Human Resource UseHuman Values & Attitudes (Socio-political)

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

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

Intensive Agriculture & Clean Farming

Timber Extraction & Fragmentation

Formation of Terrestrial “Islands”

Oceanic Island = Terrestrial Island ?????

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

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

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

Formation of Terrestrial “Islands”

#patches Patch isolation Patch size Edge

What about aquatic systems?

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

Increased Edge Habitat

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

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

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

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

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

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

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

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

<1 >1 Source-sink Dynamics

Corridors

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

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

Vancouver Island marmot (Marmota vancouverensis) Natural tree succession

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

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

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”

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”

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)