Plant Community Ecology Test #2 From Study Guide

Front 1

Dimension Reduction

Back 1

Process of collapsing highly multivariate data into a small number of dimensions

Front 2

Monte Carlo Methods

Back 2

Used to determine if your result has meaning

Front 3

Eigenvalue

Back 3

Contribution of each axis to total variance

Front 4

Agglomerative Vs. Divisive Classification

Back 4

Agglomerative: starts with all different and goes until all are in one group. Divisive: assumes all same, then divides down to some criterion. (preferred, but few and far between)

Front 5

Non-Hierarchical Classification

Back 5

tries to find natural breaks in data swarms in n-dimensions. Few good methods exist

Front 6

Indicator Species

Back 6

The concept of using species to identify factors in the environment

Front 7

Niche

Back 7

Range of ecological conditions in which a plant species will grow

Front 8

Competitive Exclusion

Back 8

Species use same limiting resource, in same place, in stable and uniform habitat, for sufficiently long time

Front 9

Mass Effect

Back 9

Species go extinct except that there is continual replenishment from surroundings

Front 10

Ecological Equivalence

Back 10

where several similar species co-occur, first-come first served, and once served, your in for the duration

Front 11

Niche Differentiation

Back 11

species shift their requirements to reduce impact (evolutionary response)

Front 12

Species Area Curve

Back 12

Log area vs log richness; the steeper the line the faster species accumulate

Front 13

Competition

Back 13

The negative effects which one organism has upon another by consuming or controlling access to a resource that is limited in availability

Front 14

Allelopathy

Back 14

Chemical inhibition of the growth of one organism over another

Front 15

Diffuse Competition

Back 15

Target impacted in proportion to the biomass of associates (cumulative effects of neighbors of all species)

Front 16

Predominant Competition

Back 16

One species is main contributor to intensity

Front 17

Symmetric vs. Asymmetric Competition

Back 17

species affect each other equally vs one species has greater affect than other species

Front 18

Safe-site (microsite)

Back 18

A favorable spot for seed germination and establishment

Front 19

Preemption

Back 19

Getting to the resource first

Front 20

Tolerence

Back 20

Coping with the limitation

Front 21

Efficiency

Back 21

Better use of resource

Front 22

Succession

Back 22

Directional change in community composition and structure through time

Front 23

Mechanisms of Succession (6)

Back 23

Nudation, migration, establishment, facilitation, competition, stabilization

Front 24

Facilitation

Back 24

Positive interactions among plants; a process by which early successional species increase the survival of later successional species

Front 25

Inhibition

Back 25

A process by which early successional species decrease the survival of later succesional species

Front 26

Nudation

Back 26

Process that clears the land

Front 27

Migration

Back 27

The movement of organisms or propagules

Front 28

Establishment

Back 28

growing up

Front 29

Stabilization (Climax)

Back 29

The hypothetical equilibrium end point of a successional sequence

Front 30

Chronosequence

Back 30

A set of communities of different ages since disturbance, assumed to represent a single community over time

Front 31

Wetlands

Back 31

Transitional habitats with plants normally rooted in saturated soils with plants adapted to living in water or saturated soils

Front 32

Soil Chroma

Back 32

Intensity

Front 33

Paulustrine

Back 33

non-tidal wetlands dominated by trees, shrubs, emergents, mosses/lichens and tidal wetlands under 0.5 ppt. Common non-tidal system

Front 34

Lacustrine

Back 34

All the following: wetlands in depressions or dammed river channels, lacking trees, shrubs, emergents with 30% cover; larger than 20 acres.

Front 35

Jessica Gurevitch

Back 35

Large plants have large immediate neighbors, small plants have small immediate neighbors (mosaic of patches) probably due to patchy resources

Front 36

John Harper

Back 36

one of pioneers of plant community ecology; safe-sites

Front 37

David Tilman

Back 37

In communities on infertile soils with low productivity, species that are superior competitors for soil nitrogen should be competitively dominant

Front 38

Peter Grubb

Back 38

differences among species in the conditions and circumstances required for germination and establishment might be an important factor in species coexistence (regeneration niche)

Front 39

Deborah Goldberg

Back 39

strong effects of density on seedling emergence

Front 40

Norma Fowler

Back 40

Competition much less important than other factors in some perennial grasses

Front 41

Paul Keddy

Back 41

Competitive effect increases with increased growth rate

Front 42

Mark Westby

Back 42

Trade-offs along a small number of axes that define major, easily quantified traits, wants to reduce vast diversity of terrestrial plants to conceptual categories so that plants can be grouped in ways that enable one to pose testable hypotheses and make predictions

Front 43

C. H. Muller

Back 43

research on allelopathy in chaparals

Front 44

Ragan Calloway

Back 44

allelopathy as cause of succession in invasive weeds

Front 45

S.T.A. Pickett

Back 45

disturbance is a relatively discrete event in time that causes abrupt change in ecosystem, community, or population structure and changes resource availability, substrate availability, or physical environment

Front 46

Henry Cowles

Back 46

succession of dunes, chronosequence

Front 47

Why is a dendrogram hard to interpret?

