Physiological and behavioral indices of short-term stress in wild vicuñas (Vicugna vicugna) in Jujuy Province,Argentina

The management of wild vicuñas can trigger a stress response that may compromise welfare. In Santa Catalina, Jujuy Province, Argentina, indices of short-term stress associated with capture, handling, and shearing were studied in 105 wild vicuñas (Vicugna vicugna). The study included 2 groups (n = 59 and n = 46) of wild vicuñas captured in 2 consecutive days. Independent variables analyzed included sex, restraint time, and groups. Cortisol, creatine kinase, glucose, white blood cells, temperature, heart rate, and respiratory frequency were higher than published values. Respiratory rate increased during handling and correlated with holding time and group size, while heart rate decreased. Packed cell volume was higher in females. Cortisol concentrations differed between restraint groups and sex and inversely correlated with agonistic behavior. The most common behavior was increased vigilance. Sternal recumbency increased over holding time. During handling procedures, frequency of sudden movements like kicking and attempts to stand increased as restraint time increased. Females vocalized more than males. In conclusion, the methods used triggered measurable changes suggestive of short-term stress that appeared to be physiologically tolerated by the vicuñas.     

Climate–growth analysis of Qilian juniper across an altitudinal gradient in the central Qilian Mountains, northwest China

In the context of global warming, it is of high importance to assess the influence of climatic change and geographic factors on the radial growth of high-elevation trees. Using tree-ring data collected from four stands of Qilian juniper (Juniperus przewalskii Kom.) across an altitudinal gradient in the central Qilian Mountains, northwest China, we compared the radial growth characteristics and climate–growth relationships at different elevations. Results indicated that there was little difference in the tree-ring parameters of the four chronologies. Correlation analyses both for unfiltered and 10-year high-passed data of monthly climatic variables and chronologies were presented to investigate the climatic forcing on tree growth, and results revealed that the correlation patterns were consistent among the four sites, especially for high-passed data. We employed the principal components analysis method to obtain the first principal component (PC1) of the four chronologies and computed the correlations between PC1 and climate factors. The PC1 correlated significantly with winter (November–January) temperature, prior August and current May temperature, and precipitation in the previous September and current January and April, indicating that tree growth in this region was mainly limited by cold winter temperature and drought in early growing season and prior growing season (prior August and September). However, the climate–growth relationships were unstable; with an increase in temperature, the sensitivity of tree growth to temperature had decreased over the past few decades. Considering the instability of the climate–growth relationships, climate reconstructions based on tree rings in the study area should be approached with more caution.     

Phylogeography and subspecies assessment of vicuñas in Chile and Bolivia utilizing mtDNA and microsatellite markers: implications for vicuña conservation and management

The rearing and maintenance of wildvicuñas in semi-captivity for economicutilization is practiced mainly in Peru, butArgentina, Bolivia, and Chile are quicklydeveloping their own programs of economic use. Large scale rearing practices will likelyisolate populations and may foster selectivebreeding. In addition to these concerns, thereare also uncertainties about the distributionand validity of the currently recognizedsubspecies. To better understand the potentialimpact that economic utilization will have onthe vicuña, we describe the moleculargenetic variation among four populations andboth described subspecies. An analysis of 794~bp of mitochondrial DNA sequences (16s,cytochrome b genes, and mtDNA control region)revealed appreciable genetic diversity, low tomoderate levels of genetic differentiation, andrestricted gene flow with isolation by distanceamong populations. Analysis of microsatellitedata also indicated genetic differentiationamong populations. Past climatic and geologicevents, coupled with human history, have likelysubjected the vicuña to various episodes ofpopulation isolation and admixture. Therefore,we suggest that managers aim to ensure geneflow among adjoining populations, as observedat mtDNA and microsatellite loci, as well asmaintaining apparent restricted gene flow withisolation by distance among populationsseparated by great distances. Intensiverearing procedures like those being practicedin Peru will ultimately disrupt movements andmigration among wild populations. Furthermore,animals that are not exposed to predation byremaining inside fences, may overtime, loseportions of their behavioral repertoire thatenable them to recognize potentially dangeroussounds associated with the presence ofpredators. Therefore, we do not recommend thatanimals be placed behind fences as this couldlead to a loss of genetic and behavioraldiversity as well as halting natural ecologicalprocesses. If, however, vicuñas are placedbehind fences for commercial purposes (withlittle or no regard for the retention ofgenetic, and/or behavioral diversity as well asnatural population processes) then we suggestclose genetic monitoring of animals that are(will be) maintained in captivity.     

