Chapter 23: Conservation Biology Flashcards
How has the military base Fort Bragg helped with conservation?
it has helped preserve the longleaf pine savanna and helped save the endangered red-cockaded woodpecker because it prevented large areas from being converted to farmland, forestry, or housing
Contributing Factors of Longleaf Pine Savanna decline
-fire suppression, human population growth, and clearing for plantations of other trees, such as loblolly pine
-oringinally covered 30 million hectares, now it covers only 3% of that
What does the red-cockaded woodpecker done to adapt to the savanna?
-they require mature, living pines for nesting
What has reduced the red-cockaded woodpecker population size?
loss of habitat, which makes them vulnerable to genetic drift, inbreeding, and extinction
How many red-cockaded woodpeckers were killed by Hurricane Hugo in 1989 in one population?
70%
How many species are listed threathened with extinction on the Red List of Threatened Species?
23,250 species
Conservation Biology
-is an integrative discipline that applies the principles of ecology to the protection of biodeiversity
-the scientific study of biodiversity, how human activites impact it, and how to maintain it and prevent its loss
What is the key to conservation biology?
integrative approaches that involve farmers, landowners, the US military, and business community
How do people rely on biodiversity?
We use hundreds of domesticated and wild species for food, fuel, fiber, medicines, building materials, spices, and decorative items
Ecosystem Services
natural processes that sustain life, such as water purification, soil formation, pollination of crops, climate regulation, and flood control
Alfred Russel Wallace
warned in 1869 that humanity was at risk of obscuring the record of past evolution by bringing about extinctions
When and why did the Ecologists’ Union branch off from the Ecological Society of America?
-1948
-they wanted to focus on preservation of species
What must conservation decisions be based on?
sound scientific analysis
Is biodiversity increasing or decreasing globally?
decreasing
Alwyn Gentry
-devoted his life to identifying, classifying, and mapping plant diversity in Central and South America
-eyewitness to plant species extinctions and identified endemic species
What is the extinction rate of mammals and birds from the fossil record?
one species every 200 years
What is the average species life span and how does that relate to the current extinction rate?
-Life Span: 1-10 million years
-Average Life Span with current extinction rate: 10 thousand years (1 extinction per year)
How much higher were extinction rates in the 20th century than the background rate?
100 to 1000 times higher
What do estimates of current extinction rates rely on?
-the species-area relationship
-changes in the threat status of species
-rates of population decline or range contraction of common species
Can extremely small populations serve the same ecological function as larger populations?
No
What did the colonization of the Pacific islands cause for the bird populations?
extinction of up to 8,000 species of birds
Why are small populations the focus of much reserach?
they are more vulnerable to genetic, demographic, and encironemtneal stochasticity
Extinction Vortex
a cyclic chain of events causes a small population to decline even furthur and become ever more vulnerable to processes that lead to extinction
What does a spatial approach track?
changes in a species range
What did a study of 173 declining mammal species worldwide show?
that these species had lost 68% of their range area
What does the extinction of a species do to the community?
-consequence for that species’ predators, prey, and mutualistic partners
-may bring about secondary extinctions and affects ecosystem function
The _____ the interactions of a species in the food web, the _____ the effect of its removal
stronger, greater
What type of effects do range expansions have and how do they occur?
-positive and negative effects that occur because movement and introduction of species has increased over the last century
What effects do non-natives have on biodiversity?
-negative effects
-reduce the range of native species who may already be declining
-hurst specialist for a certain habitat the most
What is the spread of introduced species and native generalists and the decline of native specialists leading to?
taxonomic homogenization
What is a positive effect non-natives can have?
provide habitat or food for rare species (rare cases)
What do species introductions increase?
regional biodiversity because the number of non-natives introduced to a region typically exceeds the number of native species that become extinct
What habitats are particuarly vulnerable to invasions and extinctions?
islands
What did the survey of American Samoa find (Cowie 2001)?
-found 19 of 42 native species of land snails and 12 non-native species
-high abundance of non-natives with natives declining
-Non-native predators contributed to the decline of natives
-homogenization of land snails is widespread on Pacific Islands
Rahel (2000)
-examined the change in number of species shared between all possible pairs of the lower 48 states
-On average, pairs of states shared 15 or more species than they did at the time of European Colonization
What are primary threats to biodiversity?
habitat loss, invasive species, overexplotation, pollution, disease, and climate change
What contributed to the extinction of the Pyrenean ibex?
overexplotation and competition with domesticated livestock
How many mammal species are currently threatened with extinction?
1,197 species
What are the primary threats to extinction of mammals?
loss of habitat, unregulated hunting, accidental mortality, pollution, and disease
How much of Earth’s land surface and marine ecosystems have been modified by humans?
-60% of land and all marine ecosystems
How much of Earth’s primary production is done by Humans?
25%
What is the most important factor contributing to global declines in biodiversity?
impact of human activities on natural habitat
Habitat loss
conversion of an ecosystem to another use
Habitat fragmentation
breaking up continuous habitat into patches amid a human-dominated landscape
Habitat degradation
changes that reduce quality of the habitat for many, but not all, species
How much of the Atlantic Forest of Brazil has coincided with Brazil’s human population?
70%
How much of the Atlantic Forest of Brazil had been cleared?
