Expert assessment of landscape-level conservation strategies in boreal forests for biodiversity,recreation and water quality

Determining effects of landscape-level conservation strategies is needed, yet a challenging and costly endeavour. The aim of this study was to evaluate the effects of landscape-level conservation strategies in forests on biodiversity and provision of two ecosystem services (recreation and water quality). Specifically, we focused on the spatial allocation of unmanaged areas in production forests and different levels of “land sharing” or “land sparing”. They were represented through seven scenarios constructed for a boreal managed forest landscape in central Sweden. All scenarios had the same total level of conservation effort, but they differed in the combinations of sizes of unmanaged areas and how these areas were spread in the landscape. In one scenario, this was complemented with extended rotation of production areas. Experts (researchers in relevant fields) assessed these scenarios for overall biodiversity, recreation, and water quality. We used the Delphi technique: experts filled out an online survey individually in two rounds. In the second round they were familiarized with anonymized responses of others from the previous round. There was little agreement between experts whether concentration of unmanaged areas in one part of the landscape or dispersion of them around the entire area is more beneficial, for biodiversity as well as for the two ecosystem services. The explanation of the opinions given by biodiversity experts were based on different ecological theories resulting in different conclusions (mainly habitat complementation vs. metapopulation ecology). A few large unmanaged areas were considered more beneficial for biodiversity than many small areas. The main argument was that long-term species persistence becomes higher with larger areas. For recreation and water quality, there were almost no differences in estimates between these two strategies. One “land sharing” approach, retention trees, received the lowest score. The second “land sharing” approach, extended rotation, was scored higher, especially regarding recreation. This may be because extended rotations generate features of high recreational value, such as mature, thinned forests with not so much dead wood. Conclusively, we suggest a strategy of mixed conservation measures, with considerable efforts directed towards establishing and maintaining large unmanaged areas.     

Effects of population density, sex morph, and tree size on reproduction in a heterodichogamous maple, Acer mono, in a temperate forest of Japan

The effects of local population density, sex morph [protogynous (PG) or protandrous (PA)], and individual tree size on the demographic processes of seed production were investigated in a heterodichogamous maple, Acer mono Maxim. var. Marmoratum (Nichols.) Hara f. dissectum, in a temperate forest of Japan. As the distance from conspecific reproductive adults increased, the percentage of immature seed fall and empty seeds increased significantly, indicating higher pollination success along with local population density. Although the difference was not distinct, pollination success was affected by the local population density of the reciprocal sex morph rather than that of both sex morphs. The trees at higher local population density sites suffered higher seed mortality due to predation and decay, and tended to produce smaller seeds. Thus, the impacts of local population density operated both positively and negatively on reproduction. As a factor of individual traits, tree size scarcely affected any demographic processes. On the other hand, sex morph did affect pollination success. Trees of PG type had lower immature seed fall than those of PA type, suggesting that the former has higher efficiency of pollen acceptance than the latter. The results on seed demography presented here partly support previous suggestions that heterodichogamous plants exhibit reciprocal cross-pollination and gender specialization as reproductive traits.     

野化培训大熊猫采食和人为砍伐对拐棍竹无性系种群更新的影响

亚高山竹类占据着野生大熊猫(Ailuropoda melanoleuca)食物组分的99%,竹子的生命周期与大熊猫的生活史密切相关,竹子的更新和生长直接影响着大熊猫的生存与保护.为了弄清大熊猫的采食利用和人为砍伐是否促进或制约竹子的繁殖更新,应用样方法、定位观察法,连续研究了卧龙自然保护区大熊猫栖息地内野化培训大熊猫采食、人为砍伐和对照样方中拐棍竹无性系种群的更新动态.结果表明,在相同种群数量和环境条件的基础上(p>0.05),被大熊猫采食竹子的比例为67.07%,致死率29.07%;人为砍伐竹子的比例为65.67%,致死率46.68%,可见与大熊猫采食相比,砍伐更为影响拐棍竹种群的生存.从出笋数量来看,不同处理方式有利于拐棍竹无性系种群的更新(p<0.05),尤其是人为砍伐措施大大提高了竹子的出笋率,但人为砍伐样方的竹笋质量(地径和株高生长)却远低于大熊猫采食和对照样方,未能达到大熊猫觅食的选择利用标准.不同年份之间,各种处理方式下的拐棍竹出笋数量波动较大(p=0.006～0.035),并随着恢复时间的延长,逐渐趋于相似(2007,p=0 825).不同处理方式之间,拐棍竹无性系种群的年补充率,各年份均具有显著性差异(p<0.05,除2007年外),年死亡率仅2003年和2004年有明显的差异(p<0.05),2005～2007年均不显著(p>0.05).拐棍竹无性系种群的年补充率与年死亡率之间表现出年补充率﹥年死亡率的格局(p<0.05),唯有大熊猫采食样方的2004年和2005年、人为砍伐和对照样方的2005年的年死亡率略高于年补充率(p>0.05),这表明拐棍竹无性系种群对大熊猫采食和人为砍伐具有无性系整合的补偿效应.     