Effects of capture,shearing, and release on the ecology and behavior of wild vicuñas

The goals of sustainable use of wildlife include minimizing long term deleterious impacts of management. We evaluated the ethoecological and demographic responses of wild vicuñas (Vicugna vicugna) to capture, shearing, and release in northern Argentina, as well as effects on behavior, by comparing captured and shorn versus non-captured animals for 2 yr after capture events. We observed subtle and short-term changes in the movement behavior of individuals, likely due to thermal and behavioral stress following capture. We did not observe changes in survival and birth rates, social organization, or distribution of animals following capture. Therefore, we concluded that the capture techniques used resulted in low impacts on the wild vicuña population. © 2011 The Wildlife Society.     

Ordination and classification of vegetation along an altitudinal gradient in the Venezuelan páramos

By means of ordination and classification techniques, the relationships between climate, soils, human activities and vegetation along an altitudinal gradient of the Venezuelan páramos are analyzed and interpreted. The altitudinal gradient chosen is characterized by decrease of temperature, precipitation, soil fertility, soil water-holding capacity, and plant cover as altitude increases. The ordination results suggest vegetation changes to be primarily related to environmental changes occurring with altitude, and secondly to disturbances caused mainly by grazing. Some results point toward a disjunction in the vegetational gradient occurring at ca. 3 500 m.a.s.l. and separating low and high páramo. This disjunction might have been caused by the glacial history of the páramos and the occurrence of frequent night-frosts.The soil samples were kindly analyzed by the Laboratorio de Edafologia, Centro Nacional de Investigaciones Agropecuarias. Help in plant identification was generously obtained from the specialists of Instituto Botánico, Instituto Nacional de Parques, Caracas.Nomenclature follows Vareschi (1970).Acknowledgements: This work was supported by the Decanato de Investigaciones, Universidad Simón Bolivar. I wish to thank A. Pacheco for help in the field sampling. Dr O. Arenas help was invaluable in the mathematical treatment of the data. Drs A. Vivas and J. M. B. Smith provided useful criticism to an earlier version of this work.     

Social group dynamics and composition of managed wild vicuñas (<Emphasis Type=Italic>Vicugna vicugna vicugna</Emphasis>) in Jujuy,Argentina

The vicuña is a high Andean wild camelid that lives year-long in groups. We analyzed the social organization of 98 marked vicuñas after capture and live shearing, focusing on group composition, spatial patterns, territoriality and habitat use. The social units analyzed were families, bachelor groups and solo animals. Location fixes of 54 males and 36 females were registered over a 2-year period, and home range was estimated. All females belonged to family groups, and 8–12 month yearlings changed their home ranges prior to first reproduction at 2 years. Female yearlings dispersed to a new family group, while male yearlings dispersed to a bachelor group. Solitary males appeared during the interval between leaving bachelor or family groups, and vice versa. Our study showed that vicuña polygyny was based on female grazing area requirements. Females that stayed with the same males were defined as loyal, and had a mean 18.9 ha home range. Females that changed both to a different family and male; and grazed over the same home range size, were considered disloyal. Family groups selected the habitat that had a low stratum and the highest coverage of palatable plants, while bachelors used their habitat randomly.     

