Biotic Groups Research Articles

Production-ecological modelling explains the difference between potential soil N mineralisation and actual herbage N uptake

We studied two different grassland fertiliser management regimes on sand and peat soils: above-ground application of a combination of organic N-rich slurry manure and solid cattle manure (SCM) vs. slit-injected, mineral N-rich slurry manure, whether or not supplemented with chemical fertiliser (non-SCM). Measurements of field N mineralisation as estimated from herbage N uptake in unfertilised plots were compared with (i) potential N mineralisation as determined from a standard laboratory soil incubation, (ii) the contribution of groups of soil organisms to N mineralisation based on production-ecological model calculations, and (iii) N mineralisation calculated according to the Dutch fertilisation recommendation for grasslands. Density and biomass of soil biota (bacteria, fungi, enchytraeids, microarthropods and earthworms) as well as net plant N-uptake were higher in the SCM input grasslands compared to the non-SCM input grasslands. The currently used method in Dutch fertilisation recommendations underestimated actual soil N supply capacity by, on average, 102kg Nha−1 (202 vs. 304kgha−1=34%). The summed production-ecological model estimate for N mineralisation by bacteria, fungi, protozoa, and enchytraeids was 87–120% of the measured potential soil N mineralisation. Adding the modelled N mineralisation by earthworms to potential soil N mineralisation explained 98–107% of the measured herbage N uptake from soil. For all grasslands and soil biota groups together, the model estimated 105% of the measured net herbage N uptake from soil. Soil biota production-ecological modelling is a powerful tool to understand and predict N uptake in grassland, reflecting the effects of previous manure management and soil type. The results show that combining production ecological modelling to predict N supply with existing soil N tests using aerobic incubation methods, can add to a scientifically based improvement of the N fertilisation recommendations for production grasslands.

Simultaneous Loss of Soil Biodiversity and Functions along a Copper Contamination Gradient: When Soil Goes to Sleep

The impact of biodiversity loss on soil functions is well established via laboratory experiments that generally consider soil biota groups in isolation from each other, a condition rarely present in field soils. As a result, our knowledge about anthropogenic-induced changes in biodiversity and associated soil functions is limited. We quantified an array of soil biological constituents (plants, earthworms, nematodes, bacteria, and fungi) to explore their interactions and to characterize their influence on various soil functions (habitat for soil organisms, air and water regulation, and recycling of nutrients and organic waste) along a legacy Cu pollution gradient. Increasing Cu concentrations had a detrimental impact on both plant growth and species richness. Belowground soil biota showed similar responses, with their sensitivity to elevated Cu concentrations decreasing in the order: earthworms > bacteria > nematodes > fungi. The observed loss of soil biota adversely affected natural soil bioturbation, aggregate formation and stabilization, and decomposition and mineralization processes and therefore resulted in compacted soil with narrow pore size distributions and overall smaller pores, restricted air and water storage and flow, and impeded C, N, and P cycling. The simultaneous evolution of soil biodiversity and functions along the Cu gradient emphasized the key role of soil life in controlling ecosystem services. Furthermore, results indicated that different soil biodiversity and functional indicators started to decline (10% loss) within a Cu concentration range of 110 to 800 mg total Cu kg−1.

Examination of the role of the microbial loop in regulating lake nutrient stoichiometry and phytoplankton dynamics

