To say that biodiversity is a complex field of study is a major understatement. Scientists and conservationists have spent many years studying the intricate details of biodiversity and the real-life application thereof. Everyday we continue to learn even more about this extraordinary field of study. There are however a few basic concepts relating to biodiversity which form the foundations of this field of study. It is from these concepts that the entire subject of biodiversity sprouts from, making it critical to understand the biodiversity basics.
In this blog post we will look at these biodiversity basics, stripped down to its core. The first aspect to look at is the definition of biodiversity, and its two different components. This will be followed by the different levels of biodiversity and the importance of each of these levels in real life. Unfortunately, there are significant threats to biodiversity, and in order to protect the biodiversity we must understand these threats. We will lastly have a look at these as well.
Defining biodiversity
Ask different sources to define biodiversity and you are bound to get differently worded answers as to what biodiversity is. A term so loaded with information is guaranteed to be defined in a multitude of different ways. However, regardless of how your definition of biodiversity is worded, the concept comes down to two distinct parts found within the word. These parts are ‘bio’ and ‘diversity’.
Diversity is the simplest of these two parts and comes down to the variety or differences found within this concept. It is this part which provides the scale of measurement for biodiversity, as conservationists can measure the levels of diversity and conclude whether it is healthy and if it is showing signs of increasing or decreasing.
We now get to the complex part of the term namely ‘bio’. In Greek, the word ‘bios’ means life and ‘bio’ from biodiversity is derived from it. Biodiversity thus means the variety of life on earth. But what is included within this concept of life? A common misconception is that the ‘life’ in this term only refers to animal life. This could not be further from the truth. Biodiversity relates to the variety of all life on earth. Included herein are all 5 kingdoms of living organisms. These are Animalia and Plantae (Animals and Plants) but also includes the kingdoms of Fungi, Monera (Bacteria) and Protista (Algae and Amoebas).
Included in biodiversity is thus everything from small single celled organisms to megafauna such as elephants or whales and everything in between. So, what aspects do this diversity or variety refer to might be your next question. Is it different species within an area or different individuals within a species? Or maybe even different ecological systems in a country? The quick answer to this is all of the above. This is where we find the three different levels of biodiversity namely genetic diversity, species diversity and ecosystem diversity. Let us dig deeper into these three biodiversity levels.
The three levels of biodiversity
The different levels of biodiversity hold the key to understanding the importance of biodiversity. Understanding the characteristics and importance of these levels helps us to better grasp the intricate and interconnected web of life. Each of the levels of biodiversity flows into the next, with the first being genetic diversity.
Genetic diversity
Within a population of a species, different individuals exist. The individual is the lowest form of organization within an ecosystem. These individuals all have specific traits and characteristics which are derived from their unique genetic makeup. The collection of all these different genes of a population is known as the gene pool. The gene pool of a specific geographic population is directly linked to its level of genetic diversity. A higher number of different genes in the gene pool means the population has a higher genetic diversity. The importance of this cannot be underestimated. One of the biggest functions of biodiversity in natural systems is to build resilience to changing conditions. The higher the genetic diversity of a population is, the more resilient the population thus is and the better it will be able to adapt to change.
Let us look at an example specifically related to genetic diversity. In our current world, climate change is a pressing reality with average global temperatures continuing to rise. If we have a small population of isolated Zebras for example, their genetic variation will possibly also be small. Let’s say that they are not well adapted for warmer temperatures and have a low heat tolerance. As temperatures rise, this population will start to become locally extinct as they cannot adapt to rising temperatures.
If we now look at the same group of Zebras in the same geographical area but with an increase in numbers and an influx of individuals from outside, some very important changes happen. The gene pool of this population will probably grow bigger and more diverse. There is a good chance that some of the individuals will have a high tolerance for heat. As temperatures rise, these individuals can thus still reproduce. This will lead to the survival of the population as well as the offspring having the characteristics of higher heat tolerance to a certain degree, thus resulting in the population having adapted to the changing environment (higher resilience).
