16 research outputs found
Biolog铆a alimentaria de la gallareta chica Fulica leucoptera en el valle de inundaci贸n del r铆o Paran谩 medio, Argentina
The article describes the feeding behavior of the white-winged coot
(Fulica leucoptera) by analyzing the stomach contents of 15
individuals with the stereoscopic microscope set to different degrees
of taxonomic resolution: trophic spectrum was integrated by 14
taxonomical entities (4 vegetables and 10 animals); trophic diversity
by stomach (H) oscillated between 0 and 1,95; accumulative trophic
diversity (Hk) was 2,55; relative importance index (RII) values
were Paspalum repens 253, Polygonum accuminatum 104,
Belostoma 78, among others; trophic niche amplitude by season
(estimated by using the Levins index) was 0,72 for summer, 0,46
for spring, 0,8 for fall and 0,86 for winter; prey percentages by size
depicted 82% for organisms between 0 and 10 mm; an intestinal
coefficient average (R) was 2,84. Based on those results, the author
concludes that the Fulica leucoptera is an omnivorous species,
mostly phytophagous.Se estudi贸 la biolog铆a alimentaria de la gallareta chica
Fulica leucoptera, analizando los contenidos estomacales
de 15 individuos bajo lupa estereosc贸pica a diferentes
grados de resoluci贸n taxon贸mica. Se calcul贸 la diversidad
tr贸fica por est贸mago (H) y la diversidad tr贸fica acumulada
(Hk). Se aplic贸 el 铆ndice de importancia relativa
(IRI). La amplitud tr贸fica del nicho fue estimada seg煤n
el 铆ndice de Levins. Se calcul贸 el porcentaje de las presas
por tama帽o y el coeficiente intestinal (Ri). El espectro
tr贸fico result贸 integrado por 14 entidades taxon贸micas:
4 (fracci贸n vegetal) y 10 (fracci贸n animal). La diversidad
tr贸fica por est贸mago oscil贸 entre 0 y 1,95. La diversidad
tr贸fica acumulada (HK) dio un valor de 2,55. Los valores
del IRI fueron: Paspalum repens 253, Polygonum accuminatum
104, Belostoma 78, entre otros. La amplitud del nicho
tr贸fico por estaci贸n arroj贸 un valor de 0,72 para verano,
0,46 para primavera, 0,8 para oto帽o y 0,86 para invierno.
El porcentaje de presas por tama帽o mostr贸 un 82% para
organismos que oscilaron entre 0 y 10 mm. El promedio
del coeficiente intestinal result贸 ser de 2,84. Con base en
los resultados obtenidos, se concluye que Fulica leucoptera
es una especie omn铆vora b谩sicamente fit贸faga
Biolog铆a alimentar铆a de la pollona pintada Porphyriops melanops (Aves: Rallidae) en el valle de inundaci贸n del r铆o Paran谩 medio, Argentina
A proposal for sustainable usage of rails population should
take into account complete alimentary requirements. Hence,
the purpose of the following study was to determine the feeding
biology of the Spot-flanked Gallinule Porphyriops melanops.
