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1.
    
  1. Pitfall trapping is among the most widely used sampling methods for ground-dwelling beetles. However, the sampled ground-dwelling beetle abundance in pitfall traps may be biased, which can lead to difficulties when comparing the sampled abundance between different habitats.
  2. To better understand the comparability of the sampled abundance, we focused on two sampling processes: a temporary migration process (referring to the individual movements into and out of the effective trap area) and a removal process (determining the number of individuals collected given the number of individuals within the trap area).
  3. To examine the effects of the temporary migration process, we compared the sampled abundance of 10 ground-dwelling beetle species inside and outside enclosures in 2 habitats (clear-cut and forested sites) and found that installing the enclosure decreased the sampled abundance in both habitats, but the effects did not differ among habitats.
  4. To examine the effects of the removal process, we examined the effects of daily soil temperature on the daily sampled abundance (removal probability) of Pterostichus thunbergi using removal sampling within enclosures. We found that soil temperature increased the removal probability, but this effect was limited and not consistent across survey periods.
  5. The results suggest that the effects of the temporary migration process may not be habitat dependent and that the effects of the removal process may be small. Therefore, the traditional use of pitfall traps is, to some extent, a robust and comparable measure of the sampled abundance of ground-dwelling beetles among different habitats.
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2.
    
ABSTRACT American Crows (Corvus brachyrhynchos) are difficult to capture. I used a simple technique (box traps) to capture 151 crows incidental to my eastern coyote (Canis latrans) research at two study sites in eastern Massachusetts. Crows were captured at a higher rate during the spring (winter = 33 captures, spring = 70, summer = 22, and fall = 26). Among months, capture efficiency ranged from 0.7% in August to 8.5% in May, with an overall average of 4.1 crows captured per 100 trap days. Although other capture methods (e.g., net launchers and Australian crow traps) have been used to capture crows in greater numbers, box traps can be an important complement to the other capture techniques because they are transportable, easy to use, relatively cheap, and easy to obtain.  相似文献   

3.
    
Abstract: Minimizing and understanding the causes of capture-related injury should be a goal of every project that catches animals. We investigated the influence of age, weight, and sex on the field-assessed foot injury of 96 wolves (Canis lupus) captured in rubber-padded foothold traps. We then compared our results with those of 6 other types of wolf traps as reported in the literature. Injury from rubber-padded traps was lower than that of other traps, and age, weight, or sex did not influence foot damage. Rubber-padded foothold traps appear to be humane, and managers should consider their use for live capture of wolves.  相似文献   

4.
  总被引:2,自引:0,他引:2  
Daily samples between 1964 and 1991 from suction traps throughout Great Britain were used to study the migration phenologies of five aphid species: Brachycaudus helichrysi, Elatobium abietinum, Metopolophium dirhodum, Myzus persicae and Sitobion avenae, and their relationship with temperature. Regression relationships have been established between characteristics of aphid phenology and temperature, latitude and longitude for each species. There were differences between species in the period for which temperature was most strongly associated with aphid phenology. The study indicates that temperature, especially winter temperature, is the dominant factor affecting aphid phenology, for all five species. A 1 °C increase in average winter temperature advanced the migration phenology by 4–19 days depending on species. Effects of temperature on the aphid phenology are similar between holocyclic and anholocyclic species, unlike the effects of temperature on date of first flight record which have been previously shown to be important only in anholocyclic species.  相似文献   

5.
    
