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371. [Article] Effects of harvest and roads on in-stream wood abundance in the Blue River Basin, western Cascades, Oregon
Despite many studies of large wood in streams, few landscape scale studies have been conducted. Large-scale studies can reveal how the history of forest harvest and road building has influenced wood patterns ...Citation Citation
- Title:
- Effects of harvest and roads on in-stream wood abundance in the Blue River Basin, western Cascades, Oregon
- Author:
- Czarnomski, Nicole M.
Despite many studies of large wood in streams, few landscape scale studies have been conducted. Large-scale studies can reveal how the history of forest harvest and road building has influenced wood patterns in streams of the Pacific Northwest. This study examined the relationships between wood in streams, timber harvest, and road building at large (>50 km² ) spatial and long (>25 year) temporal scales, based on longitudinal surveys of 25.2 km of stream length in five sub-basins of the Blue River Basin, Cascade Range, Oregon. In-stream wood was surveyed in six sampling sites, ranging from 1.6 km to 14.1 km in length along 2nd to 5th -order channels in public forests. Wood volumes, numbers of pieces of large wood, numbers of accumulations and timing of emplacement were determined at 50-m intervals. Wood volumes and numbers of pieces were expressed per unit of channel area in order to account for variations in channel width. Wood volumes and piece numbers were related to spatial data on harvest and road building using GIS. Analysis of variance (using SAS) tested how wood volumes and piece numbers were related to the presence of a harvest or road unit within 40 m of the stream, sampling site, timing of harvest, distance harvest was from the channel, and effects of natural processes. P-values for pairwise comparisons were adjusted using a Bonfenoni procedure. Distributed patch clearcutting and road construction were concentrated in the 1950's and 1960's in the Lookout Creek basin and 1960's to the 1980's in the Upper Blue River basin. A total of 66% (Cook Creek), 55% (Mack Creek), 53% (Lower Lookout), 37% (McRae Creek and Upper Lookout), and 7% (Quentin Creek) of stream length had harvests and/or roads within 40 m of the stream. Approximately 80% of the wood volume and 85% of the number of large pieces occurred in accumulations. Wood volumes were lower in 5th-order compared to 3rd -order streams. Lower Lookout (the only 5th-order channel) had significantly lower wood volumes (109 m³/ha) than all other locations (200-378 m³/ha, p<O.O5) and significantly lower numbers of large pieces (23 large pieces/ha) compared to all other locations (39 vs. 64 large pieces/ha, p<O.008). All other locations had fairly similar wood volumes and numbers of large pieces For all study sites combined, 50-m stream segments without harvests or roads had significantly higher volume (356 m³/ha) and number of large pieces (57 pieces/ha), than stream segments with harvests or roads within 40 m (80 to 157 m³/ha, p<O.O3; 19 to 39 pieces/ha, p<O.O4). Stream segments without harvests or roads (32 pieces/ha) also had significantly higher number of accumulations compared to stream segments with roads (16 pieces/ha, p<O.004), or compared to stream segments with harvest on one side and roads (16 pieces/ha, p<O.004). Distance a harvest was from the stream and timing of harvest did not appear to affect wood volume or number of large pieces. Harvests and roads were associated with decreases in wood abundance 50 m upstream and 50 m downstream of harvest units and road crossings. The 50-m stream segments immediately upstream (171.8 m³/ha) and downstream (191.6 m³/ha) of a section of stream with harvest and roads had significantly lower volume than the 50-m stream segments without harvest or roads (427.7 m³/ha, p<O. 1). Natural processes such as floods, windthrow, near-stream toppling, and debris flows from the last 50 years had not obscured the effects of harvest and roads on wood volume and number of pieces in stream channels of Lookout Creek and Blue River. The legacy of harvest and road activities was still apparent in in-stream wood patterns up to 50 years later in this site, which consisted of old-growth forest subjected to dispersed patch clearcutting, road construction, and salvage logging conducted in the 1950's to the 1980s. However, harvest, road, and salvage practices on public lands have changed since that period. Therefore, these results should be extrapolated to other sites only with careful consideration of site history.
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372. [Article] Physiological ecology of juvenile Chinook salmon (Oncorhynchus tshawytscha) rearing in fluctuating salinity environments
Estuaries provide juvenile salmonids with highly productive feeding grounds, refugia from tidal fluctuations and predators, and acclimation areas for smoltification. However, these dynamic, fluctuating ...Citation Citation
- Title:
- Physiological ecology of juvenile Chinook salmon (Oncorhynchus tshawytscha) rearing in fluctuating salinity environments
- Author:
- Hackmann, Crystal R.
