Community structure and functional roles of meiofauna in the North Sea

Knowiedge on community structure of North Sea meiofauna has greatly increased recently. A quasisynoptic picture of meiofauna densities and copepod community structure from 171 stations of the southern North Sea, sampled in April–May 1986, has been obtained during the North Sea Benthos Survey. Latitudinal patterns in meiofauna abundance and copepod weight, abundance and diversity exist in an area between 51°30′N and 58°30′N. Using TWINSPAN-classification five major groups of copepod species can be recognized which are related to sediment type, latitude and depth. The part of the meiofauna in total benthic energy flow, their role in the benthic food web and in biogeochemical cycles is discussed based on existing literature. There are still considerable gaps in knowledge and the field is not progressing rapidly. Publication no. 599 Netherlands Institute of Ecology, Centre for Estuarine and Coastal Ecology, Yerseke, The Netherlands.     

Projecting terrestrial biodiversity intactness with GLOBIO 4

Scenario‐based biodiversity modelling is a powerful approach to evaluate how possible future socio‐economic developments may affect biodiversity. Here, we evaluated the changes in terrestrial biodiversity intactness, expressed by the mean species abundance (MSA) metric, resulting from three of the shared socio‐economic pathways (SSPs) combined with different levels of climate change (according to representative concentration pathways [RCPs]): a future oriented towards sustainability (SSP1xRCP2.6), a future determined by a politically divided world (SSP3xRCP6.0) and a future with continued global dependency on fossil fuels (SSP5xRCP8.5). To this end, we first updated the GLOBIO model, which now runs at a spatial resolution of 10 arc‐seconds (~300 m), contains new modules for downscaling land use and for quantifying impacts of hunting in the tropics, and updated modules to quantify impacts of climate change, land use, habitat fragmentation and nitrogen pollution. We then used the updated model to project terrestrial biodiversity intactness from 2015 to 2050 as a function of land use and climate changes corresponding with the selected scenarios. We estimated a global area‐weighted mean MSA of 0.56 for 2015. Biodiversity intactness declined in all three scenarios, yet the decline was smaller in the sustainability scenario (?0.02) than the regional rivalry and fossil‐fuelled development scenarios (?0.06 and ?0.05 respectively). We further found considerable variation in projected biodiversity change among different world regions, with large future losses particularly for sub‐Saharan Africa. In some scenario‐region combinations, we projected future biodiversity recovery due to reduced demands for agricultural land, yet this recovery was counteracted by increased impacts of other pressures (notably climate change and road disturbance). Effective measures to halt or reverse the decline of terrestrial biodiversity should not only reduce land demand (e.g. by increasing agricultural productivity and dietary changes) but also focus on reducing or mitigating the impacts of other pressures.     

Future hotspots of terrestrial mammal loss

Current levels of endangerment and historical trends of species and habitats are the main criteria used to direct conservation efforts globally. Estimates of future declines, which might indicate different priorities than past declines, have been limited by the lack of appropriate data and models. Given that much of conservation is about anticipating and responding to future threats, our inability to look forward at a global scale has been a major constraint on effective action. Here, we assess the geography and extent of projected future changes in suitable habitat for terrestrial mammals within their present ranges. We used a global earth-system model, IMAGE, coupled with fine-scale habitat suitability models and parametrized according to four global scenarios of human development. We identified the most affected countries by 2050 for each scenario, assuming that no additional conservation actions other than those described in the scenarios take place. We found that, with some exceptions, most of the countries with the largest predicted losses of suitable habitat for mammals are in Africa and the Americas. African and North American countries were also predicted to host the most species with large proportional global declines. Most of the countries we identified as future hotspots of terrestrial mammal loss have little or no overlap with the present global conservation priorities, thus confirming the need for forward-looking analyses in conservation priority setting. The expected growth in human populations and consumption in hotspots of future mammal loss mean that local conservation actions such as protected areas might not be sufficient to mitigate losses. Other policies, directed towards the root causes of biodiversity loss, are required, both in Africa and other parts of the world.     

