Average Annual Density Research Articles

국내 서식하는 뉴트리아(Myocastor coypus)의 형태측정 및 비교에 관한 연구

The nutria(Myocastor coypus) that is originated from South America is a representative Invasive alien species in Korea. invasive alien species is one of the biggest causes for the loss of biodiversity and it may threaten the conservation and function of ecology as well as the welfare of mankind. Intense habitation has been made around the Nakdong River basin area that this study has analyzed the habitat density of nutria for the subject of 3 survey sites in the Nakdong River basin area. As a result of survey on habitation density in 2011 and 2012, under St.1 it was shown <TEX>$2.01{\pm}0.21$</TEX>/ha in 2011 and <TEX>$0.69{\pm}0.55$</TEX>/ha in 2012. Under St.2, it was shown <TEX>$0.91{\pm}0.37$</TEX>/ha in 2011 and <TEX>$0.55{\pm}0.39$</TEX>/ha in 2012. Under St.3, it was shown <TEX>$5.31{\pm}0.72$</TEX>/ha in 2011 and <TEX>$3.99{\pm}2.31$</TEX>/ha in 2012. The wet survey areas of St.1 and St.3 had shown relatively high habitation density compared to St. 2, the river survey area, and the average annual habitation density of the survey area was <TEX>$2.74{\pm}2.29$</TEX>/ha in 2011 and <TEX>$1.74{\pm}1.18$</TEX>/ha in 2012 that it has shown slightly reducing trend. As a result of measuring the morphology by capturing the habitation individuals, the average body length of adults is <TEX>$92.23{\pm}9.41cm$</TEX>, the length from the head to body for <TEX>$53.90{\pm}5.15cm$</TEX>, tail length for <TEX>$38.33{\pm}4.83cm$</TEX>, hind foot length for <TEX>$13.82{\pm}1.00cm$</TEX>, front foot length for <TEX>$6.02{\pm}0.56cm$</TEX>, and weight for <TEX>$5.48{\pm}1.08kg$</TEX>. As a result of comparing the types between genders, male showed a slightly higher figure in all parts compared to female and it showed significantly difference in total body length, head-body length, front foot length and total weight. As a result of analysis for each head-body length, other measured parts, weight and relativity for each measured part, all bodily part is shown to have the higher volume of correlations. The condition index of individuals in the survey area was shown in the average of <TEX>$35.67{\pm}4.78$</TEX> with female for an average of <TEX>$36.60{\pm}5.19$</TEX> and male for an average of <TEX>$34.73{\pm}4.34$</TEX>. The winter temperature in the southern area of Korea is considered for not greatly impacting on the habitation and development of nutria that, if there is no artificial control, it is considered to have certain concern of showing drastic breeding and territory expansion for the habitation group.

Developing Truck Corridor Crash Severity Index

According to NHTSA, more than 400,000 truck accidents occurred in 2009 and approximately 7,800 of those were fatal crashes. Compared with extensive studies conducted on freeway truck safety, the research on arterial streets is considerably disproportionate. Making the connections between truck traffic generators, arterial streets are key links in door-to-door deliveries. There is an urgent need to study truck safety on arterial streets because of the strong growth of truck traffic. Truck-related crashes are expected to be reduced through careful planning of the location, design, and operation of driveways, median openings, street connections, and street sections. Through the collection of extensive data on selected arterial corridors that are heavily used by trucks, contributing factors to truck crash frequency and severity were identified with a negative binomial model and multinomial logit model. Corridor truck miles traveled, annual average daily traffic, signal density, shoulder width, and pavement serviceability index and its standard deviation are significant factors for crash frequency prediction. The multinomial logit model identified 12 causal factors for crash severity, such as posted speed limit, lane width, number of lanes, pavement condition index, and undivided roadway portion. Subsequently, a crash severity index for truck arterial corridors was developed. The findings from the study not only will benefit state and local agencies in planning, design, and management of a safer truck arterial corridor, but will also help carriers to optimize their routes from a safety perspective.

