Why I like endemic species
I am writing this post having climbed up Mt Abrupt, Mt Sturgeon, The Piccaninny and Signal Point in the Southern Grampians/Gariwerd. It's a stunning place. Hiking in spring to early summer is really the best time. You see the iconic Xanthorrhoea australis in flower, the understory is rich in colour from the many peas, Grevilleas, Banksias and orchids. Whilst the biodiversity is great, the real surprise for me was the number of endemic species. To give some stats, the national park contains approximately a third of Victoria's vascular plants. 54 of which are endemic species, that is, they are only found in this National Park.
Endemic just means limited to a single defined geographic area (e.g. an island, a mountain range, a region or state etc).
It can be hard to explain why I find endemic species so cool. When talking to others, I get these reasons jumbled up, and it possibly reduces clarity. The coolness of endemic species isn't due to one reason alone, there's multiple. So I will try to distill it down to a list of reasons (and in no particular order).
These are not the only reasons, but are the ones I personally find most compelling.
1. Nowhere else in the world
On one of my hikes I was climbing up Mt Abrupt. Having done my homework beforehand, researching the various species, I knew there was a good chance of finding the Mt Abrupt Stringybark or Eucalyptus verrucata. That is right - this mountain (which is only 805m, very small really) has its own Eucalypt species.
I searched along exposed peaks and ridges, where it can be found. Sure enough I found both the Mt Abrupt Stringybark and the Grampians Stringybark Eucalyptus serraensis. Both are closely related and quite similar morphologically, however the Mt Abrupt Stringybark has larger buds and fruits with typically more valves (up to 6). Both species are endemic to the Grampians.
Eucalyptus verrucata the Mt Abrupt Stringybark, its habit (above), flowers and fruits (below):
This hopefully provides an indication of just how many endemic species exist here, the high endemism of the Grampians. The sheer fact that these endemic species exist at all is cool. I am amazed by their existence, but why?
Maybe its due to humans inherently giving value to rarity. But rarity isn't the exact word I am after. This rarity is all relative anyway. Yes endemic species can be rare, but equally endemic species can also be locally very abundant. It changes with spatial scale. The plants that are endemic to the Grampians are also endemic to the state of Victoria. One is a subset of the other. Does the smaller the area in which a species is endemic matter? Does it make those species even cooler? Every species is endemic to somewhere, but it does become more redundant and less meaningful as you reach a global scale. When this spatial scale becomes too large we tend to start using the term 'native' (e.g. 'Native to Australia' or 'Native to X country/continent'), and there is an understanding that it can likely survive in a range of different environmental conditions and ecosystems. Hence there is a connotation that comes with endemic, that it is specific, and only found in a certain area, and under certain conditions.
But that still doesn't answer why I am amazed by the existence of an endemic species.
Framing it like this makes it seem like there should be a reason, or as if it's existence needs to be justified. It doesn't. Yet I still find it remarkable, the knowledge that once leaving this place, you will likely never come across this species again. There is also no guarantee that you will be able to observe this species again, even if you do return later.
To see an endemic species, it sort of like you had to be in a specific place, at a particular moment in time, to even get the chance to observe this species (especially for animals). It is a moment. For me its almost an existential moment (though not always), where you can acknowledge and appreciate another species surviving on this planet called Earth. To return to where I started, maybe its not the rarity of the plant that I find cool, maybe its the rarity in the experience of finding an endemic species. I am aware I am now getting a little hippy-dippy, but nevertheless its a genuine reason.
2. Gives interesting environmental and evolutionary insights
Endemic species force you to think big. Big picture stuff. To seek any sort of explanation, you are forced to start considering the local environment, how this was formed and the evolution of the species in question.
In our case, the geology of the Grampians helped set up a unique environment that allowed endemic species to proliferate. Around 400 million years ago the Grampians were a seabed that was uplifted to form what's known as a Scarp Cuesta. This has since eroded (in the order of thousands of meters) overtime. All of a sudden your mind imagines how all the landforms and terrain has changed over millions of years, and the various conditions this might bring. Not to mention the changes in climate that have also occurred concurrently.
All these conditions (or rather niches) is also something you can observe. As you walk from the lowland areas to the high peaks in the Grampians, there was a clear and distinct zonation of species. Especially amongst the overstory species. Suddenly moving only 10 meters higher in elevation, all the Callitris woodland changed to Eucalyptus serraensis. It's this zonation that makes you realise all the environmental niches, and shows how the combination of environmental factors can work together, ultimately selecting for the extant species we observe today.
In the context of plants, I am sure the aspect, slope, rock types all influence where and how soil forms, root space and nutrients available, whilst causing some areas to be inundated during rainfall events, and leaving other areas with significant runoff and no water infiltration.