Maternal transmission of risk for atherosclerosis

PURPOSE OF REVIEW: In the last 20 years, an increasing amount of epidemiological and pathological evidence has become available illustrating the relationship between an adverse in-utero environment and increased risk of vascular disease in the offspring. It is now generally accepted that epigenetic phenomena, such as either DNA methylation or chromatin modifications or both mediate the long-term memory and thus developmental programming of cells and tissues. RECENT FINDINGS: In utero, the placenta and fetus are exposed to the metabolic, antioxidant and pro-inflammatory and anti-inflammatory signals from the mother and will likely respond specifically. In the fetus, these responses may lead to permanent changes either in DNA methylation or chromatin modification or both and these changes may lead to increased atherosclerosis susceptibility in adulthood. However, the molecular mechanisms responsible for the translation of an adverse maternal environment into permanent epigenetic changes are poorly understood. SUMMARY: In this review, we briefly summarize the possible signals crossing the placental barrier and discuss the molecular mechanisms of epigenetic programming in the developing fetus leading to increased athero-susceptibility of the vessel wall.     

Suppressor of cytokine signaling 3 in the human hypothalamus

In rodents, the mediobasal hypothalamus and the hypothalamic paraventricular nucleus (PVN) are implicated in leptin signaling. Surprisingly little data is available on the human hypothalamus. We set out to study the expression of suppressor-of-cytokine-signaling 3 (SOCS3), α-melanocyte stimulating hormone (αMSH) and agouti-related protein (AgRP) in the infundibular nucleus (IFN) and to investigate the relationship between these neuropeptide expressions and serum leptin concentrations in a blood sample taken within 24h before death. We studied post-mortem human brain material by means of quantitative immunocytochemistry. We found that SOCS3 immunoreactivity was widely distributed throughout the hypothalamus, and most prominent in the PVN, whereas expression levels in the IFN were low. Surprisingly, SOCS3 expression in the PVN was inversely related to serum leptin. A significant positive correlation was observed between AgRP and NPY expression in the IFN. The inverse correlation between SOCS3 expression in the PVN and serum leptin was unexpected and may be related to the hypothalamic adaptation to fatal illness rather than to nutritional status, or may represent an interspecies difference.     

Macroinvertebrates as bioindicators of water quality in the Mkondoa River,Tanzania, in an agricultural area

The suitability of using macroinvertebrates as bioindicators of stream water quality was tested in the Mkondoa River in an agricultural area at Kilosa, using the rapid bioassessment protocol. The family biotic index (FBI) showed marked variation in water quality along the stream from values ranging from 4.1 to 5.0 in the upstream reaches, indicating good water quality, 5.3 to 5.5 in the mid-reaches and 6.0 to 6.5 in the lower reaches. The water quality index (WQI) indicated that water quality was fair (77 ± 0.98) in the upstream reach of the Mkondoa, marginal (55 ± 0.86) in the midstream reach and poor (33 ± 0.45) in the downstream reach. There were significant relationships between biological oxygen demand and dissolved oxygen and the occurrence of specific taxa, mainly Chironomus and Caenis. Significant changes in macroinvertebrate abundance were mostly related to changes in water quality. As in other parts of the world, macroinvertebrate communities proved to be good biological indicators of water quality and they should be used as bioindicators in long-term monitoring of this river.     

Myosin light-chain expression during avian muscle development

Monoclonal antibodies to adult chicken myosin light chains were generated and used to quantitate the types of myosin light-chain (MLC) isoforms expressed during development of the pectoralis major (PM), anterior latissimus dorsi (ALD), and medial adductor (MA) muscles of the chicken. These are muscles which, in the adult, are composed predominantly of fast, slow, and a mixture of fiber types, respectively. Three distinct phases of MLC expression characterized the development of the PM and MA muscles. The first identifiable pase occurred during the period of 5-7 d of incubation in ovo. Extracts of muscles from the pectoral region (which included the presumptive PM muscle) contained only fast MLC isoforms. This period of exclusive fast light-chain synthesis was followed by a phase (8- 12 d of incubation in ovo) in which coexpression of both fast and slow MLC isoforms was apparent in both PM and MA muscles. During the period, the composition of both fast and slow MLC isoforms in the PM and MA muscles was identical. Beginning at day 12 in ovo, the ALD was also subjected to immunochemical analyses. The proportion of fast and slow MLCs in this muscle at day 12 was similar to that present in the other muscles studied. The third development phase of MLC expression began at approximately 12 d of incubation in ovo and encompassed the transition in MLC composition to the isoform patterns incubation in ovo and encompassed the transition in MLC composition to the isoform patterns typical of adult muscle. During this period, the relative proportion of slow MLC rose in both the MA and ALD and fell in the PM. By day 16, the third fast light chain, LC(3f), was apparent in extracts of both the PM and MA. These results show that there is a developmental progression in the expression of MLC in the two avian muscles studied from day 5 in ovo; first, only fast MLCs are accumulated, then both fast and slow MLC isoforms are expressed. Only during the latter third of development in ovo is the final MLC isoform pattern characteristic of a particular muscle type expressed.     

