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David F. Delaney

Publications and source records attributed to David F. Delaney.

14 recordsLinked to original sources
USGS2017

Mammalian mesocarnivore visitation at tortoise burrows in a wind farm

There is little information on predator–prey interactions in wind energy landscapes in North America, especially among terrestrial vertebrates. Here, we evaluated how proximity to roads and wind turbines affect mesocarnivore visitation with desert tortoises ( Gopherus agassizii ) and their burrows in a wind energy landscape. In 2013, we placed motion-sensor cameras facing the entrances of 46 active desert tortoise burrows in a 5.2-km 2 wind energy facility near Palm Springs, California, USA. Cameras recorded images of 35 species of reptiles, mammals, and birds. Counts for 4 species of mesocarnivores at desert tortoise burrows increased closer to dirt roads, and decreased closer to wind turbines. Our results suggest that anthropogenic infrastructure associated with wind energy facilities could influence the general behavior of mammalian predators and their prey. Further investigation of proximate mechanisms that underlie road and wind turbine effects (i.e., ground vibrations, sound emission, and traffic volume) and on wind energy facility spatial designs (i.e., road and wind turbine configuration) could prove useful for better understanding wildlife responses to wind energy development. © 2017 The Wildlife Society.

California↗
USGS2015

Turbines and terrestrial vertebrates: variation in tortoise survivorship between a wind energy facility and an adjacent undisturbed wildland area in the desert southwest (USA)

With the recent increase in utility-scale wind energy development, researchers have become increasingly concerned how this activity will affect wildlife and their habitat. To understand the potential impacts of wind energy facilities (WEF) post-construction (i.e., operation and maintenance) on wildlife, we compared differences in activity centers and survivorship of Agassiz's desert tortoises ( Gopherus agassizii ) inside or near a WEF to neighboring tortoises living near a wilderness area (NWA) and farther from the WEF. We found that the size of tortoise activity centers varied, but not significantly so, between the WEF (6.25 ± 2.13 ha) and adjacent NWA (4.13 ± 1.23 ha). However, apparent survival did differ significantly between the habitat types: over the 18 year study period apparent annual survival estimates were 0.96 ± 0.01 for WEF tortoises and 0.92 ± 0.02 for tortoises in the NWA. High annual survival suggests that operation and maintenance of the WEF has not caused considerable declines in the adult population over the past two decades. Low traffic volume, enhanced resource availability and decreased predator populations may influence annual survivorship at this WEF. Further research on these proximate mechanisms and population recruitment would be useful for mitigating and managing post-development impacts of utility scale wind energy on long-lived terrestrial vertebrates.

Environmental Management↗
USGS2015

Using motion-sensor camera technology to infer seasonal activity and thermal niche of the desert tortoise ( Gopherus agassizii )

Understanding the relationships between environmental variables and wildlife activity is an important part of effective management. The desert tortoise ( Gopherus agassizii ), an imperiled species of arid environments in the southwest US, may have increasingly restricted windows for activity due to current warming trends. In summer 2013, we deployed 48 motion sensor cameras at the entrances of tortoise burrows to investigate the effects of temperature, sex, and day of the year on the activity of desert tortoises. Using generalized estimating equations, we found that the relative probability of activity was associated with temperature (linear and quadratic), sex, and day of the year. Sex effects showed that male tortoises are generally more active than female tortoises. Temperature had a quadratic effect, indicating that tortoise activity was heightened at a range of temperatures. In addition, we found significant support for interactions between sex and day of the year, and sex and temperature as predictors of the probability of activity. Using our models, we were able to estimate air temperatures and times (days and hours) that were associated with maximum activity during the study. Because tortoise activity is constrained by environmental conditions such as temperature, it is increasingly vital to conduct studies on how tortoises vary their activity throughout the Sonoran Desert to better understand the effects of a changing climate.

