Lianas and self-supporting plants during tropical forest succession

Lianas (woody vines) are an important component of tropical forests, with a strong impact on forest dynamics, but their responses during forest succession have received relatively little attention. Here, we present an analysis of the changes in stem density, biomass, and species richness of lianas and self-supporting plants during tropical forest succession. We surveyed lianas ≥0.5 cm diameter at breast height (dbh) and self-supporting plants ≥2.5 cm dbh in 0.1 ha inventory plots in a chronosequence of 30 sites in northeastern Costa Rica, 23 sites on abandoned pastures 10–44 years of age, and seven sites in old-growth forest. Stem density of self-supporting plants showed no predictable chronosequence trend, but liana stem density declined significantly with forest age. Aboveground biomass of self-supporting vegetation increased rapidly during succession, with forests 31–44 years exhibiting higher levels of biomass than old-growth forests. Liana biomass accumulated more slowly, with the highest levels in old-growth sites. Species richness of self-supporting vegetation increased significantly during succession, but species richness of lianas showed no change or a slight decline with forest age, depending on the method of assessment. The differences between tree and liana responses during succession stem from the unique physiology and life history traits of lianas.     

Soil and litter fauna of cacao agroforestry systems in Bahia,Brazil

Agroforestry systems deposit great amounts of plant residues on soil and this leads to high levels of soil organic matter content and has increased soil biodiversity and improved its conservation. This study compares the distribution of meso and macrofaunal communities in soil and litter under cacao agroforestry systems and in a natural forest in the southern Bahia state of Brazil. Soil and litter samples were obtained in September 2003, February 2004, and August 2004 in five cacao agroforestry systems. The systems evaluated included: cacao renewed under Erythrina sp. (Erythrina poeppigiana) (CRE); cacao renewed under natural forest (Cabruca, CRF); an old cacao system under Erythrina sp. (OCE); an old cacao system under a natural forest system (Cabruca, OCF) and a cacao germplasm collection area (CGC). As a reference soil and litter under a natural forest (NF) was included. Organisms were collected over a 15-day period with a Berlese–Tullgren apparatus. The density and richness of total fauna varied distinctly according to sites, sampling time and material sampled (soil and litter). 16,409 of fauna were recovered from soil and litter samples and the density of total fauna was 2,094 individuals m⁻² in the litter and 641 individuals m⁻² in the soil. The richness was 11.8 in the litter and 7.5 in the soil. The cacao agroforestry systems adopted for growing cacao in the southern Bahia region of Brazil have beneficial effects on the soil and litter faunal communities, and such systems of cacao cultivation could be considered as a conservation system for soil fauna. The development of a litter layer resulted in higher abundance and diversity of soil fauna.     

Impact of deer on temperate forest vegetation and woody debris as protection of forest regeneration against browsing

A 3-year field experiment with paired exclosure (fenced areas, excluding deer) and control plots (unfenced areas, free access to deer), with two treatments with and without woody debris, was carried out at two sites in a temperate forest in eastern France. The aim of the experiment was to assess the effect of browsing by roe deer (Capreolus capreolus) and red deer (Cervus elaphus) on the diversity and richness of plant species and to test the effectiveness of using woody debris to protect seedlings and saplings from deer browsing. In presence of deer, both plant species richness and diversity were reduced the first year of the study, but this negative impact of deer then disappeared after 3 years. Deer browsing mostly affected species composition of plant communities. We observed a decrease in the abundance of preferred species such as Carpinus betulus, Rubus fructicosus, Rubus idaeus, Anemone nemorosa and Epilobium angustifolium, and palatable species such as Acer spp., Carex spp., Festuca spp. and Mycelis muralis, whereas unpalatable species such as Lamium spp., or species particularly resilient to browsing such as grasses (Brachypodium spp. and Luzula spp.) increased in abundance. The use of woody debris as protection against browsing by deer did not limit damage to seedlings and saplings of the main commercially valuable species, Abies alba and Quercus spp. Instead of limiting deer impact, use of woody debris seemed to increase the negative effect of deer browsing on regeneration in control plots relatively to those without protection.     

