A further biodiversity index is proposed, based on taxonomic (or phylogenetic) relatedness of species, namely the Œvariation in taxonomic distinctness¹ (VarTD, Λ+) between every pair of species recorded in a study. It complements the previously defined Œaverage taxonomic distinctness¹ (AvTD, Δ+), which is the mean path length through the taxonomic tree connecting every pair of species in the list. VarTD is simply the variance of these pairwise path lengths and reflects the unevenness of the taxonomic tree. For example, a species list in which there are several different orders represented only by a single species, but also some genera which are very species-rich, would give a high Λ+ by comparison with a list (of equivalent Δ+) in which all species tended to be from different families but the same order. VarTD is shown to have the same desirable sampling properties as AvTD, primarily a lack of dependence of its mean value on the sample size (except for unrealistically small samples). Such unbiasedness is of crucial importance in making valid biodiversity comparisons between studies at different locations or times, with differing or uncontrolled degrees of sampling effort. This feature is emphatically not shared by indices related to species richness and also not by properties of the phylogeny adapted from proposals in other, conservation contexts, such as Œaverage phylogenetic diversity¹ (AvPD, Φ+). As with AvTD, the VarTD statistic for any local study can be tested for Œdeparture from expectation¹, based on a master taxonomy for that region, by constructing a simulation distribution from random subsets of the master list. The idea can be extended to summarising the joint distribution of AvTD and VarTD, so that values from real data sets are compared with a fitted simulation Œenvelope¹ in a 2 d (Δ+, Λ+) plot. The methodology is applied to 14 species lists of free-living marine nematodes, and related to a master list for UK waters. The combination of AvTD and VarTD picks out, in different ways, some degraded locations (low Δ+, low to normal Λ+) and the pristine island fauna of the Scillies (normal + , high Λ+). The 2 indices are also demonstrated to be measuring effectively independent features of the taxonomic tree, at least for this faunal group (although it is shown theoretically that this will not always be the case). The combination of Δ+ and Λ+ is therefore seen to provide a statistically robust summary of taxonomic (or phylogenetic) relatedness patterns within an assemblage, which has the potential to be applied to a wide range of historical data in the form of simple species lists.

/pdf/a-further-biodiversity-index-applicable-to-species-lists-3uqa49ai08.pdf

A further biodiversity index applicable to species lists: variation in taxonomic distinctness

Many wildlife species may be exposed to biologically active concentrations of endocrine-disrupting chemicals There is strong evidence obtained from laboratory studies showing the potential of seve

https://push-zb.helmholtz-muenchen.de/deliver.php?id=2568

Health Effects of Endocrine-Disrupting Chemicals on Wildlife, with Special Reference to the European Situation

A field experiment was conducted in Delaware (USA) to evaluate three crude oil bioremediation techniques. Four treatments were studied: no oil control, oil alone, oil + nutrients, and oil + nutrients + an indigenous inoculum. The microbial populations were monitored by standard MPN techniques, PLFA profile analysis, and 16S rDNA DGGE analysis for species definition. Viable MPN estimates showed high but steadily declining microbial numbers and no significant differences among treatments during the 14-weeks. Regarding the PLFA results, the communities shifted over the 14-week period from being composed primarily of eukaryotes to Gram-negative bacteria. The Gram-negative communities shifted from the exponential to the stationary phase of growth after week 0. All Gram-negative communities showed evidence of environmental stress. The 16S rDNA DGGE profile of all plots revealed eight prominent bands at time zero. The untreated control plots revealed a simple, dynamic dominant population structure throughout the experiment. The original banding pattern disappeared rapidly in all oiled plots, indicating that the dominant species diversity changed and increased substantially over 14 weeks. The nature of this change was altered by nutrient-addition and the addition of the indigenous inoculum.

/pdf/microbial-population-changes-during-bioremediation-of-an-46czbde8f8.pdf

Microbial Population Changes During Bioremediation of an Experimental Oil Spill

A review of organotin regulatory strategies, pending actions, related costs and benefits.

This review examines the various strategies and methods used to produce benthic habitat maps using acoustic remote sensing techniques, coupled with in situ sampling. The applications of three acoustic survey techniques are examined in detail: single-beam acoustic ground discrimination systems, sidescan sonar systems, and multi-beam echo sounders. Over the past decade we have witnessed the nascence of the field of benthic habitat mapping and, on the evidence of the literature reviewed in this paper, have seen a rapid evolution in the level of sophistication in our ability to image and thus map seafloor habitats. As acoustic survey tools have become ever more complex, new methods have been tested to segment, classify and combine these data with biological ground truth sample data. Although the specific methods used to derive habitat maps vary considerably, the review indicates that studies can generally be categorized into one of three over-arching strategies; 1) Abiotic surrogate mapping; 2) Assemble first, predict later (unsupervised classification); 3) Predict first, assemble later (supervised classification). Whilst there is still no widely accepted agreement on the best way to produce benthic habitat maps, all three strategies provide valuable map resources to support management objectives. Whilst there is still considerable work to be done before we can answer many of the outstanding technological, methodological, ecological and theoretical questions that have been raised here, the review concludes that the advent of spatial ecological studies founded on high-resolution environmental data sets will undoubtedly help us to examine patterns in community and species distributions. This is a vital first step in unraveling ecological complexities and thus providing improved spatial information for management of marine systems.

Benthic habitat mapping: A review of progress towards improved understanding of the spatial ecology of the seafloor using acoustic techniques

In the United Kingdom, the use of TBT-based anti-fouling paints on small vessels was banned in 1987, and a biological study of the Crouch Estuary, a yachting centre on the south-eastern coast of the UK, was conducted in order to determine the ecological improvements resulting from this legislation. We present the changes in the macro-infaunal communities along the estuary in relation to declining TBT concentrations between 1987 and 2005. Although the major changes in response to the ban were observed within the first 3 years (primarily an increase in the number of crustacean taxa and a shift in community structure), with changes still apparent between three and 5 years, the temporal duration of this study allowed the rapidity of the response to be truly determined.

Macrofaunal recovery following TBT ban. Long-term recovery of subtidal macrofaunal communities in relation to declining levels of TBT contamination.

Performance of selected indicators in evaluating the consequences of dredged material relocation and marine aggregate extraction

Structure, distribution, and characterizing species of North Sea macro-zoobenthos communities in 2000

The eastern English Channel marine habitat map

The estuary of the River Crouch, south-east England, as sampled annually by beam trawl between 1987 and 1989, and again in 1992. The aim of an initial transect survey was to describe and quantify the subtidal epifauna at a time of high ambient tributyltin (TBT) concentrations, arising from the use of tin-based anti-fouling paints on the hulls of moored pleasure craft. Subsequent surveys at representative stations sought to examine the progress of any changes with time in animal populations in relation to a decline in concentrations of TBT in the environment, following a ban on the use of tin-based paints for smaller vessels in July 1987.

H.L. Rees

Papers

Macrofaunal recovery following TBT ban. Long-term recovery of subtidal macrofaunal communities in relation to declining levels of TBT contamination.

Performance of selected indicators in evaluating the consequences of dredged material relocation and marine aggregate extraction

Structure, distribution, and characterizing species of North Sea macro-zoobenthos communities in 2000

The eastern English Channel marine habitat map

Surveys of the epibenthos of the Crouch Estuary (UK) in relation to TBT contamination