Population Ecology in Streams

Question 1

What are the two main characteristics of organism population in streams?

Answer 1

Many stream organisms have reproductive stages that are ecologically distinct from juvenile stages (Age / Stage Structure)
Many stream organisms utilize a variety of habitats and have adaptations to move between sites (Meta-populations)

Question 2

What is meta-population and what is the main strength of such populations?

Answer 2

Populations that comprised of subpopulations linked by migration.
Local extinction is a natural process in meta-population dynamics.
Recolonization allows for persistence.

Question 3

Draw the stage.structured population growth, include 5 variables.

Answer 3

· Eggs, larvae, and adults can be counted
· P=Probability
○ P_el= Probability of number of eggs turning into larvae
○ P_la= Probability of number of larvae turning into adults
○ P_ll= Probability of number of larvae staying larvae
○ P_aa= Probability of number of adults staying adult
· F=Fecundity (reproduction)
○ F_ae= How much one adult can produce eggs

Question 4

Make the Leslie Matrix

Question 5

There are two types of production of organisms in streams, what are they? And how do they affect probability of adults staying adults?

Answer 5

○ Semelparous: Organisms that reproduce once in its lifetime
§ P_aa=0
○ Iteroparous: Organisms that reproduce multiple times
§ P_aa≠0,P_aa>0

Question 6

In survivorship curve, there are 3 different types. Draw the curves with survival on y-axis and stage on x-axis.

Answer 6

· Type I: Number of eggs and larvae are really similar to each other, but there is a dip in number of adults compared to number of larvae
· Type II: Dip from eggs to larvae, and from larvae to adults are similar
· Type III: There is a big dip from number of eggs to larvae, but number of larvae and adults is similar