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31.
Understanding the rules and factors that drive the foraging behavior of large herbivores is important to describe their interaction with the landscape at various spatial scales. Some unresolved questions refer to landscape-behavioral interactions that result in oriented or random search in seasonally changing landscapes. Remotely sensed position data indicate that herbivores select local patches of heterogeneous landscapes depending on a complex host of dynamically varying animal and environmental conditions. Since foraging paths consist in successions of relatively short steps, increasing the frequency at which position information is acquired would contribute to entangle the mechanisms resulting in herbivores’ foraging paths. We addressed the question whether herbivores would obtain information at a patch scale that would modify their distribution at a landscape scale based on directed movement or navigation ability. We considered a set of 100,000 high-frequency (1 min intervals) position data of several free-ranging sheep (Ovis aries) at a seasonal-varying range (Patagonian Monte, Argentina) and observed their movements at landscape and at single vegetation patch scales. At a landscape scale, we inspected the spatial co-variation of seasonally varying forage offer and ewes’ movement speeds. At a patch scale, we developed a phase-state (P-S) model of movement cycles based on the occurrence of behavioral phases along foraging paths, and fitted it to the observed daily time series of ewes’ movement speeds. Ewes were preferentially distributed in areas with high forage offer during periods of low forage availability and the reverse occurred during the season of high forage availability. Parameters of the model of activity cycles amenable to control by ewes (duration of speed phases, time elapsed between speed cycles) did not covariate with forage offer, but varied significantly among ewes. The shape (kurtosis) parameter of the model of movement cycles, one which is unlikely under ewes’ control, co-varied significantly with spatial forage offer but did not differ among ewes. We conclude that ewes allocated foraging time along a series of similar movement efforts irrespective of forage availability at small patches. Average forage scarcity at multi-patch level increases the ratio of searching to feeding time. This results in apparent selective time allocation to richer forage areas but does not imply evidence for oriented movement at a landscape scale. We advance a behavioral-based definition of forage patches and discuss its implications in developing foraging theory and models. The P-S model applied to high-frequency position data of large herbivores substantially improves the interpretation of the factors controlling their time allocation in space with respect to previous models of herbivore spatial behavior by discriminating among behavioral-based and environmentally induced components of their movements. 相似文献
32.
Large and mesoscale meteo-oceanographic patterns in local responses of biogeochemical concentrations
de Oliveira MM Pereira GC de Oliveira JL Ebecken NF 《Environmental monitoring and assessment》2012,184(11):6935-6956
Investigations surrounding the variability of productivity in upwelling regions are necessary for a better understanding the physical-biological coupling in these regions by monitoring systems of environmental impacts according to the needs of the regional coastal management. Using a spatial and temporal database from National Centers for Environmental Prediction (NCEP) and National Center for Atmospheric (NCAR) Research reanalysis, Quick Scatterometer vector wind, and surface stations from the Southeast coast of Brazil, we investigate the meteorological influences due to the large-scale systems in the variability of the nutrient and larvae concentration, and chlorophyll a, describing statistically relationships between them in upwelling regions. In addition, we used multivariate analysis, such as PCA and clustering to verify spatial and temporal variances and describe more clear the structure and composition of the ecosystem. Correlation matrix analyses were applied for different water masses present in the study area to identify the relations between physical and biogeochemical parameters in a region, where frequently upwelling occur. Statistical approaches and seasonal variability show that the period of November to March is more sensitive to nutrients (1.20?mg/m(3) for chlorophyll a, 2.20?μmol/l for total nitrogen and 5.5?ml/l for DO) and larvae concentrations (120 org/m(3) for most of the larvae, except for cirripedia that presented values around 370 org/m(3)) relating to the influence of large and mesoescale meteorological patterns. The spatial and temporal variables analyzed with multivariate approach show meaningful seasonality variance of the physical and biological samples, characterizing the principal components responsible for this variance in spring and summer (upwelling period), emphasizing the monitoring of species as crustaceans and mussels that are present in the local economy. Then, the spring and summer season are characterized by high productivity due to the occurrence of upwelling in this period. 相似文献
33.
