The assessment of biodiversity loss over time: wild legumes in Syria

The conservation community has been set a considerable challenge by way of the CBD (Convention on Biological Diversity) 2010 targets. This may not be achievable by 2010 as demanded by the CBD, but at least methodologies can be assessed with a view to their implementation, so that loss of biodiversity and its inherent genetic diversity can be reduced post 2010. There is therefore a need to develop and implement protocols to efficiently measure genetic erosion and to make the identification of the drivers of erosion clear enabling counter-measures to be taken. In this paper the applicability of the indirect genetic erosion threat assessment for wild populations of rare and endemic Vicia species has been investigated. The method applied was based on the scoring of 18 factors perceived to be threats in the 18 study sites in two regions of Syria. Both temporal and spatial patterns of genetic erosion were considered. The method clearly detected spatial patterns of threat, enabling discrimination between the study sites located in the two study regions. However, no significant variation among the sites within each region was detected, highlighting the restricted spatial resolution of the method. Most importantly the results were in agreement with population demographic change observed, confirmed by a highly significant correlation between the erosion threat score and the relative population size change over the last 20 years. The results confirm the great potential of indirect genetic erosion threat assessment in routine evidence-based wild plant conservation decision-making.     

National inventories of crop wild relatives and wild harvested plants: case-study for Portugal

Crop wild relatives (CWR) and wild harvested plant species (WHP) constitute an important element of a nation’s plant genetic resources (PGR) available for utilisation. Although their natural populations are threatened like other wild species by habitat lost and fragmentation, little attention has generally been paid to their systematic conservation. The development of checklists and inventories is considered by the convention on biological diversity (CBD) and the global strategy for plant conservation (GSPC) as the first step in any national strategy for conservation and sustainable use of plant diversity. Methodological approaches to the development of a national inventory of wild PGR are discussed in the light of a case-study for the CWR and WHP growing in mainland Portugal. The resultant inventory comprises 2319 taxa, of which 97.5% are CWR, 21.4% are WHP and 19.0% are both CWR and WHP. Approximately 6.1% are endemic to mainland Portugal; 24.1% occur in 1 to 4 Portuguese administrative regions; 15.6% are threatened, but only 5.9% are covered by legislative protection. Taxonomic misalignments and the dispersed nature of biological literature were the major impediments to the production of the national inventory, but once the inventory was established it has proven to be a powerful tool in conservation management.     

Geostatistical hierarchical model for temporally integrated radon measurements

In the search for important determinants of disease, epidemiologists often face the challenging task of retrospectively estimating exposures of interest. Such is the case in modern studies of the lung cancer risk posed by residential radon—a naturally occurring radioactive gas. Assessment of past radon exposures is limited because measurements are not generally available for the locations at which study subjects spent time prior to enrollment. In such settings, there is a need for prediction at unmeasured geopraphic sites and time periods. We develop a hierarchical Bayesian goestatistical model for predicting unmeasured radon concentrations over space and time. Our work arises from a study of residential radon in Iowa, where measurements were taken as yearly averages and subject to detector measurement error. Much attention has been given lately to geostatistical methods for data that are obtained as integrated averages over geographic regions. We show how these techniques work in the time domain as well. Unlike the numerical approximations that are needed to integrate over geographic regions, we are able to provide closed-form solutions for the integration that must be performed over temporal periods. Our approach is illustrated with radon concentrations measured from 614 different geographic sites and 799 time periods.     

Fatty acid composition of yak (Bos grunniens) cheese including conjugated linoleic acid and trans-18:1 fatty acids

The esterified fatty acid composition of cheese (YC) from yak ( Bos grunniens), reared in the highlands of the Nepalese Himalayas, was studied using capillary gas-liquid chromatography and compared with that of dairy cow Cheddar cheese (DC) purchased in a local market. The YC was collected from Dolakha, Nepal. The YC had a lower (P<0.001) myristic acid (C14:0; 6.7 vs 10.3%, YC vs DC, respectively) and palmitic acid content (C16:0; 23.3 vs 29.2%, YC vs DC, respectively) compared to DC. The YC had a lower (P<0.01) total medium-chain saturated fatty acids (C10:0-C16:0) content compared to DC (36.7 vs 47.3%, YC vs DC, respectively). On the other hand, the YC had a 24.8% higher (P<0.01) level of total long-chain saturated fatty acids (C17:0-C26:0) and a 3.2 times higher (P<0.001) content of total n-3 PUFA than DC. The ratio of n-3 PUFA to n-6 PUFA in YC was 0.87 compared to 0.20 in DC. YC had a 2.8 times higher (P<0.001) total trans-18:1 (9.18 vs 3.31%, YC vs DC, respectively) content. The percentage of vaccenic acid ( trans-11-C18:1) in YC was 4.6 times higher (6.23 vs 1.35% of total fatty acids, YC vs DC, respectively) than in DC. Vaccenic acid constituted 67.9% of total trans-C18:1 in YC. The Delta9-desaturase index for YC was lower than that of DC. The total conjugated linoleic acid (CLA) content in YC was 2.3% of total fatty acids compared to 0.57% in DC. The cis-9, trans-11 CLA isomer in YC constituted 88.5% of the total CLA. The results suggest that cheese from yak, grazed on Himalayan alpine pastures, may have a more healthful fatty acid composition compared to cheese manufactured from dairy cattle fed grain-based diets.     

