Have been described scientifically. There are a lot yet to be discovered. Many of these discoveries could be made in tropical rainforests, where it is thought that over half of the worlds species exist. But we are losing these bastions of biodiversity before we even know whats in them. And tropical biologist bill laurance is learning what impact en amall road can haven their viability. A lot of tree mortality, a lot of deaths. Narror the oceans, too small changes in a fragile coral reef ecosystem can have lasting effects. Ecologist Jeremy Jackson is finding human impact on the worlds oceans could be setting them on a path of drastic change that he calls the rise of slime. Dr. Jackson if the world becomes a world of slime then theres not much room for people. Narrator these studies one on land, the other in water are showing just how delicate ecosystems are and what an Important Role biodiversity plays in their ability to endure. Just over 15 miles from the heart of panama city, and steps away from the panama canal, lies Soberania National park a 55,000acre rainforest that is just one of the many rainforests around the world being studied by tropical biologist bill laurance. Dr. Bill laurance the focus of our research is, essentially how do humans affect tropical rainforests . About 40 million acres of Tropical Forest are being destroyed every year. Thats about 80 football fields a minute and as a consequence we are seeing vast landscapes being denuded of forests. We are also seeing the original rainforest being chopped up into isolated islands or parcels. And this might seem like an ironic place to talk about it here because it seems like such a beautiful area. We are in the heart of panama in Soberania National park but this is probably the future of much of tropical biology, because although it seems like a large area of rainforest over here we have bulldozers knocking down the forest. Over in this direction we have slashandburn farming going on. We have hunters encroaching from all sides of the forest having major impacts on the wildlife communities. This is an island of forest, and its shrinking over time. And so really this is the heart of t question we are trying to get out here. Are these going to be islands of survival or islands of extinction . Yes, youre very cute. Narrator for laurance e importcef the rainforest arose from a lifelong love of animals. Very pretty little bird. Dr. Bill laurance i was one of those kids at just loved animals. And i raised mountain lions and bear cubs, and i was a falconer. I had birds of prey and owls and ferrets and flying squirrels just a whole menagerie that my longsuffering parents put up with. I started working in zoos in the United States. And eventually i just became convinced that its the protection of the natural homes the ecosystems thats really critical. So at that time i decided that i wanted to work on conservation of natural ecosystems. [ speaking Foreign Language ] narrator that desire has taken laurance all over the world. For over 25 years, he has beestudying rainforests in africa, australia, brazil, and at the sthsoni Tropical Research institute in panama. Dr. Bill laurance we do some work here in panama but the amazon and Central Africa where we work are just such hot spots of forest destruction. In the amazon, there is incredible forest destruction for cattle ranching. Theres a huge explosion in soybean farming. Theres massive logging operations. Theres an avalanche of new highways and roads and other kinds of projects which are creating a lot of problems for the forest. We focus on those areas because theyre the most important from a conservation perspective. Narrator often called the lungs of the planet, the worlds rainforests have gone from covering 14 of the earths land surface to 6 over the last 50 years. In addition to providing us with over 20 of the oxygen we breathe these forests are the most biologically diverse habitats on the planet, home to over half of the worlds estimated 60 million species of plants, animals, and insects. Dr. Bill laurance one of the really exciting things about working in tropical rainforests is theyre just such a mystery and theres just so much we dont know about whats here, even just in terms of cataloging the number of species here. Right now we think there are somewhere between maybe 5 million and 50 million species living in the tropical rainforests of the world. We are talking about that rough of reckoning here. And one of the reasons that we have such a vague idea of whats here is the rainforest canopy. Studies that have been done in trapping insects in the canopy have found in many cases that 80 or 90 of the species that they are finding up here are new to science have never before been documented. And if we extrapolate from what we are finding here throughout the tropical world, we are getting numbers like 50 million, which is just an extraordinary number. So this is one of the last great biological frontiers is the rainforest canopy. Narrator and the heart and soul of these forests are the trees. Dr. Bill laurance trees are the foundation of the forest. They form the architecture of the forest. They determine its microclimate. They are the food sources of most things out there. So if you change the tree communities you are really changing the ecology and the habitat for just about everything else. Narrator one way that rainforest tree communities have been changed is through outright destruction or habitat loss. This destruction has broken large rainforests up into many smaller habitat fragments. Laurance is studying the effects of this forest fragmentation. Dr. Bill laurance fragmentation in forest edges affect the rainforest in all kinds