Determining alternative models for vegetation response analysis: a non-parametric approach

Abstract. Vegetation models based on multiple logistic regression are of growing interest in environmental studies and decision making. The relatively simple sigmoid Gaussian optimum curves are most common in current vegetation models, although several different other response shapes are known. However, improvements in the technical means for handling statistical data now facilitate fast and interactive calculation of alternative complex, more data-related, non-parametric models. The aim in this study was to determine whether, and if so how often, a complex response shape could be more adequate than a linear or quadratic one. Using the framework of Generalized Additive Models, both parametric (linear and quadratic) and non-parametric (smoothed) stepwise multiple logistic regression techniques were applied to a large data set on wetlands and water plants and to six environmental variables: pH, chloride, orthophosphate, inorganic nitrogen, thickness of the sapropelium layer and depth of the water-body. All models were tested for their goodness-of-fit and significance. Of all 156 generalized additive models calculated, 77 % were found to contain at least one smoothed predictor variable, i.e. an environmental variable with a response better fitted by a complex, non-parametric, than by a linear or quadratic parametric curve. Chloride was the variable with the highest incidence of smoothed responses (48 %). Generally, a smoothed curve was preferable in 23 % of all species-variable correlations calculated, compared to 25 % and 18 % for sigmoid and Gaussian shaped curves, respectively. Regression models of two plant species are presented in detail to illustrate the potential of smoothers to produce good fitting and biologically sound response models in comparison to linear and polynomial regression models. We found Generalized Additive Modelling a useful and practical technique for improving current regression-based vegetation models by allowing for alternative, complex response shapes.     

Calibrating Ellenberg indicator values for moisture,acidity, nutrient availability and salinity in the Netherlands

A general calibration of Ellenberg indicator values for moisture, acidity, nutrient availability and salinity was carried out on a large database of relevées and environmental variables from a variety of ecosystems in the Netherlands.Satisfying relationships with Ellenberg indicator values for moisture, acidity and salinity were found for mean groundwater level in spring time, soil pH and chloride concentration in groundwater. For mean groundwater level in spring and chloride concentration in groundwater subdivision of the database led to clearer relationships with indicator values. For the Ellenberg indicator value for nutrient availability satisfying calibration results were only achieved with data on standing crops and N stock in standing crop. The relationship with soil chemical variables was less clear.Although the correlation between indicator and measured values is obvious, the variation around the regression lines is considerable. However, because of the size and composition of the database, it is unlikely that our calibration results can be much improved by adding more (Dutch) data.The calibration results will be applied in the multi-stress model SMART-MOVE, developed to predict changes in species composition due to acidification, eutrophication and the effects of lowering groundwater.     

Attack of the clones: Population genetics reveals clonality of Colletotrichum lupini,the causal agent of lupin anthracnose

Colletotrichum lupini, the causative agent of lupin anthracnose, affects lupin cultivation worldwide. Understanding its population structure and evolutionary potential is crucial to design successful disease management strategies. The objective of this study was to employ population genetics to investigate the diversity, evolutionary dynamics, and molecular basis of the interaction of this notorious lupin pathogen with its host. A collection of globally representative C. lupini isolates was genotyped through triple digest restriction site-associated DNA sequencing, resulting in a data set of unparalleled resolution. Phylogenetic and structural analysis could distinguish four independent lineages (I–IV). The strong population structure and high overall standardized index of association (r̅_d) indicates that C. lupini reproduces clonally. Different morphologies and virulence patterns on white lupin (Lupinus albus) and Andean lupin (Lupinus mutabilis) were observed between and within clonal lineages. Isolates belonging to lineage II were shown to have a minichromosome that was also partly present in lineage III and IV, but not in lineage I isolates. Variation in the presence of this minichromosome could imply a role in host–pathogen interaction. All four lineages were present in the South American Andes region, which is suggested to be the centre of origin of this species. Only members of lineage II have been found outside South America since the 1990s, indicating it as the current pandemic population. As a seedborne pathogen, C. lupini has mainly spread through infected but symptomless seeds, stressing the importance of phytosanitary measures to prevent future outbreaks of strains that are yet confined to South America.