Effects of environmental variables on surface temperature of breeding adult female northern elephant seals,Mirounga angustirostris,and pups

Pinnipeds spend extended periods of time on shore during breeding, and some temperate species retreat to the water if exposed to high ambient temperatures. However, female northern elephant seals (Mirounga angustirostris) with pups generally avoid the water, presumably to minimize risks to pups or male harassment. Little is known about how ambient temperature affects thermoregulation of well insulated females while on shore. We used a thermographic camera to measure surface temperature (T_s) of 100 adult female elephant seals and their pups during the breeding season at Point Reyes National Seashore, yielding 782 thermograms. Environmental variables were measured by an onsite weather station. Environmental variables, especially solar radiation and ambient temperature, were the main determinants of mean and maximum T_s of both females and pups. An average of 16% of the visible surface of both females and pups was used as thermal windows to facilitate heat loss and, for pups, this area increased with solar radiation. Thermal window area of females increased with mean T_s until approximately 26 °C and then declined. The T_s of both age classes were warmer than ambient temperature and had a large thermal gradient with the environment (female mean 11.2±0.2 °C; pup mean 14.2±0.2 °C). This large gradient suggests that circulatory adjustments to bypass blubber layers were sufficient to allow seals to dissipate heat under most environmental conditions. We observed the previously undescribed behavior of females and pups in the water and determined that solar radiation affected this behavior. This may have been possible due to the calm waters at the study site, which reduced the risk of neonates drowning. These results may predict important breeding habitat features for elephant seals as solar radiation and ambient temperatures change in response to changing climate.     

Domoic acid exposure and associated clinical signs and histopathology in Pacific harbor seals (Phoca vitulina richardii)

Domoic acid (DA) is a potent neurotoxin that has caused strandings and mortality of seabirds and marine mammals off the California coast. Pacific harbor seals (Phoca vitulina richardii) are an abundant, nearshore species in California; however, DA exposure and toxicosis have not been documented for harbor seals in this region. To investigate DA exposure in harbor seals, samples were collected from free-ranging and stranded seals off California to assess exposure, clinical signs of toxicosis, and brain lesions in harbor seals exposed to DA. Domoic acid was detected in 65% (17/26) of urine samples collected from apparently healthy free-ranging seals, with concentrations of 0.4–11.7 ng/ml. Domoic acid also was detected in feces (2.4–2887 ng/g), stomach contents (1.4 ng/g; stranded only), milk (2.2 ng/ml; stranded only), amniotic fluid (9.7 ng/ml; free-ranging only), fetal meconium (14.6–39.8 ng/g), and fetal urine (2.0–10.2 ng/ml). Clinical signs indicative of DA toxicosis were observed in two live-stranded seals, and included disorientation, seizures, and uncoordinated movements. Histopathology revealed the presence of brain lesions consistent with DA toxicosis in two live-stranded seals, and one free-ranging seal that died during capture. Results indicated that harbor seals were exposed to DA, exhibited clinical signs and histological lesions associated with DA exposure, and that pups were exposed to DA in utero and during lactation via milk. Future investigation is required to determine the magnitude of impact that DA has on the health and mortality of harbor seals.     

Comparison between hepatic and renal effects in rats treated with arsenic and/or antioxidants during gestation and lactation

The aim of this study was to determine whether biochemical changes occurred in the liver and kidney of arsenic (As) exposed pups during gestation and lactation, and investigate the potential beneficial role of antioxidants against arsenic exposure damage. Pregnant wistar rats received the following treatments as drinking water: (1) distilled water; (2) arsenic (50 mg/L); (3) antioxidants: zinc (20 mg/L) + vitamin C (2 g/L) + vitamin E (500 mg/L); (4) arsenic (50 mg/L) + antioxidants. As- intoxicated pups showed significant decreases in liver cholesterol and triglyceride concentration, whereas Aspartate aminotransferase (AST) and alkaline phosphatase (ALP) activities were increased. Treatment with antioxidants returns these values to control ones. TBARS production in both organs and liver glutathione peroxidase (GPx) activity also increased whereas catalase (CAT) activity in both organs decreased in arsenic-exposed pups; the antioxidant administration only recover TBARS concentration to control values. Our findings suggest that administration of antioxidants during gestation and lactation could prevent some of the negative effects of arsenic.     

