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Listen to this and more in the podcast of the International Commission for the Protection of the Alps. www.cipra.org.org. Port slash podcast. Welcome to a new edition of the CIPRA podcast with Veronique Achibaneek at the microphone.
Over the past three years, the B AWA project has inspired communities throughout the Alpine Arc to protect wild beasts and honeybees and thereby improving the livelihoods of these important pollinators. The online B CON friends, let's be together at the end of April, marked the conclusion of the project. After B-friendly conversations with participants from across the Alps and a virtual flight through the Alpine Arc with inspiring presentations from selected project communities, we listened to a keynote on biodiversity by Dr. Severniel from the University of Frankfurt.
Listen now to a shortened version of the keynote with the title, Treasure Island Imperial, insights from Oceonic Islands and the relevance for the Alps and other mountain systems. And find out what mountains and islands have in common. At the Biodrome study, the distribution of living beings in space and time, and I use islands as model systems to do this, but the relevance of the things we find in islands often can be transferred to other larger systems on the continent. But islands are good living laboratories, as you said, to study the general processes that we find in nature on earth.
So, but the first question is actually what is an island? And of course, we all maybe have in our mind some kind of tropical dream island like this one with white sandy beaches, coconut trees, tropical lush green, tropical rainforest, a blue lagoon, maybe a cocktail in one hand and a surfboard in another hand. And these islands exist, but from an ecological and biogeographic perspective, islands can be much more because isolated habitats exist also on the continent. For example, here if you look at the satellite image from Kilimanjaro, it's this Kilimanjaro peak and it's neighboring Kilimanmio in Tanzania.
We can see already this from the colors of the imagery that especially the Alpine zone here above 3000 meters is something like a sky island in a sea of savannah. So, we have very different environmental conditions up here in the Alpine zone that we have in the low elevation of savannah here. And therefore, mountains are also termed sky islands because many processes, and that's what we'll be showing, many processes that lead to biodiversity, are comparable between islands and mountains. And of course, I mainly work on real islands.
So, I'd like to share some facts about islands in general. Islands are actually quite irrelevant in terms of surface area. They only cover about 6% of the global surface area. Even though there are about 340,000 islands which worldwide, countries like Indonesia alone has already 17,000 islands of which 6,000 islands are inhabited.
The largest island is Greenland. It has about 2.1 million square kilometers. Why is this debated? Because actually Greenland is several smaller islands connected by the ice cap.
So the next larger real island is New Guinea, just north of Australia. And we have also a very strong range in geological age. Some islands are quite old. Like Madagascar is 150 million years old.
And other islands are just a few years or decades old, like the island Surtian off the coast of Iceland, which was born in 1963, due to volcanic activity. Also islands can range dramatically in their elevation range. Some atolls are only a few centimeters, maybe two, three meters above sea level, let's say, the melodies, for example, are basically just a few centimeters above sea level. But some islands reach more than 4,000 meters, for example, Hawaii or Taiwan or Borneo, or even New Guinea, the biggest island is also the highest island.
The most peak Mount William is 4,500 meters high and even has a glacier ice cap on top, which is quickly melting away, but it has one. Islands also inhabit about 10% of the human population, but interestingly they harbor also 27% of the languages. So we have this proportionally high amount of a number of languages on islands, probably due to the isolation also in cultural sense. And about 25% of the world's nations are island nations.
So this could be a force to reckon with it in the political arena if islands would choose to do this, but they obviously don't at the moment at least. Most of the money from my talk is islands harbor 20% of the global biodiversity, but only cover, like I said, 6% of the Earth's land surface area. So we have just this proportion at high contribution of islands to global biodiversity, about four times as much biodiversity as expected from the land area itself. So islands are real hotspots of biodiversity, and the reason why we have white biodiversity is so high is not because islands themselves are species-rich, actually they're quite species-poor.
Each island itself is quite species-poor, but we have many endemic species on islands, which makes each island unique in a sense, which is because it has unique species that only occur there. But I'd like to talk about this topic, endometism, because it's a little difficult and not clear to everyone. At this point, in a lecture to students, I would ask them how many species are endemic on Earth. And then they would say something like, oh, I don't know, 100,000 or 1,000,000 or 10,000 or something like that.
