High Sites Research Articles

Restos de pingüinos del Cenozoico medio de la cordillera Patagónica.

Middle Cenozoic marine fossil-bearing beds crop out in the Cerro Plataforma (western Chubut Province, Argentina) at about 1,400 m a.s.l. They are located 500 km far from the modern Atlantic coast and only 50 km from the Pacific Ocean. Well preserved penguin bones and a shark tooth were found therein. Invertebrates include corals, bryo- zoans, abundant mollusks, echinoids, and crabs. Morphogeometric analysis and comparative description confirmed that the penguin humerus is referable to Palaeospheniscus bergi Moreno and Mercerat, 1891. Most of the fossils indicate a Miocene age. However, there is a debate about if the bearing beds are of Pacific or Atlantic origin. Fossil invertebrates identifiable at species level reveal Pacific affinity, the shark species is cosmopolitan, and Palaeospheniscus bergi is known from early Miocene Atlantic units of southern South America. Yet, Palaeospheniscus Moreno and Mercerat, 1891 is also known from Miocene Pacific beds but it has not been identified at specific level yet. This is the highest site in topographic terms in which penguin fossils occur. This indicates a remarkable uplift for the area, probably from the middle Miocene.

Seasonal patterns of testate amoeba diversity, community structure and species–environment relationships in four Sphagnum-dominated peatlands along a 1300 m altitudinal gradient in Switzerland

Altitudinal gradients are useful to study the potential effects of climate change on ecosystems. Historically, studies on elevation gradients have primarily focused on macro-organisms and ecosystem processes, while microorganisms have been mostly ignored despite their ubiquity and functional importance. We studied the temporal (about every two months from June 2008 until May 2009) variation of testate amoeba communities in four Sphagnum-dominated peatlands along a 1300 m elevation gradient in the Swiss Mountains (580–1880 m) in relation to water table depth and hydrochemistry with special focus on dissolved organic carbon (DOC), a useful proxy for changes in C-cycling in peatlands.The lowest site had significantly (P < 0.01) lowest testate amoeba density, species richness. The highest site had highest testate amoeba density (38 ind mg−1 dry mass of Sphagnum). Seasonal fluctuations in testate amoeba species richness and diversity were not consistent among sites but density tended to peak in spring at all sites, autumn in the three highest sites and mid-winter in the upper two sites. In a redundancy analysis (RDA) community structure was more strongly correlated to altitude (33.8% of variance explained in living community) than to soil hydrological and hydro-chemical variables (together explaining 16.2% of variance). In a partial RDA with altitude used as covariable, the four sites were separated by DOP, DOC, DON, pH and average depth to water table.The abundance of high trophic level testate amoeba species (shell-aperture over their body size >0.20; i.e. primarily predators of protists and micro-metazoa) as well as the community size structure increased from lowest to highest elevation (respectively by 3.7× and 6×) and followed the seasonal patterns of total density, while DOC, DON, and DOC/DON decreased with elevation.These results agree with previously reported alteration of peatland microbial food chains in response to experimental warming, suggesting that climate-induced changes in microbial community structure (here a shortening of microbial food chains) represent a mechanism controlling the carbon balance of peatlands.

Growth variations and heritabilities of teak CSO-derived families and provenances planted in two humid tropical sites

