What is the difference between additive mortality and compensatory mortality?

If a given mortality factor (Factor X, such as harvest, poisoning or predation) causes an immediate reduction in total survival, it is considered an additive mortality factor. A compensatory factor, in contrast, causes no reduction in total survival (until it reaches some threshold value, C*).

What is compensatory mortality hypothesis?

The compensatory mortality hypothesis predicts that increased harvest mortality of males will reduce population density, resulting in lower competition for resources, reduced natural mortality, and increased reproduction and survival of young.

Is hunting compensatory?

However, when it comes to game species, harvest by humans for recreational or subsistence hunting and trapping can be a source of additive or compensatory mortality depending on when it occurs. … This is true for many species with high reproductive rates and short life spans such as spruce grouse and snowshoe hares.

What is predation a density-dependent?

A second density-dependent limiting factor is predation. Predators kill and eat their prey, of course, so predation increases prey death rate and can cause negative growth rates – population decline.

What does compensatory mortality mean?

Compensatory mortality means that instead of adding additional mortality to the population (i.e., additive mortality), increases in predation result in compensatory declines in other causes of mortality.

What is compensatory mortality?

The compensatory mortality hypothesis postulates that a population’s total mortality remains unchanged at low to interme- diate exploitation rates because natural mortality decreases to compensate for reduced density, whereas the additive mor- tality hypothesis postulates that any increase in exploitation mortality …

What is doomed surplus?

Doomed Surplus Concept. the idea that predation can no effect or have a positive effect, by removing diseased or weak individuals from the population, or by limiting number of babies and allowing the population size to stay constant.

What does apparent competition mean in biology?

Apparent competition occurs when two individuals that do not directly compete for resources affect each other indirectly by being prey for the same predator (Hatcher et al.

What are examples of density-dependent?

Density-dependent factors include competition, predation, parasitism and disease.

What are three examples of density independent limiting factors?

The category of density independent limiting factors includes fires, natural disasters (earthquakes, floods, tornados), and the effects of pollution.

What are examples of density independent factors?

These density-independent factors include food or nutrient limitation, pollutants in the environment, and climate extremes, including seasonal cycles such as monsoons. In addition, catastrophic factors can also impact population growth, such as fires and hurricanes.

What’s an example of predation?

In predation, one organism kills and consumes another. … The best-known examples of predation involve carnivorous interactions, in which one animal consumes another. Think of wolves hunting moose, owls hunting mice, or shrews hunting worms and insects.

What factors can lead to predation to a population?

These factors include, but are not limited to, the amount of food available for the prey, the number of different prey spe- cies available for a predator, and how fast the predator and the prey species reproduce.

How do you calculate LX?

First, the proportion surviving to each life stage (lx) can be found by dividing the number of indivuals living at the beginning of each age (ax) by the initial number of eggs (a0).

What is selective mortality?

Selective mortality is a process whereby disadvantaged individuals die at younger ages than their more advantaged peers. … Interestingly, while it is widely recognized that the composition of aging cohorts changes due to selective mortality, the patterns of such changes have never been published.

What is a predator pit?

A predator pit entails a situation where predation regulates a prey population at constantly low densities. That is, the consumption of prey by predators increases whenever prey populations begin to increase.

Which processes increase a population’s size?

What processes increase a population’s size? Births and immigration. (Immigration is the movement of individuals into a population, so births and immigration increase a population’s size.)

What does R population growth mean?

intrinsic rate of natural increase The constant r is referred to as the intrinsic rate of natural increase (Figure 2). All sorts of microorganisms exhibit patterns that are very close to exponential population growth.

How does predation affect carrying capacity?

Some populations can temporarily “overshoot” their carrying capacity. … For example, the presence of a predator or a parasite can depress the growth rate of a population, but predators and parasites don’t affect carrying capacity unless they reduce the availability of resources.

What is predation and how does it work?

Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the host) and parasitoidism (which always does, eventually).

What are three examples of competition?

Things that are being competed at are: food, water, or space….

What are the 5 types of interaction?

The five major types of species interactions are:

Why is it called apparent competition?

The term apparent competition commonly denotes negative indirect interactions between victim species that arise because they share a natural enemy.

What are 4 examples of density-dependent limiting factors?

Some common examples of density-dependent limiting factors include:

What is the difference between density-dependent and independent?

Density-dependent factors have varying impacts according to population size. … Density-independent factors are not influenced by a species population size. All species populations in the same ecosystem will be similarly affected, regardless of population size. Factors include: weather, climate and natural disasters.

Is a virus density-dependent?

MORV transmission has been found to be density‐dependent (Borremans et al., 2011, 2016; Borremans, Vossen, et al., 2015) and transmission between individuals increases after the breeding season.