Species diversity
We now move to the next level of biodiversity namely species diversity. Populations of different species within a geographical area make up different communities. A herbivore community within the Kruger National Park can consist of different species such as Eland, Kudu, Wildebeest, Klipspringer and Duiker. This level of diversity shares many of the same traits with genetic diversity such as building resilience and increasing adaptation. Species diversity however focuses more on the general stability of the community and the area in which they live, as well as the stability of the different functions and processes within this area.
Our example for this level of diversity relates to the Kruger herbivores mentioned above. When looking at seed dispersal of plants, a common method of dispersal is for seeds to stick to the fur of herbivores and disperse as they walk about. Carrot-seed grass and spear grass are prime examples of this. If we now have a community with only Duikers and Kudu in, the diversity is relatively low. Let’s now say that an illness wipes out the Kudu population, the sedentary nature of the Duiker will effectively mean that the seed dispersal through fur does not take place. This function thus becomes lost.
If we now have our community consisting of various herbivores, and the Kudu gets wiped out, other species can still take over this function of seed dispersal such as the Eland or Nyala. Higher species diversity thus builds higher resilience. Although this example is quite simplified, the principles all stay the same as natural systems become more complex.
Ecosystem diversity
The third and final level of biodiversity is ecosystem diversity. This type of diversity encompasses both biotic and abiotic (living and non-living) factors and relates to the number of different habitats and communities with a specific area. This type of diversity is directly linked to various ecological processes and systems including nutrient cycling, the water cycle, carbon storage and the regulation of climatic systems.
As with the other two levels, higher diversity leads to higher resilience. An increase in biological communities ensures that there is a type of ‘insurance policy’ for the critical ecological processes to take place should one of the habitats or communities suffer large scale damage.
The value of biodiversity for people
A huge advantage that people get from healthy ecosystems is that of ecosystem services. This term at its core relates to the advantages which humans derive from nature, specifically when our natural systems are healthy. The list of these advantages is extensive and incorporates all the products and services which we get from nature, from food sources to nutrient cycling and even medicinal resources and recreation.
Every aspect of our lives is in some way or another influenced and supplemented by nature and our human wellbeing is thus directly linked to biodiversity health and the subsequent ecosystem services. This can range from indirect links through processes such as pollination or nutrient cycling to direct links such as the livelihoods of people in the nature tourism industry. If the inherent value of nature is not enough motivation for us to protect our natural biodiversity, then surely the health of our ecosystem services should be.
Threats to biodiversity
When nature degrades and is damaged, it is inevitable that biodiversity will suffer across some or all of the three different levels. This is evident in the unfortunate decline in biodiversity worldwide. Globally, there are five major categories of threats towards biodiversity. One of the most pressing is that of habitat loss. When we think about it logically, if habitats are lost, the living organisms within the habitat will also be lost and thus the genetic and species diversity in the area will decline or disappear.
The second major threat is that of climate change. As the environment changes, some systems might not have enough resilience to resist the change and will not be able to survive. Overexploitation is the third threat and relates to the loss of biodiversity due to overutilization. If resources are used quicker than they can replenish, the numbers will decline and biodiversity will thus be lost.
The second last threat is that of invasive species. Due to the absence of natural competition of invasive species in a specific area, these species often experience a population boom as it outcompetes native established species. The loss of the native species and diversity of species lead to a monopoly for the invasive species and a subsequent decline in biodiversity. The last threat is that of pollution of all different sorts. Increased pollution equals degrading habitats. This causes a decrease in populations and communities as the environment is not suitable for the living organisms. When these groups decrease, biodiversity will decrease as well.
So how do we combat these threats you may wonder? In my opinion, through two main factors namely education and collaboration. I believe that through teaching the basics of these concepts, each individual can identify areas where they can help and improve biodiversity. The problem is however way too big for one individual or organization to solve it and requires worldwide collaboration and participation. Thus, once education takes place, collaboration should follow and everyone should do their bit to form part of the global collective.
Luckily, this is increasingly happening more as the value of biodiversity is realised and everyone from individuals to governments are starting to implement systems and processes to combat these threats. It is unfortunate that biodiversity has declined, however there is hope through all that is being done to reverse this. Some examples include the establishment of Marine Protected Areas or the declaration of international awareness days such as World Wetlands Day to name a few. I hope that you will be inspired to continue learning and contributing to the global effort to conserve and protect biodiversity.
Be filled with nature
Willem🐛