Chapter 2 Land Announcements? IN AFS tonight  5 pm, CL 167 Nick Haunert, Eagle Creek Reservoir Fish Molles: Ecology 2 nd Ed.

Objectives: Describe climate based on climate diagrams Explain how climate controls geographic distribution of biomes based on:  Temperature extremes  Temperature and precipitation seasonality Match biomes to their geographic locations Describe soil characteristics that influence plant species distribution within biomes

Molles: Ecology 2 nd Ed. Chapter Concepts Uneven heating of earth’s surface by sun and tilt of earth’s axis, combine to produce predictable latitudinal variation in climate

Molles: Ecology 2 nd Ed. Chapter Concepts Geographic distribution of terrestrial biomes closely corresponds to variations in climate, especially temperature and precipitation

Molles: Ecology 2 nd Ed. Introduction Janzen studied tropical dry forests in Costa Rica for restoration efforts  Guanacaste tree (E. cyclocarpum)

Molles: Ecology 2 nd Ed. Introduction Janzen studied tropical dry forests in Costa Rica for restoration efforts.  Guanacaste tree (E. cyclocarpum)  No current dependable dispersers; trees produce massive numbers of fruits

Molles: Ecology 2 nd Ed. Introduction Janzen studied tropical dry forests in Costa Rica for restoration efforts.  Guanacaste tree (E. cyclocarpum)  No current dependable dispersers; trees produce massive numbers of fruits.  Last native dispersers extinct 10,000 years ago (sloths, camels). – Cattle and horses (exotics) dispersers.

Molles: Ecology 2 nd Ed. Natural history info is important!

Molles: Ecology 2 nd Ed. Soil Factors that Determine Species Distributions

Molles: Ecology 2 nd Ed. Mineral composition Nutrient availability Toxic substances (metals) pH Solubility of nutrients / toxic metals

Molles: Ecology 2 nd Ed. Soil Texture Relative amounts of gravel, sand, silt, clay  Silt & Clay  Water retention  Nutrient retention and availability  Gravel & Sand  Aeration (oxygen for roots) Organic matter has beneficial influence on water/nutrient availability AND aeration

Molles: Ecology 2 nd Ed. Texture, Aeration, and Soil Water

Molles: Ecology 2 nd Ed.

Soil : Foundation of Terrestrial Biomes Soil: Complex mixture of living and non-living material.  Classification based on vertical layering (soil horizons).  O Horizon  A Horizon  B Horizon  C Horizon

Molles: Ecology 2 nd Ed. Soil Horizons O: Organic Layer freshly fallen organic material – most superficial layer. Fig. 2.3

Molles: Ecology 2 nd Ed. Soil Horizons O: Organic Layer freshly fallen organic material – most superficial layer. A: Mixture of minerals, clay, silt and sand. Fig. 2.3

Molles: Ecology 2 nd Ed. Soil Horizons O: Organic Layer freshly fallen organic material – most superficial layer. A: Mixture of minerals, clay, silt and sand. B: Clay, humus, and other materials leached from A horizon – often contains plant roots. Fig. 2.3

Molles: Ecology 2 nd Ed. Soil Horizons O: Organic Layer freshly fallen organic material – most superficial layer. A: Mixture of minerals, clay, silt and sand. B: Clay, humus, and other materials leached from A horizon – often contains plant roots. C: Weathered parent material. Soil profile = snapshot of soil structure in constant state of flux. Soil profile = snapshot of soil structure in constant state of flux. Fig. 2.3

Molles: Ecology 2 nd Ed.

