The Global South's OCBIL Theory Helps Elucidate Evolution, Ecology, and Conservation in Biological and Cultural Diversity

Résumé fourni par la source

Ecological theory has been shaped disproportionately by studies conducted in young, disturbance‐prone, relatively fertile landscapes (YODFELs), mostly in the Global North. Yet, many megadiverse regions in the Global South are dominated by old, climatically buffered, infertile landscapes (OCBILs), where old, extremely impoverished soils, and relative environmental stability result in fundamentally different patterns that rarely conform to theoretical predictions. Here, we examine six case studies that collectively demonstrate how mainstream frameworks often fail to generalize across biogeographic and geological contexts. First, seed dispersal theory, including Janzen–Connell dynamics, predicts distance‐dependent recruitment limitation, but empirical studies in OCBILs reveal short dispersal distances, philomatry, and abiotic filtering as dominant drivers of regeneration instead. Second, classical isolation‐by‐distance expectations in population genetics are commonly reversed in ancient edaphically specialized habitats, where genetic divergence reflects persistent habitat insularity rather than geographic distance. Third, succession theory conceptualized as progressive contrasts with retrogressive trajectories in long‐weathered soils, where productivity, biomass, and diversity decline while stress‐tolerant strategies dominate. Fourth, mycorrhizal ecology illustrates that extreme phosphorus limitation can select for nonmycorrhizal nutrient strategies, challenging assumptions that symbiosis increases with increasing nutrient limitation. Fifth, reduced hybridization, introgression, and hybrid speciation is observed in eucalypts on relatively stable OCBILs of the Stirling Range in the SWAFR, whereas these processes run rampant in adjacent younger landscapes such as steep slopes. Hybrids are not always associated with disturbed habitats, as predicted from Global North studies, and landscape age deserves special consideration. Sixth, Indigenous knowledge systems from southwestern Australia independently recognize enduring ecological distinctions between ancient uplands and younger lowlands. Together, these examples reveal that ecological processes are strongly contingent on landscape age and pedogenesis. Rather than rejecting established theory, we identify a continuum of conditions and argue for broader frameworks that incorporate evolutionary time, soil development and biogeographic history to enhance ecological theory and conservation practice.

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