Abstract. The recycling of organic material through bacteria and microzooplankton to higher trophic levels, known as the "microbial loop", is an important process in aquatic ecosystems. Here the significance of the microbial loop in influencing nutrient supply to phytoplankton has been investigated in Lake Kinneret (Israel) using a coupled hydrodynamic–ecosystem model. The model was designed to simulate the dynamic cycling of carbon, nitrogen and phosphorus through bacteria, phytoplankton and zooplankton functional groups, with each pool having unique C : N : P dynamics. Three microbial loop sub-model configurations were used to isolate mechanisms by which the microbial loop could influence phytoplankton biomass, considering (i) the role of bacterial mineralisation, (ii) the effect of micrograzer excretion, and (iii) bacterial ability to compete for dissolved inorganic nutrients. The nutrient flux pathways between the abiotic pools and biotic groups and the patterns of biomass and nutrient limitation of the different phytoplankton groups were quantified for the different model configurations. Considerable variation in phytoplankton biomass and dissolved organic matter demonstrated the sensitivity of predictions to assumptions about microbial loop operation and the specific mechanisms by which phytoplankton growth was affected. Comparison of the simulations identified that the microbial loop most significantly altered phytoplankton growth by periodically amplifying internal phosphorus limitation due to bacterial competition for phosphate to satisfy their own stoichiometric requirements. Importantly, each configuration led to a unique prediction of the overall community composition, and we conclude that the microbial loop plays an important role in nutrient recycling by regulating not only the quantity, but also the stoichiometry of available N and P that is available to primary producers. The results demonstrate how commonly employed simplifying assumptions about model structure can lead to large uncertainty in phytoplankton community predictions and highlight the need for aquatic ecosystem models to carefully resolve the variable stoichiometry dynamics of microbial interactions.

Effects of dazomet on soil organisms and recolonisation of fumigated soil

Abstract Fumigation is a common practice to control soil pathogens, but little is known about the impacts of fumigation on other soil biota groups. The purpose of this study was to investigate the effects of fumigation on soil biota, including microorganisms, nematodes, and microarthropods. Bacteria were the most resistant group and some survived following treatment with 2000 mg kg −1 dazomet. Some soil fungi survived 100 mg kg −1 dazomet, although they were mainly Trichoderma . The fungi pathogenic to ginseng were all killed at 100 mg kg −1 , and showed both inter- and intra-species variation with respect to dazomet susceptibility. Among the nematodes, Aphelenchus was relatively resistant. The results suggested that susceptibility of soil organisms to dazomet differs between species, and that tolerant organisms may engage in recolonisation. In microcosm experiments, the microbial biomass and community were assessed using phospholipid fatty acid (PLFA) analysis while recolonisation of soil organisms was controlled by mesh size. The bacterial PLFA levels were changed little after fumigation, whereas the fungal PLFA levels gradually increased after fumigation. Principal analysis of the PLFA levels and the ratio of gram-negative to gram-positive bacteria showed that fumigation altered the microbial community. The number of nematodes did not recover even at 12 weeks after fumigation. The increased Collembolan numbers suggest that fumigated soil could be recolonised by specific organisms that have adapted to the conditions. In field experiments, we tested the ability of organic materials to enhance the recolonisation of fumigated soil by soil organisms. Bean powder and rice bran increased the microbial PLFA levels and nematode numbers at 6 weeks and 12 weeks after treatment, and the abundance of nematodes continued to increase 42 weeks after fumigation. The abundance of microarthropods was only slightly affected by the presence of the organic materials. We suggest that treating fumigated soils with organic materials is an effective technique to promote soil organism numbers. In addition, Trichoderma was observed to be relatively resistant to fumigation, and therefore, we propose that the fumigation effect can be improved by using a combination of resistant Trichoderma and dazomet.

ZONATION AND DENSITY OF INTERTIDAL COMMUNITIES AT COASTAL AREA OF BATU HIJAU, SUMBAWA

Characteristics of coastal tidal areas of Batu Hijau vary from sandy substrate type, sandy to rocky reef with a wide expanse of intertidal ranges from 100 meters to 350 meters. To find out zoning intertidal community,the observation conducted at five locations intertidal beach, each consisting of three zones: the high tide, middle tide and low tide. Living structure in tidal areas of coastal Batu Hijau, Sumbawa consists of the main communities and associated biota. The main intertidal community composed of coral, seagrass, algae, and other fauna, while the intertidal biota associated with tidal habitat consists of a group of molluscs, echinoderm, crustacean, worms and fish. Distribution of intertidal communities formed three zones consisting of (1) seagrass (21.3%) in the upper zone (high tide), (2) algae (35.5%) in the central zone (mid tide), and (3) coral (28.5%) and algae (42.5%) in the lower zone (low tide). The main groups of biota in the form of tidal zoning system consisting of two groups of molluscs (51.12%) in the upper zone, while the echinoderms that predominate in the central zone (36.96%) and lower (66.89%). No significant differences between the structure and composition of marine intertidal communities in September 2011 (rainy season) and April 2012 (dry season). Keywords: intertidal (tidal), percent cover, density, community, biota