The research was conducted on 11 stomach contents
to find out trophic diversity by stomach (H), accumulated
trophic diversity (Hk), Relative Importance Index (IRI),
alimentary efficiency, prey size percentage and intestinal
coefficient (Ri). The resultant spectrum was composed by
10 taxonomical entities, 7 animal fractions and 3 vegetable
fractions; trophic diversity by stomach (H) ranged between 0
and 1, while accumulated trophic diversity (Hk) was 2,57;
main IRI values were as follows: Polygonum accuminatum
1204, Planorbidae 872 and Paspalum repens 451;
alimentary efficiency was 97,5%; more frequent prey sizes
oscillated between 0 and 10 mm; habitat preference was 2,4;
and the average intestinal coefficient was 2,79.Una propuesta de uso sustentable de las poblaciones
de r谩lidos debe incorporar el conocimiento de sus
requerimientos alimentarios. As铆, el prop贸sito de
este trabajo fue analizar la dieta de la pollona pintada
Porphyriops melanops. Se analizaron un total de
11 est贸magos, para los cuales se calcul贸 la diversidad
tr贸fica por est贸mago (H), la diversidad tr贸fica
acumulada (Hk), el 铆ndice de importancia relativa
(IRI), el porcentaje de las ingestas por tama帽o y el
coeficiente intestinal (Ri). El espectro result贸 integrado
por 10 entidades taxon贸micas, de las cuales
7 correspondieron a la fracci贸n animal y 3 a la fracci贸n
vegetal. La diversidad tr贸fica por est贸mago
(H) oscil贸 entre 0 y 1 mientras que la diversidad
tr贸fica acumulada (Hk) fue de 2,57. Los principales
valores del IRI fueron: Polygonum accuminatum 1204,
Planorbidae 872 y Paspalum repens 451. La eficiencia
alimentaria fue del 97,5% mientras que del tama帽o
m谩s usual de presas ingeridas oscil贸 entre 0 y 10 mm.
El valor obtenido de preferencia de h谩bitats fue de
2,4. Mientras que el promedio del Ri fue de 2,79
First evidence of the effects of agricultural activities on gonadal form and function in <em>Rhinella fernandezae</em> and <em>Dendropsophus sanborni</em> (Amphibia: Anura) from Entre R铆os Province, Argentina
<p>The relationship between male gonadal abnormalities and habitats with different degrees of agricultural activities was quantified in two anuran species, <em>Rhinella fernandezae</em> and <em>Dendropsophus sanborni</em>. The study sites were selected along a gradient of increasing agricultural land use in south-western Entre R铆os province (Argentina): an agroecosystem, a natural wetland (a non-agricultural site adjacent to monoculture zones), and a natural forest (not associated with agriculture). <em>Rhinella fernandezae </em>and <em>D. sanborni</em> were manually captured from each environment during field surveys. A scaled mass index (MI) was evaluated for each animal. Specimens of <em>R. fernandezae</em> from the agroecosystem and the natural wetland site presented poorly developed seminiferous tubules, lower testicular volume, and a lower number of seminiferous tubules, primary spermatogonia, and spermatids than specimens from the natural forest site. Additionally, we observed fewer primary spermatocytes in the agroecosystem group than in the natural forest group. Individuals of <em>D. sanborni</em> from the agroecosystem and the natural wetland site presented poorly developed tubules, higher proportions of irregularly shaped testes, and a reduced number of primary and secondary spermatogonia compared with specimens from natural forest sites. Consequently, the affected anurans are likely to have reduced reproductive success. We suggest that agrochemical use may be associated with decreased testicular development and function in both <em>R. fernandezae</em> and <em>D. sanborni</em> occurring in agroecosystems and nearby environments. Buffer zones are needed to prevent contamination, preserve wildlife, and enhance the conservation value of pristine natural forests.</p
First evidence of the effects of agricultural activities on gonadal form and function in Rhinella fernandezae and Dendropsophus sanborni (Amphibia: Anura) from Entre R铆os Province, Argentina