Biomass and quality changes of forages along land use and soil type gradients in the riparian zone of Lake Naivasha,Kenya

The recession of the water level of Lake Naivasha has incrementally exposed land surfaces creating a chronosequential transect representing durations of 1–30 years of exposure to grazing. This chronosequence provides a unique model to study the effects of land use duration on resource availability and resource base quality. Particularly, pasture quality changes in the riparian land of tropical fresh water lakes have so far not been studied. We assessed the effect of the duration of exposure to grazing on the biomass production, crude protein content and energy quality of pastures in a 4 × 4 latin square design (4 chronosequence positions × 4 soil types). Species composition was recorded and biomass was sampled at monthly intervals from February to August 2011. Soil moisture was recorded using frequency domain reflectometry sensors. Vegetation samples were analyzed for dry matter, nitrogen and metabolizable energy. Increased land use duration favored a shift in species dominance from Pennisetum clandestinum to Cynodon plectostachyus, which was associated with a reduction in dry matter yield and increased plant nitrogen content. All measured variables tended to be higher in soils formed on alluvial than in those formed on lacustrine deposits. Increased soil N and gravimetric moisture content stimulated biomass accumulation. The crude protein yield and metabolizable energy changed with phenological stages of the pasture and declined significantly towards maturity (seed setting of grasses). Continuous grazing and reduced soil moisture content, both during low rainfall and increased distance from the lake shore, affected the composition of pasture grasses as well as forage yield and quality. This may thus differentially affect the suitability of the riparian land as pasture ground and feed resource area for grazing animals.     

Monitoring of aquatic macroinvertebrates as bioindicator for assessing the health of wetlands: A case study in the Central Himalayas,India

The present contribution encompasses the first case study on the aquatic macroinvertebrates as bioindicators for assessing the health of Asan wetland (area 3.2 km²), located in the foothills of Central Himalayas, India. Monthly sampling from all the sampling sites in five replicates was made for a period of 12 months (July 2002–June 2003) at 9:00–11:00 h. A total of 32 species of macroinvertebrates were found with the Ephemeroptera and Gastropoda being the most abundant component of invertebrates communities. The Shannon–Wiener diversity index calculated for macroinvertebrates ranged from 3.50 to 4.61. Seasonal fluctuations in the density of macroinvertebrates revealed maximum density (451–503 ind m^?2) during winter and minimum (126–143 ind m^?2) during monsoon season. The density of macroinvertebrates was influenced by the anthropogenic disturbances and water level fluctuations causing disturbance in the littoral zone of the wetland. The statistical relationships between turbidity, transparency, dissolved oxygen and water temperature and macroinvertebrates of Asan wetland were also computed for assessing the impact of anthropogenic disturbances on macroinvertebrates.     

Wolf denning behaviour in response to external disturbances and implications for pup survival

