 in a remarkably diverse world. 1.4 million organisms have been identified in biologists estimate that 10 to 100 million organisms may in fact inhabit this earth. But the number of organisms isn't the same from one community to the next. For example, if we look at the wetland behind me, there's another different list of species in that area as opposed to the riparian forest behind it or the coniferous forest on the hill or even within different age classes of coniferous forest, you get different types of organisms and different numbers of organisms. Agricultural land or natural grasslands, they have a different group of species as well. I'm Dan Edge. I'm with the Department of Fisheries and Wildlife at Oregon State University and we're here at Finley National Wildlife Refuge in the Willamette Valley of Western Oregon. During this video, we will examine some of the questions such as what causes the distribution of organisms on the landscape? Why are there more organisms in some areas than in others? What are some of the primary and secondary factors which affect the distribution of organisms? These concepts are extremely important when it comes to conservation planning. Whether you're talking about planning on a farm scale, at a watershed scale, or even at a regional scale, it's important to keep in mind the distribution of organisms. To begin our discussion of biotic communities, we need to talk about biodiversity for a few moments and it's important from the standpoint of understanding how it is influenced by landscape scale processes. First, I'm gonna talk about some definitions, use some terms, define some terms that I'm gonna use throughout the presentation. The first term that I'd like to talk about is biodiversity. Biodiversity is the variety of living organisms considered at all levels, from genetic through species to higher taxonomic levels to the ecosystem level and even the landscape level. Thus, there is a hierarchy of biological diversity that should be considered in conservation planning. In 1990, Reid Noss in an article on conservation biology proposed a hierarchical approach to monitoring and managing biodiversity and he proposed that there were four basic levels that we need to consider. First, there is the genetic level, second, there's the species and population level, third, there's communities and ecosystems level and finally, there is the level of landscapes. All four levels we need to think about conserving and managing biological diversity and private landowners are an important component of these conservation practices. So let's look at each of these levels in term, define them and talk about some examples as we go along. First is genetic diversity or the variability in genetic makeup among individuals of a species or breeding population of a species. Genetic diversity is the ultimate source of biodiversity at all levels. Genetic diversity is the material upon which the agents of evolution act. The next level of biodiversity is the species and population level. So let's talk about species. A species is a group of actually or potentially interbreeding populations that are reproductively isolated from all other kinds of organisms. Classically, species were based upon readily identifiable morphological characteristics, such as flower parts for plants or perhaps feathers or teeth for some of our vertebrates. But our recent advances in molecular technique allow us to identify species very precisely using genetic criteria. Conservationists are often concerned with protecting individual species that have declined because of human or natural causes. The species level is the unit of biological diversity that the endangered species act typically targets. Protection of a species listed as endangered or threatened under the ESA is often directed at the population level. A population is a subgroup of interbreeding individuals within a species. It's important to talk about populations within a species because we need to focus on the resilience and adaptations or adaptability of populations within a species as we talk about why it's important to conserve populations. This level of biological diversity is important because if populations remain isolated over long time periods, then they have the potential to evolve into separate species. And once again, trying to maintain or enhance, if you will, this variation, this resilience and adaptation that these individual populations have is important from the standpoint of conserving biological diversity. The Endangered Species Act recognizes the importance of this variation within a species. And it is the reason that protection may be extended to a population rather than the species itself. Fish migrations are the classic example of this. Each migrating population or stock or run of a species such as coho salmon are relatively unique. Genetically, because of the majority of individuals within a specific stock return to the same stream from which they were reared. Each of these runs is adapted to the unique physical characteristics of the river stream in which they were hatched and to which they will return to spawn. This close adaptive affiliation to natal streams is genetically based and offers a resilience to the species as a whole in times of ecological or human disturbance. The species has a better chance to persist. Different populations of coho adapted to different river and stream systems and different conditions spread out the risk of extinction from catastrophic events. These unique runs or population segments are known as evolutionary significant units. An evolutionary significant unit is a group of organisms that share evolutionary lineage and contain the potential for a unique evolutionary future. Now the third level of biodiversity that I wanna talk about is the community and ecosystem level. A community is defined as an assemblage of species of populations which occur together in space and time. Communities occur everywhere on the landscape. A community is an interacting group of plant and animal species in a particular area. For example, this outfield recently harvested could be considered a community. Communities in many senses are scale dependent. So for example, the ruminant stomach of a cow might be considered a community. It has a group of microorganisms in it that help that stomach function properly. A rotten log and a forest might be considered a community. In fact, you might consider this dirt clod community. In fact, this is an extremely diverse community. It may have up to 10,000 organisms, microorganisms and nematodes in it. Many of which may never have been identified. Associated with the community level of biodiversity is the ecosystem level. An ecosystem is the biological community together with its physical environment. Thus the ecosystem contains both the biological