Aquatic Oligochaetes of Iraq's Southern Marshes

Aquatic Oligochaetes community in the Iraqi southern marshes, Al- Hawiezah, Al-Chibayish and Al-Hammar, have been studied for the period from July 2006 to June 2007. Two sites within each marsh, in addition to a reference site located at Shatt Al-Garma, have been chosen for sample collection using Ekman dredge. The results revealed that the highest average annual density was 16800 individual / m2 recorded in Al-Hawiezah marsh, while in Al-Chibayish and al-Hammar marsh the density did not exceed 5111 individual/m2. In contrast, the density of Oligochaetes recorded in Shatt Al-Garma was about 10500 individual / m2. The highest monthly density was recorded in April 2007.The highest local percentage occurrence was 96% recorded in Al-Hawiezah marsh, while the highest average monthly percentage occurrence was recorded in January 2007.The study revealed the presence of 19 Oligochaetes species belonging to 14 genera and 4 families. Naididae was represented by 8 spp.; Tubuficidae 8 spp.; Lumbriculidae 2 spp. and Lumbricidae 1 spp. Tubificid worms formed about 73% of the total count while Naididae formed 15%, Lumbriculidae 8% and Lumbricidae 4%.Among Tubificidae, Limnodrilus was the most abundant genus composed about 35% of L. hoffmeisteri; 11.5% L. claparedianus; 8% L. profundicola and 4.7% L. maumeensis, followed by Tubifex tubifex 23%. Other species were Branchuira sowerbyi formed 15%; 2.8 and 2 % for Peloscolex velutinus and Aulodrilus pigueti respectively. Naididae worms comprised 8 species including 32% of Dero digitata, 24% of Nais variabilis, 14% of Amphichaeta sp. and 11% of each of D.obtuse and Pristina longiseta. However, D. dorsalis represented only 7.5% of the total Naididae. Few individuals of B. sowerbyi and Lumbriculus variegates, with two regenerated parts at the posterior end were also detected in some samples. This case was considered a rare observation within the population of these worms in this particular area.

Aquatic Oligochaetes of Iraq's Southern Marshes

Aquatic Oligochaetes community in the Iraqi southern marshes, Al- Hawiezah, Al-Chibayish and Al-Hammar, have been studied for the period from July 2006 to June 2007. Two sites within each marsh, in addition to a reference site located at Shatt Al-Garma, have been chosen for sample collection using Ekman dredge. The results revealed that the highest average annual density was 16800 individual / m2 recorded in Al-Hawiezah marsh, while in Al-Chibayish and al-Hammar marsh the density did not exceed 5111 individual/m2. In contrast, the density of Oligochaetes recorded in Shatt Al-Garma was about 10500 individual / m2. The highest monthly density was recorded in April 2007.The highest local percentage occurrence was 96% recorded in Al-Hawiezah marsh, while the highest average monthly percentage occurrence was recorded in January 2007.The study revealed the presence of 19 Oligochaetes species belonging to 14 genera and 4 families. Naididae was represented by 8 spp.; Tubuficidae 8 spp.; Lumbriculidae 2 spp. and Lumbricidae 1 spp. Tubificid worms formed about 73% of the total count while Naididae formed 15%, Lumbriculidae 8% and Lumbricidae 4%.Among Tubificidae, Limnodrilus was the most abundant genus composed about 35% of L. hoffmeisteri; 11.5% L. claparedianus; 8% L. profundicola and 4.7% L. maumeensis, followed by Tubifex tubifex 23%. Other species were Branchuira sowerbyi formed 15%; 2.8 and 2 % for Peloscolex velutinus and Aulodrilus pigueti respectively. Naididae worms comprised 8 species including 32% of Dero digitata, 24% of Nais variabilis, 14% of Amphichaeta sp. and 11% of each of D.obtuse and Pristina longiseta. However, D. dorsalis represented only 7.5% of the total Naididae. Few individuals of B. sowerbyi and Lumbriculus variegates, with two regenerated parts at the posterior end were also detected in some samples. This case was considered a rare observation within the population of these worms in this particular area.

