Chapter 18 Conservation of Biodiversity

The 6 th Mass Extinction Extinction- when there are no longer any of the species in the world. We are currently experiencing the 6 th mass extinction. Losing approximately 50,000 species per year – amounts to 0.5% of the world’s species each year Happening over a relatively short period of time and is the first to occur since humans have been present on Earth. Rate of decline has been 100 to 1,000 times faster during the past 50 years than at any other time in human history and rivals the rates observed during the mass extinction event that eliminated the dinosaurs 65 MYA.

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Genetic Diversity Scientists want to conserve genetic diversity so that the species can survive environmental change and inbreeding will not occur. Inbreeding occurs when individuals with similar genotypes, generally relatives, breed with each other. Populations with low genetic diversity are prone to inbreeding depression – occurs when individuals with similar genotypes – typically relatives – breed with each other and produce offspring that have an impaired ability to survive and reproduce. Each parent may carry one copy of a harmful mutation – breeding may result in their offspring receiving two copies of the harmful mutation and, as a result, have poor chances of survival and reproduction. High genetic diversity – wider range of genotypes, less combinations of harmful mutations, produces a wide range of phenotypes that survive and reproduce under different environmental conditions. Cheetahs possess very low genetic diversity Result of bottleneck that occurred approximately 10,000 years ago Florida panther Inbreeding because hunting and habitat destruction shrank the population to a small group in south FL. Caused harmful heart defects and a high proportion of morphologically abnormal sperm. Scientists released 8 panthers from TX into the remaining habitat – added genetic diversity – today population estimated at individuals

Global Declines in the Genetic Diversity of Crops and Livestock United Nations notes that a majority of livestock species comes from seven species (donkeys, buffalo, cattle, goats, horses, pigs, and sheep) and four species of birds (chickens, ducks, geese, and turkeys). These species bred by humans for various characteristics Unfortunately, livestock producers have concentrated their efforts on the breeds that are most productive and much genetic variation is being lost Europe – half of the breeds that existed in 1900 are now extinct, of the remaining 43% are currently endangered North America – of the 200 breeds of domesticated animals, 80% either declining or facing extinction

Global Declines in the Genetic Diversity of Crops and Livestock A century ago – humans consumed crops composed of hundreds or thousands of unique genetic varieties Green Revolution focused on techniques that increased productivity Farmers planted fewer varieties, concentrating on those with the highest yields Fertilizers and irrigation allowed fewer but higher yielding varieties to be grown across large regions of the world Turn of twentieth century – farmers grew 8,000 varieties of apples – today, number has been reduced to 100 with even less available in the grocery store Planting only a few varieties leaves us open to crop loss if the abiotic or biotic environment changes 1970s – fungus spread through corn fields in southern US and killed half the crop The fungus was uncommon but the high-yielding corn crop was susceptible to it Following the crisis, scientists modified the high-yielding corn by adding a gene from a fungus-resistant variety Had the resistant variety not been preserved, the gene would not have been available Currently 1,400 seed storage warehouses around the world to preserve genetic diversity. Svalbard Global Seed Vault – international storage facility funded by nations and philanthropists Built into the side of a frozen mountain in the Arctic region of northern Norway Designed to resist a wide range of calamities, including natural disasters and global warming As of 2010 – more than 430,000 seed varieties stored

Categories of Endangerment When considering the status of a species, we use one of the five categories defined by the International Union for Conservation of Nature: 1. Data-deficient species – no reliable data to assess their status. May be increasing, decreasing, or stable. 2. Extinct - no known species exist today Some known to exist as recently as Threatened - species with a high risk of extinction in the future 4. Near-threatened - species that are likely to become threatened in the future 5. Least concern - species are widespread and abundant

Global Declines in Species Diversity Estimated 10 million species that currently live on Earth (from bacteria to whales), only about 50,000 have been assessed to determine whether their populations are increasing, decreasing, or stable. All groups that have been assessed – 1/3 threatened with extinction Birds - Since 1500, nearly 10,000 bird species have existed and 133 have become extinct. Today, 21% threatened or near-threatened. Mammals – of the 5,500 mammal species known to have existed after 1500, 79 are extinct – more than 1,400 species of mammals may be at risk of extinction Amphibians – experiencing greatest global declines – nearly 2,000 species of amphibians are declining around the world

HIPCO H- Habitat Loss I- Invasive Species P- Pollution C- Climate Change O- Overharvested

Habitat Loss For most species the greatest cause of decline and extinction is habitat loss. Most habitat loss is due to human development Northern spotted owl lived in old-growth forests – those dominated by trees that are hundreds of years old – in Pacific northwest and Canada Habitat ideal for nesting, roosting, and catching small mammals Removal of old trees, for lumber and housing developments, has transformed the forest into a different habitat Reduced number of owls

 US - In recent decades forested land has been increasing, although new forests have often been planted by humans and have a lower diversity of species than the original forest.  At the same time, developing countries are clearing their forests much like we did in the past – large declines of forest cover occurring in developing countries.

