Where are Europe’s last primary forests?

Aim

Primary forests have high conservation value but are rare in Europe due to historic land use. Yet many primary forest patches remain unmapped, and it is unclear to what extent they are effectively protected. Our aim was to (1) compile the most comprehensive European‐scale map of currently known primary forests, (2) analyse the spatial determinants characterizing their location and (3) locate areas where so far unmapped primary forests likely occur.

Location

Europe.

Methods

We aggregated data from a literature review, online questionnaires and 32 datasets of primary forests. We used boosted regression trees to explore which biophysical, socio‐economic and forest‐related variables explain the current distribution of primary forests. Finally, we predicted and mapped the relative likelihood of primary forest occurrence at a 1‐km resolution across Europe.

Results

Data on primary forests were frequently incomplete or inconsistent among countries. Known primary forests covered 1.4 Mha in 32 countries (0.7% of Europe’s forest area). Most of these forests were protected (89%), but only 46% of them strictly. Primary forests mostly occurred in mountain and boreal areas and were unevenly distributed across countries, biogeographical regions and forest types. Unmapped primary forests likely occur in the least accessible and populated areas, where forests cover a greater share of land, but wood demand historically has been low.

Main conclusions

Despite their outstanding conservation value, primary forests are rare and their current distribution is the result of centuries of land use and forest management. The conservation outlook for primary forests is uncertain as many are not strictly protected and most are small and fragmented, making them prone to extinction debt and human disturbance. Predicting where unmapped primary forests likely occur could guide conservation efforts, especially in Eastern Europe where large areas of primary forest still exist but are being lost at an alarming pace.     

芒果老叶在增强UV-B辐射处理下的损伤和保护反应

以‘台衣一号’芒果盆栽苗离体老叶为试材,研究增强UV—B辐射条件下芒果老叶的损伤和保护反应。结果表明：UV—B辐射处理使芒果叶片MDA含量和相对电导率升高、叶绿素含量和叶绿素a／b降低,表明叶片受到损伤,且随处理时间延长叶片损伤加重。UV—B辐射处理叶片可溶性蛋白含量、抗氧化酶（SOD、CAT、POD）活性、保护色素（类胡萝卜素、类黄酮）和还原型GSH含量显著高于对照叶片,UV—B辐射处理叶片维生素C含量显著低于对照叶片,表明增强UV—B辐射可诱导叶片细胞通过提高活性氧清除能力和积累保护色素而直接吸收部分UV—B辐射来提高抗增强UV—B辐射损伤的能力。     

大型年长鱼类对海洋生态系统生物资源养护的作用

随着人口增长和渔业资源需求的上升,人类沿着食物网营养级自上向下捕捞渔业资源的趋势仍在持续,导致海洋生物多样性丧失及其生态功能与服务价值迅速下降。由捕捞活动造成的渔业诱导进化进一步导致鱼类资源小型化已受到国内外学者的广泛关注。从大型年长鱼类这一独特视角出发,综述了大型年长鱼类在种群繁衍过程中的作用,其具备巨大的繁殖能量输出、丰富的亲本繁殖经验以及强大的年龄组繁殖力贡献,更有利于种群的延续;大型年长鱼类对于初次性成熟亲鱼生殖洄游具有一定的引领作用,并在季节性集群繁殖过程中占据主导地位,可通过抑制小个体同类繁殖维护种群结构的稳定;大型年长鱼类在生态系统中更是占据了较高营养级和广阔的生态位宽度,面对生态环境的改变,具有更强的适应调控能力;大型年长鱼类在种群基因交流过程中亦起到十分关键的作用。保护大型年长鱼类更有利于鱼类种群的快速恢复,这为生物资源养护和渔业管理政策制定方面提供了一定的参考。     