Estuaries provide juvenile salmonids with highly productive feeding grounds, refugia from tidal fluctuations and predators, and acclimation areas for smoltification. However, these dynamic, fluctuating salinity environments may also be physiologically stressful to growing juvenile fish. In order to evaluate the costs and benefits of estuarine marshes to juvenile Chinook salmon, I observed habitat use, diet, and growth of fish in the Nehalem Estuary on the Oregon coast. I also examined physiological costs associated with salmon living in fluctuating salinities and growth rates in laboratory experiments. I collected growth, diet and osmoregulation information from juvenile Chinook salmon in three tidal marsh sites in the Nehalem Bay and from juveniles in the Nehalem River. Stomach contents indicated that a high proportion of the diet is derived from terrestrial prey. These allochthonous prey resources likely become available during the flood stages of tidal cycles when drift, emergent and terrestrial insects would become available from the grasses surrounding the water. This field study confirmed that juvenile Chinook salmon utilized fluctuating salinity habitats to feed on a wide range of items including terrestrial-derived resources. Although field studies indicate that fish in estuarine habitats grow well and have access to quality prey resources, experimental manipulations of salinities were used to quantify the physiological costs of residing in the freshwater-saltwater transitional zone. In the laboratory, I designed an experiment to investigate the physiological responses to fluctuating salinities. Experimental treatments consisted of freshwater (FW), saltwater (SW) (22-25%o); and a fluctuating salinity (SW/FW) (2 - 25%o). These treatments were based on typical salinity fluctuations found in estuarine habitats. I measured length, weight, plasma electrolytes and cortisol concentrations for indications of growth and osmoregulatory function. The fluctuating salinity treatment had a negative effect on growth rate and initial osmoregulatory ability when compared with constant freshwater and saltwater treatments. The results indicated that fluctuating salinities had a small but marginally significant reduction in growth rate, possibly due to the additional energetic requirements of switching between hyper- and hypo-osmoregulation. However, 24-hour saltwater challenge results indicated that all fish were capable of osmoregulating in full-strength seawater. In a second experiment, I manipulated feed consumption rates of juvenile spring Chinook salmon to investigate the effects of variable growth rates on osmoregulatory ability and to test the validity of RNA:DNA ratios as indication of recent growth. The treatments consisted of three different feeding rates: three tanks of fish fed 0.7 5% (LOW) body weight; three tanks fed 3% (HIGH) body weight; and three tanks were fasted (NONE) during the experiment. These laboratory results showed a significant difference in the osmoregulatory ability of the NONE treatment compared to the LOW and HIGH treatments which indicates that a reduction in caloric intake significantly effected osmoregulatory capabilities during a 24 hour saltwater challenge. Furthermore, this suggests that there is a minimum energetic requirement in order to maintain proper ion- and osmoregulation in marine conditions. Estuarine marshes have the potential to provide productive feeding grounds with sufficient prey input from terrestrial systems. However, utilization of these marshes in sub-optimal conditions could alter behavior or impair physiological condition of juvenile Chinook salmon prior to their seaward migration by providing insufficient prey resources in a potentially stressful, fluctuating environment. Therefore, the physiological costs associated with estuarine habitat use should be well understood in order to aid future restoration planning.
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Shorebirds display great variation in mating systems and breed in dynamic environments that are increasingly subject to human threats worldwide. In order to adequately assess productivity and demography ...
Citation Citation
- Title:
- Incubation patterns, parental roles, and nest survival of black oystercatchers (Haematopus bachmani) : influences of environmental processes and potential disturbance stimuli
- Author:
- Spiegel, Caleb S.
Shorebirds display great variation in mating systems and breed in dynamic environments that are increasingly subject to human threats worldwide. In order to adequately assess productivity and demography of shorebird populations, it is important to understand factors that influence patterns of parental care and reproductive success. The Black Oystercatcher (Haematopus bachmani) is a shorebird species of concern and an indicator of the health of intertidal ecosystems. Much information on breeding biology is lacking for the species, though it is reported to regularly experience low reproductive success and may be vulnerable to human disturbance during nesting. This thesis examines relationships among natural and human processes related to incubation and nest success of Black Oystercatchers in a high density breeding area of Alaska, experiencing increasing human recreational activity. In 2005 and 2006, oystercatcher nests were continuously monitored with video cameras to investigate the association of cyclical (time of day, tide, ambient temperature, seasonality) and stochastic (natural/human disturbance) processes with incubation patterns (nest attendance, incubation bout length, incubation recess rate) and sex roles. Review of over 3,000 hours of footage from 13 molecularly sexed nesting pairs revealed complimentary bi-parental care with differing roles between sexes. Females allocated more to nest attendance and had longer incubation bout lengths, indicating a greater investment in incubation compared to males. Males responded more frequently to nest area disturbance stimuli compared to females, indicating that males invest more in nest defense. Incubation patterns were also influenced by tide stage and height, ambient temperature, and disturbance stimuli. Incubation bout lengths nearly doubled at night, independent of sex. Longer nocturnal bouts may minimize parental activity near the nest during periods of increased predation risk when incubation duty changes could reveal the presence of nests to nocturnal predators. Video footage was also used to document the types and frequencies of human and predator stimuli, and extreme weather and tide episodes encountered near oystercatcher nests, and the effect of these potential disturbance stimuli on incubation behavior and nest success. Nearly 800 potential disturbance stimulus events were documented within 25 m of video monitored nests. Other bird species were the most frequently observed type of potential disturbance, but were largely ignored by incubating oystercatchers. Oystercatchers were most frequently disturbed (as evidenced by displacement from a nest) by conspecifics and humans, with nests left unattended for longer periods following human disturbance than any other disturbance type. Although infrequent, a high proportion of mammal observations also resulted in oystercatchers flushing from their nests. Changes in incubation behavior due to disturbance were not found to affect nest success, nor did nest success decrease with proximity to areas of frequent human recreational activity. Nocturnal nest predation by mustelids and nighttime flood tides accounted for six of seven nest failures recorded on video, even though nights were disproportionately short during the study. Thus, future shorebird breeding studies should assess causes of nest failure from latent nocturnal causes, rather than just obvious diurnal causes. With the analysis of extensive nest observation data this study identified natural and anthropogenic processes that affected incubation patterns of an uncommon shorebird species, specially adapted to a dynamic nesting environment. Results elucidate factors influencing oystercatcher life history and lay the groundwork for further investigation into the effects of human disturbance on nest success and demography of the Black Oystercatcher. Future research should investigate nest success in breeding areas experiencing higher levels of disturbance, include post-hatching breeding stages, and be conducted over multiple breeding seasons.