92%
What is the theory as to why no bird extinctions have occured in the Atlantic Forest of Brazil?
time lag
Causes of habitat degradation
invasive species, overexplotation, and pollution
Invasive species
non-native, introduced species that sustain growing populations and have large effects on communitites
How much of the world’s Unionoida population is in North America?
1/3
What are the effects of introducing the Nile Perch into Lake Victoria?
reduced diversity and abundance of the native cichlid fishes
-about 600 cichlid species have been recorded, most are endemic
-Nile Perch predation has resulted in the extinction of 200 species of cichlid
What increases vulnerability to invasive species?
habitat loss and degradation
What percentage of Hawaiian tropical dry forests have been reduced by?
-90%
Hickman et al. (2010)
-measured the impact of Nitrogen cycling in kudzu plants
-nitrogen mineralizatioin reates increrased and more nitric oxide was released from the soils
What is the best stratefy for combating invasive species?
prevent their arrival
As human population increases and natural habitat shrinks, the ____ of many species from the wild has become unsustainable
harvesting
What has removed large vertebrate faunas in tropical forests?
unregulated hunting
What has led to declines in abundance and size of top predators in the oceans?
overfishing
Bycatch
Forr every ton of fish caught by commercial trawlers, 1 to 4 tons of other marine life is brough onboard
What is the effect of repeated trawling of the sea bottom?
degradation of benthic habitat and impacts species such as corals and sponges
What is the speed of habitat recovery following trawling?
slow
What is the relationship between market value and harvesting?
increases in market values increases harvesting, leading to overharvesting
Approach to preventing overexplotation
determine sustainable levels of harvest and establish regualtory mechanisms to achieve those levels
What are other factors that contribute to declinging populations?
air and water pollution, climate change, diseases
Pollutants
cause physiological stress and contribute to habitat degradation and biodiversity loss
Endocrine-disrupting contaminants
interfere with reproduction, neurological development, and immune function in mammals
What are ECDs?
some are ersistant organic pollutants that can enter marine food webs and undergo bioaccumulation and biomagnification
Ross 2006
-showed that levels of PCBs and PBDEs were very high in marine mammals in British columbia
What are some chemicals that are found in marine organisims?
PBDEs (flame retardants)
EDCs
What has been the effect of global warming?
-hundreds of species have shifted their ranges in response to global warming
-only a few cases of direct endangerment, expected to increase
Is habitat loss greater in the tropics or polar zones?
tropics
Is climate change greater in the tropics or the polar zones?
polar zones
Should conservation biology focus on species or habitat?
Both are important. Must understand species biology in order to protect its habitat
What does the US Endangered Species Act mandate?
identification and protection of critical habitats for each species listed
Genetic Analyses
-small populations are vulnerable to geneitc drift and inbreeding, which result in loss of variability and fixation of deletrious alleles
-these effects increase the risk of extinction and can ruin efforts to conserve a species
Genetic Rescue
-used to save the florida panther population in the early 1990s after it decreased to 25
-they released 8 texas pumas into southern florida
-panther numbers tripled, levels of genetic variation doubled, and frequency of genetic abnormalities decreased
How are molecular genetics used to identify sources of ilegal wildlife products?
Example: identification of illegally harvested whale species in meat that was labeled as either dolphin or Southern Hemisphere mink whale, which are illegal to hunt
Forensic conservation biology
demand for ivory led to widespread slaughter and decline of African elephants
-was banned but then illegal trade started
-used DNA (PCR) to track where tusks came from
Population Viability Analysis (PVA)
allows ecologists to assess extinction risks and evaluate management options
-probabilites of population persistence are calculated under varous scenarios
What is PVA used for?
-assess risk of extinction of a population
-identify particularly vulnerable age or stage classes
-determine how many individuals are needed to establish a new population
-determine a safe number of animals to harvest
What is the problem with models?
unknown critical factors can be left out so they have be constantly be refined and tested
Ex situ Conservation
-removal of extremely small populations from the wild and propagate it in sheltered conditions
Problems with Ex Situ programs
very expensive and have had limited success
What is the main legislation to protect threatened species?
Endangered Species Act (ESA)
Fish and Wildlife Service and National Marine FIsheries Service
are the agencies that list species, identify critical habitat, draft recovery plans, and carry out actions to increase abundance of the species
How many native species are protected by the ESA?
1,300
Convention on Internation Trade in Endangered Species of Wild Fauna and Flora
regulates trade in endangered species as a result of an international treaty
Convention of Biological Diveristy
acknowedges that declining biodiversity is a problem shared by all people
-framework for nations to develop conservation plans
What can help maximize protected biodiversity with limited resources?
prioritizing species
What does species rarity depend on?
geographic range, habitat specificity, and population size
How many different types of species rarity is there?
7
What do IUCN assements take into account?
population size, geographic area occupied by the species, rate of decline, and risk of extinction
Surrogate Species
prootecting habitat for one species, such as the red-cockaded woodpecker can result in protection of other species
Flagship species
a charismatic organisim that people will want to give protection to , such as the mountain gorilla
Umbrella Species
protection of its habitat will serve as an umbrella to protect many other species with similar habitat requirements
Walters et al.
tested the hypothesis that lack of suitable habitat was limiting woodpecker populations by bulding artificial nest cavities and placing them in clusters
Cooperative Breeders
males born in previous years help their parents raise young
