Rangeland Assessment

Determine if / what management is needed:

three questions:

Are adequate numbers and types of plants present?

Is herbaceous production suitable for the site?

Does forest, brush, or weed management need to be applied?

“Generally, seeding will not be done when 15% composition by weight of the desirable plants are _____

present, are well distributed over the treated area, and can be managed to a stand within an acceptable time frame.” – NRCS Range Planting Code 550.

_______: line or path along which observations are recorded

transect

_______: a plot of a defined area, usually rectangular or square

Quadrat

_______: paper or electronic forms used to record and organize data

datasheets

______: abundance and distribution of species; how often it is encountered

Measures presence vs. absence; quantifies presence

frequency

Nested frequency

Dry-weight-rank

Quadrats or plots (Daubenmire or larger)

methods of measuring frequency

Species A occurs % of the time; species B occurs % of the time, etc.

example of frequency

_______: how much of the ground / soil surface is covered by a species / functional group

cover

10-point frames

Single point sampling

Step-point

Daubenmire quadrats

line-intercepts

methods of measuring cover

______: Uses a single-size quadrat to estimate species cover

Procedure:

• Place quadrat at specified intervals along transect

• Estimate % of quadrat filled by each species present

• Cover estimates may be grouped into “classes” or left as raw estimates

Raw estimates - exact %

• Example: 52% grass, 19% forbs, 26% litter, 3% bare ground

Daubenmire Quadrats

______: Uses measurements along a transect to quantify cover of individual species

Commonly used to measure cover of trees and shrubs

• Easy to do this in areas where woody plants are a minor component

• Time consuming with multiple species and canopy layers

Procedure:

• Record distances along transect that are occupied by canopies of species of interest

• Ex. 50 meter transect with shrub coverage at 10-15 meters (5m), 18-21 meters (3m), 38-45 meters (7m) = 30% coverage

Specifically:

• Only record where the canopy covers the transect line

• Place the transect under shrubs and between stems of multi-stemmed shrubs

  • You shouldn’t avoid going though shrubs, cactus, etc with your measuring tape

Line Intercepts

______: the number of individuals per unit of area

Good for measuring seedling emergence, survival, and mortality

Time consuming with high density species

Difficult with sod-forming species

Density

_______ is exact, for example 3 plants per meter squared

absolute density

methods for measuring density

Plot based

• small quadrats

• large quadrats

• belt transects

Plotless

• Point-centered quarter

• Nearest-neighbor

• Random pairs

• Wandering quarter

• T^2 method

procedures for _____ and _______: set out plot boundary, count individuals within plot, count density per area

large and small plots

belt transect

procedures for _________: Set out transect (plot length), Walk with pole held parallel (plot width), Count individuals falling within the “belt”, Calculate density per area

______: the organic material produced by the vegetation

Production

animals consume _____, not pounds

nutrients

_______: total weight of vegetation within a given area

biomass

______ and _______ can be used interchangeably

Yield & production

______-: total above-ground plant biomass on a site at a particular point in time

Fluctuates within and between years, depending on climate conditions and utilization by grazing animals

Standing crop

________: the maximum amount of above-ground biomass observed at a site during a particular year

Usually coincides with the end of the growing season

Peak Standing Crop

______: herbage or browse which is potential food for animals

forage

______: above-ground biomass of herbaceous plants (grasses and forbes)

herbage

______: the portion of woody plants’ vegetative material available for animal consumption

Usually the current year’s growth of twigs and leaves

browse

_______: fruits, nuts, and seeds (reproductive material) produced by woody plants and used as food by animals

mast

Why do we measure production?

Management indicator

Used to:

• Adjust livestock stocking rates

• Assess wildlife carrying capacity

• Assess site’s value for habitat

• Assess feasibility and potential behavior of prescribed fire

• Assess success of rangeland improvement practice

Wet weight

Dry matter corrected

Procedure:

• Lay out a quadrat or plot

• Clip all the aboveground biomass in the plot

• Place in paper bags

• Weigh the biomass

• Dry and reweigh

Direct measurement methods

• simple harvest methods

Double weight sampling

Capacitance meter

Rising plate meter

Comparative yield techniques

indirect measurement methods

Data is easy to interpret

Direct measurements require little training

Production is considered a good measure of plant dominance and site capacity

advantages of directly measuring data

Data collection can be very labor intensive and time consuming

Can have high variability of production between quadrats

• Cover, frequency, and density measurements are usually quicker.