Sixteen families derived from a clonal seed orchard (CSO) and 10 "provenances" (Prov) of teak (Tectona grandis) were tested in two different sites to be compared with respect to their growth performances. Both sites were located in Sabah, East Malaysia, under 2,500 mm of annual rainfall and no distinct dry season. The land in Taliwas was flat but prone to waterlogging. In Luasong, the soil was more hilly, acidic, and less fertile, though deeper. Nearly 9 years after planting, the two classes of genetic entries showed significant differences for height (P = 0.0002) and diameter at breast height (DBH) and volume (P < 0.0001) for the two sites combined. The superiority of the CSO families compared with the Prov class was more obvious in Luasong with averages of 18.0 vs 15.2 m (+18.6 %) for height, 18.1 vs 15.1 cm (+20.2 %) for DBH, and 0.179 vs 0.107 m(3) for individual tree volume (+67.9 %), as against 17.4 vs 15.7 m (+11.2 %), 19.1 vs 16.8 cm (+13.5 %), and 0.176 vs 0.126 m(3) (+40.3 %), respectively, in Taliwas. The CSO families were also more prone to site interaction for height (P = 0.004) and, to a lesser extent, for volume (P = 0.017) than the "Prov" (P = 0.030 and P = 0.057, respectively). Narrow-sense heritabilities estimated for the 16 CSO families across the two sites were lower for DBH (0.17) and volume (0.23) than for height (0.38). Type B genetic correlations suggested also higher site x families interactions for height (r (B) = 0.28).

Correlation of bone marrow micrometastases with nodal status in gastrointestinal tumors.

e14518 Background: Presence of bone marrow (BM) micrometastases (M) is a prognostic factor for patients (pts) with solid tumors. Sentinel lymph node (SLN) mapping (M) has been found to upstage pts with gastrointestinal (GI) cancers. However, a direct correlation between the presence of BMM and nodal metastases (mets) is lacking. A retrospective study was done to determine the relationship between BMM and nodal status in GI cancers. Methods: A total of 385 consecutive pts with GI cancers were studied. Pts underwent bilateral posterior-superior-iliac-spine BM aspiration. A highly sensitive staining method was used to differentiate cytokeratin postitive cells of epithelial origin from normal hematopoetic cells. Cytospin slides were stained wtih monoclonal anti-CAM 5.2 antibody. Visualization was achieved with Ventana view-Red detection system. Slides were then counterstained with haematoxylin. Automated Cellular Imaging System was used to classify cells of interest by cellular color, size and shape. SLNM was done by peritumoral injection of 1% methylene blue in the subserosal layer. Results: A total of 385 pts were analyzed. Of these 11% were found to have BMM. The three highest sites of BMM were cholangiocarcinoma 33%, Stomach 22% and esophagus 13% (Table 1A). BMM was +ve bilaterally in 44% of pts, unilaterally in 56%. In pts who underwent SLNM, BMM were detected in 8.3% of SLN +ve vs. 12% for SLN -ve pts. For a subgroup of pts with colorectal cancer undergoing SLNM, BMM were detected in 9.6% of SLN +ve pts vs. 11% for SLN -ve pts. Conclusions: BMM did not correlate with nodal status for GI malignancies suggesting a possible different mechanism for metastases. Detection of BMM may have a significant clinical value in SLN negative pts who may benefit from adjuvant therapy. [Table: see text] [Table: see text]

Forces driving the composition of butterfly assemblages in Andorra

Despite the impact that human presence has on the area, Andorra in the eastern Pyrenees still harbours a rich butterfly fauna and is a potentially excellent area for studying the effects of global change on biodiversity. The aim of this study was to identify and understand the factors that are inducing observed patterns of butterfly richness in Andorra. We used data collected between 2006 and 2010 from six transects of the Andorran Butterfly Monitoring Scheme that lie at heights from 1,000 to 2,400 m a.s.l. These transects are divided into 44 discrete sections and during the study period 18,603 individuals belonging to 126 butterfly species were recorded. The effects of elevation and habitat composition on species richness and abundance were analyzed, as was the presence of spatial structure in the butterfly assemblages. We found a clear tendency for species richness to decrease as elevation increased and also identified a major faunal turnover. Habitat composition seems to have little effect on species richness and butterfly abundance. A spatial structure was observed in the dataset, with a positive spatial autocorrelation at section scale that reflects a clear effect of altitudinal gradient on species assemblages. Finally, a cluster analysis enabled us to define two main faunistic groups, corresponding to lower (generally in closed habitats) and higher sites (generally in subalpine meadows and grasslands). We thus conclude that the elevation gradient is the principal factor driving butterfly distribution and abundance in Andorra.