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Giant otters (Pteronura brasiliensis) and humans in the Lower Yasuní Basin (Ecuador) have similar food and space requirements: they consume comparable arrays of fish species, and they use similar aquatic ...
Citation Citation
- Title:
- Giant otters (Pteronura brasiliensis) and humans in the lower Yasuní Basin, Ecuador : spacio-temporal activity patterns and their relevance for conservation
- Author:
- Carrera-Ubidia, Paola M.
Giant otters (Pteronura brasiliensis) and humans in the Lower Yasuní Basin (Ecuador) have similar food and space requirements: they consume comparable arrays of fish species, and they use similar aquatic and terrestrial habitats. Resource partitioning could facilitate coexistence by allowing each species exclusive access to some resources. My research examines the correlations between the use of spatial resources by giant otters and humans and the hydrological pulse of their ecosystem. My objectives were (1) to estimate the extent of terrestrial and aquatic habitat available for giant otters and humans;(2) to recognize the main patterns of space occupancy and its overlap between them; (3)to explain these patterns in relation to natural gradients in the watershed; (4) to describe the giant otter’s diet; and (5) to depict the foraging activities of giant otters and humans relative to the distribution of prey. Between October 2004 and March 2005, I surveyed the Jatuncocha and Tambococha Creeks (Yasuní National Park) for direct and indirect signs of giant otters and humans, and I collected giant otter scat. Habitat availability was estimated by a geo-referenced map model that integrated virtual and field data, portraying four seasonal scenarios. Space use overlaps between giant otters and humans are a function of water level and the distance between terrestrial and aquatic habitats. The floodplain comprises 43% of the total study area during the flooding season, and is reduced to 25% of the total area at minimum water levels. Polygons obtained containing suitable habitat for giant otters are in average 41% larger than those obtained for humans; these contain areas that are inaccessible to humans (isolated pools and swamps, tributaries, and the upper portions of the main channel). Differences in space availability for and use by giant otters and humans depend on water level fluctuations. Area occupancy by both species is proportional to the estimated availability; but more so for giant otters, as humans increase area occupancy during the driest periods. Giant otter activity was primarily concentrated around the largest tributaries of each creek, and secondarily wherever the distance between suitable terrestrial and aquatic habitat was smaller. Human activity signs were distributed along the hydrographical gradient, i.e. in the lower portion of the Jatuncocha System (lagoon) or in the middle portion of the Tambococha Creek (large tributary). To identify correlations between habitat use by giant otters and humans and prey availability, I analyzed scat samples and collected fish along several creek stretches. Giant otters consumed at least 47 of the 73 species available for them. Identifiable hard parts in the scat samples consisted primarily of Hoplias malabaricus (11.3%), Hypselecara termporalis (5.3%), Acestrorrhynchus sp. and Prochilodus nigricans (4.9% each). Foraging activity of giant otters was positively correlated with fish abundance and relative diversity, with some exceptions. Human activity patterns were related to fish abundance and diversity in Tambococha, but showed less correlation to fish distribution in Jatuncocha. Overlap in resource availability and habitat use by otters and humans is highly variable. In the floodplain, extent and depth are critical variables that determine the distribution of resources in time and space, as well as the amount of resource partitioning possible. Competitive interactions during stressful conditions could be reduced by ensuring the availability of exclusive resources for giant otters during the driest periods, allocating suitable habitats within a short distance from one another along the longitudinal gradient of each watershed. Locally adapted and biologically sound regulations within this and comparable areas of the YNP could promote the persistence of giant otters without compromising the well-being of the local human inhabitants.
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Tillamook Bay is the second largest estuary on the Oregon coast, and concerns have been raised whether human induced impacts have been responsible for the perceived increase in sedimentation rates during ...
Citation Citation
- Title:
- Sediment accumulation and human impacts in Tillamook Bay, Oregon
- Author:
- Styllas, Michael N.
