High dispersal capacity organisms (Vagile species) Home range size in excess of 5km2 Potential for habitat utilization across a broad geographical range Non-aquatic. Non-avian

Fragmentation: A physical definition ‘The creation of remnants’ (Saunders et al. 1991) Remnant: Any patch of native vegetation around which most or all of the original vegetation has been removed. (Saunders et al. 1987)

Island biogeography (Darwin) (Soule and others) Minimum Critical Size of Ecosystems Project (Lovejoy et. al)

Fragmentation: A dynamic definition ‘The disruption of continuity in pattern or process’ (Lord and Norton, 190) ‘Interchanges that once took place between the fauna and flora of particular regions are precluded, or facilitated, with unknown evolutionary consequences’

Non-fragmented Landscapes (Hypothesis) Habitat gradient Less edge contrast Rich internal habitat structure Metapopulation dynamics Balance between colonization and extinction Balance between exclusion and dispersal The ‘Shifting Mosaic’

The Shifting Mosaic ‘Stability and change as two aspects of the same integral process’

Fragmented Landscapes (Hypothesis) Internal uniformity Sharply defined edges Habitat discontinuity Disruption in metapopulation dynamics Extinction dominates colonization Patterns of exclusion and dispersal are altered, with uncertain consequences

Scales across which Fragmentation must be assessed Temporal Spatial Trophic

Questions related to the impact of Fragmentation In it’s original state, was the landscape heterogeneous? What level of stability did it have? Are barriers ’dams’ or a ‘filters’?

Fragmenting forces Development Agriculture Transportation grids Habitat alteration Behavioral constraints Corridor considerations Ecology Exposure Scale

Impacts of fragmentation on overall ecosystem health Immediate Exclusion Crowding effect Extended Edge effects* Altered trophic patterns Microclimate shifts Avenues for entry by ‘weedy’ species Genetic consequences Shifts in metapopulation dynamics Vulnerability to stochasticity Overall Loss of diversity

Characteristic leading to species vulnerability Naturally rare? Wide ranging* Nonvagile Extended life cycle/K-selected* Succession/Heterogeneity dependent? Large patch requirements/interior dependence? Susceptible to exploitation, or other ‘take’* Limited adaptive potential?

Impacts of fragmentation on Canis lupus

Characteristics of C. lupus that increase vulnerability to fragmentation Naturally rare* Wide ranging* Low fecundity Extended life cycle Large patch requirement/interior dependence* Susceptibility to exploitation/take *Qualifications

Is there historical evidence that habitat fragmentation has impacted N.American populations of C. Lupus? (Importance of distinguishing between the consequences of direct take, and the impacts of fragmentation.

Current distribution of ‘contiguous’ Canis lupus populations (Wayne et.al 1991)

Coyote China Portugal Israel Estonia Italy Mexico Iran Minnesota-NWT Manitoba N. America Alaska, NWT* Mitochondrial variation in worldwide C.lupus populations (Wayne et.al 1991) Genetic Evidence

Genetic distances (microsatellite) between Canis lupus populations in the inland Northwest (Forbes and Boyd, 1996)

Current demography of a C.lupus population in a fragmented landscape.

Canis lupus distribution within the Great Lakes region (Mladenoff et al 1995).

Wolf habitat probability for Minnesota, northern Wisconsin, and Upper Michigan Mladenoff et al (1995)

Log road density (km/km2) Wolf pack probability (log) Wolf pack presence as a function of road density Mladenoff et al (1995)

Wolf territorial size (km2) Deer/ km2 Wolf pack territory size as a function of deer abundance. (Wydeven et al. 1995) ‘Within favorable habitat, ungulate density explains 72% of variation in wolf density’ (Fuller 1989).

Review: ‘This semi-wild, human dominated landscape produces high prey availability, but also results in fragmented wolf habitat.’ (Mladenoff et al. 1997) Impoverishment of the northern boreal ecosystem at large. Potential for impacts on a multitude of levels as human land-use patterns evolve.

Fragmentation of Arctic ecosystems

ANWR and Prudhoe Bay

(Central North Slope)

ANWR (Arctic National Wildlife Refuge)

Temporal Spatial Trophic

Findings Negative correlation: caribou density/road density (Cameron et.al 1992) Insect avoidance Predator avoidance Available habitat Optimum habitat Differential response of individuals based on maternal status (Bergerud, 1972).

Findings Overall ‘favorable’ demography in the Central Arctic caribou herd (Cronin et.al 1998). Confounding factors Temporal: The baseline for demography in the CACH is uncertain. Trophic: Disagreements as to the importance of predator interactions

Summary thoughts Evaluate the impact of fragmentation across time, space, and trophic level Avoid the ‘many deer equal a healthy system’ syndrome. Recognize that impacts are diverse, and not all may be ‘bad’. Recognize and manage for the ‘shifting mosaic’

Thought Question Can human development and the ‘shifting mosaic’ coexist? How?