Role of the EXPO ’70 forest project in forest restoration in urban areas

The forest-restoration project of EXPO ’70 Commemorative Park, Japan, is an epoch-making attempt to restore a nature-oriented forest park in an urban area in which large-scale land reclamation had occurred. The objective of this paper is to review the concept, planning, and design, and the outcome so far, and discuss current aspects of creating a core natural habitat in the city of Osaka. Innovative planning policy and design methods have been used for construction of the forest-restoration project of EXPO Park. Unexpected troubles have occurred, however. After approximately 10 years severe effects of poor drainage and soil compaction on the establishment of the forest have been revealed by intensive monitoring. Partial redevelopment and soil-amendment work has therefore been conducted. These improvements seemed to have resulted in “a self-sustaining forest”, the original objective of the planning policy. After approximately 25 years, however, a second intensive monitoring program has revealed that the status of nature restoration is generally favorable in quantity but not in structure of forest communities or biodiversity. The major issues identified are excessive tree density with a single foliage layer caused by the single generation of immature forest stand, and ecological isolation from the source of nature. The EXPO forest is currently in the “Second Generation” stage; this involves management, including artificial gap regeneration, and soil seed bank introduction, with careful monitoring. The project is expected to be an ideal example of a core habitat of nature-oriented forest in urban areas achieved by adaptive management.     

Cutting the forest to see a single tree?

The development of single-molecule tools has significantly impacted the way we think about biochemical processes. Watching a single protein in action allows us to observe kinetic details and rare subpopulations that are hidden in ensemble-averaging techniques. I will discuss here the pros and cons of the single-molecule approach in studying ligand binding in macromolecular systems and how these techniques can be applied to characterize the behavior of large multicomponent biochemical systems.     

Temporary forest pools: can we see the water for the trees?

Temporary waters, in general, are fascinating habitats in which to study the properties of species adapted to living in highly variable environments. Species display a remarkable array of strategies for dealing with the periodic loss of their primary medium that sets them apart from the inhabitants of permanent water bodies. Survival of individuals typically depends on exceptional physiological tolerance or effective migrational abilities, and communities have their own, distinctive hallmarks. This paper will broadly overview the biology of temporary ponds, but will emphasize those in temperate forests. In particular, links will be sought between aquatic community properties, the nature of the riparian vegetation, and forestry practices. Quite apart from their inherent biological interest, temporary waters are now in the limelight both from a conservation perspective, as these habitats come more into conflict with human activities, and a health-control perspective, as breeding habitats for vectors of arboviruses. Traditionally, many temporary waters, be they pools, streams or wetlands, have been considered to be ȁ8wastedȁ9 areas of land, potentially convertible to agriculture/silviculture once drained. In reality, they are natural features of the global landscape representing distinct and unique habitats for many species – some that are found nowhere else, others that reach their maximum abundance there. To be effective, conservation measures must preserve the full, hydroseral range of wetland types.     

What controls the distribution of tropical forest and savanna?

Forest and savanna biomes dominate the tropics, yet factors controlling their distribution remain poorly understood. Climate is clearly important, but extensive savannas in some high rainfall areas suggest a decoupling of climate and vegetation. In some situations edaphic factors are important, with forest often associated with high nutrient availability. Fire also plays a key role in limiting forest, with fire exclusion often causing a switch from savanna to forest. These observations can be captured by a broad conceptual model with two components: (1) forest and savanna are alternative stable states, maintained by tree cover-fire feedbacks, (2) the interaction between tree growth rates and fire frequency limits forest development; any factor that increases growth (e.g. elevated availability of water, nutrients, CO(2)), or decreases fire frequency, will favour canopy closure. This model is consistent with the range of environmental variables correlated with forest distribution, and with the current trend of forest expansion, likely driven by increasing CO(2) concentrations. Resolving the drivers of forest and savanna distribution has moved beyond simple correlative studies that are unlikely to establish ultimate causation. Experiments using Dynamic Global Vegetation Models, parameterised with measurements from each continent, provide an important tool for understanding the controls of these systems.     

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.     

