椴树阔叶红松林群落主要树种径级结构研究

椴树阔叶红松林群落主要树种径级结构研究孙伟中代力民章一平（中国科学院沈阳应用生态研究所,１１００１５）ＳｔｕｄｙｏｆＤｉａｍｅｔｅｒＢｒｅａｓｔＨｉｇｈＳｔｒｕｃｔｕｒｅｏｆｔｈｅＭａｉｎＴｒｅｅｓｉｎＴｉｌｉａＢｒｏａｄｌｅａｖｅｄＫｏｒｅａｎＰ...     

Recruitment of Black Howler Fruit Trees in Fragmented Forests of Northern Belize

We examined recruitment of trees whose seeds are dispersed by black howler monkeys (Alouatta pigra) in forest fragments within the Community Baboon Sanctuary in north-central Belize. In the fragments, most other large frugivores are absent and howlers dominate the large frugivore community. Consequently, we expected to observe an increased representation of howler fruit trees among the sapling community. To test this prediction preliminarily we observed howler feeding behavior for one year and conducted adult tree and sapling transects in 6 locations where howlers were present. We sampled a seventh site where howlers were absent for vegetation only. We found that in 4 of 6 sites there were proportionately fewer howler fruit saplings when compared to adult tree samples. However, when recruitment of howler fruit trees in the 6 sites was compared to a site where howlers were absent, 11 of 12 species had relatively higher recruitment. The lack of recruitment among howler fruit trees in general likely reflects differences in responses of individual species, as well as disruptions from human activities to natural processes within the forests. The observed lower recruitment patterns of howler trees suggest that over time, the abundance of the trees will likely decline and thus affect the foraging behavior and possibly survival of howlers in the fragmented forests.     

Relations between stomatal closure, leaf turgor and xylem vulnerability in eight tropical dry forest trees

This study examined the linkage between xylem vulnerability, stomatal response to leaf water potential (Ψ_L), and loss of leaf turgor in eight species of seasonally dry tropical forest trees. In order to maximize the potential variation in these traits species that exhibit a range of leaf habits and phenologies were selected. It was found that in all species stomatal conductance was responsive to Ψ_L over a narrow range of water potentials, and that Ψ_L inducing 50% stomatal closure was correlated with both the Ψ_L inducing a 20% loss of xylem hydraulic conductivity and leaf water potential at turgor loss in all species. In contrast, there was no correlation between the water potential causing a 50% loss of conductivity in the stem xylem, and the water potential at stomatal closure (Ψ_SC) amongst species. It was concluded that although both leaf and xylem characters are correlated with the response of stomata to Ψ_L, there is considerable flexibility in this linkage. The range of responses is discussed in terms of the differing leaf‐loss strategies exhibited by these species.     

Phylogeography of the Qinghai-Tibetan Plateau endemic Juniperus przewalskii (Cupressaceae) inferred from chloroplast DNA sequence variation

The vegetation of the northeast Qinghai-Tibetan Plateau is dominated by alpine meadow and desert-steppe with sparse forests scattered within it. To obtain a better understanding of the phylogeography of one constituent species of the forests in this region, we examined chloroplast trnT-trnF and trnS-trnG sequence variation within Juniperus przewalskii, a key endemic tree species. Sequence data were obtained from 392 trees in 20 populations covering the entire distribution range of the species. Six cpDNA haplotypes were identified. Significant population subdivision was detected (G(ST) = 0.772, N(ST) = 0.834), suggesting low levels of recurrent gene flow among populations and significant phylogeographic structure (N(ST) > G(ST), P < 0.05). Eight of the nine disjunct populations surveyed on the high-elevation northeast plateau were fixed for a single haplotype (A), while the remaining, more westerly population, contained the same haplotype at high frequency together with two low frequency haplotypes (C and F). In contrast, most populations that occurred at lower altitudes at the plateau edge were fixed or nearly fixed for one of two haplotypes, A or E. However, two plateau edge populations had haplotype compositions different from the rest. In one, four haplotypes (A, B, D and E) were present at approximately equivalent frequencies, which might reflect a larger refugium in the area of this population during the last glacial period. Phylogenetic analysis indicated that the most widely distributed haplotype A is not ancestral to other haplotypes. The contrasting phylogeographic structures of the haplotype-rich plateau edge area and the almost haplotype-uniform plateau platform region indicate that the plateau platform was recolonized by J. przewalskii during the most recent postglacial period. This is supported by the findings of a nested clade analysis, which inferred that postglacial range expansion from the plateau edge followed by recent fragmentation is largely responsible for the present-day spatial distribution of cpDNA haplotypes within the species.     