川中丘陵区防护林群落多样性研究

本文对川中丘陵地区主要防护林群落的物种多样性进行研究,结果表明：①该流域共有维管束植物55科,82属,88种,其科、属、种数与四川省乃至全国比较,官司河流域植物区系具有组成简单的特点;②物种丰富度,物种多样性和均匀度指数都是人工林低于天然次生林,纯林林分低于混交林分;③土壤pH值、土壤有机质、土层厚度和人为干扰是影响防护林群落多样性发育的重要制约因子,其中土壤pH值是主导因子,制约着本区防护林群浇的空间分布格局;④林木高度、郁闭度和灌、草层盖度与物种丰富度、物种多样性指数和均匀度指数相关密切,对群落多样性发育的影响较大;而林木胸径与群落多样性指数相关不明显,对群落多样发育的影响不大。     

Diversity and production of Ethiopian dry woodlands explained by climate- and soil-stress gradients

Dry woodlands cover about 14% of the total African land surface and represent about 25% of the natural vegetation. They are characterized by a seasonal climate, with a dry season of 4-7 months. Large parts of these ecosystems are degrading due to grazing, fire or exploitation by people. We studied species richness and productivity patterns of dry woodlands in Ethiopia. For such ecosystems, classic productivity and diversity hypotheses predict that species richness and productivity increase as the wet season length increases, and decrease when soil conditions create water stress. We inventoried and measured trees in 18 2-ha plots distributed in two sites, one higher altitude site with a shorter wet season than the lower altitude site. We found that the stand volume per hectare was lower in the site with a shorter wet season. Across all 18 plots we observed that stand volume decreased with soil water stress (estimated from texture and depth). This was in line with the prediction. The species richness was lower in the short-wet-season woodlands, but was unaffected by variation in soil conditions. This suggests that climate driven constraints (wet season length) set the limits to species richness, and not soil conditions. As far as we know, this study is one of the first studies that evaluated these productivity and diversity hypotheses for dry African woodlands.     

广州市森林群落特征与物种多样性研究

广州市的天然次生林,其植物种类丰富,主要的植被类型有常绿季雨林、常绿阔叶林、针阔混交林和常绿灌丛,其地带性植被为南亚热带季风常绿阔叶林;植被组成种类丰富,具有较强的热带性,主要的科有豆科、茜草科、大戟科、樟科、桑科、山茶科、壳斗科、紫金牛科、芸香科、金缕梅科、冬青科等一些以热带亚热带为分布中心的类群;根据实地调查和收集的有关资料统计,目前一些珍稀濒危植物几乎都分布在森林公园内得以很好的保护;建议将兰花40种和另外52种植物列为广州市重点保护植物。       

P transformations in cacao agroforests soils in the Atlantic forest region of Bahia,Brazil

Little is known about the phosphorus (P) fractions and P lability of agroforest soils in tropical regions, particularly those of cacao (Theobroma cacao L.) agroforests. We hypothesized that the effect of P fertilization on the distribution of P fractions in the soil based on the source-sink relationship differs for different cacao agroforestry systems. The cacao agroforestry systems studied were the following: open cacao-cabruca, closed cacao-cabruca, cacao + erythrina, mixed cacao + rubber tree, and cacao + rubber tree intercropping. A natural forest and an unfertilized pasture were used as reference systems. The P fractions were determined using the Hedley sequential extraction method, and the P transformation processes were evaluated via structural equation modeling. The impact of low P fertilizer input on the P fractions varied according to the specific environmental conditions of each cacao production system. Consequently, there was high dissimilarity among all of the cacao sites. In all of the cacao agroforestry systems, there was an increase in inorganic P (Pi), especially the labile fraction (resin-Pi and NaHCO₃-Pi), but organic P (Po) increased only in the cacao + erythrina system and in the rubber tree planting row of the cacao + rubber tree intercropping system. As a result, the fitted structural models indicated that the inter-relationships of the geochemical processes were more important for determining the P availability than the biological processes. However, the Po concentrations and relative proportion were high in all of the cacao agroforestry systems, thereby revealing the high potential of supplying P to plants via the mineralization process in the eventual removal of mineral fertilization.     

