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Transcript
Lecture 4: Wilderness Ecosystems Outline What: flora and fauna Where: biogeographical zones and ecosystem mosaics Process: cycles, pyramids and relationships Trends: extinctions, re-introductions and climate change Seminar: Guest Lecture – Mark Fisher on Self Willed Land Lecture 4 GEOG3320 - Management of Wilderness Environments 1 1. What: flora and fauna Wilderness management based on ecological considerations Sensitive management of human use to minimise disturbance of natural ecosystems – e.g. limiting use within carry capacities Understanding of basic ecology is essential “The ecosystem is the basic fundamental unit in ecology, because it includes both organisms... and abiotic environments, each influencing the properties of the other and both necessary for the maintenance of life.” (Odum, 1954) Lecture 4 GEOG3320 - Management of Wilderness Environments 2 1. What: flora and fauna (cont’d) Elements – ecosystems are divided into 2 parts: • • abiotic (minerals, climate, water and other non-living elements) biotic (plants, animals, fungi, bacteria and other living organisms) – linked by 2 forces: • • Lecture 4 flows of energy through the ecosystem nutrient cycles within the ecosystem GEOG3320 - Management of Wilderness Environments 3 1. What: flora and fauna (cont’d) Solar radiation = primary energy input – – used by autotrophs (plants) to convert abiotic elements into complex organic substances via photosynthesis heterotrophs (ingestors and decomposers) use autotrophs as food base Gravity – drives long-term movement of material from headwaters to oceans Lecture 4 GEOG3320 - Management of Wilderness Environments 4 1. What: flora and fauna (cont’d) Components include: abiotic factors (sunlight, geology, etc.) – abiotic processes (weathering, evaporation, etc.) – biotic elements (flora and fauna) – linkages and flows of energy, water and nutrients by biotic and abiotic means – temporal fluctuations (diurnal, seasonal, etc.) and spatial variations (location and size) – Lecture 4 GEOG3320 - Management of Wilderness Environments 5 1. What: flora and fauna (cont’d) Wilderness ecosystems – Same components as any other ecosystem • • biotic and abiotic material linked by energy and nutrient flows – Role of man in wilderness ecosystems? – Human influence is lacking (to varying degrees) in wilderness ecosystems True wilderness ecosystem characterised by lack of human influences and impacts Man needs to be included as a transient heterotroph (modern man) or permanent resident heterotroph (primitive peoples) Lecture 4 GEOG3320 - Management of Wilderness Environments 6 1. What: flora and fauna (cont’d) Question: To what extent can primitive peoples (both ancient and modern) be considered a natural part of wilderness ecosystems? Lecture 4 GEOG3320 - Management of Wilderness Environments 7 1. What: flora and fauna (cont’d) Remember... the word wilderness comes from “wild-deor-ness”... place of wild beasts Definition of wilderness wildlife? – Leopold (1933) - those species harmful to or harmed by economic land use – previous focus on larger species – include all species in an ecosystems approach Usefulness of indicator species – larger herbivores and carnivores – at or near top of food chains – general health of lower trophic levels Lecture 4 GEOG3320 - Management of Wilderness Environments 8 1. What: flora and fauna (cont’d) The character of a wilderness is often represented by its resident wildlife “Wilderness without wildlife and wildlife without freedom of wilderness are virtually unthinkable, their interdependency is so formally established in our minds.” (Hendee et al., 1990, p.263) Lecture 4 GEOG3320 - Management of Wilderness Environments 9 1. What: flora and fauna (cont’d) Wilderness dependent wildlife: – species particularly vulnerable to human interference – e.g. Grizzly Bear Wilderness associated wildlife: – species commonly associated with wilderness habitats, but can survive in modified ecosystems – e.g. Mule Deer, Elk, Beaver Common wildlife: – species found in wilderness, but equally at home in higly modified ecosystems – e.g. Racoon