河北邢台市森林公园鸟类区系调查初报

2003年3月～2005年4月对邢台市森林公园的鸟类进行了调查,共记录鸟类121种,隶属15目38科.其中留鸟27种,占总数的22.31%;夏候鸟26种,占总数的21.49%;冬候鸟10种,占总数的8.26%;旅鸟58种,占总数的47.94%.山斑鸠（Streptopelia orientalis）、珠颈斑鸠（Streptopelia chinensis）、家燕（Hirundo rustica）、白头鹎（Pycnonotus sinensis）、灰椋鸟（Sturnus cineraceus）、喜鹊（Pica pica）、大山雀（Parus major）、[树]麻雀（Passer montanus）、金翅[雀]（Carduelis sinica）、小鹀（Emberiza pusilla）等10种鸟为公园的优势鸟种.国家Ⅱ级保护重点鸟类11种,河北省重点保护鸟类11种.     

Mineral control of organic carbon mineralization in a range of temperate conifer forest soils

Coupled climate–ecosystem models predict significant alteration of temperate forest biome distribution in response to climate warming. Temperate forest biomes contain approximately 10% of global soil carbon (C) stocks and therefore any change in their distribution may have significant impacts on terrestrial C budgets. Using the Sierra Nevada as a model system for temperate forest soils, we examined the effects of temperature and soil mineralogy on soil C mineralization. We incubated soils from three conifer biomes dominated by ponderosa pine (PP), white fir (WF), and red fir (RF) tree species, on granite (GR), basalt (BS), and andesite (AN) parent materials, at three temperatures (12.5°C, 7.5°C, 5.0°C). AN soils were dominated by noncrystalline materials (allophane, Al‐humus complexes), GR soils by crystalline minerals (kaolinite, vermiculite), and BS soils by a mix of crystalline and noncrystalline materials. Soil C mineralization (ranging from 1.9 to 34.6 [mg C (g soil C)^?1] or 0.1 to 2.3 [mg C (g soil)^?1]) differed significantly between parent materials in all biomes with a general pattern of ANδ¹³C values of respired CO₂ suggest greater decomposition of recalcitrant soil C compounds with increasing temperature, indicating a shift in primary C source utilization with temperature. Our results demonstrate that soil mineralogy moderates soil C mineralization and that soil C response to temperature includes shifts in decomposition rates, mineralizable pool size, and primary C source utilization.     

热带林下人工种植阳春砂仁的生长与果实产量动态

调查了西双版纳不同海拔热带沟谷雨林和次生林下的阳春砂仁生长和果实产量动态．结果表明,西双版纳热带林下阳春砂仁自身年龄增长、林下光照不足和旱季水分胁迫影响阳春砂仁果实产量。随种植期增加,阳春砂仁果实产量和成熟植株密度降低．当林下光照水平在全日照的35％以下时,阳春砂仁果实产量随林下日照水平变化呈线性增加(P<0．05)。沟谷下方阳春砂仁果实产量显著高于上方(P<0.05)。海拔600～1000m,由于阳春砂仁的主花期从干热季3～4月推迟到雨季5月,果实产量显著增加,沟谷雨林和次生林下阳春砂仁果实产量差异不显著。因此,在海拔800～1000m沟谷中轮歇地次生林下有计划种植阳春砂仁,代替在沟谷雨林下种植阳春砂仁,既能解决沟谷雨林下光照和当地旱季水分不足对阳春砂仁果实产量的影响,又有利于热带沟谷雨林的保护。     

Effect of typhoon disturbance on fine litterfall and related nutrient input in a subtropical forest on Okinawa Island, Japan

Typhoons are frequent on Okinawa Island, southwestern Japan. The effects of typhoon disturbance on the patterns of fine litterfall and related nutrient inputs in a subtropical evergreen broad-leaved forest were studied over 5 years from May 1996 to April 2001. Annual fine litterfall averaged 7558 kg ha⁻¹ (range from 6188 to 9439 kg ha⁻¹) for six sampling plots over 5 years, which differed significantly among years (p<0.001) but not among plots (p=0.122). A seasonal maximum was most evident for leaf litter component. Woody litter fell more irregularly through the year, and peak fall varied with typhoon and windstorm. The mean ratio of annual litterfall mass of sexual organs to leaves was 0.06, much lower than that in other tropical and subtropical rain forests. Nutrient concentrations varied in litterfall components, but were not significantly different among plots. The lowest concentrations of N and P in leaf litter were observed in March, which is also the month with the greatest leaf fall. However, the highest concentrations were recorded in typhoon season. Nitrogen and P concentrations were 34% and 106% greater in the green leaves that fell during typhoons than in senescent leaves. Mean nutrient inputs by litterfall were: N 83, P 3.2, K 25, Ca 71, Mg 19, Al 12, Na 10, Fe 0.86 and Mn 3.9 kg ha⁻¹ yr⁻¹, and differed significantly among years for all elements (p<0.0005) and among plots only for K (p<0.05) and Mn (p<0.0001). Typhoon disturbance strongly affected annual fine litterfall and related nutrient inputs, which contributed an average of 30% of the annual litterfall mass, and from 30% to 39% (for different nutrient elements) of annual total nutrient inputs. The results from this study suggest that typhoon-driven maintenance of rapid cycling of P and N and their high availability in soil appears to be an important mechanism to maintain productivity in the subtropical forest on Okinawa Island.     

Effects of anthropogenic disturbance on plant diversity and community structure of a sacred grove in Meghalaya, northeast India

This study analyses the effects of anthropogenic disturbance on plant diversity and community attributes of a sacred grove (montane subtropical forest) at Swer in the East Khasi Hills district of Meghalaya in northeast India. The undisturbed, moderately disturbed and highly disturbed stands were identified within the sacred grove on the basis of canopy cover, light interception and tree (cbh 15 cm) density. The undisturbed forest stand had >40% canopy cover, >50% light interception and a density of 2103 trees per hectare, whereas the highly disturbed stand had <10% canopy cover, <10% light interception and 852 trees per hectare. The moderately disturbed stand occupied the intermediate position with respect to these parameters. The study revealed that the mild disturbance favoured species richness, but with increased degree of disturbance, as was the case in the highly disturbed stand, the species richness markedly decreased. The number of families of angiosperms was highest (63) in the undisturbed stand, followed by the moderately (60) and highly disturbed (46) stands. The families Rubiaceae, Asteraceae and Poaceae were the dominant families in the sacred forest. Rubiaceae was represented by 11, 14 and 10 species in the undisturbed, moderately disturbed and highly disturbed stands, respectively, whilst the family Asteraceae had 16 species in the moderately disturbed stand and 14 species in the highly disturbed stand. The number of families represented by a single species was reduced significantly from 33 in the undisturbed stand to 23 in the moderately and 21 in the highly disturbed stand. The similarity index was maximum (71%) between the undisturbed and moderately disturbed stand and minimum (33%) between the undisturbed and highly disturbed stands. The Margalef index, Shannon diversity index and evenness index exhibited a similar trend, with highest values in the moderately disturbed stand. In contrast, the Simpson dominance index was highest in the highly disturbed stand. There was a sharp decline in tree density and basal area from the undisturbed (2103 trees ha^–1 and 26.9 m² ha^–1) to the moderately disturbed (1268 trees ha^–1 and 18.6 m² ha^–1) and finally to the highly disturbed (852 trees ha^–1 and 7.1 m² ha^–1) stand. Density–girth curves depicted a successive reduction in number of trees in higher girth classes from the undisturbed to the moderately and highly disturbed stands. The log-normal dominance–distribution curve in the undisturbed and moderately disturbed stands indicated the complex and stable nature of the community. However, the short-hooked curve obtained for the highly disturbed stand denoted its simple and unstable nature.     

中国多孔菌一新记录种——韦氏小针层孔菌

根据中国的标本材料对中国多孔菌一新记录种———韦氏小针层孔菌 [Phellinidiumweirii(Murrill)Y .C .Dai]进行了详细描述 ,并讨论了该种与其相似种硫色小针层孔菌的区别 :该种担子果多年生 ,管孔较小 ( 5～ 7vs 4～ 5permm) ,管口全缘 ,担孢子不嗜蓝 ,只生长在柏树上。该种分布于青海省祁连山地区 ,生长在祁连圆柏上 ,造成祁连圆柏根部白色腐朽。