The relationship between male gonadal abnormalities and habitats with different degrees of agricultural activities was quantified in two anuran species, Rhinella fernandezae and Dendropsophus sanborni. The study sites were selected along a gradient of increasing agricultural land use in south-western Entre R铆os province (Argentina): an agroecosystem, a natural wetland (a non-agricultural site adjacent to monoculture zones), and a natural forest (not associated with agriculture). Rhinella fernandezae and D. sanborni were manually captured from each environment during field surveys. A scaled mass index (MI) was evaluated for each animal. Specimens of R. fernandezae from the agroecosystem and the natural wetland site presented poorly developed seminiferous tubules, lower testicular volume, and a lower number of seminiferous tubules, primary spermatogonia, and spermatids than specimens from the natural forest site. Additionally, we observed fewer primary spermatocytes in the agroecosystem group than in the natural forest group. Individuals of D. sanborni from the agroecosystem and the natural wetland site presented poorly developed tubules, higher proportions of irregularly shaped testes, and a reduced number of primary and secondary spermatogonia compared with specimens from natural forest sites. Consequently, the affected anurans are likely to have reduced reproductive success. We suggest that agrochemical use may be associated with decreased testicular development and function in both R. fernandezae and D. sanborni occurring in agroecosystems and nearby environments. Buffer zones are needed to prevent contamination, preserve wildlife, and enhance the conservation value of pristine natural forests
Wildlife vertebrate mortality in roads from Santa Fe Province, Argentina Mortalidad de vertebrados en caminos de la provincia de Santa Fe, Argentina
Mortality of vertebrates was monitored on 2 roads (National Road 168; NR168 and Provincial Road 1; PR1) in Santa Fe Province (Argentina) from October 2007 to August 2008. These roads differed in traffic volume and surrounding landscape management conditions. We also investigated the influence of environmental variables (mean monthly air temperature and monthly total rainfall) on the incidence of road kills. Two people monitored the roads on foot (1 000-m line transects), 3 times a month (36 samples per road). We found 2 024 vertebrate road killed specimens representing 61 species (7 amphibians, 15 reptiles, 32 birds, and 7 mammals). The toad Rhinella fernandezae was the most frequently killed species (n = 1307, 64.57%). NR168 had a higher incidence of vertebrate road kills, particularity for amphibians, whereas birds had a higher incidence of road kills on PR1. We found a positive correlation between precipitation and temperature with vertebrate road kills on PR1. We suggest that vertebrate road mortality is a very serious problem for the conservation of the biodiversity in Santa Fe Province-Argentina, therefore implementing mitigation measures will be necessary.Se estudi贸 la mortalidad de vertebrados en 2 rutas (RP1: Ruta Provincial N掳 1 y RN168: Ruta Nacional N掳 168) de la Provincia de Santa Fe (Argentina) desde octubre de 2007 hasta agosto de 2008. Estas rutas difer铆an en el tr谩nsito vehicular y obras de infraestructura. Adem谩s, se investig贸 la influencia de variables clim谩ticas (temperatura media mensual y precipitaci贸n total mensual) con el atropellamiento de la fauna silvestre. Se realizaron de 2 a 3 transectos por mes de 1 000 m cada uno, los cuales fueron recorridos a pie por 2 observadores. Un total de 2 024 vertebrados fueron registrados distribuidos en 61 taxa (7 anfibios, 15 reptiles, 32 aves y 7 mam铆feros). La especie m谩s impactada fue el sapo Rhinella fernandezae (n = 1307, 64.57%). La RN168 present贸 una alta abundancia de vertebrados particularmente de anfibios, mientras que las aves fueron m谩s representativas en la RP1. Se encontr贸 una correlaci贸n positiva entre las variables ambientales (precipitaci贸n y temperatura) con la mortalidad de vertebrados en la RP1. Sugerimos que la mortandad de vertebrados en la Provincia de Santa Fe, Argentina, es un problema serio para la conservaci贸n de la biodiversidad, siendo necesaria la implementaci贸n de medidas de mitigaci贸n
Hematolog铆a y citoqu铆mica de las c茅lulas sangu铆neas de Rhinella fernandezae (Anura: Bufonidae) en Espinal y Delta-Islas del r铆o Paran谩, Argentina