And of course, this is a trick question because as far as we know, all species are endemic to Earth. So far, we haven't found giraffes or peach trees on Mars. The Mars rover hasn't found any. If the Mars rover that is currently up there would find the giraffe on Mars, then the giraffe wouldn't be endemic to Earth anymore, but would have a wide distribution.
So endometism is always dependent on the reference system. And in this case, the reference system is Earth. And this is for biographic terms, not very sensible, not very helpful, because it's much too large. If we look down at smaller systems, for example, at the Alps here, I found some nice examples of endemic species in the Alps.
The Alps could be our reference system. So these species here, like this one here, people at Leoni, is an endemic species to the maritime Alps. So even a smaller region, and it's actually only found in two valleys in the maritime Alps. So it's a very local endemic with a very range-restricted distribution.
And this is more what we consider endometism. Or another example is here, Saxiflaga Stiriaca, which is an endemic to Stiria, as the name already implies, it only occurs in the region of Stiria. And yeah, it has a very small distribution, and only found in the neither the Taewang there, so a very local endemic species too. If we look at this little more distribution of endemic species, a little more closely, we see that endemic species, this is for Austria, but this is probably also true for the rest of the Alps.
Most endemic species occur at like these mid to high lemmations between 1600 and 2000 years. So this is about the transition zone between the sub-outline forests and the alpine meadows, and it's obviously some ecologically important region for endemic species. If we go to the islands, islands are much clearer to define the borders for the Alps or for many other mountain systems. It's quite difficult to define where the Alps actually begin, where is the border, and where do the Alps end, but for islands it's much clearer.
We have the coastline, which differentiates between the habitable area, so the island and the habitable ocean. And what is the reason for this, the explosive diversity of island species, where we have within a genus many different species, in how to think different parts of the islands are different environmental regions in the island. What we term adaptive radiation is a process leading to the strong diversity of the island of the island, but it also occurs on mountain systems as well. Now this is a radiation process, but it also talks about how endemism is distributed on islands spatially.
An important part is the elevation of gradients. And if we look at here, and the elevation of gradients also stands for isolation. If we look at this map here for the other Canary Islands in the Atlantic Ocean, we can see that the nearest coastal system is only about 100 kilometers away from the nearest island. But if we go to the alpine system above 2,000 meters here depicted in this reddish-brown color, the nearest alpine system on the continent is more than 700 kilometers away.
So that means with increasing elevation, we have increasing isolation, which reduces gene flow between populations, and therefore might increase speciation, and that's the production of endemic species. For all these different island systems, we find a general pattern that is the increase of the percentage of endemic species with elevation. And we interpret this as an increase of isolation with elevation, which leads to higher diversification and speciation rates. So more endemic species are created due to evolutionary processes in higher elevations than in lower elevations.
And this is not only true for islands, this is also true for mountain systems around the world. So this is a very general pattern that was found on islands, but it's also transferable to mountains. But another aspect about endemism and speciation is climate, and climate, as we know, is non-stationary, it's quite dynamic, it changes to time, and it has long lasting effects on biodiversity, how biodiversity is generated. So when we have temperature change, we have sea level change.
And of course for islands, the sea level changes are more relevant. We have during the last spatial maximum, the LGM, so it was about 20,000 years ago, the sea level was 120 meters lower than today, which means, of course, that some islands that are now isolated were connected to each other or to the mainland, or were just less isolated from the mainland than they are now. So through time, we have changes in connectivity and isolation for islands. And the same is true if we look at the temperature change, which is more relevant for mountain systems, if we look at the alpine system in mountains above the tree line, it has fluctuated up and down the mountains along with these temperature changes that we have seen in the past 800, even millions of years.
So alpine systems have been more isolated during the warm phases and had more connectivity when they were lower during the cold phases. And this has led to fusion and fission of the alpine systems within the mountain system. So what we see is temperatures at sea level have dramatically changed throughout 800,000 years. So we're in a warm period of so-called interglacial, which is rather the exception than the norm.
