scholarly journals Decay rate of reindeer pellet-groups

Rangifer ◽  
2008 ◽  
Vol 28 (1) ◽  
pp. 47 ◽  
Author(s):  
Anna Skarin
Keyword(s):  
Habitat Use ◽  
Decay Rate ◽  
Rangifer Tarandus ◽  
Accumulation Rate ◽  
Faecal Pellet ◽  
Decay Rates ◽  
Bare Ground ◽  
Pellet Group ◽  
Wildlife Species ◽  
Exponential Decay Rate

Counting of animal faecal pellet groups to estimate habitat use and population densities is a well known method in wildlife research. Using pellet-group counts often require knowledge about the decay rate of the faeces. The decay rate of a faecal pellet group may be different depending on e.g. substrate, size of the pellet group and species. Pellet-group decay rates has been estimated for a number of wildlife species but never before for reindeer (Rangifer tarandus). During 2001 to 2005 a field experiment estimating the decay rate of reindeer pellet groups was performed in the Swedish mountains close to Ammarnäs. In total the decay rate of 382 pellet groups in three different habitat types (alpine heath, birch forest and spruce forest) was estimated. The slowest decay rate was found in alpine heath and there the pellet groups persisted for at least four years. If decay was assumed to take place only during the bare ground season, the estimated exponential decay rate was -0.027 pellet groups/week in the same habitat. In the forest, the decay was faster and the pellet groups did not persist more than two years. Performing pellet group counts to estimate habitat use in dry habitats, such as alpine heath, I will recommend using the faecal standing crop method. Using this method makes it possible to catch the animals’ general habitat use over several years. Abstract in Swedish / Sammanfattning:Nedbrytningshastighet av renspillningInom viltforskningen har spillningsinventeringar använts under flera årtionden för att uppskatta habitatval och populationstäthet hos olika djurslag. För att kunna använda data från spillningsinventeringar krävs ofta att man vet hur lång tid det tar för spillningen att brytas ner. Nedbrytningshastigheten är olika beroende på marktyp och djurslag. Nedbrytningshastighet på spillning har studerats för bland annat olika typer av hjortdjur, men det har inte studerats på ren (Rangifer tarandus) tidigare. I området kring Ammarnäs genomfördes under åren 2001- 2005 ett fältexperiment för att uppskatta nedbrytningshastigheten av renspillning. Under tre somrar lades totalt 382 renspillningar ut i hägn i tre olika typer av habitat (fjällhed, fjällbjörkskog och granskog). Det visade sig att nedbrytningshastigheten var långsammast på fjällheden, där spillningshögarna fortfarande var kvar efter fyra år. Den exponentiella nedbrytningshastigheten beräknades till -0.027 högar/vecka om nedbrytningen antas ske under barmarksperioden. I skogshägnen gick nedbrytningen snabbare och alla högar var borta inom två år. Vid spillningsinventeringar på kalfjällsområdet eller områden med liknande marktyp, där syftet är att studera djurens habitatval över en längre tid rekommenderas att använda den så kallade ”faecal accumulation rate”-metoden, där man inventerar orensade ytor. Det ger en generell bild av hur djuren använt området under en längre period, eftersom nedbrytningen av spillning är långsam i sådana habitat.

scholarly journals Habitat use by semi-domesticated reindeer, estimated with pellet-group counts

Rangifer ◽  
2009 ◽  
Vol 27 (2) ◽  
pp. 121 ◽  
Author(s):  
Anna Skarin
Keyword(s):  
Habitat Selection ◽  
Habitat Use ◽  
Rangifer Tarandus ◽  
Spatial Scales ◽  
Abiotic Factors ◽  
Resource Utilisation ◽  
High Quality ◽  
Human Disturbances ◽  
Pellet Group ◽  
Rangifer Tarandus Tarandus

