 Hi, everyone. Final full lecture today in ecology, which is just great. It means you're advancing well through the semester. It means I can start to really focus on research. It's exciting. But I've enjoyed this lecture series a lot. We'll finish it up on Monday morning. On Monday, I will conclude and give a very quick overview of the whole series focusing on points of potential problems, points where I know there's been some confusion over the semester. And then we'll go into question and answer. Best if you can send me questions in advance so that I can have some material prepared. But if you want to just fire questions at that time, assuming there is enough time, you're most welcome. But if you can ask questions on email, that's great. And then if a few of you are focusing on a similar topic, then I'll know that that's a topic of confusion, although I do know of a few of those already. That's enough for now. Let's just get into today's lecture. Office hours are as usual after lectures and by appointment if you need to set one up. So let's get into our discussion of ecology today. This is really a focus on the role of ecology in environmental problems. That's what I've chosen to focus on here. Ecology is an extremely dynamic science. Much of the present and near future of ecology will be in terms of its integration with other disciplines, its integration with geology and with anthropology and sociology. As it always has been, ecology is an integrative field and many of the solutions to our current problems, both in science and in the world at large, concern the need, you know, require that type of integration across disciplines. Here I'm focused on environmental problems primarily. You know how you watch a nature video on TV and it's an hour long video and you see all this cool footage of the rainforests or, you know, whales feeding in the seas and then at the end it's the humans butchering the whales or cutting down the rainforest. You always get that at the very end of the program. That's kind of what's happening here. I'm giving you the problems here on earth with the systems we've been looking at here at the finish. So you've seen the topics here and I'll just get into them. Yeah, we could spend a lot of time on environmental problems and we could choose any number of them to focus on. I'm just going to choose a few of my favorite environmental calamities to talk about today. We just would need a whole year to talk about all of them in any detail. So what I'm going to try to focus on are a few of the most important problems that we face but by no means will we have full coverage, broad coverage. And I really hope you will continue to explore these issues and their solutions and other courses here and in the future. There's obviously very important roles that we as individuals and as communities can play toward the solution of environmental problems. Ecologists have a particularly unique role to play in the solutions to these problems. To create a bridge to last time, remember we were talking about measurements of carbon dioxide from gas bubbles trapped in Antarctic ice. And a record of carbon dioxide in these gas bubbles as representing carbon dioxide in the atmosphere over these hundreds of thousands of years showing that carbon dioxide has cycled in parts per million relative to other gases in these bubbles, reflecting a cyclical change in temperature on a global scale. It's assumed from these bubbles as they represent the atmosphere trapped in that region can provide some window on global atmospheric conditions and a reflection on temperature. Let's look into that a little more and let's extend it to today. We have spectacular data from Mauna Loa in Hawaii, a high-elevation observatory where since the early 60s, carbon dioxide has been monitored in the atmosphere at these relatively high elevations. And these data are some of those that have proven so valuable in the discussions of global warming and global climate change. These data have been known since this time and have been scientifically well discussed since at least the 70s. The effect of carbon dioxide as a trapping, as a gas that can trap radiation and warm an environment, that's been known for over 100 years. And speculation on the role of carbon dioxide and other gases as they enter the upper atmosphere, as mechanisms to trap radiation as it bounces back from the Earth into space and to hold it into our atmosphere here close to Earth, that phenomenon has been known for 100 years and been discussed actively. This is not some new-fangled science. I was presented... I first heard about this information in the early 90s in a talk that was very compelling and started to talk about it with people I knew. It seemed very compelling. The data seemed real. The scientists seemed honest. And here we are today with quite rapid debates about the significance of these data. Let me talk to you a little bit more about what we know. We know that carbon dioxide, as measured in this observatory, these are actual data of carbon dioxide in parts per million in the atmosphere measured at Mauna Loa, have been increasing in the cyclical way across these decades to the present. And you can think about that in relation to our previous data. In parts per million, we're at about 320 parts per million carbon dioxide in the atmosphere in 1960, close to 400 parts per million today. If we look back at that previous slide, we can see that that's exceeding anything apparent over the last several hundred thousand years based on the ice core data. Looking at just the last five years, you're seeing the same trend of increase in carbon dioxide. This is the trend smoothed over the seasons. Why does carbon dioxide fluctuate like this? Across a year, these are monthly intervals. Seasons, what about the seasons? What