30 years of large river restoration: How long do restored floodplain channels remain suitable for targeted rheophilic fishes in the lower river Rhine?

The ecological efficacy of river restoration projects may change over time, resulting in the loss of their ecological function for targeted species. The goal of this study was to evaluate the rheophilic nursery function of restored floodplain channels over time, by analysing 30 years of monitoring data from 12 restoration projects in the lower river Rhine. We hypothesised that the nursery function would change over time, caused by the combined effects of decreasing flow conditions and succession processes affecting habitat heterogeneity. We found that nursery area suitability for rheophilic fish was almost 4 times higher in two-sided connected channels than in one-sided connected channels, although the response trends of rheophilic fish were similar for both water body types. These response curves showed clear optima with channel age, for rheophilic fish abundance at 13 to 14 years post-restoration, indicating optimal nursery conditions. On the other hand, rheophilic species richness showed a steadily decreasing trend with channel age, suggesting aging channels became less suitable as nursery areas for most rheophilic fish species. The presence of permanent flow was found to be the main driving factor in explaining both rheophilic fish community trends and habitat succession in individual restored channels. We did not observe an effect of habitat heterogeneity on nursery function for rheophilic fish. To create and maintain optimal nursery conditions in restored floodplain channels of strongly anthropogenically influenced rivers such as the river Rhine, we propose a management strategy involving cyclic rejuvenation through human intervention, focusing on restoring permanent flow, with a frequency of on average every 15 years, depending on the rate of aggradation and targeted rheophilic species. We also propose a thorough investigation of the relationship between habitat heterogeneity and nursery success in floodplain channels, as a next step in the identification of suitable nursery areas for rheophilic fishes.

Longitudinal training dams mitigate effects of shipping on environmental conditions and fish density in the littoral zones of the river Rhine.

The stability of habitat conditions in littoral zones of navigated rivers is strongly affected by shipping induced waves and water displacements. In particular, the increase of variability in flow conditions diminishes the suitability of these habitats for juvenile fishes. Recently, a novel ecosystem based river management strategy has resulted in the replacement of traditional river training structures (i.e., groynes) by longitudinal training dams (LTDs), and the creation of shore channels in the river Waal, the main, free-flowing and intensively navigated distributary of the river Rhine in the Netherlands. It was hypothesized that these innovative LTDs mitigated the effects of shipping on fishes by maintaining the natural variability of habitat conditions in the littoral zones during ship passages whereby shore channels served as refugia for juvenile fishes. Measurements of abiotic conditions showed a significantly lower water level fluctuation and significantly higher flow stability in shore channels compared to groyne fields. Flow velocity did not differ, nor did the variation in flow velocity fluctuation during ship passage between these habitats. Densities of fish were found to be significantly higher in the littoral zones of shore channels compared to nearby groyne fields. Moreover, electrofishing along the inner side of the newly constructed LTD showed a significant linear relationship between fish density and distance from highly dynamic in- and outflow sections and to lowered inflow sections in the LTD. Results of our field sampling clearly indicate successful ecological rehabilitation of littoral zones that coincides with a facilitation of navigation in the main river channel and increased flood safety.

Alcoholism and the general practitioner.

Fifty-three urban general practitioners were questioned about alcoholism. They mostly had reasonably good, if sometimes muddled knowledge of the condition, when to suspect it, and how to confirm its presence. Social harms were seen as predominant over somatic ones. The majority had had postgraduate instruction supplemented by reading. Most were prepared to treat alcoholics, and revealed tolerant and sympathetic attitudes towards them and their families. The survey negates the general impression of unwillingness by general practitioners to engage with alcoholism.

Effect of the 1983 Mental Health Act on the management of psychiatric patients.

Two principal objectives of the 1983 Mental Health Act were to decrease the use of emergency orders and to give patients on observation orders the right of appeal. Statistics were collected from the 13 hospitals that admit acute psychiatric patients in the Greater Manchester area, and the figures for 1980-1 were compared with those for 1984-5. Changes in use of the different sections were examined in university units, large psychiatric hospitals, and district general hospital units. The use of emergency orders decreased and the use of treatment orders increased; the use of observation orders remained unchanged. Many more patients exercised their right of appeal in 1984-5, but the number discharged by tribunals remained small. The nurses' holding power was used infrequently. The different types of hospital are now more concordant in their use of these orders than before the 1983 act.

The comparability of suicide rates.

Programmes of suicide prevention require for their planning accurate epidemiological surveys. Doubt has been cast on the accuracy of many existing surveys because of the realization that suicide is under-reported and because of the lack of consistency in the procedure for suicide ascertainment. Two studies are described in this paper which attempt to examine the problem. The first is part of an international study supported by the World Health Organization. In it, Denmark and England are compared, and it is shown that there are striking differences in suicide ascertainment procedure between the two countries. Next, on a blind basis, coroners and their opposite numbers in Denmark examine a sample of each other's case records. It is found that the Danes consistently report more suicides than do the English coroners on the same case material; thus considerable doubt is cast on the supposed difference in suicide rates between the two countries. In the second study, deaths by poisoning are examined for certain coroners' districts in England and Wales. It is shown that there is considerable variation from one district to another in the relative proportions of these deaths which achieve an accident, an open or a suicide verdict. This suggests that in England and Wales coroners may not be consistent in their suicide ascertainment criteria. Hypotheses attempting to account for differences in suicide rate based on such epidemiological surveys should be viewed with great caution.

The Manchester detoxification service. Description and evaluation.

The service of Manchester's hospital-based purpose-built alcohol detoxification centre is described, together with demographic data, drinking history, findings on admission, disposal arrangements, and outcome of 235 police referrals. Police referrals under-used the centre, which now accepts from magistrates' courts, the local alcoholism council, accident and emergency departments, and general practice. Police referrals, mostly homeless and without family support, contained many episodic drinkers; this explains the low incidence of severe withdrawal symptoms. Prophylactic treatment was not routine. Very high blood alcohol levels were recorded from some conscious patients. There was little serious medical morbidity. Many discharged themselves within 24 hours. Few accepted the recommended treatment, medical or social; prolonged abstinence was achieved by only 1% but substantially more had short abstinent periods and some social betterment, especially if offered follow-up help. Visits to general practitioners' surgeries fell during the follow-up period, as did admissions to general units for withdrawal symptoms, though not from all causes. Almost half had readmissions to the centre. Referrals from other sources were more likely to stay for assessment and accept help. More referrals from medical sources had severe withdrawal symptoms. Detoxification centres need not be in hospitals but must have close and rapid links with specialist medical services. They must be integrated into the total provision of alcoholism services and assessed in relation to them.