Life’s economy is primarily based on collaborative rather than competitive advantage
Daniel Christian Wahl

The concept of adaptation, occurring within species-specific niches, was developed by ecologists over fifty years ago. Exemplified by works such as MacArthur and Wilson’s 1967 book The Theory of Island Biogeography, the “bottom-up” paradigm explain ecological complexity, in terms of interactions among different species, was originally developed by MacArthur and his colleagues, and was based on earlier work on carrying capacity by Lotka and Volterra. THE PRIMACY OF INTRA- AND INTER-SPECIFIC COMPETITION WAS A BASIC ASSUMPTION OF THESE MODELS. This competition forced ecologically related species into different habitats by limiting their potential dietary niches. All parameters are set by the overall carrying capacity (K). This model predicted that the species diversity should be similar in tropical and temperate habitats unless finer subdivision of niches — “niche compression” — had occurred — often signifying an evolutionary process of specialization…

We might be about to see an ecological version of the Modern Evolutionary Synthesis — the Extended Evo-ecological Synthesis, perhaps? John W. Terborgh, in a comprehensive review, compared the various top-down and bottom-up models. In a recent issue of the Proceedings of the National Academy of Sciences, Terborgh suggests the following: 
 “…(e)fforts to understand the ecological regulation of species diversity via bottom-up approaches have failed to yield a consensus theory. Theories based on the alternative of top-down regulation have fared better. Paine’s discovery of keystone predation demonstrated that the regulation of diversity via top-down forcing could be simple, strong, and direct, yet ecologists have persistently failed to perceive generality in Paine’s result. Removing top predators destabilizes many systems and drives transitions to radically distinct alternative states. These transitions typically involve community reorganization and loss of diversity, implying that top-down forcing is crucial to diversity maintenance. Contrary to the expectations of bottom-up theories, many terrestrial herbivores and mesopredators are capable of sustained order-of-magnitude population increases following release from predation, negating the assumption that populations of primary consumers are resource limited and at or near carrying capacity. Predation sensu lato (to include Janzen–Connell mortality agents) has been shown to promote diversity in a wide range of ecosystems, including rocky intertidal shelves, coral reefs, the nearshore ocean, streams, lakes, temperate and tropical forests, and arctic tundra. The compelling variety of these ecosystems suggests that top-down forcing plays a universal role in regulating diversity…” [i]

[i] John W. Terborgh “Toward a trophic theory of species diversity” PNAS | September 15, 2015 | vol. 112 | no. 37 | 11415–11422

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