Don’t miss the forest for the trees! Evidence for vertical differences in the response of plant diversity to disturbance in a tropical rain forest

Ecological studies in tropical rain forests traditionally focus on trees above a threshold diameter at breast height (dbh), since ignoring plant species of the other structural compartments is believed to be an acceptable tradeoff between exhaustiveness and effectiveness. However, the consequences of missing species below a threshold dbh value have been largely neglected so far. We evaluated whether the response of species diversity of ≥10-cm dbh trees was similar to the response of other structural ensembles (namely treelets, saplings, and terricolous herbs) in a lowland tropical rain forest, to three disturbance regimes: natural gap dynamics (control), and selective logging with and without additional thinning. We studied forest vegetation composition and diversity in a 20-yr replicated field experiment comprising nine 1 ha permanent plots established in a semi-deciduous rain forest of the Congo Basin and equally distributed among the three treatments. Once corrected by stem density, species richness was similar between logged (20 years since logging) and untouched old-growth forest stands with respect of trees, but higher with respect of treelets. As disturbance intensity increased, species richness increased within sapling layers but decreased within herb layers, while species spatial turnover (beta diversity) increased in both cases. Regarding the parameters of the partitioned rarefaction curves and relative abundance distribution curves, no correlation was found between trees and any of the other structural compartments. Whilst tree and treelet species composition was similar among treatments, the understories still reflected past disturbance intensity, with a strong response of the sapling and herb layers. These results show that ecological studies based solely on tree layers (dbh ≥ 10 cm) are misleading because their response to disturbance cannot be used as a surrogate for the response of other structural ensembles. Long-lasting effects of anthropogenic disturbance on the sapling bank and the herb layer may durably influence the long-term forest dynamics. Since overstory but not understory plant communities have recovered from human disturbances 20 years after silvicultural operations, African tropical rain forest ecosystems may not be as resilient to selective logging as previously thought.     

Secondary forest buffers the effects of fragmentation on aerial insectivorous bat species following 30 years of passive forest restoration

Passive forest restoration can buffer the effects of habitat loss on biodiversity. We acoustically surveyed aerial insectivorous bats in a whole-ecosystem fragmentation experiment in the Brazilian Amazon over a 2-year period, across 33 sites, comprising continuous old-growth forest, remnant fragments, and regenerating secondary forest matrix. We analyzed the activity of 10 species/sonotypes to investigate occupancy across habitat types and responses to fragment size and interior-edge-matrix (IEM) disturbance gradients. Employing a multiscale approach, we investigated guild (edge foragers, forest specialists, flexible forest foragers, and open space specialists) and species-level responses to vegetation structure and forest cover, edge, and patch density across six spatial scales (0.5–3 km). We found species-specific habitat occupancy patterns and nuanced responses to fragment size and the IEM disturbance gradient. For example, Furipterus horrens had lower activity in secondary forest sites and the interior and edge of the smallest fragments (1 and 10 ha) compared to continuous forest, and only two species (Pteronotus spp.) showed no habitat preference and no significant responses across the IEM and fragment size gradients. Only the Molossus sonotype responded negatively to vegetation structure. We uncovered no negative influence of forest cover or edge density at guild or species-level. Our results indicate that reforestation can buffer the negative effects of fragmentation and although these effects can still be detected in some species, generally aerial insectivorous bats appear to be in recovery after 30 years of passive forest restoration. Our findings reinforce the need to protect regenerating forests while conserving vast expanses of old-growth forest.     

Quantifying the interannual litterfall variations in China’s forest ecosystems

凋落物是森林生物地化学循环和火险预测的关键参数。然而,森林凋落物如何随林龄变化仍不清楚。因此,量化森林生态系统凋落物年际变化对减少大尺度凋落物预测的不确定性至关重要。本论文基于中国人工林和次生林凋落物连续多年(≥2年)测定的数据集(N = 318),采用变异系数(CV)、变化百分比(V_P)和年际间比率量化凋落物的年际变化。研究结果表明,凋落物的年际变化随林龄增加(1–90年生)而呈下降趋势。其中,1–10年林龄的凋落物年际变化最大(平均CV = 23.51%,平均V_P= -28.59%~20.89%),其主要原因在于树木早期快速生长,即下一年与当年凋落物比率平均为1.20。11–40年林龄的凋落物年际变化逐渐减小,但CV平均值仍在18%左右,V_P平均值在-17.69%~21.19%之间。41–90年林龄的凋落物年际变化最小,CV平均值仅为8.98%,V_P平均值维持在8%左右。因此,大于40年林龄的凋落物量较低且稳定。这一结果与已有研究的认知不同：即当林龄大于30年、20年甚至15年时,森林凋落物量达到相对稳定。本研究结果将有助于我们深入理解森林凋落物生态学,并为大尺度碳收支和生物地化学循环模型提供基础。     