about the seasons in the world affect carbon dioxide in the atmosphere above Hawaii? Plants, what about plants? With the seasons in the winter, plants are absorbing less carbon dioxide as they become quiescent and don't photosynthesize as much. They're eating less carbon dioxide, but they're still respiring, but they're still releasing some carbon dioxide. You have much less uptake and a continued production by your primary producers leading to these cycles. In summer, much more uptake by the primary producers. You get these cycles across seasons with a steadily increasing trend. There's nothing to argue with this. These are the facts, ma'am. A link between this and anything in terms of warming or climate change is also irrefutable. A link between carbon dioxide and the trapping of radiation and the warming of an environment. That's your greenhouse effect. That's physical irrefutable evidence. Whether this is having an effect in the world, that's where the debate occurs. Measurable increases in temperature, though, have been documented. You see every couple of years, yes, we've just had the hottest year on record. It seems that we keep exceeding ourselves in terms of global average temperatures. Is this correlation a result of causation? Scientists don't disagree very much on this in spite of what you might hear in the popular press. Most agree that there is a real causal effect here and that the production of CO2 in the atmosphere is largely a result of fossil fuel burning in production. This is just the warming aspect of the phenomenon of global climate change. In a way, scientists are to blame for the confusion, the popular confusion surrounding this, and having just focused on warming, the warming trends related to greenhouse gases. And CO2 is just one of them. Methane is another major one, carbon monoxide and others. We have called it global warming, but it entails much else with regard to changes in climate, changes in precipitation, areas becoming more dry or more wet over time, with fog here in California, how these changes might influence fog regimes. Temperature is just one aspect of it. And so when we call it global warming and we have a really cold winter with a lot of snow, like last year, everyone can say, aha, it must not be happening because it's so snowy outside. There's three feet of snow. Global warming, phew, impossible, right? That's so scientists probably could have done better in the years in clarifying what was meant by quote-unquote global warming or sticking to global climate change in the whole discussion here. This is something you don't hear that much about anymore. You're used to hear more about it. This is the phenomenon from 1979 here to today. The formation of a very thin ozone layer, particularly over the southern pole, meaning of the ozone or the whole, the ozone hole. This, you hear less and less about it perhaps because changes, political changes, in terms of the use of chemicals, particularly chlorofluorocarbons, have helped to mitigate this problem. And yet the problem remains very real. The hole over the Antarctic in the ozone layer reached its maximum extent just in 2006 and today, as represented by the bluer and purpler areas of this, measured in dobson units, which I'm not exactly sure how you compute, how you measure this in dobson units, but the bluer purpler regions represent a thinner layer of ozone. This is very much real today. And you can go online and look at today's hole, the hole as it exists today, and you can do that on a daily basis if you want. It looks much like this. And it changes seasonally as well. But changes in relation to our use of, particularly those CFCs, remember those are the chlorofluorocarbons, are the things that Al Gore could actually pronounce and got him into so much trouble for being able to pronounce it. He seemed like such a geek. He had a lot of trouble with the use of this problem early on, and fortunately, there was pretty good political movement on this and restrictions on the use of those CFCs have helped to mitigate this problem. But here, we can see this in terms of the percent change in ozone over time, the fact that we've have seen these decreases, in the late 70s is where it really took off through to the early 90s, and this is where I started to hear about it, and you really used to hear a lot about it here. And then look, it's maybe stabilized a bit, but it remains a real problem. What is the problem here with a thinning of the ozone layer? And just here to show you that at zero degrees latitude at the equator, percent ozone change is much less than it is at the poles. And thus, maybe we hear less about it here than they hear about it in Australia or in Southern Africa or places like that, where it's a more significant influence, South America, the tip of South America, where it's a more significant influence on people and organisms than it is for us here in California. Well, what's happening, this ozone layer in the stratosphere, O3 ozone, in the stratosphere, above 15 kilometers over Earth, helps to protect the Earth from harmful UVB radiation, ultraviolet B radiation. Ultraviolet A radiation can penetrate the ozone layer fairly easily, but ozone UVB is reflected back into space. Very harmful types of radiation that can cause cellular malfunction, can cause mutation, genetic mutation and can be harmful both to humans and all organisms and can be responsible for skin cancers and interruptions of growth cycles in plants and all other creatures. Ozone in the very lower atmosphere we hear of sometimes because of its role in pollution, in smog, ozone down here is far less desirable than ozone up here, so you should be aware of that. You can look at the details of how this process works in the book, just a figure from your book, how CFCs and chlorine break up the