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Trophic Interactions during Primary Succession
Trophic Interactions during Primary Succession

... critical to understanding mechanisms underlying ecological pattern formation. Here we adopt a spatial perspective afforded by ecological invasion theory to investigate the impacts of insect herbivores on the dynamics of a plant, Lupinus lepidus, that is colonizing primary successional habitat at Mou ...
Cannibalism amplifies the spread of vertically transmitted pathogens
Cannibalism amplifies the spread of vertically transmitted pathogens

... The surviving larvae emerge to the adult population We developed a stochastic, individual-­ based model that simulates organisms that utilize discrete larval hab- of the next generation. Thus, the adult population is conitats such as stem borers, leaf miners, tephritid flies, par- stant over time af ...
Evolutionary Tradeoff and Equilibrium in an Aquatic Predator–Prey
Evolutionary Tradeoff and Equilibrium in an Aquatic Predator–Prey

... (ESC = evolutionarily stable combination). We then use the results of this analysis to predict how population response to changing conditions will be modified by adaptive changes in the prey. The model can produce a wide range of dynamic behavior depending on parameters. A complete analysis of its b ...
cod on the southern scotian shelf and in the bay of fundy (div. 4x/5y)
cod on the southern scotian shelf and in the bay of fundy (div. 4x/5y)

... domestic and foreign otter trawl fleets joined the predominantly hook and line fishery (Fig. 1), then dropped in 1970 as effort declined due to restrictions on haddock fishing. Landings declined through the 1990’s as the total allowable catch (TAC) was reduced. The TAC was set at 6,000t for three ye ...
Life history traits contribute to decline of critically endangered lizards
Life history traits contribute to decline of critically endangered lizards

... captures. In total, populations were sampled 18 times over the 6-year study with the exception of population E (a grand skink pastureland site; Fig. 1), which was not visited in November 1996. For any given sampling session, each population was visited over multiple non-consecutive days as weather a ...
Ten Commandments for Ecosystem-Based Fisheries Scientists Diez
Ten Commandments for Ecosystem-Based Fisheries Scientists Diez

... This is a critical commandment for any kind of science, but is particularly true for science which is advisory to fishery management decisions. For example, the most common and sophisticated single-species stock assessment models often assume that: (1) recruitment is solely a function of spawning bi ...
The concept of overgrazing and its role in management of
The concept of overgrazing and its role in management of

... Overgrazing has been described related to pastoral systems in Africa (Mace 1991), rangelands of the United States (McNaughton 1979) and wetland and riparian areas (van de Koppel et al. 1999). Also famous are examples from Australia (Caughley et al. 1997) and New Zea­ land (Nugent et al. 2001, Coomes ...
Queensland Wildlife Trade Management Plan for Export
Queensland Wildlife Trade Management Plan for Export

... 2 Legislative and regulatory framework 2.1 Commonwealth The relevant provisions under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) came into force on 11 January 2002, following the incorporation of the former Wildlife Protection (Regulation of Exports and Imports) Act ...
Changing Seascapes, Stochastic Connectivity, and Marine
Changing Seascapes, Stochastic Connectivity, and Marine

... arise from the underlying oceanography. For example, oceanographic features, such as alongshore jets, can connect multiple sites at the same time, resulting in positive covariances between multiple connections (Mitarai et al. 2009). Concurrently, these features can also disconnect sites, leading to ...
An Evaluation of Feral Cat Management Options Using a Decision
An Evaluation of Feral Cat Management Options Using a Decision

... is composed of states of nature nodes, such as population status; decision nodes, such as alternative feral cat management schemes; and a utility node, which incorporates operational costs and societal values. The overall model is graphically represented as an influence diagram in Figure 1. Figure 2 ...
The Canadian Seal Hunt: No Management and
The Canadian Seal Hunt: No Management and

... 1986-1995. In recent years, 4,000-6,000 hooded seals have been taken in native subsistence hunts in Greenland, with a further 100 or so in northern Canada. Icelandic hunters shoot an unknown number annually. ...
Michigan Department of Natural Resources 2008-56 Status of the Fishery Resource Report
Michigan Department of Natural Resources 2008-56 Status of the Fishery Resource Report

... survey. They maintained that greatly increased spearing pressure, occurring when the pike are concentrated during the winter drawdown, had resulted in an over-exploitation of this species as evidenced by their smaller size. Fisheries Division personnel distributed scale envelopes to various resorts ...
Adaptive omnivory and species coexistence in tri
Adaptive omnivory and species coexistence in tri

... According to the diet rule, a less profitable prey will be dropped from the diet whenever the densities of more profitable prey items exceed some threshold value. It thus seems plausible to hypothesize that optimal foraging according to the diet rule might facilitate persistence of the intermediate co ...
Evaluating the effect of predation mortality on forage species
Evaluating the effect of predation mortality on forage species

... fisheries science and management is becoming increasingly apparent (Pope, 1991; Yodzis, 2001; Link, 2002). Several models exist to do this (e.g. Hollowed et al., 2000; Whipple et al., 2000; Plagányi, 2007), and among them are several multispecies models that utilize combined aspects of common fishe ...
Population dynamic theory of size
Population dynamic theory of size

