摘要:

New Zealand landscapes were extensively modified after European settlement in the late 1800s. Large areas of native forest were converted to pasture and few large areas of unmodified forest remain. Trout (Salmo truttaandOncorhynchus mykiss) were introduced into the rivers at the same time, and these two changes are thought to have affected native fish communities. Kahurangi National Park is a large area of unmodified native forest with few introduced trout in smaller rivers draining to the west. A survey of these streams was made to determine whether their communities differed from those in other areas of New Zealand. No non‐diadromous native fish were found, suggesting a biogeographic separation from adjacent eastern and southern areas since the Pliocene or early Pleistocene. Contrary to popular expectation, fish diversity and abundance was often lower than at equivalent elevations in other areas of New Zealand. Lowland fish communities comprised a small stream community dominated by inanga (Galaxias maculatus), a small stream community containing a mixed galaxiid population but dominated by banded kokopu (Galaxias fasciatus), and two large stream communities containing the fastwater species bluegilled bully (Gobiomorphus hubbsi), and dominated by either redfinned bully (Gobiomorphus huttoni) or bluegilled bully. Large streams usually contained no in‐stream cover with margins of exposed streambed, whereas small streams contained plentiful cover with margins of native forest, native grasses, or swamp. Upland fish communities were dominated by koaro (Galaxias brevipinnis) and/or longfinned eels (Anguilla dieffenbachii). Large‐stream fish communities in Kahurangi National Park were similar to the fastwater communities in medium‐large rivers in other areas of New Zealand. However, in the smaller streams of Kahurangi National Park, galaxiid communities were encountered more frequently than in similar sized streams in other parts of New Zealand.

ISSN:0028-8330    

DOI:10.1080/00288330.1998.9516827

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Management of faecal contamination of water would be improved if sources could be accurately identified through water analysis. Human faeces are generally perceived as constituting a greater human health risk than animal faeces, but reliable epidemiological evidence is lacking. United States waterborne disease data suggest that human‐specific enteric viruses account for over half the documented outbreaks. However, in New Zealand, where there is a high grazing animal:human ratio (increasing the relative importance of water‐transmissible zoonoses), it seems prudent to assume that human and animal faecal pollution both constitute a risk to human health. Irrespective of the relative risks, the ability to identify sources would assist in overall management of microbial water quality. Faecal streptococci do not appear to provide reliable faecal source identification. Human and animal sources, respectively, maybe distinguishable by two tests onBifidobacteriumspp.—growth at 45°C in trypticase phytone yeast broth and sorbitol fermentation. Different species ofBacteroidestend to be present in humans and animals, but poor survival in water is a problem. Phages of theBacteroides fragilisstrain HSP40 appear to be human specific, but low counts in effluent in some countries, including New Zealand, may limit their usefulness. Different F‐RNA phage subgroups appear to be associated with human and animal faecal sources. The actinomyceteRhodococcus coprophilushas potential as a grazing animal indicator but it is persistent, and existing culturing techniques are time consuming. The development of DNA‐based techniques, such as polymerase chain reaction (PCR), may assist in the assay of some microbial faecal source indicators. Various faecal sterol isomers offer the possibility of distinguishing between human and animal sources, and even between different animals. Washing powder constituents such as fluorescent whitening agents, sodium tripolyphosphate and linear alkyl benzenes, offer useful human source identifiers. It is unlikely that any single determinand will be useful in all situations, but statistical analysis of appropriate “baskets” of microbial and chemical determinands offers the possibility of identifying and apportioning human and animal faecal inputs to natural waters.

ISSN:0028-8330    

DOI:10.1080/00288330.1998.9516828

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:0028-8330    

DOI:10.1080/00288330.1998.9516829

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor