PLANT AND ANIMAL SCIENCES
BY PETER D. MOORE
Department of Biology
Considerable debate surrounds the decline and collapse of the Central American Maya culture. The analysis of carbon and nitrogen isotopes in bones from Maya burials has now permitted some reconstruction of diet. The importance of maize has been confirmed, though it does seem to have become a less important dietary element at the time of the Maya collapse.
C.D. White, H.P. Schwarcz, “Ancient Maya diet: as inferred from isotopic and elemental analysis of human bone,” Journal of Archaeological Science, 16,451-74, September 1989,’ (University of Toronto, Ontario, Canada; McMaster University, Hamilton, Ontario, Canada)
Large predatory birds often require extensive hunting territories, for survival. Assessment of their density may provide a simple indication of the minimum area needed for a nature reserve. Studies in the rain forests of French Guiana show that a 10,000-hectare sample plot only rarely includes the full set of forest raptors. Viable populations would require reserves of at least one million to 10 million hectares.
J.M. Thiollay, “Area requirements for the conservation of rain forest raptors and game birds in French Guiana,” Conservation Biology, 3, 128-37, June 1989. (Laboratoire d’Ecologie, Paris, France)
" The influence of climatic warning on flowering and leaf production in trees could have considerable economic significance in both forestry and horticulture. The duration of the chill period affects the speed of response to spring warming, so prediction is complex. British studies, however, suggest that the effects of warming (increase of 30C) will be minimal in lowland sites, but would have a marked influence on budburst in the uplands.
M.B. Murray, M.G.R. Cannell, R.I. Smith, “Date of budburst of fifteen tree species in Britain following climatic warming,”Journal of Applied Ecology, 26,693-700, August 1989. (Institute of Terrestrial Ecology, Penicuik, Scotland)
" One can argue that-an isolated plant is more likely to escape the attentions of insect herbivores than one found in a patch of the same species. On the other hand, a high density of herbivores in a patch of plants is more likely to prove attractive to predators, which may control population growth among the plant feeders. The role of predatory, insectivorous animals could thus be important in determining the selection of dispersal strategies among plants.
C.D. Thomas, “Predator-herbivore interactions and the escape of isolated plants from phytophagous insects,” Oikos, 55,291-8, July 1989. (University of Canterbury, New Zealand)
" Pollen cryobanks, in which the pollen of economically important plants can be kept viable for long periods, have already been established in temperate areas, such as Japan, Hawaii, and California. A storage laboratory has now been established in India for the preservation of pollen of tropical fruits and vegetables. Good viability has now been recorded over five-year storage periods.
S. Ganeshan, M.P. Alexander, "Pollen preservation in tropical fruits and vegetables for establishing pollen cryobanks in India,” Diversity, 5, 18-19, September 1989. (Institute of Horticultural Research, Bangalore, India)
" Evidence for floral extinctions at the Cretaceous/Tertiary boundary has been somewhat obscured by taxonomic uncertainties when based on pollen and spore assemblages. Analyses of whole plant parts, such as leaves, have now demonstrated that the boundary was a time of major plant extinction.
K.R. Johnson, D.J. Nichols, M. Attrep, Jr., C.J. Orth, “High-resolution leaf-fossil record spanning the Cretaceous/Tertiary boundary,” Nature, 340, 708-11, 31 August 1989. (Yale ( University, New Haven, Conn.; U.S. Geological Survey, Denver, Cob.; Los Alamos National Laboratory, N.Mex.)
" The fossil record of animals and plants in sediments dating from the end of the last ice age, about 10,720 solar years ago (about 10,000 radiocarbon years), indicates a rapid warming of climate at that time. Just how rapid has been demonstrated by oxygen isotope analyses of ice cores from the Greenland ice cap. During the course of only 50 years, the temperature rose by TC.
W. Dansgaard, J.W.C. White, S.J. Johnsen, “The abrupt termination of the Younger Dryas climate event,” Nature, 339, 532-4, 15 June 1989. (University of Copenhagen, Denmark; University of Colorado, Boulder; University of Iceland, Reykjavik)
" Even in structurally simple ecosystems, food-web interactions can be complex. In stands of reed (Phragmites australis), for example, gall midges are most successful in invading thin, nutrient-starved stalks. But the fatter, more vigorous stems may be attacked by stem-boring moth larvae, in which case thin side shoots develop and the gall midges then move in.
T. Tschamtke, “Attack by a stem-boring moth increases susceptibility of Phragmites australis to gall-making by a midge: mechanisms and effects on midge population dynamics,” Oikos, 55, 93-100 00, May 1989. Universität Karlsruhe, F.R.G.)