Population dynamic models combine density dependence and environmental effects. Ignoring sampling uncertainty might lead to biased estimation of the strength of density dependence. This is typically addressed using state‐space model approaches, which integrate sampling error and population process estimates. Such models seldom include an explicit link between the sampling procedures and the true abundance, which is common in capture–recapture settings. However, many of the models proposed to estimate abundance in the presence of capture heterogeneity lead to incomplete likelihood functions and cannot be straightforwardly included in state‐space models. We assessed the importance of estimating sampling error explicitly by taking an intermediate approach between ignoring uncertainty in abundance estimates and fully specified state‐space models for density‐dependence estimation based on autoregressive processes. First, we estimated individual capture probabilities based on a heterogeneity model for a closed population, using a conditional multinomial likelihood, followed by a Horvitz–Thompson estimate for abundance. Second, we estimated coefficients of autoregressive models for the log abundance. Inference was performed using the methodology of integrated nested Laplace approximation (INLA). We performed an extensive simulation study to compare our approach with estimates disregarding capture history information, and using R‐package VGAM, for different parameter specifications. The methods were then applied to a real data set of gray‐sided voles Myodes rufocanus from Northern Norway. We found that density‐dependence estimation was improved when explicitly modeling sampling error in scenarios with low process variances, in which differences in coverage reached up to 8% in estimating the coefficients of the autoregressive processes. In this case, the bias also increased assuming a Poisson distribution in the observational model. For high process variances, the differences between methods were small and it appeared less important to model heterogeneity.  相似文献   

6.
    
ANDREW J. TYRE7 ABSTRACT Despite the common use of Clover traps to capture white-tailed deer (Odocoileus virginianus), little published information exists quantifying trap success, trap selectivity (sex-age selection), or weather correlates of trap success. We quantified these relationships using white-tailed deer data from 3 study sites in the Lower Peninsula of Michigan, USA, during winters 2001–2007. We captured 610 deer in 8,569 trap-nights; pooled capture success was 0.07 deer/trap-night, although site-year success varied from 0.021 to 0.086. We compared sex-age classes (fawn [pooled by sex], ad M, ad F) captured with sex-age classes estimated to be available on each study site during each capture season. We used generalized linear mixed modeling to construct 19 a priori models to describe probability of capture success as a function of weather covariates (daily min. temp [° C], daily snowfall [cm], daily snow depth [cm]), Julian day, site, and year. General selection patterns included fawns captured more than expected and adult males captured less than expected; adult females were generally neutrally selected. The quasi-Akaike's Information Criterion best model within our set was described by the global model without Julian day and contained all 3 weather covariates and site-year effects. Our model provided some evidence that as daily snow depth increased, probability of capture increased; the positive effect of daily snowfall on capture probability was dependent on decreasing daily minimum temperature. Our results may be used to increase efficacy of deer capture programs by researchers and managers through informed decision-making about when to allocate effort (e.g., if extreme winter weather conditions are predicted) and when to consider alternative methods (e.g., if capture of ad M is an objective).  相似文献   

7.
    
ABSTRACT Several techniques have been used to capture Common Loons (Gavia immer), but effectiveness is limited during periods of the breeding season when loons do not have chicks. From 2005 to 2008, we studied loons in northern Wisconsin and used night lighting to capture loons on nests and also designed a lift net for capturing loons prior to nesting. At night, incubating loons were approached by boat and, when within about 30–60 m, we focused a spotlight on the loon and, once at the nest, captured loons using a landing net. Using this technique, we captured 23 loons in 29 attempts (79%). In addition, taped calls and loon decoys were used to entice prenesting, territorial loons into a shoreline‐based, lift‐net trap at a capture efficiency of 67% (10 captures in 15 attempts) during the second year of use. Our diurnal lift‐net trap and night‐light nest‐capture techniques allowed us to capture adult Common Loons during periods of the breeding season when previous investigators have found loons difficult to catch. These techniques may also be useful for capturing other species of territorial waterbirds, especially other species of loons.  相似文献   

8.
  总被引:1,自引:0,他引:1  
ABSTRACT.   The success of ornithological studies often hinges on a researcher's ability to capture individuals quickly and efficiently. Sometimes it is necessary to capture the same individual multiple times, as is the case in many metabolic, ecotoxicological, and immunocompetence studies. Several methods of capturing cavity-nesting birds at their nest boxes have been described. However, these methods proved inefficient when attempting to catch wary individuals that had already been captured previously. Here we describe a simple and inexpensive method for capturing cavity-nesting birds using a square plate of sheet metal (5.8 × 5.8 × 0.2 cm), a drinking straw, a piece of duct tape, and a monofilament line. This method has the advantages of allowing selective capture of one, but not both members of a pair and being nearly invisible to trap-shy birds.  相似文献   