Beech forest communities in the Nordic countries – a multivariate analysis

In this study we present the first comprehensive multivariate analysis of beech (Fagus sylvatica) forest communities in the Nordic countries. The history of beech and beech forests in Scandinavia are described. In the north, the species is climatically restrained and, at present, restricted to Denmark and the southern parts of Sweden and Norway.More than 2000 sample plots were compiled, partly from literature, partly from new and unpublished data. The material included more than 20 studies of beech forests, often recorded by different non-standardised sampling designs. Therefore, prior to data analysis, a large number of plots had to be excluded to reduce the heterogeneity of the data. Only such sample plots were considered that showed a predominance of Fagus sylvatica in the canopy, that had a size within the interval of 16–100 m2, and that could be located by geographical coordinates. All species abundance values were transformed into simple species presences, and data from different vegetation layers were merged into one.A TWINSPAN cluster analysis resulted in 15 types. Three main communities with several sub-communities and varieties can be distinguished: (1) the Fagus sylvatica-Fraxinus excelsior-Stachys sylvatica community on the most basic and fertile soils, (2) the Fagus sylvatica-Corylus avellana-Galium odoratum community on moderately fertile and acid soils, and (3) the Fagus sylvatica-Sorbus aucuparia-Deschampsia flexuosa community on very acid and oligotrophic soils. Synonyms in the recent literature on Nordic beech forests to these communities are given. An ordination with the program DECORANA confirmed the primary significance of soil acidity and nutrient status for community differentiation.p>     

Making a living in the tropical forest: Yuquí foragers in the Bolivian Amazon

Questions concerning the availability of resources in tropical rain forests have given rise to the current debate centering on whether human subsistence based solely on foraging is possible in these biomes without agricultural subsidies. This paper takes the position that changing perspectives on ecological pattern and process in tropical forests and the significant variation among tropical forests on a worldwide as well as regional scale must be taken into consideration. Human disturbance is also proposed as a cause of dependence on agriculture by modern human foragers rather than as a necessary precondition for successful exploitation of the tropical forest. These issues are discussed against the background of a case study of the Yuquí, who, until very recently, were true foragers in the Bolivian Amazon. For the Yuquí, the sustainability of their subsistence system depended on a finegrained knowledge of their environment and the freedom of movement over a large territory to access resources within it.     

Role of vegetation in the variability of water regimes in the Šumava Mts forest

Deviations between observed and simulated discharge in the basins along the borders of the Czech Republic with Austria and Germany provide outputs which enable to follow changes in runoff. The three basins range in area from 100 to 200 km² and the experimental basin Liz with an area of 0.99 km². The selected experimental catchments are situated in or close to the National Park of the ?umava Mts. This region is described also in Tesa? et al. (2006). Results indicate that changes in runoff appear to be related to damages in forest cover caused by wind disasters and insects damages.Daily time series used for simulations are approximately 40 years long and 20 years in the experimental basin. Two different models of the rainfall — runoff process have been used for simulations and the outputs provide comparable results. The models are the conceptual model Sacramento (Burnash, 1995) and the model BROOK’90 (Federer, 1993). The second model distinguishes the details concerning evapotranspiration, including transpiration, rain and snow interception and snow and soil evaporation.The indicated runoff changes seem to be rather complex. After deforestation the volume of runoff generally increases and peak flows of floods are higher, but low flow in rainless periods show complicated courses.     

Male competition and paternity in wild chimpanzees of the Taï forest

In social animals, competition among males for mates affects individual reproductive success. The priority‐of‐access model attempts to account for the influence of demographic conditions within groups upon male reproductive success, but empirical data for testing this model are scarce. Our long‐term study of chimpanzees in the Taï National Park, Côte d'Ivoire, encompasses a period of steady decrease in community size and fluctuating numbers of competing males and sexually receptive females. These demographic changes, in combination with genetic assessment of paternity for 48 offspring from three communities, allowed us to quantify the effects of varying levels of competition upon male reproductive success. On average, the highest‐ranking male sired 50% of all analyzed offspring during a 14‐year period from 1987–2000. Competition among males strongly decreased the relative reproductive success of the alpha male, such that the alpha male's rate of success decreased from 67% with few competitors to only 38% with four or more competitors. The increasing number of synchronously receptive females in large groups also reduced the proportion of paternities by the alpha male. Thus, patterns of paternity in Taï chimpanzees fit well the predictions of the priority‐of‐access model. We also found that despite the inability of dominants to monopolize reproduction, they achieved a higher reproductive rate in large multimale groups, because these have more females and a higher infant survival rate. Varied levels of male competition within communities seem to explain differences in the reproductive success of alpha males observed in different chimpanzee populations, and in other primate species. Am J Phys Anthropol, 2006. © 2005 Wiley‐Liss, Inc.     

Does forest fragmentation cause an increase in forest temperature?

