From the first millennium B.C. through the 9th-century A.D. Classic Maya collapse, nonurban populations grew exponentially, doubling every 408 years, in the twin-lake (Yaxha-Sacnab) basin that contained the Classic urban center of Yaxha. Pollen data show that forests were essentially cleared by Early Classic time. Sharply accelerated slopewash and colluviation, amplified in the Yaxha subbasin by urban construction, transferred nutrients plus calcareous, silty clay to both lakes. Except for the urban silt, colluvium appearing as lake sediments has a mean total phosphorus concentration close to that of basin soils. From this fact, from abundance and distribution of soil phosphorus, and from continuing post-Maya influxes (80 to 86 milligrams of phosphorus per square meter each year), which have no other apparent source, we conclude that riparian soils are anthrosols and that the mechanism of long-term phosphorus loading in lakes is mass transport of soil. Per capita deliveries of phosphorus match physiological outputs, approximately 0.5 kilogram of phosphorus per capita per year. Smaller apparent deliveries reflect the nonphosphatic composition of urban silt; larger societal outputs, expressing excess phosphorus from deforestation and from food waste and mortuary disposal, are probable but cannot be evaluated from our data. Eutrophication is not demonstrable and was probably impeded, even in less-impacted lakes, by suspended Maya silt. Environmental strain, the product of accelerating agroengineering demand and sequestering of nutrients in colluvium, developed too slowly to act as a servomechanism, damping population growth, at least until Late Classic time.
Community-based ecosystem monitoring activities in Canada are increasing in response to a number of factors including: (i) the needs of decision-makers for timely information on local environmental changes; (ii) limited use of government monitoring data and information by decision makers: (iii) government cuts to monitoring programs; (iv) the increasingly recognized need to include stakeholders in planning and management processes; and (v) the desire of citizens to contribute to environmental protection. To date there has been no network coordination of community based monitoring in Canada. This paper reports on the establishment of the Canadian Community Monitoring Network by Environment Canada's Ecological Monitoring and Assessment Network Coordinating Office and the Canadian Nature Federation. Information on research prepared in support of network establishment is presented along with a discussion of the potential of the network.
BackgroundPublic environmental concerns and issues are increasingly place-based and related to ecological sustainability. As a result, measures of scientific success for ecologists no longer simply involve developing new information and making it available, but should also incorporate the production and delivery of information that improves and informs decisions and policies. The word "delivery" is deliberately chosen to indicate that an ongoing dialogue with those who require or use ecological information in making choices or developing policies must be involved in order to ensure that tailored information fulfills users' needs. This additional focus Ecological information that adequately informs society's decisions often differs in several ways from that which science routinely provides. This workshop examined changes that may be required if some of society's pressing goals (eg sustained provision of ecosystem services, establishment of policy that adequately reflects interacting economic, social, and environmental factors, and an engaged public making increasingly informed choices) are to be achieved. Using a common framework, representatives of the Long Term Ecological Research networks in Canada, the US, and Mexico described their concerns and initiatives related to the delivery and effectiveness of the data and information they generate. Workshop participants reached consensus on a number of recommendations: (1) that it is the responsibility of ecologists to effectively inform societal choices, policies, and decisions; (2) that improved outcomes need to be an additional performance measure at a science program level; and (3) that a variety of recommendations need to be acted upon to enhance the effectiveness of ecological science. A full symposium through the Ecological Society of America is suggested. Front Ecol Environ 2007; 5(4): W8-W11
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