9.
Testing capture homogeneity in a recapture model   总被引:1,自引:0,他引:1  
LLOYD  CHRIS J. 《Biometrika》1992,79(3):555-561
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10.
Due to their versatility, quadrupole ion traps have become popular mass spectrometers in the growing field of proteomics. High sensitivity, user friendliness and low cost are the key features that have contributed to the success of the technology. However, mass measurement accuracy, resolution and mass range are still not comparable to the analytical performances obtained on other mass spectrometers. In the past 5 years, researchers have tried to overcome these drawbacks, focusing their attention on two different aspects of ion-trap mass spectrometry, development of novel types of ion traps and manipulation of the gas-phase ion chemistry, in order to obtain alternative techniques for tandem mass spectrometry analysis. In the field of trapping devices, improvements in instrumental design have led to the linear ion trap, digital ion trap and orbitrap. Activation methods based on electrons, chemically produced by an anion or from irradiation with an electron beam, have demonstrated their utility in providing complementary sequence information for improving confidence in protein identification.  相似文献   

11.
  总被引:5,自引:2,他引:5  
The temperature dependence of the photosynthetic parameters Vcmax, the maximum catalytic rate of the enzyme Rubisco, and Jmax, the maximum electron transport rate, were examined using published datasets. An Arrehenius equation, modified to account for decreases in each parameter at high temperatures, satisfactorily described the temperature response for both parameters. There was remarkable conformity in Vcmax and Jmax between all plants at Tleaf < 25 °C, when each parameter was normalized by their respective values at 25 °C (Vcmax0 and Jmax0), but showed a high degree of variability between and within species at Tleaf > 30 °C. For both normalized Vcmax and Jmax, the maximum fractional error introduced by assuming a common temperature response function is < ± 0·1 for most plants and < ± 0·22 for all plants when Tleaf < 25 °C. Fractional errors are typically < ± 0·45 in the temperature range 25–30 °C, but very large errors occur when a common function is used to estimate the photosynthetic parameters at temperatures > 30 °C. The ratio Jmax/Vcmax varies with temperature, but analysis of the ratio at Tleaf = 25 °C using the fitted mean temperature response functions results in Jmax0/Vcmax0 = 2·00 ± 0·60 (SD, n = 43).  相似文献   

12.
    
Removal of biologically available nitrogen (N) by the microbially mediated processes denitrification and anaerobic ammonium oxidation (anammox) affects ecosystem N availability. Although few studies have examined temperature responses of denitrification and anammox, previous work suggests that denitrification could become more important than anammox in response to climate warming. To test this hypothesis, we determined whether temperature responses of denitrification and anammox differed in shelf and estuarine sediments from coastal Rhode Island over a seasonal cycle. The influence of temperature and organic C availability was further assessed in a 12‐week laboratory microcosm experiment. Temperature responses, as characterized by thermal optima (Topt) and apparent activation energy (Ea), were determined by measuring potential rates of denitrification and anammox at 31 discrete temperatures ranging from 3 to 59 °C. With a few exceptions, Topt and Ea of denitrification and anammox did not differ in Rhode Island sediments over the seasonal cycle. In microcosm sediments, Ea was somewhat lower for anammox compared to denitrification across all treatments. However, Topt did not differ between processes, and neither Ea nor Topt changed with warming or carbon addition. Thus, the two processes behaved similarly in terms of temperature responses, and these responses were not influenced by warming. This led us to reject the hypothesis that anammox is more cold‐adapted than denitrification in our study system. Overall, our study suggests that temperature responses of both processes can be accurately modeled for temperate regions in the future using a single set of parameters, which are likely not to change over the next century as a result of predicted climate warming. We further conclude that climate warming will not directly alter the partitioning of N flow through anammox and denitrification.  相似文献   

13.
    
