Conservation  Ecology and Restoration Ecology

History of Earth

Hank Green 

(Source: http://open.163.com)

Conservation Ecology and Restoration Ecology

Hank Green

(Sourse:http://open.163.com)

(Chinese and English subsitles:韩子威)

For the past 12 weeks,we have been investigating our living planet together and learning how it works on many levels,how populations of organisms interact,how communities thrive and ecosystems change ,and how humans are wrecking the nice perfectly functioning systems Earth has been using for hundreds of thousands of years.And now it is graduation day!,this here is like the commencement speech,where i talk to you about the future and our role in it,and how what we are doing to the planet is otally awful,but we are taking steps to undo some of the damage that we have done.So what better way to wrap up pur series on ecology than by taking a look at the growing fields of conservation biology and restoration ecology.These disciplines use all the kung fu moves that we have learned about in the past 11 weeks and apply them to protecting ecosystem and cleaning up messes that we have already made .And one of the main things they teach us is that doing these things is difficult,like in the way that uncooking bacon is difficult.So let is look at what we are doing,and try to uncook this unbelievably large pile of bacon we have made!

   Just outside of Missoula,Montana,where i live,we have got a Super found site.Not superfun...superfound.A hazardous waste site that the government is in charge of cleaning up.The mess here was made more than a hundred years ago,when there was a dam in the Clark Fork River behind me called the Milltown Dam.This part of montana has along history of copper mining.and back in 1908,there was humongous flood that washed about 4.5million cubic meters of mine tailings chock full of arsenic and toxic heavy metals into the clark fork river.And most of it washed into the reservoir created by the milltown dam.I mean,actually it was lucky that the dam was there.it had only been completed six months before.or the whole river system, all the way to the pacific Ocean would have been a toxic mess.As it happened,though,only about 160 kilometers of the river was all toxic messed up.A lot of it recuperated overtime,but all that nasty hazardous waste was still sitting behind milltown dam,and some of it leached into the groundwater,that started polluting nearby residents wells.So scientists spent decades studying the extent of the damage caused by the waste coming up with ways to fix it.And from 2006 to 2010,engineers carefully removed all toxic sediment as well as the dam itself.Now,this stretch of the Clark Fork river runs unimpeded for the first time in over a century,and the restored area where the dam used to be is being turned into a state park.Efforts like this show us conservation biology and restoration ecology in action.

   Conservation biology involves measuring the biodiversity of an ecosystem and determining how to protect it.In this case,it was used to size up the health offish population in the Clark Fork river.which were severely affected by the waste behind the dam.and the dam blocking their access to spawning ground upstream,and figuring out how to protect them during the dams removal.Restoration ecology,meanwhile,is the science of restoring broken ecosystems,like taking an interrupted,polluted river and turning it into what you see taking shape here.there do googer,fix it up sciences are practical rather than theoretical,by which I mean,in order to fix something that is brokrn,you have a good idea of whats making it work to begin with.If something was wrong with theexpansion of the Universe,we would not be able to fix it because we have no idea,at all,what is making all that happen.So in order to fix a failing ecosystem,you have to figure out what was holding it together in the first place.And the glue that holds every ecosystem together is biodiversity.But then of course,biodiversity can mean many different things.So far we have generally used into mean species diversity,or the variety of speciesin an ecosystem.But there are also other ways of thinking about biodiversity that help conservation biologists and restoration ecologisysts figure out how to save species and repair ecosystems.In addition to the diversity of species,ecologists look atgenetic diversity within a species as a whole and between populations.Genetic diversity is important because it makes evolution possible by allowing a species to adapt to adapt to new situations.like disease and climite change.

