Conservation of forest biodiversity and ecosystem properties in a pastoral landscape of the Ecuadorian Andes

High Andean cloud forests are home to a diversity of unique wildlife and are important providers of ecosystem services to people in the Andean regions. The extent of these cloud forests has been widely reduced through conversion to pasture for livestock, which threatens the forests’ ability to support biodiversity and provide ecosystem services. This paper explores whether impacts on woody plant biodiversity and four ecosystem properties (woody plant species richness, juvenile timber tree abundance, soil organic matter content and soil moisture) from converting forest to pasture can be mitigated if some woody forest vegetation is maintained within pastures. Woody vegetation in pastures was found to conserve those woody plant species that are more tolerant to exposure and grazing, but conservation of the high montane cloud forest community required areas of forest from which livestock were restricted. The sampled sites clustered according to woody plant species cover; these clusters represented a gradient from pasture with patches of shrubs to mature forest. Clusters differed in both woody plant species richness and number of juvenile timber trees whereas soil organic matter and soil moisture were observed to be similar among all clusters. This suggests that the different habitats may have some equivalent ecosystem properties. We conclude that the presence of woody vegetation in pastures may reduce some of the impacts of converting forest to pasture, but should not be considered a substitute for protecting large areas of forest, which are essential for maintaining woody plant species diversity in high Andean cloud forest.     

Carbon storage of a subtropical forest ecosystem: a case study of the Jinggang Mountain National Nature Reserve in south-eastern China

The carbon cycle of forest ecosystems plays a key role in regulating CO2 concentrations in the atmosphere. Research on carbon storage estimation of forest ecosystems has become a major research topic. However, carbon budgets of subtropical forest ecosystems have received little attention. Reports of soil carbon storage and topographic heterogeneity of carbon storage are limited. This study focused on the Jinggang Mountain National Nature Reserve as an example of a mid-subtropical forest and evaluated soil and vegetation carbon storage by field sampling combined with GIS, RS and GPS technology. We classified the forest into nine forest types using ALOS high-resolution remote sensing images. The evergreen broad-leaved forest has the largest area, occupying 26.5% of the total area, followed by coniferous and broad-leaved mixed forests and warm temperate coniferous forest, occupying 24.2 and 22.9%, respectively. The vegetation and soil carbon storage of the whole forest ecosystem were 1,692,344 and 5,514,707 t, with a carbon density of 7.4 and 24.2 kg/m^2, respectively, which suggests that the ecosystem has great carbon storage capacity. The topographic heterogeneity of the carbon storage was also analysed. The largest vegetation storage and soil storage is at 700–800 and 1000–1100 m, respectively. The vegetation carbon storage is highest in the southeast, south and southwest.     

中国南方石灰岩(喀斯特)生态系统及生物多样性特征

通过一些具体的喀斯特生态系统及其生物多样性研究案例,探讨了中国南方喀斯特生态系统及其生物多样性组成,阐明了以下特征:1. 中国南方喀斯特生态系统独特,包括地上生态系统和洞穴(地下)生态系统,地上生态系统具有独特的植被和生物多样性,洞穴生态系统具有丰富的特有动物类群;2. 喀斯特生境植被类型多样,植物群落远比同地区非喀斯特生境丰富;3. 喀斯特地区生物多样性极其丰富,其植物种类可以占到地方植物区系总种数的30%～40%;4. 喀斯特生境多珍稀濒危和保护动植物类群,特有种亦丰富;5. 喀斯特生境植物区系岩溶专有种约占10%,岩溶特征种(岩溶专有种+岩溶适宜种)可以占到其植物区系总种数的20%～30%.     

Tree regeneration in gap-understory mosaics in a subtropical Shorea robusta(Sal) forest

Spatial variation in tree-regeneration density is attributed to the specialization of tree species to light availability for germination and growth. Light availability,in turn, varies across the gap-understorey mosaic. Canopy gaps provide an important habitat for the regeneration of tree species that would otherwise be suppressed in the understory. In subtropical forests, there is still a knowledge-gap relating to how canopy disturbances influence tree-regeneration patterns at local scale, and if they disproportionately favor regeneration of certain species. We aim to analyze whether canopy gaps promote tree regeneration, and tree species are specialized to gaps or understory for germination and growth. We sampled vegetation in 128 plots(0.01 ha), equally distributed in gaps and below canopy, in two subtropical Shorea robusta Gaertn.(Sal) forests in Nepal, recording the number of tree seedlings and saplings in each plot. We compared the regeneration density of seedlings and saplings separately between gaps and the understorey. The mean densities of seedlings and saplings were higher in the gaps at both sites;although there was no difference in the seedling density of the majority of the species between the habitats. No species were confined to either gap or understorey at the seedling stage. We conclude that gaps are not critical for the germination of tree species in Sal forests but these are an important habitat for enabling seedlings to survive into saplings. The classification of trees into regeneration guilds mainly based on germination does not apply to the majority of tree species in subtropical Sal forests. Our results reaffirm that gap creation promotes tree regeneration by favouring seedling survival and growth and can influence forest management for conservation, as well as for plantations.     

