This long-awaited book would seem to mark the end of classical tropical botany and phytogeography as subjects for scholarly pursuits. Since the middle of the century, when the first edition of The Tropical Rain Forest appeared, the wet tropical lowlands of the world have become an industrial battleground and, today at the end of the "Second Millennium", the future of the remaining rainforests that have evolved over millions of years looks bleak. Indeed, the book may well become "a record of what the rainforest was like in the twentieth century", as stated on its first page. This elegiac declaration not only reflects world concern about its pending extinction, but also Professor Richards' increasingly personal involvement with rainforest conservation in his later years.

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The Tropical Rain Forest: An Ecological Study

Measuring of dispersion of individuals and analysis of the distributional patterns.

Summary 1 Many authors have suggested that topography and soils are the major determinants of species distributions and community patterns at small or regional scales, but few studies addressed the patterns at mesoscales. We used Reserva Ducke (100 km 2 ) as a model to analyse the effects of soil, topography and watersheds on the variation of the herb community composition, and to determine the relative importance of the environmental factors on species composition. 2 Taxonomic groups are frequently used as surrogates in studies of biodiversity distribution and complementarity, but their efficacy is controversial. We therefore studied the correlations between the distributional patterns of three different herb groups (Marantaceae, pteridophytes and ‘others’) and their responses to environmental predictors. 3 Terrestrial herbs were sampled in 59 plots of 250 × 2 m, systematically distributed over the reserve. Plots followed isoclines of altitude, to minimize the internal variation of soil. Composition of the total herb community and of the three herb groups was summarized with PCoA. 4 Soil structure, represented by PCA axes, was the main determinant of the variation in herb composition for all groups, but slope affected only pteridophytes. Soil and topography explained less than one-third of the variance in community data. Herb composition was significantly different between watersheds, but watersheds differ only slightly in soil parameters. Our results indicate high turnover in species composition, on spatial scales of 5‐10 km in central Amazonia, which is not necessarily associated with soil change. 5 Compositional patterns of the three groups analysed were significantly correlated, but with low values for the correlation coefficient. Although composition was correlated, the responses to environmental predictors differed among groups, and the use of one group as a surrogate will miss around 50% of the variation in other groups. 6 Although important, soil and topography alone cannot predict herb community structure. Knowledge of geographical, historical or other landscape features, such as watershed morphology, may therefore be necessary to predict the turnover patterns over mesoscales. Moreover, the same factors may not have the same effectiveness as predictors of the structure of seemingly similar biological groups.

https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2745.2005.01020.x

Mesoscale distribution patterns of Amazonian understorey herbs in relation to topography, soil and watersheds

At landscape and regional scales topography is recognized as one of the most important determinants of vascular plant diversity, primarily due to the infl uence of mountains. As temperature changes markedly over the elevation ranges in mountain areas, topography off ers a wide variety of diff erent habitats as well as buff ering against climate change. However, for local vegetation, notably in lowland areas, the general importance of topography is less well recognized and the mechanisms by which it exerts infl uence on local vascular plant diversity are not comprehensively understood. In this review, we provide an overview of the evidence for the diff erent mechanisms involved in topography ' s control of local patterns in potential vegetation drivers, namely incident solar energy, wind exposure, hydrology, geochemistry, and biotic conditions. Furthermore, we review the processes through which these factors shape local terrestrial vascular plant diversity patterns and provide directions for future studies on this topic. We fi nd that topography is an important factor for local vascular plant diversity patterns in a broad range of habitats throughout the world, even in relatively fl at lowlands. However, the mechanisms involved are varied and complex. Local patterns in soil moisture seem to be aff ected by topography through more mechanisms than other topographically controlled factors and have a strong and consistent infl uence on local plant diversity. Hence, local hydrology is probably the main mechanistic factor through which topography infl uences local terrestrial vascular plant diversity patterns. Future research should focus on employing high-coverage fi ne-resolution topographic data to comprehensively explore the role of topography in controlling local dynamics over large areas. Moreover, we recommend including several diff erent habitats, particularly those in which the role of topography is poorly understood. Finally, we propose to integrate relevant functional topographic variables such as topographic wetness indices instead of simple topographic measures into future investigations.

https://www.madalgo.au.dk/fileadmin/madalgo/OA_PDF_s/J88.pdf

Topography as a driver of local terrestrial vascular plant diversity patterns

Belowground community responses to fire: meta‐analysis reveals contrasting responses of soil microorganisms and mesofauna

Small-scale spatial association of the distribution for 55 abundant tree species with two environmental factors (humus depth and surface microtopography) was examined in two 1-ha plots of a heath (kerangas) forest in Central Kalimantan, Indonesia. More than 80% of the 55 species showed a significant habitat preference in humus depth and/or relative elevation in at least one plot. In particular, ten species occurring in both plots showed a consistent significant preference for humus depth or relative elevation in the two plots. Using randomization tests, however, only five species significantly associated with humus depth and no species with relative elevation. These results suggest that edaphic and topographic factors, especially humus depth, contribute to determining local spatial distribution and floristic composition of abundant tree species in the forest.

