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Human Resource UseHuman Values & Attitudes (Socio-political)

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Presentation on theme: "Human Resource UseHuman Values & Attitudes (Socio-political)"— Presentation transcript:

1 Human Resource UseHuman Values & Attitudes (Socio-political)

2 Human Land Use Practices 1)Agriculture 2)Suburban Development Let’s pick on Indiana: 97% of land in state = privately- owned In central Indiana, 70+% of land in row crop <10% in forest Urban sprawl intensifying

3 Human Impacts Ecosystem simplification: elimination of species from food webs via human alterations to land Example: vertebrate communities in ag. landscapes

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5 Intensive Agriculture & Clean Farming

6 Timber Extraction & Fragmentation

7 Formation of Terrestrial “Islands”

8 Oceanic Island = Terrestrial Island ?????

9 Species-Area Relationship S = cA z S = # of species A = island area Positive correlation between island size & number of species Applies to terrestrial “islands” also

10 Island Biogeography equilibrium model suggesting that the number of species occurring on an island represents a balance between immigration (in) and extinction (out) Robert MacArthur & E.O. Wilson

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12 Habitat Fragmentation Process of breaking contiguous unit into smaller pieces; area & distance components Leads to: < remnant patch size > edge:interior ratios > patch isolation < connectivity Community & Ecosystem processes altered

13 Formation of Terrestrial “Islands”

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15 #patches Patch isolation Patch size Edge

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20 What about aquatic systems?

21 What about aquatic systems? Con.Bio 12(6)

22 Increased Edge Habitat

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24 Habitat Fragmentation First-Order Effects: fragmentation leads to change in a species’ abundance and/or distribution Higher-Order Effects: fragmentation indirectly leads to change in a species abundance and/or distribution via altered species interactions

25 Habitat Fragmentation area-sensitive species: species that require minimum patch size for daily life requirements Edge effects: influence of factors from outside of a patch

26 Edge Effects Habitat surrounding a patch can: -change abiotic conditions; e.g., temp. -change biotic interactions, e.g., predation Example of nest predation = edge effect of approximately 50 m into forest patch But can extend 100’s of meters….maybe km’s

27 Edge Effects How does patch size (in a landscape) & shape affect amount of edge? Groups – give me a mathematical example with forested landscapes that have timber extraction via clearcutting

28 Exponential vs. Logistic No DD All populations same DD All populations same No Spatial component

29 Incorporating Space Metapopulation: a population of subpopulations linked by dispersal of organisms subpopulations separated by unsuitable habitat subpopulations differ in population size & distance between

30 Metapopulation Model p = habitat patch (subpopulation) c = colonization e = extinction

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32 Another Population Model Source-sink Dynamics: grouping of multiple subpopulations, some are sinks & some are sources Source Population = births > deaths = net exporter Sink Population = births < deaths

33 <1 >1 Source-sink Dynamics

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36 Corridors

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38 Who Cares? Why bother discussing these models? Metapopulations & Source-sink Populatons highlight the importance of: habitat & landscape fragmentation connectivity between isolated populations genetic diversity

39 Vancouver Island marmot (Marmota vancouverensis) Isolated from hoary and Olympic marmots ~100 left

40 Vancouver Island marmot (Marmota vancouverensis) Natural tree succession

41 Vancouver Island marmot (Marmota vancouverensis) Logging – disjunct patches - max. dispersal = 7 km Climate Prey-Predator Dynamics

42 Differential Sensitivities to Habitat Alteration Niche breadth (diet & habitat) – inverse relation Range periphery = more sensitive (W & N) Body size = mobility (allometric relation) Social and territorial behavior (limited K) Swihart et al. 2003

43 Ways to Manage 1) Featured Species Mgt –single species –particular purpose –e.g., white-tailed deer –could also include “umbrella species” and “flagship species” or “sensitive species”

44 Ways to Manage 2) Species Richness Mgt –maintain diversity and certain # of each species (follow MVP concept) 3) Indicator Species Mgt –use a species (or group of species) to monitor environmental conditions –not necessarily managing for these spp. –bioindicators, biosentinels, “canary in coal mine”

45 Ways to Manage 4) Guild Mgt or Life-Form Mgt –grouping of species based on use of same type of resources (e.g., foraging guilds)


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