1. Read- Biodiversity and Restoration Ecology PDF

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"In the process of helping the earth to heal, we help ourselves. If we see the earth bleeding from the loss of topsoil, biodiversity, or drought and desertification, and if we help reclaim or save what is lost—for instance, through regeneration of degraded forests—the planet will help us in our self-healing and indeed survival." — Wangari Maathai

Differentiate between the three types of biodiversity that are a concern in maintaining a functional ecosystem. Describe the six ways that species have been impacted by human actions. Provide examples of how the focus on biodiversity protection has been on species, while a newer approach takes into account the multiple species and habitats of ecosystems.

1. Why is succession important to ecosystems? 2. What does HIPPCO represent? 3. What is being done to protect species from extinction due to human influence?

Biodiversity is considered one of Earth’s precious resources. Biodiversity, the variety of life, exists at three levels: genetic, species, and ecological. This trinity of biotic components comprises the underlying and interrelated infrastructure of Earth. Earth’s biodiversity continues to be threatened by the ever-increasing growth of the human population and the resulting impact on the planet through resource use.

Conservation management involves genetic diversity within a species, species diversity within a given area—either species richness or species evenness—and ecological biodiversity.

One type of biodiversity is genetic biodiversity. As discussed in Chapter 3, a low variation of genes within a population can increase the chances of negative traits being passed on or decrease the number of offspring. However, there are other concerns relating to gene expression and frequency within the genetic diversity of a species. For example, because of differences in habitats, there can be specialization to the local region that is not beneficial for the greater range of the species. In addition, there can be overdominance of non-beneficial traits by random chance (gene flow), inbreeding, or a bottleneck from a catastrophic event (Meffe & Carroll, 1997). Genetic diversity is important because it means that a wider range of traits are available for selection, allowing for increased species adaptability to an environment.

A second type of biodiversity is species biodiversity. A species is defined as a group of reproductively isolated individuals. As discussed in Chapter 3, the distinction between species and subspecies can be controversial. The total number of species is largely unknown with worldwide estimates from experts ranging from 10 to 100 million (Wilson, 2010). The estimated number in each kingdom is also not evaluated with equivalent criteria among different biological disciplines. For example, a microbiologist might classify a species of archaebacteria, a distinct type of bacteria, as having more genetic diversity than would a zoologist (Mora, Tittensor, Adl, Simpson, & Worm, 2011). Current research indicates that the class with the most species is insects. Insects play a vital role as an important food source in addition to plant pollination and dispersal and maintaining soil health. The majority of known species have only a scientific name rather than a common name because scientists are continually exploring new areas and finding new species (Wilson, 2010). Of the nonmicroscopic species discovered from 2006–2007, “75 percent were invertebrates, 7 percent were vertebrates, and 11 percent were plants” (Wilson, 2010, p.55). In 2013, scientists identified 8,000 new species, including both microscopic and non-microscopic species (Bakalar, 2014). The fact that additional species continue to be identified does not mean the impacts of anthropogenic (human-caused) extinction are less of a concern. On the contrary, with increased destruction of habitat, it is believed that many species are lost before they have been identified or the important niche they filled is discovered. One group that works to track the status of endangered species is the International Union for Conservation of Nature (IUCN), which estimates that it would need to triple its current knowledge of the species that are known to exist to be fully comprehensive (Stuart, Wilson, McNeely, Mittenmeier, & Rodriguez, 2010).

"The great ecosystems are like complex tapestries - a million complicated threads, interwoven, make up the whole picture. Nature can cope with small rents in the fabric; it can even, after a time, cope with major disasters like floods, fires, and earthquakes." —Gerald Durrell

Ecological biodiversity refers to the overall variety of ecosystems, each of which has a unique structure and function. This includes the number of niches, trophic levels, and food webs that were outlined in Chapter 3. Variation of ecosystems across a landscape is caused by variation in soil, slope (gradient), aspect (facing north, south, east, or west), elevation, climate, and geology. This is not to say that the ecology of an area does not change. In fact, periodic disturbances can be both detrimental and beneficial to ecosystems in the long run.