Convergent space–time tree regeneration patterns along an elevation gradient at high altitude in the Alps

In most mountain regions forests growing at high altitude have fundamental ecological roles and other benefits to humans. A key factor affecting the structure and evolution of these forest stands is the spatial and temporal dynamics of natural regeneration. Sound empirical knowledge is therefore important to support management prescriptions aimed at guaranteeing the space and time continuity of the forest cover through proper natural regeneration.By means of a spatial distribution and structure analysis in three 1-ha permanent plots along an elevation gradient at high altitude, we assessed the small-scale processes and interaction between canopy cover and regeneration establishment in a temperature limited environment. Particular attention has been paid to the interaction among three tree species (Larix decidua, Picea abies and Pinus cembra) and their specific regeneration behaviour.The spatial pattern of regeneration is very similar in all the tree stands in spite of the increasingly limiting environmental conditions with elevation and the significant differences at species and stand level. On the contrary, the small-clustered organization of individuals, typical of a high elevation area, only becomes visible at the highest sites considering the age spatial structure.Significant differences in stand structure, composition and history in addition to differences in species autoecology, mode and strategy of seed dispersal and growth are not enough to result in parallel differences in the distribution patterns of regeneration. Given that successful regeneration is one of the most significant bottlenecks for high elevation forest maintenance, any management approach should take this into account in order to better sustain the future stand structure and dynamics with likely future changes in environmental conditions.

Abstract 315: Feasibility of outpatient ambulatory ECG monitoring to screen for silent atrial fibrillation: Pilot Findings from Screening Trial for Undiagnosed Atrial Fibrillation (STUDY-AF)

INTRODUCTION: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, accounting for up to one in five strokes. Identification of silent AF could reduce the total burden of stroke, particularly with newer, low-cost noninvasive methods of screening. We therefore performed a pilot study of ambulatory ECG monitoring to screen for AF. METHODS: We performed a prospective screening study by enrolling patients from May 2012 to January 2013 in outpatient clinics for cardiology, echocardiography, and stress testing at the VA Palo Alto Health Care System. Patient inclusion criteria were age ≥ 55 years and at least two of the following risk factors: coronary disease, congestive heart failure (CHF), hypertension, diabetes, and sleep apnea. We excluded patients with 1) a history of AF, supraventricular tachycardia, stroke, transient ischemic attack, systemic embolism, implantable pacemaker or defibrillator; 2) palpitations or syncope in the prior year. All patients received a small, wearable patch-based ambulatory ECG monitoring device (Zio® Patch, iRhythm Inc., San Francisco, CA) for up to two weeks of uninterrupted monitoring. The primary outcome was proportion of patients with AF. Secondary outcomes were prevalence of sustained and non-sustained ventricular tachycardia (NSVT) and supraventricular tachycardia (SVT). RESULTS: Among 57 patients (age 68 ± 7.4 years, 0% women), 53 (93%) completed ambulatory monitoring. The highest sites of enrollment were in cardiology clinic (47%) and echocardiography (46%). Atrial fibrillation was detected in three subjects (5.7%), who had a mean AF Burden of 4.2%. Common asymptomatic arrhythmias detected were SVT of ≥ 4 beats (N=37; 70%), ≥ 8 beats (N=24; 45%), and ≥ 60 seconds (N=4, 7.5%). Asymptomatic NSVT of ≥ 4 beats (N=16; 30%) and ≥ 8 beats (N=5, 9.4%) were also detected. CONCLUSION: Ambulatory screening of asymptomatic arrhythmias using the Zio® Patch is feasible; however the diagnostic yield for silent AF may be low, even among patients with established AF risk factors. Our study found a high prevalence of incidental asymptomatic SVT and NSVT. A larger trial with more targeted enrollment may be required to demonstrate the value of screening for AF. The impact of detecting incidental NSVT or SVT, which themselves could prompt evaluation and may be relevant to development of AF, requires further investigation.