We conducted a 15-year study (1999–2014) of wolf denning behavior in Naliboki Forest, Belarus, to determine the extent to which some external factors (rain, mosquitoes, human disturbances) and litter size are negatively correlated with pup survival until autumn.For this purpose we entirely documented denning areas of 30 breeding wolf pairs. Initial denning area includes the natal den site and (ii) secondary den sites between which the parent wolves transported sucessively the litter during the rearing season.The number of den sites per denning area ranged from 1 to 4. The distances in kilometres differed significantly between den sites. The total number of dens (surface dens and burrows) was higher in the natal den site compared with the other den sites. The number of surface dens per den site was higher compared with burrows in den sites 1, 2 and 3 but not den site 4. A total of 168 pups was found over the 15 years. Litter sizes ranged from 1 to 11 (average 5.6 ± 1.9). The rate of pup survival ranged from 0 to 100% and averaged 54.5 ± 29%.We examined the bivariate association between environmental conditions (mosquitoes, rainfall and human presence) and number of surface dens, total number of burrows and number of den sites. Environmental conditions were assessed from spring to mid-summer. Results show that there was a positive relationship between environmental conditions and number of den sites, and also that more difficult environmental conditions (rainy weather, many mosquitoes) decreased pup survival both in absolute and in relative terms. A cluster analysis showed that pup survival was also influenced by human presence. Wolves probably have a more complicated denning behaviour following stressful event which may lead to less effectiveness for feeding or protecting pups. The number of pups surviving was also found to be lower when there were many (8–10) pups because den shifting is more risky in this case. Burrows improve pup survival. Our results tend to suggest that, in our study area, a high mortality rate of wolf pups could be related to external and internal factors of stress.     

Reaction of Harbor Seals to Cruise Ships

Abstract: The largest aggregations of harbor seals (Phoca vitulina) in Alaska, USA, haul out on floating ice in tidewater glacial fjords. Seals use these fjords in peak numbers during the critical periods of pupping, breeding, and molting when visits by tour ships also peak. Documented and suspected declines of harbor seals in fjords with rising vessel traffic underscore the need to better understand possible impacts, particularly in areas where ship visits have risen substantially in the past 2 decades. We examined the interruption of haul-out bouts of harbor seals due to approaching cruise ships in Disenchantment Bay, Alaska. We conducted observations from cruise ships and focused on disturbance of seals as evidenced by seals flushing into the water from the floating ice on which they rested. We investigated rate of flushing in relation to vessel distance, approach angle, group size, and seal type (mother, pup, or other). Using a survival-regression analysis, we found that the risk of disturbing harbor seals increased when ships approached within 500 m; seals approached as close as 100 m were 25 times more likely to enter the water than seals 500 m from a ship. Seals were 4 times more prone to enter the water when ships were approaching directly rather than passing abeam. Seals responded similarly regardless of group size or seal type. Energetic models indicated a potential to disrupt energy balance and cause thermal stress in disturbed pups if they spent >50% of their time in ice-chilled water. Studies at non-glacial sites suggest that pups spend 40–70% of their time in the water. Voluntary guidelines for approaching seals in Alaska recommend that cruise ships approach ≥91 m (100 yards), a distance at which we show 90% of seals would flush into the water. Our findings indicate a need to develop regulations to maintain a 500-m separation between cruise ships and seals in all Alaskan glacial fjords.     

Effects of reclamation of natural wetlands to a rice paddy on dissolved carbon dynamics in the Sanjiang Plain,Northeastern China

Natural wetlands play an important role in the global carbon cycle, and loss of dissolved carbon through water has been indicated as one of the most important carbon sources for riverine ecosystems. During the last century, a large natural wetland area was reported to be converted to other land use types such as rice paddy land around the world. In this study, we explored the dynamics of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) in two natural freshwater wetlands and a rice paddy field, which was reclaimed from the natural wetlands in the Sanjiang Plain, Northeastern China, during the growing season (May–October) of 2009. The DOC and DIC concentrations in the two ecosystems were significantly different (P < 0.05). The mean DOC concentrations during the growing season in the surface water of the Deyeuxia angustifolia and Carex lasiocarpa wetlands were 49.88 ± 5.44 and 27.97 ± 1.69 mg/L, respectively, while it was only 8.63 ± 2.54 mg/L in the rice paddy field. Specific ultra-violet light absorption at 254 nm (SUVA₂₅₄) of DOC increased by an average of 19.54% in the surface water from the natural wetlands to rice paddy, suggesting that DOC mobilized in the natural wetlands was more aromatic than that in the rice paddy field. The mean DIC concentration in surface water of the rice paddy was 5.25 and 5.04 times higher than that in the natural D. angustifolia and C. lasiocarpa wetlands, respectively. The average ratio of DIC to dissolved total carbon (DTC) for the water sampled from the artificial drainage ditch in the rice paddy field was 61.82%, while it was 14.75% from the nearby channel of natural wetlands. The significant differences in dissolved carbon concentration in surface water and channels originating from different land use types suggested that reclamation of natural wetlands to rice paddy field would reduce DOC runoff and increase the DIC concentration to adjacent watersheds. Our study results for the changed pattern in dissolved carbon after the natural wetland was transformed to paddy field could have important implications for studying the impacts of the large-scale land use change to carbon cycle and management.     