Tillamook Bay is the second largest estuary on the Oregon coast, and concerns have been raised whether human induced impacts have been responsible for the perceived increase in sedimentation rates during the past century. Major land-use practices within the five watersheds of the Bay include logging, forest fires, the construction of forest roads, the placement of dikes along the channels of the main rivers and in the estuary, the removal of riparian vegetation, and the construction of jetties at the tidal inlet. Each of these practices has led to impacts on the entire ecosystem of the watersheds and the Bay, but this study focuses on the effects of human disturbances on the Bay's sediment accumulation. This study examines in detail the land-use practices that have occurred in the watersheds, on the beaches, and in the estuary, focusing on those that have had a direct impact on the sedimentation regime of the Bay. One goal of the study is to assess the relative roles of natural processes versus human impacts on the sedimentation. A general description of the physical characteristics of Tillamook Bay and its surroundings is included, and a brief discussion is provided about the tectonic setting of the Northwest Coast, including its history of subduction earthquakes and the associate sea-level changes. Also provided is a summary of the existing information concerning the arrival of Indians and their environmental impacts, followed by a more detailed account of the major impacts that have resulted from the settlement of the Euro-Americans in the Tillamook area, in the 1850's. The study then focuses on the description of the watersheds from a geomorphologic point of view, and the important land-use practices that may have affected sediment yields during the past century. Analyses of the hydrology of the Tillamook Bay watersheds are included, and the relations between annual water yields and total precipitation are examined in distinct time intervals, each corresponding to a different period with different amounts of land uses. The results of these hydrology analyses suggest that the Tillamook watershed gradually recovered from a period of major disturbances (from 1933 to 1955) to more normal conditions (from 1977 to 1998). In addition, this part of the study attempts to quantify the sediment transport regime of the rivers draining the watershed by using a hydraulic model that is based on the principle of stream power, and on considerations of availability of transported material. Application of this model during the 1933-1955 period for the major rivers suggests an average sediment yield on the order of 410,540 tons/year, but most important are the relative changes of the delivered sediment through time. The results of the model suggest a 1.6-factor decrease of the amount of river sediments from the Heavily Impacted Period (1933-1955) of major disturbances to the Normal Period (1977- 1998). The spatial variations of beach and river derived sediments throughout the Bay are determined from textural and mineralogical analyses of surface sediment samples, with the beach sands dominating the area close to the inlet and the river derived sands being mainly deposited at the southeast and northeast parts of the Bay. The relative contributions of these two major sources of sediment were found to be 60% for the marine beach and 40% for the river sands. Further attempt is made to distinguish between the sand transported into the Bay from the individual rivers, and to determine the main processes that are responsible for the dispersion of sediments within the Bay. The attempts to distinguish sands contributed by the individual rivers involved modal analyses of the frequency curves of the surface sediment samples, and the results mainly suggest a grain-size increase away from the mouth of the rivers as a result of sediment reworking by estuarine processes following its initial deposition during episodic river flooding. The main processes that control the dispersion of sediments and their deposition within the Bay were identified by using factor analysis, the results of which suggest that various estuarine processes are responsible for the observed dispersal patterns. A brief review is provided of the study undertaken by Dr. James McManus for the collection and analyses of core samples from Tillamook Bay. Down-core geochemical analyses of major and minor elements indicate that there have been times of episodic input of marine sediment in the central and western portions of the Bay, which is a result of either periodic breaching or washover of Bayocean Spit, so that the beach sand source was more important in the past. This episodic input of marine sand as inferred from the down-core geochemical variations was related to the most recent subduction earthquake, which occurred on January 26th, 1700. Finally, a summary of the results and conclusions of different aspects of this study is presented, so that sedimentation in Tillamook Bay can be viewed as an integrated process involving the watersheds, the estuary, and the ocean beaches.
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376. [Article] Some techniques for determining fecal output and digestibility of range forage by cattle
A Cr₂0₃, and cellulose fibre mixture was used with cattle, in three grazing and two semi-restricted experiments, to study the mode of its excretion, the possibility of using it in a once-daily dosing and grab-sample ...Citation Citation
- Title:
- Some techniques for determining fecal output and digestibility of range forage by cattle
- Author:
- Pryor, William Joseph
A Cr₂0₃, and cellulose fibre mixture was used with cattle, in three grazing and two semi-restricted experiments, to study the mode of its excretion, the possibility of using it in a once-daily dosing and grab-sample regime to estimate fecal output and in a field experiment to test a hypothesis involving the measurement of forage intake. The cattle consumed forages available in the sagebrush-bunchgrass region of Eastern Oregon, in which region the experiments were conducted. Cr₂0₃-Cellulose was fed to groups of three steers grazing immature crested wheatgrass, (Agropyron desertorum) in Experiment 1, or when it was mature along with regrowth in Experiment 2, either once a day at 8 a.m. or twice daily at 8 a.m. and 4 p.m. Twice a day grab sampling was carried out from 3-18 days after commencement of dosing with total collections from days 3-8 and 13-18. Estimated fecal outputs based on fecal grab sample concentrations at 8 a.m. alone, or the mean of 8 a.m. and 4 p.m. values were calculated in both experiments. Cr₂0₃ recoveries in Experiment 1 were low, ranging from 71.1-85.4 percent, with individual animals varying little between collection periods. Estimated fecal dry matter output was high in both groups for both collection periods and both