SAMPLING VEGETATION ATTRIBUTES - New Mexico NRCS - US ...

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METHODS—Daubenmire b Ten Cover Classes Where narrower and more numerous classes are preferred, a ten-cover class system can be used. c Collecting Cover Data As the quadrat frame is placed along the tape at the specified intervals, estimate the canopy coverage of each plant species. Record the data by quadrat, by species, and by cover class on the Daubenmire form (see Illustration 9). Canopy coverage estimates can be made for both perennial and annual plant species. (1) Observe the quadrat frame from directly above and estimate the cover class for all individuals of a plant species in the quadrat as a unit. All other kinds of plants are ignored as each plant species is considered separately. (2) Imagine a line drawn about the leaf tips of the undisturbed canopies (ignoring inflorescence) and project these polygonal images onto the ground. This projection is considered “canopy coverage.” Decide which of the classes the canopy coverage of the species falls into and record on the form. (3) Canopies extending over the quadrat are estimated even if the plants are not rooted in the quadrat. (4) Collect the data at a time of maximum growth of the key species. (5) For tiny annuals, it is helpful to estimate the number of individuals that would be required to fill 5% of the frame (the 71- x 71-mm area). A quick estimate of the numbers of individuals in each frame will then provide an estimate as to whether the aggregate coverage falls in Class 1 or 2, etc. (6) Overlapping canopy cover is included in the cover estimates by species; therefore, total cover may exceed 100 percent. Total cover may not reflect actual ground cover. 9. Calculations Make the calculations and record the results in the appropriate columns on the Daubenmire form (see Illustrations 9 and 10). a Canopy Cover Calculate the percent canopy cover by species as follows: (1) On the Daubenmire form (Illustration 9) count the number of quadrats in each of the six cover class (by species) and record in the Number column on the Daubenmire Summary form (Illustration 10). (2) Multiply this value times the midpoint of the appropriate cover class (Illustration 10). (3) Total the products for all cover classes by species. (4) Divide the sum by the total number of quadrats sampled on the transect. (5) Record the percent cover by species on the form. 57
58 METHODS—Daubenmire b Frequency Calculate the percent frequency for each plant species by dividing the number of occurrences of a plant species (the number of quadrats in which a plant species was observed) by the total number of quadrats sampled along the transect. Multiply the resulting value by 100. Record the percent frequency on the form (Illustration 10). c Species Composition With this method, species composition is based on canopy cover of the various species. It is determined by dividing the percent canopy cover of each plant species by the total canopy cover of all plant species. Record the percent composition on the form (Illustration 10). 10. Data Analysis Tests should be directed at detecting changes in cover of the species and/or in major ground cover classes. Tests for changes in minor species will have low power to detect change. If quadrats are spaced far enough apart on each transect so as to be considered independent, the quadrat can be analyzed as the sampling unit. Otherwise, the transects should be considered the sampling units. If the transects are treated as the sampling unit, and given that the transects are permanent, either the paired t-test or the nonparametric Wilcoxon signed rank test should be used to test for change between two years. Repeated measures ANOVA can be used to test for differences between 3 or more years. If the quadrats are treated as the sampling units, care must be taken to ensure they are positioned the same along each transect in each year of measurement. A paired t-test, Wilcoxon signed rank test, or ANOVA is then used as described above for transects. 11. References Daubenmire, Rexford. 1959. A Canopy-coverage method of vegetational analysis. Northwest Science 33:43-64. ——— 1968. Plant communities: a textbook of plant synecology. Harper and Row, <strong>New</strong> York. 300 p. <strong>US</strong>DI, Bureau of Land Management. 1985. Rangeland monitoring - Trend Studies TR4400-4.