of ways. The rainforest under its normal conditions, is a humid and dark and windless kind of environment. Its been surviving, existing for millions of years. And so many, many species have become specialized for these very unique microclimatic conditions. And then you juxtapose that with a harsh, dry, windy cattle pasture and so the conditions are just completely different. Narrator at the forest edge where these two different environments meet, common plant species that are well adapted to the sunny and dry conditions start to take over affecting the overall diversity and structure of the forest. Dr. Sue laurance one of the important mechanisms thats pushing the change in structure are these vines. What the vines do they start to smother trees up near the edge and actually they can kill these trees. And the thing that we are most concerned about with fragmentation and these sorts of structural changes in the edges is that the edges start to encroach into the fragment itself and the fragment starts to shrink in area. Dr. Bill laurance whenever you have an environmental change theres winners and losers. So the vines and other things that like disturbance are doing great. What we are seeing really declining dramatically are the oldgrowth rainforestinterior specialists. Their geographic ranges are collapsing they are becoming much less abundant and they are becoming much more vulnerable to extinction. These are the things that we are really worried about. Narrator as you walk in from the edge of the forest, the difference in e environment becomes obvious. Dr. Sue laurance its a lot darker in here. We are a couple hundred yards from the forest edge now and you can see just what a dramatic change its been a lot cooler, a lot darker. You gothese big forest palm trees, and the forest understory is just generally a t sparser now. We dont have that profusion of vines, and we have got a lot of these sdeloving plants which cant survive on the harsh forest edge. We call thisnvironment in here the core of t habitatragment. And we are very coerned about how much area ore habitat do we have . And what we are really saying is how much area of pristine rainforest is left with aorest fragment . And this is very important to tell what species are going to survive in forest fragments. Is the core habitat big enough to have more than one individual of this palm species . Because some of these species can be very rare there could only be one per acre. So do you need to have 50 acres to have 50 individuals . And will that be enough for that population to survive for couple hundred years . Narrator to discover exactly what the effects of fragmentation are on the rare oldgrowth tree species in the amazon forest the Research Team compares plots along forest fragment edges to plots within pristine forest ars. Bill laurance we have bn studying about 65,000 trees for the last 27 years. And overall thats about 1,300 different species of trees. That, just to put it into perspective is about twice as many scies as occur in all of north america. Narrator by identifying the species and measuring the diameter of the tree, the team can calculate its biomass. Once this is done to all the trees then the total biomass of the plot can be determined. Dr. Bill laurance its an enormous challenge. It really is one of the great challenges is trying to document what is simply out there. And its tough. I mean, theres no simple, magical answer for that. It takes muddykneed forest biologists to go out there with their various techniques and try to count and capture things. And its a very slow painstaking process. We have teams of field technicians that go out and actually climb the trees. And they collect flowers and leaves that use to help identify the species. We measure the trees. We study how fast they are dyi which new species of trees are coming into our plots. Narrator the researchers found that plots within 100 meters of the forests edge lost up to 36 of their biomass of oldgrowth tree species within the first 10 to 17 years of fragmentation. Plots past 100 meters exhibited no significant changes in biomass over that same time period. Dr. Bill laurance our fragmentation study of the amazon is a longterm study because things take time to change. They dont instantly disappe. Many of the trees would normally live between 400 ars and maybe 1,500 year what perhaps is most stunning is that we are seeing the mortality rates are just going through the ceiling as a consequence of these edge effects and these environmental changes that we are seeing associated with forest fragmentation. So its obvious that the ecology of the rainforest is just being altered in such a profound way by forest fragmentation. Narrator and its not just the trees that are affected, but also the wildlife. Sue laurance studies the impact of fragmention bird specie dr. Sue laurance birds are very interesting to study the effects of fragmentation particularly just the effects of roads because they are highly mobile. They can fly. So a small road of 50 yards or a small clearing really shouldnt inhibit an animal that can fly much greater distances inside the forest. So i caught birds and put little radio receivers on them and moved them across these gaps to see if they can return to what was their home range of their territory. And they know where their home range is because i generally move the male. And the female will be there calling and the males returning the call. So they know where home is. But they are just not choosing to cross the road at all. And thats a real concern when you can see that some of the clearing patterns that we have seen in the amazon where they have just got long roads could still leave 70 of the