Further, you can also hypothesise as to whether these endemic species always had a restricted distribution, or was its distribution once much larger but has since contracted? If the latter then these remaining areas where it can be found can be thought of as refugia, that are home to relicts of the past. For an example of this, I like to think of the Wollemi pine in the Blue Mountains. Or even Lilly Pillies in the warm temperate rainforests of Wilsons Prom.
However this is not the full story! There are even intrinsic factors, usually specific to the biology of a certain species, that can cause a species to be endemic to a particular place. And these have nothing to do with the geology, or the surrounding environment.
On the walk up Mt Sturgeon I discovered Stylidium soboliferum Grampians Trigger Plant in flower - another endemic to the Grampians.
I am also fairly certain it has an association with an ant species too! As the many times I saw this plant it was always in close proximity to an ants nest. It's blurred in the photo above, however it could be possible, that this species relies on ants for its seed dispersal. Conversely, I may also be talking complete rubbish. In fact its more likely than not.
But to continue on... this may be a case of Myrmecochory, known to be common in other species, such as wattles (wattle seeds even have a protein reward, called an elaisosome for the ants). Thus the plant may be limited by the how far these ants travel. The plants can only expand their range to where the ants can carry the seeds.
Of course these plants and animals don't just exist in isolation. They have co-evolved to live with one another. I got a nice photo of a Banded Bee Fly (Tribe Villini) on a Eucalptus serraensis:
Plant-pollinator interactions can be highly specialised. Without a fertilised flower no seed will develop. Pollination failure can occur for a variety of reasons, (e.g. due to no nearby male/female flowers, or requiring specialised pollinators to fertilise these flowers (e.g. buzz pollination in Dianellas). The range of the pollinator effectively limits the range in which these plants can expand to. Also, some plants require a specific herbivore to eat the fruit (and go through the entire digestive tract), for the seeds to then be able to germinate. The germination rate increases drastically after having gone through the gut of a cassowary for example.
All in all, this means that whilst it may be possible for a particular species to survive outside its current range, it cannot effectively disperse to these locations. All of these intrinsic factors may limit where a certain species can inhabit.
3. Gives a sense of place
Homogenisation of urban flora is already happening in our cities. Around the world, one city after the next. Its boring. For me this is bordering on depressing. The reason you travel to different places is to see new things, experience new cultures, gain new perspectives. Learning about the local flora and fauna is all part of this. It should be no different to meeting the local people.
Endemic species can provide a distinct identity to a given place. This is important for humans, and in my opinion, an undervalued attribute.
This is important to humans not only in a connection to the land, spiritual way, but also in a very practical "where am I?" sort of way. You know where you are just based on the plants and animals around you. You start gaining this sense of 'place'. What better way-finding marker is there than observing an endemic plant or animal? - that itself has evolved to live in the very place that you currently are.
In a very rudimentary sense, humans need differences in our environment to navigate. I experienced this myself:
During my honours year, I was driving on the southern side of Winton Wetlands (previously Lake Mokoan), deciding on what sites to use for my research project. I quickly reached a pinpoint drop on my google maps. When I stepped out of the car I was surrounded by walls of Cassinia sifton (a native, quick growing coloniser species). I was completely disorientated. I didn't know the way out. I didn't know which way I came in, which way was north, south, east or west. All I knew was up and down. There was no other plant. Just Cassinia sifton, bare ground and sky.
The homogeneous monoculture in front of me was due to the fact where I was standing had been underwater from 1971-2010. Only recently vegetation returned. Elsewhere there were dead trees, but none here.
You could argue me getting lost in the sifton' was due to a lack of biodiversity and not endemic species. However a homogeneous biodiverse site can be just as hard to navigate as a homogeneous monoculture site. In terms of navigation, Alpha diversity - the total number of species at a site, matters less than the beta-diversity - the difference in species composition between sites, or the 'species turnover'. This 'sense of place' is able to occur, and greatly benefited by the presence of endemic species across a landscape. Endemic species are fundamental to, if not the basis of beta-diversity.
I am getting stuck in the weeds here, but what I am trying to say, and the whole point of this Cassinia sifton story is that wayfinding is much easier when different species are found in different places.
This is an argument I rarely hear used as to why it's worthwhile to control invasive species. Invasive species not only destroy the ecological communities that have evolved for eons, outcompeting endemic species, reducing the biodiversity of an area, but they also threaten our very own sense of place.
Of course wayfinding and navigating is much harder in the cities and suburbs, where we have cleared almost all nature around us, so we rely on signage and god forbid google maps.
Conservation naysayers may not care about the fact endemic species are found nowhere else in the world, or the insights into evolution, but what they do care about is their own identity and saying they are from a certain town, region or place. People derive so much of their own identity from this. Why not extend this appreciation to all the plants and animals that are in your own backgarden? Especially to the endemic ones that can only be found in your backgarden.
Okay, now that's all explained
I hope at a party I will be able to explain why I like endemic species. Probably not.