Phytoplankton Species Composition and Abundance in the Southwestern Caspian Sea

This study, accomplished is focused on the spatial and temporal distribution and species composition of phytoplankton in the southwestern Caspian Sea between January 2008 and December 2008. Samples were collected from 11 stations along three transects known as Lisar, Anzali and Sefidrood. This study identified 43 phytoplankton species comprised of diatoms (25 species), dinoflagellates (7 species), chlorophytes (6 species), cyanophytes (4 species), and euglenoids (1 species) were identified. The study showed, diatom Dactyliosolen fragilissimus and the dinofllagelate Prorocentrum cordatum numerically dominate the southwestern Caspian Sea. The annual average phytoplankton density was calculated as 2.35E+04 ± 1.63E+04 Cell L-1, with the maximum value recorded in the winter (4.50E+04 ± 3.90E+04 Cell L -1 ). Diatoms were dominant during the autumn and winter (77.0% and 96.0%, respectively), while dinoflagellates were prevalent during the spring and summer (89.0% and 86.0%, respectively). The annual average chlorophyll a was calculated as 9.26±3.54 μg L -1 , with the maximum values were recorded in the winter (16.9±5.60 μg L-1). This is supported by the Spearman rank correlation result between phytoplankton abundance and chlorophyll a (r=0.551). The high phytoplankton cell density and chlorophyll a concentration coincided with the poor species composition.

Foraging behavior and prey of sea otters in a soft- and mixed-sediment benthos in Alaska

Sea otter (Enhydra lutris kenyoni) foraging behavior and prey preference were studied from June to August 2001–2004 in Simpson Bay, Prince William Sound, Alaska. The study area has an average water depth of 30m and a benthos primarily of soft- and mixed-sediment with no canopy-forming kelps. A total of 1816 foraging dives from 211 bouts were recorded. Overall, dives ranged in depth from <5 to 82m; most dives were less than 15m (40%) with smaller, secondary peaks at 25–30m (10%) and 50–55m (7%). Average dive depth and duration were 27m±19.5 and 1.89min±0.88, respectively. Dive durations were all significantly different: male>unknown>female. Dive depths reflected the bathymetry (percentage of the bay within a depth range) of Simpson Bay but favored shallow areas. 87% of foraging dives were successful, and 44% of the prey was positively identified: 75% clams, 9% Pacific blue mussels, 6% crabs, 2% Reddish scallops and a variety of other invertebrates. There was no evidence for prey specialization among the sexes. Although sea otters in Simpson Bay rely heavily on bivalves, their diet has remained unchanged for the past 18 years, and the minimum summer population has been constant for at least the past nine years. It appears that bivalves are the predominant and stable component of the diet, and their productivity is sufficient to sustain a stable population of sea otters with a minimum peak summer density of 4.3 adult otters km−2 and an average annual density of ca. 2.9 adult otters km−2 for the past nine years and probably longer.

Rotifer community structure and assessment of water quality in Yangcheng Lake

Rotifer community structure was investigated in Yangcheng Lake in 2008. Dominant species and species diversity indices were determined and QB/T was used to assess water quality. The annual average density and biomass of the rotifers in Yangcheng Lake was 2 894 ± 1 006 ind./L and 12.47 ± 10.28 mg/L, respectively. The highest densities were observed in the western portion of the lake in March, but the highest biomass occurred in inflowing creeks in September. Within a year of monitoring in Yangcheng Lake, 93 species were identified and the dominant species were found to be Polyarthra trigla, Brachionus angularis, Keratella cochlearis, Keratella valga, Brachionus calyciflorus, and Filinia major. Of the species recorded, 75 were pollution indicator species. Density and biomass exhibited significant positive correlations with water temperature (R = 0.209, P = 0.003; R = 0.446, P = 0.000), but the peak density showed two lags in response to chl a. According to the Jaccard similarity index (SJ), the greatest similarity among dominant species occurred between creeks and the eastern part of the lake. The annual average Shannon-Wiener diversity index H′, Margalef richness index D and Pielou evenness index J were 1.96 ± 0.34, 1.61 ± 0.50 and 0.77 ± 0.10, respectively. In all four areas of Yangcheng Lake, β-mesosaprobic species comprised the largest share of pollution indicator species. These data suggest that Yangcheng Lake is mesosaprobic.