O3 ozone molecule into a free oxygen molecule and a bound oxygen chlorine monoxide or something like this, that then with radiation, with sunlight, will break again to free the chlorine molecule and cause this cycle to proceed further. So your chlorine breaks up the oxygen, forms a new molecule that then breaks up releasing that chlorine to be allowed to go break up another molecule of ozone and that degradation continues in the presence of sunlight. So by limiting the amount of chlorine heading into the upper atmosphere, we mitigate this problem. Closer to home, problems with refuse, you've all encountered this, the reality of the problems of consumer waste and what to do with it here on Earth. Obvious problems stemming from a landfill environment like this are the leaching of chemicals into neighboring waterways, the release of gases from such landfills that can play a role if you drop your refrigerator into one of these landfills. The gases in your refrigerator can escape and get into the atmosphere and potentially cause, for example, problems in the ozone layer. But more locally, problems with runoff waterways affects organisms and communities, including human communities, as it pollutes drinking water. But did you know that in the oceans, for example in the Pacific, these gyres of currents collect trash into these massive zones of debris where the trash coagulates and fishing nets and everything from slippers and trash cans all manner of things collect into these giant debris zones in the Pacific and they've been identified in the Atlantic Ocean as well. You know, twice the size of Texas here, they say. This fairly concentrated zone of debris. Now, it's not like it's completely dead. Organisms are living on these plastic bottles and you have some mollusks attached and crabs. Who knows, maybe evolution is occurring quite rapidly there, these new ecosystems. Probably so. But this is also a major hazard to existing forms of marine life. Some of the dramatic examples come from birds such as albatrosses where the parents are collecting this trash feeding on it, considering it something to eat and bringing it back to their chicks and feeding the chicks. And you get a chick with a belly full of plastic and debris and if the parents don't die right away, well, the chicks will starve because they're hardly getting any nutrition from this. So organisms are eating this stuff. Turtles are getting caught up in this stuff and this is something, you know, as individuals we could be more careful about. About the way we do or do not recycle these materials as opposed to having them end up on the beaches and in the water. Or perhaps choosing alternative types of materials with which to construct our bottles and cups rather than long lasting plastics in the first place. Things like this. But did you know that we have problems with refuse and debris in space? These are representations of, these are actual objects of debris being monitored by NASA in space. Mostly from satellites and, you know, rockets that have, satellites that have been abandoned and, and, or rockets that have exploded and cast debris about. These things are orbiting Earth. They're not, this is not to scale. Objects are not this large. Some of them are quite tiny. But something this tiny moving as fast as these objects are moving can be incredibly destructive to functional satellites and so forth that are in the, in orbit here. So we have problems at several levels with simple physical debris circulating in these areas. In these ecosystems. Not sure you can call these ecosystems unless you have living organisms present. Just another representation of actual debris loads on Earth. Yeah, but that's not, you know, heading into space. We're leaving Earth and the problems we have with organisms here. And that's one of the frustrations that ecologists sometimes encounter in science. Incredible, incredible funding is put into space exploration and the development of space programs. Ecologists would not want to say we shouldn't do that. But they should say, hey, why not also put equivalent sums into our problems here. And that, that can be a source of frustration when billions and billions are spent off Earth. Whereas so little is put in so very often to problems on Earth. What is going on there? Why do we do that? To some it can seem like a sort of escapism from our real world problems. Here's a definition of conservation biology. It's a bit narrow, but, but we can think of conservation biology as a type of applied ecology. Primarily concerned with population declines and their causes. So an applied ecology concerned with changes in species numbers, changes in numbers of individuals in species populations. The study of that and the study of the explanations for such declines. And this is happening in so many species. We're seeing declines in numbers. What is a hazard when population numbers decline in a species? Why is that a concern? Anyone? What's wrong with a small population? Extinction risks. You'll get a lot more of this in the evolution section, but there's a concept of an effective population size below which a population is vulnerable to chance events and to other phenomena of extinction. And so if populations dip in numbers below a certain size, they face the reality of extinction. So what? There are a lot of species on Earth. We don't know how many, but there are millions. Well, not all species are created equal. Some are dramatically more important to us as humans than others. Are all species worth fighting for? These get into moral and ethical arguments. I mean, the parasite, the nasal fungal parasite that infects human beings in the tropics, is that worth fighting for if it were at risk of extinction? Would you want a battle for that? Maybe not to the degree you would want to battle for