Habitat selection theory predicts that herbivores should select for or against different factors at different spatial scales. For instance, quantity of forage is expected to be a strong factor influencing habitat choice at large scales, while forage quality may be important at finer scales. However, during summer, herbivores such as reindeer (Rangifer tarandus tarandus) can be limited in their grazing time by insect harassment, and do not always have the possibility to select for high quality forage. Human disturbances from hikers, etc., can also have a limiting effect on the possibility for reindeer to graze in high quality foraging habitats. Reindeer habitat selection at the landscape level was investigated through faecal pellet-group counts during the summers of 2002 and 2003 in two reindeer herding districts in Sweden. Resource utilization functions (RUFs) were developed using multiple linear regressions, where the pellet densities were related to vegetation types, topographic features, distances to tourist resorts, and distances to hiking trails. Validations of the models were performed through cross-validation correlations. Results show that high altitudes with high quality forage were important habitats. Areas that offer both snow patches and fresh forage plants for the reindeer were used in relation to their availability. The reindeer also seemed able to habituate to human intervention to a certain extent. The predictive capabilities of the RUF models were high and pellet-group counts seemed well suited to study how abiotic factors affect the habitat use at large temporal and spatial scales Abstract in Swedish / Sammanfattning: Renens användning av sommarbetesområdet, uppskattat med spillningsinventeringar Hierarkiskt habitatval innebär att djur väljer för och emot olika faktorer beroende på den rumsliga skalan. Mängden bete kan t ex spela stor roll för en växtätares habitatval på en stor skala medan kvalitén på betet kan ha större betydelse på en mindre skala. För renar (Rangifer tarandus tarandus), kan betestiden och möjligheten att hitta bra bete sommartid begränsas både på stor och liten skala pga. störningar från insekter och mänsklig aktivitet. Här studerades renarnas val av betesområde på landskapsnivå med hjälp av spillningsinventering under somrarna 2002 och 2003 i två samebyar i Sverige. Spillningstätheten för respektive område och år undersöktes statistiskt med hjälp av multipel linjär regression eller sk ”resource utilisation functions” (RUF). Där relaterades spillningstätheten till vegetationstyp, olika topografiska faktorer, avstånd till vandringsleder, stugplatser och fjällstationer. Resultaten visade att områden högt upp i terrängen med hög beteskvalitet var attraktiva. Vegetationstypen moderat snölega som anses ha hög beteskvalitet användes av renarna i relation till dess förekomst. Däremot verkade renarna undvika områden kring välbesökta fjällstugor och fjällstationer medan de däremot t o m föredrog områden nära vandringsleder. Det kan bero på att vandringslederna går genom attraktiva vegetationstyper. RUF-modellerna hade en hög prediktiv förmåga vilket visar att spillningsinventeringar är användbara när man önskar studera hur djuren använder ett betesområde i relation till olika faktorer på en relativt stor rumslig och temporal skala.

A Technique for Estimating the Numbers of Eastern Gray Kangaroos, Macropus-Giganteus, Grazing a Given Area of Pasture

1986 ◽  
Vol 13 (3) ◽  
pp. 335 ◽  
Author(s):  
RJ Perry ◽  
ML Braysher
Keyword(s):  
Decay Rate ◽  
Relative Density ◽  
Nature Reserve ◽  
Faecal Pellet ◽  
Absolute Number ◽  
Pellet Group ◽  
Potential Error ◽  
Grey Kangaroo ◽  
Pellet Counts ◽  
Pellet Density

This paper outlines a technique for estimating, by means of faecal pellet counts, the absolute number of eastern grey kangaroos, Macropus giganteus, grazing on a given area in the A.C.T. Absolute numbers were obtained by comparing relative density of pellets on the area to be assessed, with pellet density in the grey kangaroo enclosure at Tidbinbilla Nature Reserve, which has a known area and a known kangaroo population. The decay rate of pellets in three different areas did not vary significantly. The average number of pellets per pellet group was similar in all three areas, but during drought kangaroos tended to drop fewer pellets per group. However, the potential error caused by this can be avoided if the control and test areas are assessed at the same time. The problem of defining a group is eliminated by counting individual pellets rather than groups.

Habitat-specific and season-specific faecal pellet decay rates for five mammalian herbivores in south-eastern Australia

2016 ◽  
Vol 38 (1) ◽  
pp. 105 ◽  
Author(s):  
Naomi E. Davis ◽  
Graeme Coulson
Keyword(s):  
Faecal Pellet ◽  
Decay Rates ◽  
European Rabbit ◽  
Vegetation Types ◽  
Mammalian Herbivores ◽  
Pellet Group ◽  
Eastern Australia ◽  
Pellet Counts ◽  
Common Wombat ◽  
Species Specific