Exotic/non-native species – introduced by man and do not naturally belong – e.g. Grey Squirrel in UK Lecture 4 GEOG3320 - Management of Wilderness Environments 10 1. What: flora and fauna (cont’d) Wildlife’s role in wilderness – inseparable part of wilderness • for many people presence of certain animals is tantamount to wilderness (e.g. Greenland) • e.g. Milton (1972) on Alaska refers to Caribou as carrying the soul of the wilderness because of their freedom and vast range • Strong lure for recreation/aesthetics/inspiration • Political focus – role in development, maintenance and modification of soil and vegetation (autotrophic environment) – management preserves these processes by preserving wildlife Lecture 4 GEOG3320 - Management of Wilderness Environments 11 1. What: flora and fauna (cont’d) Wilderness’ role in wildlife – crucial to survival of some species – e.g. Alaskan Brown Bear requires all ingredients of wilderness: • wide range • solitude • particular types of food – role as reservoirs of species – e.g. Pine Martin in Minnesota • much depleted numbers then recent expansion • originated from Boundary Waters Canoe Area Wilderness (BWCAW)? – key to wildlife diversity is diversity of habitat Lecture 4 GEOG3320 - Management of Wilderness Environments 12 2. Where: biogeographical zones and ecosystem mosaics Ecosystem elements arranged spatially into wilderness environments – – – alpine tundra, savannah, mixed boreal forest, etc. examples from web global pattern Within individual wilderness ecosystems variation – – ecosystem mosaics dynamic patchwork of abiotic and biotic elements • • Lecture 4 interaction between the physical and the biological e.g. the role of large herbivores GEOG3320 - Management of Wilderness Environments 13 2. Where: biogeographical zones and ecosystem mosaics (cont’d) Question: What do you think the natural ecosystem mosaic for Britain should look like? Lecture 4 GEOG3320 - Management of Wilderness Environments 14 3. Process: cycles, pyramids and relationships Ecosystem dynamics (succession) – Ecosystems are dynamic entities – Long-term changes and short-term cyclical fluctuations – Succession = the orderly process of ecosystem development involving changes in structure and process • Directional and predictable • Results from modification of physical environment by biotic community Lecture 4 GEOG3320 - Management of Wilderness Environments 15 Ecology and ecosystems (cont’d) Succession culminates in climax (stabilised ecosystem) – maximum biomass – maximum linkage between organisms per unit energy flow Succession involves change from lower to higher order ecosystems towards a climax Lecture 4 GEOG3320 - Management of Wilderness Environments 16 Ecology and ecosystems (cont’d) 2 types of succession: – – primary = slow and natural progression towards climax secondary = rapid changes after interruption of primary succession (e.g. after fire) After interruption succession moves again towards climax Few ecosystem reach climax due to regular interruption by fire, storms, etc. Lecture 4 GEOG3320 - Management of Wilderness Environments 17 Ecology and ecosystems (cont’d) Preditor-prey relations – Focus on large carnivores – Changes in predator populations: • prey populations (density and demography) • sympatric carnivores • all lower levels of ecosystem – Predators as “Umbrella species” • enhance and maintain species diversity – Problems: • low reproductive rates • management increasingly required • replacement by human predation? Lecture 4 GEOG3320 - Management of Wilderness Environments 18 4. Trends: extinctions, reintroductions and climate change Trends in wilderness ecosystems – the shrinking wilderness • reduced habitat and range of wilderness dependent species • effect on isolated populations? • e.g. restricted gene pool and movement – rise in number of extinctions • local and global Lecture 4 GEOG3320 - Management of Wilderness Environments 19 4. Trends: extinctions, re-introductions and climate change (cont’d) Wolf (Canis lupus) – originally the most widespread of modern mammals (circum-polar) – greatly reduced contemporary distribution (mainly North America - Canada and Alaska) – remaining population approx. 