown together, it may be possible to better balance environmental and agronomic services through the targeted selection of companion species. We used the case study of legume-based cover crops to engineer a plant community that delivered the optimal balance of six ecosystem services: early productivity, regrowth following mowing, weed suppression, support of invertebrates, soil fertility building (measured as yield of following crop), and conservation of nutrients in the soil. An experimental species pool of 12 cultivated legume species was screened for a range of functional traits and ecosystem services at five sites across a geographical gradient in the United Kingdom. All possible species combinations were then analyzed, using a process-based model of plant competition, to identify the community that delivered the best balance of services at each site. In our system, low to intermediate levels of species richness (one to four species) that exploited functional contrasts in growth habit and phenology were identified as being optimal. The optimal solution was determined largely by the number of species and functional diversity represented by the starting species pool, emphasizing the importance of the initial selection of species for the screening experiments. The approach of using relationships between functional traits and ecosystem services to design multifunctional biological communities has the potential to inform the design of agricultural systems that better balance agronomic and environmental services and meet the current objective of European agricultural policy to maintain viable food production in the context of the sustainable management of natural resources.

Spatial structuring of arbuscular mycorrhizal communities in benchmark and modified temperate eucalypt woodlands

Arbuscular mycorrhizal fungi (AMF) are crucial to the functioning of the plant–soil system, but little is known about the spatial structuring of AMF communities across landscapes modified by agriculture. AMF community composition was characterized across four sites in the highly cleared south-western Australian wheatbelt that were originally dominated by forb-rich eucalypt woodlands. Environmentally induced spatial structuring in AMF composition was examined at four scales: the regional scale associated with location, the site scale associated with past management (benchmark woodlands with no agricultural management history, livestock grazing, recent revegetation), the patch scale associated with trees and canopy gaps, and the fine scale associated with the herbaceous plant species beneath which soils were sourced. Field-collected soils were cultured in trap pots; then, AMF composition was determined by identifying spores and through ITS1 sequencing. Structuring was strongest at site scales, where composition was strongly related to prior management and associated changes in soil phosphorus. The two fields were dominated by the genera Funneliformis and Paraglomus, with little convergence back to woodland composition after revegetation. The two benchmark woodlands were characterized by Ambispora gerdemannii and taxa from Gigasporaceae. Their AMF communities were strongly structured at patch scales associated with trees and gaps, in turn most strongly related to soil N. By contrast, there were few patterns at fine scales related to different herbaceous plant species, or at regional scales associated with the 175 km distance between benchmark woodlands. Important areas for future investigation are to identify the circumstances in which recolonization by woodland AMF may be limited by fungal propagule availability, reduced plant diversity and/or altered chemistry in agricultural soils.

Phytophagous insect fauna tracks host plant responses to exotic grass invasion

The high dependence of herbivorous insects on their host plants implies that plant invaders can affect these insects directly, by not providing a suitable habitat, or indirectly, by altering host plant availability. In this study, we sampled Asteraceae flower heads in cerrado remnants with varying levels of exotic grass invasion to evaluate whether invasive grasses have a direct effect on herbivore richness independent of the current disturbance level and host plant richness. By classifying herbivores according to the degree of host plant specialization, we also investigated whether invasive grasses reduce the uniqueness of the herbivorous assemblages. Herbivorous insect richness showed a unimodal relationship with invasive grass cover that was significantly explained only by way of the variation in host plant richness. The same result was found for polyphagous and oligophagous insects, but monophages showed a significant negative response to the intensity of the grass invasion that was independent of host plant richness. Our findings lend support to the hypothesis that the aggregate effect of invasive plants on herbivores tends to mirror the effects of invasive plants on host plants. In addition, exotic plants affect specialist insects differently from generalist insects; thus exotic plants affect not only the size but also the structural profile of herbivorous insect assemblages.

