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conservation biology

Terms in this set (25)

not all species have an equal chance of going extinct. rare species are considered particularly vulnerable to extinction a) list the three primary characteristics of rare species that make them extremely vulnerable to extinction
a species is rare if it lives in a narrow geographical range, if it occupies only one or few specialised habitats and if it is only found in small populations
b) using examples, describe how each of these characteristics is associated with heightened extinction risk.
species with narrow ranges and few populations are particularly vulnerable to global change. if species at only one or few sites in a restricted geographical area the whole range is susceptible to human activities such as exploitation, habitat disturbance, invasive species, climate change etc. and the whole range is susceptible to environmental catastrophes such as earthquakes, wildfires and disease and are particularly vulnerable to coextinctions. coextinction is the loss of one species resulting in the loss of another species that depends on it. habitat specialists are disproportionately more vulnerable to habitat loss and effects of a narrow niche requirements and small range size. rare species tend to have small population sizes. population size is a strong correlate of vulnerability. risk of extinction high in low numbers, demographic and environmental variation and loss of genetic variability. minimum viable populations below which a population is at imminent risk of extinction. two aspects; genetics (inbreeding) and population dynamics (finding a mate).
past milennia of global change provide a series of unplanned experiments for testing model predictions of biodiversity loss from climate change and improving knowledge of the process through which biodiversity responds to climate change a) what do ancient warm periods and abrupt warming events tell us about ecological responses to future climate change and their potential mitigation using conservation intervention?
past global change drivers were changes in earth's orbit around the sun and tilt on its axis and periods of abrupt warming to near inter- glacial conditions that occurred in a matter of decades along with volcanic eruptions and meteorite impacts. drivers of contemporary climate change is human population growth and demand for food, goods and services which then lead to wide-scale habitat disturbance, redistribution of species and diseases, overexploitation and climate change. mitigating future biodiversity loss can be done through computer models and conservation biology. focusing on what species and ecosystems are most vulnerable to global change and assess the effectiveness of local to global intervention strategies. early climate change mitigation is done by assessing efficacy of global scale emission reductions on biodiversity loss, most species are expected to lose 50% of ranges. reducing global emissions is an effective way to mitigate against biodiversity loss.
b) why is the detection and attribution of ecological responses to recent climate change insufficient for guiding conservation knowledge?
20th century climate change is small compared to what is being forecasted in the near future. it is hard to gather data on species range shifts over wide enough temporal scales to provide meaningful tests. conclusions for conservation are that species need to be able to shift their range boundaries in response to warming, many species will respond individualistically to warming -> new community composition, these mechanisms are unlikely to differ, at least qualitatively. in the future, improving conservation involves implementing opportunities to improve early warning systems of species loss and ecosystem change.
population viability analysis (PVA) uses demographic, environmental and where possible genetic data to assess the probability of extinction and the effectiveness of management interventions a) list the primary threatening processes affecting the population viability of the northern snake necked turtle? how does seasonality and inter-annual variability in rainfall affect these processes?
feral pig predation force, the role of density dependence for growth regulation in populations where survivorship was declining, and sustainable subsistence harvesting changes in weather, such as extended dry seasons, hugely impact the torpor of this species and extends dormancy. this is detrimental to the species as breeding decreases and animals remain underground, where they are at risk of predation of feral pigs.
b) list the primary ecological information needed to build a PVA to test the probability that the northern snake necked turtle will go extinct
we require the estimation of age structure and growth rates, survival and reproduction rates, and population size. this includes weight, sexual maturity, and reproductive status of individuals
c) what conclusions can be made from the northern snake necked turtle PVA regarding relative importance of these different extinction drivers?
it was found that survival was high in the absence of drying, harvesting and predation. interestingly, the survival remained high with drying with the removal of elocharis dulcus, a water chestnut that feral pigs feed on.
explain how principals of island biogeography theory can help land managers prioritise the size, number and location of protected areas on the indonesian island of sumatra
species-isolation and species-area relationship patterns are important when deciding protected areas. smaller areas will lower dispersal ability. these patterns are not linear, and there is a plateau in richness once area exceeds a certain size. we use natural log to linearise species patterns to find the suitable area requirement. the more isolated an island is, the less immigration there will be from source populations, and the extinction rate exceeds births, or more simply, richness will increase with more island area however decreases with more isolation. the equilibrium model of biogeography shows us that area size of islands will influence the immigration and emigration rates of an island. location must allow sufficient movement between these areas for adequate dispersal, and the number of areas are important as they will act as metapopulations.