ZONATION AND DENSITY OF INTERTIDAL COMMUNITIES AT COASTAL AREA OF BATU HIJAU, SUMBAWA

<p>Characteristics of coastal tidal areas of Batu Hijau vary from sandy substrate type, sandy to rocky reef with a wide expanse of intertidal ranges from 100 meters to 350 meters. To find out zoning intertidal community,the observation conducted at five locations intertidal beach, each consisting of three zones: the high tide, middle tide and low tide. Living structure in tidal areas of coastal Batu Hijau, Sumbawa consists of the main communities and associated biota. The main intertidal community composed of coral, seagrass, algae, and other fauna, while the intertidal biota associated with tidal habitat consists of a group of molluscs, echinoderm, crustacean, worms and fish. Distribution of intertidal communities formed three zones consisting of (1) seagrass (21.3%) in the upper zone (high tide), (2) algae (35.5%) in the central zone (mid tide), and (3) coral (28.5%) and algae (42.5%) in the lower zone (low tide). The main groups of biota in the form of tidal zoning system consisting of two groups of molluscs (51.12%) in the upper zone, while the echinoderms that predominate in the central zone (36.96%) and lower (66.89%). No significant differences between the structure and composition of marine intertidal communities in September 2011 (rainy season) and April 2012 (dry season).</p> <p><br /> Keywords: intertidal (tidal), percent cover, density, community, biota</p>

Response of fish and benthic invertebrate communities to constrained channel conditions in a mountain river: Case study of the Biała, Polish Carpathians

Abstract Following considerable hydromorphological degradation in past decades, the gravel-bed Biala River, Polish Carpathians, is to be restored through establishing erodible corridor in two river sections. In these sections, relatively long, unmanaged channel reaches alternate with short, channelized reaches located in the vicinity of bridges. Effects of the alternating morphologies on physical habitat conditions, fish and benthic invertebrate communities, and ecological river quality were investigated in 10 pairs of unmanaged and channelized cross-sections located between significant tributaries. Unmanaged cross-sections with an average of two low-flow channels exhibited significantly greater variation in depth-averaged and near-bed velocity and bed material size than single-thread, channelized cross-sections. Summer, autumn and winter surveys of benthic invertebrates indicated that the unmanaged cross-sections typically hosted three times more taxa than channelized cross-sections, and this was reflected in distinct appraisal of the two cross-section types by means of invertebrate-based BMWP-PL index. Electrofishing indicated no statistically significant difference in the number of fish species between both types of river cross-sections, and the resultant similar scores of the European Fish Index allowed both cross-section types to be associated with the same class of ecological river quality. This study indicated that short channelized river reaches do not disrupt continuity of fish populations, although they provide worse habitats for fish, reflected in the lower numbers of individuals, especially juveniles. It also highlighted the need of investigating various groups of river biota to determine the response of river biocoenosis to environmental stressors and evaluate the ecological status of the river.

Home-Field Advantage: A matter of interaction between litter biochemistry and decomposer biota