The accuracy of population abundance estimates of mammalian herbivores from faecal pellet counts is potentially affected by pellet decay. We collected fresh pellet groups from hog deer (Axis porcinus), European rabbit (Oryctolagus cuniculus), eastern grey kangaroo (Macropus giganteus), swamp wallaby (Wallabia bicolor) and common wombat (Vombatus ursinus) (n = 300 per species) at Wilsons Promontory National Park, Victoria, Australia. We deposited five pellet groups per species per month within each of five vegetation types in the park, then monitored pellet group decay over 24 months. We demonstrate that age estimation of pellet groups was inaccurate and is unlikely to improve the efficiency of pellet counts. We present habitat- and species-specific estimates of pellet and pellet group decay using two measures: decay rate (the proportion of pellets surviving per unit of time); and mean time to decay. We explain how our data can be used to optimise faecal pellet count design, and to improve the accuracy of both indices and estimates of abundance from pellet counts. The variability observed in the decay of pellet groups among vegetation types, and for species among seasons, suggests that caution should be used if applying pellet decay rates over long time-frames or to locations with differing environmental conditions.

scholarly journals Large deviations for acyclic networks of queues with correlated Gaussian inputs

2021 ◽  
Author(s):  
Martin Zubeldia ◽  
Michel Mandjes
Keyword(s):  
Lower Bound ◽  
Large Deviations ◽  
Decay Rate ◽  
Exponential Decay ◽  
Gaussian Processes ◽  
Sample Path ◽  
Decay Rates ◽  
Single Server ◽  
Exponential Decay Rate ◽  
Overflow Probability

AbstractWe consider an acyclic network of single-server queues with heterogeneous processing rates. It is assumed that each queue is fed by the superposition of a large number of i.i.d. Gaussian processes with stationary increments and positive drifts, which can be correlated across different queues. The flow of work departing from each server is split deterministically and routed to its neighbors according to a fixed routing matrix, with a fraction of it leaving the network altogether. We study the exponential decay rate of the probability that the steady-state queue length at any given node in the network is above any fixed threshold, also referred to as the ‘overflow probability’. In particular, we first leverage Schilder’s sample-path large deviations theorem to obtain a general lower bound for the limit of this exponential decay rate, as the number of Gaussian processes goes to infinity. Then, we show that this lower bound is tight under additional technical conditions. Finally, we show that if the input processes to the different queues are nonnegatively correlated, non-short-range dependent fractional Brownian motions, and if the processing rates are large enough, then the asymptotic exponential decay rates of the queues coincide with the ones of isolated queues with appropriate Gaussian inputs.

scholarly journals Insect avoidance may override human disturbances in reindeer habitat selection

Rangifer ◽  
2004 ◽  
Vol 24 (2) ◽  
pp. 95-103 ◽  
Author(s):  
Anna Skarin ◽  
Öje Danell ◽  
Roger Bergström ◽  
Jon Moen
Keyword(s):  
Wind Speed ◽  
Habitat Selection ◽  
Rangifer Tarandus ◽  
Faecal Pellet ◽  
Reindeer Herding ◽  
Human Disturbances ◽  
Pellet Group ◽  
Direct Observations ◽  
Rangifer Tarandus Tarandus ◽  
Insect Harassment

Habitat selection of semi-domesticated reindeer (Rangifer tarandus tarandus) was investigated through faecal pellet- group counts and by direct observations of reindeer from helicopter in the Långfjället area in Idre reindeer herding district (62˚10’N) and in Mittådalen reindeer herding district (62˚50’N, aerial observations only). Reindeer pellets were found to be most abundant in habitats at high altitudes, and in some vegetation types. Pellet-group densities tended to be higher near the tourist trails, which often follow higher altitudes in the terrain. The aerial surveys showed that the reindeer moved towards higher altitudes when the wind speed was low and the temperature was high both in June and July. In June they moved towards lower regions when temperature was low and the wind speed was strong. The conclusion is that the reindeer use Långfjället to escape insect harassment and warm weather, even though disturbance by tourism sometimes is high.Abstract in Swedish / Sammanfattning:Habitatval hos tamren (Rangifer tarandus tarandus) undersöktes genom att göra en spillningsinventering och genom att göra flygobservationer från helikopter. Studien gjordes på Långfjället (62˚10’N) i Idre nya sameby och i Mittådalens samebys sommarbetesområde (62˚50’N, endast flygobservationer). På Långfjället finns det vandringsleder som är frekventerade av vandrare från juni månad fram till september. Spillningen visade att renarna föredrog höjderna i området samt en del av vegetationstyperna. Det var också mer spillning närmare vandringslederna. Detta kan förklaras av att vandringslederna följer höjderna i terrängen. Flyginventeringarna under både juni och juli visade att renarna rörde sig mot högre terräng när det var varmt och lugnt väder. I juni rörde dom sig också i lägre terräng när det var stark vind och kallt väder. Slutsatsen är att renarna väljer att vistas i högre terräng för att undvika störningar från insekter och för att finna svalka trots att det är mänsklig aktivitet i området.