Drainage Water retention & Aeration  Topography Run-off  Flat vs. Sloped  Upper vs. Lower Slope  Convex vs. Concave  Impervious soil layers  Infiltration  Soil texture

Molles: Ecology 2 nd Ed. Soils influence local distribution of plants Texture: water, nutrients Parent rock: pH, nutrients, toxic metals Organics: water, nutrients pH: nutrient availability, solubility of metals Drainage: aeration of roots, solubility of metals Plants add organics, influence weathering

Molles: Ecology 2 nd Ed. Climate Temperature and precipitation regime that is typical for a specific location or region:  Average temp. and precipitation  Temp. extremes (especially minimum)  Seasonality of temp. and /or precipitation

Molles: Ecology 2 nd Ed. Factors That Control Regional Climate Latitude (affects solar radiation) Direction of prevailing winds  From ocean or from land (moist vs. dry)  From tropical or polar (warm vs. cold)  Rain shadow of mountains Proximity to large water bodies Elevation

Molles: Ecology 2 nd Ed. Climate variability Large-scale patterns

Molles: Ecology 2 nd Ed. Fig 2.5 Large Scale Patterns of Climatic Variation: Temp., Atmospheric Circulation, and Precip. Spherical shape, tilt of earth’s axis:  uneven heating of earth’s surface.

Molles: Ecology 2 nd Ed. Drives air circulation patterns and consequently precipitation patterns.  Warm, moist air rises.  Cools, Condenses, and falls as rain.  Cooler, dry air falls back to surface. Fig 2.5

Molles: Ecology 2 nd Ed. Fig 2.5 Rainforests at equator. Major Deserts at 30 o N and S.

Molles: Ecology 2 nd Ed. Fig 2.5

Molles: Ecology 2 nd Ed. Temp., Atmospheric Circulation, and Precip. Coriolis Effect =  winds clockwise in N hemisphere; counterclockwise in S hemisphere. Fig 2.5

Molles: Ecology 2 nd Ed. Climate Diagrams Summarize various env. variables for area.  Allows quick comparison between areas for vegetative growth predictions. Fig 2.7

Molles: Ecology 2 nd Ed. Fig 2.7

Molles: Ecology 2 nd Ed. Fig 2.8

Molles: Ecology 2 nd Ed. Fig 2.8

Molles: Ecology 2 nd Ed. Terrestrial Biomes Biomes: distinguished by plants – associated with particular climates

Molles: Ecology 2 nd Ed. Biome A major geographic region characterized by a distinctive assemblage of life forms.  Defined by dominant plant life forms on land.  Defined by dominant plants or animals in sea. Terrestrial biomes generally the result of large-scale climate patterns.

Molles: Ecology 2 nd Ed. Natural History and Geography of Biomes Main factors determining biomes are:  Temperature and Precipitation

Molles: Ecology 2 nd Ed.

Tropical Rainforests Within 10 o lat. of equator Little temp variation Annual rainfall 2,000 – 4,000 mm Annual rainfall 2,000 – 4,000 mm  Heavy rainfall leaches soil nutrients Organisms add vertical dimension Organisms add vertical dimension Staple foods + medicines for human pop’s – increasingly exploited Staple foods + medicines for human pop’s – increasingly exploited

Molles: Ecology 2 nd Ed. Fig 2.10

Molles: Ecology 2 nd Ed. Tropical Dry Forest 10 o – 25 o latitude 10 o – 25 o latitude More seasonal than tropical rainforest More seasonal than tropical rainforest Soils richer in nutrients, but erosion Soils richer in nutrients, but erosion Shares many animal and plant spp. w/ tropical rainforests Shares many animal and plant spp. w/ tropical rainforests Heavily settled by humans – extensive clearing for ag Heavily settled by humans – extensive clearing for ag

Molles: Ecology 2 nd Ed. Fig 2.13

Molles: Ecology 2 nd Ed. Fig 2.14

Molles: Ecology 2 nd Ed. Tropical Savanna N / S of Dry Forests N / S of Dry Forests Alternate between wet / dry seasons Alternate between wet / dry seasons  Drought w/ dry season = dry conditions; lightning-caused wildfires. Soils low water permeability. Soils low water permeability.  Saturated soils keeps trees out. Increasing pressure to produce livestock. Increasing pressure to produce livestock.