Seed dispersal phenology and dispersal syndromes in a subtropical broad-leaved forest of China

This study describes the dispersal phenology and syndromes in Gutianshan 24 ha plot in a subtropical broad-leaved forest of China. The 130 0.5 m² seed traps collected 69,115 mature seeds, representing 27 species (belonging to 24 genera, and 15 families) in 12 months. One marked peak in the number of seeds and species during the year was found in dry season (November). Zoochory was the most common dispersal syndrome (70.4%), followed by anemochory (18.5%), ballistic dispersal (11.1%). Among fruit types, berry (33%), capsule (22%), nut (18%), and drupe (11%) were common in the subtropical evergreen forest. In fruit color, brown was the commonest (40%), followed by dark brown (30%), black (15%), red (11%), and yellow (4%). Overall, the community level seed rain study revealed that one marked peak in seed number occurred in the middle of dry season; zoochory was the principal dispersal mode of woody plants in subtropical forest, and dry seasons favor seed dispersal by animal and wind.     

Deposition pattern of precipitation and throughfall in a subtropical evergreen forest in south-central China

The effects of dry deposition, canopy leaching, precipitation ion concentration, and precipitation H⁺ concentration on net throughfall flux (NTF, throughfall minus bulk precipitation) were evaluated on a seasonal basis by using a multiple regression analysis approach based on an observation period of 4 years in Shaoshan subtropical mixed evergreen forest, south-central China. Regression analysis results indicated that the estimated canopy exchange flux was the dominant factor regulating the NTF and the calculated dry deposition was a minor term. The seasonal dry deposition of base cations accounted for 15%–43% of the NTF. The NTF analysis showed that K⁺, Ca²⁺, Mg²⁺, Na⁺, and weak acids in throughfall were derived from foliar leaching and the canopy uptakes of H⁺, NH₄ ⁺, and NO₃ ⁻ were from precipitation. The retention rate of proton (H⁺ and NH₄ ⁺) in the canopy was close to the canopy leaching rate of base cations when corrected for weak acids because weak acid-induced canopy leaching did not exchange with protons, which suggested that the canopy leaching processes neutralized acid precipitation in Shaoshan forest.     

中国森林生物多样性价值核算研究

我国森林生物多样性高度丰富 ,有必要进行价值核算。首先对我国的森林生物多样性资源进行了分类 ,并按分层抽样调查的方法选取了 9个样点 ,采用市价法和机会成本法分别对我国的森林生物多样性的价值进行了核算 ,其结果分别为 6 70 6 5 .2 7亿元和 72 891.5 0亿元。最后根据收益最大化法计算了最优贴现率为5 .5 % ,再根据经济控制论中一维波的方法对核算误差进行了处理 ,得出我国森林生物多样性的核算价值为70 30 8.42亿元。     

Deposition patterns in bulk precipitation and throughfall in a subtropical mixed forest in central-south China

The chemistry and deposition pattern in bulk precipitation andthroughfall (TF) were examined and evaluated based on the 3-yearobservations in Shaoshan subtropical deciduous-conifer mixedforest in central-south China. The TF chemistry was notablychanged when passing through canopies, which probably was attributedto the dry deposition (DD) on leaf surface and the canopy exchanges.Base cations' (Ca²⁺, Mg²⁺ and K⁺) fluxes were significantlyenriched in TF, in particular for K⁺. The annual K⁺ canopy exchangewas 12 times larger than DD, and canopy exchange of Ca²⁺, Mg²⁺and K⁺ was four times as high as the DD. The canopy exchangeof base cations in association with weak acid accounted for28.4 per cent of total leached base cations, which was one ofthe important factors to modify the TF chemistry.     