Fungal root pathogen (Heterobasidion parviporum) increases drought stress in Norway spruce stand at low elevation in the Alps

Tree-ring patterns of Picea abies (L.) Karst. both unaffected and affected by Heterobasidion parviporum were analysed in three mature stands located at different elevations in the Eastern Alps. The main objectives were (1) to clarify the role of climatic conditions on infected trees; (2) to estimate indirect volume losses due to the prolonged presence of the fungus within the wood. The low elevation site showed the highest growth decline in the last decade, whereas all infected trees at medium and high elevation showed a slow growth decline over many decades. We hypothesise that infection could be dated over 80 years at the highest site. Fungal attack made P. abies more susceptible to drought stress at low elevation site. Both infected and healthy P. abies at medium and high elevation showed similar climate–growth relationships, suggesting that the same driving environmental factors influence their growth. At low elevation, H. parviporum was seemingly more aggressive, causing a more rapid decline, decreasing the ability of host trees to cope with drought and, in some cases, inducing cambial activity to stop. P. abies at higher elevation, however, exhibited a very slow decline and no sign of increasing water stress since the influence of climate on tree growth was the same for both infected and healthy trees.

An overview of black carbon deposition in High Asia glaciers and its impacts on radiation balance

Since 2000, 18 High Asia glaciers have been surveyed for black carbon (BC) deposition 22 times, and numerous snow samples and ice cores have been collected by researchers. However, most of the results were interpreted individually in papers. Here, we assemble the data and discuss the distribution of BC deposition and its impacts on the melting of the glaciers through radiative forcing. We find that BC distribution on the surfaces of High Asia glaciers primarily depends upon their elevations (i.e., higher sites have lower concentrations) and then upon regional BC emissions and surface melting conditions. BC concentrations in High Asia glaciers are similar to the Arctic and western American mountains but are significantly less than heavy industrialized areas such as northern China. Although Himalayan glaciers, which are important due to their water resources, are directly facing the strong emissions from South Asia, their mean BC is the lowest due to high elevations. A new finding indicated by ice core records suggested that great valleys in the eastern Himalayan section are effective pathways for BC entering the Tibetan Plateau and make increasing BC trends in the local glaciers. On average, BC deposition causes a mean forcing of ∼6 Wm−2 (roughly estimated 5% of the total forcing) in High Asia glaciers and therefore may not be a major factor impacting the melting of most glaciers.

Quantification of cloud water interception along the windward slope of Santa Cruz Island, Galapagos (Ecuador)

The Galapagos Archipelago is nearly devoid of freshwater resources, but during six months of the year, a fog layer covers the windward slopes of the main islands. In order to investigate the hydrological importance of this phenomenon, a monitoring network was set up on Santa Cruz Island, at the center of the archipelago. Meteorological parameters were monitored together with throughfall and stemflow at two stations: a first in a secondary forest at the lowest fringe of the fog layer (400ma.s.l.), and a second in shrub lands of the Galapagos National Park, at the center of the fog layer (650ma.s.l.). Cloud water interception was quantified from the wet canopy water budget, based on a modified Rutter-type canopy interception model. This methodology allowed the estimation of fog interception for short time intervals (15min) and avoided the subjective separation into individual rainfall events. Fog was found to be a negligible water input at the lower site, but was estimated at 26±16% of incident rainfall at the higher site. Wind was shown to enhance fog interception, but this alone could not explain the difference in fog catch between the two sites. Higher liquid water content and more frequent fog occurrence contributed to the difference as well. This study highlights that the presence of fog may induce a marked increase of net precipitation, but this effect is restricted to the summit areas exposed to winds, located in the center of the cloud belt.

