Guiding ecological principles for marine spatial planning

The declining health of marine ecosystems around the world is evidence that current piecemeal governance is inadequate to successfully support healthy coastal and ocean ecosystems and sustain human uses of the ocean. One proposed solution to this problem is ecosystem-based marine spatial planning (MSP), which is a process that informs the spatial distribution of activities in the ocean so that existing and emerging uses can be maintained, use conflicts reduced, and ecosystem health and services protected and sustained for future generations. Because a key goal of ecosystem-based MSP is to maintain the delivery of ecosystem services that humans want and need, it must be based on ecological principles that articulate the scientifically recognized attributes of healthy, functioning ecosystems. These principles should be incorporated into a decision-making framework with clearly defined targets for these ecological attributes. This paper identifies ecological principles for MSP based on a synthesis of previously suggested and/or operationalized principles, along with recommendations generated by a group of twenty ecologists and marine scientists with diverse backgrounds and perspectives on MSP. The proposed four main ecological principles to guide MSP—maintaining or restoring: native species diversity, habitat diversity and heterogeneity, key species, and connectivity—and two additional guidelines, the need to account for context and uncertainty, must be explicitly taken into account in the planning process. When applied in concert with social, economic, and governance principles, these ecological principles can inform the designation and siting of ocean uses and the management of activities in the ocean to maintain or restore healthy ecosystems, allow delivery of marine ecosystem services, and ensure sustainable economic and social benefits.     

Sensitivity of crop yields and land resource potential to climatic change in Ontario,Canada

Increasing concentrations of atmospheric CO₂ and other greenhouse gases are expected to contribute to a global warming. This paper examines the potential implications of a climatic change corresponding to a doubling of atmospheric concentrations of CO₂ on crop production opportunities throughout Ontario, a major food producing region in Canada. The climate is projected to become warmer and drier, but the extent of these shifts are expected to vary from region to region within Ontario. The effect of this altered climate on crop yields and the area of land capable of supporting specific crops varies according to region, soil quality and crop type. Most notable are the enhanced opportunities for grains and oilseeds in the northern regions, and the diminished production prospects for most crops in the most southerly parts of Ontario.     

Shape analysis of Pacific seamounts

Shape statistics have been compiled from 85 profiles of well-surveyed Pacific seamounts in the height range 140–3800 m. A flat-topped cone was fit to each seamount's cross-sectional profile maintaining the slopes of the sides as closely as possible. On each profile a basal widthd_b, a summit widthd_t, and a maximum heighth, were measured. The height-to-basal-radius ratio isξ_h is estimated by the ratio2hd_b and flatnessf by the ratiod_td_b. Slope angleφ = arctan(ε) is estimated fromε =2h(d_b − d_t). Summit height and basal radius are found to be highly correlated (r = 0.93). The 85-point sample mean of the height-to-basal-radius ratio isξ_h = 0.21 ± 0.08 implying that a seamount's summit height is typically one fifth its basal radius. Despite the high correlation, individual points show some scatter, and there may be groupings into different morphological types. For example, all but one of the seamounts with summit heights above 1000 m have values ofξ_h that are larger than the sample mean. The 85-point sample mean of flatness isf = 0.31 ± 0.18. Data points show a large scatter with values off varying between 0 (a pointy cone) and 0.69 (a flat-topped cone). A histogram representation of flatness, however, indicates that certain values off may be more common than others: the histogram shows a bimodal distribution with maxima occurring at values off in the ranges 0.10–0.20 and 0.35–0.50. Moreover, there is some evidence that the mean flatness decreases with summit height so that the preferred shape of a large-sized seamount may be a pointy cone. Slope angle has an 85-point sample mean ofφ = 18 ± 6°; individual values ofφ vary between 5° and 36°. In addition to having a lower than average mean flatness seamounts with heights above 2600 m also have a lower than average mean slope angle (15°). To determine which variables account for most of the observed variation in the seamount shapes, a multivariate principal component analysis was performed on the data using five shape variables (summit height, basal radius, summit radius, flatness, and slope). The analysis indicates that most of the variation is described by two variables: flatness and summit height.     

Swelling capacity and permeability of an unprocessed and a processed bentonitic clay

Research on the longevity of potential bentonite-based barrier materials is an important part of the Canadian Nuclear Fuel Waste Management Program. Valuable information on the longterm effectiveness of bentonitic barriers can be obtained by examining the properties of unprocessed bentonites from natural deposits. This study compares the swelling capacity (P_s) and hydraulic conductivity (K) of an unprocessed (clay that has not been ground and dried by the supplier) and a processed bentonite from south-central Saskatchewan, Canada. The clay deposit is 75 to 85 Ma old. At a given clay density, the processed bentonite exhibits a greater P₃ and a lower K than the unprocessed clay. This can be at least partially attributed to the partial cementation of the unprocessed bentonite particles; this cementation is likely ruptured when the clay is ground during processing. Even though K for the unprocessed clay is higher than that of the processed clay, it is still low enough (< 10¹¹m/s) to meet the permeability requirements of a barrier material in a nuclear fuel waste disposal vault. The unprocessed clay also has the has the ability to self seal: exposure to water, the normalized flow rate of water through some samples was as high as 10^-5 m³/s, but the rate rapidly decreased to < 10^-10m³/s the clay absorbed water and swelled. The data indicate that the unprocessed bentonite clay maintains anacceptably high swelling capacity and low permeability millions of years after deposition.     

Yucatan after the wind: Human and environmental impact of hurricane Gilbert in the central and Eastern Yucatan Peninsula

Hurricane Gilbert made its landfall on the Yucatan peninsula on September 14, 1988, destroying valuable resort property in Cancun, Isla Mujeres, and Cozumel. Salt flats (salinas) in northern Quintana Roo and Yucatan were flooded by the storm surge and coastal marine ecosystem were devastated. Inland, the hurricane caused damages to houses, power lines, and farming land, but increased opportunities for garden hunting on destroyed fields. Twenty percent of tropical rain forest suffered losses of canopy and in the deciduous forests of north-central Yucatan noxiuous insects populations increased. Although damaging in its ultimate effects, hurricane Gilbert tested the resilience of Maya Indians and their readiness for post-disaster accommodation.     

Context and environment in taphonomic analysis: Examples from Alaska's Porcupine River Caves

Field investigations of caves along Alaska's Porcupine River document three major mechanisms which modify bone in patterns similar to alterations produced by man: (1) carnivore fracture; (2) rodent gnawing; and (3) rock fall and rubble scarring. A late Wisconsin faunal assemblage composed of Equus sp., Rangifer tarandus, Ovis dalli, Bison sp., proboscidean, numerous small mammal species, birds, and fish is well documented. This faunal assemblage suggests a mosaic environment of grassland-tundra-forest in the immediate vicinity of these caves and implies that the late Wisconsin environment in north-central Alaska may have been characterized by a number of microenvironments and colder, dryer, steppe conditions. Taphonomic data which have historically been interpreted to support human occupation of eastern Beringia during the Pleistocene are critically examined and the context of these discoveries (not the specimens themselves) provides the test essential to document the antiquity of man in North America prior to 12,000 yr ago.