Biodiversity Differences between Managed and Unmanaged Forests: Meta-Analysis of Species Richness in Europe

Abstract: Past and present pressures on forest resources have led to a drastic decrease in the surface area of unmanaged forests in Europe. Changes in forest structure, composition, and dynamics inevitably lead to changes in the biodiversity of forest‐dwelling species. The possible biodiversity gains and losses due to forest management (i.e., anthropogenic pressures related to direct forest resource use), however, have never been assessed at a pan‐European scale. We used meta‐analysis to review 49 published papers containing 120 individual comparisons of species richness between unmanaged and managed forests throughout Europe. We explored the response of different taxonomic groups and the variability of their response with respect to time since abandonment and intensity of forest management. Species richness was slightly higher in unmanaged than in managed forests. Species dependent on forest cover continuity, deadwood, and large trees (bryophytes, lichens, fungi, saproxylic beetles) and carabids were negatively affected by forest management. In contrast, vascular plant species were favored. The response for birds was heterogeneous and probably depended more on factors such as landscape patterns. The global difference in species richness between unmanaged and managed forests increased with time since abandonment and indicated a gradual recovery of biodiversity. Clearcut forests in which the composition of tree species changed had the strongest effect on species richness, but the effects of different types of management on taxa could not be assessed in a robust way because of low numbers of replications in the management‐intensity classes. Our results show that some taxa are more affected by forestry than others, but there is a need for research into poorly studied species groups in Europe and in particular locations. Our meta‐analysis supports the need for a coordinated European research network to study and monitor the biodiversity of different taxa in managed and unmanaged forests.     

Lactation,maternal behavior and infant growth in common marmoset monkeys (<Emphasis Type="Italic">Callithrix jacchus</Emphasis>): effects of maternal size and litter size

We examined the relationship between lactation performance and infant growth in a captive population of common marmosets (Callithrix jacchus) that varied in both maternal and litter size. Though common marmosets display a typical primate pattern of dilute milk and relatively slow infant growth rates (factors associated with low daily lactation investment and minimal maternal size effects), we hypothesized that the marmoset's small body size would make lactation investment more sensitive to maternal size than is true for larger-bodied primates. Smaller mothers rearing twins had lower milk fat, lower gross energy in milk samples collected in mid to late lactation and lower nursing-bout frequencies than did large mothers nursing twins. Lactation performance and maternal behavior did not differ between large and small mothers when rearing singletons, with a single exception: small mothers had a lower gross energy in mid-lactation milk samples. Relative growth rates in twins but not singletons were affected by maternal size, such that small mothers supported more growth per infant when rearing singletons while large mothers supported more growth per infant when rearing twins. Among the larger mothers, only, older mothers supported somewhat, though not significantly, less growth per infant, regardless of litter size. Twin infants of small mothers appeared to respond to below-optimal levels of milk yield by initiating maternal carrying less often. The relative energy intake of mothers was similar regardless of litter or maternal size. Small mothers rearing twins drew more heavily on reserves, reflected in a linear weight loss during lactation; however, the reserves drawn upon were inadequate to meet the lactation demand, resulting in lower milk energy output. In addition, small mothers rearing twins were more likely to be ill and less likely to be fertile in the year following lactation than were large mothers of twins or mothers of any size rearing singletons.     

The Evolution and Role of Non-OPEC Production in the International Oil Market

In 1982, for the first time since OPEC was founded in 1961, its production was surpassed by the non-OPEC countries in the world excluding the centrally planned economies. In that year, for the world as a whole, OPEC provided 35% of the oil consumed. The decline was brought about by a decrease in consumption and by a marked increase in production from non-OPEC sources. It is expected that non-OPEC producers will have the capacity to meet more than half of the world's oil requirements until the early 1990s, at which time OPEC producers will again assume the role of providing over 50% of the world's oil.     