Simulating Site-Specific Effects of a Changing Climate on Jack Pine Productivity Using a Modified Variant of the CROPLANNER Model

This study evaluated the site-specific effects of projected future climate conditions on the productivity of jack pine (Pinus banksiana Lamb.) plantations over the next 50 years (2011-2061). Climatic parameters as predicted by the Canadian Global Climate Model in association with a regional spatial climatic model, under 3 emissions scenarios (no change (NC), B1 and A2), were used as input values to a biophysical-based site-specific height-age model that was integrated into the CROPLANNER model and associated algorithm. Plantations managed under a basic silvicultural intensity on two site qualities at each of two geographically separated sites (northeastern and northwestern Ontario, Canada) were assessed. The results indicated that the stands situated on low-to-medium quality sites at both locations were largely unaffected by the predicted increase in temperature and precipitation rates. Conversely, however, stands situated on good-to-excellent quality sites grown under the B1 and A2 scenarios experienced consequential declines in stand development rates resulting in decreases in rotational mean sizes, biomass yields, recoverable end-product volumes, and economic worth. In addition to providing a plausible range of site-specific climate change outcomes on jack pine productivity within the central portion of the species range, these results suggest that future predictions that do not account for potential climate changes effects may overes- timate merchantable productivity on the higher site qualities by approximately 15%. As demonstrated, in- corporating biophysical-based site index functions within existing forest productivity models may repre- sent a feasible approach when accounting for climate change effects on yield outcomes of boreal species.

Chemical Composition of PM10 and PM2.5 Collected at Ground Level and 100 Meters during a Strong Winter-Time Pollution Episode in Xi'an, China

ABSTRACT An intensive sampling of aerosol particles from ground level and 100 m was conducted during a strong pollution episode during the winter in Xi'an, China. Concentrations of water-soluble inorganic ions, carbonaceous compounds, and trace elements were determined to compare the composition of particulate matter (PM) at the two heights. PM mass concentrations were high at both stations: PM10 (PM with aerodynamic diameter ≤10 μm) exceeded the China National Air Quality Standard Class II value on three occasions, and PM2.5 (PM with aerodynamic diameter ≤2.5 μm) exceeded the daily U.S. National Ambient Air Quality Standard more than 10 times. The PM10 organic carbon (OC) and elemental carbon (EC) were slightly lower at the ground than at 100 m, both in terms of concentration and percentage of total mass, but OC and EC in PM2.5 exhibited the opposite pattern. Major ionic species, such as sulfate and nitrate, showed vertical variations similar to the carbonaceous aerosols. High sulfate concentrations indicated that coal combustion dominated the PM mass both at the ground and 100 m. Correlations between K+ and OC and EC at 100 m imply a strong influence from suburban biomass burning, whereas coal combustion and motor vehicle exhaust had a greater influence on the ground PM. Stable atmospheric conditions apparently led to the accumulation of PM, especially at 100 m, and these conditions contributed to the similarities in PM at the two elevations. Low coefficient of divergence (CD) values reflect the similarities in the composition of the aerosol between sites, but higher CDs for fine particles compared with coarse ones were consistent with the differences in emission sources between the ground and 100 m. IMPLICATIONS An intensive observation of aerosol particles from ground level and 100 m during a winter-time pollution episode in Xi'an, China, showed that PM levels often greatly exceeded national standards. High concentrations of sulfate indicated that emissions from coal combustion dominated the PM mass both at the ground and at 100 m. No dramatic differences in PM or chemical species loadings were found between the different elevations, and this was most likely due to relatively stable meteorological conditions. Nevertheless, the data suggested greater impacts from fresh emissions at the ground site and more particle aggregates and a stronger influence from biomass burning at the higher site. The results imply that monitoring programs need to take this variability into account. The air quality in Xi'an would be improved by reducing the emissions from coal and biomass burning.