Warming and drought reduce temperature sensitivity of nitrogen transformations

Shifts in nitrogen (N) mineralization and nitrification rates due to global changes can influence nutrient availability, which can affect terrestrial productivity and climate change feedbacks. While many single‐factor studies have examined the effects of environmental changes on N mineralization and nitrification, few have examined these effects in a multifactor context or recorded how these effects vary seasonally. In an old‐field ecosystem in Massachusetts, USA, we investigated the combined effects of four levels of warming (up to 4 °C) and three levels of precipitation (drought, ambient, and wet) on net N mineralization, net nitrification, and potential nitrification. We also examined the treatment effects on the temperature sensitivity of net N mineralization and net nitrification and on the ratio of C mineralization to net N mineralization. During winter, freeze–thaw events, snow depth, and soil freezing depth explained little of the variation in net nitrification and N mineralization rates among treatments. During two years of treatments, warming and altered precipitation rarely influenced the rates of N cycling, and there was no evidence of a seasonal pattern in the responses. In contrast, warming and drought dramatically decreased the apparent Q₁₀ of net N mineralization and net nitrification, and the warming‐induced decrease in apparent Q₁₀ was more pronounced in ambient and wet treatments than the drought treatment. The ratio of C mineralization to net N mineralization varied over time and was sensitive to the interactive effects of warming and altered precipitation. Although many studies have found that warming tends to accelerate N cycling, our results suggest that warming can have little to no effect on N cycling in some ecosystems. Thus, ecosystem models that assume that warming will consistently increase N mineralization rates and inputs of plant‐available N may overestimate the increase in terrestrial productivity and the magnitude of an important negative feedback to climate change.     

秦岭玉皇庙川金丝猴2-3岁内个体社会行为的性别差异

2005年3月至2006年5月在秦岭北坡的陕西周至国家级自然保护区玉皇庙地区,采用焦点动物取样法(Focal animal sampling)观察动物,利用瞬时记录法(Instantaneous recording)等记录数据,对2003年出生的7只秦岭川金丝猴(Rhinopithecus roxellana)个体(3♀、4♂)的社会理毛、社会玩耍、被驱赶、攻击、爬跨等行为进行了研究,以了解该物种社会行为的发育在2-3岁阶段是否存在性别间的差异。结果表明:雌、雄二性社会理毛行为的平均频次存在显著性差异(♀11.86%、♂6.55%),并且这种显著性差异也体现在理毛婴猴行为(♀3.64%、♂1.26%)和理毛母亲行为(♀4.61%、♂2.70%)方面;雄性社会玩耍行为的平均频次与雌性相比也有显著性差异(♀4.44%、♂7.39%),这与被驱赶行为性别差异的研究结果相同(♀0.42、♂1.98);爬跨行为的平均频次也表现出显著性的性别差异(♀0.034、♂1.83),如同攻击行为(♀0.043、♂0.088)。另外,我们在将2-3岁阶段分为4个小发育阶段的基础上,还发现除雌性理毛婴猴行为的发生频次和雄性被驱赶行为的发生频次与年龄(阶段)呈极显著正相关外,雌性和雄性其它行为的发生频次与年龄均不相关。因此,川金丝猴2-3岁内个体社会行为的发育具有显著性的性别差异,且在一定程度上反映了雌雄二性不同的生活史,而这种行为上的策略正是该物种在长期进化中在群体水平上对自然选择压力的回应,以增加个体的适合度,使种群得以繁衍.     

陕北撂荒地上优势蒿类叶片解剖结构及其生态适应性

对陕北丘陵区撂荒地上处于自然恢复演替不同时期的3种优势种蒿类铁杆蒿（Artemisia gmelinii Web．）、茭蒿（Artemisia giraldii Pamp．）、猪毛蒿（Artemisia scoparia）的叶片解剖结构进行了观察研究的结果表明,随着演替序列的发展,3种蒿类的栅栏组织随演替时间的推移呈现出全栅型-环栅型-过渡型的趋势,叶片解剖结构说明越靠近演替前期的蒿类对干旱的适应性越强。此外,3种蒿类的栅栏组织排列都很紧密,表皮细胞排列不规则,且具有表皮毛和腺毛等旱生适应结构;在猪毛蒿和茭蒿中还发现了特化的气腔结构。这些特征均能说明这些蒿类植物具有很好的抗旱适应性,作为环境改造的先锋物种,它们在当地的自然植被恢复演替中起着积极的正向推动作用。     