50,000 – cultural perception - “evil personified” (Peterson) – competition with humans: • for prey • predation of domesticated livestock – persecution and virtual extinction in Europe Lecture 4 GEOG3320 - Management of Wilderness Environments 20 4. Trends: extinctions, re-introductions and climate change (cont’d) Example: the wolf in Yellowstone – – – – – – – – – – 1875 - Yellowstone designated a national park people like to see elk wolves eat elk wolf exterminated in Yellowstone elk population increases beyond sustainable level due to over grazing NPS introduce winter feeding of elk concentrates elk in feeding areas removes ‘wild-ness’ of elk alternative = cull recent re-introduction of wolves to Yellowstone and areas of Idaho by FWS but not without problems Lecture 4 GEOG3320 - Management of Wilderness Environments 21 4. Trends: extinctions, re-introductions and climate change (cont’d) Question: What indigenous fauna is missing from Britain and what (if any) should be re-introduced and why? Lecture 4 GEOG3320 - Management of Wilderness Environments 22 4. Trends: extinctions, re-introductions and climate change (cont’d) The role of wilderness is important in respect to climate change – preservation of unaltered pristine ecosystems – maintaining ecological and genetic diversity – maintaining areas and routes/corridors for species migration • Lecture 4 horizontally and vertically GEOG3320 - Management of Wilderness Environments 23 4. Trends: extinctions, reintroductions and climate change (cont’d) Preservation – preservation from the effects of human influence and development – value of wilderness ecosystems: • • • Lecture 4 refuges for wilderness dependent species natural laboratories for study and comparative study with altered ecosystems recreational and educational environments GEOG3320 - Management of Wilderness Environments 24 4. Trends: extinctions, reintroductions and climate change (cont’d) Maintaining diversity – bastions of ecological diversity – e.g. NWPS, USA • identified 261 natural ecosystems in USA • all represented in NWPS • 1000’s of human altered ecosystems • BUT majority of diversity in just 261 natural ecosystems – diversity of valuable resources: • pharmaceutical products, timber, water, animal products, etc. Lecture 4 GEOG3320 - Management of Wilderness Environments 25 4. Trends: extinctions, reintroductions and climate change (cont’d) “The job of wilderness management is often to ensure that the dynamics of the ecosystem and the resulting successional change - the natural trajectory of the ecosystem - proceed without disruption or distortion by humans.” Hendee et al. (1990, p.247) Lecture 4 GEOG3320 - Management of Wilderness Environments 26 Reading Agee, J.K & Johnson, D.R (eds) (1988) Ecosystem management for parks and wilderness. University of Washington Press, Seattle. [especially chapters 5 and 6] Hendee, J.C, Stankey, G.H & Lucas, R.C (1990) Wilderness management. Fulcrum Publishing, Colorado. [Chapters 10 and 11] Hendrix, G & Morehead, J (1983) Everglades National Park: an imperilled wetland. in Ambio 12 (3/4) p.153-157. Leopold, A (1949) A Sand County Almanac with essays on conservation from Round River. Ballantine Books, New York. [esp. Chapters ‘Thinking like a mountain’ and ‘Escudilla’ and Part 3] Lecture 4 GEOG3320 - Management of Wilderness Environments 27 Workshop Guest Lecture: Mark Fisher “Self Willed Land” Lecture 4 GEOG3320 - Management of Wilderness Environments 28 Task Web poster proposals – Organise yourselves into groups of between 6 and 8 students – Read web poster handout (online) – Identify a topic for research • See list of examples • Discuss among yourselves • Identify information sources – Complete proposal form (online) for hand in at next week’s lecture Lecture 4 GEOG3320 - Management of Wilderness Environments 29 Next week... 4. The concept of landscape Landscape character: nature and people Perception: evaluation and assessment Policy development Workshop: video “A postcard from the country – The Highlands of Scotland: In search of wilderness” Lecture 4 GEOG3320 - Management of Wilderness Environments 30