sampling time methods, ranging from 115.7-187.3 percent. Standard errors of the mean (S.E.) were high in the 8 a.m. group in both collection periods, though not in the twice-daily group. Recoveries in Experiment 2 varied from 94.9-107.6 percent with an overall mean of 100.8 percent. The ratio of estimated fecal dry matter to that collected had high S.E.'s in the first period but gave the following results in the second period: 84.3 percent ± 4.5 percent S.E. for 8 a.m. dosing and sampling; 95.0 percent ± 1.5 percent for 8 a.m. and 4 p.m. dosing with 8 a.m. sampling; 97.1 percent ± 3.8 percent for 8 a.m. dosing and 8 a.m. and 4 p.m. sampling and 95.6 percent ± 2.0 percent for 8 a.m. and 4 p.m. dosing and sampling. The four-hourly Cr₂0₃ excretion curve of two groups of two long yearling heifers, two months pregnant, having continued access to flood meadow hay, was established by either once or twice daily dosing. The group dosed, once daily showed a relatively regular diurnal pattern, the twice-daily dosed group less so. The ratio of 8 a.m., and mean of 8 a.m. and 4 p.m. fecal Cr₂0₃ levels to daily mean four-hourly levels was established over a five-day period and showed a very close relationship to percentage estimates obtained in Experiment 2 for the 8 a.m. dosed and sampled group and to a slightly lesser extent to the other three groups. The excretion curve from a single ten gram dose of Cr₂0₃ as Cr₂0₃-Cellulose in two steers showed appreciable Cr₂0₃ in the feces within ten hours, a peak from approximately 18-26 hours in the better steer and levels near the limit of analytical accuracy from three to five days. The hypothesis, that poorer growth observed from forced feeding of common salt late in the grazing season was due to depressed forage intake, was rejected, using Lancaster's fecal nitrogen method for determining digestibility and once-daily Cr₂0₃ dosing and sampling with corrections obtained from Experiment 2 for fecal output to measure forage intake. Grab sample Cr₂0₃ concentration was significantly higher in the morning sample than the afternoon in all experiments. Coefficients of variation were higher in the morning for once daily dosing and higher in the afternoon in twice daily dosing. A series of 12 animal experiments and two simplified laboratory experiments were used to determine whether small nylon or cellulose acetate bags placed in the rumen could be passed through the alimentary tract and used as a possible method of measuring over-all forage digestibility. Bags tied to the fistula bung by nylon line were recovered intact at ten days. Rumen evacuation in cattle showed that nearly all bags placed free in the rumen had disappeared by three days with evidence of regurgitation on three occasions and only two free, intact bags. Sheep experiments by dosing and direct surgical placement in the rumen confirmed that regurgitation occurred. In a final slaughter experiment colored polyethylene and glass beads showed most, if not all, bags had been broken before reaching the reticulo-omasal orifice. All experimental observations on the fate of the bags are consistent with the following explanation. The bags in the rumen are subject to regurgitation; they cannot leave the rumen until this happens, following which the fragments are swallowed and are of a specific gravity and size that ensures their passage through the reticulo-omasal orifice. However, they are then dissolved in the acid environment of the lower stomachs. Although the problems of using the bag technique appear insurmountable, the manner of bag movements is believed to be fully understood.
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Forest disturbances, such as wildfires, pine beetle outbreaks, and floods are important features of many landscapes and ecosystems. Many disturbances are increasing in size, frequency, and intensity due ...
Citation Citation
- Title:
- Understanding Public Perceptions of Post-Wildfire Landscape Recovery
- Author:
- Kooistra, Chad
Forest disturbances, such as wildfires, pine beetle outbreaks, and floods are important features of many landscapes and ecosystems. Many disturbances are increasing in size, frequency, and intensity due to changing climates and land management decisions. The changing ecological and aesthetic conditions following a disturbance can lead to negative short- and long-term social impacts. This dissertation research examines one aspect of the relationship between people and their environment in the context of forest disturbances and landscape changes. Specifically, it explores how people perceive a changing landscape after a forest disturbance, a trajectory referred to here as landscape recovery. After describing the larger context of forest disturbances in the introductory chapter, with a focus on wildfires, my second dissertation chapter developed a conceptual framework for understanding how people perceive post-disturbance landscape recovery. It examined the social factors that are most likely to influence those perceptions based on literature from various disciplines. These factors included visual cues and aesthetic preferences, landscape values and connections, and beliefs about the ecological role of disturbances. I described how the concepts and methodological approaches from mental models and social representations traditions help depict and explain how perceptions of landscape recovery can be studied in a way that explores the process shaping the perceptions. I explained how these perceptions likely exist along a spectrum from more simple perceptions focused on aesthetic judgments to more complex perceptions based more on ecological knowledge. I then proposed a research agenda to further investigate this framework, along with a summary of management considerations. The third chapter empirically explored the framework from the previous chapter by applying social representations theory (SRT) to qualitative research in Montana about how people perceive post-wildfire landscape recovery. I examined the mechanistic (i.e., anchoring and objectification) and structural (i.e., central core and peripheral elements) aspects of representations by integrating the factors proposed earlier as most influential in affecting perceptions of recovery. Interviews were conducted in 2014 with 30 residents who experienced the 2012 Dahl Fire, near Roundup, MT. Participants were purposively selected to represent a range of the factors described in Chapter 2. The main propositions from Chapter 2 were explored in the data collection and analysis steps. The core of all respondents' representations was centered on the concept of "Mother Nature." The factors identified in Chapter 2 further shaped representations uniquely across the two main groups of residents (rural lifestyle and working landscape residents) through the anchoring and objectification processes. People's