scholarly journals Trophic ecology and foraging behavior of Tropidurus hispidus and Tropidurus semitaeniatus (Squamata, Tropiduridae) in a caatinga area of northeastern Brazil

2011 ◽  
Vol 101 (3) ◽  
pp. 225-232 ◽  
Author(s):  
Leonardo B. Ribeiro ◽  
Eliza M. X. Freire
Keyword(s):  
Foraging Behavior ◽  
Diet Composition ◽  
Trophic Ecology ◽  
Dry Season ◽  
Northeastern Brazil ◽  
Wet Season ◽  
Lizard Species ◽  
Important Prey ◽  
Lepidopteran Larvae ◽  
Prey Items

This study aimed to analyze the seasonal variation in diet composition and foraging behavior of Tropidurus hispidus (Spix, 1825) and T. semitaeniatus (Spix, 1825), as well as measurement of the foraging intensity (number of moves, time spent stationary, distance traveled and number of attacks on prey items) in a caatinga patch on the state of Rio Grande do Norte, Brazil. Hymenoptera/Formicidae and Isoptera predominated in the diet of both species during the dry season. Opportunistic predation on lepidopteran larvae, coleopteran larvae and adults, and orthopteran nymphs and adults occurred in the wet season; however, hymenopterans/Formicidae were the most important prey items. The number of food items was similar between lizard species in both seasons; however the overlap for number of prey was smaller in the wet season. Preys ingested by T. hispidus during the wet season were also larger than those consumed by T. semitaeniatus. Seasonal comparisons of foraging intensity between the two species differed, mainly in the wet season, when T. hispidus exhibited less movement and fewer attacks on prey, and more time spent stationary if compared to T. semitaeniatus. Although both lizards are sit-and-wait foragers, T. semitaeniatus is more active than T. hispidus. The diet and foraging behavior of T. hispidus and T. semitaeniatus overlap under limiting conditions during the dry season, and are segregative factors that may contribute to the coexistence of these species in the wet season.

Trophic ecology of large pelagic fish in the Saint Peter and Saint Paul Archipelago, Brazil

2019 ◽  
Vol 70 (10) ◽  
pp. 1402 ◽  
Author(s):  
F. V. Albuquerque ◽  
A. F. Navia ◽  
T. Vaske ◽  
O. Crespo ◽  
F. H. V. Hazin
Keyword(s):  
Trophic Ecology ◽  
Feeding Habits ◽  
Saint Paul ◽  
Pelagic Fish ◽  
Trophic Niche ◽  
Trophic Relationships ◽  
Main Prey ◽  
Important Prey ◽  
Saint Peter ◽  
Prey Items

Trophic relationships of large pelagic predators can determine the structure and dynamics of oceanic food webs. The feeding habits and trophic ecology of five large pelagic fish (Acanthocybium solandri, Coryphaena hippurus, Elagatis bipinnulata, Thunnus albacares and Thunnus atlanticus) in the Saint Peter and Saint Paul Archipelago were evaluated to determine whether there is a trophic-niche overlap or resource partitioning among them. Eighty prey items found in 1528 stomachs were identified and grouped into Cephalopoda, Cnidaria, Crustacea, Gastropoda, Teleostei and Tunicata. Exocoetidae and Scombridae were the main prey in the diet of Acanthocybium solandri. In C. hippurus, Cheilopogon cyanopterus and Exocoetus volitans were the most important prey items, whereas C. cyanopterus was the main prey for T. albacares. Thunnus atlanticus consumed a great proportion of invertebrate species, with shrimps of Sergestidae family being particularly important. The gastropod Cavolinia sp. was the most important prey for E. bipinnulata. The five species had a high trophic specialisation and a high trophic level (>4.4), whereas most dietary overlaps were consistently low. The most important factor for diet dissimilarity was the consumption of Exocoetidade. All species were classified as top predators with varied diets, indicating their structural and functional importance in the food web of the Archipelago.

