Ecology of isolated open-formation Tropidurus (Reptilia: Tropiduridae) in Amazonian lowland rain forest

1993 ◽  
Vol 71 (12) ◽  
pp. 2370-2390 ◽  
Author(s):  
Laurie J. Vitt
Keyword(s):  
Life History ◽  
Tropical Forest ◽  
Clutch Size ◽  
Northeastern Brazil ◽  
Close Relative ◽  
Isolated Populations ◽  
Rock Outcrops ◽  
Lowland Tropical Forest ◽  
Life History Characteristics ◽  
Clutch Mass

Ecological, morphological, and life-history characteristics of three as yet undescribed populations of open-formation Tropidurus species in Rondônia and a population of Tropidurus oreadicus in Pará, Brazil, that are isolated on rock outcrops completely surrounded by lowland tropical forest were compared with similar characteristics of a eurytopic open-formation close relative, Tropidurus hispidus, and a crevice-adapted close relative, Tropidurus semitaeniatus, from an open-formation (caatinga) habitat in northeastern Brazil. Individuals of the isolated Amazonian populations do not enter the forest, but escape into narrow crevices on rock outcrops when disturbed. They are restricted to the only habitat patch in tropical forest similar to open-formation habitats, granitic rock outcrops. The outcrops maintain cerrado and caatinga vegetation and published paleoecological data indicate that the forested area surrounding the outcrops in Rondônia was cerrado in the recent past. Individuals in the isolated Tropidurus populations are morphologically flattened compared with T. hispidis, clutch size is reduced, and relative clutch mass is reduced, as is observed in other crevice-adapted species of lizards. Females deposit eggs under granitic cap rocks, like the flattened lizard T. semitaeniatus. The most parsimonious explanation for the set of characteristics shared by these four isolated lizard populations is that natural selection has led to an adjustment of behavior, morphology, and certain life-history characteristics in response to the high ecological risks associated with entering surrounding forest. It remains unclear whether this occurred once (which assumes a common ancestor), followed by canalizing selection, or the populations converged independently on similar morphology and ecology (which assumes different ancestors). The direction of divergence in behavior, morphology, clutch size, relative clutch mass, and nesting behavior in isolated populations of Tropidurus species remains unknown.

Clutch Mass, Offspring Mass, and Clutch Size: Body Mass Scaling and Taxonomic and Environmental Variation

2018 ◽  
pp. 68-97
Author(s):  
Douglas S. Glazier
Keyword(s):  
Life History ◽  
Body Size ◽  
Clutch Size ◽  
Body Mass ◽  
Life History Evolution ◽  
Offspring Size ◽  
Egg Mass ◽  
Mass Scaling ◽  
Scaling Relationships ◽  
Clutch Mass

In this chapter, I show how clutch mass, offspring (egg) mass, and clutch size relate to body mass among species of branchiopod, maxillipod, and malacostracan crustaceans, as well as how these important life history traits vary among major taxa and environments independently of body size. Clutch mass relates strongly and nearly isometrically to body mass, probably because of physical volumetric constraints. By contrast, egg mass and clutch size relate more weakly and curvilinearly to body mass and vary in inverse proportion to one another, thus indicating a fundamental trade-off, which occurs within many crustacean taxa as well. In general, offspring (egg) size and number and their relationships to body mass appear to be more ecologically sensitive and evolutionarily malleable than clutch mass. The body mass scaling relationships of egg mass and clutch size show much more taxonomic and ecological variation (log-log scaling slopes varying from near 0 to almost 1 among major taxa) than do those for clutch mass, a pattern also observed in other animal taxa. The curvilinear body mass scaling relationships of egg mass and number also suggest a significant, size-related shift in how natural selection affects offspring versus maternal fitness. As body size increases, selection apparently predominantly favors increases in offspring size and fitness up to an asymptote, beyond which increases in offspring number and thus maternal fitness are preferentially favored. Crustaceans not only offer excellent opportunities for furthering our general understanding of life history evolution, but also their ecological and economic importance warrants further study of the various factors affecting their reproductive success.