And that means that most species that are about a couple hundred thousand years old, these are the timescales for evolutionary processes, 100,000 to a million years old, they evolved under much cooler ice age conditions that were dominant in the last several millions of years. If we look at this from a perspective from a spatial perspective, I'd like to show you a graph here with the Alps and one with the archipelago of Hawaii. And it shows the spatial distribution here for the alpine system, so the system above the tree line. During different stages here, the glacial stage, the interglacial stage and also future stage with 2% to degrees temperature increase.
And what we see is in the glacial stage, the alpine system was restricted to the borders of the peaks in the outer part of the alps were available habitat while the central parts of the alps were covered with large ice shields. The current interglacial, we see this also island-like archipelago-like behavior of the alpine system where we have different peaks functioning as island-like structures. And if we look at the future here, 2 degrees increase, we see that the alpine area, the area of the alpine system will dramatically decrease in area. So we have these past changes have led to expansion and contraction of suitable habitat, triggering these diversification processes, as we see in the past.
Under isolated conditions, we have higher speciesation rates because of restricted gene flow than under high connectivity conditions. And that's why very similar mountains and island service species pumps because of these fluctuating conditions, they're always constantly pumping out new species, I mean, over evolutionary time, of course. And that's why their contribution to global biodiversity is so important. And what we also see is this possible dramatic contraction of suitable habitat for the next century under the current climate change that we see, which is, of course, an anthropogenic climate change.
Now we're coming to the threats to island biodiversity and basically we can end endemic plant species and islands. I work with plants, but many of these threats also are relevant for other taxonomic groups like insect or mammals or birds, for example. Basically, there are three main threats to island endemic plant species and invasive species, habitat destruction and over-exploitation of habitat and also down more increasingly also climate change. If we look at a global analysis of how climate will change, probably change on islands within the next century due to anthropogenic climate change, we see that for temperature, which is one part of climate, we see a general increase, which is, of course, clear our planet's warming.
So while islands warm, maybe not as strongly as a continent because islands are buffered by the ocean in temperature. That's why they have a very equalized climate throughout the year, little system seasonality, with precipitation is a little different. If you look at precipitation changes in the next decades, we see this diverging pattern, so an increase in variation in precipitation. And then the general pattern is drier islands will become drier and wet islands will become wet.
So this was a global perspective on climate change, but how will this actually affect species on the islands? And so to see how this will affect species, for example, for my island of life, where I work on species distribution modeling approach, where we model the distribution of all endemic plant species under current climatic conditions and under future climatic conditions. And then we kind of overlaid their distribution and made this map of change in species richness of endemic species. So species richness will decrease in many areas, especially in the coastal areas here, right coastal areas, but also particularly in the alpine system on the highest part of the mouth.
So alpine species are particularly threatened here, and this makes sense because alpine species, they already occupied the highest elevations of the island or mountain peak, this is the same as true also for mountains. And when climate warms, they have to move upwards, but eventually there's no more room to move upwards because they're only at the peak because species from lower elevations will push them over the top, which of course, in this case might lead to extinction. Of course, it's difficult to predict extinction or we can't predict extinction, but what we find is three of the five, what we call biggest losers are alpine species. And we define biggest losers as species that lose 100% of their climatic suitable area.
And this of course points in the very strong direction that these species will be threatened by extinction in the near future. Now to look at the mountain systems here, also the alpine, also among them, this nice study in nature from 2018 looked at different mountain systems in the Alps, from the Pyrenees to the Alps to the scans to Swalbald island. And it looked at how climate change has already affected mountains in the last 140 years or more. And how can they do that?
And I used, and it's a very nice approach, I used botanical studies that were 100 or 120, 140 years old and went out there again in these survey same areas to see how species composition and species which has changed over this long time period. But the question is how do you find a vegetation survey area that was surveyed 120 years ago when they didn't have any GPS or anything like that. And the brilliant idea was that these people already back then, they loved hiking up mountain peaks and studying the flora on the mountain peaks. And these mountain peaks of course are still here.
Nowadays they haven't changed much, but so we can go back to these mountain peaks and survey the flora and then compare the current survey with the past survey. And what we see is two things, in general we see the hairs going in the dramatic increase of temperature in the last 120, 140 years with a strong increase in the last 20 to 30 years. So there has been an acceleration in temperature change. And this kind of is very strongly, very nicely mirrored in the changes in species which has increased and then dramatically accelerated in the last 20 to 30 years.