if we have a pecking order here on Earth in terms of who we invest most resources in activity in trying to protect and save. But we need to be careful. We tend to go after the charismatic big organisms that we like to look at and that seem cool or cute. So these charismatic creatures really devote our energy and resources to. We might want to question some of that distribution of activity and energy. I won't name names, but you can guess maybe of some of these creatures. And then what I'll want to suggest here is that maybe we also need to and ecologists certainly are doing this and have been arguing for this, we need to pull our perspective a bit towards the individual species and look at whole ecosystems and look at the preservation of habitats equally. But let's just take a couple of examples from populations in stark decline at the moment that if you don't know about them maybe a good idea to know about hopefully these things will turn around and this will just become an anomaly of the last few years. There has been a stunning collapse in honey bees and it's called colony collapse disorder. People have been keeping bees for millennia. Humans have been had this mutualism or commensalism or something with bees. If you think the bees are getting a lot out of this then this would be a mutualism where we certainly are benefiting from the products of honey. The bees are benefiting, they get a place to live and they get tended to but who else is benefiting from this system of huge number of plants by virtue of the pollination of those plants by these bees and via the plants huge numbers of other organisms and species in the communities where these things are living. This is a complex network of connections where the bees play a critical role and today these honey bees are extremely important you probably can't read it out there I'll give it to you on the slide extremely important in the pollination of human crops so this is just in the percent percent of these crops pollinated by honey bees for example almonds looks like if you believe the data here from this New York Times article almonds are exclusively pollinated by honey bees if you didn't have the honey bees you'd have a real problem in propagating almonds or apples primarily pollinated by honey bees peaches, blueberries and so what we've been seeing are the collapse of colonies colonies collapse naturally they'll just go through these die off periods in 2006 or so it's been a striking die off where the beekeeper will go out and just either the worker bees are gone they've just disappeared or there's just dead bees all around the hive and quite simply it's not known what's happening here mites are probably part of this fungal pathogens are probably part of this but this is led into the context of global climate changes and the alteration of local systems some people think that alteration of local systems has caused nutritional problems for bees what you have as in so many other cases is a combination of stressors and non-linear effects between stressors that can lead to disease in the population and these multifactorial stressors can be hard to tease apart and it can be hard to single out any one specific smoking gun problem it can be hard to find that smoking gun as to which of these is the cause we tend to seek the cause what's the cause of this well in ecology it's often multifactorial you often have a combination of causes that have antagonistic effects you may have heard of a synergy where one effect combined with another effect produces a combined effect disproportionate disproportionately large larger than the sum of the two effects individually that's what you get in ecology you get these kinds of circumstances and ecologists are actively studying this it's an agricultural crisis it's a boon to people who have colonies and drive around in their trucks and park next to farms and the farmers pay them so that the bees can sit there for a while and help to pollinate the crops and then they drive on to the next county and park again it's a booming business right now if you want to get into that hopefully this will just turn around I really hope in ten years this will be a historical blip yeah question in the back importing bees to try to replace the honey bees colonies that are collapsing I haven't heard much about that and let's talk about invasive species a bit because that may be something that we should focus on but the intrinsic risks doing something like that are absolutely fabulous and ecologists are very careful about that for good reasons I'll give you a couple examples of why we need to be really careful about those kinds of introductions sometimes they present great solutions though just quickly bats again this was first noted in just 2006 white nose syndrome you find these bats it's a fungus that's attacking them primarily around the muzzle there also on the wings hibernating bats it's a fungus that requires very cold temperatures to grow so it's just bats that are hibernating in the caves in this region first noted in Pennsylvania or New York somewhere here but each year more and more it's similar to the bees these kind of collapse of the colonies where you find a bunch of dead bats around the cave the fungus seems to rouse them during their hibernation from their torpor so they wake up and as a result starve because they wake up and there's nothing to eat when they should be hibernating starve and die hopefully this will just remain limited to bats in colder areas but it's spreading and they're closing caves it's a fungus so the spores of the fungus can be easily passed along on human clothing and caves are widely visited by humans so visitors to caves here if they visit another cave in the Rocky Mountains they could transport this kind of fungus so many caves are being closed to