Behavioral suites mediate group-level foraging dynamics in communities of tropical stingless bees

Competition for floral resources is a key force shaping pollinator communities, particularly among social bees. The ability of social bees to recruit nestmates for group foraging is hypothesized to be a major factor in their ability to dominate rich resources such as mass-flowering trees. We tested the role of group foraging in attaining dominance by stingless bees, eusocial tropical pollinators that exhibit high diversity in foraging strategies. We provide the first experimental evidence that meliponine group foraging strategies, large colony sizes and aggressive behavior form a suite of traits that enable colonies to improve dominance of rich resources. Using a diverse assemblage of Brazilian stingless bee species and an array of artificial ""flowers"" that provided a sucrose reward, we compared species` dominance and visitation under unrestricted foraging conditions and with experimental removal of group-foraging species. Dominance does not vary with individual body size, but rather with foraging group size. Species that recruit larger numbers of nestmates (Scaptotrigona aff. depilis, Trigona hyalinata, Trigona spinipes) dominated both numerically (high local abundance) and behaviorally (controlling feeders). Removal of group-foraging species increased feeding opportunities for solitary foragers (Frieseomelitta varia, Melipona quadrifasciata and Nannotrigona testaceicornis). Trigona hyalinata always dominated under unrestricted conditions. When this species was removed, T. spinipes or S. aff. depilis controlled feeders and limited visitation by solitary-foraging species. Because bee foraging patterns determine plant pollination success, understanding the forces that shape these patterns is crucial to ensuring pollination of both crops and natural areas in the face of current pollinator declines.

Phytophthora cinnamomi in native vegetation communities of southern Victoia - morphological variation and paragyny among isolates

Morphology has often been used as an indicator of variability within species. The present study investigated morphological and physiological characteristics of isolates of Phytophthora cinnamomi collected from diseased vegetation communities at Anglesea, Victoria, and isolates collected from other regions in the State. Characteristics studied included growth rate on potato-dextrose agar (PDA), corn-meal agar and V8-juice agar at 24°C, growth rate on V8 agar at 15°C, colony morphology on PDA, sporangial and gametangial morphology, sporangial production and mating type. Phenotypic variation was demonstrated in radial growth rate, colony morphology and sporangial dimensions. Sporangial and oogonial dimensions and sporangial production were not significantly different between isolates from different geographical regions. All isolates were found to be of the A2 mating type suggesting variation was derived asexually. Paragynal associations, in an organism characteristically defined as amphigynal, were observed following crossing with A1 isolates. This is the first such study undertaken in southern Victoria. The findings highlight the importance of appropriate management of an area of such high conservation value as the Anglesea Heath to contain the current infection and to prevent introduction of new isolates into the area.

Spatial model for predicting the presence of cinnamon fungus (Phytophthora cinnamomi) in sclerophyll vegetation communities in south-eastern Australia

The pathogen Phytophthora cinnamomi causes extensive 'dieback' of Australian native vegetation. This study investigated the distribution of infection in an area of significant sclerophyll vegetation in Australia. It aimed to determine the relationship of infection to site variables and to develop a predictive model of infection. Site variables recorded at 50 study sites included aspect, slope, altitude, proximity to road and road characteristics, soil profile characteristics and vegetation attributes. Soil and plant tissues were assayed for the presence of the pathogen. A geographical information systyem (GIS) was employed to provide accurate estimations of spatial variables and develop a predictive model for the distribution of P. cinnamomi. The pathogen was isolated from 76% of the study sites. Of the 17 site variables initially investigated during the study a logistic regression model identified only two, elevation and sun-index, as significant in determining the probability of infection. The presence of P. cinnamomi infection was negatively associated with elevation and positively associated with sun-index. The model predicted that up to 74% of the study area (11 875 ha) had a high probability of being affected by P. cinnamomi. However, the present areas of infection were small, providing an opportunity for management to minimize spread into highly susceptible uninvaded areas.