Surface electromyographic measurements on land prior to and after 90 min of submersion (swimming) are highly reliable

The purpose of this study was to investigate the reliability of surface electromyography (sEMG) measurements after submersion (swimming) for 90 min. Isometric maximal voluntary contractions (MVC) on land and in water were collected from eight muscles on the right side of the body in 12 healthy participants (6 women and 6 men). Repeated measures analyses of variance (general linear model ANOVA) showed no significant differences in the peak amplitude MVC scores between land pre and post measurements for all muscles, p > .05. The mean of the Intraclass correlation coefficient (1, 1) for land pre and land post was .985 with (95% Cl = .978–.990), for land pre and water pre .976 (95% Cl = .964–.984) and for land pre and post, water pre and post .981 (95% Cl = .974–.987). Measuring sEMG on land before and after a prolonged submersion is highly reliable without additional waterproofing when using electrodes with 57 mm diameter.     

Simulation of land use–soil interactive effects on water and sediment yields at watershed scale

Influences of vegetation management on soil erosion have been extensively studied. However, interactive effects between land use and soil are poorly documented in literature. Given the importance of understanding such effects for successful watershed management, the objective of this study was to examine the land use–soil interactive effects on water and sediment yields for the 117,845-ha drainage area upstream of the U.S. Geological Survey flow gauging station 08101000 in the Cowhouse Creek watershed located in north central Texas. The examination was implemented using the Soil and Water Assessment Tool (SWAT), a distributed watershed model that has been widely used to tackle problems relevant to nonpoint source pollution. A SWAT model was calibrated and validated in accordance with the observed daily streamflows at this gauging station. Subsequently, the calibrated model was used to examine changes of water and sediment yields as a result of the conversion of range brush to range grasses on an individual soil basis. The results indicated that for the study area, the removal of range brush would result in an annual water yield increase of 24 mm ha^?1 treated area. However, the removal on an upland soil with a moderately high permeability was predicted to increase the annual water yield by 80 mm ha^?1 treated area, while it would result in a small increase of annual sediment loading (4.2 t ha^?1 treated area) and a minimal alteration to the existing spatial patterns of sediment sources. The increase of water yield would be larger for the removal of range brush on a soil that is adjacent to the stream channels. For a given soil, the predicted water yield increase was greater for the wetter hydrologic condition than that for the drier one. A reasonable generalization of this study was that the development of best management practices for watershed health and sustainability may need to take into account land use–soil interactive effects on an individual soil basis.     

Relationship of fish and macroinvertebrate communities in the mid-Atlantic uplands: Implications for integrated assessments

