Chapter 56 Conservation Biology and Global Change

Chapter 56 Conservation Biology and Global Change 56.1 Human Activity threatens Biodiversity on Earth Conservation Biology: The discipline that combines ecology, physiology, molecular biology, genetics, and evolution in order to conserve the diversity of life on Earth and can further connect to other things like economics and politics. 3 Types of diversity: Genetics: Focuses not only on the genetics within a population, but also between populations because when a population goes extinct the adaptive potential of a species is reduced for the future.  Species: These are the number of species in each environment or across the biosphere. o Two sources of concern for Conservationist:  Endangered Species: Species that face extinction through all or much of its natural range.  Threatened Species: Species that are likely to become endangered in the future.  Ecosystem: Third tier of diversity. When one species goes extinct then many other species suffer, and many current ecosystems are heavily altered or are rapidly changing because of human activity. Why should we care? 1. Many species help contribute to our welfare with medicines, food, and clothes to the point that they have become a natural resource. 2. Without certain genes that other organisms produce, we will not be able to continue to grow our welfare. 3. Ethical and moral reasons for caring for living things.  Ecosystem services: All the services and processes through which the natural ecosystem helps sustain human life such as clean air and water, pollinating crops, preserving soil. (Also known as all the things that nature does for free) As the biodiversity on Earth declines, we also hurt ourselves. 4 Main threats to Biodiversity: 1. Habitat loss: This is the greatest threat because reduced habitat means species cannot move and may lead to extinction of a population. This can occur over wide regions and causes habitat fragmentation. 2. Introduced Species: These species, regardless of intention, when introduced to a new habitat, can grow unchecked leading to disruptions in the community they are introduced to. Many were introduced with good intentions, and all led to disastrous consequences. 3. Overharvesting: Harvesting organisms at rates that exceed reproduction and is especially bad with smaller populations or in populations with low reproduction rates. Through molecular genetics, scientists are finding ways to track where overharvesting is taking place. 4. Global Change: Altering the ecosystems ranging from regional to global scales. Disruptions include alteration of climates, Atmospheric chemistry, narrowing of broad ecosystems. Things like acid rain. Scientists are currently researching ways to restore extinct species to certain ecosystems, but currently all attempts have failed even in cloning experiments. 56.2 Population conservation focuses on population size, genetic diversity, and critical habitats. Extinction vortex: A downward population spiral in which inbreeding and genetic drift combine to cause a small population to shrink and if not reversed go extinct. Inbreeding can reduce overall fitness and loss of genetic variability and genetic drift causes random variation in the allele frequencies of the population which can also reduce fitness. The minimum viable population: The minimum population size at which a species can sustain its members. Most often is calculated using computers with many factors. To calculate MVP successfully the researchers, need to determine the effective population size based on the males and females that successfully bred. This effective population size can be smaller than the total population. The equation to determine for EPS or Ne: 4 N f∗N M N e= N + N f m Nf= # of females Nm= # of males Always a fraction of the total population Determining these values is essential to preserving genetic diversity enough to adapt to environmental changes. Migration between populations can help increase the MVP and EPS of different populations. Environmental factors, however, can still cause the decline of a population even when above MVP and has a high EPS. Part of saving species requires a balancing of demands that sometimes conflict with saving the species. Most often these are related to habitat use and conservation ecologists strive for win-win solutions and saving critical ecological roles. Ecologists do this by identifying keystone species and considering the community as a whole. 56.3 Landscapes and regional conservation help sustain biodiversity. Landscapes: An area containing several different ecosystems linked by the exchange of energy, materials, or organisms. These are influenced by physical factors. Edges of ecosystems have different conditions than the two ecosystems on either side of it. Some thrive in such communities because they can benefit from both ecosystems and some like the edges created by humans and other species can decline because those species are adapted to the interior of the ecosystem. In isolated populations, a movement corridor is necessary. A movement corridor is a narrow strip or clumps of habitat that connect isolated populations and can help sustain biodiversity. Movement corridors also help by facilitating dispersal and reducing inbreeding but can allow diseases to spread through populations. The highest conservation priority is the biodiversity hotspots where many endemic species (species not found elsewhere) and endangered species live. Conservation is not always a simple task, and many conservationists focus on a smaller area than desired, there is a bias toward conserving vertebrates and plants, and the ever-present threat of climate change. Nature reserves have lots to consider, questions such as preventing disturbances or allowing them to happen. Many countries are adapting and moving to the concept of zone reserves. These reserves are extensive regions that include areas that are relatively undisturbed by human activity surrounded by areas that have been changed by human activity and used for economic gain. Marine reserves are less common despite fish populations declining and as more countries adopt these, they can potentially help fish populations rebound. Some ecologists are looking to conserve even n urban settings with urban ecology which focus on organisms in urban settings with cities being the ecological labs. 56.4 Earth is changing rapidly as a result of human activity. There are 3 main ways human activity is affecting the environment. Nutrient enrichment:    The idea that one part of the biosphere loses nutrients and another part gain these. This alters chemical cycles in both. Example: Farming and crops moving to feed people and eventually exhaust the soil and things such as fertilizer increase the nitrogen content of the soil Problems arise when nutrient levels rise above the critical levels or the amount of added nutrients that can be added and absorbed by the environment without affecting environmental integrity.  Added nutrients can create dead zones in rivers, lakes and oceans and causes eutrophication. Toxins in the environment:   Toxins can often be stored as fat in animals and the concentration increases each trophic level you go up. Called Biological Magnification: A process by which retained substances become more concentrated at each higher tropic level of the food chain leading to the highest trophic level being the most affected. 3 main types of toxins: o Industrial compounds and pesticides: Things such as DDT and Chlorate hydrocarbons o Pharmaceutical: Released mostly through excretion or improper disposal which creates low concentrations in the water supply o Plastics and microplastics Climate change and rising CO2 levels:     This is causing a greenhouse effect in which there is a rise in global temperatures. Carbon sinks are becoming carbon emitters. Many of the effects of these things are currently being represented by computer models. Also, in addition to rising carbon dioxide levels, there is reduction of the ozone layer, and it is really apparent over the arctic in the spring. 56.5 Sustainable development can improve human lives while conserving biodiversity Saving everything is impossible so aiming for sustainability is the goal Aiming for sustainability requires identifying key patch habitats and major conservation goals that will help conserve other things Across the world a growing concept is sustainable development: Economic development that meets the needs of people without hindering the ability of future generations to meet their needs Sustainable development requires a multilayered and multidisciplinary approach and requires continuous decisions and work to come about The goal of sustainable development and other pursuits within biology are a physical manifestation of our biophilia or our love of life.