BIOL 327 Sampling, Replication, and Ecology Final Notes

A complete set of 100 vocabulary flashcards covering sampling methods, abiotic and biotic factors, population growth models, species interactions, plant life strategies, and landscape ecology based on the lecture notes provided.

Sampling

A technique used by ecologists because it is usually impossible to measure an entire population, aiming to provide an estimate of population size with the smallest confidence limits at the lowest cost.

Systematic sampling

A method where samples are collected at regular intervals, such as traps placed every $5\,\text{m}$ along a transect line.

Advantage of Systematic sampling

It is easier than random sampling and is often desirable when one needs to sample evenly across an entire habitat.

Disadvantage of Systematic sampling

This method often produces biased results.

Simple random sampling

A sampling method where every sample unit has an equal probability of being selected.

Advantage of Simple random sampling

It is the simplest way to achieve an unbiased sample.

Disadvantage of Simple random sampling

If the sample size is too small, this method might miss out on some environment types altogether.

Stratified random sampling

A method where the area is divided into different strata and each stratum is sampled at random.

Advantage of Stratified random sampling

It ensures all habitat types are represented, reduces sampling bias, and often provides more precise estimates.

Stratum

A distinct subdivision or layer of an area defined for sampling purposes, such as rocky vs non-rocky habitats for tuatara.

Pseudo replications

The act of treating non-independent variables as if they are independent in statistical tests.

Effect of Pseudo replication on variance

Failing to account for non-independence reduces the variance in the data, creating the illusion of a highly precise result.

Problem with one treated and one untreated site

The traps used are considered subsamples rather than true replicates, as many differences between the sites other than the treatment (e.g., poisoning) likely affect abundance.

Better experimental design for replication

Choosing several sites (e.g., $20$) and randomly assigning half to a treatment so they are spatially intermingled with untreated controls.

Abiotic factors

Non-living environmental conditions, such as temperature and moisture, that determine species distribution by defining tolerance limits.

Habitat stability

The requirement that a habitat provides the conditions needed for survival, growth, and reproduction; extreme conditions prevent population persistence.

Potential niche

The overlap of environmental conditions (e.g., moisture and temperature) under which a population can persist.

Moisture variables

Key abiotic factors including precipitation, relative humidity, and soil moisture.

Temperature variables

Key abiotic factors including Mean Annual Temperature (MAT), summer maximum, winter soil temps, number of frost days, and season of ice cover.

Correlative models

Models that use species occurrence data and environmental variables to predict suitable habitats.

Climatic envelope

The identified set of climatic conditions where a species can potentially occur, identified using correlative models.

Strength of correlative models

They are relatively easy to build and useful for predicting species invasions.

Weakness of correlative models

They rely on correlation, which does not equal causation.

Mechanist models

Models that use physiology, tolerance limits, and development rates to predict species distributions.

Argentine ant development requirement

A mechanist model requirement of approximately $445$ degree-days above $15.9\,^\circ\text{C}$.

Biotic influences

Interactions with other species, such as competition or predation, that restrict or expand species distributions and alter abundance.

Fundamental niche

The potential climatic combinations where a species could persist if no other species (e.g., predators or competitors) affected it.

Realised niche

The specific locations where a species exists in a climate suitable for persistence, often restricted by biotic interactions.

Facilitation

Any interaction that has a positive effect on the receiving party, which can be positive (mutualism), neutral (commensalism), or negative (antagonistic).

Nurse plants

Plants used in restoration ecology, like Manuka and Kohuhu, that improve survival for other natives by reducing frost, sun exposure, and grass competition.

Lichens

Mutualistic organisms consisting of fungi with algae growing within them; the fungus receives sugars and the algae receives water and protection.

Competition

An interaction where both species experience negative effects, often resulting in the restriction of realised niches.

Wethey (2002) experiment

A study showing that Semibalanus balanoides outcompeted Chthamalus fragilis in northern areas, determining its range boundaries.

Transplant experiment result (Chthamalus)

When transplanted into areas lacking its competitor, the species survived beyond its normal range limit.

Specialist predators

Predators that rely on a narrow range of prey, often limited to one or a few closely related species.

Generalist predators

Predators that feed on a wide variety of different prey species.

Extent of occurrence (EOO)

The total area enclosed by the outermost known occurrences of a species; a small value indicates greater extinction risk.

Area of occupancy (AOO)

The specific area occupied within a geographic range; it is considered a better indicator of species status than EOO.

Resolution effect on AOO

With finer resolution subunits, the measured value of the area of occupancy reduces.

Rapoport's rule

The observation that species at higher latitudes tend to have larger geographic ranges than species in the tropics.

Explanations for Rapoport's rule

Greater climatic variability at high latitudes, better dispersal following glaciation, and less competition/greater ecological generalisation.

Density-dependent population growth

Population growth limited by resources; as density increases, individuals compete more, causing growth to slow and stabilise.

Exponential growth model

A density-independent model of population growth occurring when resources are unlimited, producing a j-shape curve.

Per-capita growth rate (Exponential)

In an exponential growth model, this rate remains constant even as the population increases.

Logistic growth model

A density-dependent model where growth slows as the population size approaches the carrying capacity, producing an s-shaped curve.

Carrying capacity ($K$)

The maximum population size that an environment can sustain, around which populations stabilise in a logistic model.

Contest competition model

A growth model where dominant individuals monopolise resources, resulting in a fixed number of successful individuals.

Scramble competition model

A growth model where resources are shared among all individuals, potentially leading to population crashes at high densities.

