Disturbance triggers insect outbreaks once populations cross a regulatory threshold
Evidence
Insect herbivore population growth is regulated during nominal environmental conditions by host quality and quantity (Mattson, 1980) interacting with predator and parasite foraging efficiency (Miller, 1980; Schowalter and Whitford, 1979; Tilman, 1978) at levels that cause little mortality to host populations. Disturbance, however, can disrupt regulatory mechanisms and initiate insect herbivore popula tion growth. The time lag before regulatory factors can reestablish control of her bivore population growth depends on a threshold population size. Before the popu lation reaches this threshold, density-dependent and density-independent factors can dampen the perturbation with a minimum time lag; when the population exceeds this threshold, regulatory mechanisms become effective only after a long time lag (Berryman, 1981; Southwood and Comins, 1976). — S. T. A. Pickett and P. S. White, eds., The Ecology of Natural Disturbance and…, 1547
Categorization
- XREF: connects to: Rodent pest explosions actually stem from plant-community derangement — Aldo Leopold, A Sand County Almanac: With Other…, 691; Ecological systems flip catastrophically once crossed thresholds are reached. — Richard J. Lazarus, The Making of Environmental Law, 86; Biological agents and man-caused change both sit on one disturbance continuum. — S. T. A. Pickett and P. S. White, eds., The Ecology of Natural Disturbance and…, 1109 (+4 more)
Broader Connections
- Insect population waves can suppress vegetation across millions of hectares
#expands(0.85) — S. T. A. Pickett and P. S. White, eds., The Ecology of Natural Disturbance and…, 1557 - Monoculture management and fire exclusion promote insect-induced vegetation mortality
#expands(0.75) — S. T. A. Pickett and P. S. White, eds., The Ecology of Natural Disturbance and…, 1582 - Suppressing disturbance makes ecosystems more vulnerable to catastrophe
#corroborates(0.72) — S. T. A. Pickett and P. S. White, eds., The Ecology of Natural Disturbance and…, 2073 - Polyculture fields resist pest outbreaks by hosting predator insects
#contradicts(0.72) — Robin Wall Kimmerer, Braiding Sweetgrass, 486