BIOL 421 - Exam 1
Considering resource use and resource availability in a community, what type of changes in these parameters might increase the invasibility of a community?
an increase in resource availability may make a community easier to invade resource use = resource availability
Compare and contrast the three major schools of thought that shaped American conservation biology since the 1800's.
- Romantic and Resource Conservation ethic = essentially human centered, environment is worth saving because it benefits humans - Evolutionary Ecological Land ethic = preserving these natural communities because they are worth it without offering a benefit to humans
Conservation biology is often viewed as a "crisis-discipline". List three characteristics of the discipline that accompany this description. Name at least one benefit and one drawback of continuing to promote Conservation Biology as a "crisis-discipline".
- tolerate uncertainty - emergency decision making - lack of established policy or law Benefit = Immediate action to solve a problem since it is a pressing issue Drawback = Because of the immediate action the issue might bot be resolved correctly due to lack of evidence
From Soule 1985, what are at least 3 primary defining characteristics of the field of Conservation Biology? Provide a brief statement describing each.
1) Crisis discipline - Contains a pressing timeline where problems are far along - tolerating uncertainty: may have to make decisions with limited data 2) Similarity to natural resource fields - distinct in not being economic and utilitarian based - more species = biota as a whole - holistic and multidisciplinary 3)Time scale - long range viability of whole systems and species including their evolutionary potential - persistence of diversity with little or no help from humans
What does your textbook propose as the three guiding principles of Conservation Biology? Briefly discuss each
1) Evolution is the basic axiom that unites all of biology (evolutionary play) - only reasonable mechanism able to explain the patterns of biodiversity 2) Ecological world is dynamic and large non equilibrial (ecological theater) - Ecosystems are open to the exchange of materials and species and to the flux of energy 3) Human presence must be included in conservation planning - Native human cultures are a historical part of natural history and the ecological landscape
In the Channel Island example we discussed in class, how would you answer the high school teacher's question : Why the pig? Provide at least 4 points.
1) Fox is native, endemic, keystone species that coevolved with island communities 2) Pig is a strong interactor which could have a negative impact on other species and ecosystem 3) Pig has no natural predator and has not coevolved with island communities 4) Pig's life history outpaces the fox which allows it to have an evolutionary advantage
Franklin et al 2002 suggest that it is important to correctly categorize how habitat is being altered, what 4 cases do they distinguish? (remember that the first slide of this had a error, I corrected this in Thursday 14th lecture)
1) Habitat loss without fragmentation 2) Habitat loss with fragmentation 3) Fragmentation 4) Edge effects, fragmentation, change in habitat quality
What three key pieces of information did MacArthur and Wilson have in hand as they began to develop their ETIB?
1) Larger islands tend to have more species 2) Very remote islands tend to have fewer species 3) Number of species is roughly constant even though there is a turnover in species
Name and describe three major schools of thought that have shaped American conservation biology since the 1800's. Provide the name of at least one person that is associated with each.
1) Romantic/Transcendental - emphasized the spiritual and aesthetic value of nature and "wildlife: - Ralph Waldo Emerson = connection with nature is essential for a person's growth - Henry David Thoreau = simple living in the natural environment - John Muir = influenced creation of National Parks 2) Resource Conservation Ethic - efficient, scientifically informed management of nature for human benefit "multiple use" - Theodore Roosevelt = set aside millions of acres for national parks, forests, etc 3) Evolutionary Ecological Land Ethic -natural communities are worth preserving without reference to any derived human benefits -Aldo Leopold = beginning of modern conservation biology "biota as a whole"
Brook et al (TREE 2008) present different models of how individual threats can lead to biodiversity loss. Briefly describe the different potential relationships between threatening processes as presented by these authors. You can use a simple graph to present your ideas.
3 factors: habitat loss, harvesting and climate change
Approximately how many humans are on the planet today? What is the historical trajectory of human population growth and how does this relate to the field of Conservation Biology?
7.5 billion humans currently United Nations predicts by 2050 9.7 billion The population growth is causing the 6th mass extinction; the more people that are on earth the less habitable space for organisms
What does the Shannon Index aim to capture in terms of overall biodiversity and how would this measure help you prioritize your conservation efforts?
Accounts for the number of species (richness) and evenness
Describe Dr. Vredenburg's fish removal experiment and the results. Briefly discuss the biological and economic management implications of his findings.
After removal of the trout, the tadpole population fully recovered and the adult juveniles semi recovered
What is the Allee effect? Provide a brief example of such an effect in a population.
Allee effects are broadly defined as decline in individual fitness at low population size or density that can result in critical population thresholds below which populations crash to extinction
How are alpha, gamma, and beta diversity estimated. What do these measures tell us about how diversity is spatially distributed and how might they be used in conservation planning.
Alpha = species richness, local focus area - count the number of species in the focus area and take the average Gamma = total number of species across larger area that encompasses individual focal areas
How did the Aral Sea change in size from 1964 to the late 2000s? Why did this change occur? List at least 4 biological, ecological, or commercial/economic outcomes of this change.
