Large-scale,millennial-length temperature reconstructions from tree-rings

Over the past two decades, the dendroclimate community has produced various annually resolved, warm season temperature reconstructions for the extratropical Northern Hemisphere. Here we compare these tree-ring based reconstructions back to 831 CE and present a set of basic metrics to provide guidance for non-specialists on their interpretation and use. We specifically draw attention to (i) the imbalance between (numerous) short and (few) long site chronologies incorporated into the hemispheric means, (ii) the beneficial effects of including maximum latewood density chronologies in the recently published reconstructions, (iii) a decrease in reconstruction covariance prior to 1400 CE, and (iv) the varying amplitudes and trends of reconstructed temperatures over the past 1100 years. Whereas the reconstructions agree on several important features, such as warmth during medieval times and cooler temperatures in the 17th and 19th centuries, they still exhibit substantial differences during 13th and 14th centuries. We caution users who might consider combining the reconstructions through simple averaging that all reconstructions share some of the same underlying tree-ring data, and provide four recommendations to guide future efforts to better understand past millennium temperature variability.     

Reproductive periodicity of the sparid,Acanthopagrus pacificus,on a hierarchy of temporal scales

The reproductive periodicity of the sparid, Acanthopagrus pacificus, over four temporal scales is described. Acanthopagrus pacificus had a short spawning season between June and September, and within this, a peak reproductive period from July to early September. During the peak period there were several spawning peaks corresponding to a lunar periodicity, with intense reproductive activity on new and full moons that peaked during the period of the full moon when the tidal range was greatest. At the smallest temporal scale, spawning occurred at night on ebb tides. Because this study draws on data collected in 1991 and 1995, it provides a useful baseline against which to judge future changes in reproductive periodicity.     

The incidence, distribution and expression of Australian grapevine yellows, restricted growth and late season leaf curl diseases in selected Australian vineyards

Surveys were conducted in four Chardonnay vineyards for 3 to 6 years and one Shiraz vineyard for 3 years to determine the yearly percentage of grapevines affected by Australian grapevine yellows disease (AGYd), restricted growth disease (RGd) and late season leaf curl disease (LSLCd). In each of the Chardonnay vineyards in each year, all three diseases were characterised by remission of disease in some grapevines, recurrence of disease in other grapevines and new observations of disease in previously unaffected grapevines. The pattern of temporal incidence of each disease was different between vineyards for the survey period. Although Koch's postulates have not been fulfilled, phytoplasmas are considered to be the most likely cause of AGYd. While some grapevines exhibited a combination of AGYd and RGd or AGYd and LSLCd, both RGd and LSLCd can occur independently of AGYd. Statistical analyses using log-linear models also indicated that RGd and LSLCd were not always associated with AGYd. Thus, it is possible that phytoplasmas are not the cause of RGd or LSLCd and their association is coincidental. Expression of AGYd in Shiraz grapevines occurred later in the season compared to Chardonnay. Very little recurrence of AGYd was observed in the Shiraz grapevines indicating that the variety Shiraz responds differently to phytoplasma infections, assuming that AGYd in Shiraz is a phytoplasma caused disease. RGd and LSLCd were not observed on any grapevines in the Shiraz vineyard.     

Pollination systems in a warm temperate evergreen broad-leaved forest on Yaku Island

Animal pollination in a warm temperate evergreen broad-leaved forest was observed on Yaku-shima Island, south of Kyushu, Japan. Three groups of plants were categorized: canopy-flowering tree species, understory-flowering tree species, and climber and epiphyte species. Each of these formed different pollination systems. The canopy-flowering tree species had shallow, dish-shaped flowers and utilized various types of opportunistic pollinators. Most of the climber and epiphyte species had deep, tube-shaped flowers and specialized pollinators, although some climber species which bloomed in the canopy especially in winter, had opportunistic pollinators. The understory-flowering tree species had large dish- or funnel-shaped flowers and endothermic pollinators able to tolerate the dark and cold conditions under the canopy. The individual trees of canopy-flowering tree species produced large numbers of flowers simultaneously (mass-flowering) and had a well synchronized flowering period. Each canopy-flowering tree species segregated its flowering time from those of the anothers. Climber and epiphyte species and most of the understory-flowering tree species produced small numbers of flowers sequentially (extended flowering) and showed a long flowering period.     