Population diet variation and individual specialization in the poison toad, Melanophryniscus rubriventris (Vellard, 1947)

2011 ◽  
Vol 32 (2) ◽  
pp. 261-265 ◽  
Author(s):  
María Fernanda Quiroga ◽  
Marcos Vaira ◽  
Maria Ines Bonansea
Keyword(s):  
Entire Range ◽  
Diet Composition ◽  
Foraging Strategies ◽  
Future Research ◽  
Individual Specialization ◽  
Generalist Species ◽  
Defensive Strategies ◽  
Important Prey ◽  
Diet Variation ◽  
Prey Items

AbstractFew studies have investigated the level of individual variation in diet composition of poisonous frogs and toads. We compare the diet composition of three populations of a poisonous toad, Melanophryniscus rubriventris, and predicted that toads within a population might be constrained to forage on particular types of alkaloid-containing prey and consequently diets among populations might not diverge from each other. Most important prey categories in the diets of the three populations consisted of the same ground-dwelling arthropods. We found evidence for individuals consuming different arrays of prey types in all populations implying that this “generalist” species is actually comprised of individuals eating different sets of the available range of prey. Formicidae, Acari, and Coleoptera were all important alkaloid-containing prey items in the diets of all populations and individuals, although there were differences in their order of importance among populations and individuals use different sets of the entire range of alkaloid-containing preys. Future research should evaluate individual diet variation in other poisonous anurans taxa given that shifts in diet composition might have important implications for understanding the consequences of alternate foraging strategies in the evolution of defensive strategies among species.

scholarly journals Zooplankton community of Parnaíba River, Northeastern Brazil

2015 ◽  
Vol 27 (1) ◽  
pp. 118-129 ◽  
Author(s):  
Ludmilla Cavalcanti Antunes Lucena ◽  
Thaís Xavier de Melo ◽  
Elvio Sergio Figueredo Medeiros
Keyword(s):  
Water Management ◽  
Biodiversity Conservation ◽  
Zooplankton Community ◽  
River System ◽  
Dry Season ◽  
Large Rivers ◽  
Northeastern Brazil ◽  
Wet Season ◽  
Marginal Areas ◽  
River Diversions

Aim:The objective of the present work is to present a list of species of zooplankton (Rotifera, Cladocera and Copepoda) from the Parnaíba River. Additionally, we provide comments on their distribution along the river, and between dry and wet seasons.MethodsZooplankton was collected with a plankton net (60 µm mesh) and concentrated into a volume of 80 mL for further analysis, during the dry (October 2010) and wet (April 2011) seasons. Sampling was restricted to the marginal areas at depths between 80 and 150 cm.ResultsA total of 132 species was recorded among the three zooplankton groups studied. During the dry season a total of 82 species was registered and 102 species was registered for the wet season. Rotifera contributed with 66.7% of the species, followed by Cladocera (26.5%) and Copepoda (6.8%).ConclusionsThe richness of species observed was high compared to other large rivers in Brazil. In the context of current policies for water management and river diversions in northeastern Brazil, the present study highlights the importance of this river system for biodiversity conservation.

scholarly journals Patterns of Fish Assemblage, Growth, and Diet Composition in a Tropical River between Two Cascading Hydropower Dams

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Lee Nyanti ◽  
Chen-Lin Soo ◽  
Afina-Yian Chundi ◽  
Elsa-Cordelia-Durie Lambat ◽  
Alvinna Tram ◽  
...  
Keyword(s):  
Fish Species ◽  
Diet Composition ◽  
Fish Assemblages ◽  
Condition Factor ◽  
Dry Season ◽  
Growth Patterns ◽  
Native Fish ◽  
Wet Season ◽  
Fish Samples ◽  
The Impact