Plant pathogens causing vegetation dieback: a serious threat to the conservation of small mammals in Australia

The soil-borne plant pathogen Phytophthora cinnamomi occurs in most Australian states. It is pathogenic to many Australian species, particularly the Proteaceae, Fabaceae, Dillineaceae and Epacridaceae. In Western Australia, c. 2000 of the 9000 endemic plant species are directly affected by the disease. The epidemic of plant deaths caused by P. cinnamomi is recognised as one of 11 Key Threatening Processes to the Australian Environment, and is now also acknowledged as a potential threat fauna in a range of communities. The implications of landscape modification due to the effects of P. cinnamomi dieback prompted our research, designed to measure the distribution and abundance of small mammals in disease-affected ecosystems. This study was in the Jarrah (Eucalyptus marginata) forests in the Darling Range, Western Australia and measured the distribution and abundance of one small mammal species, the Mardo (Antechinus flavipes) by Elliott trapping in forests with (1) high, (2) mixed and (3) no evidence of Phytophthora dieback. Trap success was highest in sites with no effect of Phytophthora (7.3 animals per 100 trap nights), whereas the lowest trap success was recorded at the high impact sites (0.67 animals per 100 trap night). There was a significant difference in trap success of Mardos in Elliott trapping over 1800 trap nights (x²= 23.19, d.f = 5, p < 0.001). An examination of the distribution of individuals and sexes suggests that Phytophthora-affected sites act as sinks for Mardos, while source areas are healthy, unaffected Jarrah forest.

Succession of small mammal communities after fire and reintroduction of the swamp antechinus 'Antechinus minimus'

This thesis is involved with changes that have occurred to small mammal populations following a major disturbance in the Anglesea region as a result of the 1983 Ash Wednesday fires. Fire, with its effects on spatial and temporal heterogeneity, was found to be an important factor in the maintenance of vegetation and small mammal community structure and diversity in the region. Successional changes in vegetation and small mammal communities were described by multivariate analyses, using data collected annually from 22 study sites. The use of factor analysis techniques, in reducing the annual capture data content, enabled long-term changes in the structure of mammal communities to be interpreted. The small mammal communities in the coastal heath and forest vegetation in the Anglesea region show evidence of a general resilience, (the degree and speed of recovery), to disturbance. Two phases of successional response to fire by mammal species have been proposed; a ‘re-establishment’ phase which occurs in the initial 5-6 years post-fire and is accompanied by rapid increase in species’ abundance, and a subsequent ‘maintenance’ phase accompanied by relatively minor changes in abundance. Habitat Suitability Indices were produced relating to these phases. Vertical density measures of understorey shrubs and herb layers showed significant relationships with small mammal species abundance at the study sites. Long term studies following major disturbances are needed to distinguish between short term recovery of plant and animal species and long term changes in these species. Studies extending over a number of years enable a better directional view of changes in small mammal communities than can be determined from . observations made over a short period. As a part of the investigation into temporal change, it was proposed to undertake trial reintroductions of the Swamp antechinus, Ant echinus minimus, a marsupial dasyurid species which was trapped in the area prior to the 1983 fire, but rarely subsequently. Other more commonly observed native small mammal species (e.g. Rattus fuscipes,R. lutreolus, Antechinus stuartii, Sminthopsis leucopus) had re-invaded the proposed reintroduction site after this fire. Failure of A. minimus to re-establish may have been due to spatial separation of the pre-fire populations coupled with the extensive area burnt in 1983, A source population of the species was located about 100km to the west and habitat utilization and interspecific and niche relationships between the species making the small mammal community explored. Discriminant analysis revealed some spatial separation of species within a habitat based on structural vegetation factors rather than floristic factors. Temporal separation of species was observed, asA. minimus were more active than Rattus species during daylight periods. There was evidence of micro-habitat selection by species, and structural vegetation factors were most commonly identified in statistical analyses as contributing towards selection by small mammal species. Following a theoretical modelling study three reintroduction trials were carried out near Anglesea during 1992-94. Individuals were subsequently radio tracked, and habitat relationships between the species in the small mammal community investigated. Although successful breeding of A, minimus occurred during the latter two trials, the subsequent fate of offspring was not determined. Invasive techniques required to adequately monitor young animals were considered potentially too damaging. Telemetry studies indicated a preference of A. minimus for short, wet heath vegetation. Structural vegetation factors were identified as being significant in discriminating between capture locations of species. Small scale and inexpensive trial reintroductions have yielded valuable additional data on this species and may be viewed as a useful tool in the conservation of other small native mammals.