Aral sea was dried out, because it lost it primary water inlet. water was diverted to sustain a cotton industry - led to 60 percent of human population losing drinking water - led to collapse of fishing, cotton, and meat industries, - collapse of aquatic species due to increasing salinity - higher concentration of minerals in water
Where will most of the changes in our current understanding of taxonomic diversity come, that is, which groups are currently the most poorly described?
Bacteria = 0.5 % described Viruses = 1% described Fungi = 5% described Nematoda = 6% described
Describe several ways that biodiversity hotspots have been identified in the literature highlighted in lecture, what is the cautionary suggestion from Ceballos and Erlich 2008?
Biodiversity hotspots have been identified as endemism, richness and threat level Cautionary suggestion: Shouldn't focus on just one area for conservation. Should be able to prioritize in all different wats that conserve the most
What 'filters' does an exotic species have to overcome in the process of establishing itself in a new community? Which of these filters is particularly impacted by humans and how?
Biogeographic filter (human impacted ) Physiological filter and Biotic filter Humans impact biogeographic filter by being able to mobilize and move a species past a barrier that they would not be able to cross without human help - example = humans transplanting a species population from the US to the UK
Explain Elton's "Biotic Resistance Hypothesis". Assuming this relationship exists, draw what you would expect to observe in communities with varying levels of species richness (x-axis) and occurance/incidence of an invasive species (y-axis).
Biotic resistance hypothesis described the chances of an invasive species to be successful in introduced environments - states that species in diverse environments are more resistant to invasive species
What does the Rarity-Weighted Richness Index aim to capture in terms of overall biodiversity and how would this measure help you prioritize your conservation efforts?
Combines alpha and beta diversity into a single number and weighs the level or rarity for the species in the area Areas with a larger RWRI should be prioritized higher for conservation efforts
Why does the shape of the 'diversity-function' relationship matter in terms of the consequences of biodiversity loss?
Creates a barometer of sorts that can be used to predict how many species can be lost before the function of the ecosystem will be changed
According to Soule et al. 2005, how well does current policy deal with species interactions and what should management professionals aim for with regards to 'strong interactors'?
Current laws and policies dealing with biodiversity protection and management do not specifically address the ecological effectiveness of strongly interacting species Soule argues that conservationists need to consider how to best provide for such species and the processes they mediate in accord with the intent of these laws
Provide a succinct definition of "edge effects". List four environmental or biological characteristics that might differ between edge and core habitat.
Diverse physical and biological phenomena associated with abrupt, artificial boundaries of habitat fragmentation - changes in microclimate - exposure to disturbance - alter predator prey relationships - allows for spread of disease and invasive species
Briefly describe the Tilman experiments we discussed in lecture and what they tell us about 'diversity-stability' and 'diversity-function'.
Diverse plots are stable and vary less over time - increase biofuel: plots with more diversity increased biofuel more than monoculture
What are the hierarchical levels in which diversity is organized and which level receives most attention in conservation? Do you see that particular focus as a strength or weakness, why
Ecosystem, community, species, population, gene Species level receives most attention = they are the fundamental components of biodiversity Both a strength and weakness. -contributes so much to the natural world; lose focus on species = no point to conserve -human centered world will not survive without species diversity -place too much focus on one level = lose insight from others that could help us strengthen our world's diversity
Why is it important to consider edge effects in assessing habitat availability?
Even if there is a large area of protected habitat, there may not be a large amount of suitable habitat for animals that require interior areas if there is a poor edge to area ration (length of edge/area of interior) - important to take into account when managing habitat
What is the history of fish stocking in the Sierra's and why weren't fish introductions initially suspected as being a major cause of decline in frogs?
Fish were introduced in the Sierra's in the 1890s by horseback, but the frog population did not decline till the 1970s -because in the 1960s we finally started to stock the alpine lakes by plane which was more efficient than by horseback - after a decade, the fish had a change to establish a healthy population but that took away food, nutrients, and habitat away from the frogs and tadpoles
From examination of past extinction events, there appear to be at least some life history/ecological traits that are correlated with extinction risk. Name 4 of these and their general relationship with extinction risk. Feel free to use simple graphs with labeled axes to present your ideas. Choose one of these general trait-extinction risk relationships and describe a species that either does or does not conform to the general relationship you describe.
Geographic range = if you have a small range, likely to go extinct Home range = if you need a large uninterrupted tract of land to do stuff in, you are likely to go extinct Population density = a large dense population is less likely to go extinct Trophic level = higher trophic levels are likely to go extinct specialization = specialized species are more likely to go extinct
What is the difference between habitat loss and habitat degredation?
Habitat loss = impacts are severe that all species are somehow impacted degradation = impacts some species, not all, with the eventual possibility to restore the area
The pigs and foxes on Santa Cruz Island provide an example of 'apparent competition'. Describe the trophic dynamics on this island that lead to this situation.