Effects of stream order and season on mineralization of [14C]-phenol in streams

Mineralization of trace levels of [¹⁴C]-phenol by heterotrophic microorganisms was quantified at 4 sites along a river continuum in southwestern Virginia. Significant phenol mineralization rates were detected in surface sediment and seston samples at all sites from August 1985 through May 1986. Phenol degradation was strongly affected by season (ANOVA; P < 0.0001). From a baseline rate in August (range: 1.19 × 10^-5 to 897 × 10^-4 mg phenol mineralized mg AFDW^-1 h^-1) phenol mineralization rose to a yearly maximum in October (range: 1.21 × 10^-4 to 1.16 × 10^-3 mg phenol mineralized mg AFDW^-1 h^-1) despite decreasing stream temperatures. This autumnal peak in phenol degradation was attributed to the pulsed input of allochthonous detritus, especially leaf litter, which contains substantial quantities of phenols and related compounds. Although phenol mineralization was significant in these streams, phenols were metabolized at much slower rates than more labile compounds present in the dissolved organic matter (DOM) pool. Estimates of turnover rates for three major components of DOM revealed that glucose and glutamate turnover rates (0.064–0.140 h^-1 mg sediment AFDW^-1 and 0.140–0.610 h^-1 mg sediment AFDW^-1, respectively) were, respectively, 2.2–4.7 × and 9.6–16.9 × greater than phenol turnover rates (0.015–0.064 h^-1 mg sediment AFDW^-1). Although the relatively low rates of utilization of refractory phenolic materials suggest that these compounds may accumulate and become more prevalent components of the DOM pool, phenol concentrations at the 4 study sites remained below detectable levels (i.e., < 1 g 1^-1) throughout the study. Consequently, it seems that although phenolic materials are metabolized more slowly than labile DOM, phenols are degraded at rates which preclude accumulation in the water column.     

Effects of fire season on flowering of forbs and shrubs in longleaf pine forests

Summary Effects of variation in fire season on flowering of forbs and shrubs were studied experimentally in two longleaf pine forest habitats in northern Florida, USA. Large, replicated plots were burned at different times of the year, and flowering on each plot was measured over the twelve months following fire. While fire season had little effect on the number of species flowering during the year following fire, fires during the growing season decreased average flowering duration per species and increased synchronization of peak flowering times within species relative to fires between growing seasons. Fires during the growing season also increased the dominance of fall flowering forbs and delayed peak fall flowering. Differences in flowering resulting from variation in fire season were related to seasonal changes in the morphology of clonal forbs, especially fall-flowering composites. Community level differences in flowering phenologies indicated that timing of fire relative to environmental cues that induced flowering was important in determining flowering synchrony among species within the ground cover of longleaf pine forests. Differences in fire season produced qualitatively similar effects on flowering phenologies in both habitats, indicating plant responses to variation in the timing of fires were not habitat specific.     

Artificial incubation of California condor Gymnogyps californianus eggs removed from the wild

The currrent California condor (Gymnogyps californianus) recovery plan entails increasing the reproductive rate via replacement-clutch manipulation of eggs. During the period from 1983 to 1985, 15 eggs were removed from wild nesting pairs for artificial incubation. The eggs were incubated at a dry bulb temperature of 36.4°C in modified forced-air Lyon Electric incubators. The incubation humidity was adjusted for individual eggs based on weight loss data (water = weight), 25.6–30.0°C wet bulb (41.0–63.0% Relative Humidity (RH)). The chicks were hatched initially under forced-air conditions of 36.1°C dry bulb, 31.1–01.7°C wet bulb (70.0–73.0% RH). In 1984, hatching parameters were changed to still-air conditions, 36.1°C dry bulb (top of the egg), 35.0°C dry bulb (bottom of the egg), 31.1–31.7°C wet bulb (70.0-73.0% RH). Tactile and auditory stimulation was utilized during the pip-to-hatch interval. From among 15 eggs collected, 13 hatched, and 12 condor chicks were raised successfully (hatchability: 86.7%; survivability: 92.3%).     

青年昼间发汗调定点正常值探讨

以加热腿足诱发前臂屈侧初始发汗的口腔温度阈值,作为发汗调定点的参考值(ToSSP),检测健康青年93人夏冬两季昼间ToSSP134次。结果表明,季节、性别、民族、于室温24℃左右变异达30％的相对湿度对ToSSP均无显著影响。提示ToSSP为一间接反映体温调定点较发汗率为稳定的指标。ToSSP的频数分布属于正态,均值为37.34℃,95％正常值范围为36.97～37.71℃。经于本工作前,后年份检测的两组结果以及与正常体温夜间最低时相组和发热患者组的ToSSP相验证,证明此正常值范围可靠。检测ToSSP的潜伏期夏季均值为19′57″冬季为18′22″(P<0.05)。检测ToSSP时口温变化分别与皮肤温、心率变化紧密相关,因而心率,皮肤温可作为监测ToSSP的辅佐指标。     

Variation in the oxytocin content of caprine corpora lutea across the breeding season

Ovarian tissues were obtained from cyclic goats during the early, mid and late breeding season. Immunoreactive oxytocin was measured by RIA in tissue extracts after chromatography on octadecylsilica cartridges. Luteal oxytocin concentrations were significantly greater during the early breeding season than during the mid or late breeding season. Oxytocin is luteolytic in goats. High concentrations of luteal oxytocin may be related to the high incidence of short estrus at the onset of the breeding season.