Diversity and distribution of Odonata (Insecta) larvae along an altitudinal gradient in Coalcomán mountains, Michoacán, Mexico

Evaluating components of landscape diversity is essential for the implementation of efficient conservation strategies. We evaluated the diversity of Odonata larval assemblages from the Coalcomán mountains (CM), Michoacán, Mexico, and related it to local (site-level) habitat variables. Larvae were collected from shores, riffles and pools in five streams, counted and identified to species, twice per season during 2005. The Shannon Diversity Index (H'), Margalef's Richness Index (R), Simpson's Index as a dominance measure (D) and Pielou's Equitability (J) were used to describe the assemblages, and Renyi's Diversity Profiles were used to order diversity. A Bray-Curtis Similarity Index (BC) was used to evaluate beta diversity. Theoretical richness was estimated using non-parametric and parametric methods. A Canonical Correspondence Analysis (CCA) was applied to explore the relationships of species with site-level environmental variables. A total of 12 245 larvae from 75 species, 28 genera and 8 families were recorded. Over all sites, the dominant species were Erpetogomphus elaps, Macrothemis pseudimitans and Argia pulla. The number of species per locality ranged from 18 to 36, and a high number of species (76%) occurred with relative abundances lower than 1%. A differential distribution of species and abundance in streams, time and strata was observed. Renyi's diversity profiles showed diversity was higher in spring and on shores. Most BC similarity values were smaller than 25%, indicating a high turnover rate in the CM. The high turnover rate reflects a differential distribution of the species along the altitudinal gradient, supporting the hypothesis of Mexico as a betadiverse country. According to the slope of Clench's curve, a reliable list of species was gathered. The CM larval assemblage is currently the largest reported for Mexico, and our results support previous proposals of the CM as a species-rich area for conservation.     

Elevational speciation in action? Restricted gene flow associated with adaptive divergence across an altitudinal gradient

Evolutionary theory predicts that divergent selection pressures across elevational gradients could cause adaptive divergence and reproductive isolation in the process of ecological speciation. Although there is substantial evidence for adaptive divergence across elevation, there is less evidence that this restricts gene flow. Previous work in the boreal chorus frog (Pseudacris maculata) has demonstrated adaptive divergence in morphological, life history and physiological traits across an elevational gradient from approximately 1500–3000 m in the Colorado Front Range, USA. We tested whether this adaptive divergence is associated with restricted gene flow across elevation – as would be expected if incipient speciation were occurring – and, if so, whether behavioural isolation contributes to reproductive isolation. Our analysis of 12 microsatellite loci in 797 frogs from 53 populations revealed restricted gene flow across elevation, even after controlling for geographic distance and topography. Calls also varied significantly across elevation in dominant frequency, pulse number and pulse duration, which was partly, but not entirely, due to variation in body size and temperature across elevation. However, call variation did not result in strong behavioural isolation: in phonotaxis experiments, low‐elevation females tended to prefer an average low‐elevation call over a high‐elevation call, and vice versa for high‐elevation females, but this trend was not statistically significant. In summary, our results show that adaptive divergence across elevation restricts gene flow in P. maculata, but the mechanisms for this potential incipient speciation remain open.     

Habitat use and sensitivity to fragmentation in America’s smallest wildcat

Fragmentation and human-wildlife conflicts represent severe threats to wildcats such as the kodkod cat (Leopardus guigna), endemic to the heavily impacted Chilean temperate rainforest. Here we assess to which extent this vulnerable forest specialist is able to use altered habitat (agricultural matrix, forest edge, human presence) by studying its home ranges, habitat use, and patch selection in privately owned rainforest remnants. We radio-tracked five individuals over 33–376 days. Mean 95% kernel home ranges were 623 ha, with a mean 50% core area of 191 ha. Ecological-niche and Mahalanobis distance factor analysis confirmed forest-dependency and revealed that the individuals made intensive use of forest edges, close to water. They did not avoid houses. Generalized linear mixed models showed that the monitored kodkods selected elongated woodland patches. We conclude that the kodkods compensated the non-forest space by maintaining larger home ranges and making efficient use of forest edges probably due to higher prey availability. Future studies should identify ecological traps, and describe connectivity and source-sink dynamics in the agricultural matrix to develop long-term conservation efforts for the smallest cat of the Americas.     

