Factors Regulating Population Stand Structure in Blackbrush (Coleogyne ramosissima: Rosaceae), a Masting North American Desert Shrub

Blackbrush (Coleogyne ramosissima Torr.) is the dominant shrub on three million hectares across transition zone between western North American warm and cold deserts. This paper presents a study of blackbrush population structure at stand level sixteen sites species range. New stand-level information then integrated with what already known about ecology to explore consequences several unusual features life history, including its masting reproductive strategy, interactions heteromyid rodents that are both seed predators dispersers, ability form ‘seedling banks’ growth-suppressed individuals, often within crowns adult conspecifics. It complements earlier work showing stands organized inter-clump intra-clump levels. Each clump represents an establishment nexus where younger individual genets replace older over extended time period. Inter-clump thus determined by rate new clumps rather than individuals. has resulted in contrasting structures response rodent community composition, disturbance regimes, climatic variability leading trailing edges current distribution eastern Mojave Desert Colorado Plateau regions. Because likely disperses too slowly track anthropogenic climate change, assisted migration wild-collected seeds may be necessary promote continued survival dominance.