Diet and trophic niche overlap among a native waterbird and two non-native herbivores in Pampas grasslands

Fernandez, Cínthia Negrine; Robe, Lizandra Jaqueline; Bugoni, Leandro

doi:10.1016/j.fooweb.2021.e00201

Cited by 3 publications

(3 citation statements)

References 59 publications

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“…Niche partitioning reduces interspecific competition, allowing for the sympatric coexistence of two species with similar ecological niches (Hardin, 1960; Schoener, 1974). Understanding how closely related species overlap or differentiate their diets and habitat use can aid in their management (Fernandez et al, 2021). The federally listed southern Distinct Population Segment (sDPS) of green sturgeon, Acipenser medirostris , and the California State Species of Special Concern, white sturgeon, Acipenser transmontanus , are two closely related sister taxa that live sympatrically in the San Francisco estuary (SFE) system.…”

Section: Introductionmentioning

confidence: 99%

Comparative stable isotope analyses of green sturgeon (Acipenser medirostris) and white sturgeon (A. transmontanus) in the San Francisco estuary

Miller,

Singer,

Peterson

et al. 2023

Journal of Fish Biology

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Green Sturgeon (Acipenser medirostris) and White Sturgeon (A. transmontanus) are closely related, sympatric species that inhabit the San Francisco Estuary. Green Sturgeon have a more marine life history but both species spawn in the Sacramento River and reside for some duration in the San Francisco Bay. These sturgeons are of conservation concern, yet little is known about their dietary competition when they overlap in space and time. To examine evidence of dietary differentiation, we collected whole blood and blood plasma from 26 Green Sturgeon and 35 White Sturgeon in the San Francisco Bay. Using carbon and nitrogen stable isotope analyses, we compared their relative trophic levels and foraging locations along the freshwater to marine gradient. Sampling blood plasma and whole blood allowed comparison of dietary integration over shorter and longer time scales, respectively. Plasma and whole blood δ13C values confirmed Green Sturgeon had more marine dietary sources than White Sturgeon. Plasma δ15N values revealed White Sturgeon fed at lower trophic levels than Green Sturgeon recently, however, whole blood δ15N values demonstrated the two species fed at the same trophic level over longer time scales. Larger individuals of both species had higher δ13C values than smaller individuals, reflecting more marine food sources in adulthood. Length did not affect δ15N values of either species. Isotope analyses supported the more marine life history of Green than White Sturgeon and potentially highlight a temporary trophic differentiation of diet between species during and preceding the overlapping life stage in the San Francisco Bay.This article is protected by copyright. All rights reserved.

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Section: Introductionmentioning

confidence: 99%

Comparative stable isotope analyses of green sturgeon (Acipenser medirostris) and white sturgeon (A. transmontanus) in the San Francisco estuary

Miller,

Singer,

Peterson

et al. 2023

Journal of Fish Biology

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“…Some studies consider dietary and habitat overlap between livestock and wildlife as a proof that there is competition between them (Butt & Turner, 2012;Chaikina & Ruckstuhl, 2006;Fernandez et al, 2021;Koetke et al, 2020). Although they are important in expressing the competition between livestock and wildlife, they do not give the concrete proof that when they occur there is competition (Butt & Turner, 2012).…”

Section: Views On the Impact Of Wildlife Livestock Interactionsmentioning

confidence: 99%

“…One-way ANOVA was used to compare the mean difference of species consumed by both animals across the three periods. The calculated mean of the species consumed by buffalo and livestock was used to plot bipartite ecological networks and portray the extent to which foraging resources are shared between buffalo and livestock in MKGR (Fernandez et al, 2021;Pansu et al, 2019) using the R function (plotweb).…”

Section: (Iv) Data Analysesmentioning

confidence: 99%

Impact of illegal livestock grazing on the socio-ecologica role of trophy hunting: the case of Moyowosi Kigosi game reserve, Tanzania

Musika

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Tanzania has set aside almost 40% of its land for conservation and trophy hunting is the main activity conducted in an area covering about 80% of Tanzania’s conserved land. Trophy hunting conserves wildlife inside and outside Protected Areas (PAs) and provides socio-economic incentives for communities to conserve wildlife. Despite its importance, hunting companies surrendered 45% of Tanzania’s hunting blocks to the government mainly due to habitat destruction mediated by illegal livestock grazing. Unfortunately, there is no empirical information on how illegal grazing affects trophy hunting. Therefore, the impact of illegal grazing on the socio-ecological role of trophy hunting was examined using Moyowosi - Kigosi Game Reserve (MKGR) as a case study. The study investigated whether the physical presence of trophy hunting deters illegal grazing, improves wildlife habitats, and diversifies rural income. Field experiments, laboratory work, questionnaires, and official records from MKGR were used in this study. The study revealed that illegal grazing persisted in MKGR over three decades (1990 – 2019). It destructed wildlife habitats, reduced forages, enhanced soil compaction, increased human activities in the hunting blocks, and caused hunting blocks to lose their economic viability. Also, there is a higher dietary overlap between buffalo and livestock, buffalo density decreased in invaded areas and buffalo deployed spatial partitioning of about 5 km to avoid livestock. The study confirmed that indeed, trophy hunting plays an important socio-ecological role within and outside protected areas. If affected, it will compromise the multiple socio-economic benefits often gained by the local communities. The ecological role of trophy hunting in conserving grass biomass and cover, enhancing soil infiltration and penetration by preventing illegal grazing as observed in operational hunting blocks is also apparent. The study recommends the MKGR address illegal grazing at the hotspot areas and should conduct studies on areas outside the reserve that could be re-seeded with grass species preferred by herders. The MKGR should establish awareness campaigns on the impact of illegal grazing and develop a restoration plan to enhance soil nutrients, support herbaceous cover, and diversify wildlife species to boost ecosystem functioning and prevent further deterioration of this globally important Ramsar site in Tanzania.

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Herbivore species coexistence in changing rangeland ecosystems: First high resolution national open-source and open-access ensemble models for Iceland

Boulanger-Lapointe

Ágústsdóttir

Barrio

et al. 2022

Science of The Total Environment

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Diet and trophic niche overlap among a native waterbird and two non-native herbivores in Pampas grasslands

Cited by 3 publications

References 59 publications

Comparative stable isotope analyses of green sturgeon (Acipenser medirostris) and white sturgeon (A. transmontanus) in the San Francisco estuary

Comparative stable isotope analyses of green sturgeon (Acipenser medirostris) and white sturgeon (A. transmontanus) in the San Francisco estuary

Impact of illegal livestock grazing on the socio-ecologica role of trophy hunting: the case of Moyowosi Kigosi game reserve, Tanzania

Herbivore species coexistence in changing rangeland ecosystems: First high resolution national open-source and open-access ensemble models for Iceland

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