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SAMPLING VEGETATION ATTRIBUTES INTE
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TABLE OF CONTENTS SAMPLING VEGETATI
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TABLE OF CONTENTS TABLE OF CONTENTS
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I. PREFACE PREFACE The intent of th
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2 INTRODUCTION values when individu
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4 INTRODUCTION represent the “pul
Page 13 and 14: 6 INTRODUCTION G. Coordination Moni
Page 15 and 16: 8 STUDY DESIGN AND ANALYSIS A. Plan
Page 17 and 18: 10 STUDY DESIGN AND ANALYSIS Macrop
Page 19 and 20: 12 STUDY DESIGN AND ANALYSIS Becaus
Page 21 and 22: 14 STUDY DESIGN AND ANALYSIS d From
Page 23 and 24: 16 STUDY DESIGN AND ANALYSIS b Cove
Page 25 and 26: 18 STUDY DESIGN AND ANALYSIS sideoa
Page 27 and 28: 4 3.5 3 2.5 20 5 STUDY DESIGN AND A
Page 29 and 30: 22 STUDY DESIGN AND ANALYSIS C. Oth
Page 31 and 32: 24 ATTRIBUTES Frequency is the numb
Page 33 and 34: 26 ATTRIBUTES 2. Advantages and Lim
Page 35 and 36: 28 ATTRIBUTES b Standing crop and p
Page 37 and 38: 30 ATTRIBUTES
Page 39 and 40: 32 METHODS—Photographs c Angle ir
Page 41 and 42: METHODS—Photographs Hinge Rod sta
Page 43 and 44: METHODS—Photographs angle iron st
Page 45 and 46: 38 METHODS—Frequency • One tran
Page 47 and 48: 40 METHODS—Frequency transected,
Page 49 and 50: 42 METHODS—Frequency (3) Total fr
Page 51: Page of Frequency 44 Study Number D
Page 55 and 56: METHODS—Frequency The frame is ma
Page 57 and 58: 50 METHODS—Dry Weight Rank C. Dry
Page 59 and 60: 52 METHODS—Dry Weight Rank After
Page 62 and 63: D. Daubenmire Method METHODS—Daub
Page 66: Page of Daubenmire Study Number Dat
Page 70 and 71: 50 cm Six Cover Class Frame 20 cm R
Page 72 and 73: METHODS—Line Intercept b Pilot St
Page 74 and 75: METHODS—Line Intercept Hanley, Th
Page 77 and 78: 70 METHODS—Step Point F. Step-Poi
Page 79 and 80: 72 METHODS—Step Point the boot an
Page 81 and 82: 74 METHODS—Step Point measures AN
Page 85 and 86: 78 METHODS—Point Intercept G. Poi
Page 87 and 88: 80 METHODS—Point Intercept 8. Sam
Page 89 and 90: 82 METHODS—Point Intercept b Tran
Page 91 and 92: METHODS—Point Intercept Examples
Page 93 and 94: 86 METHODS—Cover Board H. Cover B
Page 95 and 96: 88 METHODS—Cover Board g Study Do
Page 98: Page of Cover Board Method Profile
Page 101 and 102: 94 METHODS—Density I. Density Met
Page 103 and 104: 96 METHODS—Density (often very mu
Page 105 and 106: 98 METHODS—Density able to make s
Page 107: Page of Density Study Number Date E
Page 110 and 111: • Herbage Yield Tables for Trees
Page 112 and 113: METHODS—Double Weight Sampling (4
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METHODS—Double Weight Sampling d
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Page of Production Study Number Dat
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112 METHODS—Harvest K. Harvest Me
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114 METHODS—Harvest 7. Taking Pho
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116 METHODS—Comparative Yield L.
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118 METHODS—Comparative Yield (1)
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120 METHODS—Comparative Yield Tab
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M. Visual Obstruction Method - Robe
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METHODS—Visual Obstruction—Robe
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Sampling Interval Study Location 1
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130 METHODS—Other N. Other Method
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132 GLOSSARY browse: (1) the part o
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134 GLOSSARY grazable woodland: for
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136 GLOSSARY sample: a set of sampl
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138 GLOSSARY
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140 REFERENCES Crocker, R.L. and N.
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142 REFERENCES Hironaka, M. 1985. F
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144 REFERENCES Nie, Norman H., C. H
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146 REFERENCES Society for Range Ma
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148 REFERENCES Whitman, W.C. and E.
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Location 150 APPENDIX A Study Locat
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APPENDIX B APPENDIX B—STUDY AND P
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APPENDIX B 3. Label 3 A placard on
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APPENDIX C Photo Identification Lab
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160 APPENDIX C
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162 APPENDIX D The formula for usin
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Form Approved OMB No. 0704-0188 Pub
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