Population and community-level consequences of fragmentation interrupts ecological patterns and processes reduced habitat patch area edge effect increased patch isolation –decreased successful movement (immigration and emigration) –increased likelihood of local extinction

Processes operating between fragments dispersal –increasing fragmentation decreasing colonization rates –leads to decreasing # of species within patch –increasing risk of local extinction of species within patch

Processes operating between fragments dispersal matrix –disturbed/converted habitat surrounding fragments –potential roles? matrix

Persistence of populations In which directions would you predict net movement of individuals? Which populations are more likely to persist? why? Disappear? What are the factors most important in determining a population’s likelihood to persist? Which populations, if they disappear, are most likely to be recolonized?

Grizzly bear 50,000 historic estimate Persecution and habitat changes == about 1,200 wild grizzlies remain in lower 48

Grizzly bear ecosystems <20 0? > ?

Y2Y Yukon to Yellowstone Conservation Initiative Goal: maintain and sustain region to allow wilderness, wildlife, native plants, and natural processes to function as an interconnected web of life Partnerships of NGOs, businesses, foundations, concerned citizens, scientists Based on science Balance area needs

Cascade Land Conservancy In conjunction with members of communities, work toward large- scale conservation Habitat Lands Farmland Working Forests Parks, Trails and Open Spaces Shorelines and Estuaries

Natural Landscapes are also heterogeneous Why?

Natural Landscapes are also heterogeneous Why? Topography and climate

How Rain Shadows Form wet W sides, dry E sides Olympics Puget Trough Cascades Ellensburg North Bend Ppt ”Ppt 10-12” Ppt 36” Seattle Ppt 100” Ppt 10-12” Rainshadows Pacific Ocean Air mass

Generalized Forest Zones of the Washington Cascades Cross-section of Cascades Western hemlock Pacific silver fir Mountain hemlock Alpine Spruce-fir Douglas-fir Ponderosa pine Shrub-steppe WESTEAST

Structural diagram for successional seres in Douglas-fir forests (Franklin and Spies 1991) Natural succession

Structural diagram for successional seres in Douglas-fir forests (Franklin and Spies 1991) Succession from different sources of disturbance: fire, cutting Natural succession

Disturbance: an event that causes a change to resource availability, substrate, or the physical environment –Fire, wind storm, insect outbreak, floods Disturbance regime: spatial and temporal dynamics of disturbances over a longer time period –Defined by frequency, intensity, severity, size Natural Disturbances

Regional & landscape scale patterns of forest disturbance Turner et al from Turner, et al (2001)

Patch Dynamics: over space and time, disturbances create a mosaic of patches of various sizes, shapes, and successional stages across an area

Role of Fire Habitat diversity: landscape mosaics uneven-aged stands (in most cases) dead and dying trees Nutrient release Leads to a greater diversity of wildlife

Landscape mosaic created by the 1988 Yellowstone fires

Remain after disturbance Influence ecological effects of disturbance and patterns of succession Snags, logs, roots, seeds Ecological Legacies Scrub Oak: Survive fires only by resprouting

Wildlife Responses to Fire

Serotinous Cones Sealed by resin Opened by fire A new generation grows (ex Jack Pine)

Winners and Losers Disturbances change habitat naturally Some wildlife increase = “winners” Some wildlife decrease = “losers” Some generalists show little change Disturbance is not “good” or “bad” for all wildlife

How Did Fire Affect PNW Forests? Historical Fire Regimes High Severity –Infrequent (100+ yrs) and stand-replacing Mixed Severity –Less frequent (25-75 yrs) and a mix of severities Low Severity –Frequent (5-15 yrs) but low intensity

Stimulates new growth Higher protein Higher digestibility Attracts moose, elk, deer, and their predators (wolves) plus bears Fire improves browse quality

Pyrophilic Insects Barbeque Beetle Infrared sensors on abdomen to detect fire from a distance With predators and sticky tree resin gone after fire, good conditions for mating Xenomelanophila miranda beetle Mate on charred trees soon after fire

Black-backed Woodpecker Nearly restricted in its habitat distribution to standing dead forests created by stand-replacement fires Feed on larvae of the black fire beetle

Longleaf Pine of the Southeast Fire-dependent ecosystems Historically, surface fires every 3-5 years –Ignited by lightning and Native Americans Now maintained by prescribed burning

Red-cockaded Woodpecker Endangered (SE) Requires large, live longleaf pine trees Longleaf is a fire-adapted species

Lives in large LIVE longleaf pine Drills holes around the cavity Resin flows – defense against snakes Longleaf pine type one of most endangered forest types in world – 99% gone

Prescribed burning used to maintain Longleaf Pine savanna There is no ecological equivalent to fire

Kirtland’s Warbler Endangered species In danger of extinction until an out-of-control fire triggered a population revival Nests in young Jack Pine, a fire- dependent species with serotinous cones

Wildlife Management Stand-replacement fires may be necessary for long- term maintenance of many pyrophilic wildlife populations Such fires are controversial due to human safety

Wildlife Management Salvage cutting may reduce the suitability of burned- forest habitat by removing the most important element-standing: fire-killed trees needed for foraging and nesting (ecological legacies) Prescribed burning becoming more accepted as a tool to reduce fuel loads

Persistence of Change Similarity of Alteration to Natural Habitat High Low High Agriculture Timber Harvest Urbanization High Low Effect of Fragmentation Landscape Alterations Can Profoundly Affect Natural Ecological Systems