California↗
USGS2015

Nelson's big horn sheep ( Ovis canadensis nelsoni ) trample Agassiz's desert tortoise ( Gopherus agassizii ) burrow at a California wind energy facility

Research on interactions between Agassiz's desert tortoises ( Gopherus agassizii ) and ungulates has focused exclusively on the effects of livestock grazing on tortoises and their habitat (Oldemeyer, 1994). For example, during a 1980 study in San Bernardino County, California, 164 desert tortoise burrows were assessed for vulnerability to trampling by domestic sheep ( Ovis aries ). Herds of grazing sheep damaged 10% and destroyed 4% of the burrows (Nicholson and Humphreys 1981). In addition, a juvenile desert tortoise was trapped and an adult male was blocked from entering a burrow due to trampling by domestic sheep. Another study found that domestic cattle ( Bos taurus ) trampled active desert tortoise burrows and vegetation surrounding burrows (Avery and Neibergs 1997). Trampling also has negative impacts on diversity of vegetation and intershrub soil crusts in the desert southwest (Webb and Stielstra 1979). Trampling of important food plants and overgrazing has the potential to create competition between desert tortoises and domestic livestock (Berry 1978; Coombs 1979; Webb and Stielstra 1979).

Bulletin of the Southern California Academy of Sci↗
USGS1981

Hydrologic data of the lower Merrimack River basin, Massachusetts, from Concord River, Lowell, to Plum Island, Newburyport

The lower Merrimack River basin study area drains approximately 180 square miles along the New Hampshire border in northeastern Massachusetts. This area includes parts of the Merrimack River basin within Massachusetts east of the Beaver Brook and Concord River basins, except for the Shawsheen River basin. Even though the Blackwater River basin within Massachusetts isn't part of the lower Merrimack River basin, it has been included in this report. Principal tributaries to the Merrimack River, which discharges to the Atlantic Ocean at Newburyport, Massachusetts, are: Bare Meadow, Bartlett, Cobbler Creek, Fish, Richardson, and Trull Brooks, Artichoke, East Meadow, Indian, Little, Powwow, and Spicket Rivers, and Johnson Creek.

Massachusetts↗
USGS1981

Hydrologic data of the Shawsheen River basin, Massachusetts

The Shawsheen River basin drains a 77-square-mile area northwest of metropolitan Boston in eastern Massachusetts and discharges into the Merrimack River. Principal tributaries to the Shawsheen River are: Content, Elm, Heath, Hussey, Kiln, Rogers, Spring, Strong Water, Vine, and Webb Brooks.

Massachusetts↗
USGS1980

Distribution of aquifers, liquid-waste impoundments, and municipal water-supply sources, Massachusetts

Impoundments of liquid waste are potential sources of ground-water contamination in Massachusetts. The map report, at a scale of 1 inch equals 4 miles, shows the idstribution of aquifers and the locations of municipal water-supply sources and known liquid-waste impoundments. Ground water, an important source of municipal water supply, is produced from shallow sand and gravel aquifers that are generally unconfined, less than 200 feet thick, and yield less than 2,000 gallons per minute to individual wells. These aquifers commonly occupy lowlands and stream valleys and are most extensive in eastern Massachusetts. Surface impoundments of liquid waste are commonly located over these aquifers. These impoundments may leak and allow waste to infiltrate underlying aquifers and alter their water quality. (USGS)

Open-File Report↗
USGS1979

Ground-water availability in parts of the Chicopee and Mill River basins, near Wilbraham, Massachusetts

Ground water in the Wilbraham area occurs in glacial drift and in underlying bedrock. Stratified sand and gravel deposits form the principal unconsolidated aquifers. These aquifers are generally less than 50 feet thick in most of the study area; however, an area in north-central Wilbraham, near the Chicopee River, is underlain by stratified drift deposits more than 200 feet thick that may be capable of yielding more than 300 gal/min (gallons per minute) to individual wells. Bedrock aquifers are generally of two types: Triassic and Jurassic sedimentary rock lies west of a north-south trending fault, and Paleozoic metamorphic, and igneous rock lies east of the fault. The median yield of wells in sedimentary bedrock is 15 gal/min; yields range from 2 to 110 gal/min. The median yield of wells in crystalline rock is 5 gal/min; yields range from less than 1 to 60 gal/min. (Woodard-USGS)

Massachusetts↗