representations about recovery were anchored in general beliefs about the past ecological and socio-cultural role of fire in the landscape as influenced by their past experiences and knowledge about ecological disturbances. Interpretations of different aspects of the landscape, including vegetation composition and key ecosystem functions, were filtered through people's values for the landscape and their specific beliefs about how the fire affected the landscape. This led to variation in specific notions of what constitutes a recovered landscape across the two main social groups there. These findings are discussed in the context of SRT and post-wildfire management. My fourth chapter took a broader look at the variables that influence perceptions of landscape recovery across different wildfires. Twenty-five fires that occurred in 2011 or 2012 in WA, OR, MT, and ID were selected to represent a range of fire behavior characteristics and landscape impacts. Then, residents who live near each of the 25 fires were randomly selected to receive survey questionnaires which asked about multiple facets of their experiences with the fire, the perceived social impacts from the fire, and specifically how the landscape had changed/recovered since the fire. Results showed that, overall, perceptions of landscape recovery no more than two years after the fire were positive. Regression analysis suggested that perceptions of recovery can be explained fairly well with several key variables. More negative evaluations of recovery were related to negative impacts to people's attachment to the landscape, negative perceptions of erosion problems, and longer lasting fires. More positive evaluations of recovery were related to more positive beliefs about the beneficial role of fire in terms of landscape health. Hierarchical Linear Modelling (HLM) analysis showed that these relationships were mostly consistent across fires, though there was some variability in the relationships between perceptions of landscape recovery and the variables that measured perceptions of erosion and beliefs about the ecological role of fire. These findings are discussed in terms of the scope of the study as well as their management implications. My fifth and concluding chapter summarized the main findings from each chapter and integrated them into a larger social-ecological context. Key limitations, considerations related to the validity and reliability of my research, and future research needs are discussed. My dissertation furthers the conceptual and empirical understanding of how people perceive landscape changes from natural disturbances and how managers can include these social dimensions into future planning and implementation efforts.
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378. [Article] Interactive Genetic Algorithms for watershed planning : an investigation of usability and human-centered design
Degradation of watersheds is a major concern in areas where adverse climate effects and unsustainable use of the natural resources have caused extensive stresses to watershed systems (e.g., increased floods, ...Citation Citation
- Title:
- Interactive Genetic Algorithms for watershed planning : an investigation of usability and human-centered design
- Author:
- Piemonti, Adriana Debora
Degradation of watersheds is a major concern in areas where adverse climate effects and unsustainable use of the natural resources have caused extensive stresses to watershed systems (e.g., increased floods, increased droughts, worsened in-stream water quality) through the years. While considerable efforts are being made to generate technical solutions that focus on plans of spatially-distributed conservation practices (e.g., Wetlands, Filter Strips, Grassed Waterways, Crop Management practices, etc.) for restoration of existing conditions in the watersheds, adoption and implementation of these solutions require a better understanding of constraints faced by affected stakeholders and decision makers. Participatory modeling and design approaches have, as a result, become popular in the recent past to support a community's engagement during the modeling process and during development of potential scenarios of plans (or, design alternatives). And now, with new and ongoing developments in Web 2.0 technologies, there is an even greater need for research that examines how large number of stakeholders can be engaged in the development of design alternatives via the internet-based, decision support environments. The overarching goal of this research is to investigate how stakeholder participation ("humans") and Interactive Genetic Algorithms ("computer") can be coupled in a web-based watershed decision support system (DSS) called WRESTORE (Watershed REstoration using Spatio Temporal Optimization of REsources- http://wrestore.iupui.edu/), in order to generate user-preferred design alternatives of distributed conservation practices on a watershed landscape. An important component of this goal is to also improve the understanding of how human behavior on the graphical user interface (GUI) of the DSS can be observed and evaluated in real-time, and then learned from to further improve the performance of the underlying search algorithm. Four specific objectives were addressed in this work to accomplish the overall goal: • Objective 1: Observe interactions of multiple users with the GUI of a web-based watershed DSS (WRESTORE, http://wrestore.iupui.edu/) during interactive search experiments, and then use Usability metrics (response times, clicking events and confidence levels) to evaluate the differences and similarities in user behaviors and interactions. • Objective 2: Examine relationships between the type of users (e.g., stakeholders versus surrogates), the Usability metrics, and patterns in the watershed-scale plans of conservation practices generated by the multi-objective Interactive Genetic Algorithm embedded in WRESTORE. • Objective 3: Examine relationships between the type of users, the Usability metrics, and patterns in the user-preferred, sub-basin-scale plans of conservation practices generated by the multi-objective Interactive Genetic Algorithm embedded in WRESTORE. • Objective 4: Develop and test novel human-guided search operators that adaptively learn for patterns in user-preferred alternatives generated by the multi-objective Interactive Genetic Algorithm, and, as a result, improve the convergence rate of the search algorithm for generating design alternatives that conserve these learned patterns. Results show that there is a clear difference on how different types of users interact with the Interactive Optimization system. The observed relationship between confidence levels, time spent on a task, and number of mouse clicking events, indicated that participants who were able to use the WRESTORE GUI to gather more information