Saltcedar, an exotic weed of western North American riparian areas : a review of its taxonomy, biology, harmful and beneficial values, and its potential for biological control

466 Pages·1991·29.6 MB·English

by  DeLoach, C. Jack

Historic, Archive Document
Do not assume content reflects current
scientific knowledge, policies, or practices.

Reserve
aQK495
.T35D45
1991
Saltcedar, An Exotic Weed of Western North American Riparian Areas:
A Review of Its Taxonomy, Biology, Harmful and Beneficial Values, and
Its Potential for Biological Control
Submitted by C. Jack Deloach
Grassland, Soil and Water Research Laboratory
U.S. Department of Agriculture
Agricultural Research Service
808 East Blackland Road
Temple, Texas 76502
£ M
f' i
January 1991
FINAL REPORT
(Volume 1 of 2)
In fulfillment of
U.S. Bureau of Reclamation
Contract No. 7-AG-30-04930
. USDA National Agricultural Library
NAL Building
10301 Baltimore Bivd.
Beltsville, MD 20705-2351
United States
Department of
Agriculture
LIST V
LIS1 xl
PREf xlv
EXEI 1
II. INTI 9
n
III. TAXONOMY OF SALTCEUAK
IV. SPREAD AND ABUNDANCE OF SALTCEDAR IN THE U.S. 22
V. BIOLOGY AND ECOLOGY . 26
A. Growth Form . 26
B. Flowers . 28
C. Seeds . 29
D. Germination and Establishment . 29
E. Leaves . 31
F. Roots . 32
G. Inundation and Desiccation Stress . 34
H. Salt . 35
I. Secondary Chemical Compounds . 36
VI. DISPLACEMENT OF NATIVE VEGETATION . 37
A. Historical Perspective and Present Status . 37
1. Lower Colorado River . 38
2. Gila River . 43
3. Rio Grande . 46
4. Brazos River, TX . 47
5. Other Regions . 48
B. Causes of Riparian Habitat Degradation . 48
1. Livestock Overgrazing . 52
2. Clearing for Agriculture . 54
3. Cutting for Firewood, Charcoal, Construction, etc. 55
4. Dams for Flood Control and Irrigation . 56
5. Urbanization, Housing Developments and
Recreation, etc. 58
6. Pumping Groundwater . 59
7. Phreatophyte Control and Channelization . 59
8. Fire . 61
9. Exotic Plant Invasions . 62
C. Effects of Habitat Degradation on Wildlife . 62
D. Prevention of Habitat Degradation and Reclamation of
Degraded Areas . 65
1. Land Acquisition for Wildlife Habitat . 65
i
\
2. Revegetation of Saltcedar^cleared Riparian Areas . 67
a. Examples of revegetation projects . 68
b. Effects of wildlife enhancement . 74
c. Factors Influencing success . 75
1. Species of plants used .... 75
2. Depth to groundwater . 77
3. Soil salinity . 78
4. Soil type . 79
5. Irrigation . 79
6. Damage from weeds, Insects, wildlife and
livestock . 80
7. Summary - Criteria for success . 80
d. Monitoring . 82
e. Costs of revegetation . 82
3. Management of Riparian Areas within Public Lands . 84
4. Mitigation . 85
5. Control of Harmful Exotic Plant Invaders . 85
E. Effects of Saltcedar in Parks and Other Protected Areas ... 87
1. Tiernan Survey . 87
3. Tucson Symposium . 91
2. Brown Survey . 93
F. Impact of Biological Control on the Riparian