Slow life-history traits of a neritic predator, the bronze whaler (Carcharhinus brachyurus)

2017 ◽  
Vol 68 (3) ◽  
pp. 461 ◽  
Author(s):  
Michael Drew ◽  
Paul Rogers ◽  
Charlie Huveneers
Keyword(s):  
Life History ◽  
Growth Parameters ◽  
Isolated Populations ◽  
Life History Characteristics ◽  
Regional Estimates ◽  
Males And Females ◽  
Size At Age ◽  
Slow Growing ◽  
Best Fit ◽  
Age Estimates

Intra-species plasticity in the life-history characteristics of sharks leads to the need for regional estimates to accurately determine resilience to anthropogenic effects. The present study provides the first length-at-age, growth and maturity estimates for the bronze whaler (Carcharhinus brachyurus) from southern Australia. Age estimates were obtained from vertebral sections of 466 individuals spanning 50–308-cm total length. Maximum estimates of age for males and females were 25 and 31 years respectively. The three-parameter logistic model for females (L∞=308cm LT, k=0.15, α=742) and for males (L∞=317cm LT, k=0.13, α=782) provided the best fit to the size at age data. Males matured at a similar age (16 years), but smaller size than females (224v. 270cm LT). Growth parameters and age-at-maturity estimates were similar to those for genetically isolated C. brachyurus populations, and the sympatric dusky shark (C. obscurus). The southern Australian C. brachyurus population is long-lived, slow growing and late maturing. These growth parameters are needed to undertake demographic analyses to assess the resilience of C. brachyurus to fishing, and provide an example of a wide-ranging elasmobranch with similar life-history characteristics across isolated populations.

scholarly journals Clutch size in the small-sized lizard Eurolophosaurus nanuzae (Tropiduridae): does it vary along the geographic distribution of the species?

2011 ◽  
Vol 101 (1-2) ◽  
pp. 61-64 ◽  
Author(s):  
Conrado A. B Galdino ◽  
Monique Van Sluys
Keyword(s):  
Life History ◽  
Body Size ◽  
Clutch Size ◽  
Endemic Species ◽  
Life History Traits ◽  
Geographic Range ◽  
Southeastern Brazil ◽  
Rock Outcrop ◽  
Female Body Size ◽  
Clutch Mass

We studied life history traits of females of the lizard Eurolophosaurus nanuzae (Rodrigues, 1981), an endemic species of rock outcrop habitats in southeastern Brazil. During October 2002 and 2003 we sampled three populations in sites that encompass the meridional portion of the geographic range of the species. Clutch size varied from one to three eggs, with most females carrying two eggs. Clutch size did not vary among populations, but was correlated to female body size. Only larger females produced clutches of three eggs. Females of the small-sized E. nanuzae produce eggs as large as those of medium-sized tropidurids, thus investing a considerable amount of energy to produce clutches resulting in high values of relative clutch mass.

scholarly journals Using a simple morphometric marker to identify spatial units for abalone fishery management

2009 ◽  
Vol 66 (2) ◽  
pp. 305-314 ◽  
Author(s):  
T. Saunders ◽  
S. Mayfield ◽  
A. Hogg
Keyword(s):  
Life History ◽  
Fishery Management ◽  
Marine Invertebrates ◽  
Structured Populations ◽  
Systematic Sampling ◽  
Fine Scale ◽  
Isolated Populations ◽  
Current Management ◽  
Commercial Catch ◽  
Life History Characteristics

Abstract Saunders, T., Mayfield, S., and Hogg, A. 2009. Using a simple morphometric marker to identify spatial units for abalone fishery management. – ICES Journal of Marine Science, 66: 305–314. Managing stocks of sedentary marine invertebrates is complicated by the highly structured populations they form. Blacklip abalone (Haliotis rubra) form isolated populations with variable life-history characteristics. Many of the populations are “stunted”, attaining a lower maximum size than those in adjacent areas. To reduce the risks of overfishing and localized depletion, management units (MUs) that encompass individual populations need to be determined, then managed according to their life-history characteristics. Here, potential MUs in a South Australian abalone fishery were identified from the broad-scale, spatial distribution of stunted and “non-stunted” populations of blacklip abalone, by applying a morphometric marker to commercial shell samples. Key life-history parameters of the populations within the potential MUs were estimated using relationships between the morphometric marker and blacklip abalone biology. Data from fine-scale systematic sampling by commercial fishers were used to validate spatial patterns observed from the more broadly distributed commercial catch samples. The location, distribution, and size of potential MUs were largely inconsistent with those of current management. The locations of two MUs (in Gerloffs Bay) were consistent across the broad- and fine-scale datasets, with the fine-scale samples more informative for identifying a potential boundary between them. The disparity between these data and current management arrangements are highlighted, and approaches for modifying them are discussed. This approach is among the first to provide a practical means of more closely aligning the scales of assessment and management with biological reality for sedentary marine invertebrates.

scholarly journals Life history trait differences in isolated populations of the endangered Red-cockaded Woodpecker

2016 ◽  
Vol 24 (1) ◽  
pp. 55-68
Author(s):  
Lacey Williamson ◽  
Victoria Garcia ◽  
Jeffrey R. Walters
Keyword(s):  
North Carolina ◽  
Life History ◽  
Clutch Size ◽  
Life History Traits ◽  
Management Practices ◽  
Life History Trait ◽  
Picoides Borealis ◽  
Isolated Populations ◽  
Local Conditions ◽  
Trade Offs

Abstract Changes in life history traits can reveal adaptations to changing environments. Red-cockaded Woodpeckers (Picoides borealis) are cooperative breeders that have specific reproductive habitat needs. We examined three separate sites in the southeastern United States to see how life history traits differed among isolated populations of Red-cockaded Woodpeckers from 1980 to 2013. We examined the life history traits group size, partial brood loss, number of fledglings, lay date, clutch size, and lifespan. Traits differed among sites, suggesting that populations were adapted to local conditions and different life history trade-offs were important under different environmental conditions at each site. At the two coastal sites in Florida and North Carolina, the family group sizes, lifespans, and partial brood loss were higher when compared to the inland site in North Carolina. Clutch size and number fledged were higher at the two northernmost sites when compared to the southern site. Identifying the differences in life history traits can allow more specific and effective management practices.

Ecology of the arboreal tropidurid lizard Tropidurus (=Plica) umbra in the Amazon region

1997 ◽  
Vol 75 (11) ◽  
pp. 1876-1882 ◽  
Author(s):  
Laurie J. Vitt ◽  
Peter A. Zani ◽  
Teresa Cristina S. Avila-Pires
Keyword(s):  
Sexual Dimorphism ◽  
Tropical Forest ◽  
Clutch Size ◽  
Sexual Maturity ◽  
Prey Size ◽  
Amazon Region ◽  
Body Temperatures ◽  
Dietary Specialization ◽  
Lowland Tropical Forest

The tropidurid lizard Tropidurus umbra lives on medium-sized trees in lowland tropical forest of the Amazon region. Individuals may be active on tree trunks in sun or shade, with most activity occurring from 11:00 to 13:00. Body temperatures average 29.1 °C. The diet consists nearly exclusively of ants and there is no relationship between prey size and lizard size. Females reach sexual maturity at 79 mm snout–vent length (SVL) and males at 78 mm SVL. Although there appears to be no sexual dimorphism in SVL, males have relatively larger heads than females. Clutch size is usually two eggs and females appear to produce more than one clutch per season. Comparisons with other studied tropidurid lizards suggest that dietary specialization on ants, reduced sexual dimorphism, and reduced clutch size are derived characters.

Life history characteristics of an invasive cyprinid fish (Carassius gibelio) in Chimaditis Lake (northern Greece)

2008 ◽  
Vol 24 (2) ◽  
pp. 213-217 ◽  
Author(s):  
I. D. Leonardos ◽  
A. C. Tsikliras ◽  
V. Eleftheriou ◽  
Y. Cladas ◽  
I. Kagalou ◽  
...  
Keyword(s):  
Life History ◽  
Cyprinid Fish ◽  
Northern Greece ◽  
Carassius Gibelio ◽  
Life History Characteristics

Adaptive strategies and life history characteristics in a warming climate: Salmon in the Arctic?

2012 ◽  
Vol 96 (10-11) ◽  
pp. 1187-1226 ◽  
Author(s):  
Jennifer L. Nielsen ◽  
Gregory T. Ruggerone ◽  
Christian E. Zimmerman
Keyword(s):  
Life History ◽  
Adaptive Strategies ◽  
The Arctic ◽  
Warming Climate ◽  
Life History Characteristics
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