Cushions of Thylacospermum caespitosum (Caryophyllaceae) do not facilitate other plants under extreme altitude and dry conditions in the north-west Himalayas

Cushion plants are commonly considered as keystone nurse species that ameliorate the harsh conditions they inhabit in alpine ecosystems, thus facilitating other species and increasing alpine plant biodiversity. A literature search resulted in 25 key studies showing overwhelming facilitative effects of different cushion plants and hypothesizing greater facilitation with increased environmental severity (i.e. higher altitude and/or lower rainfall). At the same time, emerging ecological theory alongside the cushion-specific literature suggests that facilitation might not always occur under extreme environmental conditions, and especially under high altitude and dryness. To assess these hypotheses, possible nursing effects of Thylacospermum caespitosum (Caryophyllaceae) were examined at extremely high altitude (5900 m a.s.l.) and in dry conditions (precipitation <100 mm year(-1)) in Eastern Ladakh, Trans-Himalaya. This is, by far, the highest site, and the second driest, at which the effects of cushions have been studied so far. In accordance with the theoretical predictions, no nursing effects of T. caespitosum on other alpine plants were detected. The number and abundance of species were greater outside cushions than within and on the edge of cushions. None of the 13 species detected was positively associated with cushions, while nine of them were negatively associated. Plant diversity increased with the size of the area sampled outside cushions, but no species-area relationship was found within cushions. The results support the emerging theoretical prediction of restricted facilitative effects under extreme combinations of cold and dryness, integrating these ideas in the context of the ecology of cushion plants. This evidence suggests that cases of missing strong facilitation are likely to be found in other extreme alpine conditions.

Comparison of ozone concentrations on a surface elevation gradient with balloon-borne ozonesonde measurements

Ambient ozone data collected on a ground-level elevation transect in the Colorado Front Range Mountains, spanning an elevation range from 1660 m above sea level (ASL) to 3530 m ASL, were compared to vertical ozonesonde measurements obtained from a National Oceanic and Atmospheric Administration (NOAA) launch site located just a few kilometers from the lowest elevation site on the surface site elevation transect. Ozonesondes were launched approximately weekly throughout the one-year monitoring period from September 1, 2007 to August 31, 2008, and daily from June 27 to July 11, 2008. Ozonesonde profile data were found to display a variable agreement with the data from the surface sites along the elevation transect. The strongest determinants of the ozone profile behavior were found to be the vertical atmospheric potential temperature profile and season. The surface elevation ozone profile generally matched the sonde profile quite well, capturing all of the same major features. A seasonal relationship for surface–ozonesonde concentration differences was found. This difference is smallest in winter and spring, and tends to be slightly positive (i.e. higher ozone at surface sites), with three-month seasonal median values up to 4 ppbv. The difference turns negative (i.e. lower ozone at surface sites) in summer–fall, with seasonal median values becoming as large as −13 ppbv. The seasonal cycle in surface–ozonesonde differences was minimal for the lowest monitoring site at 1660 m ASL. The magnitude of seasonal change increased with elevation to a maximum of 22 ppbv at 3350 m ASL, before then dropping again by more than half at the highest site, which, at 3530 m ASL, is frequently above the mixed layer boundary. Seasonally dependent surface processes, including ozone production in the surface layer and deposition processes are the most likely determinants of seasonal variation in the surface–ozonesonde data relationship. ► One year of surface and balloon-borne ozone measurements along a ∼2000 m elevation transect in the Colorado Rocky Mountains. ► There generally was good agreement in the two data sets. ► Deviations between the two data sets show a seasonal and altitude dependence.

