Relationships between rainfall, nesting habitat and fecundity of<i>Caiman crocodilus yacare</i>in the Pantanal, Brazil

Campos, Zilca; Magnusson, William E.

doi:10.1017/s0266467400008828

Cited by 23 publications

(17 citation statements)

References 11 publications

(12 reference statements)

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“…Previous studies did not detect this relationship measuring egg volume in C. latirostris and in a related species (Caiman yacare; Campos and Magnusson 1995). Larriera et al (2004) did not find a significant relationship between clutch size and egg mass after removing female BM or SVL effects.…”

Section: Discussionmentioning

confidence: 69%

The relationship between nesting habitat and hatching success in Caiman latirostris (Crocodylia, Alligatoridae)

Montini¹,

Piña

Larriera

et al. 2006

Phyllomedusa

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The relationship between nesting habitat and hatching success in Caiman latirostris (Crocodylia, Alligatoridae). The Broad-snouted Caiman uses different habitats for nesting; it has temperature-dependent sex determination (TSD) and nesting habitat selection by females could affect sex and other hatchlings characteristics. Here we evaluated reproductive parameters in three nesting habitats: forest, savanna, and floating vegetation. We collected 154 caiman nests during the summer of 2001-2002. Since natural incubation could mask possible clutch-effects, eggs were collected soon after oviposition and artificially incubated. We found that eggs laid in the forest were wider than those laid in savanna, hatching success varied, decreasing from floating vegetation to forest. As egg width is positively correlated to female body size, the present results suggest that female body size could be related to nesting habitat use in Caiman latirostris. However, there were no differences in hatchling size among nesting habitats.

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Section: Discussionmentioning

confidence: 69%

The relationship between nesting habitat and hatching success in Caiman latirostris (Crocodylia, Alligatoridae)

Montini¹,

Piña

Larriera

et al. 2006

Phyllomedusa

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“…The reproductive cycle is related to the cycle of abdominal fat, and conditioned by variations in rainfall and flooding levels [Thorbjarnarson, 1994]. For C. c. yacare, the rains, and therefore water levels have also been related to nesting, egg survival, sex ratio of hatchings, and fertility [Campos, 1993;Campos and Magnusson, 1995].…”

Section: Introductionmentioning

confidence: 99%

Annual reproductive activity of Caiman crocodilus fuscus in captivity

et al. 2003

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We describe the gonadal and abdominal fat storage cycles for a population of Caiman crocodilus fuscus kept in captivity at a breeding farm. The reproductive cycles of males and females are clearly seasonal. Vitellogenic follicles were observed in females year-round; however, the follicular growth that produces the preovulatory follicles for the breeding season occurs in November-May (most of the dry season to the beginning of the rainy season). These months correspond with the presence of physiologically reproductive males. Oviposition takes place during the wet season (April-August) and the births occur at the end of this season (September-November). Fat storage was not related to reproductive activity, and did not vary by month or between sexes. Although environmental and hormonal conditions have been improved for these captive animals, they maintain a strongly seasonal reproductive cycle, historically fixed to oviposit in the most favorable period for nest construction and hatching during the rainy season.

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“…This type of change in the ecosystem may affect directly the number of jabiru nests in the floodplain, given the strong relationship between water availability, flood regime and nesting by the jabiru stork. It is not unlikely that other animal species that are highly dependent on the floods, such as the yacare caiman (CAMPOS & MAGNUSSON 1995) or the endangered marsh deer (TOMAS et al 2001) would be negatively affected by such a large-scale environmental change.…”

Section: Discussionmentioning

confidence: 99%

How much can the number of jabiru stork (Ciconiidae) nests vary due to change of flood extension in a large Neotropical floodplain?

Mourão¹,

Tomás²,

Campos³

2010

Zoologia (Curitiba, Impr.)

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The jabiru stork, Jabiru mycteria (Lichtenstein, 1819), a large, long-legged wading bird occurring in lowland wetlands from southern Mexico to northern Argentina, is considered endangered in a large portion of its distribution range. We conducted aerial surveys to estimate the number of jabiru active nests in the Brazilian Pantanal (140,000 km²) in September of 1991-1993, 1998, 2000-2002, and 2004. Corrected densities of active nests were regressed against the annual hydrologic index (AHI), an index of flood extension in the Pantanal based on the water level of the Paraguay River. Annual nest density was a non-linear function of the AHI, modeled by the equation 6.5 · 10-8 · AHI1.99 (corrected r² = 0.72, n = 7). We applied this model to the AHI between 1900 and 2004. The results indicate that the number of jabiru nests may have varied from about 220 in 1971 to more than 23,000 in the nesting season of 1921, and the estimates for our study period (1991 to 2004) averaged about 12,400 nests. Our model indicates that the inter-annual variations in flooding extent can determine dramatic changes in the number of active jabiru nests. Since the jabiru stork responds negatively to drier conditions in the Pantanal, direct human-induced changes in the hydrological patterns, as well as the effects of global climate change, may strongly jeopardize the population in the region

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Relationships between rainfall, nesting habitat and fecundity ofCaiman crocodilus yacarein the Pantanal, Brazil

Cited by 23 publications

References 11 publications

The relationship between nesting habitat and hatching success in Caiman latirostris (Crocodylia, Alligatoridae)

The relationship between nesting habitat and hatching success in Caiman latirostris (Crocodylia, Alligatoridae)

Annual reproductive activity of Caiman crocodilus fuscus in captivity

How much can the number of jabiru stork (Ciconiidae) nests vary due to change of flood extension in a large Neotropical floodplain?

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