Rosenzweig-MacArthur simulations on community ecology of Nagcarlan Kingfishers: Niche displacement and coexistence of upland Alcedinidae in Santa Barbara River, Laguna, Philippines

AUTHOR(S)

Jericho A. Trio

ABSTRACT

—— This study is anchored on Rosenzweig-MacArthur equations to explore trophic behavior between Alcedinidae kingfishers (Halcyon gularis, Todiramphus chloris, Actenoides lindsayi, Alcedo atthis) and ichthyofaunal prey (Glossogobius aureus, Nomorhamphus pectoralis, Poecilia reticulata, Giuris margaritacea, Glossogobius illimis) in the lotic habitats of the Santa Barbara River, Nagcarlan, Laguna. Two scenarios were considered, namely, (i) unbounded growth under free-lunch hypothesis and (ii) resource partitioning to assess population trajectories, displacement risks, and coexistence potential. Under the first scenario arrangements of a free-lunch hypothesis, exponential prey saturation triggers Type II functional responses, yielding maximal per-capita growth rates (λ): H. gularis (1.1875), T. chloris (3.375), A. lindsayi (1.1429), A. atthis (6.2857). The second scenario anchors on resource partitioning, where predation dampens prey to ~9,500-9,800 individuals with low oscillations: H. gularis stabilizes N. pectoralis, T. chloris curbs P. reticulata, A. lindsayi tempers G. margaritacea, and polyphagous A. atthis mitigates G. aureus and G. illimis surges. Specialists (H. gularis, A. lindsayi; Type II=0.38) coexist at ~2,000-3,000 individuals. These models underscore growth asymmetries favoring high-r species (generalists) informing interventions such as habitat conservation, niche enhancement, and resource augmentation amid uncertainties of tropical upstream ecology. Keywords: niche displacement, population ecology, Alcedinidae, resource partitioning, competitive exclusion, Philippine kingfishers