Habitat differentiation among tree species with small-scale variation of humus depth and topography in a tropical heath forest of Central Kalimantan, Indonesia

Spread of invasive plants along trails in two national parks in West Java, Indonesia

Allometric relationships between tree dimensions, aboveground forest structure and productivity were examined in tropical heath (kerangas) forest and peatland forest in Central Kalimantan, to determine the stand level properties of these forest types growing under stressful conditions, by comparing with those in mixed dipterocarp forests. In the peatland forest, tree density, trunk diameter-height relationships and aboveground biomass differed between sites, partly due to differences in disturbance history such as the intensity of selective logging in the past. The heath and peatland forests shared common characteristics such as high leaf mass per area and long leaf residence time at the stand level. Both forest types had high wood mass increment rates (maximum of 8.2 Mg ha−1 year−1 in the heath forest and 10.9 Mg ha−1 year−1 in the peatland forest), which fluctuated greatly during and after the severe 1997–1998 drought. The results here suggest that the heath and peatland forests maintain moderately high productivity under stressful conditions, probably owing to the adaptive leaf properties. The results also suggest that the aboveground forest structure of these forest types as well as peat deposit has the potential to play a significant role in the carbon balance in an area. To be able to properly conserve these forest ecosystems, more attention must be paid to elucidating the mechanisms maintaining primary productivity of heath and peatland forests.

Forest Structure and Productivity of Tropical Heath and Peatland Forests

The ethnobotany, particularly the relationship between people and forests, of the Dolok Sibual-buali Nature Reserve Area was studied. The villages around the Nature Reserve are traditionally established away from forests and agricultural areas and are inhabited by the Batak ethnic group. Within the village, houses are built closed to each other without home-garden. The village is usually surrounded by sawah (paddy-fields), ladangs, and forests at the outer edge. Five out of 15 villages around the Dolok Sibual-buali Nature Reserve are remote and far away from the center of community activities. The magnitude of dependency on the forest products of the people in the remote villages is relatively greater than do the people in the other villages. The people in the remote villages utilize the Nature Reserve as resources for traditional medicine, home industry, and daily needs such as food, including resources of traditional food industry, fire woods and construction materials.

Ethnobotany of People around the Dolok Sibual-Buali Nature Reserve Area, North Sumatra, Indonesia.

The impact of forest fire in 1997 and 1998 on the mycorrhzae was studied at the dipterocarp forest in East Kalimantan, Indonesia. In unaffected forest more than half of total ectomycorrhizae distributed in the organic layer but in the fire-affected forest one and a half years after the fire, total amount of mycorrhizae was smaller and they were found in deeper soil. The number of morphotypes of mycorrhizae was also smaller in fire-affected forest. An artificial plantation established after clear cut and prescribed burn had the largest amount of ectomycorrhizae, but the diversity was smaller than the unaffected forest. After four years, mycorrhizae had not yet recovered in fire-affected forest although the organic layer had recovered. Pioneer species of mycorrhizal fungi (early-stage fungi) developed sporocarps around the surviving hosts in severely affected forest and this suggests the start of secondary succession of mycorrhizae. In moderately affected forest, the species composition of mycorrhizal fungi which fruited during the study was similar to those of unaffected forest. This fact suggests that such sites may be the refugia of symbionts and be important in reforestation.

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Herwint Simbolon

Papers

Habitat differentiation among tree species with small-scale variation of humus depth and topography in a tropical heath forest of Central Kalimantan, Indonesia

Spread of invasive plants along trails in two national parks in West Java, Indonesia

Forest Structure and Productivity of Tropical Heath and Peatland Forests

Ethnobotany of People around the Dolok Sibual-Buali Nature Reserve Area, North Sumatra, Indonesia.

The Impact of the 1998 Forest Fire on Ectomycorrhizae of Dipterocarp Trees and their Recovery in Tropical Rain Forests of East Kalimantan, Indonesia