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651.
Plant traits are influenced by herbivore diet selection, but little is known about how traits are affected by different types of herbivores. We related eight traits of 27 subalpine shrub species in South Island, New Zealand, to damage of these shrubs by introduced red deer (Cervus elaphus) and native invertebrate herbivores using phylogenetically explicit modeling. Deer preferentially consumed species that grew quickly, were low in foliar tannins, or had high leaf area per unit mass. However, these traits did not trade off against each other; rather, they could be related to different multivariate defense strategies. Although the proportion of leaves damaged by leaf-chewing invertebrates also increased with stem growth, invertebrates did not damage the same fast growing species as those preferred by deer. Other traits may also be important in determining herbivore preferences, as suggested by the high proportion of variation in herbivory explained by phylogeny. Last, we found that the composition of invertebrate herbivore communities was more similar among closely related shrubs, and consequently, the range of invertebrate-plant associations may change if introduced deer shift plant composition toward slow-growing species. Overall, our results demonstrate the importance of herbivore type and coevolved interactions for the adaptive significance of plant traits. 相似文献
652.
Terrestrial, benthic, and pelagic resource use in lakes: results from a three-isotope Bayesian mixing model 总被引:2,自引:0,他引:2
Solomon CT Carpenter SR Clayton MK Cole JJ Coloso JJ Pace ML Zanden MJ Weidel BC 《Ecology》2011,92(5):1115-1125
Fluxes of organic matter across habitat boundaries are common in food webs. These fluxes may strongly influence community dynamics, depending on the extent to which they are used by consumers. Yet understanding of basal resource use by consumers is limited, because describing trophic pathways in complex food webs is difficult. We quantified resource use for zooplankton, zoobenthos, and fishes in four low-productivity lakes, using a Bayesian mixing model and measurements of hydrogen, carbon, and nitrogen stable isotope ratios. Multiple sources of uncertainty were explicitly incorporated into the model. As a result, posterior estimates of resource use were often broad distributions; nevertheless, clear patterns were evident. Zooplankton relied on terrestrial and pelagic primary production, while zoobenthos and fishes relied on terrestrial and benthic primary production. Across all consumer groups terrestrial reliance tended to be higher, and benthic reliance lower, in lakes where light penetration was low due to inputs of terrestrial dissolved organic carbon. These results support and refine an emerging consensus that terrestrial and benthic support of lake food webs can be substantial, and they imply that changes in the relative availability of basal resources drive the strength of cross-habitat trophic connections. 相似文献
653.
Lena von Harbou Corinna D. Dubischar Evgeny A. Pakhomov Brian P. V. Hunt Wilhelm Hagen Ulrich V. Bathmann 《Marine Biology》2011,158(9):2009-2026
Feeding dynamics of the Antarctic salps Ihlea racovitzai and Salpa thompsoni were studied in the Lazarev Sea in fall 2004, summer 2005–2006 and winter 2006. Pigment concentrations in the guts of both
species were positively correlated with ambient surface chlorophyll a (chl a). No evidence was found for salp clogging even at dense surface concentrations of up to 7 μg chl a L−1. However, gut pigment concentrations had a lower range than ambient pigment concentrations, suggesting that salps increased
retention times of ingested material in low-food environments. For medium-sized I. racovitzai and S. thompsoni, estimated individual daily rations reached 7–10 and >100% of body carbon in winter and summer, respectively. Daily respiratory
needs of I. racovitzai and S. thompsoni accounted for 28 and 22% of daily carbon assimilation based on pigment ingestion rates in winter, and for 2 and 1% in summer,
respectively. The grazing impact of the salp populations on the phytoplankton standing stock was negligible during all seasons
due to generally low salp densities. Fatty acid trophic biomarkers in the salps suggest high year-round contributions of flagellates
and modest contributions of diatoms to the salp’s diet. These markers showed low seasonal variability for I. racovitzai. The more pronounced seasonality of trophic markers in S. thompsoni were likely related to their generally deeper residence depth in winter linked to a seasonal alternation of sexual and asexual
generations. 相似文献
654.
Ecosystems are dynamic complexes. These dynamics can be described by different ecophysiological parameters and systems theoretical concepts like succession, thermodynamics, information/network theory, resilience, adaptability and the orientor concept. In this paper, different indicators and concepts are linked to Holling's adaptive cycle metaphor in order to derive hypotheses on potential system trajectories. The hypotheses focus on an exemplary temperate forest ecosystem experiencing the adaptive cycle's four phases of exploitation, conservation, collapse and reorganization after an initializing fire event. The different properties are correlated to the number of total system connections and show varying trajectories. Additionally, the provision of selected forest ecosystem services during the different phases is hypothesized and compared to three other land use types. 相似文献
655.
