Carrying Capacity

1. Carrying Capacity K-Strategists & r-Strategists

2. Carrying Capacity • Carrying Capacity (K) – the limiting value of a population that a particular environment can support • Populations below K will grow exponentially • Maximum rate of increase for any population is the positive growth rate • K − NKcan be used to express the growth realization factor of populations.

3. Carrying Capacity • If the size of the population (n) is far below the carrying capacity of the environment (K), the growth realization factor will be close to 1, and the population will show exponential growth. • But as n begins to approach K, the growth realization factor approaches zero, and the rate of population drops to zero

4. Carrying Capacity • Plotting the growth of a population from an initial growth realization factor of 1 to a final factor of 0 produces a curve like this, called the logistic growth curve or S-shaped curve of growth.

5. r-strategists share these features: • They are usually found in disturbed and/or transitory habitats. • They have efficient means of dispersal to new habitats. • They have short life spans. • They begin breeding early in life. (Early maturity)

6. r-strategists continued: • They usually have short generation times. • They produce large numbers of offspring. • They take little care of their offspring, and infant mortality is high. • Density independent

7. Typically, K-strategists share these qualities: • They are usually found in stable habitats. • K-strategists typically have evolved in such a way that they become increasingly efficient at exploiting an ever-narrower slice of their environment. • They have long life spans. • They begin breeding later in life. (Slow maturity)

8. K-strategists continued: • They usually have long generation times. • Most produce small numbers of offspring. • They take good care of their young. Infant mortality tends to be low. • Density dependent