Invasive Species Native species – species that live in their historical range, typically where they have lived for thousands or millions of years. Alien species (exotic species)- species that live outside their historical range. Invasive species- when alien species spread rapidly across large areas. Kudzu Vine – native to Japan – introduced to US in 1876 – throughout 1900s, farmers encouraged to plant on fields to reduce erosion – herbivores do not eat – spread rapidly – vine grows over everything – currently covers 2.5 million ha in the US Zebra Mussel – native to the Black Sea and Caspian Sea in Asia – Large cargo ships unloaded their cargo in Asia and pumped seawater into their holding tanks to ensure that the ship sat low enough in the water – called ballast water – arrived in St. Lawrence and Great Lakes – loaded new cargo, no longer needed ballast – pumped ballast water out of the ship into local waters Zebra mussel produces up to 30,000 eggs – mussel spread rapidly Positive – filter the water, remove large amounts of algae and contaminants Negative – crowd out native mussel species that also need to consume the algae – can become so dense they clog intake pipes and impede the flow of water to industries and communities

Invasive Species Invasive species- when alien species spread rapidly across large areas. Silver Carp – a fish that is native to Asia but has been transported around the world to consume excess algae that accumulates in aquaculture operations and the holding ponds of sewage treatment plants Some escaped spread rapidly through Mississippi River – population expanded northward Two major concerns: Scientists worry it will outcompete native species of fish for algae Jumps out of water when startled by passing boats – can grow up to 40 lbs. and jump up to 10 feet in the air – poses safety issue to boaters

Overharvesting When individuals of a species are removed at a rate faster than the population can replace them. Ex- dodo, American bison, passenger pigeon.

Overharvesting Plant and Animal Trade Lacey Act – 1900 – one of earliest laws in US to control trade of wildlife Prohibited the transport of illegally harvested game animals, primarily birds and mammals, across state lines Convention on International Trade in Endangered Species of Wild Fauna and Flora – CITES – controls international trade of threatened plants and animals 175 country agreement Maintains a Red List – each country assigns a specific agency to monitor and regulate the import and export of animals on the list US – US Fish and Wildlife Service Despite international agreements, much plant and animal trade still occurs throughout the world

Pollution Threats to biodiversity can come from toxic contaminants such as pesticides, heavy metals, acids, and oil spills – BP oil spill – released hundreds of thousands of liters of oil dispersant, designed to break up large areas of oil into tiny droplets that can be consumed by specialized species of bacteria – toxic to many species of animals 5 Human Impacts on the Environment

Climate Change The concern is how climate change will affect temperature and precipitation around the world, and how this will impact biodiversity. In some regions, a species may be able to respond to warming temperatures and changes in precipitation by migrating to a place where the climate is well suited to the species’ niche. In other cases, this is not possible Southwestern Australia, small woodland/shrubland peninsula exists on the edge of a continent with a much larger area of subtropical desert inland– scientists expect drier conditions during next 70 years – many species of plants will not have a nearby hospitable environment where they can migrate – scientists estimate 25% of species will become extinct

Conservation Legislation Marine Mammal Protection Act- prohibits the killing of all marine mammals in the U.S. and prohibits the import or export of any marine mammal body parts. Passed in response to declining populations of many marine mammals, including polar bears, sea otters, manatees, and California Sea lions

Endangered Species Act Endangered Species Act- first passed in 1973, it authorizes the U.S. Fish and Wildlife Service to determine which species can be listed as threatened or endangered and prohibits the harming of these species. Trading these species is also illegal. The act also authorizes the government to purchase habitat that is critical to the species. Some species have experienced sufficient increases in number and have been taken off the endangered species list – American alligator, eastern Pacific population of the gray whale, bald eagle ESA often sparks controversy – organizations whose activities are restricted 1990s – logging companies wanted to log old-growth forests of the Pacific Northwest – home to the threatened northern spotted owl Many loggers viewed the ESA as a threat to their livelihood During the past decade, several politicians have attempted to weaken the ESA – strong support from the public and scientists has allowed it to retain much of its original power

Convention on Biological Diversity In 1992, nations came together and made a treaty to protect biodiversity. The treaty had three objectives: conserve biodiversity, sustainably use biodiversity, and equitably share the benefits that emerge from the commercial use of genetic resources such as pharmaceutical drugs.

Size, Shape and Connectedness When designing and managing protected areas we must consider how close to another area they should be, how large the area is, and the amount of edge habitat the area contains. Edge habitat- the area where two different communities come together, typically forming an abrupt transition. Ex. A grassy field meeting a forest. When we protect several small forests, we increase the amount of edge habitat and increase species, such as the cowbird (specialize in living at the forest edge), that can have a detrimental effect on songbirds that typically live farther inside the forest.

Biosphere Reserves Concept developed by United Nations Educational, Scientific, and Cultural Organization (UNESCO) Protected areas consisting of zones that vary in the amount of permissible human impact. Core – minimal human contact Buffer Zone – Modest amounts of human contact including tourism, environmental education, and scientific research Transition area – sustainable logging, sustainable agriculture, residences for the local human population Big Bend National Park - TX