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181.
Sublethal predation can be a significant trophic pathway in sediment communities, and the regeneration of damaged tissue affects
the activity, growth, and reproduction of prey. A field experiment was conducted 12–18 July 2010 in the Tijuana Estuary, California
(+32.56617°, −117.13152°), to measure in situ rates of body growth and palp regeneration of the polychaete Polydora cornuta after simulating sublethal predation by removing 2, 1, or 0 palps from labeled individuals. After 3 days in the field, individuals
that had 2 palps removed grew significantly slower than worms that had 0 palps removed; 1-palp worms had intermediate growth.
After 6 days in the field, rates of body growth were faster than those of worms recovered after 3 days, with similar trends
among the three palp treatments. During the 3-day transplantation, removed palps regenerated to half the initial length of
unmanipulated palps. After 6 days, palp lengths did not differ significantly among treatment groups, indicating complete regeneration.
The regeneration rate of removed palps was significantly faster than the growth rate of undamaged palps, and palp regeneration
rate did not differ significantly between worms that had 1 or 2 palps removed. 相似文献
182.
Adam F. A. Pellegrini Brian D. Wisenden Peter W. Sorensen 《Behavioral ecology and sociobiology》2010,64(3):381-387
A behavioral syndrome is a suite of behaviors correlated across multiple social contexts. In this study, boldness in the face
of predation risk was assessed twice in fish across two different sensory modalities in both the field and lab to ascertain
the biological relevance and complexity of this attribute. Individual fathead minnows were captured from a natural field population
using traps that either contained chemical alarm cues (conspecific skin extract) or control (well water) and their responses
to the presence of predator behind a glass partition assessed in the laboratory. Although fewer fish were captured in alarm
cue-labeled traps, these bold fish performed longer predator inspections than shy fish captured in control traps. Thus, a
shy/bold behavioral syndrome was expressed consistently across field and lab settings in response to both chemical and visual
indicators of danger. Shy and bold individuals did not differ in sex, body length, secondary sexual characteristics, or parasite
load but were of more robust physical condition. 相似文献
183.
Brian R. Johnson 《Behavioral ecology and sociobiology》2010,64(3):305-316
Honeybees exhibit two patterns of organization of work. In the spring and summer, division of labor is used to maximize growth
rate and resource accumulation, while during the winter, worker survivorship through the poor season is paramount, and bees
become generalists. This work proposes new organismal and proximate level conceptual models for these phenomena. The first
half of the paper presents a push–pull model for temporal polyethism. Members of the nursing caste are proposed to be pushed
from their caste by the development of workers behind them in the temporal caste sequence, while middle-aged bees are pulled
from their caste via interactions with the caste ahead of them. The model is, hence, an amalgamation of previous models, in
particular, the social inhibition and foraging for work models. The second half of the paper presents a model for the proximate
basis of temporal polyethism. Temporal castes exhibit specialized physiology and switch caste when it is adaptive at the colony
level. The model proposes that caste-specific physiology is dependent on mutually reinforcing positive feedback mechanisms
that lock a bee into a particular behavioral phase. Releasing mechanisms that relate colony level information are then hypothesized
to disrupt particular components of the priming mechanisms to trigger endocrinological cascades that lead to the next temporal
caste. Priming and releasing mechanisms for the nursing caste are mapped out that are consistent with current experimental
results. Less information-rich, but plausible, mechanisms for the middle-aged and foraging castes are also presented. 相似文献
184.
Brian F. Gore 《International journal of occupational safety and ergonomics》2013,19(3):339-351
Human Performance Modeling (HPM) is a computer-aided job analysis software methodology used to generate predictions of complex humanautomation integration and system flow patterns with the goal of improving operator and system safety. The use of HPM tools has recently been increasing due to reductions in computational cost, augmentations in the tool’s fidelity, and usefulness in the generated output. An examination of an Air Man-machine Integration Design and Analysis System (Air MIDAS) model evaluating complex human-automation integration currently underway at NASA Ames Research Center will highlight the importance to occupational safety of considering both cognitive and physical aspects of performance when researching human error. 相似文献
185.
Refaul Ferdous Faisal Khan Rehan Sadiq Paul Amyotte Brian Veitch 《Process Safety and Environmental Protection》2013,91(1-2):1-18
A bow-tie diagram combines a fault tree and an event tree to represent the risk control parameters on a common platform for mitigating an accident. Quantitative analysis of a bow-tie is still a major challenge since it follows the traditional assumptions of fault and event tree analyses. The assumptions consider the crisp probabilities and “independent” relationships for the input events. The crisp probabilities for the input events are often missing or hard to come by, which introduces data uncertainty. The assumption of “independence” introduces model uncertainty. Elicitation of expert's knowledge for the missing data may provide an alternative; however, such knowledge incorporates uncertainties and may undermine the credibility of risk analysis.This paper attempts to accommodate the expert's knowledge to overcome missing data and incorporate fuzzy set and evidence theory to assess the uncertainties. Further, dependency coefficient-based fuzzy and evidence theory approaches have been developed to address the model uncertainty for bow-tie analysis. In addition, a method of sensitivity analysis is proposed to predict the most contributing input events in the bow-tie analysis. To demonstrate the utility of the approaches in industrial application, a bow-tie diagram of the BP Texas City accident is developed and analyzed. 相似文献
186.
