Ma Keping

Nature conservation is the first priority for a national park

与文化兼容的精神享受、科学研究、自然教育、游 憩和观光的机会。属于世界自然保护联盟(IUCN) 保护地(protected area)分类体系中的第二类(Dudley, 2008)。以下几个国家公园的实例可以帮助我们从不 同角度理解其概念。(1)美国黄石国家公园。这是比 较典型的案例之一, 不仅保护了大面积的自然景观 和生存其中的野生动物, 体现了自然景观无以伦比 的自然美, 而且在生物多样性监测方面也做得很出 色, 从其狼引入项目可见一斑。黄石公园的狼于 1926年灭绝, 1995年自加拿大阿尔伯塔引入14只, 1996年自加拿大不列颠哥伦比亚引入17只。在过去 近20年的时间里, 狼种群的动态一直被准确监测。 以2012年为例, 监测结果为10群83只, 较3年前减 少了15% (www.yellowstonepark. com)。(2)美国的仙 纳度国家公园(Shenandoah National Park)。自2001 年开始森林生物多样性监测项目, 已经建立了数百 个植物监测样地(面积: 50 m × 20 m); 监测植物群

Recovery dynamics of secondary forests with different disturbance inten- sity in the Gutianshan National Nature Reserve

Understanding the underlying processes of secondary forest recovery after disturbances such as logging is essential for biodiversity conservation and ecosystem rehabilitation. We surveyed 12 forest plots (1 ha in size) with different extents of anthropogenic disturbances in the Gutianshan National Nature Reserve and explored the community dynamics of secondary forest recovery by applying multivariate statistical analysis. We found significant differences in community composition among various recovery phases, whereas high similarities of community composition were observed within the same recovery phase. No significant difference in species richness was observed among recovery stages, but species richness tended to increase during the recovery process. Species evenness in Chinese fir forests was relatively low whereas no significant difference occurred in other forests. The main differences in community composition and species diversity were found in the canopy layer. Respective indicator species were found in shrubs and regeneration layers during different recovery phases. The most representative indicator species were deciduous shrubs or heliophilous trees for plantation forests of Chinese fir, evergreen shrubs or small trees for young secondary forests, sub-canopy evergreen trees for old secondary forests, and canopy species for old-growth forests, respectively. Overall, species diversity recovered rigorously. Also the life-form composition of saplings in the same recovery phase presented consistent trends in spite of complex and unpredictable changes in species composition during the recovery process.

Criteria and methods for assessing the threat status of ecosystem: Criteria and methods for assessing the threat status of ecosystem

Assessing the threat status of ecosystems is a useful tool for understanding biodiversity loss on Earth. In 2008, the International Union for Conservation of Nature (IUCN) established a working group at the fourth World Conservation Congress to develop quantitative categories and criteria for assessing ecosystem threat status. These categories and criteria were similar to those used to assess extinction risk for species. This working group strove to establish red lists of ecosystems by applying these criteria to ecosystems at local, regional, and global scales. Ecosystem red lists were designed to be complementary to species red lists for use in creating biodiversity conservation policies. The criteria used for assessment were grouped into four classes: short-term decline in distribution or ecological function, historical declines in distribution or ecological function, small current distribution with decline in distribution or ecological function, or very restricted current distribution. In this paper, we illustrate the use of these criteria for assessing ecosystem threat status; we used literature data on the areas of occupancy for four ecosystems in China’s Liaohe Delta in 1988 and 2006 to evaluate the threat status of these four ecosystems. We also discuss challenges that lie ahead for this method of assessment. Measures of ecosystem distribution and area of occupancy should be based on proper spatial scales. Appropriate quantitative methods are also needed to measure changes in ecosystem function. The final proposed assessment protocol will be presented for further discussion at the 2012 World Conservation Congress.

Comparison of fractal characteristics of species richness patterns among different plant taxonomic groups along an altitudinal gradient

