Ten polymorphic microsatellite loci for the endangered Buena Vista Lake shrew (Sorex ornatus relictus)

The ornate shrew (Sorex ornatus) is restricted to the vanishing wetlands of California, USA and Baja California, Mexico. Several subspecies of ornate shrews are considered ‘mammal species of special concern’ in California by the Department of Fish and Game, and one (Sorex ornatus relictus) has recently been listed as endangered. Populations of shrews around Buena Vista Lake have been diminished or extirpated due to habitat deterioration and human development. In order to study the patterns of genetic variation in isolated populations of Buena Vista Lake shrews, we developed 10 polymorphic microsatellite loci. There were 6–27 alleles per locus, and the loci had heterozygosity values that ranged from 20 to 80%. In addition, we screened 20 different populations of S. ornatus, eight species within two subfamilies of shrews (Soricinae and Crocidurinae), as well as in a mole (Talpidae, Neurotrichus gibbsii), to determine if these loci could be informative in other species as well.     

Activity following arousal in winter in North American vespertilionid bats

• 1 Many bat species hibernate to conserve energy during winter and like all hibernators they commonly arouse. During these arousals, some bats may undertake activities away from the hibernation site. Systematic ecological studies of the frequency and purpose of winter activity in temperate zone bats of North America are rare and much of the literature involves observations of single individuals or unmarked populations.
• 2 We review the available literature on winter activity among North American vespertilionid bats to highlight the paucity of data on this subject and to stimulate future research. Due to the lack of repeated, systematic studies on most North American species, the conclusions drawn are general or pertain only to parts of the geographical range of any species.
• 3 We suggest that winter activity is ubiquitous among temperate zone bats, but the degree and purpose of activity varies greatly between and within species. In general, cave‐dwelling bats tend to be relatively inactive compared with tree and foliage roosting bats during winter.
• 4 Cave‐dwelling and tree cavity‐dwelling species do not appear to feed, but they do drink and occasionally copulate during the hibernation period. Species that hibernate in foliage or leaf litter are the most active species during winter and may feed and drink throughout winter, although they probably do not copulate because of their solitary nature.
• 5 We encourage researchers to conduct studies on all aspects of winter activity for North American vespertilionids across wide latitudinal and altitudinal gradients. We suggest studies in the near future be focused on estimating the energetic costs and benefits of winter activity through determination of the frequency and intensity of winter feeding activity and more thorough examinations of movements within and among caves. Studies on common, wide‐ranging species have the potential to illuminate large‐scale patterns and differences and should be favoured over studies on rarer species.

     

伊比利亚河共生的当年生鳟和埃布罗河鲒的夏季摄食关系

1996—1998年8月在Larraun河（埃布罗河流域,西班牙北部）共捕获306尾埃布罗河鱥和185尾0龄的鳟,分析比较了胃含物组成,并测定了种间的食物重叠。食物的个数百分比组成表明两种都主要摄食水生无脊椎动物。摄食策略图显示两种都是摄食不同食物种类的广食性种类。另外,比较胃含物和底栖大型无脊椎动物群落表明,0龄的鳟和埃布罗河鱥不摄食光螺科、钩虾科、细蜉科、四节蜉科和卷稹科的物种,而喜食摇蚊科、五节蜉科和毛翅目物种。尽管简化的Monsita’s指数表明Larraun河中这两种鱼之间的食物重叠是显著的,但由于栖息地不同和摄食的可塑性可以降低种间的竞争,使得该水域的这两种鱼能以相对较大的数量共存。然而,在食物资源和可用栖息地有限的河域,埃布罗河鱥的引入,其适应性和可塑性有可能威胁单独存在的鳟     

