Interrelationship between ectoparasites and wild rodents from northeastern Buenos Aires province, Argentina

Infestation parameters and indices of mites, ticks and fleas associated with wild rodents from northeastern Buenos Aires Province, Argentina, were studied. Host species similarity was also analyzed in relation to their ectoparasites. Fifty-five rodents were captured from January 2000 to March 2001. In total, 1,022 ectoparasites were collected and three ectoparasite-host associations were new records. However, this is the first study on Craneopsylla minerva wolffhuegeli infesting parameters. Ectoparasite total mean abundance and total prevalence were higher in Holochilus brasiliensis (MA = 47.7; P = 100%) and Scapteromys aquaticus (MA = 25.4; P = 95.4%), meanwhile specific richness and diversity were higher in Oligoryzomys flavescens (S = 6; H = 1.3) and Akodon azarae (S = 4; H = 1.0). On the other hand, the only individual of Calomys laucha was not parasited. S. aquaticus-H. brasiliensis, which preferred similar microhabitats, shared the same ectoparasite species (Css = 100). Whereas, A. azarae, which was mostly associated with grassland, showed the highest difference with the other hosts (Css < 0.4). Considering every ectoparasite species, H. brasiliensis showed the highest mean abundance, prevalence and preference. The results suggest that the particular characteristics of this rodent would give it better possibilities not only of being infested by ectoparasites, but also of transmitting them to its progeny

Quantitative paleoparasitology applied to archaeological sediments

Three techniques to extract parasite remains from archaeological sediments were tested. The aim was to improve the sensibility of recommended paleoparasitological techniques applied in archaeological remains. Sediment collected from the pelvic girdle of a human body found in Cabo Vírgenes, Santa Cruz, Argentina, associated to a Spanish settlement founded in 1584 known as Nombre de Jesús, was used to search for parasites. Sediment close to the skull was used as control. The techniques recommended by Jones, Reinhard, and Dittmar and Teejen were used and compared with the modified technique presented here, developed to improve the sensibility to detect parasite remains. Positive results were obtained only with the modified technique, resulting in the finding of Trichuris trichiura eggs in the sediment

Species-specific population trends detected for penguins, gulls and cormorants over 20 years in sub-Antarctic Fuegian Archipelago

Understanding the dynamics and causes of population trends are essential for seabird conservation. Long-term studies of seabirds at high-latitude (Antarctic, sub-Antarctic and Arctic) regions have shown contrasting species-specific trends in population size in response to climate change and anthropogenic pressures. We have studied for the last 20 years (1992?2012) the population trends of seven seabird species that breed in the Beagle Channel, south-eastern Tierra del Fuego and at Staten Island, a sub-Antarctic region in southern Argentina. The numbers of Magellanic and Gentoo Penguins increased significantly since 1992 (by[15 % year-1). In comparison, the populations of Imperial Cormorants, Dolphin Gulls and Kelp Gulls increased at slower rates ( % year-1), while the Rock Cormorant population even decreased by 1.3 % year-1. At Staten Island, the numbers of Rockhopper Penguins decreased by 24 % between the censuses of 1998 and 2010, whereas the population of Magellanic Penguins increased by 227 % during the same period. Over the study period, air and sea-surface temperatures remained stable in our study area, suggesting that the detected population changes are not driven by the climate. This finding contrasts with the detected links between increasing temperature trends and seabird population changes reported from Antarctic and Arctic regions. The level of tourism and size of the permanent human population has increased in the Beagle Channel area during the last 20 years and could be responsible for the increase of gull populations. The seabird species that received the highest number of visitors (Imperial Cormorants and penguin species) seem to be adapted or at least indifferent to pressures exerted by tourism, as their populations increased during the study period. In addition, increasing numbers of seabirds in the area may generally be leading to higher abundances of scavenging species (e.g. gulls).Fil: Raya Rey, Andrea Nélida. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Rosciano, Natalia Gimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Liljesthrom, Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Saenz Samaniego, Ricardo Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Schiavini, Adrian Carlos Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Wildlife Conservation Society; Estados Unido

A monitoring program for Patagonian foxes based on power analysis

Culpeo fox (Pseudalopex culpaeus) and gray fox (Pseudalopex griseus) are heavily culled in Patagonia. Fox populations seem to persist thanks to spatial refuges from which hunted areas are repopulated, following a source– sink dynamics. Sustainable use of Patagonian foxes warrants the design of a monitoring program in nature reserves and areas subjected to predator control. During 7 years, we used visitation indices to bait stations in a national park and neighboring sheep ranches of southern Argentina. We operated bait stations during three consec- utive nights and calculated seven indices of relative abundance. For each fox species, we compared the power of different monitoring designs and scenarios that combined visitation indices, effort (number of bait station lines and survey frequency) while controlling for type I error, and magnitude of population change during a given period. We looked at the combinations that produced high power (β ≤ 0.24). The operation of bait stations during several nights markedly increased statistical power. Index 7 (recording visits 72 h after activation) exhibited the lowest variation and improved expected power to detect a population trend. Both fox species could be monitored simultaneously, with power >0.76 in the short term (5 years), activating 24 bait station lines. We conclude that monitoring programs for culpeo fox and gray fox based on bait stations are able to detect marked declines but are less useful to reliably detect moderate increases in abundance, especially in sheep ranches.Peer reviewe