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Looking for the invisible

Preamble: Gentle reader, it has been four months since I have appeared before you. Obligations and opportunities required my absence for a third of the year but now I am back. I am very pleased to be able to appear once again on the page in front of you. Reflecting upon my absence, I thought it appropriate to consider absence in our professional lives as well.

As biologists and students of natural history we are taught, and we try to train others, to be observant – to see and note conditions and features around you while in the field. Indeed, I would argue this is the primary activity of working professionals, hunters, fishermen, berry pickers… pretty well anyone interacting with or studying nature. Observation is the fundamental and primal task of anyone working outdoors. And some individuals are better at this than others; some disciplines or companies stress it while others do not. I have written before on this (Blog #1: Block Surveys), and will again due to its importance. But for this blog, in celebration of returning after four months absence, I want to consider looking for what is not there – identifying conditions by absence.

Almost invariably, when teaching or talking about observation we focus on seeing, identifying, and describing what is in front of us. But what is not there to be seen, but should be, can be more important than what we do view. The classic example is being near a wetland on a warm spring evening and noting the silence. Maybe you hear a light breeze whispering as it blows past your face. Perhaps also the creaking of leaning timber in a nearby stand or the sharp sound of the sedges grinding against each other in the light wind. But what about the frog calls? Where are they? Silence near a wetland at this time of year is unusual. The amphibians should be croaking and calling. Their absence is far more telling, and worthy of investigation, than the anticipated calls of pickerel, mink, or red legged frogs. Go and look in the water, do you see egg masses? tadpoles? It is the missing pieces that often alert us to something amiss, not what is there.

Identifying the absent ranges from the obvious to the invisible. A few examples include:

  • Silence or unusual quiet at dawn on spring mornings. Absent or muted birdsong during the nesting and rearing season is a thunderous indication of something amiss. Rachel Carson used this precise phenomenon as the title of her classic and influential book Silent Spring.
  • Lack of snags and wildlife trees in a forested area. It is not only that old and dead trees are valuable wildlife habitat, they are essential to forest health and nutrient cycling. Seeing none of these, or very low abundance, is always a worrying sign for me.
  • Absence of wildlife sign. Tracks, trails, scat, beds, cavities, nests, dens, feathers, game trails… in most healthy places I cannot take ten steps without seeing some form of sign or hearing calls of wildlife. When I can walk a distance without finding any evidence of use I know there is something wrong.
  • Fish-eating birds on lakes. A flat open lake surface without cormorants, grebes, mergansers, loons, or kingfishers is a lonely sight… and suggestive of a near-barren waterbody. These birds indicate the productivity of our lakes and streams.
  • Bats over water or around streetlights. In summer and in urban environments, around dusk I expect to see bats, particularly in these two locations. A few nights without observation of these night-flyers raises the question of where they are.

Having a vertebrate focus to my interests I have not even mentioned the plants but the same applies to that kingdom as well. We have well known indicator species that inform us of features of the environment, but the absence of those species, where they should be present, is also very telling. This can be particularly so with invasive species, which tend to dominate a viewscape. Not only should I be thinking about the presence of Himalayan blackberry or Scotch broom but also evaluating what species should be there but are absent.

But, of course, to acknowledge what is missing requires an understanding of what should be there. In looking at a stream I often see the lack of deep pools, absence of narrow channels, omission of woody material. Another observer looking at the same stream just sees what they think is a healthy waterway. They see what is present, not what should be present. For people new to the environmental practice – coming in with their strong academic and theoretical knowledge – we need to introduce them to what healthy, intact, natural systems look like. We need to ensure they see the parts required so that they will notice them when they are missing. Twenty five years ago my mentor did this for me; he made sure that we walked healthy vibrant streams before we looked at impacted ones. A man of the past yet before his time, he cultivated in me the understanding that most systems we now see and work in are fractured and disrupted, but they are so common that we think they are normal. We need to re-set our eyes and understanding by frequently visiting and studying healthy, functional, intact forests, grasslands, lakes, streams, and rivers. We need to calibrate our eyes. 

I urge environmental practitioners and all interested in the natural world to think about what we don’t see as well as what we do. This is the invisible ‘white space’ in art; it is the empty space around the paintings focal point that provides context. I further encourage people to get out into as natural and undisturbed settings as are available to them. To look carefully and deeply at the waterways, the meadows, grasslands, and forest stands. Train your eyes and mind for what intact functioning ecosystems look like – this is how we condition our brain to see the absent in those disturbed or altered conditions. 

Sean Mitchell