Release of plant-available silicon from various silicon-rich amendments into soil solutions and leachates

Journal of Soils and Sediments - This study assessed the efficacy of selected silicon-rich soil amendments in terms of their ability to provide dissolved silicon (Si) to soil solutions during a...     

Suspended matter and associated contaminants in Danish streams: a national analysis

Purpose

Suspended matter (SM) in streams is usually considered of minor importance in Danish environmental management. However, SM has some ecological effects as it may (1) clog fish spawning grounds and (2) act as an important agent for transport and exposure of biota to chemical substances, such as phosphorus and toxic inorganic (e.g. heavy metals) and organic (e.g. pesticides) substances.

Materials and methods

A large national data set of >?100,000 water samples analysed for SM and loss on ignition was investigated for spatial concentration patterns, sediment yields and temporal trends. Moreover, the importance of SM as a transport agent for phosphorus and heavy metals in streams was investigated through a correlation analysis.

Results and discussion

The mean suspended matter concentration (SMC) (including organic matter) amounted to 12 mg l^?1, with an organic content of 4.9 mg l^?1 (41%). A clear difference in SMC temporal trends over the sampling period was found between geographical regions. Sediment yields were calculated for all major catchments revealing low sediment yields (1–15 t km^?2 year^?1) compared to neighbouring countries and showed clear geographical patterns. Statistically significant relationships were established between SMCs, suspended sediment concentrations (SSCs) (excluding organic matter) and organic matter concentrations (OMCs) and particulate phosphorus (PP) concentrations, and again spatial patterns appeared. However, it was clearly shown that SMC/SSC/OMC could not be used as a robust, nationwide, indicator for PP concentrations. Analyses of the relationship between SMC and particle-bound heavy metal concentrations generally revealed weak correlations except for Pb and Ni (median R²?>?0.3).

Conclusions

Relatively low SM concentrations and sediment yields were found. SM is, in some geographical regions, an important transport agent for PP. Clear geographical patterns occurred in the relationships between SMC/SSC/OMC and both river water discharge and PP, as well as for sediment yields and for temporal trends in SMC.

     

The impact of soil structure on the establishment of winter wheat (Triticum aestivum)

Soil physical properties affect the establishment of crops; these properties are influenced by cultivation employed during seedbed preparation and vary greatly depending upon the intensity of cultivations. However, there is little quantified data concerning the influence of cultivation on the precise soil structural arrangement of the seedbed and the effects of this on crop establishment. The dynamics of soil structure at the meso-scale (10–1000 μm), on a range of seedbeds and how they relate to crop establishment are considered in this paper. Significant interactions between cultivation techniques including soil structural properties and the interaction with crop establishment were identified. The relationship between soil structure and crop establishment was highly significant, with increased pore space reducing final establishment numbers. An improvement to a previous model (soil quality of establishment (SQE)) was developed following the addition of soil structural properties, accounting for an improved predictability of 14% of the variation across soil texture (sandy loam and clay loam) from ca. 56% to ca. 70%.     

The Economics of Intensifying Catfish Production: A Production Function Analysis1

Yields of channel catfish in the United States have increased as a result of higher levels of stocking, feeding and aeration. A Cobb-Douglas production function was estimated using survey data from 66 catfish ponds in West-Central Alabama to determine if further intensification of catfish production in West-Central Alabama would be profitable. Feed, capital, stocking rate, and length of production period explained most of the variation in yield. Values of the marginal products for feed, stocking rate and capital were consistently higher than input costs during the study period. Profit-maximizing levels of input use were higher than the levels of inputs used in West-Central Alabama during the study period. Results indicated that more intensive use of production inputs would increase yield and profits. However, careful interpretation of these results requires consideration of non-profit factors such ns cash Row and risk as well as the specific nature of the data used to develop the production relationship. The method utilized in this study can generally be applied to any aquaculture production system, but the recommendation for more intensive input use is specific to the pond data collected for this study.     

Larval Lobster (Homarus americanus Milne Edwards) Development with Great Salt Lake, Utah and Reference I Strains of Artemia Nauplii

Lobster larvae were reared on a diet of unfed Artemia nauplii from either Great Salt Lake, Utah, USA (harvested in late 1981), or from the Artemia Reference Center, Ghent, Belgium. The two strains produced equivalent survival, development, and growth rates in the experimental animals. Success at metamorphosis for lobsters fed each strain was high despite observations in the literature that other larvae which experience a pronounced metamorphosis could show high mortalities when fed Utah Artemia . The results indicate that either temporal variability in nutritional value of Utah Artemia can alter growth patterns of predaceous lanae or that larval lobsters have appropriate metabolic mechanisms to overcome dietary deficiencies previously associated with Utah Artemia .