Nested species-rich networks of scavenging vertebrates support high levels of interspecific competition

Author(s)

Sebastian-Gonzalez, Esther ^{[1, 2]} ; Moleon, Marcos ^{[3, 4]} ; Gibert, Jean P. ^[5] ; Botella, Francisco ^[3] ; Mateo-Tomas, Patricia ^{[6, 7]} ; Olea, Pedro P. ^{[6, 8]} ; Guimaraes, Jr., Paulo R. ^[1] ; Sanchez-Zapata, Jose A. ^[3]

Affiliation

^[1] Univ Sao Paulo, Dept Ecol, BR-05508900 Sao Paulo - Brazil

^[2] Univ Hawaii, Dept Biol, Hilo, HI 96720 - USA

^[3] Univ Miguel Hernandez, Dept Biol Aplicada, Avda Univ S-N, Alicante 03202 - Spain

^[4] Univ Witwatersrand, Ctr African Ecol, Sch Anim Plant & Environm Sci, ZA-2050 Johannesburg - South Africa

^[5] Univ Nebraska, Sch Biol Sci, 410 Manter Hall, Lincoln, NE 68588 - USA

^[6] IREC CSIC UCLM JCCM, Inst Invest Recursos Cineget, Ronda Toledo S-N, Ciudad Real 17031 - Spain

^[7] Plaza Pueblos 9 1A, Leon 24900 - Spain

^[8] Univ Autonoma Madrid, Dept Ecol, Madrid 28046 - Spain

• Document type: Journal article
• Source: ECOLOGY; v. 97, n. 1, p. 95-105, JAN 2016.
• Web of Science Citations: 13

Abstract

Disentangling the processes that shape the organization of ecological assemblages and its implications for species coexistence is one of the foremost challenges of ecology. Although insightful advances have recently related community composition and structure with species coexistence in mutualistic and antagonistic networks, little is known regarding other species assemblages, such as those of scavengers exploiting carrion. Here we studied seven assemblages of scavengers feeding on ungulate carcasses in mainland Spain. We used dynamical models to investigate if community composition, species richness and structure (nestedness) affect species coexistence at carcasses. Scavenging networks showed a nested pattern in sites where highly efficient, obligate scavengers (i.e., vultures) were present and a non-nested pattern everywhere else. Griffon Vulture (Gyps fulvus) and certain meso-facultative mammalian scavengers (i.e., red fox, Vulpes vulpes, and stone marten, Martes foina) were the main species contributing to nestedness. Assemblages with vultures were also the richest ones in species. Nested species-rich assemblages with vulture presence were associated with high carcass consumption rates, indicating higher interspecific competition at the local scale. However, the proportion of species stopping the consumption of carrion (as derived from the competitive dynamic model) stabilized at high richness and nestedness levels. This suggests that high species richness and nestedness may characterize scavenging networks that are robust to high levels of interspecific competition for carrion. Some facilitative interactions driven by vultures and major facultative scavengers could be behind these observations. Our findings are relevant for understanding species' coexistence in highly competitive systems. (AU)

• FAPESP's process: 11/17968-2 - Structure and geographical variability in mutualistic networks of plants and their frugivorous birds
• Grantee: Esther Sebastián González
• Support Opportunities: Scholarships in Brazil - Post-Doctoral