Temporal and spatial patterns of &lt;i&gt;Limnodrilus hoffmeisteri&lt;/i&gt; Clapar&amp;#232;de in Lake Taihu

2005年1-12月对太湖霍甫水丝蚓进行了逐月调查.太湖霍甫水丝蚓年均密度和生物量分别为3273.75 ind./m²和4.697 g/m²,均在2月份达到最大值.根据体长频数分布的周年变化,推测太湖霍甫水丝蚓一年有三代.太湖霍甫水丝蚓密度和生物量在空间上表现出明显的差异性,且随季节变化较小,其高值区域均出现在太湖北部梅梁湾和竺山湾及西部河口湖区,而在其它区域的现存量均较低.分析表明太湖霍甫水丝蚓空间差异可能与营养水平、底质类型、可摄食的食物及生境的稳定性等因素有关.;The population of Limnodrilus hoffmeisteri Claparède in Lake Taihu (Eastern China) was investigated in 2005 by monthly sampling. The annual average density and biomass of this worm were 3273.75 ind./m² and 4.697 g/m², respectively. Both population density and biomass peaked in February. According to the annual dynamics of the frequency distributions of body length, the species had three generations and reproduced in considerable time throughout the year. The results showed a strong clumped distribution pattern of L. hoffmeisteri but it changed little among seasons. The highest population density and biomass of L. hoffmeisteri were found in Meiliang Bay, Zhushan Bay and the river-mouths areas in the west, while other places of the lake had very low worm density. The key factors regulating this spatial distribution pattern may be nutrient state, types of substrate, food availability and habitat stability.

Temporal and spatial changes of fish biomass during the warm season in the Russian part of the elittoral of the Sea of Japan

Total biomass of fish in the Russian elittoral zone of the Sea of Japan during the warm period, according to surveys performed from 1983 to 2006, was 475.6 thousand tons, or 8.8 t/km2. Relatively high values of specific biomass were recorded in the 1980s, and the maximum value (29.2 t/km2) was recorded in 1986, reflecting the cooccurrence of dramatic surges in the Alaska pollock (Theragra chalcogramma) and the Pacific herring (Clupea pallasii). In the 1990s, the total biomass of fishes decreased by an order of magnitude, and over almost the entire decade remained approximately at the same level (4.5–6.7 t/km2); after 2001, this parameter never reached higher values than 4.4 t/km2. The average annual density of fish biomass varied in different areas from 5.8 t/km2 (northern Strait of Tartary) to 13.3 t/km2 (southern Primorskii krai). The principal factor determining the value of specific fish biomass in particular areas is the level of the Alaska pollock’s resources. In the elittoral, the highest concentration of the absolute majority of dominant and subdominant species are confined to the range of depths from 50 to 100 m.

Seasonal variations on community structures of rotifers in small lakes of an excavating coal subsidence region in Huaibei

2005年3月至2007年2月对淮北采煤塌陷区两个小型湖泊(南湖和乾隆湖)轮虫的群落结构进行了连续两年的调查.南湖共检测到轮虫9属14种,乾隆湖共计15属27种.乾隆湖轮虫年平均密度为1916 ind./L,约为南湖(198.4 ind./L)的近10倍.乾隆湖和南湖轮虫的最大密度分别为6915和1185 ind./L.在南湖和乾隆湖轮虫的季节动态中,冬、春季以前额犀轮虫为主,夏、秋季以多肢轮虫、异尾轮虫为主.在南湖,长肢多肢轮虫、暗小异尾轮虫和小链巨头轮虫分别占年平均密度的24.4%、24.0%和23.0%.在乾隆湖,暗小异尾轮虫、长肢多肢轮虫和裂痕龟纹轮虫分别占年平均密度的31.5%、27.2%和7.3%.南湖和乾隆湖轮虫的Shannon-Wiener指数范围分别为0~2.06和1.28~2.68,平均值分别为0.67和1.99.水温、营养盐和浮游植物生物量对淮北采煤塌陷区小型湖泊轮虫的群落结构具有重要影响.;The community structures of rotifers and their seasonal variations in small lakes (Lake Nanhu and Lake Qianlong,) in an excavating coal subsidence region in Huaibei city have been investigated from March 2005 to February 2007. A total of fourteen species have been recorded, belonging to nine genera in Lake Nanhu, and twenty-seven species belonging to fifteen genera in Lake Qianlong. Average density of rotifers in Lake Qianlong (1916 ind./L) is about 10 times higher than that in Lake Nanhu (198.4 ind./L). Maximum density of rotifers is 6915 ind./L in Lake Qianlong and 1185 ind./L in Lake Nanhu. Rhinoglena frontalis is dominant species in winter and spring, while Polyarthra spp. and Trichocerca spp. are dominant species in summer and autumn. Among annual average density of rotifers in Lake Nanhu, Polyarthra dolichoptera, Trichocerca pusilla and Cephalodella catellina are 24.4%, 24.0% and 23.0%, respectively. Among annual average density of rotifers in Lake Qianlong, Trichocerca pusilla, Polyarthra dolichoptera and Anuraeopsis fissa are 31.5%, 27.2% and 7.3%, respectively. The ranges of Shannon-Wiener indices in Lake Nanhu and Lake Qianlong are 0 2.06 and 1.28 2.68, with average values of 0.67 and 1.99, respectively. The community structures of rotifers in the small lakes of an excavating coal subsidence region in Huaibei city are influenced by water temperature, nutrients and phytoplankton biomass.