scholarly journals On the interpretation of annual oscillations in 32Si and 36Cl decay rate measurements

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Pommé ◽  
K. Pelczar ◽  
K. Kossert ◽  
I. Kajan
Keyword(s):  
Decay Rate ◽  
Solar Neutrino ◽  
National Laboratory ◽  
Neutrino Flux ◽  
Measurement Data ◽  
Brookhaven National Laboratory ◽  
Decay Rates ◽  
Dew Point ◽  
Annual Variations ◽  
Set Up

AbstractThe 32Si decay rate measurement data of Alburger et al. obtained in 1982–1986 at Brookhaven National Laboratory have been presented repeatedly as evidence for solar neutrino-induced beta decay. The count rates show an annual sinusoidal oscillation of about 0.1% amplitude and maximum at February–March. Several authors have claimed that the annual oscillations could not be explained by environmental influences on the set-up, and they questioned the invariability of the decay constant. They hypothesised a correlation with changes in the solar neutrino flux due to annual variations in the Earth-Sun distance, in spite of an obvious mismatch in amplitude and phase. In this work, environmental conditions at the time of the experiment are presented. The 32Si decay rate measurements appear to be inversely correlated with the dew point in a nearby weather station. Susceptibility of the detection set-up to local temperature and humidity conditions is a likely cause of the observed instabilities in the measured decay rates. Similar conclusions apply to 36Cl decay rates measured at Ohio State University in 2005–2012.

On the optimality of optical pumping for a closed Λ-system with large decay rates of the intermediate excited state

2021 ◽  
Author(s):  
Dionisis Stefanatos ◽  
Emmanuel Paspalakis
Keyword(s):  
Optimal Control ◽  
Excited State ◽  
Decay Rate ◽  
Optimal Control Theory ◽  
Optical Pumping ◽  
Quantum Information Processing ◽  
Decay Rates ◽  
Population Transfer ◽  
Initial State ◽  
Weakly Coupled

Abstract We use optimal control theory to show that for a closed Λ-system where the excited intermediate level decays to the lower levels with a common large rate, the optimal scheme for population transfer between the lower levels is actually optical pumping. In order to obtain this result we exploit the large decay rate to eliminate adiabatically the weakly coupled excited state, then perform a transformation to the basis comprised of the dark and bright states, and finally apply optimal control to this transformed system. Subsequently, we confirm the optimality of the optical pumping scheme for the original closed Λ-system using numerical optimal control. We also demonstrate numerically that optical pumping remains optimal when the decay rate to the target state is larger than that to the initial state or the two rates are not very different from each other. The present work is expected to find application in various tasks of quantum information processing, where such systems are encountered

scholarly journals Decay of Fecal Indicator Bacterial Populations and Bovine-Associated Source-Tracking Markers in Freshly Deposited Cow Pats

2013 ◽  
Vol 80 (1) ◽  
pp. 110-118 ◽  
Author(s):  
Adelumola Oladeinde ◽  
Thomas Bohrmann ◽  
Kelvin Wong ◽  
S. T. Purucker ◽  
Ken Bradshaw ◽  
...  
Keyword(s):  
Decay Rate ◽  
Fecal Indicator Bacteria ◽  
Decay Rates ◽  
Indicator Bacteria ◽  
Source Tracking ◽  
Fecal Indicator ◽  
Bacterial Populations ◽  
Content Type ◽  
E Coli ◽  
Decay Dynamic

ABSTRACTUnderstanding the survival of fecal indicator bacteria (FIB) and microbial source-tracking (MST) markers is critical to developing pathogen fate and transport models. Although pathogen survival in water microcosms and manure-amended soils is well documented, little is known about their survival in intact cow pats deposited on pastures. We conducted a study to determine decay rates of fecal indicator bacteria (Escherichia coliand enterococci) and bovine-associated MST markers (CowM3, Rum-2-bac, and GenBac) in 18 freshly deposited cattle feces from three farms in northern Georgia. Samples were randomly assigned to shaded or unshaded treatment in order to determine the effects of sunlight, moisture, and temperature on decay rates. A general linear model (GLM) framework was used to determine decay rates. Shading significantly decreased the decay rate of theE. colipopulation (P< 0.0001), with a rate of −0.176 day−1for the shaded treatment and −0.297 day−1for the unshaded treatment. Shading had no significant effect on decay rates of enterococci, CowM3, Rum-2-bac, and GenBac (P> 0.05). In addition,E. colipopulations showed a significant growth rate (0.881 day−1) in the unshaded samples during the first 5 days after deposition. UV-B was the most important parameter explaining the decay rate ofE. colipopulations. A comparison of the decay behaviors among all markers indicated that enterococcus concentrations exhibit a better correlation with the MST markers thanE. coliconcentrations. Our results indicate that bovine-associated MST markers can survive in cow pats for at least 1 month after excretion, and although their decay dynamic differs from the decay dynamic ofE. colipopulations, they seem to be reliable markers to use in combination with enterococci to monitor fecal pollution from pasture lands.