Abiotic and biotic responses to woody debris additions in restored old fields in a multi‐site Before‐After‐Control‐Impact experiment

Ecological restoration of former agricultural land can improve soil conditions, recover native vegetation, and provide fauna habitat. However, restoration benefits are often associated with time lags, as many attributes, such as leaf litter and coarse woody debris, need time to accumulate. Here, we experimentally tested whether adding mulch and logs to restoration sites in semi‐arid Western Australia can accelerate restoration benefits. All sites had been cropped and then planted with native trees and shrubs (i.e., Eucalyptus, Melaleuca, and Acacia spp.) 10 years prior to our experiment, to re‐establish the original temperate eucalypt woodland vegetation community. We used a Multi‐site Before‐After‐Control‐Impact (MBACI) design to test the effects on 30 abiotic and biotic response variables over a period of 2 years. Of the 30 response variables, a significant effect was found for just four variables: volumetric water content, decomposition, native herbaceous species cover and species richness of disturbance specialist ants. Mulch addition had a positive effect on soil moisture when compared to controls but suppressed growth of native (but not exotic) herbaceous plants. On plots with log additions, decomposition rates decreased, and species richness of disturbance specialist ants increased. However, we found no effect on total species richness and abundance of other ant species groups. The benefit of mulch to soil moisture was offset by its disbenefit to native herbs in our study. Given time, logs may also provide habitat for ant species that prefer concealed habitats. Indeed, benefits to other soil biophysical properties, vegetation, and ant fauna may require longer time frames to be detected. Further research is needed to determine whether the type, quantity, and context of mulch and log additions may improve their utility for old field restoration and whether effects on native herbs are correlated with idiosyncratic climatic conditions.     

Testing the weekend effect hypothesis: Time of day and lunar phase better predict the timing of births in laboratory‐housed primates than day of week

The weekend effect hypothesis proposes that captive primates are more likely to give birth during times of low disturbance and reduced staff activity. The hypothesis specifically predicts that laboratory‐housed primates will be more likely to give birth during the weekend than weekdays when staff activity is reduced. To date, support for the weekend effect hypothesis has been mixed and based on studies with relatively few subjects. To further examine the hypothesis, we analyzed the birthing patterns of three genera of laboratory‐housed primates: squirrel monkeys (Saimiri species, N = 2,090 births), owl monkeys (Aotus species, N = 479 births), and rhesus macaques (Macaca mulatta, N = 2,047 births). Contrary to predictions derived from the weekend effect hypothesis, the frequencies of births during weekends for all taxa were not significantly different from rates that would be expected by chance. However, while there was no variance across days of the week, all three taxa gave birth at nighttime, when staff was absent. This parallels reports of births in wild and captive monkeys, both diurnal and nocturnal, which are more likely to give birth during the night; plausibly a time when the environmental and social disturbance is lowest and the mother is safest to bond with her newborn infant. As all births occurred at night, we also explored the relationship between the lunar cycle and the timing of births timing. While the diurnal primates (i.e., Saimiri and Macaca) were no more likely to give birth on “bright” nights than “dark” nights, owl monkeys (Aotus) had a much higher frequency of births on bright nights than darker ones, and at rates that deviated from chance. Our data provide a more detailed understanding on how the environment may influence captive monkey births but do not support the oft‐cited weekend effect hypothesis.     

Microsatellite markers for northern red oak (Fagaceae: Quercus rubra)

We provide primer sequences for 14 (GA) _n microsatellite loci developed from northern red oak, an important timber species. We screened loci using two sets of samples. A parent–offspring set included DNA from seven acorns collected from one mother tree along with maternal DNA, to determine that all progeny carried a maternal allele at each locus. The other set was comprised of 10 adult trees sampled from Indiana old‐growth forest, providing a measure of diversity revealed by each locus.