Plant Community . 95
G. Conclusions . 98
VII. EFFECTS OF SALTCEDAR ON WILDLIFE . 101
A. Non-Game Birds . 101
1. Value of Riparian vs. Other Areas . 101
2. Birds of the Lower Colorado River, Arizona
and California .. 103
3. The Middle Rio Grande River Valley . 113
4. The Middle Pecos River Valley . 117
5. Sonora, Mexico . 125
6. Comparisons of Different River Valleys . 126
B. Terrestrial Vertebrates . 127
1 . Small Mammals ... 127
2. Reptiles and Amphibians . 130
C. Damage Caused by Saltcedar to Non-consumptive Wildlife
Use ("Bird Watching" etc.) . 132
D. Game Birds - The White-winged Dove . 141
1. Taxonomy and Distribution . 142
2. Habitat Selection - Eastern Area . 145
3. Habitat Selection - Western and Trans-Pecos
Texas Areas . 146
4. Habitat Selection - Northwestern Mexico . 155
5. Migration and Annual Cycle . 157
6. Nesting . 160
7. Feeding . 162
i i
8. Mortality and Hatura 1 Enemies ..... . 164
9. Populations and Hunting - Eastern Area . 167
a. Methods of estimating population and hunting . 167
b. Populations and hunting - Eastern area . 169
10. Populations and Hunting - Western Area . 173
11. Economic and Social Characteristics of Hunters
and Hunting In Texas and Mexico . 178
E. Game Birds - Mourning Dove . 184
F. Game Birds - Gambel's Quail . 191
G. Other Game Animals and Birds . 195
H. Fishes . 199
I. Drinking Water for Wildlife . 201
J. Impacts of Biological Control on Wildlife . 201
1. White-winged and Mourning Dove Hunting . 202
2. Wildlife Ecological Values . 203
VIII. USE OF WATER BY SALTCEDAR . 206
A. Introduction . 206
1. Historical Perspective . 206
2, Politico-Administrative Agreements . 207
a. Lower Colorado River Basin . 207
b. Pecos River Basin . 207
c. Research and control planning and coordination .... 208
B. Methodology of Measuring Water Usage by
Phreatophytic Plants . 209
C. Measurements in Lysimeter or Evapotranspiration Tanks . 212
1. Early Studies in California . 214
2. Pecos River near Carlsbad, NM . 214
3. Gila River near Safford, AZ . 215
4. Gila River near Buckeye, AZ . 221
a. Facilities . 221
b. Water usage . 222
c. Effects of salinity on water usage . 222
d. Effects of plant density . 226
e. Diurnal and seasonal fluctuations . 227
5. Rio Grande near Bernardo, NM . 229
a. Early studies . 229
b. Large lysimeter studies: 1960's . 230
D. Transpiration Wells . 236
E. Inflow-Outflow Method . 239
F. Other Methods of Measurement . 241
1 . Seepage-run . 241
2. Slope-seepage . 242
3. Chloride-increase .. 243
G. Evapotranspiration Tent Method . 243
H. Empirical Equations . 245
I. Mlcrometerologlcal Methods .....
1. Vapor-flow Methods . 248
a. Atmospheric-water-balance method .
248
b. Eddy-correlation method .
248
c. Bulk aerodynamic (or mass-transfer) method 249
2. Energy-budget (or Energy-balance) Method . 249
a. Studies by van Hylckama . 250
b. Studies by Gay and coworkers . 253
.
