Valerie I. Cullinan

A comparison of quantitative methods for examining landscape pattern and scale

Ecologists have long recognized the importance of spatial and temporal patterns that characterize heterogeneity in landscapes. However, despite the realization that inferences about ecological phenomena are scale dependent, little attention has been paid to determining appropriate scales of measurement (e.g., plot or grain size) in studies of landscape dynamics or ecosystem change. This paper compares the results from three data sets using several quantitative methods available for characterizing landscape heterogeneity and/or for determining scale of measurement. Methods evaluated include tests of non-randomness, estimation of patch size, spectral analysis, fractals, variance ratio analysis, and correlation analysis. The results showed that no one method provides consistently good estimates of scale. Thus, sampling strategies for landscape studies should be derived from estimates of patch size and/or scale of pattern obtained from more than one of these methods.

Multiple landscape scales: An intersite comparison

Vegetation transect data from three locations were analyzed to determine if multiple scales of pattern could be detected. The sites included a semiarid grassland in New Mexico, a series of calcareous openings in a deciduous forest in Tennessee, and a shrub-steppe system in Washington. The data were explored with four statistical techniques. A scale of pattern was accepted if detected by more than one analytical method or located by a single method in multiple taxa. The analyses indicated 3–5 scales of pattern on all three sites, as predicted by Hierarchy Theory.

Determination of ecological scale

We suggest that ecological processes and physical characteristics possess an inherent scale at which the processes or characteristics occur over the landscape. We propose a conceptual spatial response model that describes the nature of this ecological scale. Based on the proposed spatial model, we suggest methods for estimating the size of study plots or transects and the distance between replicate plots needed to approach statistical independence. Using data on percent cover for Agropyron spicatum, a common arid-land bunchgrass, we demonstrated four relationships that should hold if the spatial response model is appropriate. These relationships are sample variance increases as functions of (1) transect segment length and (2) intersegment length (transect segment dispersal), and correlation decreases as functions of (3) intersegment length and (4) transect segment length. Based on evaluation of these four relationships, cover for A. spicatum is correlated over the landscape on a scale of 400 to 700 m, and a segment length of 64 to 128 m is most appropriate for measuring cover for this species.

The Use of Electromyogram Telemetry to Estimate Energy Expenditure of Adult Fall Chinook Salmon

Abstract Excess energy expenditure during the upstream migration of adult fall chinook salmon Oncorhynchus tshawytscha may reduce spawning success or lead to increased prespawning mortality. Recent advances in biotelemetry make it possible to assess the energetic costs of upstream migration. Our objectives were to evaluate the use of physiological telemetry to estimate the energy expended by adult fall chinook salmon at different swimming velocities and to compare these data to those associated with other species of salmonids. An electromyogram (EMG) telemetry system was used to obtain, transmit, and record an integrated EMG pulse signal that represented the time between muscle contractions. The EMG telemetry system provides a means to evaluate the effects of structural or operational changes in the hydropower system on energy expenditure and reproductive success of upstream migrant adult salmon. Seven adult salmon (71.5 to 106 cm fork length [FL]) were tagged and exercised in a respirometer at 15 and 20°...

A Bayesian test of hierarchy theory: scaling up variability in plant cover from field to remotely sensed data

Hierarchy theory predicts that a hierarchy of process rates should be reflected in a hierarchy of spatial and temporal scales observable on the landscape. We will show that multiple scales of pattern for total plant cover measured in the field at 1-m resolution are correlated with scales of vegetative pattern obtained from remotely sensed data with resolutions of 25 m2 and 30 2. Second, using four models based on postulates of hierarchy theory, we will combine the scales of pattern of each individual species within a community to estimate the remotely sensed community scales of pattern. Finally, we will compare the four models using a Bayesian analysis to determine which model best portrays how vegetative patterns of individual species combine to produce remotely observed community patterns. The results of the model comparisons provide an example of how postulates of hierarchy theory can be tested and how individual species patterns can be scaled-up to estimate remotely observed scales of pattern.

Satellite imagery as a tool to evaluate ecological scale

Methods for detecting scale and dispersion of plant cover developed by Carilieet al. (1989,Landscape Ecology 2: 203–213) were adapted to information obtained from satellite imagery. Scales were found to be on the order of 100 m in the shrub-steppe area of southeastern Washington. General agreement between the remotely sensed data and plant cover using the variance and correlation methods of Carlileet al. indicate that remote sensing information can be used in the design of field studies for measuring the processes controlling plant cover in semi-arid areas; the agreement also suggests that the methods have broad applicability in the determination of scale and dispersion.