Heterologous expression of <Emphasis Type="Italic">LamA</Emphasis> gene encoded endo-β-1,3-glucanase and CO<Subscript>2</Subscript> fixation by bioengineered <Emphasis Type="Italic">Synechococcus</Emphasis> sp. PCC 7002

The gene for the catalytic domain of thermostable endo-β-1,3-glucanase (laminarinase) LamA was cloned from Thermotoga maritima MSB8 and heterologously expressed in a bioengineered Synechococcus sp. PCC 7002. The mutant strain was cultured in a photobioreactor to assess biomass yield, recombinant laminarinase activity, and CO₂ uptake. The maximum enzyme activity was observed at a pH of 8.0 and a temperature of 70°C. At a CO₂ concentration of 5%, we obtained a maximum specific growth rate of 0.083 h^–1, a biomass productivity of 0.42 g?L^–1?d^–1, a biomass concentration of 3.697 g?L^–1, and a specific enzyme activity of the mutant strain of 4.325 U?mg^–1 dry mass. All parameters decreased as CO₂ concentration increased from 5% to 10% and further to 15% CO₂, except enzyme activity, which increased from 5% to 10% CO₂. However, the mutant culture still grew at 15% CO₂ concentration, as reflected by the biomass productivity (0.26 g?L^–1?d^–1), biomass concentration (2.416 g?L^–1), and specific enzyme activity (3.247 U?mg^–1 dry mass).

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Household youth on minority operated farms in the United States, 2000: exposures to and injuries from work, horses, ATVs and tractors

INTRODUCTION: It is likely that youth living on minority operated farms (<3% of U.S. farms) face hazards similar to the general farm population; however, since minority youth are not well represented by general farm surveys, this information hasn't been confirmed. METHOD: Nonfatal injury and exposure data were obtained from the 2000 Minority Farm Operator Childhood Agricultural Injury Survey (M-CAIS). RESULTS: On racial minority farms, there were an estimated 28,600 household youth. Of these, about 41% worked, 26% rode a horse, 23% drove an ATV, and 23% operated a tractor. On Hispanic farms, there were an estimated 17,998 household youth. Of these, 44% worked, 30% rode a horse, 27% drove an ATV, and 25% operated a tractor. CONCLUSIONS: These results show the value of conducting a survey of minorities to identify high risk groups and target issues that may be unique to the minority farm population.     

渤海湾两条河流及其近岸海域水体中DOM的光谱特征及影响因素

应用三维荧光光谱结合吸收光谱分析,研究了2019年夏季天津市大清河-独流减河水系和河北省黄骅市捷地减河及其河口区水体中溶解有机物（DOM）的空间分布特征、来源及其影响因素。紫外-可见光谱结果表明,研究区水体的SUVA₂₅₄与盐度有显著正相关关系;两条河流的下游水体中S_275-295均值均大于上游和中游。平行因子分析结果表明,两条河流均检测到两种类腐殖质组分C1（240,300/390 nm）和C3（260,335/477 nm）以及一种类蛋白质组分C2（225,275/339 nm）。在大清河-独流减河水系及其近岸海域水体中,这三种组分与盐度呈显著负相关关系,其中由于人为输入（TN和TP含量高,工业排污）影响导致C2与盐度的相关性弱于C1和C3。该水系水体在低盐度时C2的占比高于捷地减河,主要受到工农业废水输入与其支流子牙河汇入的共同影响,而捷地减河主要受农业废污水输入的影响。此外,自然因素（盐度、海水混合）和人为因素（人为输入、筑坝拦截）的不同导致渤海湾两条入海河流中有色溶解有机质（CDOM）的光学特性和混合行为出现显著差异。其中筑坝拦截导致独流减河坝前水体的CDOM平均分子量低于下游水体,并且增强了河口区陆源类腐殖质的去除作用。综上,三维荧光光谱结合平行因子分析能判别河流局部条件的差异对整体CDOM空间分布特征的影响,研究结果可为渤海湾地区河流及河口水体CDOM生物地球化学过程研究提供基础数据。     

