Biodiversity. A term used and abused by now in all climate conversations. A term that takes me back to that university lecture 12 years ago, when the professor with the Scottish accent (also going by the name of John Spicer) taught us some very important first lectures (and I really wish my English then was at my current level, but thankfully he also wrote a great book ‘ Biodiversity: A beginner's guide’ - which i recommend to anyone interested in the topic!) Biodiversity is important. We get that. Yes, really… but why? Ever asked yourself that question? Or are we just repeating it as a ‘dogma’? If we start to answer the why then we may able to answer the ‘which’ (yes, because there is not just one “biodiversity”) and start to plan and mitigate its losses. So. Let’s take a step back and try to see first WHAT it is by being clear about what is NOT.
Biodiversity is NOT simply the equivalent of having a lot of species. That can be simply defined as species richness - and it’s not always useful. To understand biodiversity we may want to introduce the concept of evenness. Imagine two scenarios: (1) four cows, four sheep and four chickens (2)nine cows, two sheep and one chickens They have both the same number of animals, the same number of species but the second is higher in cows. The number of individuals are not evenly distributed across the three species. The species higher in number of individuals may have a disproportionate impact on the environment. It may eat more of a certain resource, in the case of cows it may be trampling more, being heavier than the other two. And the single chicken is likely unable to reproduce. leading to either migration or extinction. And this was just a simple example..... And then, one may think about the spatial scale at which biodiversity is measured. Meters? Kilometers? Thousand of kilometres? Biodiversity is complex. As complex as one of its definition ‘the biological variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic, species, and ecosystem level’. So, we are not even just talking about many species, but even genetic diversity within a species is essential and important. yes, okay, but WHY is important? Biodiversity has some clear linkages to ecosystem services. This seems pretty straight forward: more species should lead to greater functionality as each species is characterised by a certain behaviour, more species should be equal to more behaviours. Let’s make two scenarios again three species: (1) Cow, Sheep, Goat (2) Cow, worm, bee Cows, sheep and goats are all grazers, and while they graze in different ways (goats for example are known for completely uprooting plants while the others don’t), it surely makes less of a impact on the functionality of a system where we have cows, worms and bees. The worms will help keep the soil healthy for the plants to grow and the bees will help pollination and so on… So FUNCTIONAL biodiversity seem to be important for functionality of the system. Genetic diversity within species on the other hand can be very important for species to be able to cope with various levels of environmental change or disturbances. Some individuals may have some genes that make them more able than other individuals to survive and the species will keep through. I am sure many of you have learnt something about it in school, perhaps with the example of the white and black moth story during the industrial revolution. Are you going to remove the dust from that biology book from high school to check? To conclude, a rich and diverse habitat is more functional, and I should mention that 'functional' is also very convenient for "us" (humans, also nature by the way), because we rely on the functionality to survive! And actually, a more diverse world will also be more able to rebound back from disturbances (that are more and more common), so…. we need biodiversity. But knowing why we need it is probably better than just repeating as a 'fact'...
1 Comment
Jane
11/28/2021 06:59:19 am
This is excellent. Can you share to wahv fb group?
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