* Rainforest p2-3 ·Location: Central America, Caribbean islands ·Features: Vast number of densely spaced trees and enormous diversity of species. General lack of seasonality. Precipitation about 80-160 in (200-400 cm) or more in North America Mean average temperature is 70-80° F (22-27° C) for most of the region. Frost and freezing temperatures restricted to tropical mountains. High humidity, narrow temperature fluctuation, uniform day-length; growing season up to 365 days a year. Soils are geologically old and therefore generally poor in mineral nutrients. Fires common during dry season, mostly slow burning and not hot ·Vegetation: Multiple layers in the canopy; significant biomass. Lianas (woody vines) and epiphytes (plants that live on other plants) are common, many can be parasitic or semi-parasitic. Usually large smooth leaves with drip points to prevent water from accumulating on the blade. Extreme diverse array of species in small area
·Animals: Numerous species of mammals of diversity types: monkey, tapir, panther, sloth, etc. Many unique kinds of birds (e.g., parrots), home of numerous migratory song birds and water fowl. Incredible numbers of insects; a single tree can harbor some 30,000 different species. ·Exploitation: Cutting of forest to create large expanses of grazing land rapidly depleting tropical forests resulting in soil depletion, erosion and changes in local climates. It is estimated that approximate 80 acres a minute of rain forest are disappearing, roughly an area the size of the state of Colorado yearly. Mining and logging (for lumber and pulp) resulting in forest destruction and pollution, silting, and other water problems. Introduction of exotic species often resulting in loss of native species. It is estimated that nearly 50 species go extinct each day in the tropics, largely due to human pressures.
* Temperate Deciduous Forest p4-5 ·Location: Eastern portion of North America. ·Features: Composed of numerous, well-defined vegetation associations dominated by deciduous trees and shrubs. Variable climate, warmer and wetter in the south Precipitation 30-60 in (75-150 cm) annually, mostly as rain Growing season of 120 (Canada) to 250 (Florida) days. Temperature extremes can be significant: -20 to -40° F to 100 to 110° F. Hurricanes and freezing rain can cause considerable physical damage to the vegetation. Soils more acid and fertile in north. Composed primarily of hardwoods with a mixture of conifers. ·Vegetation: Variety of hardwoods: Quercus (oak), Acer (maple), Fagus (beech), Tilia (basswood), Castanea (chestnut), and Carya (hickory). Tulip poplar (Liriodendron) also common. Scattered conifers mostly pines. Numerous shrubs, many of the heath family (e.g., Rhododendron (left), Kalmia; blueberries (Vaccinium) also common. Numerous grasses and wild flowers throughout the growing season.
·Animals: Mammals: Deer; moose and bear were common; historically buffalo in the area. Raccoon and opossum common, so are skunks. Predators: Fox common; bobcat or lynx rare; wolves and mountain lion extirpated. Birds: Resident and migratory; numerous song birds and waterfowl. ·Exploitation: No undisturbed forest present today due to extensive logging. Introduction of Chinese chestnut into New York Zoological Garden resulted in a fungal disease that destroyed the American chestnut. Clear-cutting of forest for farming coupled with introduction of exotic weed species has fundamentally altered the flora. Soil erosion and depletion has made it difficult for some species to re-invade disturbed sites. Erosion has resulted in silting and deposition in wetlands; some 90% of the wetlands in Maryland have been destroyed. Numerous species of plants and animals have gone extinct or have been extirpated over significant portions of their native range.
