Defining A Healthy Riparian Area Dr. Karl Wood, Director Water Resources Research Institute Dr. Terrell Baker, Riparian Ecologist New Mexico State University Las Cruces, NM
Dec 20, 2015
Defining A Healthy Riparian Area
Dr. Karl Wood, DirectorWater Resources Research Institute
Dr. Terrell Baker, Riparian EcologistNew Mexico State University
Las Cruces, NM
Webster’s Definition of “Health”
1. Physical and mental well-being;
2. Soundness;
3. Freedom from defect, pain, or disease;
4. Normality of mental and physical functions
How does this definition apply to riparian areas?
What are some other terms or phrases used to describe watersheds?
Sustainable
Functioning and Non-Functioning
Proper Functioning Condition
Impaired
Stable
Upward Trend
At Risk
Downward Trend
Rangeland Health (Natural Research Council 1994)“The degree to which the integrity of the soil and ecological processes of rangeland ecosystems are maintained”
Forest Health (U.S. Forest Service)“A condition wherein a forest has the capacity across the landscape for renewal, for recovery from a wide range of disturbances, and for retention of ecological resiliency, while meeting current and future needs of people for desired levels of values, uses, products, and services”
Some Related Definitions
Riparian Health (Need Citation)“” Feds have some 70 plus definitions
Compare to Wetlands
• Lots of science
• Tight definition (at least comparatively)
• Regulatory authority
1. They convey that everything is either right or wrong.
2. They infer that nature gives values to society.
3. They also infer that society’s values are mutual across all lands,
both public and private
Why this vision of everything being black or white,
and why are these definitions bothersome?
Most people have an intuitive idea of what constitutes a healthy riparian area; at least, they believe they can recognize an unhealthy one
when they see it.
Using “health” to describe watersheds is probably inappropriate.
Riparian Conditions Fall Along
A Continuum!
How can we express that continuum?
Ecosystem Succession or the Sere is a good start!
Concept of the Sere
Bare Rock
LichensMosses
Soil depth and richness
ClimateAnnuals
Perennial grasses and forbsShrubs
Deciduous trees
Conifers Climax
Time
Example developed in North America by H.C. Cowles and F.E. Clements about 100 years ago
Conifer invasionof a meadow
Early ponderosa pine savanna
Ponderosa pine thicket today
Insects and disease spread in a crowded forest
Concept of the Sere
Bare Rock
LichensMosses
Soil depth and richness
ClimateAnnuals
Perennial grasses and forbsShrubs Climax
Time
Concept of the Sere
Bare Rock
LichensMosses
Soil depth and richness
ClimateAnnuals
Perennial grasses and forbs Climax
Time
Concept of the Sere
Bare Rock
Lichens
Soil depth and richness
Climate
Climax
Time
Would A Society Ever Want To Maintain Bare Rock
Or a Very Low Seral StageRiparian Area?
Example: Irrigation Ditches
• The kinds of animals 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.
• Movement towards climax is called succession
• Movement away from climax is called retrogression (e.g. Desertification)
• Multiple equilibrium communities and complex successional pathways may be possible within a sere.
General Comments On Ecosystem Succession
Explanations of “ecosystem succession” have been modified and expanded by:
Gleason 1926 – recognized individual species differencesTansley 1935 – proposed more than one climax for a siteWatt 1947 - identified the importance of patches and disturbance cyclesEgler 1954 – noted that species did not always invade but were present and
increased Pickett 1976 – recognized importance of natural selection and disturbanceConnell and Slatyer 1977 – proposed facilitation, tolerance, and inhibitionGrime 1979 – proposed ruderal, competitive, and stress-tolerant stagesHuston and Smith 1987 – demonstrate 5 successional patterns: sequential succession, divergence, total suppression, convergence, and pseudo-cyclic replacementShugart 1984 – claimed mechanistic rather than deterministic processesWestoby 1989 – explained state-and-transition models or thresholdsOliver and Larson 1990 – allowed for chaotic or non-equilibrium cycles
To manage a riparian area, managers need to know:
1. What is the potential or climax seral stage of the riparian area?
2. What is the present seral stage of the riparian area?
• Is it all the same or are there different seral stages in different parts of the riparian area?
4. Can the preferred seral stage be achieved with the present technology, time, legal, political, and economic constraints?
3. Are there several acceptable seral stages and a preferred seral stage of the riparian area
and/or its parts?
Concept of the Sere
Bare Rock
LichensMosses
Soil depth and richness
ClimateAnnuals
Perennial grasses and forbsShrubs
Deciduous trees
Conifers
Time
Mostchoicesare here!
If on the other hand the prime objective is watersheds, we should restore grass, which all the evidence indicates is a better watershed cover than either brush or woodland.”
Aldo Leopold
“If the prime objective is wood products, we may continue to overgraze, letting in the woodland and sacrificing watershed values.
Steps for Watershed Management
Preliminary Assessment and Surveillance
Preliminary Assessments and Surveillance
“Nothing in nature is isolated. Nothing is without reference to something else. Nothing achieves meaning apart from that which neighbors it.”
Johann Wolfgang von Goethe
“There is something fascinating about studies of science. One gets such wholesale returns of conjecture out of such trifling investment of fact.”
Mark Twain
Steps for Watershed Management
Preliminary Assessment and Surveillance
Goal Setting
Prioritization and Targeting
Watershed Planning – develop document with roles and implementation strategy
Implementation
Performance evaluation
For any given response variable such as: Erosion, Runoff, Evaporation,
Stream Temperature, Sediment Load, Arsenic Content, Plant Growth, Insect Populations, etc.
Questions should be asked:1. What are the natural levels with variations between hours,
days, months, and years?
2. What are maximum potential levels?
3. What are the tolerable levels to sustain the preferred seral stage?
4. What are the desirable levels?
5. Are the desirable levels achievable with present technology, time, legal, political, and economic constraints?
Nature abhors a void
Nature abhors topographical prominence
Nature abhors a crowd
Natural changes are often dynamic and catastrophic with unpleasant consequences for humans
Human changes of nature may be dynamic and catastrophic, or static, controlled, predictable, and
beneficial to humans, wildlife, and watersheds
Human influence is most probable for avoiding catastrophes and assuring ecological,
social, and economic stability.
Conclusions
A Healthy Watershed = preferred seral state is attained
Sustainability = preferred seral stage is maintained against the processes of succession and
retrogression, including invasions, especially by exotics
Conclusions
God bless America!
Thank you!
Thank you!