Back 47

Larger groups have more variation so differences can be exaggerated. Can be divise or agglomerative (makes dendrogram for you).

Front 48

What is chaining?

Back 48

Dendrogram has less definitive subgroups. Low chaining means there is high dichotomous branching.

Front 49

What properties of the data affect dendrogram structure?

Back 49

Richness and group size

Front 50

Why shouldn’t you attempt to draw a line across a dendrogram to form vegetation units?

Back 50

Line lengths do not necessarily suggest connectivity with close neighbors.

Front 51

Contrast TWINSPAN with any typical agglomerative strategy.

Back 51

TWINSPAN is divisive.

Front 52

What are the main purposes of classification?

Back 52

To summarize large, complex sets of data to produce mapping units; reduce data to manageable levels; help interpret environmental factors; test community hypotheses; refine models of community structure; assist experimental design

Front 53

List several reasons to do a classification, even if you believe your data represent continuous variation.

Back 53

Different results from alternative methods can reveal unsuspected aspects of data; same results from different analyses give credence to real discontinuities in the data.

Front 54

List five subjective aspects of doing classification.

Back 54

Altternative methods produce alternative results; different observers may reach different conclusions; different subset of data might lead to different classification; transformations may emphasize dominance or rare sp.; editing rare species can make groups more homogenous, or can obscure real differences among samples.

Front 55

What might happen if you remove just one plot from your data set?

Back 55

Depends. Could remove branch from dendrogram, nothing

Front 56

Describe how you would use classification in the study of succession using permanent plots.

Back 56

Look at vegetation types to classify level of succession.

Front 57

How can you tell if your vegetation classes represent unique clusters?

Back 57

Want space between a branch on dendrogram to be smaller than space between 2 branches on dendrogram; if there’s not species overlap between groups.

Front 58

What factors might control diversity within a 1 ha vegetation sample.

Back 58

Site history, soil, moisture, seed dispersal, temperature, competition, facilitation, tolerance (can survive under less than optimal conditions)

Front 59

Discus those factors that may permit the coexistence of similar perennial herbaceous species in the coniferous forest understory.

Back 59

Availability of different microsites, tolerance, minimal competition, habitat fluctuation, facilitation

Front 60

What factors might influence diversity gradients on a broad geographic scale?

Back 60

Consider productivity, stability, biotic factors, habitat complexity and disturbance.

Front 61

What factors lead to there being more species in samples of East Cascade than West Cascade forests?

Back 61

Temperature gradient, moisture gradient (rain on west, none on east), disturbance regimes (farming east, logging west). West more homogenous, has forest—trees prevent understories, East has weedy species.

Front 62

List factors that might affect changing numbers of plant species along a latitudinal gradient (N to S)

Back 62

Wind, temperature, precipitation, Hadley cells, site history, habitat modification.

Front 63

A seed germinated in a meadow, but died within a few weeks. Briefly, discuss how you could determine if competition was responsible for this death. Observe what happens after seed dies. How could you determine if a particular competitor species was responsible?

Back 63

Manipulation experiments; Selective removal, replant same seed.

Front 64

You encounter a meadow surrounded by tall conifers. Aerial photos indicate that the meadow has been there for 75 years, and that it has been fallow (not cultivated) for at least 60 years. List the potential reasons that explain why conifers have not invaded; for each, list an experiment or observation to test predictions based on each reason (hypothesis).

Back 64

Soil differences, herbivory (put fence around), more drainage, remove grasses, plant sapling (see if it’s something before that preventing it).

Front 65

List at least four factors that are most likely to permit the coexistence of closely similar herbaceous perennial species in the coniferous forest understory.

Back 65

Niche differentiation (temporal avoidance, morphological avoidance, different shade requirements, limited by different factors), Abundant resources, habitat heterogeneity, habitat fluctuation.

Front 66

What factors make it hard to study competition?

Back 66

You might consider spatial effects, competitive balance that shifts in space, multi-species effects, and others. Diffuse competition, control of vegetation might be layered

Front 67

What factors permit coexistence by allowing plants to avoid competition? What nine factors may allow plants to coexist within the same habitat?

Back 67

Niche differentiation, different regeneration regimes, habitat heterogeneity, habitat fluctuation, abundant resources, chronic disturbance, balanced competition, equivalence, mass effect.

Front 68

Recall the concept of competitive hierarchies (the centrifugal model). If the model is correct, what happens if you remove Typha from the system?

Back 68

Change successional trajectory; something else will take over/grow

Front 69

What is the difference between the regeneration niche (Grubb) and a safe-site (Harper)?

