Capybara (Hydrochoerus hydrochaeris) distribution in agroecosystems: a cross-scale habitat analysis

Aim The aim of this study was to understand the spatial distribution of capybara (Hydrochoerus hydrochaeris) according to habitat attributes, using a multiscale approach based on fine‐ and broad‐scale variables in agroecosystems. Location Piracicaba river basin, south‐eastern Brazil (22°00′–23°30′ S; 45°45′–48°30′ W). Methods Potential habitats for capybara were selected in order to evaluate species presence/absence from October 2001 to December 2002. In each site, habitat attributes were sampled in the field (fine scale) and from GIS maps (broad scale) in terms of their presence or absence close to water. The variability of land cover between study sites was described by principal components analysis. Chi‐square tests were calculated for capybara presence/absence and the presence of each habitat attribute. A linear discriminant function analysis was used to describe to what extent the species’ presence could be explained by habitat attributes. Results The species presence was predominantly related to flat open areas (slope ranging from 0% to 6%) (χ² = 37.054, d.f. = 4, P < 0.001), covered by sugar cane or cultivated pasture (χ² = 84.814, d.f. = 9, P < 0.001). Terrain curvature, water meadows, aquatic vegetation, forest cover and open areas resulted in the best combination of variables, explaining 69.7% of capybara occurrence in the study sites in this river basin. Main conclusions Capybaras are widespread in the Piracicaba river basin, except in elevated areas. The spatial distribution of capybara was associated with the main types of land cover in the river basin – sugar cane plantations or pasture – both key food sources for capybara. This probably explains the species’ recent abundance in the region, since an intensive process of landscape alteration has taken place in this region owing to the expansion of agriculture in recent decades. These results may be useful in understanding the relationship between recent landscape modifications and the species’ population expansion in agroecosystems.     

Characterization of microsatellite markers from capybaras,Hydrochoerus hydrochaeris (Rodentia: Hydrochoeridae)

Fourteen microsatellite loci were isolated from capybaras (Hydrochoerus hydrochaeris), which are large, diurnal social rodents that occur in the wet savannas of South America. Five of these loci were monomorphic. The remaining nine loci were polymorphic (two to seven alleles per locus), with observed levels of heterozygosity ranging from 0.063 to 0.800 (n = 17 animals). The latter loci provide a valuable tool for assessing patterns of parentage and kinship within capybara social groups.     

Evaluation of three immobilization combinations in the capybara (Hydrochoerus hydrochaeris)

Capybaras (Hydrochoerus hydrochaeris) are the world's largest rodent. Owing to its uniqueness, 50 AZA institutions in North America display this species. As shown by a survey, no standard anesthetic protocol has been developed for this species. As a part of an ongoing behavioral study in Venezuela, capybaras were surgically implanted with radio transmitters. Animals were randomly assigned to one of the three immobilization protocols: (1) Tiletamine HCl/Zolazepam HCl, (2) Tiletamine HCl/Zolazepam HCl/Medetomidine HCl, and (3) Tiletamine HCl/Zolazepam HCl/Medetomidine HCl/Butorphanol tartrate. The protocol recommended for minimally invasive procedures when inhalant anesthetics are unavailable is a combination of Tiletamine HCl/Zolazepam HCl/Medetomidine HCl/Butorphanol tartrate. This is based on ease of administration, volume, onset of action, depth of anesthetic achieved, reversibility, safety, and costs. Zoo Biol 29:59–67, 2010. © 2009 Wiley‐Liss, Inc.     

Rumen ophryoscolecid protozoa in the hindgut of the capybara (Hydrochoerus hydrochaeris)

Rumen ophryoscolecid protozoa were observed in feces obtained from two capybara (Hydrochoerus hydrochaeris) housed at the Columbus Zoo, Columbus, Ohio. Total numbers were 58.1 X 10(4) and 19.0 X 10(4) per gram of wet feces in a male and female capybara, respectively. Four common rumen species of Entodinium were observed in the feces from both animals, with low numbers of Eudiplodinium maggii and Elytroplastron bubali also occurring in the male. Establishment of rumen ophryoscolecid ciliates in the intestinal tract of non-ruminant herbivores has not been reported previously.     

