Intraspecific isotopic niche variation in broad-snouted caiman (<i>Caiman latirostris</i>)

Marques, Thiago S.; Lara, Neliton R. F.; Bassetti, Luís A. B.; Piña, Carlos Ignácio; Camargo, Plínio Barbosa de; Verdade, Luciano Martins

doi:10.1080/10256016.2013.835309

Cited by 16 publications

(18 citation statements)

References 57 publications

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“…This result indicates that size-related differences in resource exploitation exist and that they should consequently reduce competition among age classes [41, 42]. These results confirm the conclusions of research on the Nile crocodile ( Crocodylis niloticus ) [41] and the broad-snouted caiman ( Caiman latirostris ) [43] and also underscore the utility of the stable isotope method for revealing dietary shifts as animals develop. Indeed, crocodilians increase considerably in body size during their lifetimes (1000x from hatchling to adult).…”

Section: Resultssupporting

confidence: 68%

“…Thus, based on what little is known about crocodilians and data obtained from other reptiles, excretion dynamics can affect discrimination factors. This research underscores that experimental data are lacking for isotope incorporation in reptiles and, more precisely, in crocodilians: since 1990, fewer than 10 stable isotope studies have been published on crocodilians, compared to the more than 400 publications available for marine mammals [29,30,41,43,51–54].…”

Section: Resultsmentioning

confidence: 87%

“…Crocodilian social behavior may result in certain individuals having limited access to certain microhabitats, restricting food resources [41,43,44]. In the dry season, Agami Pond is one of the only areas within the marsh that still holds water, resulting in a high abundance of different fish species.…”

Section: Resultsmentioning

confidence: 99%

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The dark side of the black caiman: Shedding light on species dietary ecology and movement in Agami Pond, French Guiana

Caut

François²,

Bacques³

et al. 2019

PLoS ONE

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The black caiman is one of the largest neotropical top predators, which means that it could play a structuring role within swamp ecosystems. However, because of the difficulties inherent to studying black caimans, data are sorely lacking on many aspects of their general biology, natural history, and ecology, especially in French Guiana. We conducted a detailed study of the Agami Pond black caiman population using a multidisciplinary approach. The aim was to better understand the species’ dietary ecology and movements in the pond, and thus its functional role in pond system. We gathered natural history data, tracked caiman movements using satellite transmitters, and characterized feeding ecology via stable isotope analysis. Our study was carried out over three sampling periods and spanned both wet and dry seasons, which differ in their hydrological and ecological conditions. Our results show that black caiman abundance and age demographics differed between seasons in Agami Pond. In the dry season, Agami Pond is one of the only areas within the marsh to hold water. It thus contains large quantities of different fish species, which form the basis of the black caiman’s diet. Caiman body size, a proxy for age class, was around 1.5 meters. During the wet season, which corresponds to the breeding period for migratory birds (e.g., Agami herons), adult black caimans are present in Agami Pond. Adults were most abundant in the inundated forest. There, most individuals measured up to 2 meters. They also exhibited a particular “predatory” behavior near bird nests, preying on fallen chicks and adults. Juveniles and subadults were present during both seasons in the pond’s open waters. These behavioral observations were backed up by stable isotope analysis, which revealed ontogenetic variation in the caiman’s isotopic values. This isotopic variation reflected variation in diet that likely reduced intraspecific competition between adults and young. The telemetry and microchip data show that different age classes had different movement patterns and that seasonal variation in the pond may influence caiman prey availability and reproductive behavior. The new information gathered should help predict this species’ responses to potential ecosystem disturbance (e.g., water pollution, habitat destruction) and inform the development of an effective conservation plan that involves locals and wildlife officials.

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Section: Resultssupporting

confidence: 68%

Section: Resultsmentioning

confidence: 87%

See 1 more Smart Citation

The dark side of the black caiman: Shedding light on species dietary ecology and movement in Agami Pond, French Guiana

Caut

François²,

Bacques³

et al. 2019

PLoS ONE

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“…; Marques et al . ). By combining stable isotope analysis with movement data, American alligators ( Alligator mississippiensis ) were found to exhibit spatially structured diets (Rosenblatt & Heithaus ), with individuals inhabiting downstream areas feeding (partially) from marine food webs.…”

Section: Introductionmentioning

confidence: 97%

Feeding across the food web: The interaction between diet, movement and body size in estuarine crocodiles (Crocodylus porosus)

et al. 2014

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The estuarine crocodile (Crocodylus porosus) is an apex predator across freshwater, estuarine and coastal environments. The impact of a changing C. porosus population upon the ecosystem is unknown, but due to large ontogenetic changes in body mass (>1000-fold) their impact may be wide reaching and substantial. Here we investigated the relationship between diet, movement and body size in a population of C. porosus inhabiting a tidal river in northern Australia. Subcutaneous acoustic transmitters and fixed underwater receivers were used to determine the activity space and movement patterns of 42 individuals (202-451 cm in total length). There was no size-related spatial partitioning among different sized crocodiles. Large individuals (snout-vent length (SVL): 160 cm < SVL < 188.5 cm) did, however, exhibit a much larger activity space than other size classes. Diet and individual specialization was assessed using the composition of stable carbon (δ 13 C) and nitrogen (δ 15 N) isotopes in tissues with different turnover rates. There was a quadratic relationship between body size and δ 15 N, suggesting that medium-sized individuals (110 cm < SVL < 160 cm) incorporated a greater proportion of high trophic prey into their diets than small (SVL < 110 cm) or large individuals (SVL > 160 cm). Tissue δ 13 C composition on the other hand was positively correlated with body size, indicating that different size classes were trophically linked to primary producers in different habitats. Individual-level analyses showed that small crocodiles were generalist feeders while medium and large size classes specialized on particular prey items within the food webs they fed. The findings further our understanding of ontogenetic variation in C. porosus diet, and suggest that change in C. porosus population size or demographics may be influential at various levels across the local food web.

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“…Resource partitioning within species is a strategy used by reptiles to maximize coexistence among individuals (e.g. Marques et al 2013a, Richards-Dimitrie et al 2013. Species exhibiting sexual size dimorphism may have sexual differences in nutritional requirements, which can result in the use of different resources (Wearmouth and Sims 2008).…”

Section: Introductionmentioning

confidence: 99%

The trophic niche of Mesoclemmys vanderhaegei (Testudines: Chelidae): evidence from stable isotopes

et al. 2017

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Intraspecific isotopic niche variation in broad-snouted caiman (Caiman latirostris)

Cited by 16 publications

References 57 publications

The dark side of the black caiman: Shedding light on species dietary ecology and movement in Agami Pond, French Guiana

The dark side of the black caiman: Shedding light on species dietary ecology and movement in Agami Pond, French Guiana

Feeding across the food web: The interaction between diet, movement and body size in estuarine crocodiles (Crocodylus porosus)

The trophic niche of Mesoclemmys vanderhaegei (Testudines: Chelidae): evidence from stable isotopes

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