Inter-year differences in survival of Atlantic puffins Fratercula arctica are not associated with winter distribution

Miniature geolocator loggers (Global Location Sensing, GLS) that provide daily locations of birds have revolutionised the study of winter ecology and migration patterns of seabirds. A long-term study of ringing recoveries and analyses of heavy metals and pollutants in tissues of Atlantic puffins Fratercula arctica from the Isle of May, south-east Scotland, suggested that this population wintered mainly within the North Sea. However, deployment of GLS devices over the 2007/2008 winter showed that many breeding birds made major excursions into the east Atlantic. This winter was the second of two when survival was extremely low (survival in 2006/2007 and 2007/2008 was 0.696 and 0.695, respectively, compared to the average of 0.922 over the period 1984/1985–2005/2006). These low rates of survival suggested that the unexpected use of the Atlantic might have been associated with unusually poor conditions in the North Sea as indicated by very low breeding success in 2007. Survival rate returned to previous levels in 2008/2009 providing the opportunity to test whether higher survival was associated with birds remaining in the North Sea, or whether movements into the Atlantic are a feature of this population unrelated to survival. Accordingly, geolocators were deployed over the 2009/2010 winter when adult survival was subsequently established to be high (0.913). We found greater support for the hypothesis that winter distribution is not associated with survival. Thus, 8 (40 %) of 20 individuals followed in 2009/2010 went into the Atlantic, a rate not significantly different from 11 (58 %) of the 19 followed in the 2007/2008 winter. Indeed, birds actually spent longer in the Atlantic and used a wider variety of areas in 2009/2010, although the time spent away from the colony was significantly shorter than in 2007/2008. Since our data were from individuals that survived, remaining in or moving out of the North Sea can both be successful strategies during winters when the population as a whole shows either high or low survival rates. Unfortunately, we do not know where birds that died had gone, and hence, the relative survival of birds that did or did not move into the Atlantic. Determining the link between survival and wintering area for any seabird remains a formidable challenge and will have to await the development of technologies that can determine both where and when birds die.     

Frequent colony fusions provide opportunities for helpers to become reproductives in the termite Zootermopsis nevadensis

In many termite taxa, colonies occupying the same nesting resource can meet, interact, and merge with unrelated conspecific neighbors. Because proto-termite ancestors likely also co-inhabited resources and experienced interactions with neighboring conspecific families, extant species that form fused colony units may offer fundamental clues to explaining the origins of eusociality in Isoptera, particularly if both original families retain the potential for reproduction. We allowed entire colonies of Zootermopsis nevadensis (Archotermopsidae) to interact, merge, and develop in the lab, then used genetic markers to determine the family of origin of reproductives, soldiers, and helpers. Persisting and new members of all castes arose from both original colonies and in some cases were hybrids of the two original lineages. We also measured the frequency of mixed-family colonies in natural settings. Ten out of 30 field sampled colonies contained mixed families, demonstrating that interactions and fusions are common in nature. We discuss the implications of our findings as a model system for understanding the evolution of eusociality in termites, highlighting the importance of ecological circumstances impacting direct, indirect, and colony-level fitness.     

Comment on “Use of local tidal records to identify relative sea level change: accuracy and error for decision makers” by Powell VA, McGlashan DJ, Duck RW (2012) J Coast Conserv

In this Comment we refer to our strong reservations concerning the paper by Powell et al. J Coast Conserv, (2012) recently published on the Online First web site of the Journal of Coastal Conservation. The paper makes a number of comments on data obtained from the Permanent Service for Mean Sea Level (PSMSL) and British Oceanographic Data Centre (BODC) which are incorrect or misleading. In addition, some of their comments on sea-level science in general need to be challenged and corrected.     

Two neighborhood-free plot designs for adaptive sampling of forests

Adaptive cluster sampling (ACS) has the potential of being superior for sampling rare and geographically clustered populations. However, setting up an efficient ACS design is challenging. In this study, two adaptive plot designs are proposed as alternatives: one for fixed-area plot sampling and the other for relascope sampling (also known as variable radius plot sampling). Neither includes a neighborhood search which makes them much easier to execute. They do, however, include a conditional plot expansion: at a sample point where a predefined condition is satisfied, sampling is extended to a predefined larger cluster-plot or a larger relascope plot. Design-unbiased estimators of population total and its variance are derived for each proposed design, and they are applied to ten artificial and one real tree position maps to estimate density (number of trees per ha) and basal area (the cross-sectional area of a tree stem at breast height) per hectare. The performances—in terms of relative standard error (SE%)—of the proposed designs and their non-adaptive alternatives are compared. The adaptive plot designs were superior for the clustered populations in all cases of equal sample sizes and in some cases of equal area of sample plots. However, the improvement depends on: (1) the plot size factor; (2) the critical value (the minimum number of trees triggering an expansion); (3) the subplot distance for the adapted cluster-plots, and (4) the spatial arrangement of the sampled population. For some spatial arrangements, the improvement is relatively small. The adaptive designs may be particularly attractive for sampling in rare and compactly clustered populations with critical value of 1, subplot distance equal to the diameter of initial circular plots, or plot size factor of 2.5 for an initial basal area factor of 2.     