   Another meaning of biodiversity, however, is ecosystem diversity, or differences between different ecosystems within the same area.For example, a large ancient forest can carry several ecosystems, such as wetlands, mountains, and water environments.As we talked about in ecological succession, the more individuals with different functions, the more resilient the region as a whole is.These understandings are very important.To figure out how to fix this broken ecosystem.But how do conservation biologists try to figure out how to hit the nail on the head?There are a number of ways to solve this problem. One is called small-population conservation, which focuses on species with very small populations and tries to help increase population size and genetic diversity.Low population size and low genetic diversity are a death knell for a species.In fact, they depend on each other so much that a single problem can affect the whole, leading to a slow extinction of a species.Look, when a small population grows to the point where it has to inbreed, it causes genetic drift, which shifts the overall genetic makeup, and that leads to a decrease in diversity, which in turn leads to lower reproductive rates and higher mortality, which ultimately makes the population very rare.There's a term for this terrible dynamic, the extinction vortex.The next step is to figure out how small a population is.Ecologists calculate the minimum number of living populations, that is, the minimum number of individuals that can sustain the survival and reproduction of a population.To get that number, you need to know the true breeding population, like the royal national park grizzlies, and you need to find out all the family history of grizzly bears you can.Where they were, how long they lived, which bears were most fertile, how long they took to conceive and give birth, and so on and so forth.With all this information gathered, ecologists were able to calculate the Numbers and figure out that for Yellowstone grizzlies, if there were a population of 90 bears, there was a 95 percent chance that they would live for 100 years, but if there were 100 bears in the population, there would be a population of 200 years.The thing to note here is that ecology involves a lot of math, so if you're interested in it, learn it.This is a small population protection method.Another way to protect biodiversity is to target declining populations.No matter how big it is.The cup is called population decline conservation, and it involves answering a series of related questions, such as what is causing a species' population to plummet.First, you have to measure whether the population is actually declining.And then you have to get the Numbers of the population at different stages in history, and the environmental factors at that time.Finally, you have to analyze what caused the drop and figure out how to fix it.In fact, the dam is a good example.In the winter of 1996, the government had to release water urgently because a large ice floe floating on the river threatened to destroy the dam.But when the dam was opened to release water, much of the toxic sludge flowed out, causing copper levels in the lower reaches of the river to soar 43 times above national standards.About half of the fish downstream died.The population the researchers monitored has been declining since then.This data is very helpful in making decisions about what to do with the dam, because we know what happened to the fish before and what happened after the release of the toxic sludge, so making a decision to remove the dam as soon as possible is the best solution, rather than leaving it alone and causing water pollution in 1996.This is where conservation biology and restoration ecology are linked.Restoration ecology is a challenging branch of conservation ecology.It offers possible solutions to ecological problems.It's kind of like a time machine, although you can't recreate the natural environment exactly the way it used to be.But you can at least fix what went wrong and help properly rebuild a portion of the ecosystem that is needed to function properly.It takes a whole set of strategies, for example, the Milton case, where the structural recovery is basically destroyed, all those problems that humans cause.These problems in this case are the dam and the toxic sediment behind it.The follow-up was to reconstruct the natural structure, in this case, the meandering river and vegetation, based on historical data.Another strategy is bioremediation, which temporarily introduces other organisms to help remove toxins, such as bacteria that eat waste and plants that filter heavy metals out of contaminated soil.Researchers are even studying fungi and bacteria as bioremediation methods to deal with the oil spill in the gulf of Mexico.However, another invasive method is called biological additives.This is not to remove harmful substances, but to add a living thing to the ecosystem and rely on it to restore the missing substances in the system.Legumes, albizia trees and lupines are often used to replenish the soil with nitrogen.Many have been destroyed by mining or overfarming.Ecologists sometimes add mycorrhizal fungi to help newly grown plants stabilize like native plants.But we're just human beings, not that smart.Even though we've been evolving for millions of years.Sometimes, we screw things up.For example, one might want to introduce an invasive species into one place to wipe out another, often resulting in the two plants living in harmony, causing the ecosystem to collapse even more rapidly.The introduction of the sea toad to Australia in the 1930s to control the beetle was a perfect example of how not to do it.Not only are they everywhere now, but they are poisonous, poisoning the native dingo that tried to eat them.So, you know, I had this idea that after we spent a couple of weeks talking about ecology, I came to the conclusion that it's easier to protect ecosystems than to repair them.Because we know a lot about what makes ecosystems work, if we spend more time protecting them, our kids won't spend as much time cleaning them up.and running the risks of getting it wrong.Because as we all know,the sad fact isuncooking bacon is impossible.but we can eat it.Thank you for joining me on this quick three-month jaunt through the natural world,I hope it made you smarter not just in teems of passing your exams.but also in therms of being a homo-sapien.that inhabits this planet more wisely.And thank you to everyone who helped us put these episodes together,our technical director Nick Jenkins,our editor Caitlin Hoffmeister,ourwriters Blake DePasino,Jesslyn Shields and myself,our sound designer Michael Aranda,and our animators and designers Peter Winker and Amber Bushnell,And good news is there is more rash course coming ay your soon.If you have any questions or comments or ideas ,we are on Facebook and Twitter,and of course down in the comments below.we will see you next time.