Community interactions
Competition occurs when organisms reduce each other’s access to shared limiting resources. Partitioning resources can reduce overlap and support coexistence. Predation and herbivory can affect lower trophic levels directly and indirectly; removing a predator may change producers through a trophic cascade. A keystone species has an effect disproportionate to its abundance. Interaction labels summarize effects under particular conditions; a relationship can shift when environmental costs and benefits change.
If wolves reduce browsing by deer, woody plants may increase. The indirect plant response depends on the actual food web rather than a universal predator-removal rule.
Do not assume every species removal causes all other populations to move in the same direction. Trace each interaction.