Home-Field Advantage (HFA) defines the way with which a plant litter may decompose faster in the habitat from which it derives (i.e. home) than beneath a different plant community (i.e. away from home). Recent studies, using plurispecific litter and involving several soil biota groups, failed to demonstrate a clear positive HFA effect. The interactions between different soil biota groups and different litter types may cause additive effect on decomposition process. Concomitantly, new hypothesis was raised which expects a continuum from positive to negative interactions between transplanted litter and host litter as both litters become increasingly dissimilar in quality, which has been called Substrate quality–Matrix quality Interaction (SMI). Against this background, we aimed at testing the influence of both litter quality and soil organisms in determining the HFA and the SMI hypothesis. We used reciprocal plurispecific transplanting litter along a gradient of litter quality with three successional stages: early (S1), medium (S2) and late successional stage (S3), coupled with litterbags of different mesh size to select different decomposers communities. Furthermore, we analyzed litter quality in order to test the SMI hypothesis. Overall, we did not observe a general HFA or SMI effect. In micromesh litterbags, only S1 litter showed an HFA effect (+7%) while in mesomesh litterbags, only S2 litter presented an HFA effect (+8%). The contribution of each litter quality fraction to the HFA index allowed us to show that only highly labile fractions (i.e., solubles and hemicellulose) presented a positive HFA index, independently of the mesh size. Indeed, our findings corroborated the SMI hypothesis but for labile fraction only. Finally, our results highlighted a strong inertia between different soil decomposer groups for the attack of the most recalcitrant biochemical fraction (i.e. lignin) only in late stage, independently of the litter origin.

Values and attitudes of the urban public towards peri-urban agricultural land

Peri-urban agricultural landscapes around the world are undergoing rapid transformation due to urban expansion. While some landscape values are being protected by current land-use planning frameworks, we know little about the broader values and attitudes of the urban public shaping this transformation. The structure of the values assigned to peri-urban agricultural landscapes by residents of Melbourne, Australia was explored and related to stated landscape preferences and people's underlying values. Exploratory factor analysis was used to categorise assigned values in multifunctional, food and native biota groups, and stated preferences for photographs into four landscape categories: intensive landscapes, extensive landscapes, high tree cover and plantations. The structure of underlying personal values closely resembled other studies of environmental value orientations. Multiple regression analysis revealed that preferences for all landscape categories were predicted strongly by multifunctional assigned values. Significant relationships were also evident between all assigned value groups and the biospheric underlying value orientation. Attitudes towards residential development approaches were also related significantly to assigned but not underlying values. Assigned values appear therefore to mediate between underlying values and attitudes towards peri-urban landscapes. This research demonstrates that peri-urban agricultural landscapes are perceived as multifunctional systems by the urban public and are valued for a range of functions not typically included in land use policies. This study also suggests that in the context of rapid land use change, a variety of landscape types should be retained on the urban fringe for their benefit to the urban public, and synergies promoted between landscape functions.

Impacts of inundation and drought on eukaryote biodiversity in semi‐arid floodplain soils

Floodplain ecosystems are characterized by alternating wet and dry phases and periodic inundation defines their ecological character. Climate change, river regulation and the construction of levees have substantially altered natural flooding and drying regimes worldwide with uncertain effects on key biotic groups. In southern Australia, we hypothesized that soil eukaryotic communities in climate change affected areas of a semi-arid floodplain would transition towards comprising mainly dry-soil specialist species with increasing drought severity. Here, we used 18S rRNA amplicon pyrosequencing to measure the eukaryote community composition in soils that had been depleted of water to varying degrees to confirm that reproducible transitional changes occur in eukaryotic biodiversity on this floodplain. Interflood community structures (3years post-flood) were dominated by persistent rather than either aquatic or dry-specialist organisms. Only 2% of taxa were unique to dry locations by 8years post-flood, and 10% were restricted to wet locations (inundated a year to 2weeks post-flood). Almost half (48%) of the total soil biota were detected in both these environments. The discovery of a large suite of organisms able to survive nearly a decade of drought, and up to a year submerged supports the concept of inherent resilience of Australian semi-arid floodplain soil communities under increasing pressure from climatic induced changes in water availability.