Biomass,and carbon and nitrogen pools in a subtropical evergreen broad-leaved forest in eastern China

Subtropical evergreen broad-leaved forest is the most widely distributed land-cover type in eastern China. As the rate of land-use change accelerates worldwide, it is becoming increasingly important to quantify ecosystem biomass and carbon (C) and nitrogen (N) pools. Above and below-ground biomass and ecosystem pools of N and C in a subtropical secondary forest were investigated at Laoshan Mountain Natural Reserve, eastern China. Total biomass was 142.9 Mg ha⁻¹ for a young stand (18 years) and 421.9 Mg ha⁻¹ for a premature stand (ca. 60 years); of this, root biomass was from 26.9 (18.8% of the total) to 100.3 Mg ha⁻¹ (23.8%). Total biomass C and N pools were, respectively, 71.4 Mg ha⁻¹ and 641.6 kg ha⁻¹ in the young stand, and 217.0 Mg ha⁻¹ and 1387.4 kg ha⁻¹ in the premature stand. The tree layer comprised 91.8 and 89.4% of the total biomass C and N pools in the young stand, and 98.0 and 95.6% in the premature stand. Total ecosystem C and N pools were, respectively, 101.4 and 4.6 Mg ha⁻¹ for the young stand, and 260.2 and 6.6 Mg ha⁻¹ for the premature stand. Soil C comprised 23.8–29.6% of total ecosystem C whereas soil N comprised 76.9–84.4% of the total. Our results suggest that a very high percentage of N in this subtropical forest ecosystem is stored in the mineral soil, whereas the proportion of organic C in the soil pool is more variable. The subtropical forest in eastern China seems to rapidly accumulate biomass during secondary succession, which makes it a potentially rapid accumulator of, and large sink for, atmospheric C.     

Responses of intra-annual runoff to forest recovery patterns in subtropical China

Forest recovery plays a critical role in regulating eco-hydrological processes in forested watersheds.However,characteristics of the intra-annual runoff variation associated with different forest recovery patterns remain poorly understood.In this study,three forest change periods were identified,the baseline period(1961-1985),reforestation period(1986-2000) and fruit tree planting period(2001-2016).We selected the magnitude of seasonal runoff(wet and dry seasons) and distribution characteristics,i.e.,non-uniformity coefficient(C_v),complete accommodation coefficient(C_r),concentration ratio(C_n),concentration period(C_d),absolute variation ratio(ΔR) and relative variation ratio(C_(max)).The pair-wise approach evaluated the intra-annual runoff variation characteristics between forest change periods.Results indicate that reforestation decreased wet season runoff and increased dry season runoff.In contrast,fruit tree planting increased wet season runoff and had no significant effect on dry season runoff.For intra-annual runoff distribution characteristics,reforestation significantly reduced the C_v,C_r,C_n and C_(max).Distribution of the intra-annual runoff in the fruit tree planting period was not significantly different from the baseline.We concluded that reforestation reduced the occurance of extreme water conditions in wet and dry seasons and effectively increased the stability of the intra-annual runoff.In contrast,fruit tree planting increased instability and fluctuation of the intra-annual runoff after reforestation.The characteristics of the intra-annual runoff to fruit tree planting was similar to those of the baseline.Therefore,adopting fruit tree planting practices to regulate intra-annual runoff characteristics may not be a practical approach,and impacts of different reforestation practices should be ascertained in our study region.The implications of this study should guide regional land-water management,and this study adds to the understanding of the impacts gained in forest cover on hydrology.     

我国建立森林生态效益补偿制度探析

我国森林生态效益补偿基金的建立,结束了长期以来无偿享用森林生态效益的历史,在林业发展史上具有重要的里程碑意义.文章分析了我国<森林法>和<森林法实施条例>规定的森林生态效益补偿制度,阐述我国建立森林生态效益补偿制度的重要意义和相关依据,提出完善我国森林生态效益补偿制度的建议.     

Spatial distribution patterns of Symplocos congeners in a subtropical evergreen broad-leaf forest of southern China

Studies on spatial distribution of congeneric species can supplement our understanding of species ecological processes. We analyzed population structure, spatial distribution, intra-and interspecific associations among six Symplocos tree species on a large(50 ha) plot in a subtropical, evergreen broad-leaf forest in southern China using spatial point pattern analysis methods. Our results suggested that the six Symplocos tree species were all clustered at small scales. The aggregation intensity of S. wikstroemiifolia with low abundance but relatively numerous large-diameter trees was much higher than that of the other five Symplocos species that occurred at high abundance but included few large-diameter trees. Spatial associations among the six congeners showed that 12 of 30 pairs were associated positively at small scales, and 13 of 30 pairs were unrelated. For species among different size classes, 79 of 120 pairs were not correlated, and 17 of 120 pairs were associated positively. These results showed insufficient evidence for interspecific competition and congeneric Symplocos species commonly coexist within subtropical plant communities. The spatial patterns of Symplocos species and their correlations changed with size(DBH) class and were simultaneously affected by spatial scales; the intensity of their aggregation and association decreased with increasing area of the sample plot.     

