Lecture 1: What is Ecology? Why it is important for NRM?

Transcription

1 Lecture 1: What is Ecology? Why it is important for NRM?

2 The three inter-related global challenges to sustainable development

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4 Sustainability Major components: Environmental Economic Social Political

5 Why Precautionary Principle in Natural Resources management? Why ecology? Asserts there is a 'premium' on a cautious and conservative approach to human interventions in the natural environment where our understanding of the likely consequences is limited and there are threats of serious or irreversible damage to natural systems and processes (As noted by Myers 1993 in Barbier, Burgess and Folke 1994, 172).

6 What is Ecology? Ecology is a branch of science that systematically studies the relationships between living organisms (biotic component) and the physical and chemical environment (abiotict component) in which they live. An ecosystem includes living organisms in a specified physical environment, the multitude of interactions between the organisms, and the non-biological factors in the physical environment that limit their growth and reproduction, such as air, water, minerals, and temperature. The study of interactions between: Organisms and organisms Organisms and environment

7 Why Study Ecology? to provide a broader and deeper understanding of the natural process by which natural resources are created and maintained; to understand some of the natural laws that impose limitations on the interaction of organisms (including humans) with their living and nonliving environment; to show the specific ways in which human interaction with nature has been incompatible, and to identify some of the important links between ecology and economics, two disciplines which are imperative for a holistic view of natural resource problems and issues.

8 Why Study Ecology? Ecological studies give us the scientific foundations for our understanding of natural resources (agriculture, forestry, fisheries etc.); Ecology also gives us the basis for predicting, preventing and remedying ecological problems, pollution etc. Ecology also help us to understand the likely consequences of environmental interventions and provide the rationale underpinning biological conservation.

9 Ecology? Ecology is an integrated and dynamic study of the environment.

10 To study Ecology involves For non-living (abiotic) Climatology Hydrology Oceanography Physics Chemistry Geology soil analysis, etc. For living (biotic) animal behavior Taxonomy Physiology mathematics (population studies) etc.

11 Levels of organization from genes to ecosystems Biosphere Ecosystems Communities Populations Organisms Organs Tissues Cells Genes ECOLOGY ORGAN SYSTEM LEVEL Nervous system ECOSYSTEM LEVEL Singharaja forest COMMUNITY LEVEL All organisms in Singharaja forest POPULATION LEVEL Group of flying foxes ORGANISM LEVEL Flying fox ORGAN LEVEL Brain CELLULAR LEVEL Nerve cell MOLECULAR LEVEL Molecule of DNA Genes Brain Nerve TISSUE LEVEL Nervous tissue Spinal cord

12 Levels of Organization Individual- one organism (living) Ex a sambar Population- groups of individuals that belong to the species and live in the same area (defined area) (living-living same species) and usually isolated to some degree from other similar groups Ex many sambar

13 Levels of Organization Community- groups of different populations (more than one population or different groups of species) and coexist in the same habitat or area and interact through trophic and spatial relationships Ex many groups of sambar, trees, grass, tigers (all living) Ecosystem- a community of organisms and their physical environment interacting as an ecological unit. All organisms in a particular area along with the nonliving (living and nonliving) Ex many groups of sambar, trees, grass, tigers, rocks, water, mountains

14 Levels of Organization Biome- group of ecosystems that have the same climate and similar dominant communities Biomes: tropical rain forest, tropical dry forest, tropical savannah, temperate grassland, desert, temperate woodland and shrubland, temperate forest, northwestern coniferous forest, boreal forest (taiga), tundra, mountains and ice caps Biosphere- all of the planet where life exists, includes land, water, and, air Life extends 8 km up and 11 km below the surface

15 Levels of Organization

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18 Habitat vs Niche In an ecosystem, organisms live in a habitat and organisms fit into a Niche of the environment. Habitat - an area where an organism lives Niche - an organisms role in its environment The long version full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions. Includes where in the food chain it is, where an organism feeds Habitat is like an address in an ecosystem and a niche is like an occupation in an ecosystem.

19 Niche: The role or job that each species performs within an ecosystem. This role could be as a decomposer, a consumer, a producer, or a combination of these. Niche

20 Habitat: An area that supports a particular species by providing survival essentials such as food, water,nutrients and shelter. Polar bear habitat and jack pine habitat are two examples. Habitat

21 Population, communities and ecosystems are terms which have precise meanings in ecology. Did you understand the terms? Take home quiz No 1: Terms Explain what do you understand by the terms population, community, ecosystem, niche, habitat and to me

22 Geological history

23 Continental drift theory

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26 Other land uses, 21.5% Homegarde ns, 14.8% Tea, 3.4% Rubber, 1.8% Coconut, 6.0% Other perennial crops, 11.0% Paddy, 8.8% Forest plantations, 1.4% Sparse forests, 7.2% Closed canopy natural forests, 22.4% Other non perennial crops, 1.5%

27 No of Orders in the world No of Orders in Sri Lanka % No of Families in the world No of Families in Sri Lanka % Sub Class Magnoliidae Hamamelidae Caryophyllidae Dilleniidae Rosidae Asteridae Alismatidae Arecidae Commelinidae Zingiberidae Liliidae Source: DSA Wijesundara

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29 Approaches in Ecology? Holistic approach (simultaneous considerations of all aspects) Ecosystem approach focus on exchange of energy and matters between living and non living components (functional relationships between organisms) Community approach (synecology) (concept of succession and climax biotic components) Population approach (autecology) growth, maintenance and behavior of populations. Habitat, distribution, and evolution history. Habitat approach Evolutionary and historical approach (evolutionary ecology, palaeoecology, historical ecology)

30 Introduction to diversity and biodiversity

31 THE RULES OF ECOLOGY 1. Everything is connected to everything else. 2. Everything must go somewhere. 3. There is no such thing as a free lunch. To understand any system you must understand the next larger system.

32 Nothing in biology makes sense except in the light of evolution Theodosius Dobzhansky 1973 The ecological theater and the evolutionary play evolutionary events occur because of the relationships between an organismic unit and their environment

33 tie between ecology and evolution natural selection 1. The theory of natural selection is a truly fundamental unifying theory of life 2. A thorough appreciation of it is essential background for understanding evolutionary ecology 3. Natural Selection comes as close to being a fact as anything in biology

34 Natural Selection is synonymous with Evolution - Evolution refers to temporal changes, whereas natural selection specifies one particular way in which these changes are brought about - Evolution more specifically refers to a change in gene frequencies or descent with modification

35 ECONOMY ENV T SOCIETY ECO- ECONOMY SOCIETY SYSTEM HEALTH TRADITIONAL DECISION MAKING ENVIRONMENT ECOSYSTEM-BASED DECISION MAKING

36 References Rebecca R. Sharitz, Lindsay R. Boring, David H. Van Lear and John E. Pinder (1992) Integrating Ecological Concepts with Natural Resource Management of Southern Forests. Ecological Applications Vol. 2, No. 3 (Aug., 1992), pp