3 Water Stress - Diurnal Pattern of Usage . 260
K. Water Usage Before and After Clearing Phreatophytes 264
1. Gila River Phreatophyte Project, San Carlos, AZ 264
2. Pecos River Studies. 269
3. Other Studies . 272
L. Discussion, Economics, and Effects of
Biological Control on Water Usage . 274
IX. SEDIMENTATION, FLOODING AND SOIL SALINITY . 283
A. Sedimentation and Flooding . 283
B. Economic Effects of Saltcedar Control on Flooding . 286
C. Economic Effects of Saltcedar Control on Sedimentation _ 288
D. Soi 1 Salinity ..... 289
X. LIVESTOCK FORAGE: COMPETITION FROM SALTCEDAR . 291
XI. OTHER HARMFUL VALUES . 295
XII. VALUE FOR HONEYBEES . 296
XIII. VALUE OF SALTCEDAR FOR ORNAMENTALS . 306
A. In Texas . 306
B. In Arizona and Neighboring States . 308
XIV. WINDBREAKS, SOIL STABILIZATION AND OTHER USES . 313
XV. USAGE IN MEXICO . 315
XVI. NATURAL ENEMIES OF SALTCEDAR . 319
A. In North America . 319
B. In Other Areas of the World . 321
1. In Israel, Turkey, Iran and India . 321
2. In Pakistan . 327
XVII. NON-BIOLOGICAL CONTROLS . 338
A. Herbicidal Controls . 339
1. Herbicides that Can Be Used to Control Saltcedar . 339
2. Herbicides Previously Used but Now Prohibited . 347
3. Past Experience in Herbicidal Control of Saltcedar . 348
i v
B. Non-Chemical Controls . 352
1. Mowing and Chaining . 352
2. Root Plowing . 353
3. Combination Mechanical and Chemical Controls . 353
4. Burning . 353
5. Desiccation . 354
6. Inundation . 355
C. Cost of Controls . 355
D. Conclusions . 356
XVIII. BIOLOGICAL CONTROL . 360
A. Philosophy and History . 360
B. Potential for Biological Control of Saltcedar . 363
C. Procedures for Implementing Biological Control
of Saltcedar . 364
XIX. ECONOMIC ANALYSIS . 367
A. Economic Account . 368
B. Environmental Account . 369
C. Social Well-being Account . 373
D. Summary of Accounts . 378
XX. SUMMARY . 382
XXI. LITERATURE CITED . 409
v
LIST OF TABLES
Table no. Table title Page no.
1 Vegetative composition of various riparian areas of 41
which detailed measurements have been made
2 Classification of vegetative along the Lower Colorado 42
River from Davis Dam to the U.S.-Mexican border
3 Vegetation of the Brazos River and major tributaries In 49
northwestern Texas
4 Changes in vegetative composition of the floodplain of 50
the Brazos River, TX, 1940-1969
5 Land acquired for wildlife habitat in Texas 66
6 Plantings, results and costs of 17 revegetation projects 71
along the Lower Colorado River
7 Costs of revegetation of two representative sites on the 83
Lower Colorado River
8 Total areas of riparian vegetation along the Colorado 106
River, AZ and CA, from Davis Dam to the Mexican border
9 Comparison of total densities (number per 40 ha) and 108
number of species of birds in 4 plant community types
in the Lower Colorado River Valley, December 1975-
November 1976
10 Patterns of vegetation use by avian groups on the 109
Lower Colorado River
11 Species composition of the plant communities on the 114
Rio Grande of western Texas
12 Habitat breadths of birds in the Rio Grande Valley, NM 116
13 Pecos River Valley community and structural types 118
14 Mean tree and shrub counts (number per 0.23 ha) for 119
each community/structural type
15 Number of species of birds in 14 community/structural 122
types of riparian vegetation by seasons, in the Middle
Pecos River Valley, September 1979 to May 1981
Table no. Table title Page no.
16 Density of birds in 14 community/structural types in 123
the Middle Pecos River riparian area by seasons,
September 1979 to May 1981
17 Numbers of bird species showing clear preference and 127
mean population of all birds per unit area for different
plant communities on three western rivers
18 Habitat preference of rodents in the Lower Colorado 129
River Valley, 1974-1979
19 Habitat preference for rodents in the Rio Grande Valley 129
of western Texas
20 Lizard densities along the Colorado River in Grand 131
Canyon, summer 1984
21 Calculation of the value of non-consumptive use of 134
wildlife (observing, feeding, photographing) in riparian
areas
22 Expenditures for fishing, hunting and non-consumptive 135
usage of wildlife in the U.S., 1985
23 Consumptive usage (hunting and fishing): number of 136
participants, days of activity, and expenditures in
1985
24 Non-consumptive usage (hunting and fishing): number 137
of participants, days of activity, and expenditures
in 1985
25 Allocation of primary non-consumptive usage of wildlife 138
to non-residential or residential usage
26 Breeding density estimates for various habitat types, 147
Arizona, 1963
27 Habitat types used by the white winged dove in Arizona 149
28 Density of the whitewinged dove from May through 151
September in various community/structural vegetational
types in the Lower Colorado River Valley, 1975-77
29 Reproduction and mortality of the white-winged dove in 151
three riparian communities on the Lower Colorado River
VI 1