Land use/land cover change and driving force analysis in Xishuangbanna Region in 1986–2008

This article summarizes the change of land use in 1986–2008 through data analysis on land use/land cover in Xishuangbanna Region, Yunnan Province, China. The major driving forces of land use change are identified by the gray incidence analysis method. The results shows that the area ratio of forestland in Xishuangbanna Region decreased from 57.62% to 42.87% in the studied period, The ratio of plantation and shrub land increased from 4.77%, 15.10% to 13.92%, 23.87%, respectively, The ratio of crop land increased from 4.77% in 1986 to 5.85% in 1999, and then dropped to 4.99% in 2008. The driving force analysis shows that population density, the average annual temperature, grain output and economic density are among the major driving forces causing land use/land cover change (LUCC) in Xishuangbanna Region.

The Daily Cloud-to-Ground Lightning Flash Density in the Contiguous United States and Finland

A method is developed to quantify thunderstorm intensity according to cloud-to-ground lightning flashes (hereafter ground flashes) determined by a lightning-location sensor network. The method is based on the ground flash density ND per thunderstorm day (ground flashes per square kilometer per thunderstorm day) calculated on 20 km × 20 km fixed squares. Because the square size roughly corresponds to the area covered by a typical thunderstorm, the flash density for one square defines a unit thunderstorm for the purposes of this study. This method is tested with ground flash data obtained from two nationwide lightning-location systems: the National Lightning Detection Network (NLDN) in the contiguous United States and the portion of the Nordic Lightning Information System (NORDLIS) in Finland. The distribution of daily ground flash density ND is computed for all of Finland and four 800 000 km2 regions in the United States (identified as western, central, eastern, and Florida). Although Finland and all four U.S. regions have median values of ND of 0.01–0.03 flashes per square kilometer per thunderstorm day—indicating that most thunderstorms produce relatively few ground flashes regardless of geographical region—the most intense 1% of the storms (as measured by the 99th percentiles of the ND distributions within each region) show much larger differences among regions. For example, the most intense 1% of the ND distributions is 1.3 flashes per square kilometer per thunderstorm day in the central U.S. region, but only 0.2 flashes per square kilometer per thunderstorm day in Finland. The spatial distribution of the most intense 1% of the ND distributions illustrates that the most intense thunderstorm days occur in the central United States and upper Midwest, which differs from the maxima of the average annual flash density NA and the number of thunderstorm days TD, both of which occur in Florida and along the coast of the Gulf of Mexico. This method for using ND to quantify thunderstorm intensity is applicable to any region as long as the detection efficiency of the lightning-location network is high enough or known. This method can also be employed in operational forecasting to provide a quantitative measure of the lightning intensity of thunderstorms relative to climatology.