and physical elements of the environment. We might talk about stream ecosystems for an example which would contain both the community of organisms and the water, soils, rocks and other components which make up the physical part of the environment. The final level of biological diversity is the landscape level, which represents a physical grouping of ecosystems and communities associated with this specified land area. Watersheds are a good example of the landscape level of biological diversity. Watersheds typically contain multiple communities or several ecosystems. Private landowners and their actions on the landscape directly and indirectly affect all levels of biological diversity. Most of our discussion in this video will target the upper levels of biological diversity, that is the community or ecosystem level and above, the level at which most landowners operate. And we will use a common currency to gauge the condition of communities and landscapes. This common currency is species richness. So let's turn now to a discussion of how many species there are on the planet and how much biodiversity there actually is. So how many different organisms are there? How many different species are there in the world? Estimates of a number of species worldwide are highly variable. Approximately 1.5 million living species have been identified. And estimates of the number of living species range from 10 million to as high as 50 million. And sometimes some estimates go as high as 100 million. These estimates are based on the rate at which new species are identified. And so the rate at which new species come in to our level of knowledge determines what the ultimate total number is. Thus, most species of organisms, as you can see, if only 1.5 million have been identified, you can see that most are unknown. And unfortunately, most are likely to go extinct before we ever even name them, much less understand their importance from an ecological standpoint. So let's look at some examples of taxonomic groups in species. Here in this table, you can see we've got taxon, which is the different groups of organisms, the number of species which have been described, the estimated number worldwide, and then a description of what percentage of the total number have already been described. So for example, with fungi, we see that there are approximately 80,000 species have been described. It's estimated that there are 1.5 million species of fungi on the earth. With 5.3% having been described. Vascular plants, we know quite a bit more about. Approximately a quarter of a million of these have been described. It's estimated that there are half a million and 50% have been described. If we go to more obscure organisms, such as roundworms, we see that 20,000 of these have been described, and it's estimated that there are at least one million roundworms on the globe. Thus only 2% of them have been identified. Arthropods is a very large group, and it has approximately one and a quarter million have been identified. It's estimated that there are at least 20 million arthropods on the earth, and thus only 5% of those. And then finally, vertebrates, a group that we know quite a bit more about. There have been 40,000 of these identified. It's estimated that there are 50,000, so a good 80% of all the vertebrate species that we know quite a bit more about have been identified. Many of these species will become extinct before they are described. Estimates of extinction rates are just as variable as estimates of the total number of species, but by all accounts, the rate of extinction has accelerated dramatically since the late 1800s. Estimates of loss in the future are staggering. It's estimated, for example, that 20% of all species will go extinct in the next 20 years, and perhaps as high as 50% of all species may go extinct in the next 50 years. Most of the species occur in tropical rainforest that make up only 7% of the earth's surface. There are a number of reasons that species may decline, and it's important to very briefly look at those. There are four basic reasons in which species have been listed on the Threatening Endangered Species list. The primary reason is habitat loss and fragmentation. These are changes in the environment which are primarily caused by human activities. The second most common reason is the introduction of exotic organisms. Through our activities on the landscape, we have on purpose and accidentally introduced large numbers of both plants and animals around the globe, and many of these have turned out to be very serious competitors and very serious predators on many of the natural species. The third most common reason is over-exploitation. This is a reason which was more common in the early 1900s as a reason for species resulting in species being listed on the Endangered Species Act. Species which have high economic value, perhaps for their fur or for their meat, are often over-exploited, especially in areas where they are held in a common resource. Fisheries, for example, are a problem where all different countries of the globe may be trying to harvest fish at the same time and this common resource may become over-exploited. Finally, it's important to remember that extinction does happen naturally. There are natural causes of extinction. You may have very isolated, small populations of species which can be completely wiped out by environmental catastrophes such as an earthquake or a flood or a volcano. You may have very small populations that may get wiped out because of a disease or something. So it's important to remember that there are natural causes to extinction. But the major reason that most species are listed on the Endangered Species Act list is because of human-caused activities. So what can land managers do to help stop the decline in the number of species? We need to start thinking about how species are spread out globally and we need to have a better understanding of the ecological processes that occur on our landscapes. If we have a better understanding, then we can be better stewards of the habitats we manage on our lands and thus help conserve species richness and biological diversity. Welcome to the Fish Museum in the Department of Fisheries and Wildlife at Oregon State University. This museum is like thousands of museums around the world. The scientists in this museum do research trying to determine if one species of fish differs from another. And so they're doing some basic taxonomy work looking at different types of fish. They are also doing work looking at natural history traits of fish. It seemed like a good place to bring you to talk about the common currency that scientists use when they're talking about species in different areas or in different habitats and that's the concept of species richness. And simply to find that's the number of species