With every change we make in the environment, many ecological changes follow. We have learned, that keeping track of these changes is very important, but unfortunately, we still don’t do it as much as we should. Monitoring is very important because it gives us an overview of what’s happening in the environment. In this way, we can take action right away if we see decreasing ecosystem health. Usually, monitoring is done after anthropogenic interruption (building a hydro-power plant, renaturation process) or (less often) after a natural hazard (volcanic eruption, wildfires etc.).
For tracking the changes we use chemistry as well as live, free-living organisms. Chemical analyses show us what’s happening in the environment at the specific moment when the sample is taken, but don’t show us the past. Live organisms, however, show us what was happening in the environment on a larger time scale (the ones, that couldn’t survive died or migrated and are therefore absent or at least represented in lower numbers than usual for this kind of habitat). The kind of monitoring, that uses live organisms is called biomonitoring and the organisms, that indicate the changes are called bioindicators. There are different ways of monitoring. One is listing the present organisms and the second is capturing them (sampling), which can be done actively or passively. When sampling, we need to make sure that we make the whole procedure in the same way (same equipment, intensity etc.) to ensure that the results are comparable. The captured organisms are later identified or analyzed, with appropriate equipment in the laboratories.
What are bioindicator organisms?
These organisms can be organisms that do (keystone species or ecosystem engineers) or don’t seem to have a special role in the ecosystem. What these organisms have in common is, that they are sensitive or tolerant to some things, present in the environment surrounding them. These ”things” can be specific elements (nitrogen, phosphorous), abiotic factors (temperature, oxygen levels, pressure), pollution (heavy metals, fertilizers) etc. To be able to conclude what the presence of a specific organism is showing us, we need to know as much as possible about them (biology, behavior, morphology, the ratio of elements in tissues etc.) when they live in (for them) good/normal conditions.
What is their language?
We have actually found a way to make them talk and they do so in many different ways. Some organisms are bioindicators by just being present, and for others, we use some methods (analyses) to make them speak. We can analyze their tissues (bones after death, tissue) just by looking at them or by chemical analysis. Organisms can also indicate the ecosystem health through their morphology, metabolism, behavior or structure and number of their populations.
When talking about polluted areas, we are actually talking about places, where levels of one or more elements are higher than tolerated. With the term ”tolerated value” we have set a level, that doesn’t have any influence on human lives (but can influence lives of other organisms).
We monitor water, soil and air quality
In each of the given environments, we come across different species and we also use different sampling methods. We need to keep in mind, that diversity variates due to geographical location as well as environmental factors (seasons, vegetation density and species, pressure, temperature, etc.).
Interactions between organisms
Bad health of a water body can be told from far away if we see algae. Usually, they grow in high densities in standing water (lakes or other accumulations) but can also be present at the coast. Their presence indicates high levels of nitrogen and phosphorous (the latter is usually less common and therefore limiting element). High levels of these two elements are usually showing organic pollution (sewage inputs, the presence of fertilizers, waste from factories) and usually result in algal blooms. These blooms can be (in some cases) life-threatening since some algae are able to produce toxins. When the food supply runs out, the algae begin to decompose. In this process, decompositors are using a lot of oxygen in order to break the organic matter into basic elements, leaving little or no for other organisms.
Another way to say how healthy a water body is is by catching, observing and, identifying the organisms living in it. We usually look at communities of benthic macroinvertebrates (small creatures, mostly living in spaces between the rocks). Each family, genus, and species within this group indicates specific living conditions and by looking at the whole community, we are able to get a bigger picture and assess the health status. Another way to assess the health status of the ecosystem is to observe the development of an embryo (this is usually done for bigger organisms such as frogs and toads) or to check the heavy metal levels in fish liver (they accumulate there).
We can use many indicators for assessing the health of the soil. For monitoring the presence of heavy metals, the best method is to use mushrooms, due to their high capability of storing them. The health of soil can also be (and usually is) measured with the diversity of organisms living in it, as well as with their specific role in an ecosystem (herbivore, predator, decompositor, etc.).
Air quality is most often assessed by listing species of lichens and mosses. Lichens are actually two organisms (fungi and algae) living in a symbiosis. Both mentioned bioindicators can be found on tree trunks, rocks, etc. but some species are only found when certain criteria are met. This last characteristic makes them very frequently used in research of air quality, climate changes and determination of pollutant levels. Besides the fact that both of them are able to store many bad things from the environment, they also can’t run which makes them easy to deal with.
Biomonitoring enables us to track the changes and foresee the upcoming problems, but it needs to be done frequently. One of the reasons for this is the seasonal changes and the other is our luck. By this, I would like to point out, that sometimes the organism is present, but slips between our fingers. This gives us an impression that it is not present, but it actually is. However, there is still a lot of research to be made in order for us to get a better picture of processes in nature. However, maybe in time, we will be able to better predict what a certain change brings and won’t need to first do something and then regret it.
Did you know that this kind of monitoring exists before you have read this article? What do you think about it? Should we do more or do we do enough for our planet? Please leave me a comment and tell me what you think.