La descripci贸n de la hematolog铆a de los anfibios anuros es escasa, habi茅ndose realizado la mayor铆a de los trabajos en especies de Norteam茅rica, Asia y Europa. Con el prop贸sito de obtener datos hematol贸gicos para Rhinella fernandezae, fueron estudiados 23 espec铆menes provenientes de zonas protegidas de las provincias de Santa Fe y Entre R铆os. Se les extrajo sangre por punci贸n card铆aca y se realizaron hemogramas. En los extendidos sangu铆neos, se efectuaron la descripci贸n morfol贸gica y citoqu铆mica de las c茅lulas sangu铆neas y b煤squeda de par谩sitos. Se observaron cinco tipos de leucocitos, donde predominaron los linfocitos peque帽os. Heter贸filos y eosin贸filos resultaron positivos para PAS, Sudan B y peroxidasa; contrariamente, los eritrocitos y sus precursores fueron negativos. Los puntajes de las reacciones citoqu铆micas fueron variables para bas贸filos, linfocitos, monocitos y trombocitos. Las frecuencias de micron煤cleos y de alteraciones nucleares fueron escasas. No se observaron diferencias significativas (p>0.05) entre sexos en el hemograma ni en la morfolog铆a sangu铆nea. Los 煤nicos hemopar谩sitos encontrados fueron microfilarias (Nematoda: Filaroidea), cuya prevalencia e intensidad de infecci贸n fueron bajas. Las caracter铆sticas hematol贸gicas estudiadas fueron semejantes a los valores reportados para otros anfibios, pudiendo inferir que los individuos de R. fernandezae estudiados se encuentran en un buen estado nutricional e inmunol贸gico.<br>Hematology and blood cell cytochemistry of Rhinella fernandezae (Amphibia: Anura) from Espinal and Delta-Islands of Paran谩 River, Argentina. The description of amphibian hematology is scarce and most of these studies have been done in species from North America, Asia and Europe. With the purpose to obtain basic hematological information of Rhinella fernandezae, 23 blood samples from Santa Fe and Entre R铆os natural reserves were studied. Blood of each individual was extracted by cardiac puncture and hemograms were carried out. Morphological and cytochemical description of blood cells were analyzed in slides and were inspected for extra and intra cellular parasites. Five leucocytes types were observed, being lymphocytes the predominant ones followed by basophiles. Heterophils and eosinophils were positive to PAS, Sudan B and peroxidase. The erythrocytes and its precursors were negative for cytochemical reactions. Micronuclei and nuclear alterations frequencies were scarce. No significant differences (p>0.05) were observed between sexes neither in hemograms nor in blood cells morphology. Microfilarias were the only hemoparasites found with a relative low prevalence and infection intensity. The hematological characteristics studied were similar to those reported for other amphibians, suggesting that R. fernandezae individuals present optimal nutritional and immunological status. Rev. Biol. Trop. 59 (1): 17-28. Epub 2011 March 01
Hematolog铆a y citoqu铆mica de las c茅lulas sangu铆neas de Rhinella fernandezae (Anura: Bufonidae) en Espinal y Delta-Islas del r铆o Paran谩, Argentina
La descripci贸n de la hematolog铆a de los anfibios anuros es escasa, habi茅ndose realizado la mayor铆a de los trabajos en especies de Norteam茅rica, Asia y Europa. Con el prop贸sito de obtener datos hematol贸gicos para Rhinella fernandezae, fueron estudiados 23 espec铆menes provenientes de zonas protegidas de las provincias de Santa Fe y Entre R铆os. Se les extrajo sangre por punci贸n card铆aca y se realizaron hemogramas. En los extendidos sangu铆neos, se efectuaron la descripci贸n morfol贸gica y citoqu铆mica de las c茅lulas sangu铆neas y b煤squeda de par谩sitos. Se observaron cinco tipos de leucocitos, donde predominaron los linfocitos peque帽os. Heter贸filos y eosin贸filos resultaron positivos para PAS, Sudan B y peroxidasa; contrariamente, los eritrocitos y sus precursores fueron negativos. Los puntajes de las reacciones citoqu铆micas fueron variables para bas贸filos, linfocitos, monocitos y trombocitos. Las frecuencias de micron煤cleos y de alteraciones nucleares fueron escasas. No se observaron diferencias significativas (p > 0.05) entre sexos en el hemograma ni en la morfolog铆a sangu铆nea. Los 煤nicos hemopar谩sitos encontrados fueron microfilarias (Nematoda: Filaroidea), cuya prevalencia e intensidad de infecci贸n fueron bajas. Las caracter铆sticas hematol贸gicas estudiadas fueron semejantes a los valores reportados para otros anfibios, pudiendo inferir que los individuos de R. fernandezae estudiados se encuentran en un buen estado nutricional e inmunol贸gico