Aloina and Aloinella (Bryopsida, Pottiaceae) in northern Argentina

Except for a robust habit, two specimens ofAloina collected in northern Argentina are morphologically similar and are tentatively attributed toA. rigida (Hedw.) Limpr. This represents an addition to the moss flora of Argentina. In addition, two specimens ofAloinella represent significant findings: one shows features that agree with those given in the protologue forA. galeata (Müll. Hal.) Broth. and is treated here asA. galeata var.galeata to show the relationship toA. galeta var.andina (Delgad.) Delgadillo & Schiavone stat. nov.; the other belongs inA. cucullifera (Mitt.) Steere, a new record for Argentina. A key to the known species ofAloinella with updated ranges is included.     

Two new species of Haplopappus (Astereae, Asteraceae) from Mendoza, Argentina

A review of the Argentinean specimens ofHaplopappus Cass. has revealed two new species from Mendoza province, both of the sectionHaplopappus:H. boelkei, unique by its caespitose habit and long petiolate leaves, andH. mendocinus, related toH. macrocephalus (Less.) DC.,H. ochagavianus Phil. andH. tiltilensis Phil.     

Population dynamics of Stylaria lacustris (Linnaeus, 1767) (Oligochaeta,Naididae) in Los Talas,Argentina

Population dynamics of Stylaria lacustris were analyzed over 2 years in a pond located at Los Talas, Argentina. In both years, the peak in abundance, due to intense asexual reproduction, fell at the end of winter, and was followed by mature individuals. The species was not collected during summer. Temperature was the main factor regulating the population through both sexual and asexual reproduction. In the second year, density was lower and correlated with a lower water level and a reduced vegetation development. Individuals were randomly distributed in periods of high abundance and contagious when density was low. Generation time was 15 days.     

The genus Dyschoriste (Acanthaceae) in Bolivia and Argentina

Recent field work in Bolivia has resulted in the recognition of new species ofDyschoriste (Acanthaceae). These novelties are introduced here for the convenience of other taxonomists prior to the publication of a treatment of the Acanthaceae of Bolivia. Three new Bolivian and one new Argentinean species ofDyschoriste,D. axillaris, D. boliviana, D. ceciliae, andD. prostrata are described, illustrated, and compared to their closest relatives.     

Surveys of Undaria pinnatifida (Laminariales,Phaeophyta) in Golfo Nuevo,Argentina

In December 1992, some sporophytes of the Asian kelp Undaria pinnatiftda were found growing subtidally at 6 m depth below A. Storni Port, Puerto Madryn, Argentina. During the winter of 1994, the species expanded significantly from its original location. Sporelings appear in early autumn and attain their maximum size (1.65 ± 0.10 m) during winter and early spring, when most of them become fertile. The fronds are lost in summer, with only some holdfasts and sporophylls surviving, and these disappear by the end of summer. The occurrence of U. pinnatida in Golfo Nuevo is reportedly due to an accidental introduction by cargo ships or fishing vessels arriving from Asian ports.     

The influence of environmental variables on capybara (Hydrochoerus hydrochaeris: Rodentia, Hydrochoeridae) detectability in anthropogenic environments of southeastern Brazil

Capybaras were monitored weekly from 1998 to 2006 by counting individuals in three anthropogenic environments (mixed agricultural fields, forest and open areas) of southeastern Brazil in order to examine the possible influence of environmental variables (temperature, humidity, wind speed, precipitation and global radiation) on the detectability of this species. There was consistent seasonality in the number of capybaras in the study area, with a specific seasonal pattern in each area. Log-linear models were fitted to the sample counts of adult capybaras separately for each sampled area, with an allowance for monthly effects, time trends and the effects of environmental variables. Log-linear models containing effects for the months of the year and a quartic time trend were highly significant. The effects of environmental variables on sample counts were different in each type of environment. As environmental variables affect capybara detectability, they should be considered in future species survey/monitoring programs.     

A new Astragalus (Leguminosae) from Argentina, notable for placentation of its seeds

From the Patagonian region in ArgentinaAstragalus neocarpus is described and illustrated. The false septum of its fruit is formed by union of the seed-funicles with the endocarp.

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Se describe e ilustraAstragalus neocarpus de la región Patagónica de Argentina, su principal característica distintiva es la morfología del fruto, donde el falso tabique que divide en dos a la cavidad está formado por la unión de largos funículos de las semillas con el endocarpo.

     

A new species of Grindelia (Asteraceae, Astereae) from the Meseta del Somuncura (Patagonia), Argentina

Grindelia coronensis, a new species from the Meseta del Somuncura, Prov. Río Negro, Argentina, is described and illustrated. It is similar toG. chiloensis (Cornel.) Cabrera but it is readily distinguished by its leaves which are conspicuosly differentiated into a obovate blade and a long petiole.     

