Lecture 24 Plant Ecology Understanding the spatial pattern of plant diversity Ecology: interaction of organisms with their physical environment and with one another 1
Such interactions occur on multiple scales: from population, community, ecosystem, to biome Population: a group of individuals of a single species live close together at the same time. Members of a population may harm each other (compete for resources and spread diseases), help each other (attract pollinators and seed dispersers), and can potentially mate with each other. Why populations cannot grow denser and denser? Organisms are never alone Habitat: the set of conditions in which an organism lives. Habitat components: Biotic same species, other plant species, animals, fungi, protists, prokaryotes. Can be pollinators, seed dispersers, parasites, symbionts, etc. Abiotic - non-living physical phenomena such as temperature, climate, soil, altitude, latitude, drought, salt stress, disturbances such as fires or floods, or avalanches. 2
Community: all of the populations together in one place (plants, fungi, animals, protists, and prokaryotes). Species richness Species interaction: competition, predation, mutualism etc. Ecosystem: the community along with the physical, non-living environment Raymond Lindemen first proposed the idea of ecosystem in 1942 by studying the Cedar Bog Lake in Minnesota, when he was a graduate student at University of Minnesota Raymond Lindemen (1915-1942) 3
The 1942 view of the Cedar Bog Lake ecosystem by Lindemen Community and its abiotic environment should be studied together Energy flow trough trophic levels Current ecosystem research at Cedar Creek What types of ecosystems are present in Cedar Creek? What would be an example of ecosystem research topic? https://vimeo.com/232084985 4
Biome: groupings of many ecosystems characterized by the distinctive aspects of the dominant plants. Determined by temperature, soil, and water and light availability. The Earth s biomes 5
Tropical rain forests non-seasonal climate, abundant precipitation Multiple canopy layers, densely growing plants, non-deciduous, highly diverse Tropical rain forests plants growing on plants Direct nutrient cycling via mycorrhizae 6
Biomes in seasonal climates What makes seasons? Summer we point toward sun Winter we point away from sun Desert biome low, seasonal rainfall 7
Desert biome Succulent plants, some with CAM photosynthesis Succulent stem: cactus Succulent leaves - yucca Biological crusts fungi, algae, lichens, mosses Desert biome Deep rooted trees and shrubs Joshua trees Spring flowering with rains Mesquite tree Creosote shrub 8
Grasslands Relatively low precipitation, hot summers, frequent fire Grasslands seasonal moisture, hot summers, frequent fires Large grazing animals Burr oak Deeply rooted perennials, fire adapted plants 9
Temperate deciduous forest precipitation throughout the year, cold winter, lack drought, relatively lone growing season Temperate deciduous forest deciduous trees with dormancy, a few conifers Dense forest, several canopy layers Spring flowering light availability Common trees of temperate forests Many trees are wind pollinated 10
Boreal coniferous forest low precipitation, low winter temperatures, short growing season http://www.lakeplacidlandconservancy.org/ Boreal coniferous forest evergreens, deciduous trees, mosses, lichens Mosses, lichens Nutrient poor, acidic soils Coniferous (Gymnosperm) trees: Spruce, fir, tamarack Deciduous trees: Aspen, birch 11
Biomes of Minnesota Cold 1981-2010 annual mean temperature of Minnesota Warm 12
Dry 1981-2010 annual precipitation of Minnesota Wet Biome boundaries maintained by temperature, precipitation, and fire Dry Cold Deciduous forest Fire Wet Warm https://www.dnr.state.mn.us/climate/summaries_and_publications/normalsportal.html 13
Soil layers, or horizons Decay is slow and little organic materials Decay is more rapid and the soil more fertile Highly fertile from dead plant materials Organic materials: roots, arthropods, earthworms, fungi, and decay products Less organic materials Broken-down rocks Which of the following statements about soil is FALSE? a. The A horizon has the greatest biological activity. b. The A horizon is the topsoil. c. The B horizon is the soil base and is mainly consists of rock fragments. d. The C horizon has the least organic materials among the three horizons 14
Why monocot trees such as palms cannot survive cold climate but grass can? Hint: think about what happens if monocot vessel elements are damaged? Will any new ones be made to replace them? Minnesota is getting warmer, even if it does not feel so this year 15
It rains more in Minnesota 16
Mega-rains are more frequent Lyme disease spreads in Minnesota 17
Aspen and tamarack are declining in northern Minnesota due to warming and eastern larch beetle 18
Similar trend for moose Shifting biomes 19
Global nutrient cycles: N and C N cycle 78% of the atmosphere is N 2 20
The chief reservoir of nitrogen is: a. the soil. b. the ocean. c. dead organic material. d. the atmosphere. In the process of nitrogen fixation, is converted to ammonium. a. nitrate b. ammonia c. amino acid d. nitrogen gas 21
Primary productivity CO 2 uptake due to plant and algal photosynthesis http://www.nature.com/scitable/knowledge/library/terrestri al-primary-production-fuel-for-life-17567411 22
Which of the following processes does not add carbon to the atmosphere? a. respiration b. use of fossil fuels c. land use change d. photosynthesis Lecture 24 Study Guide Ecology: interaction of organisms with their physical environment and with one another Population: a group of individuals of a single species live close together at the same time. A habitat is the set of conditions in which an organism lives. Components of habitat: Abiotic: non-living components such as temperature, moisture, latitude (day length), disturbances. Biotic: all living components. Community: all of the populations together in one place (plants, fungi, animals, protists and prokaryotes) Ecosystem: the community along with the physical, non-living environment 23
Biome: groupings of many ecosystems characterized by the distinctive aspects of the dominant plants. Determined by temperature, soil, and water and light availability. Major biomes in the world: tropical rain forest, desert, grassland, deciduous forest, and coniferous forest. The last three each occupies roughly 1/3 of Minnesota Describe the differences in temperature, soil, and water availability in the three major biomes in Minnesota. Know the three horizons in soil For N cycle know: N 2 fixation: biological (microbes in root nodules and free-living), industrial processes, lightning, volcanoes Only fixed N forms are accessible to plants and animals Know about the carbon cycle. Know how CO 2 is added to the atmosphere and is removed (such as photosynthesis). 24