Some Basic Concepts

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Some Basic Concepts For Managing Land
Dr. Karl Wood, Director Water Resources Research
Institute Stucky Hall New Mexico State University
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Suppose you have just acquired some land!
Some questions need to be answered

• What is the climate?
• What is the topography?
• What plants and animals are present?
• What is the soil condition?
• What are the goals for land?
• What is it capable of growing?
• Are the goals ecologically, socially, and
  economically feasible?

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To answer these questions, some scientific
understanding is needed.
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Trophic Energy Pyramid Example
Tertiary Consumer Eagle 6 cal
heat
heat
Secondary Consumers Snake 60 cal Wolf
heat
Decomposers
Primary Consumers Mice 600 cal
Sheep
heat
Primary Producers Plants 6000 cal/m2/yr
Plants
Sunshine Water Minerals Nutrients
Based on Second Law of Thermodynamics
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Land Goal?

• Exploitation Sustainable Protection
• Use

The extremes result in attitudes of supremacy
From Thompson, P.B. 1995. The Spirit of the
Soil - Agriculture and Environmental
Ethics. Routledge Publ. New York, New York
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Concept of the Sere
Example developed in North America by H.C. Cowles
and F.E. Clements about 100 years ago
Climate
Lichens
Bare Rock
Soil depth and richness
Time
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Example of a lichen associated animals
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Concept of the Sere
Climate
Mosses
Lichens
Bare Rock
Soil depth and richness
Time
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Example of a moss associated animals
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Concept of the Sere
Annual grasses and forbs
Climate
Mosses
Lichens
Bare Rock
Soil depth and richness
Time
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Example of annual grasses and forbs associated
animals
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Concept of the Sere
Perennial grasses and forbs
Annual grasses and forbs
Climate
Mosses
Lichens
Bare Rock
Soil depth and richness
Time
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Examples of perennial grasses and forbs
associated animals
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Concept of the Sere
Shrubs
Perennial grasses and forbs
Annual grasses and forbs
Climate
Mosses
Lichens
Bare Rock
Soil depth and richness
Time
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Example of shrubs associated animals
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Concept of the Sere
Deciduous trees
Shrubs
Perennial grasses and forbs
Annual grasses and forbs
Climate
Mosses
Lichens
Bare Rock
Soil depth and richness
Time
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Example of deciduous trees
associated animals
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Concept of the Sere
Conifers
Deciduous trees
Shrubs
Perennial grasses and forbs
Annual grasses and forbs
Climate
Mosses
Lichens
Bare Rock
Soil depth and richness
Time
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Example of conifers growing through deciduous fo
rest
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Example of conifers associated animals
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Concept of the Sere
Each level Is called a seral stage
Climax
Conifers
Deciduous trees
Shrubs
Perennial grasses and forbs
Climate
Annual grasses and forbs
Mosses
Lichens
Bare Rock
Soil depth and richness
Time
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Concept of the Sere
Climax
Conifers
Deciduous trees
Primary Succession
Shrubs
Perennial grasses and forbs
Climate
Retrogression
Secondary succession
Annual grasses and forbs
Mosses
Lichens
Bare Rock
Soil depth and richness
Time
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General Comments On Ecosystem Succession

• Movement towards climax is called succession

• Movement away from climax is called
  retrogression (e.g. Desertification)

• The kinds of animals are different in each
  seral stage.

• The climax seral stage usually does not
  represent the greatest species diversity of
  plants and animals.

• Subclimax seral stages may be maintained by
  continuous or discontinuous perturbations such
  as fire, grazing, hurricanes, etc.

• Multiple equilibrium communities and complex
  successional pathways may be possible within a
  sere.

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To manage an ecosystem, managers need to know
1. What is the potential or climax seral stage
of the area?
2. What is the present seral stage of the area?

• Is it all the same or are there different
  seral stages in different parts of the area?

3. Are there several acceptable seral stages
and a preferred seral stage of the area and/or
its parts?
4. Can the preferred seral stage be achieved
with the present technology, time, legal,
political, and economic constraints?
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Concept of the Sere
Conifers Deciduous trees
Shrubs Perennial grasses and forbs
Most choices are here!
Climate
Annuals
Mosses
Lichens
Bare Rock
Soil depth and richness
Time
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Concept of the Sere
What seral stage Has the most Plant and
animal Diversity?
Conifers Deciduous trees
Shrubs Perennial grasses and forbs
Climate
Annuals
Mosses
Lichens
Bare Rock
Soil depth and richness
Time
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Diversity (number of plant animal Species)
Bare Rock
Seral Stage
Climax
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Concept of the Sere
Can the Seral stage Ever be above Climax?
Conifers Deciduous trees
Shrubs Perennial grasses and forbs
Climate
Annuals
Mosses
Lichens
Bare Rock
Soil depth and richness
Time
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Concept of the Sere
Example
(Pecan orchard)
Yes!
Deciduous trees
Artifical inputs of water and nutrients
(Fertilizer)
Perennial grasses and forbs
(Desert grasslands)
Climate
Annuals
Mosses
Must have adequate soil depth!
Lichens
Bare Rock
Soil depth and richness
Time
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Concept of the Sere
When retrogression occurs, increased erosion
rates can be expected.
Example
Native Great Plains
Perennial grasses and forbs
Annual grasses and forbs
Converted to cropland (corn, soybeans, wheat,
cotton)
Climate
Mosses
Lichens
Bare Rock
Soil depth and richness
Time
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Conclusions
Nature abhors a void
Nature abhors topographical prominence
Nature abhors a crowd
Natural changes are often dynamic and
catastrophic with unpleasant consequences for
humans
Changes in nature due to human activities may be
dynamic and catastrophic, or static, controlled,
predictable, and beneficial to humans, animals,
and the land where they live.
Human influence is most probable for avoiding
catastrophes and assuring ecological, social, and
economic stability.
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Conclusions
Healthy Land preferred seral state is
attained
Sustainability preferred seral stage is
maintained against the processes of succession
and retrogression, including invasions,
especially by exotics
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God bless America!
And Pistol Pete!
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Thank you!
Thank you!