explain the effect of losing > 40% of tropical forests in sumatra since the 1950s is likely to have had on the habitat matrix and why understanding species' use of this habitat matrix is key for conservation success.
loss of original habitat will lead to larger matrix zones, and increased edge effects on the remaining habitat. matrix would become more inhospitable with more area for predators to access, and extreme conditions such as dryness and exposure. this is important for conservation as it influences our decisions of size and location for protected zones, and whether or not corridors are needed to support the survival of species who use these areas. minimising the matrix area will lower the likelihood that species will be at a disadvantage when occupying it.
imagine you are running a conservation action planning workshop aimed at improving the viability of a threatened animal species on an island. a) describe an approach that could be used to prioritise between different conservation actions.
we must first specify our objectives in conserving this species, and whether they are met by the different action plans. these could be protecting habitat to allow safe space for the species to breed, or captive breeding/enlarging existing populations to reach minimum viable population. this also requires a method of measurement of success, such as via radio telemetry of population number. secondly, we identify the threats and opportunities of our objectives, and subsequently which actions will minimise threat, whilst maximising opportunity and benefit. finally, we assess all possible options and management options, as there will be uncertainty involved with any conservation decision. we assess the objectives of the conservation, options of how to do so, environmental and biological variables of the system, models and equations of the system dynamics, the budget constraints, the uncertainty range.
assume your focal species is threatened by predation from feral foxes which also inhabit the island. the fox population totals 10,000 individuals and has a maximum annual exponential rate of increase (rmax) of 0.82. what is the minimum proportional cull each year required to eradicate the fox population assuming no immigration?
with assuming no immigration, the minimum proportional cull year must exceed the rate of increase. P=1-(1/e^rm) therefore, p=1-(1/0.82)=-0.21 therefore, the minimum proportional cull each year required to eradicate the fox population is -0.21
assume further information to suggest that, once the fox population drops below 5,000 individuals, the maximum achievable proportional cull is 0.1 (i.e. 10%) of the population. would you recommend an eradication be attempted and why?
for eradication to occur the rate of removal must exceed the rate of increase at all population densities, there must be no chance of re-invasion and all reproductive animals must be at risk to the eradication method. further criteria is that individuals must be able to be detected at low to extremely low densities, discounted benefit cost analysis needs to favour eradication over long-term control, and a suitable socio-political environment is present. therefore, i would recommend an eradication be attempted as the fox population fits all the criteria for eradication.
describe the concept of conservation triage and present the case for why you do (or do not) consider a triage approach to be useful for focusing allocation of conservation funds.
the conservation triage involves 4 aspects of planning to help us prioritise species for conservation staying within budget. this includes value of at-risk species to society, costs, biodiversity benefits, and probability of success of conservation. this is a useful framework to use as conservation biologists as we can discern the importance (financially and ecologically) of different species at risk of extinction. realistically, this is helpful as there are numerous species at risk of extinction at present, and we must allocate our resources carefully to conserve them. on the other hand however, this can be problematic as there are ethical implications to human choice of what species are worthy of protection. it pushes the idea that some extinctions are socially acceptable. also, uncertainty is pervasive in decision making and we cant predict that the initial values and costs to conservation will remain the same. furthermore, even after establishing effective costs and means of conservation, we tend to see insufficient funding towards recovery.
how might we increase the pool of resources available for conservation through market-based instruments?
through fiscal policies such as the carbon tax which charges companies relative to emissions. payments for use of sustainable practices in production. certification of forest or fisheries products. and an innovative method is the idea of reverse auctions, where sellers place bids on what amount they are willing to do conservation work for, and essentially bid against other landowners for government support.
define and outline the difference between the following species diversity indices: species richness; species evenness; phylogenetic diversity.
species richness is the measurement of the number of different species in a community. evenness is the distribution of those species relative to the number of individuals in the entire population, a proportional evaluation rather than numerical. phylogenetic diversity is the species level genetic differences and evolutionary evidence for diversification in the community. it directly relates to number of alleles in the population, how they have adopted to survive, and gene dynamics.