This study was done using the non brown fractal model to quantify and compare the variations in the species richness of trees, shrubs, herbs and all plants along an altitudinal gradient and to characterize the dominating ecological processes that determine the variations.Two transects were sampled far away from any anthropogenic disturbances along the shady slopes of the Dongling mountains in Beijing, China. Both transects were continuous and 2 m wide, and every individual tree and shrub was recorded in each of them. Discrete quadrats of 1 m × 1 m were located along the transects A and B for estimation of the herb species richness along the altitudinal gradients. The level interval between the quadrats was 10 m and 25 m respectively. In this study, transects A and B were combined into one transect AB, and 40 m was selected as the optimal quadrat length along the altitudinal gradients for measuring the plant species richness patterns. Species richness in each quadrat was calculated using a program written in Matlab 6.0.Direct gradient analysis was used to describe the overall trends in the species richness of trees, shrubs, herbs and other plants with change in altitude, while the non-brown fractal model was used to detect more accurately their variations at various scales along the gradient. The model assumed that each class of ecological processes affecting the distribution of a variable could be represented by an independent spatial random function. Generally, ecological phenomena are determined not by a single ecological process but by multiple ones. These processes act on ecological patterns within their own spatial scales. In the non-brown fractal model, the spatial random functions are nested within a larger range of spatial scales. The relative contribution of the spatial random functions to the spatial variation of a variable is indicated by a weighting parameter that has to be greater than or equal to zero.In this paper, we reached the following results and conclusions. Firstly, the direct gradient method describes the general trends of trees, shrubs, herbs and all plants along the altitudinal gradient but is unable to provide further details on the altitudinal variations in the species richness. The non-brown fractal model brought out the altitudinal variations in the species richness of trees, shrubs and herbs at various scales and related them to the ecological processes. The sharp changes in the double-log variograms suggest that the non-brown fractal model is suitable for characterizing the altitudinal patterns in the species richness of trees, shrubs and herbs at various scales but is not appropriate for explaining the variations in the plant species richness, since no significant changes were found in the double-log variograms in this case. Secondly, for the trees, the double-log variogram was divided into two scale ranges (0–245 m and 245–570 m), with a fractal dimension of 1.83 and 1.10, respectively, implying that changes in the tree species richness were random at small scales (0–245 m) and almost linear at large scales (245–570 m) along the altitudinal gradients. This suggests that altitudinal variations in the tree species richness are dominated by short-range processes at small scales and by long-range processes at large scales. Thirdly, for shrubs and herbs, the double-log variograms exhibited three ranges (0–101 m, 125–298 m and 325–570 m), and the fractal dimensions were 1.78 and 1.97, 1.56 and 1.43, and 1.08 and 1.25, respectively. The results indicate that, as in the case of trees, species richness of shrubs and herbs are distributed randomly at small scales and change in a linear manner at large scales although variations in the herb species richness is less heterogeneous than shrub species richness at large scales. These results also indicate that species richness of shrubs and herbs change approximately like brown movement at middle scales. The results also suggest that altitudinal variations in the specie richness of shrubs and herbs are dominated by three ecological processes, short-range ecological processes at small scales, long-range ecological processes at large scales, and brown fractal processes at middle scales. Interestingly, comparisons of the variations in the species richness of shrubs and herbs reveal that shrubs and herbs present the same scale range in spatial variation in species richness but display different trends in species richness along the altitudinal gradient, i.e. the shrub species richness decreased with increasing elevation whereas the herb species richness peaked at the mid-high elevation. These patterns suggest that although the scales at which the main processes affect patterns in species richness are the same, the processes are completely different, or the processes are similar but the responses of the shrubs and herbs to the ecological processes are different. Finally, the plant species richness did not show any obvious pattern along the altitude gradient and maintained a constant fractal dimension across all scales, this is perhaps because the processes defining the patterns of plant species richness had similar weights and acted over closely related scales.

Multivariate relationship between tree diversity and aboveground biomass across tree strata in a subtropical evergreen broad-leaved forest