Construction of cascade dams has been shown to have impacts on fish assemblages and biodiversity. Yet, there is no literature on fish assemblages in the Murum River that connects the cascading Bakun and Murum dams in Sarawak, Malaysia. Hence, study on this modified ecosystem is necessitated to better understand the effects of the cascade dam construction on fish fauna. For this, fish samples were caught at five stations located along the river during both dry and wet seasons. Environmental parameters were taken concurrently with fish sampling. Length-weight relationship, condition factors, and diet composition of selected fish species in the river were also determined. The present study demonstrated that there are indications of the impact of cascading dams on the formation of a complex ecosystem in the Murum River, that is, changing from the shallow downstream of the Murum Dam to the deep transitional and inundated zone of the Bakun reservoir. The transitional zone in the Murum River exhibited the lowest fish species diversity, richness, and evenness during the dry season due to low pH and DO coupled with high turbidity. The biological indices improved when the water quality improved during the wet season. On the contrary, the diversity and evenness indices at the inundated tributary station decreased remarkably during the wet season, likely due to the migration of fish during the onset of the rainy season. This study showed that Barbonymus schwanenfeldii has a wider feeding habit which contributes to its higher distribution and abundance in the Murum River. The growth patterns of B. schwanenfeldii, Cyclocheilichthys apogon, Hampala macrolepidota, Lobocheilos ovalis, and Osteochilus enneaporos were better during wet than dry season. Overall, the condition factor of all native fish species in the Murum River was in poor to fair condition, whereas the exotic species, Oreochromis mossambicus, exhibited excellent condition (K value > 2) for both seasons. The increase in the number of O. mossambicus coupled with its high condition factor indicates biological intrusion and a potential threat to the native fish species in the Murum River. Continuous monitoring is essential to detect in-time risk issues associated with environmental degradation and biological invasion in this regulated and inundated river ecosystem.

scholarly journals Diet composition of the Pharaoh Eagle Owl, Bubo ascalaphus (Strigiformes, Strigidae) in a Steppe region of Algeria

2021 ◽  
Vol 29 (2) ◽  
pp. 177-182
Author(s):  
Naceur Benamor ◽  
Toufik Guetouache ◽  
Farid Bounaceur
Keyword(s):  
Diet Composition ◽  
Bird Species ◽  
Total Biomass ◽  
Food Items ◽  
Important Prey ◽  
Steppe Region ◽  
Eagle Owl ◽  
Western Algeria ◽  
North Western ◽  
Prey Items

Abstract The diet composition of Pharaoh Eagle Owl (Bubo ascalaphus) was investigated in a semiarid area of North-western Algeria. A total of 65 pellets regurgitated by the B. ascalaphus were analysed, 288 food items were composed primarily of mammal remains (4 rodents, 1 bat and insectivore, 93.7%), and 1 bird species (passerine, 6.3%). The most frequent prey among the mammals were rodents (83.3%), which included Mus musculus (59.7%), Meriones shawi (11.1%), Meriones libycus (11.1%) and Jaculus jaculus (1.4%). The rodents were the most important prey items in biomass (91.4%), M. shawi made up to 41.9% of the total biomass. We may conclude that the Pharaoh Eagle Owl relies, in its feeding, very broadly on small mammals, completed by other groups.

scholarly journals Life in a harsh environment: the effects of age, sex, reproductive condition, and season on hair cortisol concentration in a wild non-human primate

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9365
Author(s):  
Paul A. Garber ◽  
Anna McKenney ◽  
Evelyn Bartling-John ◽  
Júlio César Bicca-Marques ◽  
María Fernanda De la Fuente ◽  
...  
Keyword(s):  
Dry Season ◽  
Cortisol Concentration ◽  
High Rate ◽  
Northeastern Brazil ◽  
Hair Cortisol ◽  
Wet Season ◽  
Common Marmosets ◽  
Wild Mammals ◽  
Juvenile Mortality ◽  
Adult Females

Hair cortisol concentration (HCC) provides a long-term retrospective measure of hypothalamic–pituitary–adrenal axis activity, and is increasingly used to assess the life history, health and ecology of wild mammals. Given that sex, age, season and pregnancy influence HCC, and that it may indicate ongoing stress, we examined HCC in common marmosets (Callithrix jacchus) naturally inhabiting a hot and dry semi-desert like habitat, Caatinga, in northeastern Brazil. We trapped, measured, weighed, marked and collected shaved hair from the back of the neck of 61 wild marmosets during the wet and dry seasons. Using enzyme immunoassay, we found that HCC was higher in the dry season compared with the wet season among all age/sex classes. Females had significantly higher HCC than males, juveniles had higher HCC than adults, and reproductively active adult females and non-pregnant/non lactating adult females did not differ in HCC. There were no interaction effects of sex, age, group, or season on HCC. The magnitude of the effect of this extremely hot and dry environment (average yearly rainfall was only 271 mm) on HCC in common marmosets is difficult to ascertain as these animals are also experiencing a variety of other stressors. However, the elevated HCC seen in common marmosets during the 5–8 month dry season, suggests these primates face an extended period of heat, water and possibly nutritional stress, which appears to result in a high rate of juvenile mortality.