and had a higher rate of time per number of clicks, tended to increase their levels of self-confidence in their own feedback. Also, when engaging with watershed stakeholders versus non-stakeholders (or, surrogates), 67% of the stakeholder participants steadily increased their average self-confidence levels as they continued to interact with the tool, in contrast to only 29% of surrogate participants who also showed an increase in their self-confidence levels through time. Such usability and confidence level evaluations provide assessments on which participant was potentially generating reliable feedback data for the search algorithm to use. An analysis of design alternatives generated by the individuals in both stakeholder and non-stakeholder groups showed that a majority (67%) of the stakeholder participants found a higher percentage (on and average 52%) of preferred design alternatives via the interactive search process. Also, users who were focused on assessing the suitability of design alternatives for the entire watershed trended to demonstrate a bias for one of the watershed-scale objective functions. In contrast, users, who were focused on assessing the suitability of design alternatives at only a few local sub-basins in the watershed, did not demonstrate any clear bias for any one of the watershed-scale objective functions. Additionally, patterns were observed in the design of decision alternatives generated by the human-centered search process, which further divulged potential user preferences related to the decision space for example, whether a specific participant preferred a certain practice over another, or a certain location over another for a specific practice. Finally, to improve the convergence rates of the Interactive Genetic Algorithm in WRESTORE, we investigated whether observed patterns in decisions (especially, when users were focused on local sub-regions of the watershed) can be used to improve the search for user-desire designs. A novel Interactive Genetic Algorithm with adaptive, human-guided, selection, crossover and mutation operators was proposed. The new algorithm was tested with six types of simulated participants (three deterministic and three probabilistic users) developed from the feedback data of three real participants. Results of search experiments with the novel adaptive IGA operators indicated a faster convergence than the default IGA, for two out of three deterministic simulated users. However, none of the probabilistic user showed a convergence different than the default values. This indicates that while current results indicate promise, there is need for additional research on adaptive, human-guided IGA operators, especially when noisy/stochastic users participate in the search. Additionally, adaptation of search operators have the potential to improve convergence rates when participatory design is done via Interactive Genetic Algorithms.
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This fifth annual Cooperative Pole Research Program report outlines our progress in the six project objectives. Improved Fumigants Sampling of previously established field tests revealed that Vorlex and ...
Citation Citation
- Title:
- Conserving energy by safe and environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1985
- Author:
- Oregon State University, Oregon State University. Dept. of Forest Products
This fifth annual Cooperative Pole Research Program report outlines our progress in the six project objectives. Improved Fumigants Sampling of previously established field tests revealed that Vorlex and Chloropicrin continued to perform well after 15 years, while Vapam was slightly less effective. Solid methylisothiocyanate (MIT) also performed well in the field after 7 years. In additional tests, gelatin encapsulated MIT migrated through Douglas-fir heartwood with addition of moderate quantities of water to degrade the gelatin. However, in the presence of higher quantities of water or no additional water, MIT migration into the wood was slowed. In a previously established test, gelatin encapsulated MIT continues to inhibit reinfestation of poles 3 years after treatment. Pelletized MIT is a new formulation (65% active ingredient) that appears to have some promise. Preliminary tests indicate that up to 95% of the MIT is release in 24 hours, but a small quantity of MIT remains in the pellets after 63 days aeration and may pose a disposal hazard. The solid MIT formulations will permit aboveground applications, increasing the risk that MIT will come in contact with pole hardware. Preliminary tests indicate that MIT had little effect on corrosion of hot dipped, galvanized bolts attached to wood. This suggests that treatment in the crossarm zone with MIT or fumigants that produce MIT should not affect the integrity of attached hardware. i-i In addition to fumigant evaluations, we recently examined an earlier test of groundline treatments with Osmoplastic® and Hollowheart®. After 10 years, these treatments are performing reasonably well, with only a slight rise in the incidence of decay fungi in the past 4 years. We also reevaluated the effectiveness of kerfing for preventing decay and found that this process reduced the depth and width of checks, resulting in a decreased incidence of decay fungi. Kerfing appears to be a valuable method for preventing internal decay at the groundline. Cedar Sapwood Decay Control This past year, the second set of five chemicals applied to control sapwood decay were evaluated after 2 years of exposure. As in earlier evaluations using the Aspergillus bioassay, none of the chemicals approach pentachlorophenol in oil for ability to inhibit sporulation of Aspergillus niger; however, several samples from zones deep in the wood produced a slight zone of effect. This may indicate the presence of a reservoir for long-term protection against decay. Several of the chemicals including Fluor Chrome Arsenic Phenol and Ammoniacal Copper Arsenate (ACA) appear to bind to the wood and may be difficult to detect by the bioassay method. We expect to assess the effectiveness of these treatments using a soil block test. Investigations of the reliability of the Aspergillus bioassay under a variety of conditions indicated that quantity of spores, use of glass or plastic petri dishes, long-term cold storage, and the use of spray inoculum instead of flooding spores had little influence on the bioassay results with pentachiorophenol, Tributyl-tinoxide, or 3 iodo propynyl butylcarbamate; however, incubation temperature did influence assay results. The Aspergillus bioassay is a simple, effective means for estimating residual preservative levels. Bolt Holes Again this year, wood around the unprotected, control bolt holes in pole sections contained such low levels of decay fungi that evaluation of the treated poles will be delayed