Tropical Ecology and Everglades Biology Review

Comprehensive flashcards generated from lectures covering tropical ecology fundamentals, ecological field sampling methods, tropical savannas, and South Florida ecosystem dynamics including the Everglades and Big Cypress Swamp.

What proportion of Earth's terrestrial species and marine species like corals and mangroves are found in the tropics?

The tropics host $80\%$ of the planet's terrestrial species and over $95\%$ of its corals and mangroves.

How are the tropics geographically defined by latitude?

The tropics are defined as the region located between $23^\circ 27'\text{N}$ and $23^\circ 27'\text{S}$.

What three climatic variables are used to classify ecosystems in Holdridge's Life Zones system?

Mean annual biotemperature, total annual precipitation, and the ratio of mean potential evapotranspiration to mean annual precipitation.

What data forms the basis of the Köppen-Geiger climate classification system?

The distribution of natural vegetation determined using monthly temperature and precipitation data.

What is the average January minimum temperature for the tropical region of South Florida?

$54^\circ\text{F}$.

How does the line transect method measure vegetation or organisms?

A measured line is laid across an environmental gradient, and all species touching the line (or at specific points) are recorded to measure presence or absence.

What formula is used in the Lincoln Index to calculate animal population abundance?

$\frac{n_1 \times n_2}{n_3}$, where $n_1$ is the total marked in catch 1, $n_2$ is the total caught in catch 2, and $n_3$ is the number of marked individuals recaptured in catch 2.

How is Ash-Free Weight measured when determining organic biomass?

The sample is oxidized in an oven at $500^\circ\text{C}$ until only inorganic ash remains.

What is the mathematical formula for Simpson's Diversity ($D$), and what does a low $D$ value indicate?

$D = \frac{N(N-1)}{\sum n(n-1)}$; a low $D$ value suggests pollution, recent colonization, or agricultural management.

What were the original geographic dimensions of the historic Everglades marshy arc?

It was $30$ to $50\text{ miles}$ wide and extended about $100\text{ miles}$ from Lake Okeechobee to the mangrove fringes of Whitewater Bay and Florida Bay.

How do Marl and Peat soils differ in their origin and composition in the Everglades?

Marl is calcitic mud made from degraded periphyton containing calcium carbonate particles, whereas Peat consists of accumulated dead plant matter formed during long hydroperiods.

What distinguishes Everglades peat from Loxahatchee peat?

Everglades peat is formed from sawgrass detritus and is dark brown to black (often containing fire soot), while Loxahatchee peat is formed in deeper sloughs from water lilies and other plants, appearing light brown to reddish.

What are the two types of wet prairies in the Everglades, and how do they differ?

Marl prairies sit on limestone bedrock with high plant diversity (up to $100\text{ species}$) and solution holes; Peatland wet prairies are deeper, less diverse, and dominated by plants such as maidencane, Tracy's beak rush, or spikerush.

What ecological role do sloughs play in the Everglades marsh system?

Sloughs are the deepest marsh communities and serve as the main avenues of water flow through the Everglades.

What is the largest named tree island in the Everglades, and what is its surface area?

Skinner's Island (also known as Johnny Buck), which covers $650\text{ acres}$.

What three geological/ecological processes form tree islands in the Everglades?

Fixed (trees rooting on elevated rock formations or ancient refuse), Pop-up (buoyant peat lifted to the surface by trapped methane gas), and Strand (sawgrass strands invaded by shrubs).

How do Tropical Hardwood Hammocks differ from other Everglades tree islands?

Hammocks occur on slightly elevated areas with mature hardwood vegetation dominated by species of tropical origin.

Which tree species dominates the canopy of South Florida pinelands?

South Florida slash pine (Pinus elliottii var. densa).

What fraction of the Earth's total land surface is classified as savanna?

$\frac{1}{5}$ of the Earth's land surface.

What defines Nonseasonal, Seasonal, and Hyperseasonal tropical savannas?

Nonseasonal savannas form due to poor, rapidly draining soil despite heavy rain; Seasonal savannas have distinct wet and dry seasons; Hyperseasonal savannas experience an extreme dry season followed by a saturating wet season.

What are four typical xerophytic plant adaptations found in tropical savannas?

Thick waxy cuticles, water storage structures, deep root systems accessing aquifers, and $C_4$ or CAM photosynthetic pathways.

What is a pyrophyte, and how does fire maintain savannas?

A pyrophyte is a plant adapted to withstand fire; fire clears above-ground brush to reduce competition for fast-growing grasses, releases soil nutrients, and prevents succession into dry forest.

What three dietary categories classify African megafauna herbivores in savannas?

Grazers (feed on grass), Browsers (feed on tree leaves), and Mixed Foragers (feed on both).

What specific human impacts have historically degraded the Big Cypress Swamp?

Logging of cypress and pines in the 1940s and 1950s, plant collecting, off-road vehicle ruts, hydrological drainage, peat soil loss, fire seasonality changes, highway construction (Alligator Alley and Tamiami Trail), oil and gas extraction, and invasive species like Brazilian pepper.