So what does this mean for mountain peak species? And like we saw before, in high elevation we find we have a high percentage of endemic species and if species from the lowlands are moving upwards into the areas where the endemic species usually occur, they will start to out-compete these high-levelish specialists and the low elevation or lower elevation generalists will replace them. So the mountain peaks might lose their uniqueness in the future, which is of course a dramatic loss for a mountain biodiversity. In general what we see is that, and I'm sure you all know this, we're in the middle of this global biodiversity crisis and what we have seen is that extinction rates have strongly increased especially in the last 100 years.
For all different kinds of taxonomic groups, amphibians, mammals, plants as well which are not shown here and extinction rates are much higher than the natural extinction rates would be. And the IPBEST here has estimated that the International Governmental Panel on Biodiversity and Ecosystem Services has estimated that globally about 1 million species are threatened of extinction. And depending on how you count global species which is because we don't know how many species really occur on Earth yet, that's about 5 to 10% of all species worldwide that are threatened now of immediate extinction. And of course this is not fine, this is something that we all are working to stop.
Just to see what dramatic effects, or what dramatic effects, large-scale effects of anthropogenic biodiversity loss has, I'd like to show you this example of the bird farm of New Zealand where a colleague of mine studied how the European and pre-European colonization has led to widespread extinctions. The Maori already led several species like the Moa, the most extinction or the highest eagle here, the largest eagle in the world. These species already went to extinctions pre-European colonization and then when the Europeans found out many other species went extinct as well. And what my colleague did is he looked at the current species' riches and the past species' riches for the bird farm and then he let evolutionary models run and to see how long it would take for the current species' riches to go back to its pre-human species' riches.
And what he finds is that this is really astonishing, it would take 50 million years of evolutionary processes, natural evolutionary processes to produce a comparable pre-human diversity in the bird farm. 50 million years, if we go back 50 million years, we're almost back at the dinosaur age. And if we go 50 million years in the future, there won't be any Homo sapiens anymore. Homo sapiens, our species, is only 250,000 years old.
So we have these irreversible effects on biodiversity that have already happened, and we're still losing biodiversity due to anthropogenic impacts. So we see very long-term impacts on the diversity which are basically for our species, irreversible because we won't be able to change these things. Well, for example, climate change is something that we could change in a few generations. So I get to my last part because I'm learning a panel a little bit.
Island diversity is under threat. Even though islands only have about 20% of the species, 50% of the endangered species are island species because they are range restricted because they are genetically impoverished and 80% of the extinct species, for example, is dodo here that we've already recorded are from islands. And 85% of these extinction are linked in basis species are very important for the loss of species on islands. For example, this species is very heavily huge European rabbit, my kids like to feed rabbits, for island scientists, they're plantulas.
They're one of the most dramatic plantulas on islands because European rabbit is one of the 100 worst in basis species worldwide. Okay, to sum up a little take-home message here, I'd like just to say, and what we see is islands and mountains are surprisingly similar. I'd just like to throw in the term of sky islands again that we use often for mountains and the processes leading to biodiversity and optimism. Both islands and mountains are irreplaceable hotspots of global biodiversity.
That's a very good reason to protect the biodiversity here and in mountains and islands. But we also see that biodiversity, and I'm sure you also all know this for your mountain systems, is under pressure. And the main pressures are habitat destruction, climate change, invasive species and over-exploitation. This is what I know for islands and I assume this is also true for mountain systems.
That was a shortened version of the keynote, Treasure Island in payroll, insights from oceanic islands and the relevance for the Alps and other mountain systems, by Sivir and Il from the University of Hanford. He was the keynote speaker at our online bee conference, Let's Be Together. If you want to know more about Be Aware and CD activities from the project communities, visit our website vv.seapra.org. Or visit the Be Aware blog, vvv.beaware.blog.
Sivir implemented Be Aware in cooperation with the community network aligned in the Alps and the Alpine Town of the Year Association. The project was funded by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety and other third-party sources. Thank you for listening and always stay aware. You heard Wernie Kafirbenik at the microphone.
Goodbye and see you next time.