The Cover estimation 2-step, 3-step, 4-step...
Using cover estimation as a measure of abundance or the "amount of x" is often seen as the Achilles' heel of BCM, with groups of otherwise intelligent and experienced field officers often producing a shot-gun spray of estimates when posed the question "what is the cover of low shrubs in this quadrat", leading to doubts about the ability of the methodology to even detect change over time.
In teaching and doing BCM over the years, I have pondered this phenomenon, and agonised over the seeming impossibility of coming up with reasonable and repeatable estimates of projective cover. I think the problem comes from us trying to come up with an answer in one step.
Not wishing to over-complicate things, but I have become convinced in this matter that perhaps the road to confidence involves adding a few steps, which paradoxically, make the process simpler.
Basically, it involves working with "extent" and "density", and dividing the thing you want to measure into "manageable chunks", and then just a few back-of-the-envelope style calculations. Combined with cross-checking your results against other elements already measured, you can turn the ridiculous into the sublime (when you realise that the impossible is now a reality)
This is nothing new, I hear you say, but I rarely see it practiced in field work, and many otherwise experienced field ecologists often still treat cover estimation as the least defendable of their skills, even after many years of "practice". In the worst case, it can becomes dispiriting and demotivating.
BCM has developed a range of mental approaches to assist with measuring projective cover, which, when done carefully and realistically, is still the best value for money and time spent in estimating abundance of vegetation components against the background of seasonal and yearly climatic variation.