A fuzzy logic-based approach for evaluating forest ecosystem service provision and biodiversity applied to a case study landscape in Southern Germany

European Journal of Forest Research - In the field of assessing forest ecosystem service provision and biodiversity, there seems to be a gap between an existing large body of valuable expert...     

Secondary forest floristic composition, structure, and spatial pattern in subtropical China

Secondary evergreen broadleaved forests are precious remnants for biodiversity conservation and templates for sustainable management of natural forests in subtropical China. Floristic composition, size structure, and spatial pattern of dominant tree species have been investigated for a subtropical secondary evergreen broadleaved forest in the Huitong Yingzuijie National Forest Reserve, Hunan, China. The location of all trees greater than 4 cm in diameter at breast height (DBH) were mapped within a 0.96-ha plot in which species, DBH, and total tree height were recorded. Ripley’s K(t) function was used to analyze spatial patterns and associations. The secondary forest consisted of 74 tree species and 1,596 stems per hectare. A reverse-J shaped DBH classes distribution was observed for all stems and trees of later seral species whereas trees of earlier successional species were distributed irregularly. Significant aggregated spatial patterns were observed for all trees within the forest and for conspecific trees of each dominant species. This result, and a repulsive spatial pattern for interspecific trees of Choerospondias axillaries and Cyclobalanopsis glauca against other dominant tree species, support segregation hypothesis. Contributions of seed dispersal, topographic heterogeneity, and competition to spatial patterns of conspecific trees vary depending on tree species. Attractive spatial pattern among interspecific trees of Liquidambar fortunei, Liquidambar formosana, and Pinus massoniana reflects stochastic colonization of pioneer tree species and a facilitation relationship. Although deciduous species are long-lived and persist over long successional processes, they will eventually be replaced by late seral evergreen species within the secondary forest if no disturbance events occur.     

Long-term response of living forest biomass to extensive logging in subtropical China

Forest disturbance and recovery are critical ecosystem processes,but the temporal patterns of disturbance have not been studied in subtropical China.Using a tree-ring analysis approach,we studied post-logging above-ground(ABG)biomass recovery dynamics over a 26-year period in four plots with different degrees of logging disturbance.Before logging,the ABG biomass ranged from 291 to 309 t ha-1.Soon after logging,the plots in primary forest,secondary forest,mixed forest and singlespecies forest had lost 33,91,90 and 100%of their initial ABG biomass,respectively.Twenty-six years after logging,the plots had regained 147,62,80 and 92%of their original ABG biomass,respectively.Over the 26 years following logging,the mean CAI(Current annual increment)were 10.1,5.5,6.4 and 10.8 t ha^-1 a^-1 and the average MAI(Mean annual increment)8.7,2.5,5.6 and 7.8 t ha^-1 a^-1 for the four forest types,respectively.The results indicate that subtropical forests subjected to moderate logging or disturbances do not require intensive management and single-species plantings can rapidly restore the above-ground biomass to levels prior to heavy logging.     

Concentrations and seasonal dynamics of dissolved organic carbon in forest floors of two plantations （Castanopsis kawakamii and Cunninghamia lanceolata） in subtropical China

The concentrations and seasonal dynamics of DOC in forest floors of monoculture plantations ofCastanopsis kawakamii and Chinese fir (Cunninghamia lanceolata) were assessed in Sanming, Fujian, China (26°11′30″N, 117°26′00″E). Forest floor samples were taken in January, April, July and October in 2002 and divided into undecomposed material (horizon Oi), partially decomposed organic material (horizon Oe), and fully decomposed organic material (horizon Oa). Upon collection, DOC concentrations of samples were analyzed by a High Temperature TOC. The results showed that the annual average DOC concentration of Chinese fir (1341.7 mg·kg⁻¹) in the forest floor was higher than that ofCastanopsis kawakamii (1178.9 mg·kg⁻¹). Difference in DOC concentrations was observed among three horizons of the forest floor. DOC concentration of forest floor in the two forests was the highest in horizon Oe. Seasonal trends of DOC concentrations in different horizons of forest floors were similar and the maximal value occurred in autumn (or winter). The concentration and temporal change of DOC in studied forests were probably related to the variation in moisture, temperature, biological activity and quantity of organic matter in the forest floor. Foundation item: This study was supported by the Teaching and Research Award program for MOE P.R.C. (TRAPOYT) Biography: ZHANG Jiang-shan (1946-), male, Researcher in Fujian Normal University, Fuzhou 350007, P.R. China. Responsible editor: Zhu Hong     