The spider genus Chrysometa (Araneae, Tetragnathidae) from the Pico da Neblina and Serra do Tapirapecó mountains (Amazonas, Brazil): new species, new records, diversity and distribution along two altitudinal gradients

Eight new species of the spider genus Chrysometa Simon, 1894 (Araneae, Tetragnathidae) are described and illustrated. Chrysometa nubigena n. sp., C. waikoxi n. sp., C. petrasierwaldae n. sp., C. santosi n. sp., C. yanomami n. sp., C. candianii n. sp., C. lomanhungae n. sp., and C. saci n. sp. Those species were collected in a study on the diversity of spider communities along altitudinal gradients in Brazilian Amazonia. C. saci was captured at the Serra do Tapirapecó (Barcelos), while all the other species are from the Pico da Neblina (São Gabriel da Cachoeira), the highest mountain in Brazil. We provide new records for C. boraceia, C. flava, C. guttata, C. minuta and C. opulenta, and we describe the male of C. minuta for the first time. We also present the first results on the diversity and altitudinal distribution of the species of Chrysometa at the Pico da Neblina and Serra do Tapirapecó. We sampled the first locality at six different elevations, and obtained 336 specimens distributed in 12 species. Richness and abundance, as well as relative importance peaked at the highest sites sampled (2,000 and 2,400 m). The three most abundant species showed a segregated distribution, being dominant or exclusively distributed in different altitudes. At the Serra do Tapirapecó, sampling at four different elevations up to 1200 m, we only obtained 40 individuals divided in four species, and there was no clear relation to altitude. Most of the new species were found at mid and high altitude sites, while species from lower altitude sites represented widespread species. The comparison with other neotropical spiders inventories highlights the high diversity recorded at Pico da Neblina, which could be assigned to the large environmental variation covered in this work and to the sampling of high-altitude environments. Inventories in the Andean region and other information in the literature also seem to support the association of Chrysometa with high altitude environments.

High-resolution study of layering within the percolation and soaked facies of the Greenland ice sheet

AbstractWithin the percolation and soaked facies of the Greenland ice sheet, the relationship between radar-derived internal reflection horizons and the layered structure of the firn column is unclear. We conducted two small-scale ground-penetrating radar (GPR) surveys in conjunction with 10 m firn cores that we collected within the percolation and soaked facies of the Greenland ice sheet. The two surveys were separated by a distance of ~50 km and ~340m of elevation leading to ~40 days of difference in the duration of average annual melt. At the higher site (~1997ma.s.l.), which receives less melt, we found that internal reflection horizons identified in GPR data were largely laterally continuous over the grid; however, stratigraphic layers identified in cores could not be traced between cores over any distance from 1.5 to 14.0 m. Thus, we found no correlation between firn core stratigraphy observed directly and radar-derived internal reflection horizons. At the lower site (~1660ma.s.l.), which receives more melt, we found massive ice layers &gt;0.5m thick and stratigraphic boundaries that span &gt;15m horizontally. Some ice layers and stratigraphic boundaries correlate well with internal reflection horizons that are laterally continuous over the area of the radar grid. Internal reflection horizons identified at ~1997ma.s.l. are likely annual isochrones, but the reflection horizons identified at ~1660ma.s.l. are likely multi-annual features. We find that mapping accumulation rates over long distances by tying core stratigraphy to radar horizons may lead to ambiguous results because: (1) there is no stratigraphic correlation between firn cores at the 1997 m location; and (2) the reflection horizons at the 1660m location are multi-annual features.

Colonization and demographic structure ofDeschampsia antarcticaandColobanthus quitensisalong an altitudinal gradient on Livingston Island, South Shetland Islands, Antarctica