forest intact but populations could still be divided by a very small clearing. Dr. Bill laurance the roads are in some sense acting as a sort of a pandoras box. Its oftentimes the first step in this cascade of uncontrolled activities. In the amazon, for example we see roads penetrating into the rainforest. The government is putting in many new roads. And then oftentimes you get slashandburn farmers and cattle ranchers and loggers coming in when the roads are there. You get land speculation. You get a very destructive process which oftentimes leads to just largescale, wholesale forest destruction. Narrator by providing concrete examples like how a small road can disrupt the stability t rnft, laurances research is showing just how vulnerable this very fragile, diverse and utterly unique environment really change. Dr. Bill laurance but i think we have to be very vigilan its absolutely essential to understand for the fate of tropical biodiversity what species are gonna be able to persist and which ones are not going to be able to survive in these fragments of forest. Narrator coral reefs have been called the rainforests of the sea. And like the rainforests they are a rich and precious natural resource. But they, too, are being impacted by human action. One small example of this impact took place in april 1986 when a Major Oil Spill on the coast of panama polluted an area of coral reefs, mangrove forests, and grass beds, including a biological reserve being studied by the smithsonian Tropical Research institute. Ecologist Jeremy Jackson is one of a group of scientists working there hired to study the ecological effects of the spill. Dr. Jackson we worked all the way down the coast for Something Like 50, 60 miles to get to places that were less and less affected by the spill. And so we had what were in effect control reefs that were along the coast, and we were monitoring the condition on the coral reefs and the mangroves and everything here and then further and further and further away from where the spill was. Narrator the results of the study were not surprising. The area affected by the spill was severely damaged compared to the unaffected or control, areas. But for jackson, it was the findings made in the control areas after the initial study that would be much more alarming. Dr. Jackson two years later, almost all the corals died in the control areas and they died for reasons that had nothing to do with the oil spill. They died because of disease because of overgrowth by seaweeds. They died because of bleaching. And so that was, i suppose for me the real wakeup call that theres nothing close to natural out there anymore and that it was just fundamentally important and interesting to try and understand all these different dimensions of degradation. So what im really interested in is how have people changed the ocean . What does it mean not just for the Natural World but for us . And what will it provide for us in the future . Narrator to understand the statof the oceans today, jackson uses data from fish surveys conducted worldwide, along with catch records from the fishing industry. But this data does not provide him with all the answers hes looking for. Dr. Jackson if you wanted to know what Manhattan Island was like as a natural ecosystem you wouldnt go to wall street and survey the birds. Wall street has changed in the last 500 years. And in the same kind of way, if you want to know what kind of fish there were in the ocean, you can do a Scientific Survey of fish today, but it wouldnt tell you anything. Some species of fish are extinct, so it would probably be difficult to survey them. Narrator so to put Current Research in the right context, jackson compares it with Historical Records and archeological evidence painting as accurate a picture as possible of the oceans before human disturbance. This picture is called a baseline. Dr. Jackson the baseline is the way it used to be. But every generation of fisheries biologists makes a new baseline when they start their career. And so the fisheries biologists from 30 years ago their baseline was maybe 10 of the fisheries biologists baseline from the generation before. This is an example of the shiftingbaseline syndrome. Its an incredibly important idea. Its the most important idea about understanding the environment and human impact on the environnt. You cannot understand the problem just by looking at the way the world is now. Narrator so jackson looks to the past. And while he researches all of the human impacts on the ocean like pollution and Global Warming his focus has been on the effects of overfishing. He has concluded from various sources that the global population of large fish has declined by 90 since 1950. Dr. Jackson we know things like that from data from the japanese fishing industry. They have a massive fishing fleet, and they kept very good records. And in the beginning of the japanese fishery, they fished mostly close to home. And then they depleted the fisheries in the western pacific. So they moved into the north atlantic and the south atlantic and the Central Pacific and the indian ocean and all of the different fisheries grounds around the world. And in a period of 25 to 30 years, in the entire global ocean the catch was depleted from 10 fish per 100 hooks to one fish per 100 hooks. Thats 90 of all the big fish are gone. Narrator but to jackson this study also falls victim to the shiftingbaseline syndrome. Dr. Jackson their baseline was 1950. And you can imagine how many big fish disappeared before 1950. So, another way we know about the magnitude of the fish weve lost theres this Global Fisheries data that were essential commercial fisheries data and they made maps of how