scholarly journals Trophic ecology of Patagonian flounder Paralichthys patagonicus (Jordan, 1889) in the Argentine-Uruguayan Coastal Ecosystem

2021 ◽  
Vol 35 (1) ◽  
Author(s):  
Gonzalo H. Troccoli ◽  
Andrés C. Milessi ◽  
Noemí Marí ◽  
Daniel Figueroa ◽  
Agustín M. De Wysiecki
Keyword(s):  
Food Habits ◽  
Diet Composition ◽  
Trophic Ecology ◽  
Pelagic Fish ◽  
Coastal Ecosystem ◽  
Prey Category ◽  
Important Prey ◽  
Content Analyses ◽  
Size Groups ◽  
Wet Weight

Food habits and diet composition of Patagonian flounder Paralichthys patagonicus (Jordan, 1889) were studied on the basis of stomach content analyses from 828 specimens (512 females, 304 males, 12 unsexed) collected during 16 commercial cruises between February 2009 and April 2010 in the Argentine-Uruguayan Coastal Ecosystem (34° S-41° S). A total of 272 stomachs (32.9%) contained food (184 females and 84 males), among which 20 prey taxa were identified. The most important prey category was pelagic fish, primarily Argentine anchovy (Engraulis anchoita), followed by rough scad (Trachurus lathami). Evidence showed that females consumed a higher total wet weight of prey compared to males. Results also suggested a specialised diet over E. anchoita, across all sex and size groups. The estimated trophic level for the population of P. patagonicus was 4.16. This study suggests that P. patagonicus is a tertiary piscivorous consumer of the trophic food web in the region, and reveals changes in the prey consumption compared with previous studies.

A geospatial model for mapping desertification risk areas in the Caatinga biome, a semiarid region of Brazil

2020 ◽  
Author(s):  
Marcos César Ferreira ◽  
Mariana Monteiro Navarro de Oliveira ◽  
Danilo Carneiro Valente
Keyword(s):  
Logistic Regression ◽  
Regression Analysis ◽  
Logistic Regression Analysis ◽  
Vegetation Index ◽  
Dry Season ◽  
Northeastern Brazil ◽  
Wet Season ◽  
Mean Values ◽  
Risk Areas ◽  
The Mean

<p>Desertification is a process characterized by the degradation and drying of soils in arid, semiarid and subhumid regions that results from a combination of climatic factors and human activities. This process influences the productivity potential of the soils, impacting the populations residing in the affected areas, and may cause long-term economic problems and impacts on human health, such as hunger and food insecurity. The aim of this paper is to present a geospatial model for mapping desertification risk areas in northeastern Brazil. The test area for the model was located in the Brazilian semiarid climatic region in the state of Ceará. In this area, the dry season lasts for 7 to 8 months, and the original vegetation belongs to the Caatinga biome. The model was based on algebraic operations between maps of environmental variables, performed in a geographic information system, and based on equations obtained through logistic regression analysis. First, 300 points were mapped in the centroids of desertification polygons (D), and 300 points were mapped in areas where no desertification processes (ND) had occurred. All points were selected by visual interpretation of Sentinel-2A multispectral images. Then, 500 m radius buffers were mapped around the centroids of the D and ND areas, and the mean values of the following environmental variables were extracted within these buffers: the average annual rainfall (RAIN), altitude (ELV), vegetation index dry season (VID), wet season vegetation index (VIM), dry season soil temperature (LTD), and wet season soil temperature (LTM). The mean values ​​of the RAIN, ELV, VID, VIM, LTM and LTD variables for the D and ND areas were entered in the MedCalc software for logistic regression analysis. The <em>p</em> probability map of desertification occurrence was constructed in ArcGIS Pro using equations for which the parameters were obtained with the logistic regression analysis. The results showed that the variables RAIN, ELV, VID and LTD (p <0.0001) contributed significantly to the occurrence of desertification areas. The value obtained for the area under the ROC curve (AUC) parameter was 0.757, and the percentage of cases correctly classified by the model was 70.17%. In the next step of this research, this model will be tested on a larger area of 72,000 km<sup>2</sup> that is located in the Jaguaribe River basin, northeastern Brazil.</p>

