DYNAMIC BEHAVIOR OF PREDATOR-PREY WITH RATIO DEPENDENT, REFUGE IN PREY AND HARVEST FROM PREDATOR

Abstract In this paper, we discuss a dynamical behavior of Predator-Prey with ratiodependent, refuge in prey, and harvest from predator. Model reconstruction isorganized by adding the refuge control in prey with the values 0 m 1, and linearpredator harvesting. The aim of analysis is to describe the equilibrium points andtheir stability. In analysis, the possible fixed points are the prey extinction, thepredator extinction, and predator-prey coexists. By using linearization, thestability of predator extinction point is unstable, and the prey extinction point,coexists point becomes stable with certain condition. Finally, the dynamicalsimulation show that the trajectories of solution convergent to their stability, andthe refuge strategy suitable to avoid the extinction of prey.Key Word: Dynamic Behavior, Predator-Prey, Predation, Refuges, Harves

Dynamical Behavior of an Eco-epidemiological Model Incorporating Prey Refuge and Prey Harvesting

In this paper an eco-epidemiological model incorporating a prey refuge and prey harvesting with disease in the prey-population is considered. Predators are assumed to consume both the susceptible and infected prey at different rates. The positivity and boundedness of the solution of the system are discussed. The existence and stability of the biologically feasible equilibrium points are investigated. Numerical simulations are performed to support our analytical findings

(R1493) Discussion on Stability and Hopf-bifurcation of an Infected Prey under Refuge and Predator

The paper deals with the case of non-selective predation in a partially infected prey-predator system, where both the susceptible prey and predator follow the law of logistic growth and some preys avoid predation by hiding. The disease-free preys get infected in due course of time by a certain rate. However, the carrying capacity of the predator population is considered proportional to the sum-total of the susceptible and infected prey. The positivity and boundedness of the solutions of the system are studied and the existence of the equilibrium points and stability of the system are analyzed at these points. The effect of the infected prey-refuge on each population density is also discussed. It is observed that a Hopf-bifurcation may occur about the interior equilibrium, where the refuge parameter is considered as the bifurcation parameter. The analytical findings are illustrated through computer simulation using MAPLE that show the reliability of the model from the ecological point of view

On an Ecological Model of Mutualisim Between Two Species With a Mortal Predator

In this paper, we study an ecological model of a three-space food chain consists of two logically growing mutual species and third species acts as a predator to second mutual species with Holling type II functional response. This model is constituted by a system of nonlinear decoupled ordinary differential equations. By using perturbed method, we identify the nature of the system at each equilibrium point and also global stability is investigated for this model using Lypanov function at the possible equilibrium points

Predation research with electronic tagging

Predation is a fundamental aspect of ecology that drives ecosystem structure and function. A better understanding of predation can be facilitated by using electronic tags that log or transmit positions of predator or prey species in natural settings, however, there are special considerations that must be made to avoid biased estimates. We provide an overview of the tools available for studying predation with electronic tags including the tag types and analytical tools that can be used to identify where, when and how prey are killed by predators. We also discuss considerations for experimental design when studying predation using electronic tags, including how to minimize effects of capture and tagging procedures. Ongoing innovation and integration of sensors for tags will provide more detailed data about the performance of tagged predators and the fate of tagged prey. Where analysts can effectively resolve the timing of predation using state-of-the-art tags and analytical tools, we foresee exciting advances in our understanding of animal demographics, evolutionary trajectories and management systems. Prospects to develop new tools and approaches for tracking predation while designing studies to more effectively limit bias are an important frontier for understanding ecosystems and addressing human–wildlife conflicts. Given great uncertainties about environmen-tal change and intensifying conflicts between humans and predators, effective study designs integrating electronic tagging to study predation have a promising future in fundamental and applied ecologypublishedVersio

Dynamics of Predator-prey Model under Fluctuation Rescue Effect

This paper presents a novel idea as it investigates the rescue effect of the prey with fluctuation effect for the first time to propose a modified predator-prey model that forms a non-autonomous model. However, the approximation method is utilized to convert the non-autonomous model to an autonomous one by simplifying the mathematical analysis and following the dynamical behaviors. Some theoretical properties of the proposed autonomous model like the boundedness, stability, and Kolmogorov conditions are studied. This paper's analytical results demonstrate that the dynamic behaviors are globally stable and that the rescue effect improves the likelihood of coexistence compared to when there is no rescue impact. Furthermore, numerical simulations are carried out to demonstrate the impact of the fluctuation rescue effect on the dynamics of the non-autonomous model. The analytical and numerical results show a more coexisted model between prey and predator, which can help any extinction-threatened ecosystem

A synthesis of scale-dependent ecology of the endangered mountain caribou in British Columbia, Canada