The colonization capacity and demographic structure of populations of Deschampsia antarctica and Colobanthus quitensis were studied in different microhabitats between 10 and 147 m a.s.l. on Livingston Island, South Shetland Islands, near the Spanish Antarctic base Juan Carlos I, in February 2002. At the highest site (147 m a.s.l.), mean temperatures were about 1 ÂoC lower than at sea level. Both species are less common in inland areas and at the highest altitudes only occur at restricted sites that are frequently snow-free in the early austral summer. The diameters of the largest plants ( C. quitensis cushions 7-8 cm ; D. antarctica tufts 10-11 cm) in the populations growing at the highest altitudes (110 and 147 m a.s.l.) suggest that these populations were established about 24-28 years ago. The largest diameter plants ( Deschampsia 20 cm; Colobanthus 18 cm) were found at the lowest altitudes on deep soil. The presence of numerous seedlings and young individuals on the periphery of populations established several years ago or at recently colonized sites suggests an active process of expansion. There were more emerged seedlings of C. quitensis than of D. antarctica , but the density of established individuals was higher for D. antarctica , suggesting these species have different demographic strategies. Keywords: Antarctic vascular plants; altitude and habitat effect; colonization; population structure (Published: 13 May 2011) Citation: Polar Research 2011, 30 , 7146, DOI: 10.3402/polar.v30i0.7146

Ovipositional Behavior in the Context of Mass Rearing of Anopheles arabiensis

Large-scale production of mosquitoes is a key factor for a successful sterile insect technique program. A manageable mass-production cage must contain appropriate features for adult resting, mating, feeding, and ovipositional activities. In order to maximize egg collections, tests were conducted to determine the physical characteristics of ovipositional sites for caged Anopheles arabiensis. Effects of texture, shade, height, and shape of the ovipositional container on female behavior were investigated. Results indicate a strong preference for oviposition on humid substrates over free-standing water. The shade and texture of the cup's walls also influenced site choice, with black rough inner vertical walls of the cup resulting in the largest number of eggs. Ovipositional sites with square shape were preferred rather than circular cups, and in the square cups, >60% of the eggs were laid in the corners. Height also affected oviposition, as An. arabiensis significantly favored the lowest sites even though some oviposition occurred at higher sites. Based on this study and from available literature, we determined the characteristics of an artificial ovipositional site that includes all these characteristics, which will yield large numbers of eggs required for mass production of this species.

Ichneumonid (Hymenoptera) parasitoids of overwintering Hyphantria cunea (Drury) (Lepidoptera: Arctiidae) pupae in hazelnut plantations of the central Black Sea region of Turkey

Overwintering pupae of the phytophagous lepidopteran pest Hyphantria cunea (Drury) (Lepidoptera: Arctiidae) were collected from 38 hazelnut (Corylus avellana L.) plantations in Samsun province, Turkey. Five species of ichneumonids, Virgichneumon dumeticola (Gravenhorst), V. albilineatus (Gravenhorst), Enicospilus ramidulus (L.), Pimpla rufipes (Miller) and one Gelis sp. were reared. Average parasitism was 0.13% and 2.33% for 2008 and 2009, respectively. Highest site parasitism was 14.9% and highest site diversity was 4 species. Virgichneumon dumeticola was the commonest species, with 73% of the total speciments. Virgichneumon albilineatus and E. ramidulus are reported for the first time from H. cunea, and V. albilineatus is also reported for the first time from Turkey. Gelis sp. is reported for the first time as a parasitoid of H. cunea in Turkey.

Modelling the evolutionary effects of a coastal marine reserve on different ecological guilds of fish

Marine reserves are used as a management tool to ensure sustainability of fish stocks. Using an individual-based model, we compare the evolutionary effect of a reserve located on a nursery ground, spawning ground, feeding ground, or in a year-round habitat for sedentary species. We model the evolution of life-history traits, specifically size at maturation and site fidelity. Within species, individuals will differ in the time spent within a reserve depending on their patterns of movement and migration. We predict that the evolutionary effect of fishing depends not only on the survival probability but also on the life-history stages primarily affected by high harvest mortality. Protection against evolution to small maturation size is most effective where a reserve protects a sedentary population or protects the feeding grounds of a population. We also find that protection of the feeding ground of an anadromous stock such as Atlantic salmon may lead to local adaptation enhanced by evolution of higher site fidelity, similar to protection of a sedentary species.