Forest fragmentation is considered by many to be a primary cause of the current biodiversity crisis. The underlying mechanisms are poorly known, but a potentially important one is associated with altered thermal conditions within the remaining forest patches, especially at forest edges. Yet, large uncertainty remains about the effect of fragmentation on forest temperature, as it is unclear whether temperature decreases from forest edge to forest interior, and whether this local gradient scales up to an effect of fragmentation (landscape attribute) on temperature. We calculated the effect size (correlation coefficient) of distance from forest edge on air temperature, and tested for differences among forest types surrounded by different matrices using meta-analysis techniques. We found a negative edge-interior temperature gradient, but correlation coefficients were highly variable, and significant only for temperate and tropical forests surrounded by a highly contrasting open matrix. Nevertheless, it is unclear if these local-scale changes in temperature can be scaled up to an effect of fragmentation on temperature. Although it may be valid when considering “fragmentation” as forest loss only, the landscape-scale inference is not so clear when we consider the second aspect of fragmentation, where a given amount of forest is divided into a large number of small patches (fragmentation per se). Therefore, care is needed when assuming that fragmentation changes forest temperature, as thermal changes at forest edges depend on forest type and matrix composition, and it is still uncertain if this local gradient can be scaled up to the landscape.     

Phenophases alter the soil respiration–temperature relationship in an oak-dominated forest

Soil respiration (SR) represents a major component of forest ecosystem respiration and is influenced seasonally by environmental factors such as temperature, soil moisture, root respiration, and litter fall. Changes in these environmental factors correspond with shifts in plant phenology. In this study, we examined the relationship between canopy phenophases (pre-growth, growth, pre-dormancy, and dormancy) and SR sensitivity to changes in soil temperature (T_S). SR was measured 53 times over 550 days within an oak forest in northwest Ohio, USA. Annual estimates of SR were calculated with a Q₁₀ model based on T_S on a phenological (PT), or annual timescale (AT), or T_S and soil volumetric water content (VWC) on a phenological (PTM) or annual (ATM) timescale. We found significant (p<0.01) difference in apparent Q₁₀ from year 2004 (1.23) and year 2005 (2.76) during the growth phenophase. Accounting for moisture-sensitivity increased model performance compared to temperature-only models: the error was −17% for the ATM model and −6% for the PTM model. The annual models consistently underestimated SR in summer and overestimated it in winter. These biases were reduced by delineating SR by tree phenophases and accounting for variation in soil moisture. Even though the bias of annual models in winter SR was small in absolute scale, the relative error was about 91%, and may thus have significant implications for regional and continental C balance estimates.     

How heterogeneous are the cloud forest communities in the mountains of central Veracruz, Mexico?

The montane forest in central Veracruz, Mexico is a hotspot of biodiversity. We asked whether lower and upper montane forests could be distinguished in this ecoregion. Variables of vegetation and seasonality in precipitation were tested across 14 sites between 1,250- and 2,550-m elevations. A total of 1,639 individuals and 128 tree species was recorded. There was a unimodal pattern in the richness of species, genera, and families; their richness was positively correlated with precipitation in the wettest quarter of the year, though there were no differences in the basal area and density. Rarefaction, species turnover, nonmetric multidimensional scaling, and a cluster histogram suggest two major groups: lower elevation forests that are less diverse, have low beta diversity and are more similar in composition, with Clethra macrophylla, Liquidambar styraciflua, and Quercus lancifolia as indicator species; and higher elevation forests that are more diverse, have high species turnover, and include forests with Quercus corrugata and Prunus rhamnoides, and forests with Fagus grandifolia, Persea americana, and Ternstroemia sylvatica as indicator species. However, other communities (an Oreomunnea mexicana at the upper site, and a limestone site in the lower forests), exemplify the high regional heterogeneity. We conclude that elevation and seasonality in precipitation produce a directional change in richness and indicator species, but not in vegetation structure. Lower montane forests differed from cloud forests at upper elevations. However, other factors should be included—mainly biogeographic affinities, historic and recent anthropogenic disturbance—to conclusively distinguish them. Montane forest can still be considered very heterogeneous and very high in beta diversity.     

On the structure and ecology of the micro-fauna in the Central Amazonian forest stream ‘Igarapé da Cachoeira’

A method was developed to sample the microfauna in open stream water and to observe its food habits over long periods in the laboratory. Evaluation of the material leads to the following conclusions:

1. The microfauna is primarily associated with submerged leaf litter. Its density in the open water is a function of water current and hence, of rainfall,
2. A considerable quantity of living and detritus-biomass is swept down-stream with each heavy rain,
3. The foodweb starts essentially with decomposing fungi and detritus, and to a much lesser extent with algae and bacteria. Protozoa and Rhabdocoela are an insignificant input into the foodweb of higher invertebrates, but their role for maintenance of water quality may be important. Prey of fishes and shrimps depends primarily on ‘primary input’, i.e. on detritus, fungi and to some extent on algae and bacteria. The role of biomass transport from forest streams into larger rivers is discussed in relation to the fauna of the periodically inundated forest (igapó).