Helena Bichão Anna-Karin Borg-Karlson Atle Wibe Jorge Araújo Hanna Mustaparta 《Chemoecology》2005,15(4):211-226
Summary. An important question in insect-plant interactions is which of the numerous plant compounds contribute to the perception of
odour qualities in herbivorous insects and are likely to be used as cues in host-searching behaviour. In order to identify
which plant-produced volatiles the strawberry blossom weevil Anthonomus rubi detects, we have used electrophysiological recordings from single olfactory neurones linked to gas chromatography and mass
spectrometry. We here present 15 receptor neurone types specialised for naturally produced compounds present in the host and
nonhost plants and two types for two aggregation pheromone components. The active compounds were terpenoids, aromatic and
aliphatic esters, alcohols and aldehydes, some of which are induced by feeding activity of the weevils. The neurones were
characterised by a strong response to one or two primary odorants and weaker responses to a few others having similar chemical
structure. With one exception, the molecular receptive range of each neurone type was within one chemical group. Enantiomers
of linalool separated on a chiral column activated two neurone types with different enantioselectivity. Inhibition by linalool
of another neurone type, excited by α-pinene, indicated an additional mechanism for coding the information about this compound.
Altogether, detection of 54 compounds by olfactory receptor neurones is shown, of which 40 have been chemically identified
in this study. Thus A. rubi has the ability to detect a large number of odorants that may be used in host selection behaviour. 相似文献
34.
The present study evaluates the impact of lofts on the development of the navigational system of pigeons. A series of results
obtained between 2000 and 2004 were analyzed. The H-loft was placed 10 m above the ground, with a ring format and seven windows
all around it as well as three external aviaries that allowed birds to have a wide view of the outdoors and of the sky and
knowledge of the wind dynamics. The L-loft was placed at ground level, with a single window transformed into an external aviary.
The L-loft was protected from the wind by surrounding trees, reducing the ability of the pigeons to access the wind dynamics
and also restricting their access to information regarding the outside area and the sky. In a preliminary analysis, we found
the parameter of “vanishing time” to differ significantly between lofts in two of the five age classes. A thorough analysis
of this parameter throughout the ontogenetic development of the birds demonstrated a pronounced improvement in the information-processing
system with age, with adults vanishing quicker than younger birds, although an impairment of development occurred during the
third month of age, perhaps due to a reorganization of the system. This result was obtained when the effect of lofts was considered
in the different age classes. Results suggest that loft features are an important factor in the ability of the young pigeons
to exploit navigational cues. 相似文献
35.
Jorge H. García Matthew T. Heberling Hale W. Thurston 《Journal of the American Water Resources Association》2011,47(1):52-58
García, Jorge H., Matthew T. Heberling, and Hale W. Thurston, 2011. Optimal Pollution Trading Without Pollution Reductions: A Note. Journal of the American Water Resources Association (JAWRA) 47(1):52‐58. DOI: 10.1111/j.1752‐1688.2010.00476.x Abstract: Various kinds of water pollution occur in pulses (e.g., agricultural and urban runoff). Ecosystems, such as wetlands, can serve to regulate these pulses and smooth pollution distributions over time. This smoothing reduces total environmental damages when “instantaneous” damages are marginally increasing. This paper introduces a water quality trading model between a farm (a pulse‐pollution source) and a firm (a more steady pollution source) where the object of exchange is the “temporary” retention of runoff as opposed to total runoff reductions. The optimal trading ratio requires firm emissions to be offset by more than a proportional retention of the initial agricultural runoff pulse. The reason is twofold: (1) emissions are steady or constant over time and, in this sense, have relatively larger environmental impact; and (2) certain kinds of runoff management cause delayed environmental damages. 相似文献
36.
