everglades

Everglades dimesions

50 miles wide average depth of 6 inches

everglades source

lake okeechobee

Where does the soil come from?

Bedrock from limestone, sand from ancient sand dune and humus from organic plant debris

Why is everglades nutrient poor?

Limestone and sandy soil provides little nutrients besides calcium and high precipitation leaches nutrients from plant litter and loses it through porous soil

Subtropical blend of

temperate and tropical

Diverse plant communities

glades - sawgrass (sedge), wet prairies, freshwater slough, pineland, hammock - hardwoods, cypress head, mangrove swamp

Glades

sawgrass=sedge. seasons: winter and summer

sawgrass marshes

sawgrass isnt a true grass but member of the sedge family. Sawgrass once covered the northern part of the everglades growing over 9 feet on rich dark peat soils. Today, much of that land has been drained and cleared to grow sugar cane. Saw grass is also found in the southern and central regions of the glades

Hydroperiod

seasonal patterns of precipitation sets the hydroperiod. Sheet flow of water from june to october. Hurricanes bring in massive amounts of water. Humans have altered the Hydroperiod

Water table fluctuation

High in the rainy season low in the dry. Depends on the topography and is affected by alligator activities

Freshwater slough

deep marsh with avergage depth of 30cm and max around 1 meter. Sloughs are the main path of moving water in the glades. Hydroperiod almost all year round making it a ideal habitat for aquatic plants. Calcareous periphytpn (algal mat) and other aquatic plants sit at the bottom of the food web. wading birds and alligators are the top predators.

Pinelands

Sand, nutrient poor, dry and fire prone

Pineland animals

Dry land reptiles: geckos, skinks, gopher tortoise - burrows increase the diversity of soil nutrient availability, plants and animals

Hardwoods Hammock

habitat on higher elevations making it a dry habitat (like the pinelands).

Hardwood trees and shrubs

Wild coffee, gumbo-limbo tree, royal palm, strangler fig, mahogany. There are vines and few herbs on the ground and epiphytes

Moat around hammock

eroded limestone, water depth of 1-2 feet, used to be year round

Wading birds

16 dif species in glades: great egret, snowy egret, tricolored heron, wood stork. They are piscivorous birds (eats fish). Long legs allow them to wade in shallow water and stab their prey with their long beaks. Indicator species affected by the health of the entire ecosystem.

Wading birds pattern of energy

Summer rainy season - energy collected by plant primary production and consumer growth, fall - energy concentation with high prey density, winter/spring - dry season with spatial variation of wet places

Wading birds pattern of behavior

Summer - non breeding many flying north and leaving the glades, fall - energy aquiring, winter and spring - nesting phase (3-4 months)

Wading birds migration

Tremendous increasee in numbers of wading birds that congregate each year during the dry season nov - may. between 50,000 and 100,000 birds collect attracted by the feeding conditions created by the drying marshes

The wood stork

Used to be abundant but the changes in flooding and drying patterns have decreased the population by 90 percent

Dale Gawlik prey availability hypothesis in the everglades

Do the wading birds compete for food? he hypothesized several factors that would affect prey availability: water depth, prey density and species characteristics of the wading birds

Dale gawliks experiment

He constructed 12 ponds with different water depths and prey densities. Used 8 wading bird species the smaller bird group with wading maximum of 19cm (white ibis, glossy ibis, snowy egret, tricolored heron, little blue heron). The larger bird group with a maximum if 28 cm (great egret, great blue heron and wood stork. Bird density was species-specific - white ibis peaked earlier then left while great egret peaked later. Fish density was highest in the deep pool and depleted in the shallow. He found that water depth effect is more complex than leg length - “searchers” (white ibis and wood storks) vs “exploiters” (great blue heron and great egret) wtf

Mangrove swamps

The freshwater runoff upstream provides nutrients and tidal flushing moves the nutrients around. the mangroves provide habitats fro shrimp and other fish species and are a feeding ground for wading birds.

Aligators

females lay 40-60 eggs in a nest. They attend to the babys for 1-2 years and they need both wet and dry habitat. They are ecosystem modifiers because they create ponds called alligator holes that are a refuge for water and animals in the winter.

Human alteration of the everglades

Drainage of sawgrass marsh (south of lake okeechobee) - diverting water to the Atlantic ocean and gulf of mexico, marsh conversion to agricultural land, loss of peat (rich organic soil), water table drop, saltwater intrusion. 50 percent of the historical everglades is gone

Creation of the water conservation areas in the ridge and slough zone

Wcas are ponded compartments like water storage reservoir, loss of tree islands from the landscape, eutrophication due to high P loads

Areas with too much water and ecological consewuence

Water conservation areas. Loss of tree islands, P pollution, cattail invasion, loss of calcareous periphyton mats, loss of biodiversity, reduction of prey available for wading birds

Areas with too little water and ecological consequence

Everglades National Park and coastal mangrove swamps. Consequences: shorter hydroperiod, loss of algae mats, loss of biodiversity, reduction of prey availability for wading birds, impact on alligators, salt water intrusion

Invasive Melaleuca

Native to Australia and Malaysia it was introduced to Flordia in 1906 as commercial timber. it was also planted to dry off the Everglades to decrease mosquito populations. Melaleuca trees go quickly 3-6 feet a year in wet pine flatwoods, marshes, and swamps. It’s rapidly displacing native cypress and sawgrass in the glades. It can flower five times a year and seeds can remain viable for ten years. A single tree can store 2-20 million seeds. They form dense strands that displace native plants. They alos pose a serious fire hazard bc of the oils in the leaves.

Consequences of cattail invasion

Cattail is a native species so how did it become invasive? The increase in phosphorus loads in a naturally limited ecosystem. The consequences of invasion - high primary production, low plant biodiversity and low secondary and tertiary production, high decomposition, and altered food web

What is a wetland

An ecosystem that arises when inundation by water produces soils dominated by anaerobic processes and forces the biota, particularly rooted plants, to exhibit adaptation to tolerate flooding.

Bog

Dominated by sphagnum moss, sedges, ericaceous shrubs that rooted in deep peat

Fen

Dominaed by sedges and grasses rooted in shallow peat with considerable water movement. Peat forming wet lands that recive nutrients from sources other then precipitation

Wetland soils

A shortage of oxygen, accumilation of toxic gases H2S and CH4, atypical conc of some ions

Wetlands under global change

Accelerated soil respiration under warming and co2 release. Accelerates release of ch4 and N2O

Cypress heads

“island”, depression in limestone, wet year round

Bald cypress

roots withstand water, shed leaves yields acid, fire protecion

Kissimmee river

flows from northern florida into Lake Okeechobee, 100 miles straightened to 50. reduced natural filtration, contaminated water increased eutrophication, reduced water storage, delivered water faster to lake, needed diversion canals to reduce flooding