Molles: Ecology 2 nd Ed. Fig 2.16

Molles: Ecology 2 nd Ed. Desert 30 o N and 30 o S 30 o N and 30 o S ~ 20% of earth’s land surface ~ 20% of earth’s land surface Water loss > precip. most of year Water loss > precip. most of year Soil usually extremely low in organics Soil usually extremely low in organics Plant cover sparse to absent Plant cover sparse to absent Animal abundance low; biodiversity may be relatively high Animal abundance low; biodiversity may be relatively high  Strong behavioral adaptations Human intrusion increasing. Human intrusion increasing.

Molles: Ecology 2 nd Ed. Fig 2.19

Molles: Ecology 2 nd Ed. Warm Desert

Molles: Ecology 2 nd Ed. Cold Desert

Molles: Ecology 2 nd Ed. Temperate Woodland and Shrubland All continents except Antarctica All continents except Antarctica Cool and moist in fall, winter, and spring, can be hot / dry in summer Cool and moist in fall, winter, and spring, can be hot / dry in summer Fragile soils w/ moderate fertility Fragile soils w/ moderate fertility Trees and shrubs typically evergreen Trees and shrubs typically evergreen Fire-resistant plants due to fire regime Fire-resistant plants due to fire regime Long history of human intrusion Long history of human intrusion

Molles: Ecology 2 nd Ed. Fig 2.22

Molles: Ecology 2 nd Ed. Temperate Grassland Extremely widespread Extremely widespread Annual rainfall 300 – 1,000 mm Annual rainfall 300 – 1,000 mm Periodic droughts Periodic droughts Soils extremely nutrient rich / deep Soils extremely nutrient rich / deep Dominated by herbaceous vegetation Dominated by herbaceous vegetation Large roaming ungulates Large roaming ungulates  Bison vs. cattle

Molles: Ecology 2 nd Ed. Fig 2.25

Molles: Ecology 2 nd Ed. Tall Grass Prairie

Molles: Ecology 2 nd Ed. Mixed Grass Prairie

Molles: Ecology 2 nd Ed. Short Grass Prairie

Molles: Ecology 2 nd Ed. Why No Trees In Chaparral or Grasslands ??? Drought-free growing season too short Not enough time to accumulate energy to produce large woody stem. Seasonal precipitation causes Fire Climate Frequent fires more likely to kill trees than to kill shrubs and grasses.

Molles: Ecology 2 nd Ed.

Temperate Forest 40 o and 50 o latitude 40 o and 50 o latitude Rainfall averages 650 – 3,000 mm Rainfall averages 650 – 3,000 mm Fertile soils Fertile soils  Long growing seasons = deciduous plants  Short growing seasons = conifers Biomass production can be very high Biomass production can be very high Many major human population centers Many major human population centers

Molles: Ecology 2 nd Ed. Fig 2.28

Molles: Ecology 2 nd Ed. Boreal Forest (Taiga) N. hemisphere N. hemisphere  11% of earth’s land Thin, acidic soils low in fertility Thin, acidic soils low in fertility Dominated by evergreen conifers Dominated by evergreen conifers High animal density High animal density Historically, low levels of human intrusion Historically, low levels of human intrusion

Molles: Ecology 2 nd Ed.

Fig 2.31

Molles: Ecology 2 nd Ed. Tundra Most of land N of Arctic Circle Most of land N of Arctic Circle  Cool + dry w/ short summers  mm precip.  Low decomposition rates  Substantial numbers of native mammals  Human intrusion historically low, increasing as resources become scarce

Molles: Ecology 2 nd Ed.

Fig 2.34

Molles: Ecology 2 nd Ed. Biomes of North America

Molles: Ecology 2 nd Ed. Summary Uneven heating of earth’s surface drives global precipitation patterns. Distribution of terrestrial biomes corresponds to variation in climate.  Temperature  Precipitation Within a single biome (climate region), soil characteristics influence the distribution of plant species, which in turn influences the distribution of other species.

Molles: Ecology 2 nd Ed.