Ecosystems and Climate Controls Lecture PDF

Communities, Ecosystems & Climate  Goals of Today’s Lecture 1. To understand to ecological concepts of community, ecosystem, and biogeochemical cycles 2. To review global patterns of climate and physical geographic controls on climate 3. To look at patterns of vegetation (biomes) as c...

Communities, Ecosystems & Climate  Goals of Today’s Lecture 1. To understand to ecological concepts of community, ecosystem, and biogeochemical cycles 2. To review global patterns of climate and physical geographic controls on climate 3. To look at patterns of vegetation (biomes) as controlled by latitude, altitude and other climate controls  Earth’s “Spheres” Abiotic (non-living) and biotic (living) spheres Three abiotic spheres: atmosphere, hydrosphere, lithosphere Biotic sphere: biosphere  Systems Concept System: a set of objects and/or attributes together with their relationships, operating as a complex whole 1. Isolated system: has boundaries that are closed to the import and export of matter and energy 2. Closed system: has boundaries that are closed to the import and export of matter, but that allow the exchange of energy 3. Open system: has boundaries that allow free exchange of matter and energy with the surroundings  Communities & Ecosystems Organisms don’t live in isolation – Interactions; competition for resources – Specializations in lifeways – Certain foods, microclimates – Co-dependencies (predator-prey, parasite-host, etc.) Result is a community – Assemblage of organisms Interact with abiotic environment in an ecosystem – Distribution patterns related to climate, etc.  The Community Community: assemblage of species in an area – May be broadly used (total assemblage of living species), or more limited (bird community, plant community, etc.) Plants and animals together – Relationships (plant / herbivore, etc.) – Often associated with a specific habitat Plant communities – The basis for biological mapping and habitat definitions – Fix energy from Sun, take up water and minerals from soil – Species with similar optima and limits will occur together  The Ecosystem Organisms & physical / chemical environment – Rock, soil, water, atmosphere – A complex, interactive system – Exist at various levels (global to local) – Concerned with processes that link organisms Fundamental concepts: energy flow and nutrient cycling Ecosystems  Ecosystem Components Biotic (living) Components Autotrophs (self feeders): Producers → make organic matter from inorganic substances using either light or chemical energy Phototrophs: get energy from light through photosynthesis (green plants, most algae, and some bacteria) Chemotrophs: get energy from inorganic substances by chemical processes (most bacteria and some algae)  Ecosystem Components Biotic (living) Components Heterotrophs (other feeders): Consumers → feed upon organic matter produced by autotrophs. Holozoic organisms: eat by mouth; (herbivores, carnivores, and scavengers) Saprophytes: feed on soluble organic compounds from dead plants and animals (fungi and bacteria) Parasites: rely on other living organisms for food  Ecosystem Components Abiotic (non-living) Components Light energy Inorganic chemical elements (such as iron, carbon, nitrogen, and oxygen) or compounds (such as water and carbon dioxide). Organic compounds such as proteins, carbohydrates, and lipids (fats) that link the biotic and abiotic. Air, water, and substrate conditions, which are generally grouped together as the physical factors or the physical environment.  Trophic Levels Trophic levels and biomass pyramid. Decrease in numbers and/or biomass with each successive trophic level. Energy Flows  Nutrient Cycling Nutrients: chemical elements essential for growth / maintenance of organisms Ecosystem Linkages  Biotic Assemblages Useful to consider interactions between biotic and abiotic parts of an ecosystem Interested in roles that species play within the ecosystem Different parts of world have different species, but may be functionally very similar – E.g., Northern Iran vs Mojave Desert Similar climatic and soil conditions; similar overall appearance & structure Different species; ecological equivalents Consider general form and lifestyle of vegetation – Can compare vegetation of similar climatic locations globally Vegetation Patterns  Biomes Biome: a large, stable community of plants and animals whose boundaries are closely linked to climate – Ideally defined by mature, natural vegetation – Most of Earth’s biomes have been affected by human activities  Global Patterns of Climate Climate: range of weather conditions experienced in an area; averages and extremes – Temperature – Precipitation – Sunlight / cloud – Winds Many factors impact climate – Latitude – Altitude and mountains – Dominant air pressure regime, prevailing winds – Ocean proximity and oceanic circulation Solar Energy  Latitude & Solar Energy Subsolar point: where insolation is perpendicular to the surface Tropics receive more concentrated insolation due to Earth’s curvature  Latitude & Solar Energy Good correlation between solar radiation received and temperature  Global Atmospheric Circulation Areas of high (H) and low (L) pressure – Circulation cells – Clouds vs. clear skies Coriolis force deflects air – To right (N) or left (S) Global Atmospheric Circulation  Prevailing Winds Geographic positioning and prevailing winds – Windward sides of continents are likely to have marine climates – Leeward sides are likely to have continental climates – Consider rain shadow deserts Arid (desert) Semi-arid (steppe)  Air Pressure and Precipitation Dominant air pressure impacts precipitation – Low pressure, rising and cooling air, clouds and precipitation – High pressure, sinking and warming air, clear skies  Pressure Cells & Seasonal Shifts Bands of high and low pressure (and associated winds) shift – ITCZ follows subsolar point – Spring/fall equinoxes: ITCZ near equator – Summer/winter solstices: ITCZ at either tropic Impacts wet and dry seasons in tropics  Pressure Zones, Winds and Weather Idealized zones from equator to poles: – Equatorial low; aka intertropical convergence zone (ITCZ) – Trades (NE or SE) – Subtropical highs (STH); high-pressure zones at ~20°– 35° latitude – Westerlies – Sub-polar low – Polar easterlies – Polar highs near the Earth’s poles  Global Precipitation Patterns ITCZ  Monsoons Monsoon: seasonal reversal of winds – Driven by pressure differences Asian Monsoon – Affects India and surrounding areas – Solar heating of continent – Shift in the ITCZ – Wet summer & dry winter  North American Monsoon – Occurs in the southwestern U.S. and northwestern Mexico – Relatively wet summer season – Extreme warm temperatures; thermal low pressure – Draws in moist air from the Gulf of California and Gulf of Mexico – Convergence, lifting, cooling, condensation, precipitation  Ocean Proximity Coastal areas – Moister (usually) with more precipitation – Adjacent water heats/cools slowly – More moderate temperature ranges Continental (inland) areas – Drier – Land heats/cools quickly – More extreme temperature ranges  Maritime vs Continental Climates Land and water – Marine climates are milder and less extreme – Continental climates tend to be much more extreme (range) Calgary, AB Victoria, BC  Ocean Proximity Difference between average January and July temperatures Where do we see large ranges? Small ranges?  Ocean Circulation Winds drive surface ocean currents Ocean currents impact climate  Ocean Circulation Differences in temperature and salinity produce density differences → create deep-ocean thermohaline circulation Ocean Circulation  Ocean Circulation Impacts coastal temperatures – e.g., Scandinavia vs. Alaska  Ocean Circulation Ocean currents – Warm currents cause warmer air temperatures Nordic Europe – Warmer waters make air above moist/unstable warmed – Cold currents cause aridity Atacama desert extra dry  Biomes General classification of terrestrial, large-scale ecosystems – Desert – Tundra (high latitude or high altitude) – Boreal forest / taiga – Temperate forest (deciduous and mixed) – Temperate rainforest (coniferous) – Tropical rainforest – Tropical seasonal forest (summer wet) – Savanna – Temperate grassland (prairie, steppe, etc.) – Chaparral (summer dry; Mediterranean climate) Biomes and Climate  Global Biomes: Forests Net surplus of moisture; high precip. &/or low evap. Discovering Physical Geography. Arbogast et al.  Tropical Rainforest FIGURE 10.7 The tropical rainforest. (a) The layered structure of the rainforest creates a continuous canopy that densely shades the forest floor. (b) Do you see the emergent trees in this tropical rainforest in Malaysia? Discovering Physical Geography. Arbogast et al.  Tropical Seasonal Forest FIGURE 10.9 Example of the tropical deciduous forest FIGURE 10.10 Tropical scrub vegetation in in Brazil. Although this is a low-latitude region, note the Australian Outback. Note the ragged- that the trees are relatively short, and the canopy is looking trees and the scrubby understory. more open than in the tropical rainforest biome. Discovering Physical Geography. Arbogast et al.  