Landscape Disturbance Disturbance defined as Relatively discrete event

Landscape Disturbance • Disturbance defined as: – Relatively discrete event in time – Disrupts possible multiple hierarchal levels White and Pickett 1985

Landscape Disturbance • Disturbance defined as: – Changes resources, substrate, or physical environment White and Pickett 1985

Landscape Disturbance • Disturbance defined as: – Catastrophes to more subtle fluctuations – Ultimately causes “significant change in system” White and Pickett 1985

Landscape Disturbance • Perturbation – change in parameter (state variable); departing from normality

Landscape Disturbance • Characteristics of Regime: – – Area/size Spatial dist’n Frequency Recurrence interval – – Predictability Intensity/severity Synergisms Feedbacks

Landscape Disturbance • Type Agent – Physical – Biological – Interaction • Origin of Agent – Endogenous – Exogenous

Disturbance Types

Landscape Disturbance • Disturbance history – Time scale – Context

Landscape Disturbance • Complexity of interactions – Macroclimatic patterns – Landscape position – Vegetation Boose et al. 1994

Landscape Pattern & Spread of Disturbance • Generalities possible? – If disturbance spreads within same cover type, then greater heterogeneity should retard spread (e. g. , spruce budworm, lower intensity fires)

Landscape Pattern & Spread of Disturbance • Generalities possible? – If disturbance spreads between cover types or is edgeenhanced, then increased heterogeneity should enhance spread (e. g. , windthrow, tent caterpillar)

Landscape Pattern & Spread of Disturbance • Generalities possible? – If disturbance is severe enough or of large enough extent, then may function independent of landscape pattern

Disturbance Regimes in Michigan • Are disturbance regimes evident in Michigan today? • What types exist?

Disturbance Regimes in Michigan • Are disturbance regimes evident in Michigan today? • What types exist? • Can they be reintroduced? Mack Lake Fire, 1980 First 6 hours 1 human life 44 homes 20, 000 A After 30 hours, fire contained within 24, 000 A area

Disturbance Regimes in Michigan • Are disturbance regimes evident in Michigan today? • What types exist? • Can they be reintroduced? What data are needed? Cutting pattern in Jack pine. Kirtland Warbler management area, Huron-Manistee National Forest, Linda Haugen