Residual Concentration of PAHs in Seafood from Hormozgan Province, Iran: Human Health Risk Assessment for Urban Population

This study is to determine the concentrations of sixteen poly aromatic hydrocarbons in eighteen pooled samples of fish, shrimp, crab and bivalve from markets of Hormozgan province, Iran. The poly aromatic hydrocarbon levels varied from 16 ± 8.4 to 28.18 ± 3.74 ng/g wet weight. The investigated samples were classified as minimally contaminated. Distribution patterns showed that PAHs with 4, 5 and 6 rings dominated, confirming the pyroge nic source of detected PAHs. Fish contributed more than other biota groups in transforming of PAHs to Hormozgan Province people. The average of B (a)P eq)values for the studied biota was 2.71 ± 2.28 ng/g that was greater than calculated local screen value. This finding was implemented in poor quality of studied biota and necessity for risk management.

About this title ‐ Early Palaeozoic Biogeography and Palaeogeography

The Early Palaeozoic was a critical interval in the evolution of marine life on our planet. Through a window of some 120 million years, the Cambrian Explosion, Great Ordovician Biodiversification Event, End Ordovician Extinction and the subsequent Silurian Recovery established a steep trajectory of increasing marine biodiversity that started in the Late Proterozoic and continued into the Devonian. Biogeography is a key property of virtually all organisms; their distributional ranges, mapped out on a mosaic of changing palaeogeography, have played important roles in modulating the diversity and evolution of marine life. This Memoir first introduces the content, some of the concepts involved in describing and interpreting palaeobiogeography, and the changing Early Palaeozoic geography is illustrated through a series of time slices. The subsequent 26 chapters, compiled by some 130 authors from over 20 countries, describe and analyse distributional and in many cases diversity data for all the major biotic groups plotted on current palaeogeographic maps. Nearly a quarter of a century after the publication of the ‘Green Book’ (Geological Society, London, Memoir 12, edited by McKerrow and Scotese), improved stratigraphic and taxonomic data together with more accurate, digitized palaeogeographic maps, have confirmed the central role of palaeobiogeography in understanding the evolution of Early Palaeozoic ecosystems and their biotas.

Palatability of carbonized materials to Collembola

Amendments with carbonized materials can improve soil carbon storage and fertility. While data on effects of such additions on soil properties or plant growth are becoming increasingly available, we do not yet know how carbonized materials affect key soil biota groups, such as Collembola. Hydrochar is one type of carbonized product, produced by hydrothermal carbonization, an alternative method to pyrolysis. The goal of this study was to examine the palatability of hydrochars to Collembola. As part of this study, we evaluated effects on palatability of different particle sizes, different types of hydrochar, and the effects of pre-washing the product. Finally, we analyzed the effect of hydrochar on fitness parameters such as molting, number of eggs, survivors and hatchlings of Collembola. We conducted all these laboratory tests using two different species Coecobrya tenebricosa (Folsom) Gruia and Folsomia fimetaria L. Both species were able to consume hydrochar, even though palatability was relatively low. Both species were able to complete their life cycle with hydrochar as the sole food source. Neither pre-washing, nor type and particle size of hydrochar significantly influenced palatability in the ranges of properties we examined. Our results suggest that these animals, since they can ingest these materials, can play an important role in the degradation and distribution of carbonized materials in soil.

Divergent consequences of hydrochar in the plant–soil system: Arbuscular mycorrhiza, nodulation, plant growth and soil aggregation effects

Establishment of a sustainable carbon sink by producing and adding carbonized materials to soils provides a promising way to reduce atmospheric CO2 concentrations and mitigate the progressing climate change. Production of hydrochars via hydrothermal carbonization represents an energy- and CO2-efficient method to carbonize biomass and also allows the usage of new feedstocks including wet materials (e.g. sewage sludge or other wet waste materials). There is a dearth of information on hydrochar effects on soil biota and plants, which is important to inform potential larger scale applications. Here we tested hydrochar derived from spent brewer's yeast in a greenhouse study with Medicago sativa and in a 5-month soil incubation study in order to examine its effects on plant growth, root symbionts (arbuscular mycorrhiza abundance and root nodulation) and, for the first time, on soil aggregation. We decided to wash the hydrochar material in order to separate adhering water soluble components resulting from the production process and used the resulting leachate as a separate treatment. In both studies, soil aggregation was positively influenced by addition of the hydrochar. However, in contrast to a previous study, this hydrochar had no positive effects on AM fungal abundance; in fact we found a clearly negative effect on AM-fungal root colonization especially when both, hydrochar and its leachate were applied. Conversely, increased rates of root nodulation were found. Clearly, biota groups diverged in their response to hydrochar; this needs to be considered in test designs. These results highlight that it is necessary to carefully test materials derived from hydrothermal carbonization before applying them at an agricultural scale in order to prevent negative effects on soil biota.

