Photo: At the River’s Edges in Orgiva, Spain. Photo courtesy of Emma Gallagher.
I must begin with the confession that this article began when my wife asked me to better explain the edge effect, and I found myself stumbling through an explanation. We both knew the edge was something powerful and taking advantage of it a permaculture principle, but the clear reason—something akin to defining permaculture—seemed to escape us.
I delivered an explanation about how the joining of two ecosystems creates something different and remarkable, a melding of the two environments where plants and fauna congregated in abundance. I used the coastline as my example, and we stammered when speaking about the beach, which stymied me in its barrenness. Suffice it to say, I wasn’t satisfied with my explanation.
So, more clearly understanding the edge was entered on my to-do list, and I figured that, if I, in my verbose wisdom, had trouble pinning it down into something sensible, perhaps others might be struggling similarly. After all, we are meant to learn from our mistakes and share what we learn. That’s hard to do when we don’t feel fully abreast of something. Thus, without further ado: the edge.
Seeing the Natural Phenomenon
Like any good permaculture tenet, pursuing the edge effect is rooted soundly in astute observation of nature. I was right about that! And, not so far off in my explanation. Essentially, in those spaces where ecosystems and/or landscapes converge—water and land, or forest and prairie, or even quick changes in soil types—plants and animals are able to take advantage of both environments, and often a wholly different one created by the merge.
A classic example is the land and sea border of which I had spoken, but the focus is not the beach. Rather, when we look at the reefs right off the coast, we find the largest diversity and abundance of sea life, both swimming and stationary. On the other side of the tide, we find mangroves crawling with life and unique plants that can’t be found anywhere else. In each case, the two systems are interacting with one another, and the meeting of these two worlds brings not only the typical components of each but a whole new ecological system that takes advantage (and exists only because) of the fact that both set of ecological features are there.
Along edges, opportunities abound. For some plants and animals, it’s the opportunity to spread their wings or get some sun or cool off in the shade. They might find richer hunting grounds or more nutrient-dense soil or a steady source of hydration. At the edges, all sorts of material—leaves, wood, water, salt, scat, rocks, shells, fungus, bacteria—is exchanged, creating in its diversity the potential for a fuller, more abundant flow of energy.
Recognizing the Edge in Patterns
Of course, when we reduce the size of natural phenomenon from such grandiose examples, we can find the edge effect working in much more compact systems. Simple openings in forests or outcrops of rocks can create advantageous edges, and they are also apparent and naturally maximized in the way a stream meanders through a forest as opposed to moves in straight lines. More plants and animals can take advantage this way.
Our bodies use similar patterns. The human intestines winds and wiggles in our insides, extending the movement of nutrients through our systems, so that we can absorb more of the vitamins and minerals we need. The extended edge produced by both the winding of the system, as well as the tube’s wrinkly shape, means our bodies can take full advantage of what we put in it (assuming we are feeding it good stuff).
These sorts of extended edges exist all over the show: The spiral arrangements of seeds in a sunflower, the splintering of tree roots, the curvy line of lakefront. In each instance, no matter how small (the innards of a microbe) or how large (the Great Barrier Reef), this is how nature has adapted to take full advantage of the mystical edge effect.
Applying It to Permaculture Design
While I have considered edge in my designs, often avoiding straight lines, it seems I’d failed recognize fully the power of doing so. The obvious advantage that had always pleased me was that, like the windy windbag intestines, the curves and curls provided me with much more surface area than did blander geometric patterns like rectangles and circles. An undulating bed with keyhole entries obviously added a lot more edge and provided a lot more growing space.
Additionally, I’ve used vertical properties to create microclimates that replicate the edge effect. I’ve noticed that where my hugelkultur mounds meet the ground always has the most abundant and healthiest collection of plants because, of course, the water is collecting there, as are the nutrients it carries down the mound. Despite receiving the occasional shellacking over its practicality, I’ve also been a big advocate of the herb spiral, which creates both an extended edge via the spiral pattern, as well as a similar advantage (as the hugelkultur) with regards to elevation and energy/resource movement.
There are other opportunities to utilize edges. In construction, curves and/or zigzags make for much more stable, stronger walls and fences. With rainwater harvesting, a pocked ground surface captures and absorbs water where as a smooth plane hardly nets anything. Curved tree lines or hedges make for valuable heat-gathering and wind-blocking microclimates for more sensitive plants. Swales and paths on contour are another commonly seen extension of edge around which, no surprise, plants thrive.
It was funny, as a started to mind the edge more consciously, I noticed how much I am drawn to it. How, at the moment, I eat my lunch every day with my feet dangling off the porch of our riverside cabin. How, when it’s time to write, I always seek out somewhere to sit where I can enjoy the shade of the jungle but stare out at the waterway. How much, even though it’s not as quick, I prefer a winding path to a straight one. Perhaps it’s something primal within me. I can’t explain it, but I’m feeling a little more adept with permaculture’s take on the whole thing.
I would be remiss not to reference this article, posted on Deep Green Permaculture, for its assistance in understanding this issue and constructing this article While other sources undoubtedly were used in this pursuit, I’ve definitely pinched some examples and such directly from Deep Green. Fair share.