in a particular site. So we could talk about, for example, the species richness in this museum, which frankly is not a very interesting topic, but more commonly we might talk about the species richness in the tropical rainforest or the species richness in a wetland. There are a couple of specimens that I wanna show you or one in particular that seems to bring together a number of ideas that we wanna show in this video. I know it's around here somewhere. Okay, here it is, here it is. This, this is the Miller Lake Lamprey, a neat, neat little parasitic fish that feeds on trout primarily. So it's a fish that attaches itself to, with its mouth parts to a fish and feeds off of it and eventually the host fish will die in most cases. This little critter was discovered in Miller Lake by Dr. Carl Bond in our department back in the early 50s. And at that time, Oregon Department of Fish and Wildlife was trying to establish trout fisheries around the state and lakes that didn't have them. And they had tried several times to establish a fisheries in Miller Lake and really couldn't determine why. And apparently these guys are so voracious that any fish released into the lake really didn't last very long. So Oregon Department of Fish and Wildlife decided that in order to establish this trout fisheries, what they would have to do is cleanse the lake, so to speak. And so they wrote known, used a chemical called rote known, which kills all fish in a lake. And then they stocked the lake with trout. Never since that time, Miller Lake has had a fabulous trout fishery. But this species and this particular population went extinct and it was thought to be extinct for almost 50 years when it was rediscovered by some graduate students in the early 90s that were doing a survey of some streams near the Miller Lake area. And so all of a sudden here's this extinct species is rediscovered and it's no longer an extinct species. But there's a couple of important lessons here. One, the practice that ODF and W went through, Oregon Department of Fish and Wildlife went through to cleanse the lake is not uncommon. And it was not uncommon back in the 50s. Not something that they would typically do now. But it does show you that what is thought to be the best management practices many years ago would no longer be considered acceptable. It also shows that some species are extremely difficult to find. Little fish like this, which are small and secretive, they stay under the rocks, may go undetected for years and years. And so the idea of species richness can be a little clouded because of the difficulty of detecting some species. And this is a vertebrate. You can imagine the difficulty you might have finding some nematodes say in soil or some bacteria and water or something like that. So the idea of species richness is extremely complicated by the difficulty in detecting some species. So what are some of the factors that might explain patterns of species richness that we see? Geographic factors explain many of the patterns we see in biological diversity. Species richness is broadly related to geographic factors such as altitude, latitude, and for aquatic environments, depth. Latitude is probably the most widely recognized pattern in species diversity. Regardless of the environment or species group, the number of species decreases as we move from the tropics north or south towards the poles. This can be seen in a wide variety of organisms covering terrestrial, marine, or freshwater habitats. For example, there are typically 30 to 60 species of insects and freshwater streams in tropical America, but only 10 to 30 species of insects and streams in temperate North America. Let's look at a graph. If you look at the graph, you see that we have species richness on the y-axis, the number of species increasing as we go up, and we have latitude on the x-axis as we move from the equator north towards the North Pole, you see that the number of breeding birds declines substantially. The same pattern can be seen in lizards in the United States as we move from the area around the US-Canadian border towards the Southern US, the number of species increases substantially. For landowners in the United States, this would suggest that other things being equal, people in the southern states would expect more species on their properties than landowners in the northern tier of states. There have been a number of reasons proposed for the higher species richness with declining latitude, including greater productivity and less climatic variability, but there is no clear and unequivocable reason for this trend. Altitude is another geographic factor explaining the distribution of species. Species richness generally decreases as we move from low elevations to higher elevations. So for example, if we look at this graph, we see the reptiles, amphibians, and mammals in the Cascades of Western Oregon. And once again, we have species richness on the y-axis and we have elevation on the x-axis. And you can see as we move from the area of around 1,000 feet in elevation, which has a maximum number of species, up towards the very top of the Cascades, around 8,000 or 9,000 feet, the number of species declined substantially. Now this is important from the standpoint of land management, especially from the standpoint of private landowners because much of the private land is held down at this lower region. The middle portions of this graph and the upper portions of this graph typically are federal lands, wilderness areas, and national parks. Depth in aquatic environments also regulates species richness. As we move down the water column in a large lake or in the ocean, species richness declines and it's probably related to the availability of light. Certainly, plants are constrained to what we call the photic zone where they can photosynthesize. Other primary factors regulating the diversity of biotic communities include environmental productivity, environmental heterogeneity, climatic variability, age of the environment, and environmental harshness. Species richness typically increases when the environmental productivity. The more productive a site, the more species it is likely to contain under natural conditions. Again, consider the importance of private land in this scenario. Certainly, humans originally settled the most productive areas primarily for farming and agricultural production. Environmental factors such as temperature, moisture, amount of sunlight, and nutritional factors all help explain this relationship. Plant and animal communities in both terrestrial and aquatic environments contain more species with increasing light and temperature. If we look at this slide, you can see we have the number of lizard species in the Southwestern US as a function of length of the growing season, which is an important component of