another year. In addition to the initial bolt hole treatments, we have begun a test to determine if gelatin encapsulated or pelletized MIT can prevent decay development in field-drilled bolt holes. The pole sections used in these tests had already begun to develop decay prior to treatment and will provide an ideal test material. Detecting Decay and Estimatin& Residual Strength of Poles Fluorescent labeled lectins used in our earlier studies detected decay fungi at low weight losses under laboratory conditions. We are currently evaluating this method for detecting fungi in increment cores removed from poles to reduce the need for culturing. Last year we identified a peak that was unique to infrared (IR) spectra of warm water extracts from decayed wood. This past year we attempted to identify the chemical responsible for this peak and found that carbonyl compounds, probably from oxidative lignin degradation, were responsible for the peak. Since brown rot fungi apparently do iv not completely metabolize lignin breakdown products, they accumulate in the decaying wood and can be readily detected by their IR spectra. Strength properties of beams cut front Douglas-fir pole sections, air-seasoned for 3 years significantly decreased although decay fungi could not be uniformly isolated from the beams. In addition, there were gradual declines in work to maximum load and modulus of elasticity, as well as increased Pilodyn pin penetration. These results suggest that some strength losses occurred during air-seasoning; however, the losses were not large and should not endanger pole users. We compared several test methods including the Pilodyn, radial compression tests, longitudinal compression tests, and the pick test for evaluating residual pole strength of the wood surface of Douglas-fir treated with combinations of funtigants or groundline wraps. The results indicate that only the pick test could accurately detect surface damage and illustrate the difficulty of detecting surface damage. This past year we evaluated several sections cut from ACA treated poles stored for a number of years to determine if they were worth salvaging. Static bending tests of beams cut from the ACA treated zone, the treated/untreated boundary, and the inner heartwood revealed ACA treated sapwood had lower MOR and longitudinal compression strength than the other zones. These results represent only a small sample, but they suggest that some strength loss occurs during ACA V treatments. More importantly, the results suggest that we could have reliably predicted beam MOR by testing small plugs removed from the poles. Small beams cut from decaying, pentachlorophenol treated Douglas-fir poles were acoustically tested for residual wood strength, then evaluated to failure in static bending. The acoustic test consisted of sending a pulsed sonic wave into the wood and recording this wave after it passed through the beam. As it moved, the wave was altered by the presence of any wood defects or decay, and these alterations create a "fingerprint" specific for that defect. Preliminary results indicated that signal analysis was highly 2 2 correlated with work to maximum load (r =.82) and MOR (r .88), suggesting that this approach to decay detection may prove more reliable than measuring of sound velocity. Initiation of Decay in Air-Seasoning Douglas-fir The results of the initial survey to determine the incidence of decay fungi in poles from widely scattered Pacific Northwest seasoning yards indicated that a variety of fungi were colonizing the wood. While most of these fungi do not pose a serious decay problem, two species, Poria carbonica and Poria placenta, became increasingly abundant with length of air-seasoning. These fungi are also the most conunon decayers of Douglas-fir poles in service. As expected, the number of fungi and the wood volume they occupied increased with seasoning time; however, this incidence varied considerably between yards, especially in poles air-seasoned for vi shorter time periods. In addition to the variation between sites, many of the decay fungi colonizing the wood appear to be monokaryons, indicating that spores landing on the wood are initiating the infestation. The distribution of fungi within the poles indicated that several of the more abundant decay fungi were present in the outer sapwood where they would be eliminated by conventional pressure treatment. The remaining fungi were most abundant in the heartwood but were more concentrated near the pole end. This suggests that exposed end grain was more readily invaded than lateral grain exposed in checks. In addition to identifying the fungi colonizing Douglas-fir, we examined the effects these fungi had on wood strength. Toughness tests indicated the presence of wide variation in decay capability of the isolates. Although there was no consistent pattern, most of the isolates did not cause substantial decay and, of those that did, only . carbonica and P. placenta were sufficiently abundant to have a large influence on wood strength. Due to the prevalence of P. carbonica and P. placenta in the inner heartwood, where they might not be eliminated in a short heating cycle, we evaluated the temperature tolerance of these two fungi in Douglas-fir heartwood blocks. These tests indicated that both fungi were eliminated by exposure to temperatures above 71°C for over 1 hour or 60°C for 2 hours. The results suggest that careful control of temperature during treatment should eliminate decay fungi and that wood treated at ambient temperatures should be heated to kill fungi that become established during air-seasoning. vii This past year was the third and final year of the decay development study. In this study, sterile pole sections have been exposed for 1, 2, or 3 years at widely scattered Pacific Northwest sites, then returned to the laboratory and extensively sampled. We are now in the process of identifying the fungi from the third year poles. In addition to examining poles prior to preservative treatment, we are also evaluating poles treated with waterborne chemicals (ACA or CCA) for the incidence of surface decay. This past year we examined twenty ACA-treated poles from a line installed in 1946. While a variety of fungi were cultured from the wood, none of the poles had evidence of substantial surface deterioration. A study was initiated on the fungal flora of fumigant treated wood because of the potential for fungi developing resistance to low levels of fumigant or the ability to actively degrade the chemical. Both of these developments could shorten fumigant retreatment cycles and increase maintenance costs. We have evaluated poles treated 7 and 15 years ago with fumigants and find markedly reduced fungal flora. Tests are continuing on the fungi isolated, and we hope to assess the effects of these isolates on long-term fumigant effectiveness.