Spatio-temporal distribution of phytoplankton in the Danjiangkou Reservoir, a water source area for the Southto-North Water Diversion Project (Middle Route), China

One of the water source areas of the South-to-North Water Diversion Project is the Danjiangkou Reservoir (DJKR). To understand seasonal variation in phytoplankton composition, abundance and distribution in the DJKR area before water diversion, as well as to estimate potential risks of water quality after water diversion, we conducted an investigation on phytoplankton in the DJKR from August 2008 to May 2009. The investigation included 10 sampling sites, each with four depths of 0.5, 5, 10, and 20 m. In this study, 117 taxa belonging to 76 genera were identified, consisting of diatoms (39 taxa), green algae (47 taxa), blue-green algae (19 taxa), and others (12 taxa). Annual average phytoplankton abundance was 2.01 × 106 ind./L, and the highest value was 14.72 × 106 ind/L (at site 3 in August 2008). Phytoplankton abundance in front of the Danjiangkou Dam (DJKD) was higher than that of the Danjiang Reservoir Basin. Phytoplankton distribution showed a vertical declining trend from 0.5 m to 20 m at most sites in August 2008 (especially at sites of 1, 2, 4 and 10), but no distinct pattern in other sampling months. In December 2008 and March 2009, Stephanodiscus sp. was the most abundant species, amounting to 55.23% and 72.34%, respectively. We propose that high abundance of Stephanodiscus sp. may have contributed greatly to the frequent occurrence of Stephanodiscus sp. blooms in middle-low reaches of the Hanjiang River during the early spring of 2009. In comparison with previous studies conducted from 1992 to 2006, annual average phytoplankton density, green algae and blue-green algae species, as well as major nutrient concentrations increased, while phytoplankton diversity indices declined. This indicates a gradual decline in water quality. More research should be conducted and countermeasures taken to prevent further deterioration of water quality in the DJKR.

Rolled Winter Rye and Hairy Vetch Cover Crops Lower Weed Density but Reduce Vegetable Yields in No-tillage Organic Production

Winter annual cover crops, winter rye (Secale cereale L.) and hairy vetch (Vicia villosa Roth), can reduce weed density and build soil quality in organic production systems. There is interest in integrating cover crops and reduced tillage with organic vegetable production, but few studies have been conducted in regions with short growing seasons and cool soils such as the upper Midwest. We evaluated no-tillage production of tomato (Solanum lycopersicum L.), zucchini (Cucurbita pepo L.), and bell pepper (Capsicum annuum L.) planted into winter rye, hairy vetch, and a winter rye/hairy vetch (WR/HV) mixture that were mechanically suppressed with a roller–crimper at two locations in Minnesota. Average marketable yields of tomato, zucchini, and bell pepper in the rolled cover crops were reduced 89%, 77%, and 92% in 2008 and 65%, 41%, and 79% in 2009, respectively, compared with a no-cover control. Winter rye and the WR/HV mixture reduced average annual weed density at St. Paul by 96% for 8 to 10 weeks after rolling (WAR) and hairy vetch mulch reduced weeds 80% for 2 to 8 WAR, whereas at Lamberton, there was no consistent effect of cover treatments on weed populations. Winter rye and the WR/HV mixture had higher average residue biomass (5.3 and 5.7 Mg·ha−1, respectively) than hairy vetch (3.0 Mg·ha−1) throughout the season. Soil growing degree-days (SGDD) were lower in cover crop treatments compared with the no-cover control, which could have delayed early vegetable growth and contributed to reduced yields. All cover crop mulches were associated with low levels of soil nitrogen (N) (less than 10 mg·kg−1 N) in the upper 15 cm. Rolled winter annual cover crops show promise for controlling annual weeds in organic no-tillage systems, but additional research is needed on methods to increase vegetable crop yields in rolled cover crops.