Agricultural intensification and de-intensification differentially affect taxonomic diversity of predatory mites, earthworms, enchytraeids, nematodes and bacteria

Agricultural intensification is known to impact the soil biota community. In a previous study, the impact of agricultural intensification on total abundances and functional group structure of major soil biota groups were measured. In this study we address the effects of conversion of extensively managed grassland to arable land on taxonomic diversity at genus and species level of four major soil biota groups (predatory mites, earthworms, enchytraeids, nematodes and bacteria). Vice versa, the effect of agricultural de-intensification (re-establishment of grassland on former arable land) on soil biota taxonomic diversity was also studied.Conversion of an extensively managed grassland to arable land had detrimental effects on taxonomic richness and diversity across taxonomic groups in the short-term, with largest effects on soil biota with larger body size. Effects of arable management were detrimental shortly after conversion. Restoration of grassland resulted in establishment of a species-rich community of nematodes (with partly different species), and recovery of the earthworm community. Predatory mite species were less successful in re-establishing and negative effects on enchytraeid species persisted.When combining the results of Postma-Blaauw et al. (2010) with the present study, we conclude that agricultural intensification resulted in a reduction in abundance and taxonomic diversity of nematodes and bacteria, whereas functional group structure of these groups was little affected. In contrast, predatory mites and earthworms were affected both in functional group structure and in taxonomic diversity. We conclude that agricultural intensification affects total abundances and taxonomic diversity of soil biota in agricultural land, but not necessarily the functional group diversity. Reduced taxonomic diversity may result in reduced resilience to stress, whereas reduced total abundances of microbiota may affect ecosystem functions such as nutrient mineralization.

Middle-Upper Miocene stratigraphy of the Taman Peninsula, Eastern Paratethys

AbstractThe stratigraphy of the Taman Peninsula is defined using the sections at Zelensky Hill — Panagia, Popov Kamen, Taman and Zheleznyi Rog. The stratigraphy is constructed from distribution of mollusks, foraminifers, nannofossils, diatoms, and organic-walled phytoplankton, as well as incorporating paleomagnetic data. The occurrence of oceanic diatom species in the Middle-Upper Sarmatian, Maeotian and Lower Pontian makes a direct correlation possible between the sections studied, the Mediterranean basin and oceanic zonation. The new data on planktonic and benthic biotic groups suggests a pulsating connection of the Eastern Paratethys with the open marine basins, especially during transitional intervals within constant environments. Comprehensive studies of the Chokrakian-Kimmerian microbiota provide evidence for several levels of marine microbiotic associations that are related to short-term marine invasions. The biotic and paleomagnetic data of the Taman Peninsula sections give a more comprehensive, but sometimes a controversial picture on the Eastern Paratethys history and the nature of its relationship with the adjacent marine basins.