productivity. Once again, species richness on the y-axis and length of the growing season in days on the x-axis, and as you move from relatively short growing seasons to very long growing seasons, and you can see the number of species increases substantially. Iridity is another important factor. As moisture becomes limited in an environment, fewer and fewer species are able to survive. For example, desert environments typically contain fewer species than environments with greater precipitation. If we look at this slide for rodents and ants in the desert Southwest, you see that the seed-eating ants, which is the upper blue line, and the seed-eating rodents, which is the lower green line, both increase as the amount of precipitation in the desert increases. As resources become more abundant in the more productive environments, there is a greater opportunity for speciation or the creation of new species over time. Increasing environmental heterogeneity also increases species diversity. Environments that are more spatially heterogeneous can be expected to accommodate extra species because they provide a greater variety of micro-habitets. It's easy to see how plant and animal communities in an area containing numerous soil types might offer favorable conditions for more species than a similar size area containing only one or a few soil types. Spatial heterogeneity is related to plant-community complexity and wildlife communities become more diverse as plant communities become more complex, especially in respect to structural diversity. So for example, if we look at forest stands or conservation buffers that contain multiple vegetation layers as such as herbs, shrubs, low and mid-layer trees and canopy contain, these areas contain more species than a similar age stand with an overstory. So for example, if we look at this graph, you can see that species richness, once again on the y-axis, increase as the vegetation diversity increases. And this is a characteristic which has been found in a number of studies primarily for birds and forest environments. Also, aquatic habitats with more vegetation diversity have greater fish species richness. Here we have a graph of fish species richness in 18 lakes in Wisconsin. And you can see that the number of species generally increases as we get more vegetation diversity in these lakes. Likewise, farms that contain spatial heterogeneity in the form of field borders, odd areas, shelter belts or fence rows, typically will contain more spatial heterogeneity and will have more species than farms without these structures. And many farming practices over the past 50 years with the advent of what we call clean farming, many of these types of areas have been removed from many of our farms in the United States and thus we have less spatially heterogeneous farming practices these days. The harshness of an environment and climatic variability also determine the number of species an area may contain. Although harshness is a relative term, certainly areas that contain extreme environmental conditions often have fewer species than areas without such extremes. So for example, grasslands with neutral pH levels in the soil such as this area in here will contain more species than soils which are acidic or soils which are basic. And so that would be one measure of environmental harshness. The range in variation environmental conditions may be just as important as the extremes. So for example, MacArthur found that a negative relationship between species richness and annual variation in temperature for birds and mammals along the west coast of North America. So this is the range in temperatures from one season to the next. However, this analysis could not be separated from latitude. More stable environments may be able to sport specialized species that would not be able to persist where there is variability in conditions or resources. Also stable environments are more likely to be saturated with species than less stable environments. When it comes to biological diversity or species richness, not all communities or ecosystems are created equal. We've all heard about the tropical rainforest and how important they are from the standpoint of conserving biological diversity. But there are other communities which are extremely important because of their productivity, perhaps because they're becoming more and more rare that we need to give special thought to from the standpoint of conserving biological diversity. Examples in particular that I'm thinking of are wetlands like the one that I'm standing beside today. When Europeans settled the United States, our continent had almost twice as many wetlands as it currently does. And in the remaining wetlands, approximately 30% of the endangered plant and animal species live in these sites. So they are extremely important from the standpoint of conserving biological diversity, not just in the United States, but worldwide. Wetlands in particular are sites that often occur in areas which are prone to development for urban expansion or perhaps for agricultural conversion. As you can see, there are numerous factors that determine the number of species in an area. This variation in species richness has important implications for conservation planning, especially on watershed or landscape scales. There are a number of important implications to keep in mind. First, some areas will be more important for conserving species in communities than others, although many sites are likely to have some unique features that are important to consider. All sites have the potential to affect species richness and community dynamics at the site level all the way up to the landscape level. Second, conservation efforts must include private lands because these areas are typically rich in the number of species for the same reasons that they were originally settled. They have high productivity, they have moderate climates, and they occur at low elevations. Some ecosystems are important because they are already rare and because they contain species that do not occur elsewhere. Some examples of this might include wetlands throughout the United States, tall grass prairie in the Midwest, longleaf pine forest in the eastern United States, southeastern US, or late successional stage forest throughout the country. Future conservation efforts are likely to seek incentives to engage private landowners in landscape level planning. As you can see, biological diversity, there are a number of factors which affect biological diversity. You can see that there are opportunities for private landowners and for state and federal agencies to assist private landowners in the conservation of biological diversity. With a better understanding of the factors which regulate biological diversity, hopefully we can be better stewards of the land. Thank you. Thank you.