Steady-state two-dimensional maps of very alkaline proteins in an immobilized pH 10–12 gradient,as exemplified by histone types

Two-dimensional steady-state patterns of histones are here reported for the first time. The first dimension run consists in nonlinear immobilized pH gradients, spanning the pH 10–12 range. The second dimension run is a standard SDS-PAGE in a constant concentration (15% T) gel slab, in presence of a 6% T stacking gel. All the histone fractions analysed (II-AS, VI-S, VII-S and VIII-S) exhibit pI values between pH 11 and 12. The M_r values range from 13 to 32 kDa, with the heaviest distribution around 18 kDa. When running all different histone fractions in a single mixture, and analysing the 2-D gel by computerized image data acquisition, a total of 35 individual spots is detected.     

Does thermal history affect metabolic plasticity?: a study in three Phyllotis species along an altitudinal gradient

(1) The aim of this study was to understand the effects of thermal history in metabolic features such as maximum (MMR) and basal (BMR) metabolic rates, as well as in metabolic plasticity, considered as the total variation of MMR and BMR during the acclimation period. (2) We studied three species of the genus Phyllotis, from different thermal environments, in an altitudinal gradient from sea level to 3800m.a.s.l. Animals were acclimated to contrasting temperatures of 5 and 30 degrees C. To determine the metabolic flexibility, MMR was measured at intervals of 6 days during the acclimation period, while BMR values were obtained at the end of acclimations. Aerobic scope and the rates of change of MMR were estimated in all populations. (3) High- and low-altitude rodents did not show differences in BMR. However, both upper and lower limits of MMR, as well as aerobic scope, were significantly different between high- and low-altitude species, indicating similar ranges of metabolic plasticity. On the other hand, the rates of change of MMR were similar in all populations. (4) Our results indicate that thermal history has a profound effect on the individuals' thermogenic capacity, probably in both phylogenetic and ontogenetic levels. Low-altitude species could not increase MMR to the same levels as high-altitude species, while the later were unable to decrease MMR to achieve the values of the low-altitude species.     

Frequency, abundance and distribution of zoosporic organisms from Las Cañas stream (Buenos Aires, Argentina)

Zoosporic organisms are common inhabitants of aquatic environments; however there are few ecological studies made for Argentinean streams. In this contribution the taxonomic composition of zoosporic organisms from a stream and their abundance, frequency and diversity on cellulosic baits were analyzed. Samples of water and floating organic matter (vegetable debris) were taken at four dates and different environmental variables (temperature, dissolved oxygen and nutrient concentrations) were measured. Twenty-one taxa were recovered with the baiting technique. Physicochemical fluctuations affected the structure of the studied community; in spring the greatest species richness was related to high nutrient levels whereas in winter the greatest abundance and diversity was related to low water temperature, nutrient levels and well oxygenated conditions. aquatic environment,     

Size-based intraspecific variations along altitudinal gradient and follow of Bergmann’s rule in Parthenium beetle,Zygogramma bicolorata Pallister