Indices developed for stream bioassessment are typically based on either fish or macroinvertebrate assemblages. These indices consist of metrics which subsume attributes of various species into aggregate measures reflecting community-level ecological responses to disturbance. However, little is known about the relationship between fish and macroinvertebrate metrics, or about how ecological health assessments are affected by assemblage-specific responses to disturbance. We used principal component analysis (PCA) and regression analysis of existing fish (n = 371) and macroinvertebrate (n = 442) stream bioassessment data from a multi-source dataset to determine broad scale, within-assemblage metric patterns, and to examine the intercorrelation of fish and macroinvertebrate metrics (n = 246) and their response to watershed area and land use/land cover gradients. Fish and macroinvertebrate metrics expressed as principal components (PCs) accounted for 72.4 and 85.4% of dataset variance, respectively, with PC-metric patterns reflecting aspects of stream impairment including water and habitat quality. Model components predicting fish metric response differed among fish PCs, with watershed area and macroinvertebrate metric response strongly correlated with the first fish PC, and remaining fish PC models consisting of watershed area, land use, and macroinvertebrate PCs. Correlation between fish and macroinvertebrate PCs, and models relating fish and macroinvertebrate PCs generally explained less variation (13–27%) than metric response models of fish (25–34%) and macroinvertebrates (8–38%) to watershed area and land use/land cover variables. Best-response models integrating fish and macroinvertebrate PCs, watershed area, and land use/land cover variables accounted for the greatest variation in fish PCs (32–50%) across sites. Because fish and macroinvertebrate metrics provide different information on ecological condition, integrated use of information from multiple groups may be appropriate when developing monitoring programs.     

Performance of the Phytoplankton Index for Lakes (IPLAC): A multimetric phytoplankton index to assess the ecological status of water bodies in France

A new phytoplankton-based index was designed to respond to the Water Framework Directive (WFD) requirements concerning the assessment of lake ecological status. The “Indice Phytoplancton Lacustre” (IPLAC) is a multimetric index, taking into account biomass, abundance and species composition of communities. The first metric is based on the total phytoplankton biomass (MBA), the second on the abundance and taxonomic composition (MCS) of 165 indicator taxa. The IPLAC was developed on 2 independent databases, one for the calibration and the second for the validation of the metrics. The calibration dataset was composed of 255 “lake-years” from 214 distinct lakes sampled between 2005 and 2012. The validation dataset included 173 lake-years in order to confirm the response of the index to the trophic gradient and anthropogenic pressure.The results show that the IPLAC correctly highlights chemical pressure (eutrophication). Especially high Pearson correlations are shown with total phosphorus (r = −0.71, p-value <0.001), chlorophyll-a (r = −0.83, p-value <0.001) and water transparency (r = 0.73, p-value <0.001) which are the main proxies for the trophic level. Corine land cover was used as an indication of the anthropogenic pressure and good correlations are also found with the watershed land use, negatively correlated with agricultural area (r = −0.60, p-value <0.001), population density (r = −0.36, p-value <0.001) and positively with forest area (r = 0.57, p-value <0.001).The index is WFD-compliant and is dedicated to natural lakes and artificial water bodies in metropolitan France, and will be routinely used by the French Ministry of the Environment to assess lake ecological status through the phytoplankton community. However, the results must be carefully interpreted in two cases: reservoirs with large water level fluctuations, and samples that include less than 5 indicator species.     

Habitat selection by endangered Himalayan musk deer (Moschus chrysogaster) and impacts of livestock grazing in Nepal Himalaya: Implications for conservation

Habitat management within and outside protected areas is a key to effective conservation of wildlife. This is particularly vital for declining wildlife populations within the boundary of conservation areas, while sharing their potential habitat range with foraging livestock. In an effort to understand the habitat selection by Himalayan musk deer (Moschus chrysogaster) and explore any potential impacts of livestock grazing, we conducted the present study in a conservation area of central Nepal Himalaya. We recorded data on musk deer and livestock presence and absence (based on signs of fecal pellet, footprint, and resting site) along the elevational transect with associated topographic features (elevation, slope, aspect, distance to water, and vantage point distance) and vegetation features (tree spp., shrub spp., herb spp., and canopy-cover). Using logistic regression model we found that elevation, aspect, canopy-cover, and tree spp. in the area significantly affect the likelihood of habitat selection by musk deer. In particular, they selected the southern aspect of the area with elevation ≥ 3529 m, canopy-cover ≥ 42%, and with stands of Pinus spp. and Abies spp. Slope and canopy-cover significantly affected the foraging area selection by livestock. They selected the gentler slopes in the northern aspect of the area with altitude < 3529 m and canopy-cover < 42%. Also, presence of one group of herbivore (i.e. musk deer and livestock) was not found to affect the likelihood of habitat selection by the other group. These independent habitat selections are possibly the responses to morphological and behavioral adaptations than to impacts and interactions between these two groups of herbivores. We suggest to avoid any disturbances and livestock grazing on the area that disrupt the resources and conditions likely selected and occupied by musk deer population.     