Sward management influences fruiting of grassland basidiomycete fungi

The loss of semi-natural grasslands in Europe, largely though ploughing/reseeding and synthetic fertiliser inputs, has caused a severe reduction in the diversity and abundance of grassland macrofungi. Of these, it is the colourful members of the genus Hygrocybe spp. (waxcaps) that have received most conservation attention, with current management prescriptions recommending the avoidance of fertiliser additions and maintenance of a short sward. However, the latter recommendation is based solely on empirical observations and is at odds with management strategies aimed at the conservation of many other groups of biota. In order to test the effect of sward height on macrofungal fruiting, a field experiment was established at a grassland site known to contain diverse populations (>50 species) of grassland fungi. Replicated 80m2 plots (n=5) were subjected to mowing at 3cm or 8cm either from May or July onwards, as well as a late haycut to 3cm in September or no mowing at all. Macrofungal fruitbodies were counted in fortnightly surveys during the autumn. Species richness and fruitbody numbers were greatest on plots mown to 3cm, either continually or following a July haycut, with hardly any fruitbodies formed on uncut plots. Panaeolus acuminatus and Entoloma conferendum showed atypical responses, fruiting most prolifically on 8cm-cut and September-cut plots respectively. Thus haycutting followed by maintenance of a short sward, a regime also compatible with maintaining diversity of many grassland plants and invertebrates, is conducive to abundant fruiting of diverse grassland fungi. The formation of fruitbodies is important for wider appreciation of these fungi and useful for their routine monitoring but further information about below-ground mycelial dynamics is urgently required.

Predictors of fine-scale spatial variation in soil mite and microbe community composition differ between biotic groups and habitats

Soils support highly diverse communities, but due to the great spatial complexity at very fine scales and small size of soil organisms, our knowledge of what structures belowground communities remains limited. We used a spatially nested sampling regime (distances between samples of 0.06–122 m) to develop an understanding of the relationship between soil mite and microbial community composition and properties of vegetation and underlying soil within two habitats: birch woodland and heather moorland. We found that variation in community composition of all four biotic groups investigated (Oribatida, Mesostigmata, fungi and bacteria – thus representing multiple trophic levels) was related to variation in soil properties and vegetation, but also space. These three factors (i.e. vegetation, soil properties and space) accounted for 17–36% of the variation in community composition of the biotic groups. The remaining, rather large, proportion of unexplained variation in community composition (64–87%) is likely to represent either random variation or variation related to unmeasured variables that are not spatially auto-correlated. Soil properties generally explained more variance in belowground communities than could vegetation composition. This should not be interpreted as evidence that soil properties exert a greater influence on belowground communities than vegetation composition per se , as the vegetation composition within a habitat is likely to vary at a larger spatial scale than the soil properties we measured. Vegetation composition had stronger explanatory power in the birch woodland and was more strongly related to fungal community composition than that of any other biotic group, particularly in heather moorland. This relationship may reflect the strong association between plants and their fungal symbionts and pathogens. We conclude that both vegetation composition and variation in soil properties influence belowground communities. However, the relative importance of these two factors depends on both habitat and the type of organism being studied.