新疆艾比湖湿地自然保护区植物的生态分组

应用列联表的χ~2检验和Spearman相关系数研究了艾比湖湿地自然保护区植物的种间联结性和相关性.依据测定结果,将艾比湖湿地自然保护区的植物划分为4个生态种组:梭梭+盐节木+白麻+盐爪爪+琵琶柴+碱蓬+花花柴+骆驼刺+绢蒿+白刺+芦苇、小獐茅+多枝柽柳+滨藜+小叶碱蓬+盐豆木+鹅绒藤+盐穗木、胡杨+白梭梭、奶浆草+甘草+西北天门冬+赖草+罗布麻.各生态种组内,物种间具备最大的种问联结性和相关性.长期的演替过程使各生态种组对生境有最大的适应能力,各自分别生活于过渡带的盐化平原低地、湖滨盐沼地、荒漠和荒漠优势种间的阳斑.今后在艾比湖湿地自然保护区植物的保护和恢复中,以整个生态种组的角度出发较单个植物的保护和恢复更为有效.     

大熊猫的生境选择特征

基于王朗国家级自然保护区1997—2009年的连续监测数据,利用分布频率法和Bai-ley法,从地形因子、森林群落结构和主食竹3个方面研究了大熊猫的生境选择特征.结果表明:王朗国家级自然保护区的大熊猫对生境具有明显的选择性.在地形上,多选择海拔在2500～3000 m的山体脊部、上部和中部的均匀坡和凸坡,坡向西南,坡度在6°～30°,与水源距离>300 m的环境;森林群落结构上,多选择起源为次生林、针阔混交林,微生境为竹林的生境,乔木平均高度在20～29 m,灌木盖度在0～24%;主食竹多选择平均高度在2～5 m,竹丛盖度>50%,混生,生长状况良好的缺苞箭竹.     

Do vine species in neotropical forests see the forest or the trees?

Questions: Is the occurrence of vine species in neotropical rain forests primarily determined by properties of the forest (environmental factors), by properties of the trees (tree species or tree size) or are vines randomly distributed? Location: Maya Biosphere Reserve, Guatemala. Methods: In five 1‐ha plots that span variation from unlogged forest to forest impacted by recurrent human disturbance we recorded the presence of all climbing vine species on every tree. The presence of all free standing vine species and 11 environmental variables were recorded in 100‐m² subplots. The relationship of host tree diameter and host tree identity on single tree vine species richness was investigated by GLM modelling. Partial redundancy analyses were used to partition the variation in vine species composition on two sources: environmental factors and tree species identity. Results: Single tree vine richness increased with increasing host tree DBH and differed significantly among host species. For climbing vines, the ratio of variation in subplot presence explained by tree species and by environmental variables was ca. 4:1 (in the most disturbed logged plots slightly lower), for free standing vines this ratio varied from 1:2 in the most disturbed logged plots to 9:1 in reserve plots, while a ratio of ca. 1:1 was found for all plots analysed together. Conclusion: Different tree species have different probabilities of being infested by vines. Vines see both the forest and the trees; the environment is more important in earlier developmental stages, properties of individual trees become more important from the time vines start to climb.     

甘肃东大山自然保护区岩羊生态行为的初步观察

2004年7月和8月,通过样线调查、野外直接跟踪观察和瞬间取样的方法,对东大山自然保护区岩羊(Pseudois nayaur)的种群结构和生态行为进行了初步研究。在观察到的720只岩羊中,719只组成了50个群,最大的群82只,最小的群2只,平均群大小(14.38±15.83)只(n=50)。雌雄性比为1∶0.63,成年雌体、亚成体和幼体之比是1∶0.4∶0.24。岩羊的昼间活动中,上午和下午各有一个瞬间觅食高峰,分别在6:30时和15:30时,中午有一段较长时间的休息期。通过对一个46只岩羊群连续12 d的野外跟踪观察,发现该岩羊群昼间的活动范围基本上在1.47 km2内。对152个自然死亡的雄性岩羊头骨的分析表明,东大山雄性岩羊的自然死亡年龄在7.5~11.5龄,其中9.5龄是其自然死亡的高峰。     

白水江自然保护区糙花箭竹天然林生物量与生产力的初步研究

 本文根据样方上测定糙花箭竹的地径、茎高、密度、茎重、枝条重、叶重和鞭系重资料,研究竹林生物量和生产力,并建立回归数学模型为：茎重Ws=160.942+0.227(D2NH) p<0.001 枝条重WB=76.008+0.039(D2NH) p<0.001 叶重WL＝80.643+0.051(D2NH) p<0.001 鞭系重WR=285.554+0.074(D2NH) p<0.001由方程估测出天然糙花箭竹林的各器官干重分别为茎7.558,枝条1.782,叶2.143,鞭系4.795t／ha。总生物量为16.278t／ha,平均净生产量为3.256t／ha。     

黄龙大熊猫种群数量及年龄结构调查

１９９６年６￣１０月,在野外采用路线－聚类法对黄龙寺自然保护区内大熊猫种群数量进行了调查。结果表明：保护区内现有大熊猫２３只,竹林内生态密度为０．４３９只／ｋｍ＾２。此外,首次采用了离差平方和聚类的方法,将该种群划分为４个年龄组。其中幼年组个体上占１３．３３％,青年组个体占６．６７％,成年组个体占６０％,老年组个体占２０％。最后还对结果进行了讨论。并提出了保护措施。     

武夷山杉木林凋落物动态初探

用起伏型时间序列法对武夷山国家级自然保护区杉木林凋落物月动态进行模型,结果令人满意,说明起伏型时间序列分析可应用于森林凋落物动态模拟。