The correlation between primary producer diversity and the productivity (or biomass) of ecosystems is one of the most important and broadly studied relationship in ecology. Ecologists have discussed this relationship from two fundamentally different perspectives. Historically, productivity has been viewed as driver of species diversity. Recently, many studies have demonstrated that diversity can also control, rather than responds to, the production of biomass. These contrasting points of view have led to the debate about whether species diversity is the cause or the consequence of community productivity. Multivariate productivity-diversity hypothesis has been put forward to reconciling this debate. This hypothesis state that: (i) the environmental factors are the direct driver of species that can coexist within an area; (ii) the biomass of the area is directly influenced by the environmental factors that limit production; (iii) the environmental factors indirectly influenced biomass of the area via influencing the species number to coexist within the area that affects how efficiently environmental resources are converted into biomass. To date, empirical support for this hypothesis is scarce, especially for structurally complex terrestrial ecosystems. In this study, we modified multivariate productivity- diversity hypothesis to accommodate complex vertical structure of forest ecosystems, and used structural equation modeling and data from a large evergreen broad-leaved forest dynamic plot (24 hm2 in area) in subtropical China to understand the causal relationships among environmental factors, species richness, dominance and aboveground biomass. Trees were grouped into tow functional groups (overstorey and understorey) in order to improve the ability to detecting the diversity effect. The final model explained 30% and 58% of the variation in aboveground biomass of overstorey and understorey, respectively. Dominance was the most important factor in explaining the variation of aboveground biomass of overstorey, while both species richness and environment factors were the most important factors in explaining the variation of aboveground biomass of understorey. Consistent with the predictions of multivariate productivity-diversity hypothesis, (i) aboveground biomass were directly influenced by the environmental factors in both overstorey and understorey; (ii) environmental factors directly influence tree dominance and species richness of overstorey, but only directly influence species richness of understorey; (iii) environmental factors indirectly influence aboveground biomass of overstorey by influencing dominant, while indirectly influence aboveground biomass of understorey by influencing species richness. Interestingly, species richness was only important to explaining variation in aboveground biomass of understorey. This may be attributed to the low light condition in understorey, which may alleviative competition among trees of understorey. To our knowledge, this study provides the first empirical evidence supporting the multivariate productivity-diversity hypothesis in forest ecosystem thus contributes to extending the generality of this framework. Our result also highlights both dominant species and higher species richness is required to maximizing forest biomass.

Intra- and Inter-Specific Variation onFlowering and Fruiting Phenology in Gutianshan Subtropical EvergreenBroad-Leaved Forest, Zhejiang Province

Phenology, the timing of recurrent life-history events, including bud bust, leaf out, flowering, fruiting, and leaf senescence, are related to environmental conditions and species interactions. As one of the most important plant functional traits, the qualitative correlation between inter- and intra-specific phenology variation and community structure has not been investigated at the community level. We monitored both flowering and fruiting phenology for 106 species during 2012 to 2015 in a Gutianshan 24ha permanent plot in a subtropical evergreen broad-leaved forest in Zhejiang province. We used standard deviation to evaluate inter-and intra-specific phenology variation. Results showed that precipitation was the major climatic factor influencing flowering phenology; most species flowered in May at the community level; fruiting phenology reached its peaks on October. Interspecific variation of flowering phenology was larger than that of fruiting phenology. The standard deviation of the interspecific variation of flowering phenology was 52, and of interspecific variation of fruiting phenology was 41. However, intraspecific variation on flowering phenology was smaller than fruiting. At the community level, intraspecific variation on flowering and fruiting phenology was smaller than intraspecific variations. Intraspecific variation on phenology at the community level was not significantly correlated with species abundance. Intraspecific variation of flowering phenology did not have a significant relationship with flowering date. However, intraspecific variation of fruiting phenology had a significant negative relationship with fruiting date. Intraspecific variation of fruiting phenology decreased as fruiting date increased. To our knowledge, this is the first study to explore the relationship between intraspecific phenology variation and phenology date and the first to evaluate the relationship between intraspecific phenology variation and species richness. Coupling these quantitative phenological data with community structure (abundance)will extend phenological analyses to understand how changes in phenology, andresulting changes in species interactions, affect fitness, an importantconcept for understanding the lasting impacts of phenological change, traits variation, and species diversification in the context of climate change.

Advancements and prospects in forest seed rain studies: Advancements and prospects in forest seed rain studies

Seed dispersal links the reproductive cycle of adult plants with the establishment of their offspring and is widely recognized as a process that has a profound effect on the structure of tree communities. Although ecologists as early as Darwin realized the importance of seed dispersal, the scientific study of seed rain did not gain momentum until the early 1980s. A considerable amount of seed rain research has been conducted since then. Here we focused on seed rain studies of woody plants in forests. Seed rain monitoring methods are introduced, including seedtrap set, seed collection, separation, and identification. We also review recent progress in these studies—temporal and spatial variation in seed rain (seasonal, intra-annual, and spatial variations), recruitment limitation and its role in species coexistence, testing the negative density-dependent hypothesis, and comparisons between seed rain and later life history phases (soil seed bank, seedling, sapling and adult). We recommend that future studies should pay attention to conducting long-term seed rain monitoring, examining cross-site recruitment limitation, exploring whether negative density-dependence at the earliest stages of regeneration is greater in the tropics than at higher latitudes, and developing exciting new techniques including the analysis of stable isotope ratios and molecular genetic markers.