Chapparal / Mediterranean https://mediterraneanbiome.weebly.com/vegetation.html  Temperate Forest FIGURE 10.11 Fall colours in Algonquin Park, Ontario. Red and sugar maple trees display brilliant colours in advance of leaf fall in this autumn scene in northern Ontario’s mixed wood forest. Conifers such as balsam fir and eastern white pine are also visible. Note the granite rock outcrop of the Canadian Shield in foreground. Discovering Physical Geography. Arbogast et al.  Temperate Rainforest FIGURE 10.12 Examples of the midlatitude coniferous forest biome. (a) This stand of majestic Douglas fir towers over an understory of Western hemlock in Cathedral Grove in MacMillan Provincial Park, Vancouver Island. (c) Giant redwoods in northern California. These trees are over 100 m tall and can be over 6 m in diameter! Discovering Physical Geography. Arbogast et al.  Boreal Forest / Taiga FIGURE 10.13 Boreal forest in Yukon. Black and white spruce grow sparsely in this section of forest due to its position near the northern limit of the biome where short growing seasons and extreme cold constrain tree growth. Discovering Physical Geography. Arbogast et al. Global Biomes: Grasslands Discovering Physical Geography. Arbogast et al.  Savanna FIGURE 10.14 The tropical savanna. This photograph shows the savanna in Brazil. Here, the vegetation consists of patches of grass that are dotted by isolated trees and woody shrubs. Discovering Physical Geography. Arbogast et al.  Temperate Grassland FIGURE 10.15 The midlatitude grassland biome. The Pampas of Argentina is one of the great grasslands on Earth. Discovering Physical Geography. Arbogast et al. Global Biomes: Deserts Discovering Physical Geography. Arbogast et al.  Hot / Low Latitude Desert FIGURE 10.16 Example of the hot and dry desert biome. The Sonoran Desert in the southwestern United States features tall, columnar saguaro cactus, as well as a variety of smaller cacti and hard-leaved shrubs. Discovering Physical Geography. Arbogast et al.  Semi-Arid / Cold Desert FIGURE 10.17 The semi-arid and cold desert biome. This sagebrush landscape in Monument Valley, Utah, is a nice example of vegetation in the semi-arid and cold desert biome. Discovering Physical Geography. Arbogast et al. Global Biomes: Tundra Discovering Physical Geography. Arbogast et al.  Tundra FIGURE 10.18 The tundra biome. A herd of muskoxen stands its ground in this fall scene from Nunavut. The vegetation here consists of low-growing plant species adapted to the short, cold growing season, primarily grasses, sedges, and dwarf shrubs such as willow, mosses, and lichens. Lichens are a mix of algae, bacteria, and fungi that favour rocky surfaces such as those pictured here. Discovering Physical Geography. Arbogast et al.  Mountain Biomes & Altitude Altitudinal zonation of biomes Drop in atmospheric temperature with increasing altitude – Lapse rate – Varies from ~5 to ~10C per 1000m elevation change Mountain Biomes and Altitude Singh, S.P., Reshi, Z.A., Joshi, R. (2023). Treeline Research in the Himalaya: Current Understanding and Future Imperatives. In: Singh, S.P., Reshi, Z.A., Joshi, R. (eds) Ecology of Himalayan Treeline Ecotone. Springer, Singapore. https://doi.org/10.1007/978-981-19-4476-5_1 Tree Lines and Latitude  Altitude + Latitude By Alexander Keith Johnston -Original publication, first published 1848 in The Physical Atlas, this image comes from The Physical Atlas of Natural Phenomena: Reduced from the Edition in Imperial Folio for the Use of Colleges, Academies and Families;, author Alexander Keith Johnston, publisher W. Blackwood, 1850 https://commons.wikimedia.org/w/index.php?curid=70620463 Snowline altitude lowers as you move away from the equator (and so does the tree line!)  Mountain Biomes and Aspect Aspect / orientation of a slope (which way it faces) – Differences in solar radiation received – Important for microclimates, snow retention, hydrology  Aspect and Microclimate Think: What hemisphere? North S N or South? Orientation controls slope’s exposure to insolation, wind, and precipitation – Microclimate varies (ground temperature and moisture) Slope faces away from the solar radiation tend to be cooler & moister while slopes in direct sunlight tend to be warmer & drier  Aspect and Vegetation Nose Hill Park, Calgary  Mountain Biomes and Precipitation Differences in precipitation received – Orographic precipitation and rain shadow Windward Leeward Mountains and Precipitation Mountain Biomes Cooler Warmer Questions / Comments?  Next time Patterns of Biodiversity (Ch 4) Plate tectonics; part 1 of 2 (Ch 5) Readings Cox et al, Biogeography: an ecological and evolutionary approach – 10th edition (2020): pages 127-153 (Chapter 4) – 10th edition (2020): Chapter 5; “The Evidence for Plate Tectonics” OR – 9th edition (2016): pages 117-143 (Chapter 4) – 9th edition (2016): Chapter 5; “The Evidence for Plate Tectonics”