Using historical General Land Office record as a reference, this study employed a landscape-scale disturbance and succession model to estimate the future cumulative effects of six alternative management plans on the tree species composition for various physiographic settings for the Mark Twain National Forest in Missouri. The results indicate that over a 200-year horizon, the relative abundance of black oak and pine species groups will decrease and the relative abundance of the white oak species group will increase, regardless of management strategy. General Land Office witness tree records provide a measure of tree species composition in the period from 1800 to 1850, prior to the large-scale influx of European settlers. Compared to the tree species composition described in the General Land Office records, the six contemporary management alternatives considered all would lead to a lower abundance of pine species, a higher abundance of red/black oak species, and a slightly higher abundance of white oak species after 200 years. Impacts of management on tree species composition varied with physiographic settings. The projected relative abundance of pine differed significantly across the five physiographic classes over the first 40 years of the simulation. In the medium term (simulation years 41-100) the projected relative pine abundance differed significantly among only four physiographic classes. In the long term (simulation years 100-200) the projected relative pine abundance differed for only one physiographic class. In contrast, differences among physiographic classes in the relative abundance of black oaks and white oaks increased over time. In general, the expected long-term differences in relative tree species abundance among six proposed alternative management plans are small compared to shifts in tree species composition that have occurred from 1850 to the present. 相似文献
187.
Biodiversity goals are becoming increasingly important in stream restoration. Typical models of stream restoration are based
on the assumption that if habitat is restored then species will return and ecological processes will re-establish. However,
a range of constraints at different scales can affect restoration success. Much of the research in stream restoration ecology
has focused on habitat constraints, namely the in-stream and riparian conditions required to restore biota. Dispersal constraints
are also integral to determining the timescales, trajectory and potential endpoints of a restored ecosystem. Dispersal is
both a means of organism recolonization of restored sites and a vital ecological process that maintains viable populations.
We review knowledge of dispersal pathways and explore the factors influencing stream invertebrate dispersal. From empirical
and modeling studies of restoration in warm-temperate zones of New Zealand, we make predictions about the timescales of stream
ecological restoration under differing levels of dispersal constraints. This process of constraints identification and timescale
prediction is proposed as a practical step for resource managers to prioritize and appropriately monitor restoration sites
and highlights that in some instances, natural recolonization and achievement of biodiversity goals may not occur. 相似文献
188.
Evaluating China's Slope Land Conversion Program as sustainable management in Tianquan and Wuqi Counties 总被引:1,自引:0,他引:1
Increased soil erosion on sloped land has become a significant environmental concern in China that has been attributed to human activities such as deforestation, over-cultivation, and over-grazing of livestock. In order to reduce soil erosion on sloped lands, the Chinese government has responded by implementing large-scale, ecological rehabilitation programs, including the "Grain for Green" reforestation project. This program involves financial incentives to transition farmers into other economic activities with the goal of reducing ecological pressures and degradation. Because of the scope and potential impacts from these programs, detailed research is needed to understand their social and ecological effects. This paper reports on research conducted in Tianquan County, Sichuan Province, and Wuqi County, Shaanxi Province, that evaluates the effects of the program upon local economies and household livelihood systems. The paper argues that the successful conversion of farmland under "Grain for Green" depends upon local government involvement, local economic development, and funding for local projects. Without economic development within rural economies, we conclude that farmers will remain dependent upon continued subsidy assistance to meet the policy's ambitious environmental restrictions, thereby undermining the program's long-term sustainability. 相似文献
189.
Congruence Among Encounters,Norms, Crowding,and Management in a Marine Protected Area 总被引:1,自引:0,他引:1
Over the past few decades, recreation and tourism use has increased at many marine protected areas, generating concerns about
impacts of this increasing use on experiences and conditions at these areas (e.g., crowding, conflict). This article uses
data from Molokini Shoal Marine Life Conservation District in Hawai’i to examine: (a) reported encounters, crowding, normative
tolerances for various use levels, and support of use related management strategies at this site; and (b) whether users who
encounter higher use levels than their norms feel more crowded and are more supportive of restrictive management strategies.
Data were obtained from onsite pre-trip and post-trip questionnaires of 712 passengers on commercial snorkel and dive tours
visiting this site. Norms were measured with acceptance of 12 photographs depicting levels of boat use. On average, users
would accept seeing no more than approximately 16 boats at one time at Molokini and this number was observed on over 20% of
trips to the site. Although the majority of users expected to escape crowds at Molokini, 67% felt crowded and up to 79% supported
actions that would directly restrict use at this site (e.g., limit number of boats). Users who encountered more boats than
their normative tolerance felt more crowded and were more supportive of these management strategies. Findings suggest that
this marine protected area is operating over its capacity and management is needed to improve experiences and conditions. 相似文献
190.
Male fitness is often determined by the ability of the male to gain access to multiple mates, although in species that exhibit
sexual cannibalism, males might increase their likelihood of being cannibalized with each encounter. This risk should create
selection for males who are able to perceive potential risks associated with mating encounters. We studied male Schizocosa ocreata wolf spiders to determine whether they use female chemotactile cues (silk, excreta) as indicators of potential risks and
how these cues affected subsequent male courtship behaviors. Female treatments included satiated females vs. starved females,
as well as a treatment where females had recently cannibalized a male S. ocreata. We performed experiments to assess (1) if males use female chemotactile cues to determine potential risks associated with
differing female feeding treatments and alter courtship investment, and 2) how male experience with female chemotactile cues
affected courtship investment in subsequent female encounters. At first encounter, males do not vary courtship investment
(number of bouts, duration, and vigor) with different female feeding treatments. However, male behaviors during subsequent
encounters with female chemotactile cues varied in complex ways, depending on female feeding treatment and male first encounter
experience. These data suggest that male experience impacts perception of female chemical cues and offers the male opportunity
to avoid sexual cannibalism in high-risk situations. 相似文献