Microbial quality of common carp and pikeperch fingerlings cultured in a pond fed with treated wastewater

A pond with a surface area of 0.94 ha and a maximum depth of 1.6 m, situated on land owned by a wastewater treatment plant in Olsztynek (Poland), was filled with water from underground springs in the pond bottom. Twice during the production season, the pond was fed with sewage which had been biologically treated in sequencing batch reactors (SBR). No commercial feed or medicinal products were applied to the pond and natural feed in the pond was the only source of nutrition for the fish. After the production season, pikeperch and carp fingerlings (aged 0+), weighed 8.4 ± 1.2 g fish^?1 and 62.1 ± 13.6 g fish^?1, respectively.The microbiological examinations included tests of the pond water and the contents of the digestive tract, skin mucus and the muscles of the fingerlings. In the water the total cell count, heterotrophic bacteria count at a temperature of 22 °C and 37 °C (HPC 22 °C and 37 °C), coliforms, fecal coliforms, Streptococcus faecalis, Salmonella sp. and Aeromonas hydrophila, were recorded. The same groups of bacteria were noted in the analyzed fish tissue without the total cell count. In addition, the antibiotic sensitivity of A. hydrophila, isolated from all the examined environments, was tested.The low count of all examined groups of bacteria in the pond water was noted. The common carp tissues were more contaminated than the pikeperch tissues, but the microbial quality of both species was satisfactory. A. hydrophila strains proved to be highly sensitive to the tested antibiotics. The results of this study indicate that a high microbiological quality in the fingerlings was achieved thanks to the seasonal feeding of pond water by treated sewage.     

Impact of landscape pattern at multiple spatial scales on water quality: A case study in a typical urbanised watershed in China

Buffer zones along rivers and streams can provide water quality services by filtering nutrients, sediment and other contaminants from the surface. Redundancy analysis was used to determine the influence of the landscape pattern at the entire catchment scale and at multiple buffer zone scales (100 m, 300 m, 500 m, 1000 m and 1500 m) on the water quality in a highly urbanised watershed. Change-point analysis was further applied to estimate the specific locations along a gradient of landscape metric that result in a sudden change in the water quality variable. The landscape characteristics for 100 m buffer zones appeared to have a slightly greater influence on the water quality than the entire catchment. The patch density of urban land and the large patch index of water were recognised as the dominant variables influencing the water quality for a 100 m buffer zone. The result of change-point analysis indicated key interval values of the two landscape metrics within the 100 m buffer zone. When the patch density of urban land was >30–40 n/100 ha and the largest patch index of water was >2.5–3.5%, the watershed water quality appeared to be better protected.     

Effects of lead exposure on the expression of amyloid β and phosphorylated tau proteins in the C57BL/6 mouse hippocampus at different life stages

The objective of this study was to investigate the effects of lead exposure on spatial learning and memory capacity and the expression of amyloid β and phosphorylated tau proteins in the mouse hippocampus. A total of 24 adult C57BL/6 mice (12 of each sex) were mated at a 1:1 ratio. After delivery, the litters were normalised to 6 pups per litter. During the lactation period, the pups were randomly separated into four groups: control, early exposure, late exposure, or long-term exposure. These groups were not exposed to lead, exposed to lead from birth to week 24, exposed to lead from week 24 to week 48, or exposed to lead from birth to 48 weeks of age, respectively. Lead exposure was induced by providing Pb-contaminated drinking water at a concentration of 0.1%. All of the pups were fed until 72 weeks of age, at which time their spatial learning and memory capacity was evaluated via the Morris water maze test. Then, the lead levels in their blood and hippocampus were measured via graphite furnace atomic absorption spectrometry. The protein expression of amyloid β and phosphorylated tau in the hippocampus was detected via Western blot. The results revealed that the hippocampal and blood lead levels were significantly higher in all of the groups exposed to lead than the control group (P < 0.05). The spatial learning and memory performances of the lead-exposed groups were much poorer than those of the control group (P < 0.05). The expression levels of amyloid β and phosphorylated tau proteins were increased in the lead-exposed groups compared to the control group (P < 0.05). The enhanced expressions of amyloid β and phosphorylated tau proteins might contribute to the impairment in spatial learning and memory in the lead-exposed mice.     