基于游客视角的红色旅游资源开发价值共创机制

以井冈山风景名胜区作为案例地,基于价值共创理论,运用大数据分析与内容分析方法,收集并分析马蜂窝网站上井冈山景区的游记文本,构建红色旅游资源开发的价值共创机制:以历史文化遗产、自然景观资源和标志性景观符号为资源基础,游客通过红色文化体验、学习培训活动、解说服务体验和自然景观体验等实践活动,获得对红色历史文化的认知、情感的联结和价值观的塑造。另外,红色旅游景区现有的价值共创实践仍旧有限,红色旅游资源开发价值共创机制整合了游客需求、景区支持以及可能存在的价值共创实践,对创新红色旅游资源开发利用手段与产业转型升级具有实践意义。     

Interspecific resource partitioning in sympatric ursids.

The fundamental niche of a species is rarely if ever realized because the presence of other species restricts it to a narrower range of ecological conditions. The effects of this narrower range of conditions define how resources are partitioned. Resource partitioning has been inferred but not demonstrated previously for sympatric ursids. We estimated assimilated diet in relation to body condition (body fat and lean and total body mass) and reproduction for sympatric brown bears (Ursus arctos) and American black bears (U. americanus) in south-central Alaska, 1998-2000. Based on isotopic analysis of blood and keratin in claws, salmon (Oncorhynchus spp.) predominated in brown bear diets (> 53% annually) whereas black bears assimilated 0-25% salmon annually. Black bears did not exploit salmon during a year with below average spawning numbers, probably because brown bears deterred black bear access to salmon. Proportion of salmon in assimilated diet was consistent across years for brown bears and represented the major portion of their diet. Body size of brown bears in the study area approached mean body size of several coastal brown bear populations, demonstrating the importance of salmon availability to body condition. Black bears occurred at a comparable density (mass:mass), but body condition varied and was related directly to the amount of salmon assimilated in their diet. Both species gained most lean body mass during spring and all body fat during summer when salmon were present. Improved body condition (i.e., increased percentage body fat) from salmon consumption reduced catabolism of lean body mass during hibernation, resulting in better body condition the following spring. Further, black bear reproduction was directly related to body condition; reproductive rates were reduced when body condition was lower. High body fat content across years for brown bears was reflected in consistently high reproductive levels. We suggest that the fundamental niche of black bears was constrained by brown bears through partitioning of food resources, which varied among years. Reduced exploitation of salmon caused black bears to rely more extensively on less reliable or nutritious food sources (e.g., moose [Alces alces], berries) resulting in lowered body condition and subsequent reproduction.     

Estimating the Density of Honeybee Colonies across Their Natural Range to Fill the Gap in Pollinator Decline Censuses

Abstract: Although pollinator declines are a global biodiversity threat, the demography of the western honeybee (Apis mellifera) has not been considered by conservationists because it is biased by the activity of beekeepers. To fill this gap in pollinator decline censuses and to provide a broad picture of the current status of honeybees across their natural range, we used microsatellite genetic markers to estimate colony densities and genetic diversity at different locations in Europe, Africa, and central Asia that had different patterns of land use. Genetic diversity and colony densities were highest in South Africa and lowest in Northern Europe and were correlated with mean annual temperature. Confounding factors not related to climate, however, are also likely to influence genetic diversity and colony densities in honeybee populations. Land use showed a significantly negative influence over genetic diversity and the density of honeybee colonies over all sampling locations. In Europe honeybees sampled in nature reserves had genetic diversity and colony densities similar to those sampled in agricultural landscapes, which suggests that the former are not wild but may have come from managed hives. Other results also support this idea: putative wild bees were rare in our European samples, and the mean estimated density of honeybee colonies on the continent closely resembled the reported mean number of managed hives. Current densities of European honeybee populations are in the same range as those found in the adverse climatic conditions of the Kalahari and Saharan deserts, which suggests that beekeeping activities do not compensate for the loss of wild colonies. Our findings highlight the importance of reconsidering the conservation status of honeybees in Europe and of regarding beekeeping not only as a profitable business for producing honey, but also as an essential component of biodiversity conservation.