much fish was taken out of the northern atlantic in 1900 and today. And the red color meant that there was lots of fish, and white color meant there were no fish. And in 1900, all along the east coast of the United States and western europe is red. And in 2000, its white. Its just virtually the richest fishing grounds in the world are gone. Narrator besides the obvious concern of extinction to many of these large fish species jackson asks what effect their absence has on the health of the ocean as an ecosystem. Of chief concern are coral reefs. Dr. Ckson the important question is how is the functional diversity of reefs changed whether the species have gone extinct or not . Is it a complex system that works in the kind of way that supports the healthy populations of fish . Is it a Healthy System that protects the coastline from hurricanes and other severe storms . Does it perform all those kinds of things . Theres no doubt that in that kind of functionaldiversity sense, coral reefs have been very, very badly impacted. Narrator like the trees of the forest coral reefs are the foundation for much of the life in the ocean. They provide food and shelter for many plants and smaller organisms which are the bottom link of the food chain. These smaller organisms are the food source for small fish which in turn are the food source for the larger fish that eat them. The simple way to understand it is big fish eat little fish. And the big question is when you remove the things at the top do the next level down just take over . Or is the balance disturbed in some kind of way that its not that simple . Its pretty clear that its not that simple. Overfishing removes the most important and abundant consumers in a natural ecosystem. And so fish, of course eat fish but fish also eat seaweed. If they are not there, the seaweed grows 10 times faster, 100 times faster in the corals. It grows over the corals smothers them, and kills them. Narrator the absence of fish that allows for this overgrowth of seaweed and the destruction of the coral is an example of how removing one part of the food web completely changes an ecosystem from one that is healthy and diverse to one that is only attractive to a limited number of organisms. Its what jackson calls the rise of slime. Dr. Jackson what i call the rise of slime is the introduction of excessive amounts of nutrients that allows the microscopic plants in the water and also the seaweeds on the bottom to grow at extraordinarily rapid rates. If it gets out of control, theres far more microscopic plants and seaweeds than the grazers can possibly eat. The stuff just builds up and builds up. It dies before anything eats it. It falls to the bottom. It rots. The process of rotting consumes all the oxygen. So all the animals that normally would be using that oxygen they die because of this rotting of all this excess vegetation. And all youve got is jellyfish at the surface and all these microbes. And so its an ecosystem which lacks all the kinds of animals we want and has all the kinds of animals we dont want. And so, of course, the big question is will that happen everywhere . Or will it only happen in a few place or will we get smart and figure out how to stop doing that and x it somehow . Narrator some of jacksons research is showing that avoiding the rise of slime is not so complicated. In the summer of 2006, jackson and researchers from the Scripps Institute of oceanography released results of a study that evaluated the effectiveness of Recovery Efforts on reef systems. The Research Team sampled levels of biomass for fish, corals, and algae at 34 coral reef sites in the northwestern caribbean and off the florida keys. The sites ranged from fully protected notake marine reserves to reefs that had been historically overfished. Sites designated as marine reserves larger than 100 square kilometers with no fishing allowed for more than 10 years have the greatest levels in total fish biomass, including not just top predators, but also herbivorous fish who are important in the food web for reducing algae abundance. Dr. Jackson in those places surprise, surprise you dont kill the fish, the fish come back. And theres lots of fish and lots of big fish. And whats really important is even though its very complicated and we dont understand all the details, in those places where theres lots of fish theres been a huge reduction in the seaweed. Now, the corals havent come back yet because the corals grow slower. So its gonna take a long time for corals to come back. And, of course, there are other problems that corals have. But at least half of that story the elimination of the large amounts of seaweed has now been shown effectively, experimentally, through the mechanism of these protected areas in seeing the reduction in the seaweed. So, is it too late . I dont think its too late. But will we be able to go to the beach . Will we be able to eat fish . What will it be like . Thats really hard. And theres a lot of science there. We know it will be better you know if we stop killing fish, there will be more fish. If we stop dumping too much garbage in the ocean, the ocean will be cleaner. And it will be better. But what exactly it will be like and how well we can manage it to protect the natural biodiversity and to still have fish to eat and still have clean beaches to go thats a harder, you know, and thats what a lot of us are trying to understand. Funding for this program is provided by annenberg media. For information about this and other annenberg media programs, call. And visit us at. Funding for this program was provided by. In honduras, archaeologists piece together fragments of an ancient message. What secrets could these symbols reveal