SUMMARYSample sub-populations, each of six plants, were chosen for high, mid and low tolerance of copper from each of two naturally-occurring copper tolerant populations and from tolerant individuals selected from a cultivar of Agrostis capillaris L. The naturally-occurring ecotypes came from a closed sward community at Drws y Coed, and from an open community at Parys Mountain, both copper mines in North Wales. Clonal replicates of all plants were introduced into swards of perennial ryegrass cvs. S23 or S24, growing on normal soil at the University of Liverpool Botanic Gardens. S23 plots were cut eight times between June 1977 and July 1978, whilst S24 plots were cut 3 times during the same period. Half the experimental plots received N, P, K, fertilizer; the rest received none.Plants selected from the cultivar (selected) produced most dry matter, and with infrequent defoliation flowered freely in competition with ryegrass. Those taken from Parys Mountain mine spoil produced least dry matter and no inflorescences. Drws y Coed plants were intermediate in dry matter and inflorescence production. These results may reflect differences in population density in the habitats from which the populations were sampled.Sub-populations chosen for high, mid or low copper tolerance within the selected and Drws y Coed populations did not differ signiflcantly in dry matter yield. By contrast under certain circumstances Parys Mountain plants with low tolerance outyielded other more tolerant plants.These results are considered with respect to growth strategies adopted by plants growing on and off copper mine sites.

The effect on vegetation communities of release from grazing by camels and goats has been investigated in the Baynunah region of Abu Dhabi emirate, in The United Arab Emirates, by the study of an exclosure established 11 years previously. Also the effect of sprinkle irrigation (in the absence of grazing) on the rangeland vegetation was investigated. Perennial species richness was significantly lower outside the exclosure compared with inside on both sand and gravel substrata. Annual species richness however was not significantly different. Perrenial percentage covers were lower outside the exclosure compared with inside, especially on sand substrata. The perennial grass Stipagrostis pfumosa (L) showed the greatest difference in percentage cover in this respect. The species richness of annuals and perennials was not significantly different between irrigated and non-irrigated areas within the exclosure. The perennial percentage cover was much greater on sprinkle irrigated sand and gravel substrata. The perennial which benefited the most was Zygophyllum hamiense, Scweinf. Annual percentage cover was lower in irrigated quadrats. Suggestions are made about the effect of intensive grazing on the vegetation communities at Baynunah and on the effectiveness of irrigation as a tool for increasing the quality of the rangeland for livestock and wildlife.

Summary The rooting response of seven populations of Agrostis tenuis Sibth. to a range of copper concentrations in calcium nitrate solution is described. Variation in both index of tolerance and sensitivity of rooting to increased copper levels were found and shown to be phenotypically independent characters. It is suggested that rooting sensitivity to a range of copper concentrations provides a further measure of copper tolerance which is independent of the methods previously employed for assessing tolerance.

No abstract

The peregrine falcon (Falco peregrinus) has been affected by persecution, pollution, trade and habitat degradation, but it is considered a flagship conservation success story because of successful reintroductions. However, in the UK there were never formal reintroduction programmes for peregrine falcons, and it appears that UK populationsand specifically the Sussex peregrines of the English south coastrecently recovered from a population crash unassisted. To study this, we obtained samples from contemporary populations in southern England, Ireland, continental Europe, domestic-bred peregrine falcons, and from England prepopulation crash. Using microsatellite and mtDNA control region data, the genetic diversity and structure, signatures of genetic bottlenecks, and potential origin of the Sussex peregrines was investigated. We found low levels of genetic diversity across all peregrine falcon populations, low but significant genetic differentiation among all populations, and a few private alleles, indicating some level of genetic structure in European peregrines. Although we could not pinpoint the origin of the Sussex peregrines, the data suggests that it is not likely to have originated from escaped domestic birds or from adjacent European populations. The results obtained here parallel other studies on peregrines elsewhere showing low genetic diversity but genetic structure. We conclude that not enough time elapsed for genetic erosion to occur due to the population bottleneck, and that at least for the Sussex peregrines there is no need for genetic conservation by wild-take and subsequent captive breeding programmes as long as current protection measures remain in place.