The present study aimed firstly, to test for a temperature effect on North Sea haddock Melanogrammus aeglefinus growth and secondly, to develop a model that could be used to assess total length (L(T)) and mass (M)-at-age response to different temperature scenarios. The von Bertalanffy growth model was fitted on a cohort-by-cohort basis from 1970 to 2006. The asymptotic L(T) (L(∞)) was negatively correlated with temperature while the rate at which L(∞) is reached (K) was positively correlated with temperature. K was negatively correlated with density, whereas no effect on L(∞) was observed. These effects were incorporated into a von Bertalanffy model which was extended to include temperature and density as explanatory variables. Only the temperature variable was significant. Fitting the extended von Bertalanffy model revealed that L(∞) decreased while K increased with increasing temperature, resulting in up to a 40% loss of individual yield at older ages. The dramatic decline observed in the mean age at which 50% of the population becomes mature suggests that higher temperatures resulted in larger young M. aeglefinus that matured earlier and therefore reached a smaller maximum size. In a global warming context, the loss of individual yield observed at old ages is likely to reduce the fisheries yield for M. aeglefinus in the North Sea.  相似文献   

14.
The magnitude and direction of phenological shifts from climate warming could be predictably variable across the planet depending upon the nature of physiological controls on phenology, the thermal sensitivity of the developmental processes and global patterns in the climate warming. We tested this with respect to the flight phenology of adult nocturnal moths (3.33 million captures of 334 species) that were sampled at sites in southern and northern Finland during 1993–2012 (with years 2005–2012 treated as an independent model validation data set). We compared eight competing models of physiological controls on flight phenology to each species and found strong support for thermal controls of phenology in 66% of the species generations. Among species with strong thermal control of phenology in both the south and north, the average development rate was higher in northern vs. southern populations at 10 °C, but about the same at 15 and 20 °C. With a 3 °C increase in temperature (approximating A2 scenario of IPPC for 2090–2099 relative to 1980–1999) these species were predicted to advance their phenology on average by 17 (SE ± 0.3) days in the south vs. 13 (±0.4) days in the north. The higher development rates at low temperatures of poleward populations makes them less sensitive to climate warming, which opposes the tendency for stronger phenological advances in the north from greater increases in temperature.  相似文献   

15.
    
  1. Temperature is probably the most important driver of insect response to climate change and has many implications at both individual and population levels. The present study explored how elevation, as a proxy for temperature, affects the abundance and diversity of bark and wood‐boring beetles associated with Norway spruce (Picea abies) along its southern range.
  2. We selected three elevational gradients (approximately 900–1500 m) in spruce stands in the south‐eastern Alps, each consisting of four locations. From April to September 2011, four traps of different types were installed at each location: three baited with generic lures (α‐pinene and ethanol) and one baited with a pheromone specific for Ips typographus. In addition, three fresh spruce logs were exposed on the same locations.
  3. Species richness did not vary significantly with elevation, whereas the abundance of most individual species did. Generally, aggressive species responded positively to higher temperature, whereas most non‐aggressive species responded negatively.
  4. In a warming scenario, it is likely that spruce forests will face increasing damage from aggressive species. This will threaten the growth and survival of Norway spruce at low elevation, especially at southern latitudes.
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16.
    
Subaquatic light traps are often used for sampling of the aquatic insects; however, their efficiency has not been tested yet. Here, we describe the use of such traps, illustrate the design of a simple trap allowing standardised sampling, and present results of assessment of the light trap efficiency according to the different turbidity levels, as well as model insects’ escape rates. The effect of turbidity on the capture efficiency was not significant for Sigara lateralis (Leach, 1817), Notonecta glauca Linnaeus, 1758 and Corixa punctata (Illiger, 1807) and was marginally significant for Chaoborus sp. Escape rates were affected by the entrance size and daylight exposure time. Although subaquatic light traps are helpful for standardised sampling, their entrance should be adequate for the target species, and the traps should be removed soon after the dawn or the resulting specimen counts should be corrected for the daylight exposure time before the trap removal.  相似文献   

17.
    
