Taxon richness

Beaver ponds downstream from an abandoned copper-nickel ore roast yard near Sudbury, Ontario, were devoid of fish and had reduced macroinvertebrate taxon richness and diversity when compared to upstream ponds. Nickel water concentrations, in pg Ni/L, were 57 in upstream ponds,... 

Seasonal patterns in taxon richness were also different in the two streams. For example, during snowmelt and in summer, Diamesinae and Orthocladiinae richness was higher in Konigsbach, whereas in autumn and winter the glacier-fed stream had more taxa within the two subfamilies. In both streams, taxon richness was highest in... 

Williams PH, Gaston KJ, Humphries CJ. 1997. Mapping biodiversity value worldwide combining higher-taxon richness from different groups. Proc R Soc Lond B Biol Sci 264 141-148. 

Most new indicator systems are based on metrics, i.e. attributes of the biotic assemblages, which reflect community composition and abundance, taxon richness, the proportion of sensitive and tolerant taxa or functional attributes (Hering et al., 2006). They are designed to assess overall ecological stress, e.g. deviation from reference conditions, or to assess single stressors, e.g. eutrophication (Kelly et al, 1995), organic... 

Figure 7.4.9 Conceptual diagram illustrating a comparison of expected and observed responses of macroinvertebrates (expressed as taxon richness) in acidified and reference lakes in southern Sweden to a reduction in sulphur deposition. (Reproduced by permission of Wiley-Blackwell)...

Beaver ponds downstream from an abandoned copper-nickel ore roast yard near Sudbury, Ontario, were devoid of fish and had reduced macroinvertebrate taxon richness and diversity when compared to upstream ponds. Nickel water concentrations, in p,g Ni/L, were 57.0 in upstream ponds, 82.0 in downstream ponds, and 1800.0 at the station directly on the roast pit. Beavers (Castor canadensis) near nickel smelters had elevated luckel concentrations in livers and kidneys when compared to conspecifics from a reference site accumulations were attributed to food chain contamination. 

Sorangium cellulosum is an ubiquitous soil bacterium that belongs to the order Myxococcales. It has the ability to glide over solid surfaces, to live in a biofilm and form fruiting bodies. Members of this taxon are a particularly rich source of metabolites with remarkable biological activities [177]. From one strain, another example of N-acyl-4-methoxy-3-pyrrolin-2-ones has been isolated. Eliamid (110) has been claimed to have cytostatic, nematocidal and fungicidal activities [178]. 

The taxon S. arborescens subsp. paulii was collected in Andalusia and found to be rich in diterpenoids [90]. Some known ent-labdanes were found 6-deoxyandalusol (100), 6-deoxyandalusal (101), 6-... 

The families Papaveraceae and Fumariaceae are well known as taxonomic groups, and both are very rich in specific alkaloids. Some of them are important in medicine and some others can be considered as promising in this sense (1,2). Therefore it is not surprising that in the past and especially at present these alkaloids belong to those that have been most intensively studied 3-9). A vast quantity of material has been accumulated, which represents a rich potential source of medicinal compounds of plant origin and a significant taxon in plant systematics. In this connection, attempts are made by both botanists and chemists to find a correlation between chemical properties and botanical features. 

Both brachiopods and crinoids occur in the Tertiary deposits exposed in the Scotland District, northeast Barbados. Brachiopods and crinoids occur in the Lower Miocene Bissex Hill nappe, part of the prism cover that rests on the Paleogene basal complex of the Lesser Antillean accretionary prism (Speed, 1994). The brachiopods are micromorphic shells of Argyrotheca and Terebratulina (Fig. 28.2F-I), which occur in Globigerina-rich marlstones and sandstones. These minute shells are homeomorphs and can be confused easily. There is a wealth of crinoid material from Bissex Hill, although limited to only one taxon, the isocrinid Neocrinus decorus (Donovan and Veltkamp, 2001). 

S. tomentosa Benth. (S. rhexioides Klotzsch ex Rich. Schomb., name only) is a huge liane, up to 10 cm in diameter, with very large fruits, also as much as 10 cm in diameter, found in various types of forest in the Guianas and across the northern part of Amazonian Brazil (108, 217, 221), where it is included in curares. Specimens from Venezuela formerly identified as belonging to this species have been transferred to the new taxon S. davidsei Krukoff et Barneby (219). 

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