Design of water quality monitoring networks with two information scenarios in tropical Andean basins
Juan Carlos Bastidas Jorge Julián Vélez Jeannette Zambrano Adela Londoño 《Environmental science and pollution research international》2017,24(25):20134-20148
Design and redesign of water quality monitoring networks were evaluated for two similarly sized watersheds in the tropical Andes via optimization techniques using geographic information system technology (GIS) and a matter-element analysis of 5-day biological oxygen demand (BOD5) and total suspended solids (TSS). This resulted in a flexible, objectively based design for a 1128-km2 watershed without prior water quality data (La Miel River), and a network redesign of a 1052-km2 watershed with historical water quality monitoring (Chinchiná River). Monitoring design for the undocumented basin incorporated mathematical expressions for physical, anthropological, and historical factors—and was based on clear objectives for diagnosis and intervention of water pollution. Network redesign identified network redundancy, which resulted in a 64% reduction in the number of water quality monitoring stations along the channel, and a 78% reduction of stations throughout the basin. Most tropical drainage basins throughout the world have little to no prior water quality data. But even in well-studied drainage basins like the Chinchiná River, which is among the most thoroughly studied basins in Colombia, redesign of historical and existing monitoring networks will become a standard tool to advance the restoration of polluted surface waters, not only in Colombia, but also throughout the world. 相似文献
37.
Melina Nisenbaum Gonzalo Hernán Sendr Gastón Alfredo Cerdá Gilbert Marcelo Scagliol Jorge Froilán González Silvia Elena Murialdo 《环境科学学报(英文版)》2013,25(3):613-625
We report on the biodegradation of pure hydrocarbons and chemotaxis towards these compounds by an isolated chlorophenol degrader,Pseudomonas strain H.The biochemical and phylogenetic analysis of the 16S rDNA sequence identified Pseudomonas strain H as having 99.56% similarity with P.aeruginosa PA01.This strain was able to degrade n-hexadecane,1-undecene,1-nonene,1-decene,1-dodecene and kerosene.It grew in the presence of 1-octene,while this hydrocarbons is toxic to other hydrocarbons degraders.Pseudomonas strain H was also chemotactic towards n-hexadecane,kerosene,1-undecene and 1-dodecene.These results show that this Pseudomonas strain H is an attractive candidate for hydrocarbon-containing wastewater bioremediation in controlled environments.Since the classical standard techniques for detecting chemotaxis are not efficient at low bacterial concentrations,we demonstrate the use of the dynamic speckle laser method,which is simple and inexpensive,to confirm bacterial chemotaxis at low cell concentrations (less than 105 colony-forming unit per millilitre (CFU/mL)) when hydrocarbons are the attractants. 相似文献
38.
Guimarães Tábata C. Araújo Everton S. Hernández-Macedo María Lucila López Jorge A. 《Journal of Polymers and the Environment》2022,30(7):2669-2684
Journal of Polymers and the Environment - In recent decades, the global accumulation of plastics and the resulting pollution, as well as the increase in the price of oil, have driven studies aimed... 相似文献
39.
Rethinking receiver operating characteristic analysis applications in ecological niche modeling 总被引:2,自引:0,他引:2
The area under the curve (AUC) of the receiver operating characteristic (ROC) has become a dominant tool in evaluating the accuracy of models predicting distributions of species. ROC has the advantage of being threshold-independent, and as such does not require decisions regarding thresholds of what constitutes a prediction of presence versus a prediction of absence. However, we show that, comparing two ROCs, using the AUC systematically undervalues models that do not provide predictions across the entire spectrum of proportional areas in the study area. Current ROC approaches in ecological niche modeling applications are also inappropriate because the two error components are weighted equally. We recommend a modification of ROC that remedies these problems, using partial-area ROC approaches to provide a firmer foundation for evaluation of predictions from ecological niche models. A worked example demonstrates that models that are evaluated favorably by traditional ROC AUCs are not necessarily the best when niche modeling considerations are incorporated into the design of the test. 相似文献
40.