AGA President’s Symposium 2011: The Application of Genomics to Biodiversity

The 2011 President’s Symposium of the American Genetic Association was held in Guanajuato, Mexico, from July 23 through 26 with a focus on “Genomics and Biodiversity.” The meeting was a great success, with over 150 attendees from Mexico, United States, Brazil, Canada, Chile, Denmark, Germany, Scotland, and Spain. Over a third of the attendees were students. Sessions were held at the National Genomics Laboratory for Biodiversity (LANGEBIO), a state-of-the-art facility in nearby Irapuato, and at the Hotel Camino Real, a remodeled Spanish hacienda, in Guanajuato. The Latin ambience, including great food, song, and dance, and the rifts of different accents mixing with the more ubiquitous tones of our Mexican hosts were great backdrops to the scientific themes that had brought us together. This was only the second time the annual meeting of the AGA has ventured outside of the United States (the 2006 meeting was held in Vancouver, Canada). Throughout the meeting, participants were subtly reminded of the appeal of diversity, which is central to the mission of the AGA. The meeting environment was thoroughly enjoyable and stimulating thanks to the efforts of AGA President, Scott Edwards, and LANGEBIO Director, Luis Herrera Estrella, with assistance from the local event organizer, Emilio Bolanos, of Turismo & Convenciones and from Anjanette Baker, Managing Editor of Journal of Heredity. The substance of the meeting effectively captured the issues and ideas resonating through the burgeoning field of genomics, a unifying theme bridging the broad research interests of all AGA members. The speakers (Table 1) and poster presentations covered all major biotic groups and, importantly, demonstrated that recent advances in genomics of humans and model organisms of agricultural or biomedical interest have inspired application to a wide range of practical and theoretical questions in nonmodel species and natural environments. Table 1 Symposium speakers, with titles of their talks and institute affiliations. Talks that focused on humans included the search for signatures of selection in humans from different natural environments, the reconstruction of the population history of Latin America, and the complex history of evolution in early human species. Traditional plant models were represented in talks on advances in the study of maize, the examination of epigenetics of flower development, and the search for patterns of adaptation. Therese Markow’s talk on diversification in Drosophila, the most widely recognized model of insect genomics, demonstrated how the study of natural populations can be a powerful tool for understanding the genomic underpinnings of behavioral specializations and speciation events. Forays into new ecological/evolutionary questions using genomics and transcriptomics were also presented in several nonmodel organisms, including phylogenomics in pitcher plants, microbial environmental contamination, and rapid adaptation and speciation in cichlids. Perhaps the most comprehensive example of how animal model genomics can link to a broad range of questions in evolution and conservation was provided by Robert Wayne, the recipient of the Wilhelmine Key American Genetic Association Distinguished Lecture Award. In his inspiring presentation, Wayne showed how the domestic dog genome has enabled the development of resources that have unlocked many secrets of canid evolution, including the genetic basis of several phenotypic traits, the history of domestication, and genetic selection in wild populations. Finally, several talks emphasized the challenges and opportunities ahead. Although the diverse taxa discussed provided interesting examples of both natural and synthetic experimental systems, the talks demonstrated that in spite of the promise of genomics, most research areas are constrained by the very small number of genome-enabled species, especially in nonmammalian taxa. Together, these talks clearly demonstrated that genomics has begun to permeate many areas of biological enquiry. However, they also pointed to challenges that remain before genomics can have a full and wide-ranging impact on studies of biodiversity. These include the need for: 1) more genomic data from nonmodel species, 2) inexpensive population-level tools to extend the utility of basic genomic data, 3) increased training opportunities for students and established researchers in handling large databases, 4) further development of bioinformatic tools for large data sets (e.g., cloud computing, modular programming, etc.), 5) population-level sampling, with geo-referencing and documentation of associated phenotypic characters, and 6) quality genetic maps to more efficiently leverage information for genome-enabled species (e.g., candidate genes, single-nucleotide polymorphisms). Finally, there was the implicit recognition that describing and protecting biodiversity is an international concern, requiring strong international collaborations to be effective and to deal with the many associated cultural, environmental, and political issues. Most importantly, attendees were reminded that, despite new challenges, it is an exciting and rewarding time to be involved in the study and understanding of genomics and biodiversity.

Antarctic terrestrial biodiversity in a changing world

Recent analyses of Antarctic terrestrial biodiversity data, in combination with molecular biological studies, have created a new paradigm that long-term persistence and regional isolation are general features of most of the major groups of Antarctic terrestrial biota, overturning the previously widely assumed view of a generally recent colonisation history. This paradigm, as well as incorporating a new and much longer timescale in which to consider the evolution and adaptation of Antarctic terrestrial biota, opens important new cross-disciplinary linkages with geologists and glaciologists seeking to unravel the history of the continent itself. This unique biota now faces the twin challenges of responding to the complex processes of climate change facing some parts of the continent, and the direct impacts associated with human occupation and activity. In many instances, this biota is likely to benefit, initially at least, from the current environmental changes, and there is an expectation of increased production, biomass, population size, community complexity, and colonisation. However, the impacts of climate change may themselves be outweighed by other, direct, impacts of human activities, and in particular, the introduction of non-indigenous organisms from which until recently the terrestrial ecosystems of the continent have been protected. The Antarctic research community and those responsible for governance under the Antarctic treaty system are faced with the pressing challenges of (1) ensuring there is sufficient baseline monitoring and survey activity to enable identification of these changes, however caused and (2) ensuring that effective operational management and biosecurity procedures are in place to minimise the threat from anthropogenic activities.