*Taiga p6-7 ·Location: Circumpolar in northern hemisphere. Alaska and Canada to northeastern and Great Lakes region of the United States. Area often characterized as "boreal forest", "northern coniferous forest" or "Cold Climate Forest". ·Features: Forest dominated by densely arranged dark evergreen conifers; an effective "carbon sink". Little moisture (17-20 in or 40-50 cm) mostly as summer rains. Freezing temperature, extreme cold (-100° F are not uncommon). The temperature rarely exceeds 85° F in the summer. The growing season is 90 to 120 days per year. Snow is common. Shallow soils, wet, deep permafrost; nutrient poor. Fire is an occasional factor. ·Vegetation: Northern edge defined by a timberline Trees include both softwoods (conifers) and hardwoods (flowering plants) Other plants: Shrubs include willows and members of the heath family (Ericaceae) but not Erica the true heath. Graminoids (mainly grasses), lichens and bryophytes (Sphagnum). Succession: Shallow ponds or lakes to peat bogs to graminoids to shrubs to trees. About 1800 species of vascular plants
·Animals: Large mammals: Elk, caribou, deer, bear (brown, grizzly). Predators: Wolves, bear, lynx, wolverine, fox. Birds: Migratory and some resident birds, especially song birds. Insects: black flies, midges, gnats and mosquitoes ·Exploitation: Hunting is leading to a loss of many species, especially fur-bearing animals. Mineral exploitation resulting in habitat loss and pollution. Fire: mainly natural and part of the succession process. Lumbering: may be a threat in the near future. Productivity limited by cold and varies greatly throughout the region
* Savanna p8-9 ·Similar to Grassland and Tropics. ·Large open areas of tropical graminoids and scattered low trees and shrubs. Formed by combination of dry, nutrient poor soils with possibly some influences by climate and human activities, the latter two not well understood. Probably maintained by grazing animals (to Early Holocene) and fire. Savannas in Central America and parts of South America, more common in Africa. Considerable diversity and threat.
* Grassland p10-11 ·Location: Major grasslands are widely scattered, covering nearly a quarter of the landed surface: North America ("prairie") Russia ("steppes"), South Africa ("veld"), Argentina ("pampas"). ·Several grasslands are found in North America: Great Plains Palouse Prairie California grasslands ·Features: Dominant plants are members of the grass family (Poaceae), several genera and species common but usually with one or two dominate. Most grasses are rhizomatous (possessing rhizomes) and are wind pollinated. Moderate temperature but notable extremes: -20° F to 110° F common, and even colder temperatures in the north. Variable precipitation: 6-40 in (15-100 cm). Soils generally fertile, deep and rich; variable Growing season of 120-200 days. Generally flat to rolling topography cut by stream drainages where there is a riparian or river-bank habitat. Scattered rain and lightening common in summer months ("convection storms") with more general rains and snows in winter months. Fire a major factor in maintaining biome.
·Vegetation: Mixed grasses and shrub, especially sagebrush (Artemisia tridentata). ·Animals: Deer and antelope today; buffalo, camels, horses and mammoth along with an array of predators such as great cats and wolves into early Holocene. ·History: Always small but now invaded by desert species. ·Exploitation: Dry-land farming and grazing.
* Chaparral p12-13 ·Location: Coastal southern California and northern Baja California, Mexico. Widely scattered elsewhere in the world: southern Europe and northern Africa, Cape Region of southern Africa. ·Features: Dominated by microphyllous (small), sclerophyllous (e.g. leathery), xerophytic (dry) evergreen shrubs and a mixture of low conifers and hardwood trees. Climate: Cool and wet in winter; hot and dry otherwise. Precipitation as rain in late Nov to early Apr, 14-29 in (35-75 cm); falls as rain or rarely as snow. Seasonally warm in winter, hot in summer, frost infrequent, can exceed 110° F. Slope and exposure critical; moist north-facing, dry south-facing; slopes usually steep. Hot winds and fire frequently occur in late fall at end of dry season. Generally poor soils, shallow and rocky. Fire climax community. ·Vegetation: Dominant shrubs are chamise (Adenostoma fasciculatum), California buckwheat (Eriogonum fasciculatum), various species of manzanita (Arctostaphylos), and (at higher elevations) species of ceanothus (Ceanothus). Dominant trees are oaks (Quercus) and pines (Pinus). Many endemic species of wildflowers; flowers most common from March to June. Many species have volatile oils in the leaves meaning that they burn rapidly. Many species specially adapted to repeated burning (e.g., root crowns ("lignotuber") from which new shrubs can grow; cones of pines ("cone serotiny") that require high heat to open.