A new Diacyclops (Copepoda,Cyclopoida, Cyclopidae) from northwestern Argentina

No species of the genus Diacyclops has been so far cited from continental Argentina. Specimens collected from a roadside pool in the province of Catamarca on a plateau at 3700 m a.s.l. turned out to belong to a new species, Diacyclops andinus, which is described and illustrated in detail for both sexes. Main diagnostic features are: spine formula of swimming legs 3, 4, 4, 4; terminal spines of the distal endopod segment of leg 4 subequal; smooth furcal rami. The new species is a member of the D. bicuspidatus group, and is probably near the base of this line.     

Reproductive pattern of the freshwater prawn Pseudopalaemon bouvieri (Crustacea,Palaemonidae) from hypo-osmotic shallow lakes of Corrientes (Argentina)

Pseudopalaemon bouvieri undergoes complete abbreviated development. The reproductive cycle (proportion and size of the sexually mature population and juvenile recruitment), fecundity and egg size of this prawn were examined in three subtropical shallow lakes. The reproductive cycle was seasonal; gonadal maturation occurred during the winter, ovigerous females were abundant in the spring and breeding occurred at the end of spring. Females produced small numbers of eggs (9–55) of relatively large sizes (1.0–2.1 mm). The proportion of ovigerous females with respect to the total number of females, the fecundity and egg size differed among the lakes according to the trophic state of the environments. Pseudopalaemon bouvieri has a reproductive strategy similar to other Palaemonidae species that inhabit nutrient-poor inland waters.     

First Record of Undaria Pinnatifida (Laminariales, Phaeophyta) in Southern Patagonia, Argentina

The Japanese kelp Undaria pinnatifida was found on 7th September 2005 in Ría Deseado (Santa Cruz, Argentina). This invasive algae was registered from the lower intertidal to the upper levels of the subtidal zone. The sporophytes were fixed to slabs, gravel and rocks of variable sizes and were also present as epibionts of tunicates. The sporophytes total length ranged between 3 and 88 cm, with a mean of 28.75 cm in the intertidal and 38.3 cm in the subtidal. The density and biomass increased from the intertidal to the subtidal. The kelp population showed a higher number of small immature individuals in the intertidal than␣subtidal where the organisms were bigger and with more individual biomass. This first record of U. pinnatifida in Southern Patagonia extends its southern distribution limit in Argentina, showing progressive expansion in the southwestern Atlantic. More surveys must be conducted to understand the evolution of U. pinnatifida invasion and its impact on the native benthic community.     

Differential Distribution of Gonadotropin-Releasing Hormone Variants in the Brain of Hydrochaeris hydrochaeris (Mammalia, Rodentia)

1.In a previous paper we reported evidence for the presence of mGnRH- and sGnRH-like peptides in the preoptic–hypothalamic region of the capybara Hydrochaeris hydrochaeris (Montaner et al., 1998). In that study, the presence of a cGnRH-II like molecule in olfactory bulb extracts was suggested.2.The capybara, the largest living rodent in the world, belongs to the order Hystricomorpha, which is considered to be one of the oldest groups of rodents. Some authors consider that this group is the ancestor of all remaining rodents.3.In this study we have characterized GnRH molecular variants found in extracts from the olfactory bulbs and the mesencephalic region of capybara. These regions represent the two GnRH neuronal systems: the terminal nerve–septopreoptic and the midbrain systems.4.An indirect method combining reverse-phase high-performance liquid chromatography (RP-HPLC) and radioimmunoassay (RIA) was used to characterize GnRH variants. The analysis of both extracts with two different RIA systems revealed three immunoreactive GnRH peaks, coeluting with mGnRH, cIIGnRH, and sGnRH synthetic standards. These results were additionally supported by serial dilution studies with specific antisera.5.To our knowledge this the first report on the presence of three GnRH variants in the brain of an eutherian mammal. These results suggest that, similarly to other vertebrates, the expression of multiple GnRH variants may also be a common pattern in mammals.     

A new species of Solanum subgen. Leptostemonum (Solanaceae) from Argentina

Solanum homalospermum (Solanum subgen.Leptostemonum) is described and illustrated from central Argentina.Solanum homalospermum is characterized by having heteromorphic gynoecia, strongly flattened seeds, unequal anthers, and gemmiferous roots.