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WHAT IS ENDEMISM AND WHY SHOULD YOU CARE?

Updated: Mar 26

By Annie Nguyen

In my research to understand the structure and drivers of flora that are on volcanic soil in eastern Australia, I often use the word endemism.
Que the question: what is endemism?
The endangered Red Cross Spider Orchid (Caladenia cruciformis) is found only within the J.C. Griffin Nature Reserve, Victoria (Photo: Matthew Newton, 2020).

The textbook definition is somewhere along the lines of:

A taxon (e.g. a species) is considered endemic to a particular area if it occurs only in that area.” (Crisp et al., 2001)

Can you see the problem here? Let me give you the most obvious example to this problem.

Humans are endemic to Earth.


Does this give you any sense of justice to the vast differences in culture that is expressed in exquisite cuisines, languages, and even stark appearances between ethnicities?

Furthermore, to say that you are endemic to an address also leads to a misleading conclusion as it is only true of your current situation.


As you can see, the definition is so vague that it changes with time and space; i.e., scale relative to a given time frame.

Scientists like to be mathematical about it and approach the problem by devising complex equations that divide areas into cells or grids that may or may not take into account a range of weighted factors such as topography and climatic boundaries. The result is a map of species (which may be at any taxonomic level, but tends to be at the Family, Genus or Species level) that appear to be restricted in range to a certain area, usually within the present (time).


As an example, at least 209 amphibian, 252 mammal, and 358 bird species are endemic to Australia in 2019 (Our Word in Data, 2020; see below).


In 2019, at least a) 209 amphibians, b) 252 mammals, and c) 358 bird species are endemic to Australia (Our World in Data, 2020).

Australia is doing pretty well on the endemic scale in global comparison but at the end of the day, why does it matter? Why are scientists pulling their hair out over how restricted a species’ range is, and more importantly – why should you care?

You may know that the first antibiotics were derived from fungi, but did you know that more than half of all commercial medicines contain compounds initially deriving from wild species (Mittermeier et al., 2011)? These wild species may be rare (limited in number), endangered (at risk of extinction) and endemic (limited in geographic range).


In addition to medicine, many of our greatest engineering feats are inspired by species in nature. From the bullet train inspired by the kingfisher’s bill (Crandell, Howe and Falkingham, 2019) to NASA’s aircrafts inspired by the albatross (Bowers et al., 2016). Evolution has done all the hard work for us and we merely need to look to nature for rules of efficiency.


So you see, if we fail to conserve species that are endemic to a certain locality, say a mountain top, that requires specific conditions to exist, we may inevitable be short-changing humanity into a situation whereby the opportunity to realise a species resourcefulness may never be discovered. Not to mention the numerous benefits of simply living near a naturally protected area (see Naidoo et al. 2019).

Further to the argument, the functions of many endemic species may be crucial to the survival of other species. For example, some Eucalypt species endemic to Tasmania has evolved traits that enable anti-herbivory predation (Gorman et al., 2014). This indirectly impacts other species where the herbivores have been redirected to obtain food. It is even more alarmingly important to protect endemic species if they also function as a keystone species, i.e., a species that is disproportionately important relative to population size as they usually uphold the structure of an ecosystem. For instance the Southern Cassowary (Casuarius casuarius johnsonii) is a keystone species that is endemic to protected pockets of rainforest in northern Queensland (Campbell et al., 2012). The Southern Cassowary consumes and disperses the fruits and seeds of many rainforest species far and wide, without whom they would struggle to survive (Bradford and Westcott, 2010). As a chain reaction, without those species that rely on the Southern Cassowary, other species that rely on those would also become vulnerable and so forth.



Distribution map of the Southern Cassowary (Latch, 2007).

Globally, approximately 1.5 million species are formally described. However, the total number of species that may exist varies anywhere between 2 million to 11 million (Larsen et al., 2017). One of the key reasons for this wide bracket is because many species have very niche habitats that make them endemic to a very small area. As a result, species with potential properties, medicinal or otherwise, may never be discovered if we choose to continue unsustainable development that threatens endemic species and biodiverse areas in the short term, but humanity’s own demise in the long term.


All posts are personal reflections of the blog-post author and do not necessarily reflect the views of all other DEEP members


References


Bowers, A. H. et al. (2016) ‘On Wings of the Minimum Induced Drag: Spanload Implications for Aircraft and Birds’, Nasa/Tp—2016–219072, (March), pp. 1–22.


Bradford, M. G. and Westcott, D. A. (2010) ‘Consequences of southern cassowary (Casuarius casuarius, L.) gut passage and deposition pattern on the germination of rainforest seeds’, Austral Ecology, 35(3), pp. 325–333. doi: 10.1111/j.1442-9993.2009.02041.x.


Campbell, H. A. et al. (2012) ‘Prioritising the protection of habitat utilised by southern cassowaries Casuarius casuarius johnsonii’, Endangered Species Research, 17(1), pp. 53–61. doi: 10.3354/esr00397.


Crandell, K. E., Howe, R. O. and Falkingham, P. L. (2019) ‘Repeated evolution of drag reduction at the air–water interface in diving kingfishers’, Journal of the Royal Society Interface, 16(154). doi: 10.1098/rsif.2019.0125.


Crisp et al. (2001) ‘Endemism in the Australian flora’, Journal of Biogeography, 28(2), pp. 183–198. doi: 10.1046/j.1365-2699.2001.00524.x.


Gorman, C. E. et al. (2014) ‘Shifts in species interactions due to the evolution of functional differences between endemics and non-endemics: An endemic syndrome hypothesis’, PLoS ONE, 9(10), pp. 1–6. doi: 10.1371/journal.pone.0111190.


Larsen, B. B. et al. (2017) ‘Inordinate fondness multiplied and redistributed: The number of species on earth and the new pie of life’, Quarterly Review of Biology, 92(3), pp. 229–265. doi: 10.1086/693564.


Latch, P. (2007) Recovery plan for the southern cassowary Casuarius casuarius johnsonii, Report to Department of the Environment, Water, Heritage and the Arts, Canberra. Queensland Government Envronmental Protection Agency.


Mittermeier, R. A. et al. (2011) ‘Global Biodiversity Conservation: The Critical Role of Hotspots’, in Zachos, F. E. and Habel, J. C. (eds) Biodiversity Hotspots. Springer. doi: 10.1007/978-3-642-20992-5.


Naidoo, R. et al. (2019) ‘Evaluating the impacts of protected areas on human well-being across the developing world’, Science Advances, 5(4), pp. 1–8. doi: 10.1126/sciadv.aav3006.


Newton, M., (2020) ‘Rare Victorian Orchids’, Bush Heritage Australia, Available Online at: https://www.bushheritage.org.au/species/orchids (Accessed 03/11/2020).


Our World in Data. (2020) ‘Endemic amphibian species by country, 2019’ Available Online at: https://ourworldindata.org/grapher/endemic-amphibian-species-by-country (Accessed: 30/10/2020).


Our World in Data. (2020) ‘Endemic bird species by country, 2019’ Available Online at: https://ourworldindata.org/grapher/endemic-bird-species-by-country (Accessed: 30/10/2020).


Our World in Data. (2020) ‘Number of endemic mammal species, 2019’ Available Online at: https://ourworldindata.org/grapher/endemic-mammal-species-by-country (Accessed: 30/10/2020).


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