Moderate seawater acidification does not elicit long-term metabolic depression in the blue mussel Mytilus edulis

Marine organisms are exposed to increasingly acidic oceans, as a result of equilibration of surface ocean water with rising atmospheric CO₂ concentrations. In this study, we examined the physiological response of Mytilus edulis from the Baltic Sea, grown for 2 months at 4 seawater pCO₂ levels (39, 113, 243 and 405 Pa/385, 1,120, 2,400 and 4,000 μatm). Shell and somatic growth, calcification, oxygen consumption and \textNH₄ ⁺ {\text{NH}}_{4}^{ + } excretion rates were measured in order to test the hypothesis whether exposure to elevated seawater pCO₂ is causally related to metabolic depression. During the experimental period, mussel shell mass and shell-free dry mass (SFDM) increased at least by a factor of two and three, respectively. However, shell length and shell mass growth decreased linearly with increasing pCO₂ by 6–20 and 10–34%, while SFDM growth was not significantly affected by hypercapnia. We observed a parabolic change in routine metabolic rates with increasing pCO₂ and the highest rates (+60%) at 243 Pa. \textNH₄ ⁺ {\text{NH}}_{4}^{ + } excretion rose linearly with increasing pCO₂. Decreased O:N ratios at the highest seawater pCO₂ indicate enhanced protein metabolism which may contribute to intracellular pH regulation. We suggest that reduced shell growth under severe acidification is not caused by (global) metabolic depression but is potentially due to synergistic effects of increased cellular energy demand and nitrogen loss.     

Feeding ecology and niche segregation in oceanic top predators off eastern Australia

We examined the feeding ecology and niche segregation of the ten most abundant fish species caught by longline operations off eastern Australia between 1992 and 2006. Diets of 3,562 individuals were examined. Hook timer data were collected from a further 328 fish to examine feeding behaviour in relation to depth and time of day. Prey biomass was significantly related to predator species, predator length and year and latitude of capture. Although the fish examined fed on a mix of fish, squid and crustacea, fish dominated the diet of all species except small albacore (Thunnus alalunga) which fed mainly on crustacea and large swordfish (Xiphias gladius) and albacore which fed mainly on squid. Cannibalism was observed in lancetfish (Alepisaurus spp.). Multidimensional scaling identified three species groups based on their diet composition. One group consisted of yellowfin tuna (T. albacares), striped marlin (Tetrapturus audax) and dolphinfish (Coryphaena hippurus); a second group consisted of bigeye tuna (T. obesus), swordfish and albacore; and a third consisted of southern bluefin tuna (T. maccoyii) and blue shark (Prionace glauca). Of note was the separation of mako shark (Isurus oxyrhynchus) and lancetfish from all other predators. Prey length generally increased with increasing predator length although even large predators fed on a wide range of prey lengths including very small prey. Overall, differences in prey type and size, feeding times and depths were noted across the range of species examined to the extent that predators with overlapping prey, either in type or size, fed at different times of the diel period or at different depths. Taken together these data provide evidence for feeding niche segregation across the range of oceanic top predators examined.     

Performance and suitability of a landfill bioreactor with low cost biofilm contained clay-waste polyethylene-clay composite liner system for tropical climates of Asian countries

The objective of the study was to develop a low cost and environmentally friendly liner system for a landfill bioreactor to harness energy from waste. The landfill bioreactor test cell was constructed and evaluated for performance under dry tropical conditions of Sri Lanka. The research was carried out from March 2009 to September 2010. The clay-waste polyethylene-clay composite liner system was developed and permeability was tested. The permeability values of the liner under both saturated and unsaturated conditions at the high estimated hydraulic head of 86.2 cm were in between 6.3 × 10⁻⁸ and 2.6 × 10⁻⁸ cm/s. The permeability of the liner under waste filled condition varied between 2.17 × 10⁻⁹ and 8.15 × 10⁻⁹ cm/s, which satisfies the standard permeability value. Thus, the results were below the minimum requirement at very high estimated leachate head. After loading the test cell, leachate and permeate characteristics were analyzed for 273 days, from January 2010 to September 2010. The study showed the relationships among various parameters including pH, electrical permeability, chemical oxygen demand, biological oxygen demand, ammonia, nitrate, phosphate, total solids, volatile solids, total suspended solids and volatile suspended solids. The results of the analysis indicated that there are significant differences in the values of leachate and permeate parameters. The permeate parameters had values very much lower than those of leachate. It reveals that the clay-waste polyethylene-clay composite liner system reduced the concentration of these parameters when the leachate passed through the liner. The biofilm formed in waste polyethylene within the liner may have degraded most of organic materials found in the leachate when it passed through the liner. Therefore, the clay-waste polyethylene-clay composite liner system can be applied for full scale landfill bioreactors, particularly for Asian developing countries, due to better performance and more environmentally friendly characteristics.     

Mining taxation issues for the future

During the 1970s and 1980s the main concern of mining policies was to attract investment whilst at the same time balancing the interests of governments and companies. By the turn of the century a new spectrum of challenges faces governments and companies in the mining sector. The need for fiscal regimes to adapt to price cyclicity is to some extent superseded by the requirement that they adapt to a long-term decline of metal prices. The growing importance of environmental and community affairs in the mining sector will force governments to design coherent and comprehensive tax regulations to complement the wide range of initiatives being taken in these fields. Finally, the age-old problem of tax collection continues to raise its head in transition and developing economies.