格氏栲和杉木人工林枯枝落叶层溶解有机碳浓度及季节动态

于2002 年的1 月、4 月、7 月和10 月对中亚热带格氏栲和杉木人工林(monoculture plantations of Castanopsis kawakamii and Cunninghamia lanceolata,33 年生) 枯枝落叶层(包括Oi、Oe 和Oa 层)进行了取样,并采用TOC 分析仪测定枯枝落叶层样品的溶解有机碳(DOC)浓度。结果表明,杉木人工林枯枝落叶层DOC 平均浓度(1341.7 mg·kg-1)高于格氏栲人工林(1178.9 mg·kg-1)。两种林分枯枝落叶层中,Oe 层的DOC 浓度均高于Oi 和Oa 层。格氏栲和杉木人工林枯枝落叶层不同分解层次DOC 浓度的季节变化模式基本相似,均在秋季或冬季出现最大值。枯枝落叶层DOC 浓度及季节变化与温度、湿度、生物活性及枯枝落叶层中有机质数量等有关。表2 图2 参31。     

Demographic strategies of a dominant tree species in response to logging in a degraded subtropical forest in Southeast China

Key message

The demography of pioneer tree species ( Pinus massoniana Lamb.) is significantly affected by logging in Southeast China. Logging negatively affects the population growth rate of P. massoniana , which facilitates the growth of individual trees but has no effect on reproduction probability. The survival and growth of seedlings contribute the most to population growth.

Context

Subtropical forest degradation caused by unreasonable disturbances is closely related to anthropogenic activities in Southeast China, and the frequent small-scale logging activity by local people was the dominated disturbance regime in forests in this region over the past several decades.

Aims

The objective of this study is to evaluate the demographic consequences of logging on Pinus massoniana, a pioneer tree species, at individual level (survival, growth, and fecundity) and population level (the population growth rate and size distribution) over short-term period.

Methods

The size of tree individuals was combined with vital rates using various modeling approaches based on demographic data from three annual censuses. The integral projection model (IPM) was constructed and used to conduct comparative demographic analyses.

Results

Logging negatively affected the population growth rate: from a slight expansion before logging to a moderate decline after logging. This study found a significant reduction in seedling recruitment after logging, and plant growth and mortality were slightly enhanced. The survival of seedlings greatly contributes to population growth rate compared to other life stages for both periods (before and after logging) while its relative importance decreases after logging. Seedling growth is also important to population growth, and its relative importance increased after logging. Shrinkage and fecundity have a minimal contribution effect on the population growth rate.

Conclusion

Growing plants in a nursery with a similar demography to P. massoniana could be beneficial for pioneer species regeneration in that this will improve the survival rate and growth of small individuals after logging.

     

Carbon fluxes and their response to environmental variables in a Dahurian larch forest ecosystem in northeast China

The Dahurian larch forest in northeast China is important due to its vastness and location within a transitional zone from boreal to temperate and at the southern distribution edge of the vast Siberian larch forest. The continuous carbon fluxes were measured from May 2004 to April 2005 in the Dahurian larch forest in Northeast China using an eddy covariance method. The results showed that the ecosystem released carbon in the dormant season from mid-October 2004 to April 2005, while it assimilated CO₂ from the atmosphere in the growing season from May to September 2004. The net carbon sequestration reached its peak of 112 g·m⁻²·month⁻¹ in June 2004 (simplified expression of g (carbon)·m⁻²·month⁻¹) and then gradually decreased. Annually, the larch forest was a carbon sink that sequestered carbon of 146 g·m⁻²·a⁻¹ (simplified expression of g (carbon)·m⁻²·a⁻¹) during the measurements. The photosynthetic process of the larch forest ecosystem was largely affected by the vapor pressure deficit (VPD) and temperature. Under humid conditions (VPD < 1.0 kPa), the gross ecosystem production (GEP) increased with increasing temperature. But the net ecosystem production (NEP) showed almost no change with increasing temperature because the increment of GEP was counterbalanced by that of the ecosystem respiration. Under a dry environment (VPD > 1.0 kPa), the GEP decreased with the increasing VPD at a rate of 3.0 μmol·m⁻²·s⁻¹·kPa^-1 and the ecosystem respiration was also enhanced simultaneously due to the increase of air temperature, which was linearly correlated with the VPD. As a result, the net ecosystem carbon sequestration rapidly decreased with the increasing VPD at a rate of 5.2 μmol·m⁻²·s⁻¹·kPa⁻¹. Under humid conditions (VPD < 1.0 kPa), both the GEP and NEP were obviously restricted by the low air temperature but were insensitive to the high temperature because the observed high temperature value comes within the category of the optimum range.