APS123 Papers and Practicals

Question 1

What are the five species of warbler in the MacArthur paper?

Answer 1

• Cape May
• Myrtle (yellow-rumped)
• Black-throated green
• Blackburnian
• Bay-breasted

Question 2

When and where are the warblers sometimes found together?

Answer 2

In the breeding season in relatively homogenous mature boreal forests.

Question 3

What do the warblers mainly eat?

Answer 3

Insects

Question 4

What was the aim of the study?

Answer 4

Determining the factors controlling the species’ abundances and preventing all but one from being exterminated by competition

Question 5

What are the two types of events that regulate animal populations?

Answer 5

Density independent (e.g. storms, severe winters, some predation and some disease)
Density dependent (for both occurence and strength), e.g. shortages of food and nesting holes

Question 6

Small areas of habitat typical for one species may…

Answer 6

not contain that species if it is forced out by another species which uses this as a marginal habitat in a heterogeneous environment.

Question 7

MacArthur thinks each species would have to be…

Answer 7

limited by a slightly different factor

Question 8

There are four parts to the study. First, it showed that density…

Answer 8

dependent events play a large role in controlling the populations of the species

Question 9

Secondly, a discussion of..

Answer 9

the general ecology of the species (food, feeding zones, feeding behaviour, territoriality, predators and mortality) is presented

Question 10

Thirdly, the habits

Answer 10

of the different species in different seasons are compared to see what aspects of the general ecology are invariant and hence characteristic of the species

Question 11

Fourth and finally, a wood-to-wood comparison of..

Answer 11

species abundances , relative to the important constituents of their niches as determined in the earlier stages, is presented

Question 12

There tends to be an increase following a decrease, and vice versa, showing that population control is..

Answer 12

non-random

- unknown environmental cycle of approximately 2.5 years

Question 13

MacArthur measured distances down from the top and outward from the trunk of individual …, … and … trees and divided them into zones,….

Answer 13

spruce, fir, pine,

recording feeding positions of the different warblers within each.

Question 14

T3 indicated…

Answer 14

a bird feeding among abundant new needles and buds of the tip of a branch, between 20 and 30 feet from the top of the tree

Question 15

M3 indicated..

Answer 15

feeding mostly among dead needles in the middle zone of a branch at the same height

Question 16

B2 indicated…

Answer 16

a warbler feeding on the bare, lichen-covered base of a branch.

Question 17

In all, … different positions were distinguished

Answer 17

16

- no competitive exclusion as different niches

Question 18

The cape may stayed mostly…

Answer 18

toward the outside at the top

Question 19

The Bay-breasted fed mostly around..

Answer 19

the middle interior

Question 20

The myrtle (yellow-rumped) warbler moved..

Answer 20

from part to part more than the other two

Question 21

The zones that contained… are blackened

Answer 21

50 percent of the birds’ feeding activity

Question 22

Feeding habits differed too. For example…

Answer 22

the cape may warbler catches flying insects more often than the blackburnian and tends to move vertically rather than horizontally.
The black-throated green hovers much more than the bay-breasted.
Myrtle has most varied feeding habits.

Question 23

MacArthur found evidence that food shortage…

Answer 23

limited the size of the warbler populations

Question 24

Overall, macarthur concluded that..

Answer 24

“birds behave in such a way as to be exposed to different kinds of food”

• they also have somewhat different nesting times, and thus the times of their peak food requirements are not the same - partitioning a limiting resource (supply of insects) and in the process occupying different niches).

Question 25

With the orb spider paper, how many islands were monitored and when?

Answer 25

41 islands from 4 years before to 4 years after the Catastrophic Hurricane Floyd passed directly over the site.

Question 26

Before the hurricane, the … … was generally strong and the slope showed no … trend

Answer 26

species-area relationship,

temporal

Question 27

After the hurricane, the slope increased from … … (7 months later) to a value about equal to…

Answer 27

near zero,

its prehurricane state

Question 28

What is the lizard effect?

Answer 28

The difference in spider abundance and species richness between islands with and without the lizard Anolis sagrei

Question 29

The lizard effect was generally … before the hurricane. 7 months later the lizard effect on abundance was … and the effect on richness had …

Answer 29

strong,
weak,
vanished

Question 30

In subsequent years, the lizard effect on … became strong again, but the effect on … remained weak.

Answer 30

abundance,

species richness

Question 31

The strength of the lizard effect on both abundance and species richness over the 8 years was strongly positively related to…

Answer 31

the density of lizards measured on a subset of the study islands

Question 32

Where were the islands located?

Answer 32

Northern bahamas near great Abaco

Question 33

What category was the hurricane?

Answer 33

category IV

Question 34

Two months after the hurricane, spider densities averaged only … of the last recorded values 7 months earlier

Answer 34

1.7%

Question 35

Before the hurricane, spider abundance showed a steady but small decline on islands … … and no trend on islands … …

Answer 35

without lizards,

with lizards

Question 36

Abundance was lower…

Answer 36

on islands with lizards (averaged 60% of that on no-lizard islands)

Question 37

Species richness showed a … trend before the hurricane on both lizardy and non-lizardy islands

Answer 37

downward

Question 38

The slope of the species-area relation showed…

Answer 38

essentially full recovery after 3 years