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Age-based population dynamics of Opuntia engelmannii, a shrubby cactus with flattened cladodes, were investigated at a Sonoran Desert site protected from grazing since 1907. Demographic statistics were determined from births and deaths on six permanent vegetation plots mapped four times between 1968 and 2001. Moderate longevity (13–56 years) and modest per capita annual survival (0.9298) were associated with fairly rapid turnover; cycles of population growth and decline were thus evident over relatively short periods. Age–frequency distribution, determined for subpopulations in two neighboring habitats in 1996 and 2003, was used to calculate residual regeneration, an index of the difference between observed cohort...
In the northern Colorado Front Range, fire suppression during the 20th century is believed to have created a high hazard of catastrophic fire in ponderosa pine (Pinus ponderosa) forests. Since the early 1990s, resource managers have increased the use of prescribed fires to re-create fire regimes and forest structures similar to those of the pre-Euro-American settlement period in order both to reduce fire hazard and to improve forest health. To improve understanding of historical fire regimes, we conducted a study of fire history along an elevational gradient from \sim1830 to 2800 m in ponderosa pine forests in the northern Front Range. Fire-scar dates were determined from 525 partial cross sections from living and...
This data release contains mean high water (MHW) shorelines for sandy beaches along the coast of California for the years 1998/2002, 2015, and 2016. The MHW elevation in each analysis region (Northern, Central, and Southern California) maintained consistency with that of the National Assessment of Shoreline Change. The operational MHW line was extracted from Light Detection and Ranging (LiDAR) digital elevation models (DEMs) using the ArcGIS smoothed contour method. The smoothed contour line was then quality controlled to remove artifacts, as well as remove any contour tool interpretation of human-made infrastructure (such as jetties, piers, and sea walls), using satellite imagery from ArcGIS.
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These data are records collected from six automated weather stations in operation between January 1, 2014 and December 31, 2015 within the Colorado River Corridor of Grand Canyon National Park and Glen Canyon National Recreation Area. Data collection locations, equipment configurations and methods follow those of the original report (OFR 2014-1247). These files are 4-minute interval data for each of the automated weather stations, tab separated by parameter (wind direction, wind speed, wind gusts, air temperature, relative humidity, barometric pressure, and rainfall). Climatic conditions during the reporting period were warm and dry early in 2014 and transitioned to average to slightly above precipitation from mid-2014...
This dataset contains California shoreline change rates derived from mean high water (MHW) shorelines from 1998 (in Central and Southern California) and 2002 (in Northern California) to 2016. The MHW elevation in each analysis region (Northern, Central, and Southern California) maintained consistency with that of the National Assessment of Shoreline Change. The operational MHW line was extracted from Light Detection and Ranging (LiDAR) digital elevation models (DEMs) using the ArcGIS smoothed contour method. Within the Digital Shoreline Analysis System (DSAS), end-point rates (EPR) of shoreline change were calculated between the 1998/2002 and the 2016 shorelines at a transect spacing of 50 meters to provide a long-term...
This dataset contains shoreline change measurements for sandy beaches along the coast of California over the 2015/2016 El Nino winter season. Mean high water (MHW) shorelines were extracted from Light Detection and Ranging (LiDAR) digital elevation models from the fall of 2015 and the spring of 2016 using the ArcGIS smoothed contour method. The MHW elevation in each analysis region (Northern, Central, and Southern California) maintained consistency with that of the National Assessment of Shoreline Change. Within the Digital Shoreline Analysis System (DSAS), the net shoreline movement (NSM) between the pre-El Nino (2015) and post-El Nino (2016) shorelines was calculated at a transect spacing of 50 meters as a proxy...


    map background search result map search result map Meteorological Data for Selected Sites along the Colorado River Corridor, Arizona, 2014-2015 Mean high water (MHW) shorelines along the coast of California used to calculated shoreline change from 1998 to 2016 Shoreline change rates along the coast of California from 1998 to 2016 Shoreline change data along the coast of California from 2015 to 2016 Meteorological Data for Selected Sites along the Colorado River Corridor, Arizona, 2014-2015 Shoreline change rates along the coast of California from 1998 to 2016 Shoreline change data along the coast of California from 2015 to 2016 Mean high water (MHW) shorelines along the coast of California used to calculated shoreline change from 1998 to 2016