Pioneer tree responses to variation of soil attributes in a tropical semi-deciduous forest in Brazil

The occurrence of pioneer tree species inside tropical forests is usually associated with canopy openness due to disturbances. The distribution of these species under different environmental conditions, aside from light presence, can be influenced by other variables such as soil attributes, water availability, and non-arborous species presence. This work evaluates pioneer tree distribution in the Pindorama Biological Reserve, Brazil, with respect to altitude, soil attributes, and non-arborous species in 65,400-m² plots in two toposequences of semi-deciduous forest. We evaluated the physical and chemical soil attributes altitude, basal area, height, and number of individuals of tree species with diameter at breast height (DBH) ≥5 cm in a randomly chosen quadrant in each plot. Pioneer trees were characterized by the following higher occurrence species: Acacia polyphylla, Aloysia virgata, Casearia sylvestris, and Croton floribundus. Cluster analysis suggested five similar groups among sampling plots. For each group, the mean of altitude, physical and chemical soil attributes, and degree of non-arborous species infestation was calculated. Principal components analysis correlated variables with pioneer tree data. C. floribundus occurred at low altitudes at lower or higher fertility, C. sylvestris occurred in lower fertility plots, and A. polyphylla and A. virgata occurred in higher altitude plots.     

Distribution and composition of carabid beetle (Coleoptera, Carabidae) communities across the plantation forest cycle—Implications for management

If national afforestation targets are met, the proportion of area under plantation forest cover in Ireland will almost double by the year 2030 to 17%, and will consist of mostly non-native trees. There is an urgent and vital need to assess and to maximise the biodiversity potential of these forests. This study compares carabid beetle (Coleoptera, Carabidae) composition and assemblage patterns across different stages of the forest cycle, in addition to intensive grassland habitats, the habitat the plantation forest will most likely be replacing. The clearfell habitat had the highest median species richness, while the grassland habitat had the highest species diversity, but lowest species dominance. Ordination analysis revealed that the species assemblages of all stages of the forest cycle could be clearly separated from the grassland habitat, while differences were also observed between forest stages. Canonical correspondence analysis revealed that the most significant factors influencing carabid community composition were percent cover of ground vegetation and mosses, and also percent soil moisture. Differences in species with varying physical traits and microhabitat preferences were also observed between habitats, with larger, brachypterous species positively associated with increasing canopy cover and smaller macropterous species displaying the opposite pattern. The presence and abundance of forest-associated species increased with increasing plantation age, with a corresponding decrease in open habitat-associated and generalist species. The results of this study suggest that at the landscape scale, a variety of different aged forest stands would maximise the biodiversity potential of the planned afforestation.     

Spatial distribution patterns of riverine forest taxa in Brasília, Brazil

The spatial distribution of adult individuals (≥15 cm DBH) was investigated in a gallery forest of the Brasília National Park, Brazil. Four wood species, important to the Brazilian national genetic conservation programme, were chosen: Astronium fraxinifolium Schott, (Anacardiaceae); Cariniana estrellensis (Raddi) Kuntze, (Lecythidaceae); Didymopanax morototoni (Aublet) Decne. & Planch., (Araliaceae) and Hymenaea courbaril var. stilbocarpa (Hayne) Lee & Lang., (Leguminosae-Caesalpinioideae). While distribution was uneven, no relationship with gradient or togographic position could be detected, but aggregation was perceived. Stocking levels were typically low, from 0.15 to 3.31 individuals ha⁻¹.     

深圳东湖公园植物多样性研究

东湖公园为深圳市著名的综合性市政公园之一。通过实地踏查和样方调查,在园区共记录了维管植物536种(含亚种和变种),分别隶属于124科363属。其中,乡土植物399种,外来种137种。比较研究了东湖公园山地人工林、道路绿地区和专类园区绿地植物群落的物种多样性。结果表明,专类园所应用的种类相对较丰富,乔木层和草本层的物种丰富度和多样性均较高,但其灌木层的植物丰富度和草本层的均匀度相对较低。与园路区和专类园区相比,山林区植物群落的灌木多样性和均匀度较高,但草本植物种类较少。基于研究结果,总结分析了东湖公园的植物景观特色,探讨了园区山地人工林的改造、古树保护及景观安全维护问题。     

