Disturbance and Succession

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Disturbance and Succession
I. Definitions Disturbance any relatively
discrete event in time that disrupts ecosystem,
community, or population structure and changes
resource availability, or the physical
environment (Pickett and White 1985) - a
delineated event that causes mortality
(Valett, today)
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Disturbance and Succession
I. Definitions Perturbation - any change in a
parameter that defines a system (Pickett and
White 1985) - i) control parameters defined -
ii) new disturbance - iii) disturbance under
user control
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Disturbance and Succession
I. Definitions Succession change in community
structure following a disturbance that is driven
by the endogenous processes of facilitation,
inhibition, and tolerance
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Disturbance and Succession
I. Definitions Disturbance Regime the
combined spatial and temporal aspects
characterizing disturbance occurrences for a
given ecosystem
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Components of a Disturbance Regime
1) frequency 2) duration 3) extent 4) intensity
From Pickett and White (1985)
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II. Measures of Disturbance and Responses 1)
resistance the tendency for a state variable to
retain its value as measured across a
disturbance 2) resilience the capacity for a
state variable to return to a pre-disturbance
value 3) persistance the extent to which
species remain as part of a give community
following disturbance (i.e., change in S) 4)
constancy the extent of variation
characteristic of any given variable
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Disturbance and Succession
III. Ecosystem Succession 1) definition
change in ecosystem structure and function
following a disturbance
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2) The Theory of Ecosystem Development (Odum
1969) energetics, nutrients, and stability
A) energetics
NPP
Biomass (B)
GPP R Biomass (B)
GPP
R
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The Theory of Ecosystem Development (Odum
1969) energetics, nutrients, and stability
B) Nutrient Cyles i) closing of nutrient
cycles ii) the cycling index (CI) C)
Stability i) decline in resilience ii) increase
in resistance
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3) Nutrient Retention and Succession a
hypothesis
From Vitousek and Reiners (1975)
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4) biomass accumulation model Shifting mosaic
steady state
Ecosystem succession in a hardwood forest
From Borman and Likens (1979)
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IV) Disturbance and Ecosystem Succession in a
Desert Stream Ecosystem Sycamore Creek, AZ
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Sycamore Creek, AZ A) flash flooding ecosystem d
isturbance
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1) community responses algal diversity
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1) community responses invertebrate diversity
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C) Ecosystem Responses
Biomass and Chlorophyll
Algal Patches
From Fisher et al. (1982)
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Ecosystem Succession in a Desert Stream
Invertebrate Food
From Fisher et al. (1982)
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Ecosystem Succession in a Desert Stream
Ecosystem Metabolism
From Fisher et al. (1982)
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Ecosystem Succession in a Desert Stream
Production to Biomass Ratios
From Fisher et al. (1982)
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Ecosystem Succession in a Desert Stream
Net Production (PN) and Net Biomass
Increment (NBI)
From Fisher et al. (1982)
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D) Nutrient Retention and Succesion Test of a
Hypothesis in a Desert Stream
From Grimm (1987)
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V) Aquatic-Terrestrial Linkage and Ecosystem
Succession in a Forested Stream 1) Fire,
wood, and invertebrate biomass
From Molles (1982)
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2) Logging, wood, and nutrient retention
Debris dams
Fine sediments
Normalized storage
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Borman and Likens 1979
Vitousek and Reiners 1975
Webster et al 1995
Valett et al. 2002