This is the fourth post in a series on riparian health. It gets down to the ‘nitty-gritty’ of working through the questions. If you haven’t already done so, please read the previous articles on the importance of riparian areas and the need for assessments.
Successfully navigating the riparian health assessment (RHA) procedure benefits from three key habits: tuning your eyes, taking good notes and being systematic. It also requires being conscience of your biases. And, you should also have some understanding of what is normal, or what might be missing or modified.
These tips relate to the procedures layed out in the Riparian Management Field Workbook. Start there by reviewing the eleven RHA questions and use these tips to help find the best answer.
Tuning Your Eyes: Estimating Cover
Several questions in the RHA require you to estimate cover. How much of the area is covered by vegetation? Of that, what percent are invasive species? How much in disturbance caused vegetation? What percent of the woody vegetation is preferred tree or shrub regeneration? How much bare soil is human caused?
Making visual estimates of cover can be tricky at first. But with practice and a systematic approach you will be accurate and consistent enough to get good results.
The first key is to familiarize yourself with the procedures of estimating canopy cover. Canopy cover is based on projecting the outer bounds of the canopy to create an imaginary polygon on the ground. Then, express that polygon a percent of the total area. A few things to note when you estimate cover:
- “Bare ground” includes any sediment deposited on top of vegetation via flooding;
- Don’t factor in large rocks or standing water in your determination of bare ground; and,
- Canopy cover can sum up to greater than 100 percent. This is counter-intuitive to some.
The main tip in assessing cover is to move around to ‘tune your eyes’ before deciding on a canopy boundary. This is particularly important for tall shrubs and trees observed from below. You won’t get an accurate impression of the canopy shape unless you look at it from several angles.
No Tree or Shrub Cover?
Several assessment questions relate to the cover and condition of woody vegetation at the site. Assessing a site with no tree or shrub cover can therefore, present challenges in the RHA.
Not all habitats support woody vegetation. If not naturally supported, their abscence is not an indication of poor condition. So, if you are unsure if they should be present, try find some supporting information. Try to locate nearby areas that have not been modified by human activity. Or, consult ecological guides that might describe the potential natural community.
Highly modified riparian zones might also have no trees or shrubs because of land clearing or repeated, heavy livestock use. In these situations, their abscence is an indication of poor condition.
If trees and shrubs do not naturally occur, you can skip the related questions (4/ 5 /6) and don’t factor their scores in the overall health scoring. That is, prorate the score to a total that does not include a contribution from these questions. If however, trees and shrubs are missing because of past management, then score these woody vegetation-related questions as zeros.
Keep Good Notes
Don’t feel trapped into making a final score for every question while you are at the site. Gather as much information as you can. Take photos, keep detailed notes, including estimates on the area of different conditions encountered. You can use these later to arrive at final scores with more time to reflect on the data in its totality. This may also lessen any bias introduced through what was last observed. And it will put into perspective segments of the riparian that create a strong negative impression.
Each question in the RHA has four possible choices. Extremes are easy to score. Areas either heavily modified or untouched are both easy to rate with the RHA. It is, however, sometimes more difficult to determine where a site falls between the middle two categories. That is, teasing out the differences between lightly to moderately impacted, or fair to good conditions.
Don’t get overly stressed about your selections. By design, there is some redundancy in the questions that are asked. And therefore, the answers to the proxy questions in totality, give a fairly robust and repeatable scoring of riparian health.
Practice Makes Perfect
Making visual estimates can seem overwhelming at first. And your first few assessments will take more time and reflection than when you are more experienced. But keep at it and hone your assessment skills. Practice will make you more comfortable with the process and your judgements. Working with a partner or a group can also help.
In the end, there is nothing magical per se about the total RHA score you determine. It is a guide towards the underlying health of the system you are observing. And it is a benchmark for measuring progress in your management goals.
When you work with the intentions, the riparian health assessment can be a valuable education tool. And education is big first step towards improving stewardship.