·Animals: Diversity of birds, especially ground birds, deer and small mammals. Many species of both plants and animals are narrowly endemic. ·Exploitation: Intensively grazed has resulted in some extinction. Fire suppression is resulting in larger and hotter fires that kill plants otherwise adapted to fire. Population growth coupled with urban expansion is fragmenting the vegetation
* Desert p14-15 ·Three major types: Cold Deserts: Arid regions where precipitation falls sparingly principally as snow and permafrost is not a factor; vegetation is primarily xerophytic and sclerophyllous shrubs with scattered, low trees. Warm Deserts: Arid regions where precipitation falls seasonally principally as rain, some snow and frost each year; vegetation is xerophytic and sclerophyllous shrubs with scattered trees or arborescent cacti. Hot Deserts: Arid regions with little or no annual precipitation, usually rain, no snow or frost; vegetation sparse and scattered, often limited to moist areas, or even lacking entirely except following periods of adequate regional moisture. Not found in North America COLD DESERT: ·Features: Precipitation falls primarily as winter snow. Summer showers can be heavy and cause local "flash floods" in many areas. Temperature cool (rarely below -15° F) in winter and warm in summer (rarely above 100° F). Soils variable, sandy to rocky, mostly volcanic or limestone in Great Basin, mostly sandstone in Canyonlands. Valley bottoms mostly above 4000 ft (1220 m).
WARM DESERT: ·Features: ·Mojave Desert Low, mostly treeless mountain ranges and broad, open valley bottoms. Extremes in elevation (-282 ft below sea level; near by Panamint Peak is 11,049 ft or -86 m to 3270 m) and temperatures (Death Valley recorded the hottest temperature in the United States at over 126° F). Precipitation mostly Dec through Mar; 2-5 in (5-12.5 cm) annually; results in winter annuals - plants that flower and fruit in about 8 weeks (see right). Summer convection storms mean local flash flooding and summer annuals. Great diversity of annual species resulting in numerous endemics. ·Exploitation: Extensive, long-term overgrazing has resulting in many introduced weeds, most notably the Old World tumbleweed (Salsola spp) now found throughout the West. Some mining and limited logging especially in mountains. Off-road vehicle (ORV) damage significantly altering portions of the warm deserts.
* Tundra p16-17 ·Location: Northernmost and circumpolar in northern hemisphere. Northern Alaska and Canada, all of Hudson Bay in east. ·Features: Dry: (6-14 in or 15-35 cm) as summer and fall cold rains. Cold: Freezing temperature can occur any day of the year and temperatures rarely exceed 15° C even during the warmest of months. The growing season varies from 60 to 100 days a year. Soils: Wet, shallow, often frozen or with permafrost; shallow lakes, known as polygons One physical feature of the region (both here and in the montane biome) is the force of glaciation caused by a glacier. Glaciers are particularly impressive and massive in Antarctica. The consequences of past glaciation may be seen in the Sierra Nevada of California ·Vegetation: Low shrubs and herbs, mostly graminoids - grass-like plants. Some 700 species. Defined by a distinct tree line
·Animals: Migratory birds, especially water birds. Predators: wolves, arctic fox, weasels, owls, etc. Large mammals: bear, caribou (New World) or rain deer (Old World), musk oxen, polar bear and Dall sheep. Small mammals: voles, lemmings Insects: Black flies, mosquitoes, gnats Low diversity and productivity ·Exploitation: Habitat destruction due to exploitation of natural resources. This "frozen" or "polar desert" requires centuries to recover. Possible impact from global warming which is having a greater impact in the tundra than elsewhere. Threat of pollution.