Mountain caribou are an endangered ecotype of woodland caribou (Rangifer tarandus caribou) that live in highprecipitation, mountainous ecosystems of southeastern British Columbia and northern Idaho. The distribution and abundance of these caribou have declined dramatically from historical figures. Results from many studies have indicated that mountain caribou rely on old conifer forests for several life-history requirements including an abundance of their primary winter food, arboreal lichen, and a scarcity of other ungulates and their predators. These old forests often have high timber value, and understanding mountain caribou ecology at a variety of spatial scales is thus required to develop effective conservation strategies. Here we summarize results of studies conducted at three different spatial scales ranging from broad limiting factors at the population level to studies describing the selection of feeding sites within seasonal home ranges of individuals. The goal of this multi-scale review is to provide a more complete picture of caribou ecology and to determine possible shifts in limiting factors across scales. Our review produced two important results. First, mountain caribou select old forests and old trees at all spatial scales, signifying their importance for foraging opportunities as well as conditions required to avoid alternate ungulates and their predators. Second, relationships differ across scales. For example, landscapes dominated by roads and edges negatively affect caribou survival, but appear to attract caribou during certain times of the year. This juxtaposition of fine-scale behaviour with broad-scale vulnerability to predation could only be identified through integrated multi-scale analyses of resource selection. Consequently we suggest that effective management strategies for endangered species require an integrative approach across multiple spatial scales to avoid a focus that may be too narrow to maintain viable populations. Abstract in Norwegian / Sammendrag:Skala-avhengig økologi og truet fjellvillrein i Britisk ColumbiaFjellvillreinen i de nedbørsrike fjellområdene i sørøstre Britisk Columbia og nordlige Idaho som er en truet økotype av skogsreinen (Rangifer tarandus caribou), har blitt kraftig redusert både i utbredelse og antall. Mange studier har vist at denne økotypen er avhengig av vinterføden hengelav i gammel barskog hvor det også er få andre klovdyr og dermed få predatorer. Slik skog er også viktige hogstområder, og å forstå økologien til fjellvillreinen i forskjellige skaleringer er derfor nødvendig for å utvikle forvaltningsstrategier som kan berge og ta vare på denne reinen. Artikkelen gir en oversikt over slike arbeider: fra studier av begrensende faktorer på populasjonsnivå til studier av sesongmessige beiteplasser på individnivå. Hensikten er å få frem et mer helhetlig perspektiv på fjellvillreinen og finne hvordan de begrensende faktorene varierer etter skaleringen som er benyttet i studiet. Oversikten vår frembragte to viktige resultater; 1) Uansett skalering så velger dyrene gammel skog og gamle trær. 2) Dyrenes bruk av et område kan variere med benyttet skalering, for eksempel vil landskap utbygd med veier og hogstflater være ufordelaktig for overlevelsen, men synes likevel å kunne tiltrekke fjellvillreinen til visse tider av året. Forholdet mellom atferd ut fra fin-skalering og stor-skalering sårbarhet hva gjelder predasjon, ville kun blitt avdekket ved flere-skaleringsanalyse av hvordan ressursene benyttes. Ut fra dette foreslår vi at forvaltningsstrategier for truete bestander som eksempelvis fjellvillreinen, må baseres på tilnærminger ut fra ulike skaleringer for å hindre at et for snevert perspektiv kan begrense muligheten for vedvarende levedyktighet

Positive Indirect Interactions in Marine Herbivores and Algae

There is an increasing interest in how nested positive indirect interactions involving at least three species maintain community structure. Recent research shows that positive indirect effects can strongly influence community structure, organisation and functioning. It is thus important to understand and identify positive indirect effects for the purpose of predicting system responses to certain perturbations. In order to investigate indirect effects, experimental manipulations must be carried out within the entire framework of the community of interest. Hence, often due to logistical difficulties, indirect effects, especially those that yield positive results, have been less studied. Here we present a synthesis of current information on patterns of positive indirect effects and review and compare recently conducted experimental studies in marine herbivores and algae

The Ecological Ramifications of Disease and Density in the Caribbean Spiny Lobster, \u3ci\u3ePanulirus argus\u3c/i\u3e

In 1999, I discovered the first virus known to be pathogenic to any species of lobster. HLV-PA is a pathogenic herpes-like virus that infects juvenile Caribbean spiny lobster, Panulirus argus, in the waters off south Florida (USA), and it alters the behavior and ecology of this species in fundamental ways. Gross signs of HLV-PA infection are lethargy, morbidity, cessation of molting, and discolored, “milky” hemolymph that does not clot. HLV-PA infects the hemocytes of host lobsters, specifically the hyalinocytes and semi-granulocytes, but not the granulocytes. When hemolymph from infected donors was injected into healthy juvenile lobsters, 90% of the healthy individuals became infected within 80 days. In another set of laboratory trials, 40% of the juvenile lobsters that ingested conspecific tissue infected with HLV-PA developed the disease, and in a third experiment wherein transmission by contact or waterborne means was tested, 63% of the lobsters(CL), 33% of lobsters 30–40 mm CL and 10% of lobsters 40–50 mm CL became infected within 80 days. In field surveys from 2000–2001, up to 40% of the juveniles at each of twelve sites (mean = 8%) had the disease. The disease was most prevalent (mean = 16%) among the smallest juveniles (i.e.,CL) and, thus far, appears limited to juveniles. However, all of the surveys of disease prevalence are based on gross, visual signs of late stages of infection, and are, therefore, conservative estimates. A diagnostic tool to assess infection at earlier stages has not yet been developed. Field observations and laboratory experiments indicate that healthy juvenile lobsters avoid diseased conspecifics, which is only the second report of such behavior in any animal. The prevalence of the disease in wild lobster populations is not correlated with population density, even when lobsters were experimentally concentrated at sites with artificial shelters. Moreover, enhanced density does not appear to have a detrimental effect on population dynamics such as nutritional condition and short-term residency, likely due to their normal gregariousness. Thus, juvenile spiny lobsters appear to have developed remarkable contradictory behaviors, avoidance of infected conspecifics and gregariousness, both of which may ultimately enhance survival of uninfected lobsters