Effect of clear-cutting on the understory vegetation,soil and diversity of litter beetles in scots pine-dominated forest

Currently, the aim of modern forest management is not only timber production but also the protection of biodiversity. The initial effects of clear-cut logging on forest understory vegetation, soil and the diversity of litter beetles have been studied. We examined unstudied effects of clear-cutting disturbance on understory vascular plant species abundance, forest soils, and understory vegetation nutrients as well as beetle diversity one year after clear-cutting. Substantial changes in the prominence values and above-ground mass of forest-related vascular plant and moss species were detected. Clear-cuttings resulted in fast appearance of new light-loving plant species. The significant decrease in understory plant biomass influenced the reduction of nutrient pools in clear-cut areas after one year. The clear-cut logging negatively influenced the richness of species and the number of individuals of stenobiontic forest-related beetles in the forest litter. However, forest clear-cuttings were beneficial for eurytopic and open land species.     

Biomass,decomposition and nutrient release of Vaccinium myrtillus leaf litter in four forest stands

Biomass and nutrient transfer (N, P, K, Ca, Mg) of bilberry (Vaccinium myrtillus L.) leaf litter fall, as well as decomposition and nutrient release, were studied in four mature forest stands situated in Central and South Sweden. Bilberry leaf litter fall amounted to between 33 and 55 kg ha^‐1 yr^‐1 in the four stands. Only minor differences between sites were noted for litter concentrations of N, P and Ca, whereas K and Mg showed somewhat larger variability. Relative amounts of the five nutrient elements in the litter fall were generally in the order N > Ca > K > Mg > P. The amounts of nutrients returned to the forest floor by the annual leaf litter fall in the stands ranged from 0.4 to 0.8 kg ha^‐1 for N, 0.4 to 0.6 kg ha^‐1 for Ca, 0.2 to 0.7 kg ha^‐1 for K, 0.1 to 0.2 kg ha^‐1 for Mg and 0.04 to 0.08 kg ha^‐1 for P.

The decomposition of the local bilberry leaf litter was followed by means of litterbags during three years. At all sites there was an extremely rapid mass loss from the litter (between 45% and 54%) during the first four to five months of decomposition. After this initial phase, the decomposition rates decreased markedly and after three years the accumulated mass losses of the litters varied between 64% and 78% at the studied sites. After two and three years of decomposition, three of the sites exhibited almost similar litter mass losses whereas at the fourth site the litter was decomposed to a significantly lower degree. The pattern of nutrient release from the decomposing bilberry leaf litter differed somewhat from site to site. Minor differences were, however, noted for P, Ca and Mg while N and K were more strongly retained in the litter at one of the sites.     

紫金山两种主要林型有机物层中丝状真菌多样性

本文对紫金山两种主要林型,栓皮栎林(Quercus variabilis)和马尾松-枫香(Pinus massoniana-Liguidam barformasana)混交林的有机物层(L, F, H层及土壤淋溶A层)可培养丝状真菌多样性进行了研究。通过分离鉴定,共得到真菌67种,其中接合菌3种、子囊菌5种、半知菌类56种和未确定种3种,半知菌类最为丰富。两种林型分解真菌优势种群为链格孢(Alternaria sp.)、曲霉(Aspergillus spp.)、枝孢(Cladosporium sp.)、毛霉(Mucor sp.)、青霉(Penicillium sp.)、木霉(Trichoderma spp.)、根霉(Rhizopus sp.)、粘帚霉(Gliocladium sp.)。混交林型中真菌的种类和数量明显高于栓皮栎林。两个林型均以F层真菌种类最多,但F层之间和L层之间真菌多样性差异较大。在混交林型中从马尾松针叶上分离的真菌种类和数量比从枫香上分离得到的少; 从马尾松针叶上分离的真菌丰富度随着有机物层深度增加而增加,枫香则反之。比较两个林型以及混交林的两种落叶上真菌种类发现,随着有机物层深度的增加,真菌的种类差异性却随之减少,即同时出现在两个林型或两种针叶上的真菌种类增多。真菌种类随着分解过程的进行具有明显的演替现象。混交林型中同一层内不同落叶上分解真菌多样性的差异,表明凋落物基质的差异是决定真菌种类和数量的重要因素     