scholarly journals Milk Composition of Asian Elephants (Elephas maximus) in a Natural Environment in Myanmar during Late Lactation

Animals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 725 ◽  
Author(s):  
Ellen S. Dierenfeld ◽  
Yadana A. M. Han ◽  
Khyne U. Mar ◽  
Aung Aung ◽  
Aung Thura Soe ◽  
...  
Keyword(s):  
Natural Environment ◽  
Diet Composition ◽  
Field Studies ◽  
Milk Composition ◽  
Dry Season ◽  
Wet Season ◽  
Free Living ◽  
Asian Elephants ◽  
Feeding Management ◽  
Captive Populations

The nutritional content of milk from free-living Asian elephants has not previously been reported, despite being vital for better management of captive populations. This study analyzed both milk composition and consumed plant species of Asian elephants managed in their natural environment in Myanmar. Longitudinal samples (n = 36) were obtained during both the wet and the dry season from six mature females in mid to late lactation in 2016 and 2017. Milk composition averaged 82.44% water, with 17.56% total solids containing 5.23% protein, 15.10% fat, 0.87% ash, and 0.18 µg/mL vitamin E. Solids and protein increased with lactation month. Total protein in milk was higher during the wet vs. the dry season. Observed factors linked with maternal (age, parity, size and origin) and calf traits (sex) had significant associations with milk nutrient levels. Primary forages consumed contained moderate protein and fiber. Higher dietary protein during the wet season (11–25%) compared to the dry season (6–19%) may be linked with increased milk protein observed. Our results call for further field studies of milk and diet composition, over entire seasons/lactation periods, and across maternal and calf traits, to improve feeding management, with an overall goal of maximized health and survival.

scholarly journals Niche differences between two sympatric whiptail lizards (Cnemidophorus abaetensis and C. ocellifer, Teiidae) in the restinga habitat of northeastern Brazil

2007 ◽  
Vol 67 (1) ◽  
pp. 41-46 ◽  
Author(s):  
EJR. Dias ◽  
CFD. Rocha
Keyword(s):  
Niche Differentiation ◽  
Sympatric Species ◽  
Northeastern Brazil ◽  
Activity Period ◽  
Microhabitat Use ◽  
Lizard Species ◽  
Niche Differences ◽  
Niche Dimension ◽  
Food Niche ◽  
Prey Items

Differences among sympatric lizard species usually result from differences in the use of three resources: space, time and food or some combination of these three. However, differences in resource utilization among sympatric species may simply reflect their specific ecological needs rather than competitive pressures. In this study, we analyzed the temporal, spatial and food niche of two congeneric teiids (Cnemidophorus abaetensis and C. ocellifer) living sympatrically in the "restinga" habitat of Abaeté in the Salvador Municipality, Bahia State, Brazil to assess the degree of niche differentiation among them. The whiptail species overlapped considerably in an hourly activity (Ojk = 0.93), in microhabitat use (Ojk = 0.97) and in the prey items consumed (Ojk = 0.89). Differences in amount of vegetation in the microhabitats used by both lizard species may have contributed to differences in the activity period and in the distribution of the main prey eaten by these lizards which may, in turn, facilitate their coexistence in Abaeté. Although sympatric C. ocellifer and C. abaetensis in Abaeté differed only slightly in their use of microhabitats, period of activity and diet, the most important niche dimension segregating the two species seemed to be the food niche.

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