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Biomes 1 Biomes The objective of this set of lectures is to familiarize you with the major vegetation communities on Earth. Biomes are somewhat arbitrary, descriptive classifications, rather than quantitative or objective categories. The lines between biomes are often vague. Even so, this system is generally useful for understanding the diversity, and ecology, of the Earth’s vegetation. Figure 23.1 Paleartic Neartic Oceania Oceania IndoMalay Neotropic Afrotropic Australasia Antartic Tropical and subtropical moist broadleaf forests Temperate grasslands, savannas, and shrublands Tropical and subtropical dry broadleaf forests Flooded grasslands and savannas Tropical and subtropical coniferous forests Montane grasslands and shrublands Temperate broadleaf and mixed forests Tundra Temperate coniferous forests Mediterranean forests, woodlands, and scrub Boreal forests/taiga Deserts and xeric shrublands Tropical and subtropical grasslands, savannas, and shrublands Mangroves Precipitation and temperature are the two most important controls on biome formation and stability. The distribution of biomes across the planet depends, largely, on those factors. So… although we are going to give names to some biomes- you can imagine that the biome itself (and boundaries between biomes) are variable across temperature and precip gradients. You need to understand this concept, and have a general idea of how biomes abut, and vary, across these gradients. 18.2 The distribution of biomes is determined by climate General Classification Scheme -Tundra -Taiga/Boreal Forest -Mixed Conifer Forest -Deciduous Forest -Savanna -Shrublands -Grasslands -Desert -Subtropical & Tropical Tundra •Climate •Soils/Setting •Dominant Vegetation •Characteristic Animals •Misc Tundra Tundra is the characteristic ecosystem in extremely cold climates. Plants are mostly very low in stature. Animals often migratory. Soils are often deep with frozen layers of organic matter. Permafrost is a characteristic feature of the soils Tundra Soggy soils in summer, pock marked, low herbaceous vegetation. Willow and alder are common/typical Tundra species in tundra areas. The particular species found in tundra are “crawling”, and extremely tolerant of cold. They are easily overcome/outshaded by other species (spruce and fir, in particular) if conditions improve. Alder is a nitrogen fixing plant, and has an interesting “successional” relationship with other species. In the winter, (and in extremely cold areas) tundra can be expansive snow and ice fields. http://www.youtube.com/watch?v=3XbJpevfNAs Willow: Salix sp. Alder: Alnus sp. Caribou (Rangifer tarandus) - herds, migratory http://www.youtube.com/watch?v=5AYHvkR-0Qo Polar bear (Ursus meritimus) Weight: 1500 lbs Height: ~9 feet Polar bears hunt on ice sheets, ripping seals from the ice like sardines from a can. Tundra http://www.youtube.com/watch?v=DxVMnJXWvdM 18.2 The distribution of biomes is determined by climate General Classification Scheme -Tundra -Taiga/Boreal Forest -Mixed Conifer Forest -Deciduous Forest -Savanna -Shrublands -Grasslands -Desert -Subtropical & Tropical Taiga aka Boreal Forest aka Spruce-Fir Forest Taiga aka Boreal Forest aka Spruce-Fir Forest Taiga/Boreal Forest Boreal forest are circumpolar, taking up vast areas of North America, Europe, Siberia, etc. They are areas that are cold enough that deciduous species are at a competitive disadvantage. What does that mean? Soils are covered by a deep organic layer of fallen needles, which decompose VERY slowly. These forests are dominated by two genera of tree… Taiga/Boreal Forest Fir: Abies Spruce: Picea Moose (Alces alces) Height: 6-7 feet Weight: 1500 lbs Grey Wolf (Canis lupus) ~100 lbs This critter is badly misunderstood. There are very few records of wolves attacking people. It only happens if the wolf has been (a) conditioned by idiots at parks who feed wolves their Big Macs or (b) something odd is happening- the animal is injured and starving, etc. It is 1 billion%* more likely that you will be bitten by Aunt Edna’s “Pom Pom” than by a wolf, even if you lived in an area where wolves were present. * An approximation Wolves are very important to ecosystem structure. We will focus on this later in the semester. By the way, wolves do not blow down pighouses, hide in grammas cloths, and (despite photographic evidence- to the right) they most likely did not nurse the founders of Rome, i.e., Romulus and Remus. 18.2 The distribution of biomes is determined by climate General Classification Scheme -Tundra -Taiga/Boreal Forest -Mixed Conifer Forest -Deciduous Forest -Savanna -Shrublands -Grasslands -Desert -Subtropical & Tropical -Mixed Conifer Forest Mountain gradients. Rain shadows. Climate. Ponderosa pine (Pinus ponderosa). Enormous size: 200 ft tall Fire Ecology Ecological importance http://www.youtube.com/watch?v=mjdRgBAY278 Moist Conifer Forests of the Pacific Northwest Coastal Redwood (Sequoia sempervirens) ~1500 years 380 feet tall Tallest living thing on Earth Coastal Redwood (Sequoia sempervirens) Coastal Redwood (Sequoia sempervirens) Captures and imbibes water from fog using foliage. Translocates this water down the stem. Not sure how…. Douglas-fir Pseudotsuga menziesii 390 feet (one was taller than redwood, but has since been lost) ~1500 years Douglas-fir Pseudotsuga menziesii Some of you have “real Christmas trees” every year, and you probably buy the tree from Lowes of something- if so, the tree has a good possibility of being Douglas fir (Pseudotsuga menziesii). You might also have this tree planted in your yard. Why would someone plant a tree from Washington State in your yard? I have no clue Douglas-fir is neither a Douglas, or a fir. It is a tree that is relatively closely related to firs which are the genus ________. Douglas-fir is of enormous ecological and economic importance. It is one of the most widespread species in North America, with varieties ranging basically across the whole “conifer forest” area. It is extremely valuable for lumber. Cougar; mountain lion; catamount; panther = Puma concolor - top predator. Avoids humans, but rare occasions of people being stalked and killed. -Length ~ 8 feet (including tail), Weight ~200lbs. -Can run ~ 55 mph, vertical leap = 18ft Issues of Conservation 18.2 The distribution of biomes is determined by climate General Classification Scheme -Tundra -Taiga/Boreal Forest -Mixed Conifer Forest -Deciduous Forest -Savanna -Shrublands -Grasslands -Desert -Subtropical & Tropical Deciduous Forest Deciduous Forest Regions American beech: Fagus grandifolia Oaks Family: Fagaceae Genus: Quercus Maples Family: Aceraceae Genus: Acer Specifically: Red maple Sugar maple Live oak Longleaf pine- a particular example of fire adaptation Coyote (Canis latrans) Length (not counting tail): 2.5 feet Weight: 20-45 lbs Attacks on humans extremely rare- Aunt Ednas “pom pom” much more likely to hurt you. Might kill your cat, though. And they do kill small mammals mice, rabbits, raccoons- also snakes, deer, and they eat carrion. http://www.youtube.com/watch?v=97I-IDIKVSU&feature=related White-tailed Deer (Odocoileus virginianus) Shoulder height: 40 inches or so Weight: 100-300 lbs, largest known = 500 lbs Populations of deer in eastern North America are growing explosively. Why? (a) Unchecked by predators, and (b) living in environments that are highly conducive to population growth, they have become a major problem. http://www.insurancejournal.com/news/national/2012/10/24/267786.htm blue jay (Cyanocitta cristata ) Corvidae Lin northern cardinal (Cardinalis cardinalis) Cardinalidae Lin American robin (Turdus migratorius) Turdidae Lin Biomes 1