Keep an eye out for these five things to see if your rangeland is living up to its potential
The most important tools you have to assess the health of your rangeland are your own two eyes.
“What a range health assessment does is provides a measure of how well rangelands are performing key functions,” said Ross Adams, range management specialist with Alberta Environment and Parks. “It would be difficult and expensive to go out and measure those functions directly, so the assessments are based on more easily observed indicators that can be rapidly evaluated.”
Healthy rangelands (whether native grasslands or tame pastures) may look different based on where they’re located, but they share something in common — long-term stability in all of their key functions, whether that’s producing forage, protecting the soil, capturing water, storing carbon, or supporting biodiversity.
So an assessment is really comparing the current state of the site to its potential, Adams said during a Cows and Fish webinar last month.
That potential depends on climate, soil, and landscape, but a provincial range health assessment guide outlines baseline parameters for different regions and sub-regions across the province. Once you know where the gaps are in your operation, you can evaluate whether your management practices are working effectively, said Adams.
“It provides a quicker and easier method than going out and trying to measure functions directly,” he said.
And that starts with training the eye so you can quickly see “the different components of rangelands and what their potential is.”
Site selection and plant communities
Start by choosing a representative site (or several if sites differ considerably).
“Some site types may show radically different vegetation or response to disturbance than others, so it’s helpful to evaluate them separately,” said Adams.
While it can be a fairly involved process to differentiate between site types, each will have a ‘reference plant community,’ or the plant community that can be found under light disturbance.
Rangeland plants typically fall into the categories of ‘decreasers,’ which are highly productive but decrease with disturbance, and ‘increasers,’ which are more tolerant of disturbance but less productive. Increaser plant species begin to invade the rangeland when decreasers become less dominant on the landscape.
“Under light grazing, the plant community is basically at its reference condition, and the score decreases as you see that shift from decreaser-dominated to increaser- and invader-dominated plant communities,” said Adams.
“Those are sites where communities have become so disturbed that they become invaded by non-native vegetation, and in many cases, those plant communities may not be able to revert back to reference conditions under realistic management.”
So the first step is simply taking a walk and making note of the most abundant plant species.
“If the plant community closely resembles the reference plant community, the site will receive a high score,” he said. “But as that site becomes more disturbed and decreaser species are beginning to be replaced by increasers and invaders, the score will be reduced.”
Layers, litter, and soil loss
Next, look at the physical structure of the plant community — “the layers the plants fit into and whether all of the expected layers are present on the site.”
Those layers are above and below ground, ideally including both shallow- and deep-rooted plants, as well as above-ground vegetation of different heights. Diversity above ground allows more efficient capture of energy and nutrients while different depths of root systems mean “they’re not all competing for the same nutrients.”
This measurement of range health is scored much like the first — take a walk and take a look. But instead of looking at individual species, look for different layers: Short grasses, tall grasses, forbs and shrubs, moss and lichen, even trees.
“The changes can be fairly subtle in grasslands — there’s not as many functional layers — but tall grasses tend to be the first to drop out under disturbance, and then we see a shift toward lower-statured plant communities with very little structure,” said Adams.
Next take stock of how much litter is on the soil surface.
To determine if you have enough litter, rake up all the dead plant material on the soil surface of a 50×50-centimetre plot. Then use the guide (available at www.alberta.ca/range-health.aspx) to see if your site has enough litter based on your region. More litter is usually better.
“It helps to shade and cool the soil surface, which helps to retain soil moisture and enhance forage production during dry periods,” he said. “It also protects soil from raindrop impacts, enhances infiltration, and reduces run-off, so erosion is less likely to happen where there’s adequate litter. It also contributes organic matter directly into the soil.”
Next, look for evidence of human-caused erosion or bare soil — emphasis on human caused.
“Especially in grasslands, there can be sites that are naturally unstable or have naturally occurring bare soil simply because they are in a topographic position or have some chemical characteristic that limits plant growth.
“In that case, instability or bare soil is not an indicator of human-caused disturbance, but rather just a natural characteristic of the site.”
Things such as soil loss, compaction, bare soil, and erosion are indicators that the site isn’t healthy or stable, so you’ll want to make note of these problems.
“The more widespread and severe the issue, the lower the score will be.”
Training the eye
Finally, look for noxious weeds.
“Weeds are an indicator that the plant community on the site has become stressed and is less able to compete with incoming invasive plants, which can be time consuming and costly to manage,” said Adams.
“It’s much easier to manage weeds if they’re in a couple of localized patches rather than spread out throughout the pasture. As weeds become higher in coverage or more widespread throughout the pasture, that will lead to a reduced score.”
Having done the assessment, think about what, if anything, you need to change in your management.
“Looking at those individual indicators can help to diagnose the specific management issue that’s causing the decline and will suggest how to address it,” he said.
“It’s worth looking at where in the indicators (that) the numbers are coming down. Is it an issue where the plant community is looking good but there are noxious weeds? Is there too little litter? Or are there broader-scale issues that are causing the plant community to shift?”
On most operations, conducting a formal health assessment — complete with guidebook and checklists — won’t be necessary every time you want a snapshot of your rangeland health. But when you’re starting out, these tools can help you train the eye.
“As time goes on and you have more experience, you can almost start doing these in your head. You’ll just know where to look and what you’re keeping track of.”