Shrubland diversity arises from varied disturbance rather than a single optimum

Evidence

This view of the relationship of the fire cycle to shrub community diversity differs from other recent disturbance-diversity hypotheses (see, e.g., Loucks, 1970; Connell, 1978; Huston, 1979) in that it does not necessarily invoke nonequilibrium conditions (see also Denslow, Chapter 17, this volume). Indeed, it speaks more to the evolution of richness than its maintenance, and may account for the high richness and endemism of many shrubland floras. There are many more ways to succeed in a shrubland than analysis of the mature community or mean disturbance conditions might suggest. To the extent that variability in shrubland species composition is related to variability in fire regimes and fire effects, it may be necessary to incorporate variation into shrubland management strategies. In such systems, the concept of an optimal fire regime may be meaningless. — S. T. A. Pickett and P. S. White, eds., The Ecology of Natural Disturbance and…, 672

Categorization

• DEFINE: Distinguishes the regeneration-niche view from nonequilibrium disturbance-diversity hypotheses (Connell 1978, Huston 1979) — the key theoretical vocabulary distinction a reference reader wants.
• XREF: The ‘optimal fire regime is meaningless’ conclusion reframes management; connects to the Soundscape treatment of disturbance/breakpoints as variable rather than regime-fixed. — connects to: Common juniper and multiflora rose only establish in grazed pastures — Tom Wessels, Forest Forensics: A Field Guide to…, 95; Landscape-level diversity in the BWCA depends on a fire-made mosaic of successional stages. — Miron L. Heinselman, Fire in the Virgin Forests of the…, 411; Fire suppression restructures the whole ecosystem and reduces overall wildlife diversity — Miron L. Heinselman, Fire in the Virgin Forests of the…, 442 (+6 more)
• SEED: A usable provocation for the landscape course: variability itself as the ecological norm argues against single-regime prescriptions in land management.

Broader Connections

• Unrelated sessile communities obey the same disturbance-diversity rule #expands (0.85) — Robin Wall Kimmerer, Gathering Moss, 300
• The same disturbance-diversity dynamics governing forest trees also structure moss communities on logs #exemplifies (0.80) — Robin Wall Kimmerer, Gathering Moss, 371
• Symmetrical competition makes disturbance-diversity peaks unpredictable #qualifies (0.78) — S. T. A. Pickett and P. S. White, eds., The Ecology of Natural Disturbance and…, 1006
• Each woody plant growth form is efficient only within a narrow disturbance range #contradicts (0.75) — S. T. A. Pickett and P. S. White, eds., The Ecology of Natural Disturbance and…, 1348