using examples from the cape and wet tropics vegetation assemblages: outline when species and phylogenetic diversity are similar, and when they highlight contrasting patterns of diversity distribution.
species diversity is the number of different species present in the community, while phylogenetic diversity is the summed evolutionary age of all the species in the community, as measured by the phylogenetic tree encompassing the species present. at the wet tropics we see more similarity in the richness of species and phylogenetic diversity. however there were higher phylogenetic diversity at the periphery of these hotspots as a result of historical diversification. contrastingly, at cape flora we observed much higher species diversity than phylogenetic diversity, complementarity. this informs us that though there is phylogenetic history in these species, most of the observed diversity is a result of recent radiations.
how can this information inform on the geological scale of species migration.
by using diversity measures we can identify discrepancies in phylogenetic diversity in relation to species richness. in the wet tropics example, by modelling phylogenetic diversity into a regression and removing the species richness effects. we see that there was a biogeographic periphery of hotspots, a result of gondwanan source populations who prefer habitats in the highlands where it is cooler. contrastingly, indomalayan lineages were found in the lowlands.
as the environmental crisis worsens, conservation scientists are being forced to consider last-resort interventions to increase species resilience to changing environments. explain the scientific basis and potential risks of one of the following interventions: artificial evolution of thermal tolerance (and resilience to bleaching) in reef building corals of the great barrier reef
as coral bleaching is caused by the expulsion of microalgal symbionts, reconstructing the genome of the algal and bacterial communities that live in corals can aid in heat tolerance. these microorganisms are easily evolved in an artificial setting, with large population numbers and fast generation times, to have heat tolerance. the beneficial genes from this method of species conservation are passed on either vertically from parent to offspring, in fragmentation and outplanting, or horizontally through larvae spread into the environment. this is a combined resilience building method through manipulation of the symbionts and selective breeding.
deployment of gene editing and gene drives to suppress populations of invasive species.
gene drives force a trait through a population, against the usual rules of inheritance, potential to spread advantageous genes through an endangered population, or spread harmful genes to suppress an invasive population. gene editing finds and cuts target DNA with high precision, DNA repair systems write in new gene.
environmental DNA (eDNA) technology offers a simple, non-invasive and highly sensitive means to study threatened species and habitats that are otherwise difficult to survey. outline a potential real-world application of eDNA technology
in papua new guinea, there has been proposals for mineral deposit mining and deep sea exploration. this large scale habitat modification requires environmental assessment of the entire habitat, which can be done via eDNA sampling. as this environment is mostly unknown, unique and hard to access, by collecting eDNA we can identify the deep sea communities with minimal cost of collection. the aims in collecting the data are to create a metabarcode of the entire community and thus identify the rare species that would be at risk from the changes to habitat. the majority of work would be involved in the initial assessment, identifying every species and creating and using marine species. this will then be useful for future impact assessments and monitoring changes that have occurred after the mining project commences.
what resources are needed to carry out an eDNA survey of a threatened species or habitats?
for either the species or all species within the habitat, we require a reference genetic database for identification of eDNA collected. this in turn will require gene analysis equipment, sediment cores, and sterile handling to minimise loss or contamination of the DNA. as DNA has a quick degradation rate once collected, we will need on site labs and analysis equipment to immediately assess the samples. importantly, we need funding and political support to engage in this work.
how to calculate observed heterozygosity (H0)
H0 = total number of heterozygous individuals/total number of individuals
how to calculate F-statistics
Fis=He-Ho/He and Fst=Ht-He/Ht where Ho = average observed heterozygosity of an individual in a population and He = average expected heterozygosity (2pq) of an individual in a population under random mating and Ht = expected heterozygosity of an individual in the total sample under random mating
how to calculate the expected distribution of genotypes in population data assuming random mating
p^2 + 2pq + q^2 where A = p, B = q, AA = p^2, AB = pq + qp = 2pq and BB = q^2
what is the assumptions of the hardy-weinberg principle?
1) mating in random
2) organism in question is diploid
3) reproduction is sexual
4) generations are non-overlapping
5) population size is very large
6) migration is negligible
7) mutation can be ignored
8) the alleles in question are neutral
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