Boom-and-bust cycles

Population fluctuations often caused by scramble competition when densities become extremely high and survival drops.

Allee effects

A phenomenon where population growth is negative at low density due to difficulty finding mates or reduced group defense.

Consequences of Allee effects

Small populations risk extinction even without harvesting and the creation of unstable equilibria.

Lotka–Volterra Predator–Prey Model

A mathematical model describing predator–prey dynamics where populations cycle through time.

Lotka–Volterra Assumption: Prey

The assumption that the prey population grows exponentially in the absence of predators.

Lotka–Volterra Assumption: Predators

The assumption that the predator population depends on prey and predator consumption increases with prey abundance.

Lynx–hare dynamics

A classic example used to illustrate the predictions of the Lotka–Volterra Predator–Prey Model.

Predation rate

The number or proportion of prey consumed by predators per unit time.

Measurements of predation rate

Can be expressed as prey killed per predator per unit time or total prey killed per unit area per unit time.

Direct observation

A method of measuring predation by recording kills; often used for large, visible predators.

Limitation of direct observation

It is difficult to perform in dense habitats, many events are missed, and it is subject to observer bias.

Prey removal experiments

A method to estimate predation by measuring changes in prey abundance over time after marking and counting them.

Limitation of prey removal experiments

It is hard to separate predation from other mortality like disease or emigration, and it may alter natural behaviour.

Functional response

A description of how the number of prey consumed by an individual predator changes with prey density.

Type I Functional Response

A response where prey consumption increases linearly with prey density, suggesting no handling time limits.

Example of Type I response

$\text{Daphnia}$ feeding on yeast cells.

Handling time

The time a predator spends catching, killing, and consuming prey, which limits the rate of consumption in Type II and III responses.

Type II Functional Response

A response where consumption increases rapidly then levels off due to handling time; it is the most common response in nature.

Example of Type II response

Damselfly nymphs feeding on $\text{Daphnia}$.Line

Type III Functional Response

A response where consumption is low at low prey densities but increases rapidly at intermediate densities.

Causes of Type III response

Prey switching, learning, and the development of search images by predators.

Herbivory

The consumption of plant tissues by animals, driving ecological and evolutionary interactions through plant defense and tolerance.

Monophagous herbivores

Specialist herbivores that evolve detoxification mechanisms to overcome specific plant defences.

Oligophagous herbivores

Herbivores that feed on a restricted range of related plant species.

Polyphagous herbivores

Generalist herbivores that are more affected by a broad range of chemical defences.

Physical plant defences

Traits such as thorns, trichomes, and tough leaves that deter herbivores.

Chemical plant defense

The use of toxins and secondary metabolites to reduce herbivory.

Resistance (Plants)

Traits that reduce herbivore preference or performance, thereby reducing the amount of damage a plant receives.

Tolerance (Plants)

The ability of a plant to maintain its fitness level despite experiencing herbivore damage.

Compensation

Growth or physiological changes that allow a plant to recover after being damaged by an herbivore.

Induced defences

Plant defences that are only activated after an herbivore attack has occurred.

Facultative mutualism

A mutualistic interaction where the species benefit from each other but are not strictly dependent on the interaction for survival.

Obligate mutualism

A mutualistic interaction where the species are physically or survival-dependent on each other.

Mycorrhizal fungi and plant roots

A mutualism where fungi receive carbon from plants, and plants receive phosphorus and nitrogen.

Occurrence of mycorrhizal mutualism

This interaction occurs in approximately $80\,\%$ of all terrestrial plants.

Inter-specific competition

Competition between individuals of different species for limiting resources like light, water, and nutrients.

Tilman's competition model

A model focusing on resource ratios, resource depletion, and long-term equilibrium outcomes.

$R^*$ (Minimum resource requirement)

In Tilman\'s model, the species that can survive at the lowest resource level is considered the superior competitor.

Grime’s CSR model

A model explaining plant competition and community structure based on how species respond to stress and disturbance.

Stress (Grime’s definition)

Environmental factors that limit plant production, such as low light, low nutrients, or temperature extremes.

Disturbance (Grime’s definition)

Factors that destroy plant biomass, such as herbivory, fire, frost, or trampling.

Competitor (C strategy)

A plant strategy adapted to low stress and low disturbance, characterized by high growth rates and space pre-emption.

Stress tolerator (S strategy)

A plant strategy adapted to high stress and low disturbance, characterized by slow, sustained growth and a long time to maturity.

Ruderal (R strategy)

A plant strategy adapted to low stress and high disturbance, characterized by good seed dispersal and early reproduction.

Omnivory

An interaction occurring when species feed across multiple trophic levels, blurring strict linear food chains.

Top-down control

Regulation of the ecosystem where predators at high trophic levels control the abundance of lower levels.

Bottom-up control

Regulation of the ecosystem where energy or nutrients limit producers, affecting the entire system higher up.

Janzen–Connell hypothesis

A theory suggesting specialist enemies maintain diversity by causing higher mortality in seeds and seedlings near parent plants.

Distance-dependent mortality

A mechanism where seedlings have higher survival rates the further they are located from the parent plant.

Density-dependent mortality (Community)

A mechanism where death rates are higher in areas where seeds or seedlings are clustered together.

Reserve design principles (Island Biogeography)

A set of guidelines suggesting large, compact, and connected reserves are better than small, elongated, or isolated ones.

SLOSS debate

An ecological debate over whether a Single Large Or Several Small reserves are better for maximizing biodiversity conservation.