first_imgAnimals, Environment, Evolution, Extinction, Featured, Islands, Mammals, Mountains, Protected Areas, Rainforests, Research, Rodents, Wildlife Researchers have identified the smallest-known island where multiple species of mammals evolved from a single founding species. The Philippine island of Mindoro is the size of Yellowstone National Park and host to four species of earthworm mice.Genetic analysis indicates all members from these four species descended from just a few individuals that rafted to Mindoro from a neighboring island millions of years ago.Three of the species are endemic to Mindoro, and the researchers believe they evolved on different mountains. The study’s findings highlight the pivotal role mountains can play in speciation, and provide evidence that evolution can occur even in small areas.The researchers say this underlines the importance of protected areas not just for species preservation, but for species emergence as well. The apparent success of such a small founding population may also give hope for species currently hovering on the precipice of extinction. Evolution takes time and space. Enough time needs to pass for genetic differences to crop up in a population of animals and make them distinct from their forebears. And enough space is needed to stop interbreeding between populations from ironing out these differences.But just how much space is needed for species to diversify? Scientists have been puzzling over this question for decades, and it’s one that has taken on increasing importance as human-driven habitat loss constricts the ranges of the world’s wildlife.In their quest to solve this mystery, a team of researchers from institutions in the U.S. have been scouting the globe for the smallest island that supports multiple lineages of mammals evolved from a common ancestor. And in a new study published recently in the Journal of Biogeography, they describe such a place – an island in the Philippines with a unique array of worm-eating mice.From one species to fourAt around 10,000 square kilometers (4,000 square miles) Mindoro is about the size of Yellowstone National Park in the U.S. and represents a big step down from the previous record-holder, Luzon. Also in the Philippines, Luzon is the country’s largest island and about 10 times the size of Mindoro, which lies just across the Verde Island Passage strait.Montane rainforest on Mindoro. Photo by L.R. Heaney / The Field MuseumWhen the researchers surveyed the mammals of Mindoro’s forests, they discovered four distinct species of earthworm mice. Nested within the genus Apomys, earthworm mice are found only in the Philippines and get their name from their favorite food.“The mice we looked at in this study are all members of the ‘earthworm mouse’ group Apomys—they love earthworms, but they also eat seeds and fruits,” said Lawrence Heaney, Negaunee Curator of Mammals at Chicago’s Field Museum and co-lead author of the study. “They’ve got big dark eyes, great big ears, long soft fur, white feet, dark tails —they’re very pretty little mice.”One of these four species is also found on Luzon, but the other three proved to be new to science when the team analyzed their DNA. These three species appear to only live on Mindoro and the study’s findings indicate they evolved from a small group of mice that travelled over from Luzon sometime between 1.5 and 2.4 million years ago.Part of the research team that surveyed Mindoro. Photo by D.S. Balete / The Field MuseumBut how do tiny mice become seafaring colonists? Easy, says Heaney. They could’ve hitched a ride on some flotsam during a typhoon.“Given the strong winds and relatively short distances between islands, it is inevitable that on rare occasions, a tree or log with some mice living in it will be floated out to sea and blown across from Luzon to Mindoro,” Heaney told Mongabay. “It could take as little as one day, but certainly not more than a few days – it is not very far.”Still, while it’s a quick trip from Luzon to Mindoro, the study found all four species on the island likely descended from one small group, indicating Mindoro was probably colonized by earthworm mice just the one time. Heaney said this lucky founding group was greeted by “unlimited resources,” allowing them to quickly proliferate “from a few to dozens, to hundreds to thousands to the current hundreds of thousands.”These descendants ranged far and wide over Mindoro with some getting up into the island’s mountains. It’s in these mountains where the researchers found the new species, suggesting that mice there became isolated from lowland populations, which ultimately allowed them to evolve into distinct forms.The researchers think that the fact this diversification happened on mountains may mean geographic features may play a bigger role in evolution than area alone. And not just in the Philippines. Take, for example, the Eastern Arc Mountains that run down eastern Africa. Capped with isolated forests, each mountaintop is home to unique species found nowhere else in the world.“This study changes how I think about conservation,” Heaney said. “When we think about how to design protected areas, we need to think about the topography of the Earth, not just a flat map. The fact that these mice evolved on their own separate mountains within a limited geographic area tells us that mountains are important.”One of the species of earthworm mice new to science, this one found on Mt. Abra. Photo by D.S. Balete / The Field MuseumThe presence of mountains is so influential for evolution that Heaney said it could perhaps even be used as a proxy for speciation.“So, once we figure out how big an island needs to be to have two large, fairly old mountains, we may know the minimum size of island [for mammal diversification],” Heaney said.The researchers are now focusing their search for still-smaller islands on places where there are at least two mountains; they’re currently eyeing a number of possibilities in Indonesia.Conservation implicationsAccording to Heaney and his team, the diversification of mice on an island the size of a national park underlines the importance of protected areas not just for species preservation, but for species emergence as well.