Seasonal and annual climate fluctuations directly influence production.

• Density, frequency, and cover are less susceptible to variations in climate fluctuations.

disadvantages of directly measuring data

_____: how the vegetation is arranged in 3-dimensional space

Based on height of vegetation and / or visual obstruction

structure

Why do we measure structure?

To estimate value of habitat

• Thermal cover

• Hiding cover

• Nesting cover

• Movement patterns

To monitor ecosystem health

• Microclimate modification

• Degradation vs. restoration

  • Plant vigor

  • Use by grazing / browsing animals

to measure individual plant structure:

height and diameter

Nudds’ board

Robel pole

• Designed for primary use in grasslands.

• Originally designed for measuring nesting cover.

• Uses a pole that is marked in alternating black and white colors (150 cm tall x 3 cm in diameter).

• Black and white alternate every 10-cm

Hays’ vegetation profile board

vertical cover boards

Secure pole at sample location.

Observer stands 4 m away. This distance is usually marked with a string that is attached to the pole at a height of 1 m.

Observer lowers him/herself to sighting height and records the highest band that is completely obscured by vegetation.

Take observations from 4 cardinal directions around the pole at each sampling location and then average them.

Record all the bands which are ≥ 50% obscured by vegetation (live or dead) at 0- 60cm, and record all bands obscured ≥ 25% at 60-150cm.

procedure of vertical cover boards

Quick and easy to estimate vertical cover

Grass height highly correlated with biomass

• Good to use clipping and robel pole methods together for biomass estimation

pros of vertical cover boards

cons of vertical cover methods

Usually need two people for measurements

Gives an estimate rather than absolute value for vertical cover

to measure structure you use

Densiometers

Photometric (light) technique

vertical cover boards

_______: the proportion % of cover, density, production, etc. to the area’s total

Not measured in the field

Calculated later based on other measurements made in the field

Can be calculated from canopy cover, density, or biomass values

Can be calculated based on individual species or groups of species (grasses, forbs, shrubs, trees)

Also called: species composition or botanical composition

composition

why do we calculate composition?

Used to describe ecological sites and evaluate rangeland condition (ecological similarity index)

Measurements over time can be used to monitor changes in rangeland condition

Allows comparison of dominance of various species in the plant community

Usually more easily understood / visualized than other vegetation attributes

________: Expressed as a %

All vegetative components add up to 100%

Can be calculated using values from biomass, cover, or density

From biomass

• % composition of species A = (weight of species A / total weight of all species) x 100

calculating species composition

Stem Count Index (Browse Utilization Survey)

TPWD Procedure

Mast Production Measurements

Softball Habitat Evaluation Technique

Other Measurements Useful for Management Planning

______: Measures number of browsed stem tips out of a total sample

Stem Count Index (Browse Utilization Survey):

_______: At a location (plot), count browsed tips out of 100 stem tips

Minimum of 3 plants per species are sampled

No more than 34 stem tips counted on 1 plant

Calculate % browse utilization by species

Categorize species into 1st , 2nd, or 3rd choice palatability classes

Compare values to the stocking intensity table developed for the region.

TPWD Procedure:

_____: Weigh or count mast collected in traps

Estimating percentage of tree crown with mast

Counting mast density within plots

Mast Production Measurements:

______: Evaluates adequate access to loafing and escape cover.

Brush thickets should not be more than a softball throw (40 – 60 yds) from each other.

If you throw a softball 15 yards and still see the ball, the grass is too short.

If you throw it 15 yards and don’t see the ball, ground cover is thick enough for visual obstruction.

If you can drop a golf ball and roll it with your foot through the vegetation, the vegetation at ground level is appropriate for chicks

Softball Habitat Evaluation Technique: