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.

Ecology of the lizard Kentropyx pelviceps (Sauria: Teiidae) in lowland rain forest of Ecuador

1995 ◽  
Vol 73 (4) ◽  
pp. 691-703 ◽  
Author(s):  
Laurie J. Vitt ◽  
Peter A. Zani ◽  
Janalee P. Caldwell ◽  
Edwin O. Carrillo
Keyword(s):  
Clutch Size ◽  
Morphological Characteristics ◽  
Maximum Size ◽  
Female Size ◽  
Body Temperatures ◽  
Lowland Rain Forest ◽  
Lowland Tropical Forest ◽  
Treefall Gaps ◽  
Direct Exposure ◽  
Males And Females

Kentropyx pelviceps was studied in lowland tropical forest of eastern Ecuador. Most individuals were first observed in leaf litter of treefall gaps or forest, approximately 30% being first observed above ground on trunks or branches of fallen trees. Activity occurred from 10:00 to 16:00 in microhabitats receiving maximum insolation. Body temperatures of active lizards averaged 34.1 ± 0.4 °C. Lizards active when sun was available had higher body temperatures than lizards active when sun was not available. When sun was available, lizards spent more time moving and moved farther than when sun was not available. When sun was hidden behind clouds, lizards typically ceased foraging, pressed their bodies against the substrate, and basked, receiving direct exposure. Most time active was allocated to basking, presumably as a result of limited availability of sunlight. Prey consisted primarily of roaches, orthopterans, and spiders, and prey size was determined to a large extent (69.6% of variation) by lizard body size. Males and females reached sexual maturity at 80 mm snout–vent length. Males reached a larger maximum size than females, and sexual dimorphism was apparent in nearly all morphological characteristics of adults when the effect of size was removed. Clutch size averaged 6.5 ± 0.3 eggs, and there was no relationship between clutch size and female size. Evidence suggests that the breeding season is extended. Comparisons with other studied species of Kentropyx suggest that many aspects of the ecology of K. pelviceps in eastern Ecuador are affected by the reduced time available for activity resulting from reduced sun availability.

Life in the trees: the ecology and life history of Kentropyx striatus (Teiidae) in the lavrado area of Roraima, Brazil, with comments on the life histories of tropical teiid lizards

1992 ◽  
Vol 70 (10) ◽  
pp. 1995-2006 ◽  
Author(s):  
Laurie J. Vitt ◽  
Celso Morato de Carvalho
Keyword(s):  
Life History ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Prey Size ◽  
Annual Rainfall ◽  
Activity Period ◽  
Body Temperatures ◽  
Wet Season ◽  
Reproductive Characteristics ◽  
History Of

The ecology and life history of the tropical teiid lizard Kentropyx striatus were studied in a grassland of northern Brazil, the lavrado area. The area, located nearly at the equator, experiences a prolonged dry season with a wet season extending from May to September. Total annual rainfall averages 1750 mm. Lizards were nonrandomly distributed among habitat patches and microhabitats. Most individuals were in trees and shrubs surrounding temporary and permanent water. Most individuals were observed active during late morning, the time period during which feeding and social interactions were observed. Lizards bask to achieve active body temperatures averaging 35.7 ± 0.23 °C. Body temperature is correlated with both substrate and air temperatures; foraging lizards maintained higher temperatures than basking lizards regardless of whether they were in sun, and lizards sampled when there was cloud cover had lower body temperatures than those sampled when sun was available. Females reach sexual maturity at 74 mm snout–vent length (SVL), produce 3–9 eggs per clutch, reproduce more than once per season, and commence reproduction during the wet season. Lizards hatch from eggs at 31 mm SVL. Maturity appears to be reached in 1 year or less. Overall, female reproductive characteristics are similar to those of other tropical teiid lizards that have been studied, with body size explaining much of the variance in reproductive characteristics across species. There is pronounced sexual dimorphism, with males larger in body size as well as certain other characteristics independent of body size. Sexual dimorphism appears to be a consequence of sexual selection. The diet is varied, but is dominated volumetrically by frogs, eruciform larvae, and spiders. Lizard body size accounted for only 5.5% of the variance in prey size and there was no difference in prey size due to sex. The occurrence of frogs and lizards in K. striatus stomachs suggests that teiid lizards may influence the structure of lizard and frog assemblages. The similarity of K. striatus to other studied tropical teiids in reproductive characteristics, morphology, activity period, activity temperatures, and diet underscore the conservative nature of the ecology of teiid lizards, presumably a consequence of their mode of prey acquisition.

Geographical ecology of the gymnophthalmid lizard Neusticurus ecpleopus in the Amazon rain forest

1998 ◽  
Vol 76 (9) ◽  
pp. 1671-1680 ◽  
Author(s):  
Laurie J Vitt ◽  
Peter A Zani ◽  
Teresa Cristina Avila-Pires ◽  
Maria Cristina Espósito
Keyword(s):  
Prey Size ◽  
Size Variation ◽  
Morphological Characteristics ◽  
Prey Type ◽  
Morphological Characters ◽  
Microhabitat Use ◽  
Body Temperatures ◽  
Lowland Tropical Forest ◽  
Amazon Rain Forest ◽  
Substrate Temperatures

Lizards in four distantly separated populations of the gymnophthalmid lizard Neusticurus ecpleopus in the Amazon region of South America were strikingly specific in habitat and microhabitat use, being restricted to streams and swamps and living between the water line and the bank-forest interface. They were as likely to be active during cloudy periods as during sunny periods, but most individuals were not exposed to direct insolation while active. Activity occurred through much of the day, with most activity at two sites during between 11:00 and 14:30. Body temperatures were 27.0 ± 0.02°C and were correlated with substrate temperatures. Body temperatures were higher than substrate temperatures, indicating behavioral or possibly physiological thermoregulation. These lizards ate a variety of prey, but eight prey categories accounted for a major proportion of the total diet at all sites. There were differences among sites in prey type, prey size, relative prey size, and total stomach fullness. Even though there was some size variation among sites, variation in other morphological characters was more striking. Even withstanding the differences among populations in ecological and morphological characteristics, it appears that much of the ecology of N. ecpleopus is constrained by fidelity to specific habitat patches (stream banks) distributed linearly through lowland tropical forest.

Ecology of the lizard Norops oxylophus (Polychrotidae) in lowland forest of southeastern Nicaragua

1995 ◽  
Vol 73 (10) ◽  
pp. 1918-1927 ◽  
Author(s):  
Laurie J. Vitt ◽  
Peter A. Zani ◽  
Richard D. Durtsche
Keyword(s):  
Sexual Maturity ◽  
Sexual Difference ◽  
Prey Size ◽  
Body Temperatures ◽  
Lowland Forest ◽  
Rapid Succession ◽  
Ecological Characteristics ◽  
Ecological Success ◽  
Rate Of Movement

The lizard Norops oxylophus used a variety of microhabitats distributed linearly along streams in southeastern Nicaragua. Body temperatures averaged 27.8 °C and lizards typically were in shade. Lizards spent 98.16% of their time stationary and 1.84% moving. The rate of movement was low (0.001 m∙s−1) even when corrected for time not moving (0.071 m∙s−1). Caterpillars, spiders, ants, and various orthopterans composed most of the diet. Prey size was only weakly correlated with lizard snout–vent length (SVL) and there was no sexual difference in prey size independent of SVL. Lizards averaged 0.01 prey attacks/min and most lizards spent less than 0.15% of their time feeding. Males were larger than females, but females had a relatively larger body and greater mass. Females reach sexual maturity at 49 mm SVL and produce clutches of a single egg in rapid succession. Males reach sexual maturity at 53 mm SVL. Many ecological characteristics of N. oxylophus reflect a set of characteristics evolving early in the N. fuscoauratus series of the anoline lineage that has contributed to their ecological success in stream habitats of Caribbean lowland forest.

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.

scholarly journals Reproductive Cycle, Size and Age at Sexual Maturity, and Sexual Dimorphism in the Stream-Breeding Frog Crossodactylus schmidti (Hylodidae)

2019 ◽  
Vol 14 (1) ◽  
pp. 1 ◽  
Author(s):  
Vinícius Matheus Caldart ◽  
Luiza Loebens ◽  
Amanda Jamile Carvalho Brum ◽  
Lívia Bataioli ◽  
Sonia Zanini Cechin
Keyword(s):  
Sexual Dimorphism ◽  
Reproductive Cycle ◽  
Sexual Maturity

scholarly journals Monitoring Vegetation Change in the Presence of High Cloud Cover with Sentinel-2 in a Lowland Tropical Forest Region in Brazil

2020 ◽  
Vol 12 (11) ◽  
pp. 1829
Author(s):  
Tatiana Nazarova ◽  
Pascal Martin ◽  
Gregory Giuliani
Keyword(s):  
Tropical Forest ◽  
Temporal Resolution ◽  
Cloud Cover ◽  
Detection System ◽  
Forest Degradation ◽  
High Cloud ◽  
Lowland Tropical Forest ◽  
Forest Region ◽  
Vegetation Loss ◽  
Sentinel 2

Forests play major roles in climate regulation, ecosystem services, carbon storage, biodiversity, terrain stabilization, and water retention, as well as in the economy of numerous countries. Nevertheless, deforestation and forest degradation are rampant in many parts of the world. In particular, the Amazonian rainforest faces the constant threats posed by logging, mining, and burning for agricultural expansion. In Brazil, the “Sete de Setembro Indigenous Land”, a protected area located in a lowland tropical forest region at the border between the Mato Grosso and Rondônia states, is subject to illegal deforestation and therefore necessitates effective vegetation monitoring tools. Optical satellite imagery, while extensively used for landcover assessment and monitoring, is vulnerable to high cloud cover percentages, as these can preclude analysis and strongly limit the temporal resolution. We propose a cloud computing-based coupled detection strategy using (i) cloud and cloud shadow/vegetation detection systems with Sentinel-2 data analyzed on the Google Earth Engine with deep neural network classification models, with (ii) a classification error correction and vegetation loss and gain analysis tool that dynamically compares and updates the classification in a time series. The initial results demonstrate that such a detection system can constitute a powerful monitoring tool to assist in the prevention, early warning, and assessment of deforestation and forest degradation in cloudy tropical regions. Owing to the integrated cloud detection system, the temporal resolution is significantly improved. The limitations of the model in its present state include classification issues during the forest fire period, and a lack of distinction between natural vegetation loss and anthropogenic deforestation. Two possible solutions to the latter problem are proposed, namely, the mapping of known agricultural and bare areas and its subsequent removal from the analyzed data, or the inclusion of radar data, which would allow a large amount of finetuning of the detection processes.

scholarly journals Tropical forest soil carbon stocks do not increase despite 15 years of doubled litter inputs

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Emma J. Sayer ◽  
Luis Lopez-Sangil ◽  
John A. Crawford ◽  
Laëtitia M. Bréchet ◽  
Ali J. Birkett ◽  
...  
Keyword(s):  
Organic Matter ◽  
Tropical Forest ◽  
Critical Role ◽  
Tropical Soils ◽  
Soil Geochemistry ◽  
Soil Minerals ◽  
Litter Addition ◽  
Lowland Tropical Forest ◽  
Tropical Forest Soil ◽  
Underlying Mechanisms

AbstractSoil organic carbon (SOC) dynamics represent a persisting uncertainty in our understanding of the global carbon cycle. SOC storage is strongly linked to plant inputs via the formation of soil organic matter, but soil geochemistry also plays a critical role. In tropical soils with rapid SOC turnover, the association of organic matter with soil minerals is particularly important for stabilising SOC but projected increases in tropical forest productivity could trigger feedbacks that stimulate the release of stored SOC. Here, we demonstrate limited additional SOC storage after 13–15 years of experimentally doubled aboveground litter inputs in a lowland tropical forest. We combined biological, physical, and chemical methods to characterise SOC along a gradient of bioavailability. After 13 years of monthly litter addition treatments, most of the additional SOC was readily bioavailable and we observed no increase in mineral-associated SOC. Importantly, SOC with weak association to soil minerals declined in response to long-term litter addition, suggesting that increased plant inputs could modify the formation of organo-mineral complexes in tropical soils. Hence, we demonstrate the limited capacity of tropical soils to sequester additional C inputs and provide insights into potential underlying mechanisms.

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