High number of foxes and low number of eagles. after the pig introduction, there was a decline in the fox population and an increase in the eagle population - in order to restore the fox population, the pigs and eagles would need to be eradicated - pigs = eradicated = fox population would go extinct because the eagles would begin to prey on the foxes
Orians (1994) coined the term 'Homogocene' to describe the era that we are currently in. What is he trying to describe with this term and how might you measure the existence of this phenomenon?
Homogocene = humans have broken global barriers allowing species to move between masses and aquatic environments in a way they could not before increases the alpha diversity but decreases the beta diversity
Using cheatgrass as an example, describe at least one ecosystem-level change that is being caused by this invasive species. Does this alteration change the invasibility of the grassland community? If so, how?
Invasion of cheatgrass lowers ecosystem diversity which increases invisibility as described by Elton - change in resource availability --> native species disappear --> space left open for invaders
Provide a succinct definition of habitat fragmentation.
Large expanse of habitat, transformed into smaller, isolated areas, unlike the original. Discontinuity of resource distribution that affects survival of species
How do you reconcile Levine's (2000) greenhouse-seed experiments and his surveys of natural communities? What do these experiments suggest about the invasibility of natural communities?
Levine's greenhouse experiment show that diverse communities were more resistant to invasion from non natives - failed to take into account species turnover = large part of how invasive species establish Natural communities especially those that have a high diversity experience large amounts of species turnover - provides ample opportunities for invasive to take hold
We discussed 4 hypothetical relationships between species richness (as a measure of diversity) and ecosystem function. Graph them and provide a brief interpretation of each.
Linear: Richness increases as function increases, vice versa = least probable relationship Rivet: Richness does not increase until it hits a certain level of function Redundancy: Richness evens out when function is at its peak Idosyncratic: Richness and function show no discernible pattern
Tillman showed that ecosystems with higher species richness are more stable. Why might diverse ecosystems be more stable over time?
Loss of species influences instability in a negative feedback loop Possible that high richness will include species that encourage redundancy and stability Diverse communities use a resource completely, meaning less resources for the invasive species to use
List 4 ways in which habitat fragmentation differs from natural heterogeneity.
Natural landscapes are divided into patches; diversity in habitats are in dynamic equilibrium, species may or not be able to adjust to rapid change Patches and matrix in natural habitats tend to have complex internal structure; matrix tends to be simplified contrasts are more intense in fragmented habitats
What is a "patch"? What is the "matrix"?
Patch = native habitat that is undeveloped Matrix = entirely inhospitable, outside area of patch
What do McGarigal et al. (2005) suggest are the characteristic steps in the progression of habitat fragmentation? Briefly describe each.
Perforation = small holes of development Dissection = connecting small holes with roads and other development Subdivison = habitat becoming physically subdivided Shrinkage and attrition = each group of development consistently increases area of development
Describe two ways of quantifying habitat fragmentation and what characteristics of fragmented habitat they are intended to reflect.
Proximity index - accounts for diversity, patch distance - able to see connectedness of system Edge to area ratio = length of edge/area - does not count isolation distance - considers patch shape and size
According to research done by Dr. Tyrone Hayes, how does the pesticide atrazine impact individual frogs at various developmental stages and what are the population-level implications?
Shrinks reproductive organs and produces a teste/ovary tissue Frogs become hermaphroditic and males stopped producing testosterone = made them feminized caused a low reproductive output with levels of atrazine found in normal water
From the basic ETIB model, compare species richness and turnover rates in small-far and large-near islands.
Small far island = lowest number of species and an intermediate rate of turnover Large near islands = largest number of species and intermediate number of turnover
What are the characteristics of a 'strong interactor' or keystone species as detailed by Soule et al. 2005?
Species on which other species depend on, if it were removed the ecosystem would collapse suggests certain species have huge impact on rest of ecosystem - top predators, ecosystem engineers, pollinators
What is a succinct definition of biodiversity?
The number (species richness) and relative abundance of unites of each level of the hierarchy of life
What is an extinction debt? Provide an example. How does this concept help guide conservation efforts?
There is a large amount of habitat destruction, without associated extinction, eventually that population will go extinct
What habitat/region(s) are projected to experience the most habitat loss by 2050 and why is this of particular significance to biodiversity?
Tropical, subtropical coniferous forest, tropical grassland and broadleaf forest Bad because these areas have the highest levels of biodiversity
Why is alpha taxonomy, the description and naming of species, important in conservation biology?
Used to classify organisms hierarchically in ways that reflect their evolutionary history Classifications are constructed in which the higher taxonomic categories contain all of the descendants on their most recent ancestor, but no other species (monophyletic)
Describe an indirect ecosystem service and what would have to be put in place by humans to replace this service.
water storage and recharge - water enters an aquifer can be replaced by; large water treatment plants and levees