No abstract

While we have learned much about the flycatcher over this 10-year study, there are still many important areas for future research. These include: whether small populations have different population dynamics than the large populations we studied; development of improved or new demographic models to help guide complex management decisions; development of spatial models that link key determinants of flycatcher habitat (e.g., groundwater, stream flow) to the characteristics of suitable habitat (as identified by our models); development of decision tools to conduct scenario planning and address management issues; the role and impact that emerging disease threats may have on flycatcher populations; and a better understanding of the migration ecology of flycatchers. Coordination with Arizona Game and Fish DepartmentThroughout this research effort, project leaders and field staff of the USGS and AGFD worked cooperatively to collect the data upon which this report and other related science products are based. AGFD and USGS had concurrent field crews working within the same study sites at Roosevelt Lake and

The jaguar (Panthera onca) is an endangered species that occasionally visits the southwestern United States from Mexico. The number of jaguar sightings per decade has declined over the last 100 years in Arizona, USA, raising conservation concerns for the species at a local and national level. In 1997, state, federal, and local governments with land‐management responsibilities agreed to characterize and identify potential jaguar habitat in Arizona and New Mexico. Specifically, the objectives of our analysis were 2‐fold: (1) characterize potential jaguar habitat in Arizona from historic sighting records and (2) create a statewide habitat suitability map. We used a Geographic Information System (GIS) to characterize potential jaguar habitat by overlaying historic jaguar sightings (25) on landscape and habitat features believed important (e.g., vegetation biomes and series, elevation, terrain ruggedness, proximity to perennial or intermittent water sources, human density). The amount of Arizona (%) identified as potential jaguar habitat ranged from 21% to 30% depending on the input variables. Most jaguar sightings were in scrub grasslands between 1,220 and 1,829‐m elevation in southeastern Arizona, in intermediately to extremely rugged terrain, and within 10 km of a water source. Conservation efforts should focus on protecting the most suitable jaguar habitat in southeastern Arizona (i.e., Santa Cruz, Pima, Cochise, Pinal, Graham counties), travel corridors within and outside Arizona, and jaguar habitat in the Sierra Madres of Sonora, Mexico.

Priest Rapids Dam on the Columbia River produces large daily and hourly streamflow fluctuations throughout the Hanford Reach during the period when fall Chinook salmon Oncorhynchus tshawytscha are selecting spawning habitat, constructing redds, and actively engaged in spawning. Concern over the detrimental effects of these fluctuations prompted us to quantify the effects of variable flows on the amount and persistence of fall Chinook salmon spawning habitat in the Hanford Reach. Specifically, our goal was to develop a management tool capable of quantifying the effects of current and alternative hydrographs on predicted spawning habitat in a spatially explicit manner. Toward this goal, we modeled the water velocities and depths that fall Chinook salmon experienced during the 2004 spawning season, plus what they would probably have experienced under several alternative (i.e., synthetic) hydrographs, using both one‐ and two‐dimensional hydrodynamic models. To estimate spawning habitat under existing or alternative hydrographs, we used cell‐based modeling and logistic regression to construct and compare numerous spatial habitat models. We found that fall Chinook salmon were more likely to spawn at locations where velocities were persistently greater than 1 m/s and in areas where fluctuating water velocities were reduced. Simulations of alternative dam operations indicate that the quantity of spawning habitat is expected to increase as streamflow fluctuations are reduced during the spawning season. The spatial habitat models that we developed provide management agencies with a quantitative tool for predicting, in a spatially explicit manner, the effects of different flow regimes on fall Chinook salmon spawning habitat in the Hanford Reach. In addition to characterizing temporally varying habitat conditions, our research describes an analytical approach that could be applied in other highly variable aquatic systems.

Subyearling fall Chinook salmon (Oncorhynchus tshawytscha) in the Columbia River basin exhibit a transient rearing strategy and depend on connected shoreline habitats during freshwater rearing. Impoundment has greatly reduced the amount of shallow‐water rearing habitat that is exacerbated by the steep topography of reservoirs. Periodic dredging creates opportunities to strategically place spoils to increase the amount of shallow‐water habitat for subyearlings while at the same time reducing the amount of unsuitable area that is often preferred by predators. We assessed the amount and spatial arrangement of subyearling rearing habitat in Lower Granite Reservoir on the Snake River to guide future habitat improvement efforts. A spatially explicit habitat assessment was conducted using physical habitat data, two‐dimensional hydrodynamic modelling and a statistical habitat model in a geographic information system framework. We used field collections of subyearlings and a common predator [smallmouth bass (Micropterus dolomieu)] to draw inferences about predation risk within specific habitat types. Most of the high‐probability rearing habitat was located in the upper half of the reservoir where gently sloping landforms created low lateral bed slopes and shallow‐water habitats. Only 29% of shorelines were predicted to be suitable (probability >0.5) for subyearlings, and the occurrence of these shorelines decreased in a downstream direction. The remaining, less suitable areas were composed of low‐probability habitats in unmodified (25%) and riprapped shorelines (46%). As expected, most subyearlings were found in high‐probability habitat, while most smallmouth bass were found in low‐probability locations. However, some subyearlings were found in low‐probability habitats, such as riprap, where predation risk could be high. Given their transient rearing strategy and dependence on shoreline habitats, subyearlings could benefit from habitat creation efforts in the lower reservoir where high‐probability habitat is generally lacking. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.