... predator–prey model in which the cannibalistic predator consumes both alternative prey and conspecifics. In the absence of cannibalism the model reduces to the McArthur–Rosenzweig model and predicts predator–prey cycles. If cannibalism is introduced, the cycles are damped, and with a sufficient cann ...
Predation and caribou populations
Predation and caribou populations

... densities can reduce both the functional and numerical response of predators. However, that antipredator strategy is only effective if caribou are the primary prey species in the area. Forest-dwelling caribou populations throughout North America have undergone major declines during the 1900's (Berge ...
Growth, development, and life-history strategies in an unpredictable
Growth, development, and life-history strategies in an unpredictable

... in seasonal environments). Often size has a closer association with fitness than development time does, so many animals delay sexual maturation to increase in size despite the costs (Reznick, 1990). However, when conditions are poor individuals may sometimes initiate diapause to make the ‘best of a ...
Density dependence and population regulation in marine fish: a
Density dependence and population regulation in marine fish: a

... survival to adulthood, and fecundity. These local populations also displayed components of regulation: persistence, boundedness, and return tendency. Reefs supporting regulated populations were structurally complex, providing sufficient prey refuges that ensured high survival at low densities. In con ...
CRB_Monit_Frwk_2Nov09-both
CRB_Monit_Frwk_2Nov09-both

... The salmonid monitoring sub-framework outlined here includes (1) anadromous fish population status and trend criteria, specifically Viable Salmonid Population (VSP) metrics (2) artificial production effectiveness, and (3) habitat effectiveness monitoring. These three are components of a broader moni ...
recruitment limitation and population density in the harvester ant
recruitment limitation and population density in the harvester ant

... In this study we define the local neighborhood as the collection of individuals that shares the same ecological site characteristics and which can directly interact with one another. For different organisms, this means different scales of interaction. We have used 0.25 ha plots to subdivide the stu ...
The Effect of Density-Independent Mortality on the Coexistence of
The Effect of Density-Independent Mortality on the Coexistence of

... relationship applies to the broadest range of resource requirements, d, when C is very small (i.e., when there is little overlap in resource use). If the range of d allowing coexistence is integrated over all possible values of C, the same qualitative result emerges. The parameter C only determines ...
The need for integrative approaches to understand and conserve
The need for integrative approaches to understand and conserve

... been inspired by concern over population declines in migratory birds, with neotropical species breeding in North America receiving much of the attention (e.g. Stotz et al. 1996). When a migratory population declines, its reliance on at least two different locations begs the question: in which habita ...
White sturgeon, Shovelnose sturgeon, American Paddlefish U.S.
White sturgeon, Shovelnose sturgeon, American Paddlefish U.S.

... About Seafood Watch® The Monterey Bay Aquarium Seafood Watch® program evaluates the ecological sustainability of wild-caught and farmed seafood commonly found in the North American marketplace. Seafood Watch defines sustainable seafood as originating from sources, whether wild-caught or farmed, whi ...
Stochasticity, predator-prey dynamics, and trigger - Sabo Lab
Stochasticity, predator-prey dynamics, and trigger - Sabo Lab

... FIG. 1. Increased prey extinction mediated by environmentally driven stochasticity, or ‘‘process noise’’ in the predator population growth rate. Top: Analytical deterministic model dynamics. (a) Stability conditions for the deterministic predator prey model (Eqs. 1 and 2) in terms of prey carrying c ...
Effects of exploitation on an overabundant species: the lesser snow
Effects of exploitation on an overabundant species: the lesser snow

... 3. Historically, juvenile snow geese suffered from density-related degradation of their saltmarsh brood-rearing habitat. This allowed harvest mortality to be partially compensated by nonharvest mortality (process correlation between mortality sources: q = 047; 90% BCI: 072 to 004). Snow goose ...
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Maximum sustainable yield

In population ecology and economics, maximum sustainable yield or MSY is theoretically, the largest yield (or catch) that can be taken from a species' stock over an indefinite period. Fundamental to the notion of sustainable harvest, the concept of MSY aims to maintain the population size at the point of maximum growth rate by harvesting the individuals that would normally be added to the population, allowing the population to continue to be productive indefinitely. Under the assumption of logistic growth, resource limitation does not constrain individuals’ reproductive rates when populations are small, but because there are few individuals, the overall yield is small. At intermediate population densities, also represented by half the carrying capacity, individuals are able to breed to their maximum rate. At this point, called the maximum sustainable yield, there is a surplus of individuals that can be harvested because growth of the population is at its maximum point due to the large number of reproducing individuals. Above this point, density dependent factors increasingly limit breeding until the population reaches carrying capacity. At this point, there are no surplus individuals to be harvested and yield drops to zero. The maximum sustainable yield is usually higher than the optimum sustainable yield and maximum economic yield.MSY is extensively used for fisheries management. Unlike the logistic (Schaefer) model, MSY has been refined in most modern fisheries models and occurs at around 30% of the unexploited population size. This fraction differs among populations depending on the life history of the species and the age-specific selectivity of the fishing method.However, the approach has been widely criticized as ignoring several key factors involved in fisheries management and has led to the devastating collapse of many fisheries. As a simple calculation, it ignores the size and age of the animal being taken, its reproductive status, and it focuses solely on the species in question, ignoring the damage to the ecosystem caused by the designated level of exploitation and the issue of bycatch. Among conservation biologists it is widely regarded as dangerous and misused.
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