visitation another real crisis bats are great pollinators too but bats are great insect consumers bats are voracious mosquito consumers for example they are tremendously important just partly out of their sheer numbers and the rapidity of their activity in community structure we can't afford to lose our bats so ecologists are out there and trying to assess the problem the fungus is obvious you walk in and you see their little white noses but is that the cause is there not a complexity of causes a complex of causes that are giving rise to this problem it's hard to tease apart so if we have to just choose two of our favorite environmental problems to focus on as most important they might be habitat alteration and invasive species and so those two I'm just going to review here habitat alteration is what it sounds like it's just the changing of natural habitats for some human use often this is in order to clear land for agriculture or development of some kind and obviously when you take a forest and you knock it down you're radically changing the physical conditions and the physical environment for the living biota you're not only removing species but you're altering the physical environments for the existing and remaining species you're creating edges to the systems that you leave intact you might clear this land and say okay I'm going to leave this patch and this patch and it's less than existed before organisms will have less space to live in but at least they have these patches we'll look at the effects of creating such edges in a minute here but just examples maybe close to home for some of you there and here's a very common phenomenon of a region settled in development developed for human activity over the years you end up carving up the original system into patches that then get winnowed to smaller and smaller patches less and less space for organisms to exist in but notice that the effect on a percentage basis that this has in terms of the role of the edge in the functioning of those patches these are artificially created edges that's what I'm describing here anthropogenically created edges edges in natural systems are often very fertile boundary zones we introduced the concept of an eco-tone right some of you probably maybe a lot of you didn't understand it and I'll address it again on Monday but an eco-tone is a boundary system between communities that's often very rich because it shares members from the two neighboring communities and then has members that are unique to itself unique to that eco-tone and it's often very fertile and diverse so that's an edge that's an edge zone in a natural circumstance but an edge created artificially is somewhat different here's an example of some human beings moving in and cutting out of forest years later the edge isn't holding up in this kind of structure where you have these species of tall trees living at those edges with your sub canopy and a ground layer of vegetation instead you might see this kind of pattern, an effect of the edge in this way, think about what happens to the physical environment at the edge if you cut say the forest that existed here this region which had been in the shadows with cooler temperatures less exposure to wind is now exposed to a lot of sun a lot of wind and warmer temperatures these plants are not acclimated to that type of condition they won't be able to survive it the community will change and it will be pushed back in a sense those plants will be lost others might survive for some time but you'll have reorganization of the community in this area the community reorganization is going to ripple through such a system so patches with a lot of edge are going to be nibbled at from the edges in terms of ecosystem dynamics and this needs to be considered when thinking about areas to conserve and preserve buffer zones are now a fairly standard part of preserve construction creating a zone of maybe limited use around an area of more strict protection because that buffer zone can help to buffer the interior system against the insults from the exterior system sort of creating a more gradual edge effect if you want and here's an example with Grizzlies from your book those patches of habitat what if we're talking about squirrels in those patches of habitat it might be hard for the squirrels to get across those open agricultural fields across the roads in order to find other squirrels with which to reproduce and you can get these very small populations in those patches vulnerable to local extinction or vulnerable to inbreeding problems such that the cross-pollination if you will of squirrels between patches is critically important and thus the necessity of creating corridors which organisms can pass when moving between patches these habitats are inevitably going to be patchy and fragmented and corridors can help a lot for some organisms to create connections between patches to allow organisms to cross and commingle and you see this sometimes on highways bridges constructed particularly in areas where you have an endangered species or a charismatic species that's of interest bridges specifically constructed as passageways for say elk or something like that this probably could have gone earlier I just wanted to focus on the major problem of alteration of the nitrogen cycle and the runoff of nitrates from agricultural communities the whole Mississippi drainage basin up into the interior of America think of all the farms along the rivers that eventually lead into the Mississippi and other rivers that eventually dump into the Gulf of Mexico all the runoff from those systems all the fertilizers that are used on these agricultural lands that make their way into the waterways down the waterways and ultimately into the Gulf what's one thing caused by those inputs of course elements that are