The process of ecosystem change is called succession and is divided into primary and secondary succession. Early successional organisms, such as lichen, can break down rock and enable the next plant types by creating soil. Without additional disturbances, lichens may be followed by the midsuccessional nonwoody plants and early successional trees that can tolerate the sun well, which are then followed by late successional plants that need shade. This progression is a process of competition for resources as environmental conditions change (Bazzaz, 1979). Unexpected disturbances (natural disasters such as fire, floods, and wind storms) can delay or reset succession. These disturbances that result in primary or secondary succession create a patchwork of plant communities with varying levels of development, which increases habitat types. Increased habitat types allow for a greater diversity of species (Gleen-Lewin, Peet, & Veblen, 1992). This means ecosystems are not like a well-organized bookshelf or playlist on a phone—instead, there is some randomness to the order. Some species fare better in the chaos, while others thrive in stability. Organisms that are best adapted to disturbance are generalists that have a high level of adaptability to change. Other factors can increase a species’ chances of surviving a disturbance, including aggressive dispersal (increases the population size and range), a long lifespan, a high population growth rate, and the ability to reproduce asexually. Organisms might not have all of these characteristics, but likely have some combination of them. According to Bazzaz (1979), early successional plants typically have a high transpiration and photosynthetic rate, seeds that can lie dormant for years in a seed bank until conditions are right, and seeds that respond to changing temperature and high levels of light. Over time, depending on the resilience of the organism, this can result in a monoculture such as a cottonwood stand. Cottonwoods are the main type of vegetation in their habitat because they predominate over other trees, although they can still be displaced. Cottonwoods can germinate from seed and from the roots, resulting in clusters of trees with identical genetics. Having one dominant type of vegetation is not necessarily negative. Aspen trees are great for pulpwood and respond well to clear-cuts by being the dominant tree in the area. In terms of managing for species, it is important to know the level of disturbance and which species do better at what level. Even aspen can benefit by leaving some trees in a clear-cut, an area where all trees are uniformly cut down, to potentially seed and increase genetic diversity (Long & Mock, 2012). In other species, such as some grasses and pines, low intensity fire can increase plant regeneration.

However, fire levels are an important consideration for ultimate management. For example, a ground fire that clears the vegetation on the ground has a very different impact when compared to a crown fire that destroys ground vegetation as well as the top foliage of trees (Meffe & Carroll, 1997). Human manipulation such as prescribed burns, rotational grazing, and multiple forest management regimes can duplicate these natural benefits. For example, a stand of early successional trees that need sun, such as aspen, respond well to clear-cuts, while a late successional tree requiring shade, like mahogany, does better with selective cutting that leaves the forest canopy to shade the tree (Cunningham & Cunningham, 2012). For late successional trees, there have also been experiments with mixing agriculture and forestry as in the ejidal forest lands in Mexico (Ejidal Forest Producers Organization, 1999). Even if there are few environmental disturbances, plant communities will shift. Late plant communities have an advantage over early- to mid-successional communities under stable conditions. For example, late successional plants have a slower photosynthetic and transpiration rate, their seeds do not need to respond to light, and they are efficient in low light, so they can take over early succession species (Bazzaz, 1979).

Questions Students May Have Why is succession important to ecosystems? Ecosystems are dynamic groupings that thrive under varying levels of change. What might be viewed as destruction provides a chance for new growth.