scholarly journals Decision Theory and large deviations for dynamical hypotheses tests: The Neyman-Pearson Lemma, Min-Max and Bayesian tests

2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Hermes H. Ferreira ◽  
Artur O. Lopes ◽  
Silvia R. C. Lopes
Keyword(s):  
Decision Theory ◽  
Large Deviations ◽  
Sample Size ◽  
Decay Rate ◽  
Thermodynamic Formalism ◽  
Exponential Decay Rate ◽  
Log Likelihood ◽  
Two Measures ◽  
Classical Hypothesis ◽  
The Ideal

<p style='text-indent:20px;'>We analyze hypotheses tests using classical results on large deviations to compare two models, each one described by a different Hölder Gibbs probability measure. One main difference to the classical hypothesis tests in Decision Theory is that here the two measures are singular with respect to each other. Among other objectives, we are interested in the decay rate of the wrong decisions probability, when the sample size <inline-formula><tex-math id="M1">\begin{document}$ n $\end{document}</tex-math></inline-formula> goes to infinity. We show a dynamical version of the Neyman-Pearson Lemma displaying the ideal test within a certain class of similar tests. This test becomes exponentially better, compared to other alternative tests, when the sample size goes to infinity. We are able to present the explicit exponential decay rate. We also consider both, the Min-Max and a certain type of Bayesian hypotheses tests. We shall consider these tests in the log likelihood framework by using several tools of Thermodynamic Formalism. Versions of the Stein's Lemma and Chernoff's information are also presented.</p>

scholarly journals Habitat use by mountain nyala Tragelaphus buxtoni determined using stem bite diameters at point of browse, bite rates, and time budgets in the Bale Mountains National Park, Ethiopia

2013 ◽  
Vol 59 (6) ◽  
pp. 707-717 ◽  
Author(s):  
Solomon A. Tadesse ◽  
Burt P. Kotler
Keyword(s):  
Habitat Use ◽  
National Park ◽  
Habitat Type ◽  
Time Budgets ◽  
Non Invasive ◽  
Wildlife Species ◽  
Focal Animal ◽  
Northern Edge ◽  
Browse Species ◽  
Invasive Techniques

Abstract We studied the habitat use of mountain nyala Tragelaphus buxtoni in the northern edge of the Bale Mountains National Park, Ethiopia. The aims of this study were to: (1) measure and quantify habitat-specific stem bite diameters of mountain nyala foraging on common natural plant species in two major habitat types (i.e. grasslands versus woodlands), and (2) quantify the bite rates (number of bites per minute) and the activity time budgets of mountain nyala as functions of habitat type and sex-age category. We randomly laid out three transects in each habitat type. Following each transect, through focal animal observations, we assessed and quantified stem diameters at point of browse (dpb), bite rates, and time budgets of mountain nyala in grasslands versus woodlands. Stem dpb provide a measure of natural giving-up densities (GUDs) and can be used to assess foraging costs and efficiencies, with greater stem dpb corresponding to lower costs and greater efficiencies. The results showed that stem dpb, bite rates, induced vigilance, and proportion of time spent in feeding differed between habitats. In particular, mountain nyala had greater stem dpb, higher bite rates, and spent a greater proportion of their time in feeding and less in induced vigilance in the grasslands. In addition, adult females had the highest bite rates, and the browse species Solanum marginatum had the greatest stem dpb. Generally, grasslands provide the mountain nyala with several advantages over the woodlands, including offering lower foraging costs, greater safety, and more time for foraging. The study advocates how behavioural indicators and natural GUDs are used to examine the habitat use of the endangered mountain nyala through applying non-invasive techniques. We conclude that the resulting measures are helpful for guiding conservation and management efforts and could be applicable to a number of endangered wildlife species including the mountain nyala.

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