Monitoring procedures for Alpine ibex Capra ibex are limited in habitats with reduced visibility and when physical capture and marking of the animals is not intended. Photographic sampling, involving using camera‐trap data and identifying ibex from natural markings, was adopted with capture‐recapture models to estimate the abundance of ibex in Austria. The software CAPTURE's model produced an average capture probability of 0.44 with an estimate of 34–51 ibex and a mean population size of 38 ibex. This first study showed the applicability of photographic capture‐recapture techniques to estimate the abundance of ibex based on their natural markings.  相似文献   

18.
    
Toxigenic Dinophysis spp. are obligate mixotrophic dinoflagellates that require a constant supply of prey—Mesodinium rubrum—to achieve long-term growth by means of kleptoplasty. Mesodinium rubrum is, however, a fast moving, jumping ciliate exhibiting an effective escape response from suspensivorous predators. In the present study, a series of laboratory experiments evaluating the motility and survival of M. rubrum in the presence of Dinophysis cells and/or substances contained in their culture medium was designed, in order to assess the mechanisms involved in prey capture by Dinophysis spp. Cell abundance of M. rubrum decreased in the presence of Dinophysis cf. ovum cells producing okadaic acid (OA; up to 7.94 ± 2.67 pg cell−1) and smaller amounts of dinophysistoxin-1 (DTX-1) and pectenotoxin-2 (PTX-2). Prey capture was often observed after the ciliate had been attached to adhesive “mucus traps”, which only appeared in the presence of Dinophysis cells. Before being attached to the mucus traps, M. rubrum cells reduced significantly their swimming frequency (from ∼41 to 19 ± 3 jumps min−1) after only 4 h of initial contact with D. cf. ovum cells. M. rubrum survival was not affected in contact with purified OA, DTX-1 and PTX-2 solutions, but decreased significantly when the ciliate was exposed to cell-free or filtered culture medium from both D. cf. ovum and D. caudata, the latter containing moderate concentrations of free eicosapentaenoic acid and docosahexaenoic acid. The results thus indicate that Dinophysis combines the release of toxic compounds other than shellfish toxins, possibly free PUFAs, and a “mucus trap” to enhance its prey capture success by immobilizing and subsequently arresting M. rubrum cells.  相似文献   

19.
    
Single male sexually selected traits have been found to exhibit substantial genetic variance, even though natural and sexual selection are predicted to deplete genetic variance in these traits. We tested whether genetic variance in multiple male display traits of Drosophila serrata was maintained under field conditions. A breeding design involving 300 field-reared males and their laboratory-reared offspring allowed the estimation of the genetic variance-covariance matrix for six male cuticular hydrocarbons (CHCs) under field conditions. Despite individual CHCs displaying substantial genetic variance under field conditions, the vast majority of genetic variance in CHCs was not closely associated with the direction of sexual selection measured on field phenotypes. Relative concentrations of three CHCs correlated positively with body size in the field, but not under laboratory conditions, suggesting condition-dependent expression of CHCs under field conditions. Therefore condition dependence may not maintain genetic variance in preferred combinations of male CHCs under field conditions, suggesting that the large mutational target supplied by the evolution of condition dependence may not provide a solution to the lek paradox in this species. Sustained sexual selection may be adequate to deplete genetic variance in the direction of selection, perhaps as a consequence of the low rate of favorable mutations expected in multiple trait systems.  相似文献   

20.
    
1. A relationship between sampling efficiency and Taylor's power law (TPL) is derived and illustrated with data from gypsy moth samples taken in Pennsylvania. 2. It is shown that attractant traps such as pheromone and light traps may exhibit density‐dependent sampling efficiency which can influence the parameters of TPL. 3. Comparison of the light trap and pheromone trap sample data with those of a standardised suction trap enables the attractant traps to be standardised. 4. Rescaling male moth catches per trap to number per unit volume increases the slope, intercept and correlation coefficient while stretching the pattern of data points. 5. Density‐dependent sampling efficiency of attractant traps shows how TPL is sensitive to spatial aggregation behaviour as well as other life‐history variables.  相似文献   

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