An investigation of the relationship between sediment particles size and the development of green algal mats (Ulva prolifera) on the intertidal flats of Muan, Korea

The relationship between median grain size of sediments and the abundance in the wild of green algal mats (Ulva prolifera) on the intertidal flats of Muan, Korea, were investigated. The impact of substratum particle size on the growth and survival of germlings was examined in the laboratory. In the wild, the average annual density of algal mats was 7,950 ind m−2. The algal mats mainly occurred in sands and exhibited patchy distribution. Statistical analysis indicates significant spatial analysis differences and a significant relationship between density and the ratio of sands to silts, suggesting that the distribution and density of this species were related to particle size. In laboratory experiments, the survival rate of U. prolifera germlings was the lowest value (22%) on sediments with a median grain size of 63–125 μm. Laboratory experiments have generally shown a positive relationship between attachment or survival of the alga and substratum particles size. Our laboratory results indicate a clear link between germling settlement/survival and substratum particle size. These results explain the spatial differences in abundance observed in the field in relation to the distribution and ratio of sands to silt on the Muan flats.

Coleópteros acuáticos (C. H. Zimapán), Hidalgo, México. II. Coleoptera: Polyphaga y Myxophaga.

Se realizó un estudio faunístico de la comunidad de coleópteros acuáticos de los subórdenes Polyphaga y Myxophaga en el área de influencia de la Central Hidroeléctrica de Zimapán, Hidalgo, mediante muestreos mensuales en un ciclo anual (agosto-95 a julio-96) en cinco cuerpos de agua. De manera general, se describen y comparan entre sí la estructura de cada ensamblaje en términos de riqueza, composición, diversidad de Shannon, equitatividad de Pielou, rareza y densidad, adicionando datos de distribución de las especies dentro de la zona de estudio. Se hace una comparación faunística con otras áreas del país, y se proporciona una lista anotada y una clave ilustrada para las especies. Se recolectó un total de 8,787 adultos pertenecientes a 42 especies de 27 géneros y 10 familias. El Río San Francisco (RSF) presentó la mayor riqueza y diversidad, mientras que el Río Tula (RT) y arroyo El Saucillo (AES) registraron valores de diversidad y dominancia similares. AES exhibió la mayor densidad media anual, mientras que el Río San Juan (RSJ) y Río Tula (RT) presentaron una densidad media similar; AES obtuvo el mayor valor en rareza de especies. Se registran por primera vez para el estado de Hidalgo seis familias (Dryopidae, Limnichidae, Lutrochidae, Psephenidae, Heteroceridae y Microsporidae), 19 géneros (Helichus, Postelichus, Limnichoderus, Limnichites, Lutrochus, Psephenus, Dampfius, Microsporus, Laccobius, Berosus, Hemiosus, Hydrophilus, Chaetarthria, Anacaena, Helochares, Phaenonotum, Limnebius, Microcylloepus y Neoelmis) y 31 especies (Helichus suturalis, Postelichus musgravei, P. thoracicus, Limnichoderus lutrochinus, Limnichites nebulosus, Psephenus palpalis, P. oresbius, Lutrochus arizonichus, Dampfius mexicanus, Microcylloepus inaequalis, Neoelmis sp., Laccobius mexicanus, Berosus mexicanus, B. moerens, B. punctatissimus, Hemiosus exilis, Tropisternus lateralis nimbatus, Hydrophilus insularis, H. triangularis, Chaetarthria sp., Anacaena sp., Paracymus armatus, P. regularis, Enochrus carinatus fucatus, E. cristatus, E. pygmaeus pygmaeus, E. p. pectoralis, E. mexicanus, Helochares normatus, Limnebius sinuatus, Ochthebius angularidus).

Abundance Estimates of Skates (Rajidae) on the Continental Shelf of the Northeastern United States Using a Video Survey

AbstractFishing pressure is increasing on the seven skate species on the continental shelf of the northeastern United States. We provide the first abundance estimate for this skate complex by using data from an annual video survey (2003–2009) at depths of 40–120 m from Georges Bank through the Middle Atlantic Bight. Average annual skate densities were 0.014 individuals/m2 on Georges Bank and 0.009 individuals/m2 in the Middle Atlantic Bight; total skate abundance estimates averaged around 410 and 210 million fish, respectively. Coefficients of variation in density were low, averaging 9% for Georges Bank and 12% for the Middle Atlantic Bight. Abundance was relatively constant between 2003 and 2009 on Georges Bank and in the Middle Atlantic Bight except for a significant increase in 2006 within the latter area. These abundance estimates can be used for detailed population studies, analysis of harvest strategies, and community studies necessary for ecosystem‐based management.