Oxidative stress programming in a rat model of postnatal early overnutrition — role of insulin resistance

Postnatal early overfeeding (EO) is related to later development of overweight and other metabolic disorders. As oxidative stress is implicated in most human diseases, as obesity and diabetes, we decided to study some parameters related to oxidative stress and insulin signaling in liver from EO animals in adult life. To induce EO, litter size was reduced to three pups per litter (SL: small litter) and groups with normal litter size (NL:10 pups per litter) were used as control. After weaning, rats had free access to standard diet and water. Body weight and food intake were monitored daily and offspring were killed at 180 days-old. Significant differences had P<.05 or less. As expected, SL rats had hyperphagia, higher body weight and higher visceral fat mass at weaning and adulthood. In liver, postnatal EO programmed for lower catalase (? 42%), superoxide dismutase (? 45%) and glutathione peroxidase (? 65%) activities. The evaluation of liver injury in adult SL group showed lower nitrite content (? 10%), higher liver and plasma malondialdehyde content (+ 25% and 1.1-fold increase, respectively). No changes of total protein bound carbonyl or Cu/Zn superoxide dismutase protein expression in liver were detected between the groups. Regarding insulin signaling pathway in liver, SL offspring showed lower IRβ (? 66%), IRS1 (? 50%), phospho-IRS1 (? 73%), PI3-K (? 30%) and Akt1 (? 58%). Indeed, morphological analysis showed that SL rats presented focal areas of inflammatory cell infiltrate and lipid drops in their cytoplasm characterizing a microsteatosis. Thus, we evidenced that postnatal EO can program the oxidative stress in liver, maybe contributing for impairment of the insulin signaling.     

Exploring spatio-temporal patterns of plankton diversity and community structure as correlates of water quality in a tropical stream

Ecology of plankton in the downstream reaches of Kaduna River, Zungeru, Niger state, Nigeria was investigated between April and August 2015. Plankton and surface water samples were collected monthly from three stations for analysis of plankton diversity and physico-chemical parameters respectively. Station 1 is relatively unperturbed station located at the outskirts of Zungeru town, station 2 with moderate human activity located in Zungeru town while station 3 with minimal level of anthropogenic activities was located in Wushishi town about 7 km from station 2. The result revealed that the minimum and maximum values for pH water temperature, air temperature, conductivity, dissolved oxygen (DO) biochemical oxygen demand (BOD), phosphate, Nitrate, and secchi disc transparency were 5.38–6.79, 25–31 °C, 26–31 °C, 32–72 μs/cm, 3.50–8.20 mg/l, 1.00–5.00 mg/l, 0.06–1.13 mg/l 0.44–1.31 mg/l, 39.140 cm respectively. A total of 26 species of zooplankton and 24 species of phytoplankton were encountered in the study. The highest number of plankton (20 taxa) was recorded at station 2 while station 1 with 18 taxa and station 3 with 13 representative taxa. For zooplankton, the highest number of taxa was recorded at station 1 (20 taxa), followed by station 3 (14 taxa) and 10 taxa in station 2 were identified. Copepoda of the order cyclopidae dominated all the three stations while Bacillariophyta dominated the three stations for phytoplankton diversity. Canonical correspondence analysis (CCA) ordination was used to determine phytoplankton and zooplankton abundance in relation to the physico-chemical parameters. Nitrate, phosphate and dissolved oxygen had over riding influence on the distribution of the plankton in the water body which indicate that the river is still very productive in terms of providing starter food organisms for higher aquatic life. However, care should be taken to protect the river from further deterioration due to various degrees of human activities.     