岷山区域植物多样性及其与生境关系分析

本文在建立植物种及其分布生境数据库的基础上，对世界重点生态区之一的岷山区域植物物种多样性及其与环境的关系进行了统计分析，论述了该区域植物多样性组成成分的复杂性、过渡性和地域性。结果表明，森林和林间草地是该区域物种多样性的重要生境，保护生境、保护狭窄种、保护单种科物种是该区域植物多样性保护的重要途径，并提出生态区域优先保护种概念。     

Shade over coffee: its effects on berry borer, leaf rust and spontaneous herbs in Chiapas, Mexico

The objective of this research was to determine the relationships between different ecological features of shade and the incidence of coffee berry borer, coffee leaf rust and spontaneous herbs in rustic coffee plantations in Chiapas, Mexico. Thirty-six 10 m by 10 m plots were established within coffee plantations. The following variables were measured or estimated: number of vegetation strata, percent canopy cover, direct, diffuse and total sunlight below the canopy, plant species richness and diversity, shade tree/shrub density, altitude, aspect, basal area, yields, percentage of coffee berry borer (Hypothenemus hampei Ferr), percentage of coffee leaf rust (Hemileia vastatrix Berk & Br.),percentage of spontaneous herb cover and the presence of paths and runoffs.Results showed a complex agroforestry system, composed of five strata. Coffee berry borer and coffee leaf rust incidence averages were 1.5% and 10.1%,respectively. Average spontaneous herb cover was 34.1%. Coffee leaf rust percentage correlated positively with the coffee berry borer. Number of strata of shade vegetation correlated negatively with leaf rust, while the presence of paths correlated positively with the leaf rust. Species richness and diversity correlated negatively to broad-leaf-herb cover and the presence of runoffs correlated positively to this last variable. Shade tree density (> 10cm d.b.h.) correlated negatively to linear-leaf-herb cover. Percentage of shade cover, light, coffee density, aspect, stand age, basal area and yields were not correlated to pest, disease and weeds. Results support the ecological theory that postulates that diversity and structural complexity in mixed plant systems maintain a healthy system.This revised version was published online in November 2005 with corrections to the Cover Date.     

Ecological interactions between fungi, other biota and forest litter composition in a unique Scottish woodland

The composition of forest litter and understorey layer, andfungal biomass (in terms of ergosterol) were measured in eightsubplots over a winter–spring period (January to April).The sampling site was positioned in a range of woodland habitats(variously dominated by beech, Fagus sylvatica; birch, Betulapendula x pubescens, and oak Quercus petraea) and a clear areacovered with grass (dominated by Holcus lanatus). The resultswere analysed together with data on bacteria and microinvertebratesavailable from parallel research. Levels of ergosterol in individualsubplots ranged between 50 and 160 µg g^–1 DW. Fungalbiomass decreased in March, and then increased significantlyin April. Stepwise regression models for ergosterol indicatedpositive relationships with moisture content (February), bacteria(all but February and March), flagellates (February) and plant-feedingnematodes and flies (January, overall). The relationships withroots, seeds, the collective variable ‘other microinvertebrates’(all March), amoebae (February) and fragments (March, overall)were negative, while the relationship between fungi- and microbial-feedingnematodes changed sign between February (–) and March(+). Results of analysis of covariance for fungal ergosterolwere significant only for January and the combined dataset.In January, fungi were shown to be significantly related toamoebae, bacteria and a collembolan Folsomia candida, whilethe only significant predictor returned by the overall modelwas bacteria. Correlation analysis confirmed some effects alreadynoted, and revealed a number of further interactions. The resultshighlighted the complexity of factors influencing temporal dynamicsand spatial variability of fungal biomass in forest litter.Most of the registered interactions appeared to be transient,and this should be taken into account while interpreting environmentalobservations. Interpretation of the specific relationships isgiven and implications for further research and overall ecosystemfunctioning are discussed.     