伊比利亚河共生的当年生鳟和埃布罗河鳟的夏季摄食关系

1996-1998年8月在Larraun河(埃布罗河流域,西班牙北部)共捕获306尾埃布罗河(鱼岁)和185尾0龄的鳟,分析比较了胃含物组成,并测定了种间的食物重叠.食物的个数百分比组成表明两种都主要摄食水生无脊椎动物.摄食策略图显示两种都是摄食不同食物 种类的广食性种类.另外,比较胃含物和底栖大型无脊椎动物群落表明,0龄的鳟和埃布罗河(鱼岁)不摄食光螺科、钩虾科、细蜉科、 四节蜉科和卷襀科的物种,而喜食摇蚊科、五节蜉科和毛翅目物种.尽管简化的Morisitas指数表明Larraun河中这两种鱼之间的食物重叠是显著的,但由于栖息地不同和摄食的可塑性可以降低种间的竞争,使得该水域的这两种鱼能以相对较大的数量共存.然而,在食物资源和可用栖息地有限的河域,埃布罗河(鱼岁)的引入,其适应性和可塑性有可能威胁单独存在的鳟     

A simple calibrated model of Amazon rainforest productivity based on leaf biochemical properties

A simple ‘big leaf’ ecosystem gas exchange model was developed, using eddy covariance data collected at an undisturbed tropical rainforest in south-western Amazonia (Brazil). The model used mechanistic equations of canopy biochemistry combined with an empirical stomatal model describing responses to light, temperature and humidity. After calibration, the model was driven using hourly data from a weather station at the top of the tower at the measurement site, yielding an estimate of gross primary productivity (annual photosynthesis) in 1992/1993 of about 200 mol C m^?2 year ^?. Although incoming photon flux density emerged as the major control on photosynthesis in this forest, at a given PAR CO₂ assimilation rates were higher in the mornings than in the afternoons. This was attributable to stomatal closure in the afternoon in response to increasing canopy-to-air vapour pressure differences. Although most morning gas exchange was clearly limited by the rate of electron transport, afternoon gas exchange was generally observed to be very nearly co-limited by both Rubisco activity (V_max) and electron transport rate. The sensitivity of the model to changes in nitrogen allocation showed that the modelled ratio of V_max to electron transport (J_max) served nearly to maximize the annual carbon gain, and indeed, would have resulted in almost maximum annual carbon gain at the pre-industrial revolution atmospheric CO₂ concentration of 27 Pa. Modelled gross primary productivity (GPP) was somewhat lower at 27 Pa, being about 160 mol C m^?2 year^?1. The model suggests that, in the absence of any negative feedbacks on GPP, future higher concentrations of atmospheric CO₂ will continue to increase the GPP of this rainforest, up to about 230 mol C m^?2 year^?1 at 70 Pa.     

The use of eddy covariance to infer the net carbon dioxide uptake of Brazilian rain forest

• 1 Eddy covariance measurements of CO₂ flux, based on four and six week campaigns in Rondôdnia, Brazil, have been used in conjunction with a model to scale up data to a whole year, and thus estimate the carbon balance of the tropical forest ecosystem, and the changes in carbon balance expected from small interannual variations in climatological conditions.
• 2 One possible source of error in this estimation arises from the difficulty in measuring fluxes under stably stratified meteorological conditions, such as occur frequently at night. Flux may be ‘lost’ because of low velocity advection, caused by nocturnal radiative cooling at sites on raised ground. Such effects may be detected by plotting the net ecosystem flux of CO₂, F_eco is a function of wind speed. If flux is ‘lost’ then F_eco is expected to decline with wind speed. In the present data set, this did not occur, and F_eco was similar to the nocturnal flux estimated independently from chamber measurements.
• 3 The model suggests that in 1992/3, the Gross Primary Productivity (GPP) was 203.3 mol C m^?2 y^?1 and ecosystem respiration was 194.8 mol C m^?2 y^?1, giving an ecosystem carbon balance of 8.5 mol C m^?2 y^?1, equivalent to a sink of 1.0 ton C ha^?1 y^?1. However, the sign and magnitude of this figure is very sensitive to temperature, because of the strong influence of temperature on respiration.
• 4 The model also suggests that the effect of temperature on the net carbon balance is strongly dependent on the partial pressure of CO₂.