The Effects of Total Dissolved Gas on Chum Salmon Fry Survival, Growth, Gas Bubble Disease, and Seawater Tolerance

Abstract Chum Salmon Oncorhynchus keta alevins developing in gravel downstream of Bonneville Dam on the Columbia River are exposed to elevated total dissolved gas (TDG) when water is spilled to move migrating salmon smolts to the ocean. We studied whether alevins that were exposed to six levels of dissolved gas ranging from 100% to 130% TDG at three development periods between hatch and emergence (hereafter, early, middle, and late stages) experienced differential mortality, growth, gas bubble disease, or seawater tolerance. Each life stage was exposed for 49 d (early stage), 28 d (middle stage), or 15 d (late stage) beginning at 13, 34, and 47 d posthatch, respectively, through emergence. Mortality for all stages was estimated to be 8% (95% confidence interval [CI] = 4–12%) when dissolved gas levels were less than 117% TDG. Mortality increased as dissolved gas levels rose above 117% TDG; the lethal concentration producing 50% mortality was 128.7% TDG (95% CI = 127.2–130.3% TDG) in the early and middle st...

Lower Columbia River and Estuary Ecosystem Restoration Program Reference Site Study: 2011 Restoration Analysis - FINAL REPORT

The Reference Site (RS) study is part of the research, monitoring, and evaluation (RME) effort developed by the Action Agencies (Bonneville Power Administration [BPA], U.S. Army Corps of Engineers, Portland District [USACE], and U.S. Bureau of Reclamation) in response to Federal Columbia River Power System (FCRPS) Biological Opinions (BiOp). While the RS study was initiated in 2007, data have been collected at relatively undisturbed reference wetland sites in the LCRE by PNNL and collaborators since 2005. These data on habitat structural metrics were previously summarized to provide baseline characterization of 51 wetlands throughout the estuarine and tidal freshwater portions of the 235-km LCRE; however, further analysis of these data has been limited. Therefore, in 2011, we conducted additional analyses of existing field data previously collected for the Columbia Estuary Ecosystem Restoration Program (CEERP) - including data collected by PNNL and others - to help inform the multi-agency restoration planning and ecosystem management work underway in the LCRE.

Two-dimensional thermal video analysis of offshore bird and bat flight

Abstract Thermal infrared video can provide essential information about bird and bat activity for risk assessment studies, but the analysis of recorded video can be time-consuming and may not extract all of the available information. Automated processing makes continuous monitoring over extended periods of time feasible, and maximizes the information provided by video. This is especially important for collecting data in remote locations that are difficult for human observers to access, such as proposed offshore wind turbine sites. We developed new processing algorithms for single camera thermal video that automate the extraction of two-dimensional bird and bat flight tracks, and that characterize the extracted tracks to support animal identification and behavior inference. The algorithms consist of video peak store followed by background masking and perceptual grouping to extract flight tracks. The extracted tracks are automatically quantified in terms that could then be used to infer animal taxonomy and possibly behavior, as described in the companion article from Cullinan, et al. [“Classification of birds and bats using flight tracks.” Ecological Informatics, 27:55–63]. The developed automated processing was evaluated using six video clips containing a total of 184 flight tracks. The detection rate was 81% and the false positive rate was 17%. In addition to describing the details of the algorithms, we suggest models for interpreting thermal imaging information.

Shallow Tidal Freshwater Habitats of the Columbia River: Spatial and Temporal Variability of Fish Communities and Density, Size, and Genetic Stock Composition of Juvenile Chinook Salmon

AbstractWe investigated the spatial and temporal variability of the fish community and the density, size, and genetic stock composition of juvenile Chinook Salmon Oncorhynchus tshawytscha in shallow tidal freshwater habitats of the Columbia River. We sought to address data gaps related to juvenile Chinook Salmon in this portion of the Columbia River and thereby inform habitat restoration efforts. We examined fish communities, juvenile salmon life history characteristics, and relationships between salmon density and habitat conditions by using beach seine data collected over a 63-month period (2007−2012) from two tidal freshwater areas: the Sandy River delta (river kilometer [rkm] 188–202) and the lower river reach (rkm 110–141). We found few differences in the fish community across the two study areas. Fish community patterns were largely attributable to seasonal changes as opposed to spatial gradients and habitat types. Juvenile Chinook Salmon were the most common salmon species in our catches; this spec...