Primary succession includes disturbances that remove soil at the base level, such as the bottom of the ocean. Volcanoes can completely cover the soil with lava, so that the soil needs to be broken down again. Glaciers can also impact the soil by scraping it off the bedrock or completely changing the soil through deposition. An example of anthropogenic primary succession would be paving a road or scraping the bottom of the ocean with a trawler to catch fish. These changes may last longer than normal disturbances and have a negative impact on the ecosystem. With increased human transportation, these areas of high disturbance increase the likelihood of invasive exotic species. On a local scale, this may increase diversity, but it is not native and, therefore, results in decreasing the diversity of species native to the ecosystem. Organisms that are only found in a specific area are called endemic and are at a high risk of becoming extinct when exotic species are introduced. Secondary succession, on the other hand, is a disturbance after which the soil is still intact. Disturbance factors such as fire, grazing, and floods are unpredictable, but they do not completely destroy the soil, which makes them examples of secondary succession. This type of disturbance can leave the soil with many nutrients, providing a jump-start to regrowth, particularly for early successional plants. For example, during a flood or fire disturbance, there can be increased levels of nutrients after the destruction. See the fire case study for more information.

Extinction is a natural process. The problem is that the level of extinction has increased over the past several centuries, due in large part to human activities, either directly or indirectly. For example, in 1975, the extinction rate “was 100 per year [with an expected increase to] 20,000 species per year [in] 2000” (Smith, 2013, p. 268). Scientists identify six main causes of extinction that humans may influence, which is simplified to the acronym HIPPCO. The acronym stands for habitat loss, invasive species, population growth, pollution, climate change, and overharvesting.

The first anthropogenic reason for the loss of species is habitat loss. The reason for habitat loss may be development. Unlike early development where cities grew outward in circles prior to the advent of the automobile, automobiles now allow for a checkerboard pattern of land use that causes the fragmentation of habitat (Grimm, 2004). Roads can result in roadkill, whereby animals are killed while traveling migratory routes or searching for food. Research in South Dakota has shown that elk choose habitats near the least used roads that have places to hide, which suggests a potential management plan for decreasing elk roadkill (Montgomery, Roloff, & Millspaugh, 2012). There have been studies in the tropical rainforests in Brazil where, in undisturbed areas, if there was an opening in the forest canopy from construction of a road, it seemed to create a boundary for populations of birds as long as the canopy of trees above the road were missing (Develey & Stouffer, 2001). Pipelines in Alaska can also cause habitat fragmentation, so pipes are buried or elevated to reduce this effect (Dunne & Quinn, 2009).

Nonnative species that successfully outcompete indigenous species for limited resources are classified as invasive or exotic species. A nonnative species that can have multiple progeny at a time, has a long lifespan, and features single-parent or vegetative reproduction will greatly exceed its carrying capacity and is more likely to become an invasive species, particularly if the new habitat is similar to its native habitat. Some habitats are also more at risk, such as early successional communities that have recently been disturbed and that feature an absence of predators or competitors (Meffe & Carroll, 1997). This is why states and countries may limit the importation of particular plants or pets. For example, in Arizona, owners of African hedgehogs are required to obtain a permit since this species does not have any known predators (Thompson, 2006). Similarly, Hawaii restricts some plants from being taken to other states because of risk of introducing the plant into the wild and becoming the dominant vegetation. It is easier to control the potential introduction than combat a successful invasion as described by the key–lock model, which shows that it can take a while for favorable conditions to establish an invasive species but, once established, it is able to spread much faster (Heger & Trepl, 2003).

Not all introduced species become invasive if the population numbers can remain stable. However, if the species lacks natural population controls such as predators or if there is a disturbance, there can be a transition to more favorable conditions so the species can become invasive. Some invasive species were originally introduced to help solve a problem before it was discovered there was a problem with population control. For example, kudzu was introduced in the 1930s to control erosion in the southern United States; in the 1970s, it became invasive, even covering up abandoned houses (Swearinger, Slattery, Reshetiloff, & Zwicker, 2010).