Back 69

R: more about attributes that allow for regeneration, S: more geared towards colonization/germination

Front 70

How does the “carousel model” (van der Maarel) help to explain local (alpha) diversity?

Back 70

Cyclical succession.

Front 71

You sampled old-growth conifer forests in 7 small lowland valleys within one large watershed. As far as you can tell or measure, the environments are similar. You classify them objectively into seven groups, each comprised only of samples from a single valley. If the species composition of each is stable, list three important reasons that could produce seven different "climax" forests within the same area.

Back 71

Site history, unmeasured variables (latent factors), poor models, imprecise measures, seed dispersal

Front 72

What are the advantages of permanent plots over space-for-time substitutions

Back 72

No assumptions about habitat consistency needed.

Front 73

What are the drawbacks to permanent plots?

Back 73

Time, finding site again

Front 74

List four aspects of disturbance that will affect the course of succession.

Back 74

Pg. 9 Type, intensity, frequency, selectivity

Front 75

Discuss how facilitation, tolerance and inhibition may all be involved in a single succession.

Back 75

page. 6

Front 76

deflected vs. arrested development.

Back 76

Changes vs. stops

Front 77

Progressive vs. retrogressive succession

Back 77

Progressive: simple-->complex

Retrogressive: complex--> simple

Front 78

relay succession vs. initial floristic composition

Back 78

Clear stages vs. stages that are hard to recognize.

Front 79

amelioration and facilitation

Back 79

abiotic vs. biotic

Front 80

Colonization vs. establishment

Back 80

getting there vs staying

Front 81

Convergent vs. divergent trajectories

Back 81

similarity vs. differentiation

Front 82

Criticize Grime's trajectory diagrams.

Back 82

Deterministic fate not necessarily true, doesn’t separate out layers (lose details), very simplified (tradeoff)

Front 83

If you sample vegetation on Tiger Mountain and obtain very good environmental data (fertility, moisture), location data (elevation, distance from trail, roads, etc.), and know the time since major disturbance (e.g. burn or cut), will you necessarily be able to explain a high percentage of the variation?

Can you use a linear method of comparison?

Back 83

20% good, depends on if those factors are driving.

No, simplified

Front 84

Text books often show successional diagrams based on chronosequences. Discuss the pitfalls of this approach, as revealed by recent studies of dunes, bogs or old fields.

Back 84

Too many assumptions and oversimplifications.

Front 85

What factors have been of particular importance to primary succession on Surtsey?

Back 85

Bird poop, water dispersal to some extent, a bit of wind, safe-sites

Front 86

Wetlands usually display hydric soils, hydrophytic vegetation, and wetland hydrology. For each parameter, list one observation that would satisfy the requirement of a positive finding of wetland conditions.

Back 86

1. Black, organic matter, mottling. 2. Fac, fac wet, obliate at least 20% each and 50% overall 3. Saturated 2 weeks of growing season

Front 87

What are the main values and functions of wetlands?

Back 87

Habitat for plants, fun, economically important, biofiltration, moderation of stream flow, breeding habitat for fish

Front 88

Swamp

Back 88

-Dominated by woody species
-Intermediate nutrient
-More acid
-Intermediate between bog and tidal marsh

Front 89

Marshes (deep and shallow)

Back 89

-Dominated by herbs, ermergent cattails
-Deep: Up to 6 feet with rooted floating aquatics
-Shallow: up to 15 cm water
-High nutrients
-High water fluctuation

Front 90

Bogs

Back 90

-Dominated by herbs, mosses
-Limited soil oxygen
-Decomposition limited
-More acidic than fen
-High water fluctuation

Front 91

Fens

Back 91

-Dominated by herbs
-Limited soil oxygen
-Decomposition limited
-Less acidic than bog
-Alkaline
-Low nutrients
-Low water fluctuation

Front 92

Wet Meadow

Back 92

-Seasonally dry
-Often dry part of year
-Frequently grazed
-Not considered wetlands by land owners

Front 93

Scrub-shrub wetland

Back 93

-Dominated by woody shrubs

Front 94

What is a wetland class? Why is it important to know the wetland class when you are delineating a wetland for regulatory purposes?

Back 94

Different protection, importance, function

Front 95

Describe expected results from a selective removal experiment conducted in
a productive meadow and contrast the potential result with the same type of
experiment conducted in a dry, infertile meadow.

Back 95

In the more productive meadow it would be quicker for other
species to take over and it might be different species that take over the area
if it was a competitor that was removed.

In the infertile meadow the same species would probably return because it is one of the few adapted to the area and it would take longer for this to happen.

Front 96

By what 3 fundamental strategies do plants compete?

Back 96

pre-emption, tolerance, efficiency, avoidance, regeneration niches, safe-sites, allelopathy, interference