Understanding the drivers of species occurrence is a fundamental goal in basic and applied ecology. Occupancy models have emerged as a popular approach for inferring species occurrence because they account for problems associated with imperfect detection in field surveys. Current models, however, are limited because they assume covariates are independent...
High-elevation aquatic ecosystems are highly vulnerable to climate change, yet relatively few records are available to characterize shifts in ecosystem structure or their underlying mechanisms. Using a long-term data set on seven alpine lakes (3126 to 3620 m) in Colorado, USA, we show that ice-off dates have shifted 7 days earlier over...
The role of each habitat fish use is of great importance to the dynamics of populations. During
their early marine residence, Chinook salmon (Oncorhynchus tshawytscha), an anadromous fish
species, mostly inhabit estuaries but also use sandy beach surf zones and the coastal ocean.
However, the role of surf zones in...
Large quantities of smaller diameter materials are available in the overstocked forests of eastern Oregon and Washington, but the costs of removing these materials and the long distances from markets sharply reduce the potential of this resource. Failure to thin these forests will sharply increase the likelihood of catastrophic wildfires....
The inter-relationships among δ¹³C and δ¹⁸O in tree ring cellulose and ring width have the potential to illuminate long-term physiological and environmental information in forest stands that have not been monitored. We examine how within-stand competition and environmental gradients affect ring widths and the stable isotopes of cellulose. We utilize...
The behavior of low-frequency baroclinic Rossby wave motion in the vicinity of coastal boundaries is investigated using linearized modulated wave theory in a stratified, constant-depth, equatorial β-plane ocean. A primary objective is to obtain an equation that describes large-scale, low-frequency pressure fluctuations along variable geometry ocean boundaries at all latitudes...
Stable isotopes can be a valuable tool for tracing the redistribution, storage, and evaporation of water associated with canopy
interception of rainfall. Isotopic differences between throughfall and rainfall have been attributed to three mechanisms:
evaporative fractionation, isotopic exchange with ambient vapor, and temporal redistribution. We demonstrate the potential
importance of...
Sandy beach surf zones serve as alternative nursery habitats for juvenile Chinook salmon (0 age) during their early marine residency, a period considered critical due to high and variable mortality rates. Despite the importance of early marine residence, the extent of juvenile salmon surf zone use and movement along sandy...
Glucose-dependent growth of the luxCDABE reporter bacterium Pseudomonas fluorescens HK44 was monitored noninvasively in quartz sand under unsaturated-flow conditions within a 45- by 56- by 1-cm two-dimensional light transmission chamber. The spatial and temporal development of growth were mapped daily over 7 days by quantifying salicylate-induced bioluminescence. A nonlinear model...
A novel analytical method was developed that permitted real-time, noninvasive measurements of microbial growth and associated changes in hydrodynamic properties in porous media under unsaturated flowing conditions. Salicylate-induced, lux gene-based bioluminescence was used to quantify the temporal and spatial development of colonization over a 7-day time course. Water contents were...