First of all, how the top-down force emerged, which drove NGOs to participate in policymaking?
Herbivory is an important top-down force on coral reefs that regulates macroalgal abundance, mediates competitive interactions between macroalgae and corals, and provides resilience following disturbances such as hurricanes and coral bleaching.
Bottom-up and top-down forces simultaneously influence benthic communities.
In contrast to aquatic systems, where trophic cascades and top-down forces dominate, it has been postulated that terrestrial systems are regulated mainly by bottom-up forces.
Moreover, we identified bottom-up and top-down forces governing the interactions between granivores (birds, ants, and small mammals) and seed availability/production at the community scale.
Mixed-severity regimes are produced by interactions between top-down forcing by climate and bottom-up shaping by topography and the flammability of vegetation, although specific effects may vary widely across the region, especially the relation between aspect and fire severity.
"This top-down, force-them-to-comply approach is really dissonant with that".
In addition, studies focusing on top-down forces have revealed significant impacts of predators on lower trophic levels, such as herbivorous arthropods [7] [11].
In each case, herbivorous arthropods play a decisive role in ecosystem functioning because, as mid-trophic level species, they are influenced by bottom-up and top-down forces.
However, two general classes of hypotheses have been proposed: top-down forcing, primarily by predation [4], [5]; and bottom-up forcing through changes in prey resources due to climate change or competition with commercial fisheries [4], [6], [7].
Aquatic food-chains are classical systems for studying bottom-up and top-down forces [7], [8], [9], [10], [11], particularly during spring with its frequently observed dramatic decrease in zooplankton and the subsequent increase in phytoplankton [11], [12].