Shifts in thermoregulatory strategy during ontogeny in harp seals (Pagophilus groenlandicus)

Heat balance can be difficult for young and/or small animals in polar regions because environmental conditions in combination with small body size or physiological immaturity can increase heat loss. We investigated how thermoregulatory patterns change with ontogeny in 5 age classes of harp seal (Pagophilus groenlandicus) from birth to post-molt to further understand the timing of thermoregulatory development in relation to their potential vulnerability to ongoing fluctuations in the extent and stability of Arctic pack ice. We measured changes in the amount, conductivity, and resistance of the seal pups׳ insulative layers (blubber and fur), the potential for endogenous heat-generation by shivering (muscle enzyme activity), and nonshivering thermogenesis (NST; brown adipose tissue (BAT) uncoupling protein 1 (UCP1) expression and mitochondrial density). There was no significant difference in blubber conductivity among age classes, though the amount of blubber insulation significantly increased from birth to weaning. Pelage conductivity was low (0.12±0.01 W m⁻¹ °C⁻¹) except in 9-day old pups (0.40±0.08 W m⁻¹ °C⁻¹); the significantly higher conductivity may signal the beginning of the molt, and this age group may be the most vulnerable to early water entry. Citrate synthase activity significantly increased (49.68±3.26 to 75.08±3.52 μmol min⁻¹ g wet weight⁻¹) in the muscle; however it is unlikely that increasing a single enzyme greatly impacts heat generation. BAT of younger pups contained UCP1, though expression and mitochondrial density quickly declined, and the ability of pups to produce heat via NST was lost by weaning. While total thermal resistance did not differ, neonatal and early nursing animals gained the majority of their thermal resistance from lanugo (82.5±0.03%); however, lanugo is not insulative when wet, and NST may be important to maintain euthermia and dry the coat if early immersion in water occurs. By late nursing, blubber seems sufficient as insulation (75.87±0.01% of resistance after 4 weeks), but high conductivity of fur may be responsible for retention of UCP1 expression. Weaned animals rely on blubber insulation, and no longer need NST, as wetted fur is no longer a threat to euthermia.     

Determination of priority nature conservation areas and human disturbances in the Yangtze River Basin,China

Because of limitation of manpower, funding, and land available in conservation, the problem of how to select essential regions to establish protection systems for biodiversity maintenance has been widely discussed. In an effort to address the problem, this study has aimed to select a set of priority areas and to determine their priority order by quantifying human disturbances for each area in the Yangtze River Basin (YRB). This basin covers 2.143 million km², or more than 20% of China's territory. The habitats of 627 indicator species were predicted as a proxy for biodiversity. A conservation planning tool, MARXAN, was used to determine the optimal set of planning units, and three different target scenarios were generated. In addition, under the assumption that if two areas have equal value for conservation, the one suffering more severe disturbance needs more urgent protection than the other, priority ranking analysis was carried out using a 6-12-1 BP artificial neural network. Then hierarchical cluster analysis was applied to the classifications of human disturbances to formulate more detailed conservation strategies. By integrating the degree of irreplaceability of each unit, expert experience, and mountain boundaries, 17 biodiversity priority areas containing 33,200 units over an area of 0.83 million km² were defined. These areas also protected 56% of 32 types of rare forest ecosystem and 76.4% of six types of rare grassland ecosystem on average. According to the evaluation of human impact, a priority order and five types of human disturbance areas were generated. Some protection gaps were also identified, such as the northern part of the Wuyi Mountains. Moreover, the determination of priority nature conservation areas on a large scale can be used to influence the building of a well-connected protection network in each individual area, so that effective genetic communication can occur between species or groups of species. Conservation decisions focusing on the dominant impact factors that are threatening biodiversity sustainability are required as well.