The National Research Council identified odors as a significant animal emission and highlighted the need to develop standardized protocols for sampling and analysis. The purpose of our study was to compare different odor sampling techniques for monitoring odors emitted from stored swine manure. In our study, odorous headspace air from swine manure holding tanks were analyzed by human panels and analytical techniques. Odorous air was analyzed by human panels using dynamic dilution olfactometry (DDO). Chemical analysis used acid traps for ammonia (NH?), fluorescence for hydrogen sulfide (H?S), and thermal desorption gas chromatography-mass spectrometry for volatile organic compounds (VOCs). Chemical analysis included the use of gas chromatography-olfactometry (GC-O) for determining key odorants. Chemical odorant concentrations were converted to odor activity values (OAVs) based on literature odor thresholds. The GC-O technique used was GC-SNIF. Dilution thresholds measured by different odor panels were significantly different by almost an order of magnitude even though the main odorous compound concentrations had not changed significantly. Only 5% of the key odorous VOCs total OAVs was recovered from the Tedlar bags used in DDO analysis. Ammonia was the only chemical odorant significantly correlated with DDO analysis in the fresh (1 wk) and aged manure. Chemical analysis showed that odor concentration stabilized after 5 to 7 wk and that HS was the most dominant odorant. In aged manure, neither volatile fatty acids (VFAs) nor HS was correlated with any other chemical odorant, but NH, phenols, and indoles were correlated, and phenols and indoles were highly correlated. Correlation of odorant concentration was closely associated with the origin of the odorant in the diet. Key odorants determined by chemical and GC-O included indoles, phenols, NH?, and several VFAs (butanoic, 3-methylbutanoic, and pentanoic acids). 相似文献
656.
Nestmate recognition in social insects: overcoming physiological constraints with collective decision making 总被引:1,自引:1,他引:0
Social insects rank among the most abundant and influential terrestrial organisms. The key to their success is their ability
to form tightly knit social groups that perform work cooperatively, and effectively exclude non-members from the colony. An
extensive body of research, both empirical and theoretical, has explored how optimal acceptance thresholds could evolve in
individuals, driven by the twin costs of inappropriately rejecting true nestmates and erroneously accepting individuals from
foreign colonies. Here, in contrast, we use agent-based modeling to show that strong nestmate recognition by individuals is
often unnecessary. Instead, highly effective nestmate recognition can arise as a colony-level property from a collective of
individually poor recognizers. Essentially, although an intruder can get by one defender when their odor cues are similar,
it is nearly impossible to get past many defenders if there is the slightest difference in cues. The results of our models
match observed rejection rates in studies of ants, wasps, and bees. We also show that previous research in support of the
optimal threshold theory approach to the problem of nestmate recognition can be alternatively viewed as evidence in favor
of the collective formation of a selectively permeable barrier that allows in nestmates (at a significant cost) while rejecting
non-nestmates. Finally, this work shows that nestmate recognition has a stronger task allocation component than previously
thought, as colonies can nearly always achieve perfect nestmate recognition if it is cost effective for them to do so at the
colony level. 相似文献
657.
Environmental Fluid Mechanics - We investigate the effects of anisotropic permeability and changing boundary conditions upon the onset of penetrative convection in a porous medium of Darcy type and... 相似文献
658.
Paudel Keshav R. Mehta Meenu Yin Geena Hew Suet Yen Lee Li Malyla Vamshikrishna Patel Vyoma K. Panneerselvam Jithendra Madheswaran Thiagarajan MacLoughlin Ronan Jha Niraj Kumar Gupta Piyush Kumar Singh Sachin Kumar Gupta Gaurav Kumar Pradeep Oliver Brian G. Hansbro Philip M. Chellappan Dinesh Kumar Dua Kamal 《Environmental science and pollution research international》2022,29(31):46830-46847
Environmental Science and Pollution Research - Non-small cell lung cancer (NSCLC) is reported to have a high incidence rate and is one of the most prevalent types of cancer contributing towards 85%... 相似文献
659.
Autoantibodies and autoimmune disorders in SARS-CoV-2 infection: pathogenicity and immune regulation
Darmarajan Thiviya Paudel Keshav Raj Candasamy Mayuren Chellian Jestin Madheswaran Thiagarajan Sakthivel Lakshmana Prabu Goh Bey Hing Gupta Piyush Kumar Jha Niraj Kumar Devkota Hari Prasad Gupta Gaurav Gulati Monica Singh Sachin Kumar Hansbro Philip Michael Oliver Brian Gregory George Dua Kamal Chellappan Dinesh Kumar 《Environmental science and pollution research international》2022,29(36):54072-54087
Environmental Science and Pollution Research - Coronavirus disease 2019 (COVID-19) is an infectious disease associated with the respiratory system caused by the SARS-CoV-2 virus. The aim of this... 相似文献
660.
The toxic equivalency (TEQ) values of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) are predicted with a model based on the homologue concentrations measured from a laboratory-scale reactor (124 data points), a package boiler (61 data points), and operating municipal waste incinerators (114 data points). Regardless of the three scales and types of equipment, the different temperature profiles, sampling emissions and/or solids (fly ash), and the various chemical and physical properties of the fuels, all the PCDF plots showed highly linear correlations (R(2)>0.99). The fitting lines of the reactor and the boiler data were almost linear with slope of unity, whereas the slope of the municipal waste incinerator data was 0.86, which is caused by higher predicted values for samples with high measured TEQ. The strong correlation also implies that each of the 10 toxic PCDF congeners has a constant concentration relative to its respective total homologue concentration despite a wide range of facility types and combustion conditions. The PCDD plots showed significant scatter and poor linearity, which implies that the relative concentration of PCDD TEQ congeners is more sensitive to variations in reaction conditions than that of the PCDF congeners. 相似文献