Exam Flashcards
“50-500” rule
The 50/500 rule was made in 1980 by Australian geneticists to define a minimum lower threshold to prevent genetic loss (viable effective population size (N(e)). 50= minimum population size to combat inbreeding, a minimum. Of 500 individuals needed to reduce genetic drift. Population size is extremely important in evaluating conservation priorities for a species. Small populations are at risk of going extinct because of demographic stochasticity and genetic drift.
Theoretical application: When attempting to recover extremely depleted populations, there is direct conservation efforts to get the adult population above 50 (>50), and continue recovery efforts until populations is above 500.
“SLOSS” debate
The SLOSS is a ecology and conservation debate during the 1970 and 1980 regarding weather single large or several small reserves are superior in conserving biodiversity in a fragmented habitat.
Why is it relevant?
Biological corridors
Wildlife corridors are connections across the landscape that link up areas of habitat. They support natural processes that occur in a healthy environment, including the movement of species to find resources, such as food and water.
They are very important for conservation of biodiversity and ecosystems, as they allow species to reproduce and ensure exchange of individuals and genes between several populations. They contribute to genetic diversity of species and recolonisation of environments in the event of a disturbance. Ne = Population now. Difficult to use in marine concervation because we don’t know larval dispersal.
Population viability analysis
PVA is mathematical/ ecological models that estimate changes in population size (N) over time based on life history and demographic rates, environmental factors, population pressures (threats) and genetic factors. It is applied in conservation biology to predict future scenarios for population growth and decline, as well as compare alternative options for their management. PVAs can be used as a basis for listing species as threatened and endangered under IUCN red list.
Critically endangered species
A taxon is “Critically Endangered” when it is facing an extremely high risk of extinction in the wild in the immediate future, as defined by any of the following criteria:
Population reduction:
- Observed population reduction of 80-90 % over the last 10 years or 3 generations.
- The species is found than less than 100 km2 area or 10 km2.
- Less than 250 mature individuals in the population
- Quantitve analysis showing the probability of extinction in the wild is at least 50 % over 10 years or three generations.
Phylogenetic diversity
Diversity that includes how long the genetic distance is between species (Phylogenetic tree). Areas that have high phylogenetic differences (owl and fox) will also be an area with high species diversity. High species diversity supports better and more ecosystem function. Focusing on maximising phylogenetic diversity in conservation because it on average maximizes the protection many taxa
Triple jeopardy
Triple jeopardy is a combination of social and biological factors that increase an animals extinction risk. Fish is particularly prone to extinction if it has a small range, is not abundant were it is found, and has specialised dieter, habitat, physiological or reproductive requirements. Some marine animals like sharks and rays face triple jeopardy due to their marine habitat. Large animals are typically more comen in this category as they take a long time to reproduce and mature, they can be hunted at a faster rate than they can reproduce. Whale shark example.
Congruency
Similarity between difrent taxa, what might be good for one taxa might not be good for everyone. To make efffcent concervation you need congurancy (overlap) of taxas.
Bioaccumulation
Bioaccumulation is a process of accumulation of chemicals in an organism that takes place if the rate of intake exceeds the rate of excretion. Chemicals are introduced into the organism through exposure to the abiotic environment (soil, water, air) or as dietary intake (trophic transfer). Marine organisms that are filter feeders such as mussels are used to measure and monitor the consequences of industrial discharge as they are placed out in cages (they respond rapidly to changes in water quality and rapidly absorbs heavy metals etc.).
mBACI” sampling design
Multiple before and after control Impact (mBACI), The purpose of which is to determine whether a particular disturbance (natural or human induced) causes a change in the population or assemblage. The method involves 2 or more controls and 2 or more impact sites. Good because of special replication
Representative area
Identifying the main geographic gradients in an area (Species composition, habitat type etc.), and then choosing sites from the different habitat types. By establishing reserves at the different locations that represent different habitat types and species composition, a range of different communities and a greater biodiversity are protected.
o This require that we have a great deal of information to describe the major spatial patterns in community structure.
o Strategies used in reserving at the GBR
The Representative Areas Program (RAP) aims to enhance protection of the region’s biodiversity by developing a network of no-take areas that represents the range of habitats and communities within the Marine Park.
Recruitment overfishing
Taking such a high proportion of the breeding stock that there is no longer enough juvenile recruitment to sustain the fishery or allow it to recover. Bigger K selected species are especially exposed to recruitment overfishing as they have few offspring and take a long time to reach maturity, so they cannot reproduce enough to replenish the population. The result of this is collapsed fisheries and species populations. This is an important focus area within conservation to put regulation on harvest amounts and have oversight of how much fish is being fished to monitor the abundance and regulate thereafter.
Eutrophication
Accumulation of nutrients in the water results in algae dominating because of high nutrient availability. Fertilizer runoff to marine ecosystems can lead to algae bloom that now dominates. This can lead to bottom-up control. It results in deterioration of water quality and the depletion of dissolved oxygen in water, Algal blooms limit light penetration, reducing growth and causing die-offs of plants in littoral zones while also lowering the success of predators that need light to pursue and catch prey. Bacterial metabolism increases as benthic plants die, leading to conditions of hypoxia (low oxygen) and in extreme cases, anoxia (oxygen too low to support animals = dead zones). Eutrophication areas can eventually become dead zones.
Dispersal kernel
Dispersal distance, (Distance and probability of dicpersal) the Euclidian distance between ‘start’ and ‘end’ points of a dispersal event, is recog-nized as a fundamental characteristic of the dispersal process and defined as the movement of dispers-ers (diaspores, propagules, gametes, or dis-persing) to where they establish.
Dispersal kernels are useful to MPA design (i.e. how far apart should MPA’s be?) and fisheries management as they can inform potential of population replenishment to surrounding unprotected or open fishing areas. For threatened species, they can also inform ‘rescue effect’ potential.
Ecological extinction
Ecological extinction is the reduction of population densities to the point that the species no longer plays the same ecological role in communities. This is probably the most widespread and serious form of extinction in the marine environment. However, ultimately the ecosystem will collapse as the system runs out of ecologically equivalent species.
Local extinction
Local extinction is the disappearance of a species in certain areas or loss of sub- populations, particularly in relation to exploitation and/or local pollution. Local extinction may not be a problem, provided that there is a source of juveniles for recovery. However, it can be a major problem when it concerns keystone species.