Body size in insects is coupled with numerous physiological, life-history and ecological traits. Its variation along temperature gradient is widely studied. However, information regarding variations in body size of insects along altitudinal gradient is limited. Present study was designed considering hypothesis that there would be an increase in body size of Parthenium beetle, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae) with increasing altitude and decreasing in temperature. To achieve the objectives, beetles were collected from three eco-climatic zones of NEPAL [Kathmandu (1400 mts, 24 °C; warm temperate zone), Chitwan (415 mts, 25 °C; upper tropical/sub-tropical zone), and Mahendranagar (229 mts, 34 °C; humid subtropical zone)], and one of INDIA [Varanasi (81 mts, 36 °C; humid subtropical zone)] for their morphometric analysis (body length and body biomass). Results revealed that the size of beetles in all eco-climatic zones increased with increasing altitude and decreasing temperature. While adults of Kathmandu were largest, followed by Chitwan and Mahendranagar, but those of Varanasi were smallest in size. The sex ratio was female-biased in Kathmandu and Varanasi, but was male-biased in Chitwan and Mahendranagar. Irrespective of temperature and altitude, females were larger than males in all eco-climatic zones. Our results affirmed our hypothesis and were in compliance with Bergmann’s rule. The findings may be helpful in understanding phenotypic plasticity and distribution pattern of Z. bicolorata adults in Indian sub-continent under global climate change scenario.     

Soil nitrate accumulation, leaching and crop nitrogen use as influenced by fertilization and irrigation in an intensive wheat–maize double cropping system in the North China Plain

There is a growing concern about excessive nitrogen (N) and water use in agricultural systems in North China due to the reduced resource use efficiency and increased groundwater pollution. A two-year experiment with two soil moisture by four N treatments was conducted to investigate the effects of N application rates and soil moisture on soil N dynamics, crop yield, N uptake and use efficiency in an intensive wheat–maize double cropping system (wheat–maize rotation) in the North China Plain. Under the experimental conditions, crop yield of both wheat and maize did␣not␣increase significantly at N rates above 200 kg N ha⁻¹. Nitrogen application rates affected little on ammonium-N (NH₄-N) content in the 0–100 cm soil profiles. Excess nitrate-N (NO₃-N), ranging from 221 kg N ha⁻¹ to 620 kg N ha⁻¹, accumulated in the 0–100 cm soil profile at the end of second rotation in the treatments with N rates of 200 kg N ha⁻¹ and 300 kg N ha⁻¹. In general, maize crop has higher N use efficiency than wheat crop. Higher NO₃-N leaching occurred in maize season than in wheat season due to more water leakage caused by the concentrated summer rainfall. The results of this study indicate that the optimum N rate may be much lower than that used in many areas in the North China Plain given the high level of N already in the soil, and there is great potential for reducing N inputs to increase N use efficiency and to mitigate N leaching into the groundwater. Avoiding excess water leakage through controlled irrigation and matching N application to crop N demand is the key to reduce NO₃-N leaching and maintain crop yield. Such management requires knowledge of crop water and N demand and soil N dynamics as they change with variable climate temporally and spatially. Simulation modeling can capture those interactions and is considered as a powerful tool to assist in␣the␣future optimization of N and irrigation managements. Section Editor: L. Wade     

The Allerød/Younger Dryas transition in Wolin Island, northwest Poland, as reflected by pollen, macrofossils, and chemical content of an organic layer separating two aeolian series

A palaeoecological study including pollen, macrofossils, and chemical analyses of an organic sediment separating two series of aeolian cover sands has enabled us to reconstruct environmental changes during the Allerød/Younger Dryas transition in Wolin Island, northwest Poland. The Allerød woodland dominated by Pinus sylvestris became more open at the beginning of the Younger Dryas, when aeolian (wind) activity resulted in instability of the soil. During the early phase of the Younger Dryas the water level in the local basin distinctly raised, indicating a change to a wetter climate. This short-lasting phase was followed by an increased frequency and intensity of aeolian processes. However, the main aeolian event took place before the major expansion of Juniperus, not later than 10,780±120 b.p. Frequent woodland fires, probably due to the activities of Palaeolithic people, have been documented both for the Allerød and the Younger Dryas periods. Macrofossils of Alnus sp. found in the Allerød layer are of special interest in showing the presence of alder trees in northwest Poland as early as the Late-glacial.