FWF 410:
“What is Habitat?”
Matthew J. Gray, Ph.D.
College of Agricultural Sciences and
Natural Resources
University of Tennessee-Knoxville
Goal of the Lecture
To familiarize students with
standardized definitions of “habitat”
and other “habitat-related” terms.
Reading Assignments:
1) Hall et al. (1997). The habitat concept and a plea for
standard terminology. Wildlife Society Bulletin 25:173−182.
Lecture Structure
I.
What are your examples of habitat?
II. What are your definitions of habitat?
III. Habitat definition and components
IV. Other habitat terms
1
What do you Think?
Your Examples of Habitat
What do you Think?
Your Definition of Habitat
Habitat Paper
Hall, Krausman, and Morrison
Summary Statistics (n=50 papers)
Habitat Terms Misused Frequently!
•Only 9% used “habitat” and “related terms” correctly.
•Most commonly “habitat” and “habitat type” were
confused with “vegetation association” (89%, 94%)
•Most of the articles (82%) that used “habitat” or “related
terms” (e.g., habitat use, selection, preference, availability)
did not define them.
2
Habitat Definition
Hall et al. (1997)
Resources and conditions present in an area that produce occupancy
(including survival and reproduction) by an organism.
It is more than just vegetation!
(Abiotic & Biotic!)
And, habitat is organism specific!
(Terrestrial animals)
Correct Uses:
grouse habitat, amphibian habitat, wildlife habitat
Incorrect Uses:
grassland habitat, wetland habitat, forest habitat
early-successional habitat
Vegetation Associations for a Site
Correct: “a warm-season grassland” or “grassland vegetation”
or “early-successional vegetation”
Habitat Components
Abiotic and Biotic Factors
Biotic Factors:
1) Vegetation: food and cover (thermal, escape, breeding)
2) Other organisms: food and reproduction
Abiotic Factors:
3) Water: drink, food, absorption
What is necessary
for survival and
reproduction?
4) Ambient conditions: temperature relations
Spatial Structure: (location)
5) Proximity & Permeability
Note: Organism absence Y habitat absence.
Other Habitat Terms
Hall et al. (1997)
Habitat Type:
Daubenmire (1968)
The type of vegetation association in an area or at climax.
(e.g., oak-hickory habitat type)
Do not use “habitat type” terminology.
Habitat Use:
Oak-hickory
vegetation, forest,
or climax
The way an animal uses a collection of abiotic and biotic
resources to meet life-cycle needs of survival and reproduction.
Consumption and physical use.
3
Other Habitat Terms
Hall et al. (1997)
Habitat Selection: Hierarchical process involving a series of innate and learned
behavioral decisions made by an animal at different geographic
scales to determine a location to acquire resources in a habitat.
Ecology 61:65-71
Geographic Range
Home Range
Specific Sites
Macro-habitat
vs.
Micro-habitat
Acquiring Resources
Anim. Behav. 20:218-220
Habitat Preference: The process of habitat selection that results in disproportional
use of some biotic resources over others.
Use vs. Availability
Other Habitat Terms
Hall et al. (1997)
Habitat Availability: Accessibility and procurability of physical and biological
components of habitat.
Differs from abundance
Food not available
Food available
Low
Habitat Quality:
Medium
High
The ability of the environment to provide conditions sufficient for
survival and reproduction.
High densities ⇒ High quality habitat.
Source vs.
Sink
Measure: demographic parameters (survival, reproduction, fitness, dispersal)
Other Habitat Terms
Hall et al. (1997)
http://www.nwrc.usgs.gov/wdb/pub/hsi/hsiindex.htm
Habitat Suitability:
USGS HSI (Habitat Suitability Index) Models
By definition, habitat can support an organism thus it must
be suitable. Therefore, “unsuitable habitat” does not exist.
If it is habitat, then only its quality changes.
Use “Habitat Quality” instead of “Suitability”
2 Possibilities:
1)
Habitat
2) Non-Habitat
Sites that cannot support
an organism.
Occupied
Unoccupied
4