Larval Dispersal and Population Connectivity

Flashcards reviewing core vocabulary, concepts, models, and empirical studies related to marine larval dispersal, population connectivity, metapopulations, and biogeography.

Open Population

A population structure where all adult populations contribute to a common larval pool, which in turn provides recruits to all populations, allowing large populations to buffer small ones against demographic stochasticity.

Closed Population

A population structure where each adult population contributes to a distinct larval pool without influencing other populations demographically or genetically.

Sewall Wright's $F_{ST}$ Test

A statistic that compares the amount of genetic variation within each sampled population to the variation partitioned among populations, providing an indication of overall genetic divergence among subpopulations.

Wright's $F_{ST}$ Formula

The formula $F_{ST} = \frac{H_T - H_S}{H_T}$, where $H_T$ represents heterozygosity in the total population and $H_S$ represents the average heterozygosity of individual subpopulation samples.

Metapopulation Connectivity

The rate of exchange of individuals among populations via dispersal, which links populations together and can allow sources to maintain sink populations.

Rescue Effect

The maintenance of populations in low-suitability patches (sinks) through continuous dispersal of individuals from adult populations in high-quality patches (sources).

Metapopulation Model Continuum

A classification system for metapopulations ranging across patch sizes (from all small to all large) and patch connectivity/isolation levels (patchy, classical, mainland-island, and nonequilibrium).

Type 1 Population

Populations where dispersal is high and populations are strongly linked demographically, requiring strong natural selection to produce genetic differentiation.

Type 2 Population

Populations that are ecologically isolated but genetically connected, where dispersal is sufficient to limit differentiation of neutral genes, but low enough to allow weaker natural selection to cause differentiation.

Type 3 Population

Effectively closed populations that exhibit a significant global $F_{ST}$ and a marked departure from random expectations for neutral genes.

Isolation by Distance (IBD)

A genetic pattern where genetic differentiation increases with geographic distance, typical of linearly distributed populations where dispersal occurs primarily between adjacent areas.

Fecundity-Size Relationship

The demographic principle that larger individual fish produce disproportionately more offspring than smaller fish (e.g., a $23.6\text{ in}$ vermilion rockfish produces $1.7 \times 10^6$ young compared to $150,000$ produced by a $14.6\text{ in}$ fish).

Pineda Larval Dispersal Framework

A multi-scale conceptual model describing how offshore larval pools are winnowed down by physical transport processes and micro-hydrodynamic, behavioral, and substrate availability processes to dictate settlement and recruitment.

Biogeographic Province (10% Endemism)

A distinct geographic region defined by marine community boundaries where at least $10\text{\%}$ of species present are endemic to that region.

Thin Layers

Oceanographic regions of enhanced shear and high vertical velocities that accumulate passive, buoyant particles and weakly swimming organisms, concentrating food biomass and potentially increasing larval developmental rates.