used as fertilizers are used as fertilizers because they're often limiting to organisms to plants or crops well they're often limiting to other organisms in waterways and when they get into those waterways they cause explosive blooms and so in the Gulf of Mexico a very real phenomenon for a very long time has been the formation of these dead zones of activity where runoff has created blooms that have deprived these systems of oxygen poor Gulf of Mexico add insult to injury this is a this has really been a dumping ground for Americans for a long time it's been completely mistreated and it's so heavily taxed to begin with it's an incredibly rich region and fertile region for the production and in spite of all this and now you have this and we need to do more to just lessen the impact before we get complete system collapse and you know that's the stuff I'm presenting here is not technically difficult I'm hoping if this is news to some of you that it'll get you to think about some of these things differently and maybe get us to think about our own individual actions a little bit and what we can do at a community level for some of these problems they're way too big for any individual here to solve but we can all do small things invasive species another of my favorites this is the brown tree snake that's moving around the South Pacific has been for a while it's a great invasive it gets to islands settles in it's a little constrictor I believe it's a predator of small vertebrates primarily and just starts to devour the local birds lives primarily in trees just voracious just eats everything that it can handle and wipes out the vulnerable many of these small tropical islands extremely stubborn and hard to manage and moving along on ships easily moves from island hops and so people take strenuous measures to search ships when they come to port to see if any of these things might be hiding out but it's extremely hard to handle an example of a great invasive species one where that encounters island faunas and these insular faunas are often particularly vulnerable to such invasions because they haven't evolved with similar predators maybe one if any of you are from the southeast U.S. kudzu it's a Japanese plant that made it into the southeastern U.S. you drive along the highways or in some local communities in the southeast and you just see these banks and banks of this viney looking plant and you have these trees you have your trees your forests but all you see is kudzu because it's just festooned over all the trees just blanketing them an invasive climbing plant that you can imagine the effect if you're a tree and you're covered by this it's going to be capturing all the light and the photosynthetic doing all the photosynthesizing smothering the tree underneath and you can study in Africa where they live natively giant African snails these are the biggest snails on earth there are a bunch of species in Africa and they're fabulous in Africa keep them there thanks very much but the fact is they're great food for people if you know how to cook them properly in blind taste tests they perform just as well as your finest escargot and they're huge bigger than your hand and pack a lot of meat and so during the world wars in particular they were exported around the world as a possible good food item for people anyway they did all too well in tropical islands around the world great consumers of crops voracious plant eaters and have been extremely hard to eradicate from tropical island environments across Brazil quite frantically at the moment they have been introduced and released in Florida and Arizona places where they actually were eradicated through very strenuous efforts as much as I would like to keep they make great pets they're just lovely and I really want a couple as pets but I would have to get scientific permits to be able to keep them you're not allowed to bring them into this country but as an attempt to control them and this is one of these examples of a possible solution gone awry these carnivorous snails are introduced into places to try to manage these invasive African snails so you introduce an exotic species to try to manage a a problem species well these things although they will eat Akatina you introduce your predator and it wreaks havoc on the native mollusks and hardly limits the target population just a couple of these warning examples the mongoose is a famous example of this this small Indian mongoose herpestes oropunctatus or gevanicus first introduced in Jamaica to control rats in cane plantations it ate some rats but the rats tend to come out at night and the mongooses tend to come out in the daylight hours so they didn't even see each other all that much but the mongoose was very happy to eat the local snakes and birds and insects and this is another one that's on many tropical islands and extremely hard to eradicate so we need to focus on ecosystems whole habitats and not just particular species these are the places where these organisms live after all both on land and in marine context what do you know George Bush preserves a marine area around Hawaii and the Pacific that's one of the biggest in the world on his way out nice work W great effort anybody can do this yeah sorry about that I'll try to leave it on a positive note here restoration ecology here's an example from an area in New Jersey before ecologists moved in and introduced organisms that are known to grow in such a wet environment in such an area this is a former mining area after 10 years you can reconstruct something like this yeah it just makes you feel better right or if you want a great example is just down at the marina in Berkeley you can go see burrowing owls there this is a former landfill great park right down University Avenue there have a good weekend everybody