“As human population continues to expand, what’s going to happen to everything else? How will new species be able to evolve?” Heaney said. “This project is a step forward in being able to answer that.”The study may also have implications for the conservation of critically endangered species with small remaining populations. When an animal’s population size becomes very reduced, scientists worry about a phenomenon called “inbreeding depression,” which happens when close relatives breed so many times that harmful genes normally rare in a healthy population become common. These genes can express themselves in ways that can harm an animal or make it unable to reproduce, and ultimately may reduce the fitness of a population and even bring about its extinction.Conservation geneticists have long argued over how many individuals are needed to maintain enough genetic variability in a population to keep it from collapsing due to inbreeding depression. In the 1980s, researchers set that number at 50. However, conservation successes with populations that initially numbered fewer than 50 have given scientists hope that species with just a handful of individuals remaining might be able to come back from the precipice of extinction.Scientists think there may be just 30 wild Sumatran rhinos (Dicerorhinus sumatrensis) remaining in the world today.The study’s results indicate just a few earthworm mice made it to Mindoro and went on to beget four healthy species comprising hundreds of thousands of individuals. So how did they escape inbreeding depression? Heaney thinks it may have something to do with how quickly they proliferated. With lots of food and little competition, the initial population likely didn’t suffer many diebacks, which helped safeguard what little genetic variation it had. Still, he said, their survival may have been touch-and-go for a while until new mutations arose and strengthened their diversity.​Heaney said a similar option might be possible for other species – if certain conditions are met.“The lesson that I take from this is that when a sudden, rapid, massive decline in a population occurs (in this case, due to a colonization event), IF the population is then able to grow to larger numbers very rapidly, and to have enough resources to maintain a large population over enough time to accumulate new genetic variation, they may do perfectly well,” Heaney said. “Those are pretty stringent requirements, but it is essentially the scenario that is the hope of many of the captive breeding programs for endangered species that are currently in operation.“It is a long shot, but it is sometimes the best one we have.” Banner image of an earthworm mouse on Mindoro’s Mt. Halcon. Photo by L.R. Heaney / The Field MuseumFEEDBACK: Use this form to send a message to the editor of this post. If you want to post a public comment, you can do that at the bottom of the page. Article published by Morgan Erickson-Davis Popular in the CommunitySponsoredSponsoredOrangutan found tortured and decapitated prompts Indonesia probeEMGIES17 Jan, 2018We will never know the full extent of what this poor Orangutan went through before he died, the same must be done to this evil perpetrator(s) they don’t deserve the air that they breathe this has truly upset me and I wonder for the future for these wonderful creatures. So called ‘Mankind’ has a lot to answer for we are the only ones ruining this world I prefer animals to humans any day of the week.What makes community ecotourism succeed? In Madagascar, location, location, locationScissors1dOther countries should also learn and try to incorporateWhy you should care about the current wave of mass extinctions (commentary)Processor1 DecAfter all, there is no infinite anything in the whole galaxy!Infinite stupidity, right here on earth.The wildlife trade threatens people and animals alike (commentary)Anchor3dUnfortunately I feel The Chinese have no compassion for any living animal. They are a cruel country that as we knowneatbeverything that moves and do not humanily kill these poor animals and insects. They have no health and safety on their markets and they then contract these diseases. Maybe its karma maybe they should look at the way they live and stop using animals for all there so called remedies. DisgustingConservationists welcome China’s wildlife trade banThobolo27 JanChina has consistently been the worlds worst, “ Face of Evil “ in regards our planets flora and fauna survival. In some ways, this is nature trying to fight back. This ban is great, but the rest of the world just cannot allow it to be temporary, because history has demonstrated that once this coronavirus passes, they will in all likelihood, simply revert to been the planets worst Ecco Terrorists. Let’s simply not allow this to happen! How and why they have been able to degrade this planets iconic species, rape the planets rivers, oceans and forests, with apparent impunity, is just mind boggling! Please no more.Probing rural poachers in Africa: Why do they poach?Carrot3dOne day I feel like animals will be more scarce, and I agree with one of my friends, they said that poaching will take over the world, but I also hope notUpset about Amazon fires last year? Focus on deforestation this year (commentary)Bullhorn4dLies and more leisSponsoredSponsoredCoke is again the biggest culprit behind plastic waste in the PhilippinesGrapes7 NovOnce again the article blames companies for the actions of individuals. It is individuals that buy these products, it is individuals that dispose of them improperly. If we want to change it, we have to change, not just create bad guys to blame.Brazilian response to Bolsonaro policies and Amazon fires growsCar4 SepThank you for this excellent report. I feel overwhelmed by the ecocidal intent of the Bolsonaro government in the name of ‘developing’ their ‘God-given’ resources.U.S. allocates first of $30M in grants for forest conservation in SumatraPlanet4dcarrot hella thick ;)Melting Arctic sea ice may be altering winds, weather at equator: studyleftylarry30 JanThe Arctic sea ice seems to be recovering this winter as per the last 10-12 years, good news.Malaysia has the world’s highest deforestation rate, reveals Google forest mapBone27 Sep, 2018Who you’re trying to fool with selective data revelation?You can’t hide the truth if you show historical deforestation for all countries, especially in Europe from 1800s to this day. WorldBank has a good wholesome data on this.Mass tree planting along India’s Cauvery River has scientists worriedSurendra Nekkanti23 JanHi Mongabay. Good effort trying to be objective in this article. I would like to give a constructive feedback which could help in clearing things up.1. It is mentioned that planting trees in village common lands will have negative affects socially and ecologically. There is no need to even have to agree or disagree with it, because, you also mentioned the fact that Cauvery Calling aims to plant trees only in the private lands of the farmers. So, plantation in the common lands doesn’t come into the picture.2.I don’t see that the ecologists are totally against this project, but just they they have some concerns, mainly in terms of what species of trees will be planted. And because there was no direct communication between the ecologists and Isha Foundation, it was not possible for them to address the concerns. As you seem to have spoken with an Isha spokesperson, if you could connect the concerned parties, it would be great, because I see that the ecologists are genuinely interested in making sure things are done the right way.May we all come together and make things happen.Rare Amazon bush dogs caught on camera in BoliviaCarrot1 Feba very good iniciative to be fallowed by the ranchers all overSponsoredlast_img read more