Paleoindian seafaring, maritime technologies, and coastal foraging on California's Channel Islands.

Three archaeological sites on California's Channel Islands show that Paleoindians relied heavily on marine resources. The Paleocoastal sites, dated between ~12,200 and 11,200 years ago, contain numerous stemmed projectile points and crescents associated with a variety of marine and aquatic faunal remains. At site CA-SRI-512 on Santa Rosa Island, Paleocoastal peoples used such tools to capture geese, cormorants, and other birds, along with marine mammals and finfish. At Cardwell Bluffs on San Miguel Island, Paleocoastal peoples collected local chert cobbles, worked them into bifaces and projectile points, and discarded thousands of marine shells. With bifacial technologies similar to those seen in Western Pluvial Lakes Tradition assemblages of western North America, the sites provide evidence for seafaring and island colonization by Paleoindians with a diversified maritime economy.

Proximity of food retailers to schools and rates of overweight ninth grade students: an ecological study in California.

BACKGROUND: The prevalence of obesity and overweight in youth has increased dramatically since the 1980s, and some researchers hypothesize that increased consumption of low-nutrient, energy-dense foods is a key contributor. The potential importance of food retailers near schools has received increasing attention, but public health research and policy has focused primarily on fast food restaurants. Less is known about the relationship between overweight/obesity and other types of retailers. This study aims to investigate the potential associations between nearby 1) fast food restaurants, 2) convenience stores, and 3) supermarkets, and rates of overweight students in California schools. METHODS: We examined the rate of overweight ninth grade students in public schools in 2007 using linear regression. The percentage of overweight students per school was determined by a state required physical fitness test, with three different options for measuring individual body composition. Our key independent variables were the presence of three different types of retailers within 800 m network buffers of the schools. Additional independent variables included school ethnic, gender and socioeconomic composition, as well as urban/non-urban location. We obtained the data from the California Department of Education and ESRI, Inc. RESULTS: The presence of a convenience store within a 10-minute walking distance of a school was associated with a higher rate of overweight students than schools without nearby convenience stores, after controlling for all school-level variables in the regression (1.2%, 95% confidence interval 0.03, 2.36). Nearby fast food restaurants and supermarkets, however, were not associated with school rates of overweight students. CONCLUSIONS: Public health researchers and policy-makers interested in the food environments outside schools should expand their recent focus on nearby fast food restaurants to include convenience stores, which may also be important sources of low-nutrient, energy-dense foods for students.

Spatial relationships between water quality and pesticide application rates in agricultural watersheds.

Pesticide applications to agricultural lands in California, USA, are reported to a central data base, while data on water and sediment quality are collected by a number of monitoring programs. Data from both sources are geo-referenced, allowing spatial analysis of relationships between pesticide application rates and the chemical and biological condition of water bodies. This study collected data from 12 watersheds, selected to represent a range of pesticide usage. Water quality parameters were measured during six surveys of stream sites receiving runoff from the selected watershed areas. This study had three objectives: to evaluate the usefulness of pesticide application data in selecting regional monitoring sites, to provide information for generating and testing hypotheses about pesticide fate and effects, and to determine whether in-stream nitrate concentration was a useful surrogate indicator for regional monitoring of toxic substances. Significant correlations were observed between pesticide application rates and in-stream pesticide concentrations (p < 0.05) and toxicity (p < 0.10). In-stream nitrate concentrations were not significantly correlated with either the amount of pesticides applied, in-stream pesticide concentrations, or in-stream toxicity (all p > 0.30). Neither total watershed area nor the area in which pesticide usage was reported correlated significantly with the amount of pesticides applied, in-stream pesticide concentrations, or in-stream toxicity (all p > 0.14). In-stream pesticide concentrations and effects were more closely related to the intensity of pesticide use than to the area under cultivation.

Modeled regional climate change and California endemic oak ranges.

In the coming century, anthropogenic climate change will threaten the persistence of restricted endemic species, complicating conservation planning. Although most efforts to quantify potential shifts in species' ranges use global climate model (GCM) output, regional climate model (RCM) output may be better suited to predicting shifts by restricted species, particularly in regions with complex topography or other regionally important climate-forcing factors. Using a RCM-based future climate scenario, we found that potential ranges of two California endemic oaks, Quercus douglasii and Quercus lobata, shrink considerably (to 59% and 54% of modern potential range sizes, respectively) and shift northward. This result is markedly different from that obtained by using a comparable GCM-based scenario, under which these species retain 81% and 73% of their modern potential range sizes, respectively. The difference between RCM- and GCM-based scenarios is due to greater warming and larger precipitation decreases during the growing season predicted by the RCM in these species' potential ranges. Based on the modeled regional climate change, <50% of protected land area currently containing these species is expected to contain them under a future midrange "business-as-usual" path of greenhouse gas emissions.