Showing papers by "Amazon.com published in 1994"

Natural forest disturbance and change in the Brazilian Amazon

Abstract: Landsat Thematic Mapper images covering the entire 3.9 million km2 of forested Brazilian Amazon reveal natural change and disturbance occurring on a scale of decades to centuries. These include: 92,000 km2 of bamboo forests undergoing synchronous mortality and regrowth; 1500 km2 of recently active dune fields; 900 km2 of recent downburst blowdowns; > 500 km of recent forest fire scars; and an unknown area of forest mortality from flooding of high ground and alluvial forests. Fire subclimax fern savannas created by Yanoama Indians cover an additional 600 km2. Natural and indigenous disturbances and synchronized phenologies are therefore responsible for a dynamic spectral bahavior in large portions of the Amazon Basin. Disturbances and disturbance indicators not easily detected include blowdown sites > 30 yrs old, blowdowns < 30 hectares in size, liana forests and babassu palm forests.

FOOD CONCENTRATION AND TEMPERATURE EFFECTS ON LIFE CYCLE CHARACTERISTICS OF TROPICAL CLADOCERA (Daphnia gessneri Herbst, Diaphanosoma sarsi Richard, Moina reticulata (Daday)): I. DEVELOPMENT TIME

Abstract: The effects of food concentration and temperature on embryonic and postem-bryonic duration of three tropical species, Daphnia gessneri(1.5mm), Diaphanosoma sarsi(1.2mm) and Moina reticulata(0.8mm), were investigated as part of life cycle studies which included growth, body size and reproduction. These are the very first experimental studies undertaken on these species. The long-term growth experiments were performed under controlled laboratory conditions at all combinations of temperature (22"C, 27"C and 32"C) and constant food concentration (0.03, 0.05, 0.10, 0.25, 0.50 and 1.00 mgC/L) of the unicellular green alga Scenedesmus acutus.Animals were examined twice daily throughout their life cycle from the neonate to third adult instar. In all three species, temperature exerted the most powerful influence on embryonic duration but there was also a smaller food effect. In D. gessneri,postembry-onic durations remained more or less the same at food levels 0.25 mgC/L but were influenced by temperature. At food concentrations of 0.1 mgC/L or lower, postembryonic durations became increasingly prolonged, particularly at high temperatures. This threshold concentration is affected by temperature: in D. gessneri,it was 0.1 mgC/L at 22oC and 27oC but higher at 32oC (between 0.25 and 0.50 mgC/L). At the same temperature of 27oC, the food threshold level varied between species: it was higher (0.25 mgC/L) for D. sarsiand lower (0.05 mgC/L) for M. reticulatacompared with D. gessneri(0.1 mgC/L). In both embryonic and postembryonic durations there is a body size effect as the absolute durations were longest in the largest species and shortest in the smallest species In all three species, prolongation of postembryonic duration at combinations of high temperature and lowered food levels was accompanied by increased number of juvenile instars.

The canadian feasibility study of the three gorges dam proposed for china's yangzi river: a grave embarrassment to the impact assessment profession

Abstract: I.) THE THREE GORGES PROJECT II.) THE CANADIAN FEASIBILITY STUDY A.) THE ROLES OF CIDA AND THE WORLD BANK B.) INTERNATIONAL CONTROVERSY OVER THREE GORGES C.) THE PURPOSE OF THE FEASIBILITY STUDY III.) THE CANADIAN ASSESSMENT OF RESETTLEMENT IMPACTS A.) EXPECTED FLOOD LEVELS B.) GOVERNMENTS CHANGE THEIR MINDS C.) DRAFT PLANS D.) BUDGET E.) CHINA'S RECORD OF RESETTLEMENT F.) LAND AVAILABILITY AND QUALITY G.) MINORITY AREAS H.) NONPERSONS I.) RURAL TO URBAN MIGRATION POLICY J.) THE ZERO SUM DILEMMA K.) CONSULTATION OF THE LOCAL POPULATION L.) IRREVERSIBILITY IV.) THE CONCLUSIONS OF THE CANADIAN STUDY V.) LESSONS FOR THE IMPACT ASSESSMENT PROFESSION A.) THE QUESTION OF EXPERT PROSTITUTION B.) AN ADVOCACY STRUCTURE FOR DECISION-MAKING C.) AN END TO SECRECY VI.) LIST OF ABBREVIATIONS VII.) ACKNOWLEDGMENTS VIII.) LITERATURE CITED