As the human population has increased, there has been greater competition for resources. Humans have increased development, leading to increased encounters with wildlife. Sometimes, species find ways to use human structures to replace habitat. One such case arose in Austin, Texas when the public demanded that bats living under a local bridge be removed. Merlin Tuttle, a bat researcher, photographer, and founder of Bat Conservation International (BCI), then decided to move BCI to Austin to educate people about protecting the bats. “Today Austin generates millions of dollars in local revenue from visitors who come to see the spectacle of 1.5 million bats” (Scardina & Flocken, 2012, p. 165). On the other hand, the demand for specific resources has also led to habitats being transformed into, for instance, a field of only one crop, thus resulting in decreased species biodiversity. This is not a new problem. Archeological evidence has shown that by 1400, Easter Island was deforested to the point that a species of palm went extinct (Redman, 1999). The ecological footprint discussed in Chapter 2 is one way to quantify this concern to stimulate appropriate policies (“A Framework,” 2012).

Pollution can be classified as biodegradable or nonbiodegradable. Biodegradable pollution can be broken down into separate parts such as fertilizers becoming the basic elements of nitrogen, phosphorous, and sulfur. Nonbiodegradable pollution includes metals such as mercury and lead because, even when they are broken down to the atomic level, they remain the same substance. There is also light, sound, and heat pollution that can be harmful to wildlife. When considering pollution, the first thing that might come to mind is garbage. Even remote regions of the world are not free from this type of pollution. For example, turtles mistake plastic bags in the ocean for jellyfish; they eat the bags and become sick and can even die. There are islands of garbage in which there is more plastic than plankton (Freebody, 2009). People can alleviate the pollution issue by participating in cleanup projects to prevent garbage from entering the ocean, recycling plastic, and using alternatives to plastic bags (Freebody, 2009; Sluka, 2013). Air pollution can also negatively impact a habitat. Such has been the case with the black triangle region of Europe (Germany, Poland, and the Czech Republic), which is surrounded by mountain ranges. The mountains there trap the air pollution, allowing concentration and the creation of acid rain. Acid rain typically has only the acidity level of a lemon or vinegar, but this can affect soil composition, cause defoliation, and lead to increased weathering of stone. The main source of this

pollution is soot, which is released from low-quality, coal-fired plants. International agreements and funding for pollution prevention technology to control pollution have helped forest recover since the early 1990s (Strub-Aeschbacher, 2002). Farming practices, beyond altering habitat, can have far-reaching impacts through pollution. The use of biocides can lead to the destruction of species for which they were not intended. For example, DDT, a pesticide used to control the mosquito population and reduce malaria, traveled up the food chain from cockroaches to rats to cats and caused a myriad of problems (O'Shaughnessy, 2008). Moreover, there is increasing evidence of pesticides that were intended for destructive insects killed beneficial insects such as pollinating butterflies and bees (Brittain, Vighi, Bommarco, Settele, & Potts, 2010). A chemical in herbicides, soaps, and cosmetics called atrazine acts as an endocrine disrupter that causes male tadpoles to become feminized or decreases their testosterone levels and fertility. Studies in the Potomac basin (where the water flows from Maryland, West Virginia, Pennsylvania, and the District of Columbia) show the suburban frog populations are at most risk (Barringer, 2008). This example shows how common household items can become pollution. Another growing problem, which will be discussed in a later chapter, is pharmaceuticals being disposed of improperly and becoming water pollution. Excess fertilizers washed into waterways can cause an algae bloom. An algae bloom, as mentioned in Chapter 6, is created when excess nutrients in the water result in a high population of algae to the point that the fish cannot consume it all before the algae dies. If the population of algae is within natural limits, it is very beneficial to the environment because it is such a large source of oxygen on the planet. However, the high decomposition rate from the dead algae lowers the oxygen levels in the water, resulting in a dead zone for fish and other aquatic organisms. Some forms of algae can create a red tide phenomenon (the algae looks red), which can cause rashes on swimmers and has an adverse impact on water quality. Eating some species of red tide-contaminated fish can cause digestion or respiratory problems. Because of the increased incidence of algae blooms, “Oregon, California, Vermont, and Florida have active programs to alert the public about these events” (Smith, Blanchard, & Bargu, 2014, p. 39), while there is a need for such interventions in other locations such as southern Louisiana. There are many other types of pollution that may not be obviously disruptive. Propellers of ships create loud noises that make it difficult for whales to communicate and can increa...