First report of botryosphaeriaceous fungi causing canker on Cedrela fissilis and leaf spots on Cariniana estrellensis in forest nursery in Brazil

Cariniana estrellensis and Cedrela fissilis are native forest species from Brazil that are widely used for arborization of parks and recuperation of degraded areas. The production of seedlings from these two forest trees in nurseries is severely affected by fungal diseases. Morphological identification, sequencing analysis of three gene regions (TEF+ACT+ITS or TEF+TUB2 + ITS) and pathogenicity tests confirmed that fungi belonging to Botryosphaeriales are the aetiological agent of the diseases. This is the first report of Phyllosticta capitalensis causing leaf spots on C. estrellensis and Botryosphaeria dothidea causing canker on C. fissilis in forest nurseries in Brazil.     

老挝过度采伐热带混合落叶林区的人工补植(英文)

人工补植通常用于增加低商业价值树种盛行的次生林中期望树种的密度。本研究评估了均格种植法(vis-à-vis gap)和行植法(line planting)2种人工补植方法,以及老挝过度采伐的热带混合落叶林中的青皮木(Vatica cinerea) 和龙脑香木(Dipterocarpus alatus)和3种豆科植物(缅茄 Afzeliax ylocarpa,大果紫檀Pterocarpus macrocarpus,酸枝木Dalbergia cochinchinensis)的表现。人工补植实验安捧在了一个随机完整的大块场地,做了7个重复。栽植7年后测定了存活率、高度和直径生长,并进行方差分析。用2种人工补植方法栽植的幼苗的存活率没有发生变化(p0.05)。然而,就直径和高度生长而言,均格种植法要比行植法效果更好。这与林冠在格间和行间块速封闭有关,这种情况在行间更加明显。在存活率,高度和直径生长方面,存在着明显的种间变异。耐阴的龙脑香科树种存活率和生长表现优于喜光树种(p0.0001)。个体的大小分布不规则,说明林下光照条件不均衡。考虑到行植法很难维持恒定线条宽度和均匀光线条件,及其每年用于清理的成本和僵硬的几何模式,我们推荐采用均格种植法。龙脑香木(Diperocarpus alatus)和青皮木(V.cinerea)可用于混合阔叶林人工补植的树种。缅茄、酸枝木和大果紫檀可作为人工林的混合树种,在较宽林隙地、直线区域和开放地种植或在火耕林幼林冠下种植。     

Burning of Amazonian forest in Ariquemes, Rondônia, Brazil: biomass, charcoal formation and burning efficiency

Biomass burning in tropical forests – the normal practice to prepare land for agriculture and ranching – has been a major source of CO₂ emitted to the atmosphere. Mass transformations by burning are still little studied in the tropics. The present study estimated parameters, such as the stock of carbon contained in the biomass, burning efficiency and the formation of charcoal and ashes in a tropical moist forest. Two sets of plots arranged in the form of ‘stars' (720 m² total) were installed in a 3.5 ha area of forest that had been felled for planting pasture at Fazenda Nova Vida, Ariquemes, Rondônia. Each ‘star' had six rays measuring 2 m × 30 m; alternating rays were designated for pre-burn and post-burn measurements. All above-ground biomass present in the plots was weighed directly before the burn in the pre-burn rays and after the burn in the post-burn rays. Pieces of wood with diameter ≥10 cm also had their biomasses estimated from volume estimates, using line-intersect sampling (LIS) in order to increase the area of sampling and to allow volume loss to be estimated as an increment based on individual pieces measured before, and after, the burn at the same point (as opposed to inferring change as a difference between independent estimates of stocks). The initial above-ground biomass (dry weight) before the burn was estimated at 306.5 ± 48.6 (mean ± SE) Mg ha⁻¹, with an additional 4.5 Mg ha⁻¹ for trees left standing. Carbon stock in the initial biomass (including trees left standing) was 141.3 (Mg C) ha⁻¹. After burning, carbon stock was reduced by 36.8% (burning efficiency). The stocks of charcoal and ash formed in the burn were, respectively, 6.4 ± 2.7 and 5.7 ± 1.0 Mg ha⁻¹. The destructive and nondestructive (LIS) methods did not differ significantly (t-test, p > 0.05) in estimating post-burn stocks of wood and charcoal. The results of this study contribute to improving the estimates of parameters needed for global carbon calculations and point to ways in which estimates of these parameters could be further improved.