Ambient air pollution correlates with hospitalizations for inflammatory bowel disease

Known genetic loci account for less than 25% of the risk for inflammatory bowel disease (IBD), suggesting a potential role for environmental triggers. The association between ambient air pollution and IBD hospitalizations has not been previously studied. Data from the Wisconsin Hospital Association (WHA) for the year 2002 was used to identify the number of IBD-related hospitalizations for each of the 72 counties in Wisconsin. Average annual emissions density (2002) for each of the six criteria pollutants were obtained for each county from the Environmental Protection Agency. Pearson correlation and Poisson regression analysis were performed at the level of the county. There was a mean of 81.3 IBD hospitalizations/100,000 population per county (range 0-174). The total criteria pollutant emissions density correlated significantly with adult IBD hospitalizations (Pearson's correlation coefficient (rho) 0.28, P = 0.02). On Poisson regression, a 1-log increase in the density of total criteria pollutant emission was associated with a 40% increase in the rate of IBD hospitalizations (incidence rate ratio [IRR] 1.40, 95% confidence interval [CI] 1.31-1.50) This was similar for both ulcerative colitis (UC) (IRR 1.48, 95% CI 1.27-1.73) and Crohn's disease (CD) hospitalizations (IRR 1.39, 95% CI 1.26-1.52). Analysis of each of the individual criteria pollutant emission densities revealed a significant association for all the component criteria pollutants. In this ecologic analysis, total air emissions of criteria pollutants appear to be associated with hospitalizations for IBD in adults. The ecologic design precludes drawing firm conclusions about association or causality and further research is needed.

Determination of several potential virulence factors in non-o1 Vibrio cholerae, Pseudomonas aeruginosa, faecal coliforms and streptococci isolated from Marrakesh groundwater

The dynamic, hemolytic and hemagglutination activities and the antibiotic resistance of non-O1 Vibrio cholerae, Pseudomonas aeruginosa, faecal coliforms (FC) and faecal streptococci (FS), isolated by standard membrane filtration methods from suburban and rural groundwater supplies, were carried out. Detectable non-O1 V. cholerae and P. aeruginosa was present in 81% and 88% of samples. The total occurrence of FC and FS during the period of study was 94%. The annual average densities of non-O1 V. cholerae were 4,903 MPN/100 mL. While, they were 206, 1,891 and 1,246 cfu/100 mL for P. aeruginosa, FC and FS respectively. Non-O1 V. cholerae strains had the highest percentage of hemolytic activities (alpha + beta) (71.29%), whereas 20.71% of FS, 16.88% of FC and 9.13% of P. aeruginosa strains produced hemolysin. Bacterial strains isolated were found to be adhesive, with percentages of 63.09%, 65.09%, 84.06% and 87.98% respectively for non-O1 V. cholerae, FS, FC and P. aeruginosa. As for antibiotic resistance, the overall resistance of non-O1 V. cholerae strains was 79%, whereas it was 100% for the other bacteria. Non-O1 V. cholerae resistance was expressed towards sulfamethoxazole (75%), streptomycin (62%) and cephalothin (60%). Obtained results indicated correlation between bacteriological pollution and their public health implications.

Dinámica poblacional del lobo (Canis lupus Linnaeus, 1758) en la zona este de la provincia de Castelló de la Plana durante los siglos XVI-XVII (1566-1624)

Our data suggest the decline of Wolf in the Mediterranean central municipalities in the Castelló de la Plana province (Spain) in the second half of the 16th century and the first quarter of the 17th century. Populations dynamics show: 1) a sex ratio average very favourable to males (4,1:1); 2) the hunting of females all the year round, of males in specific periods (January to June), and of pups from May to July; 3) an average of 4,6 pups in litter; and 4) an annual average density of 0,50 captures by 100 km2. This is a Wolf population subjected to pressure elements that have determined their negative conservation during the second half of the 16th century: 1) an obvious human demographic growth; 2) the breaking up of new grounds; 3) a food dicrease due to the extintion of deer and the decline in tranhumance ovin cattle; and 4) the presence of Wolf hunters.