Foraging in tropical rain forests: The case of the penan of Sarawak,East Malaysia (Borneo)

Bailey et al. (1989) and Headland (1987) have recently proposed hypotheses stating that human foragers are unable to live in undisturbed tropical rain forests without some reliance on cultivated foods. The present discussion considers these hypotheses, as well as some of the evidence by which they have been tested. Four conceptual problems in the way these hypotheses have been formulated are identified: (1) assumptions about the relationship between key features of tropical forest ecosystems and human subsistence potential, (2) in-consistencies in the definition of pure foraging, (3) adherence to a dichotomy between foraging and agriculture, the result being that conscious and unconscious effects of exploitation on the demographic parameters of key resources is ignored, and (4) problems in defining the significance of ecotones. I consider the case of Penan hunter-gatherers of Borneo, a population which, by virtue of their reliance on the sago palm Eugeissona utilis, contradicts the conclusions of Bailey et al. and Headland. I consider salient aspects of Penan reliance on Eugeissona, and describe how Penan exploitation of this resource may positively effect its availability. This case is seen to provide a challenge to the hypotheses of Bailey et al. and Headland, not only in the extent to which it contradicts their conclusions but, more significantly, in what it reveals about the assumptions upon which their hypotheses are based. This points to the need for greater precision in the definition of future hypotheses about foraging in tropical forests.     

Valuing the rain forest: Economic strategies by small-scale forest extractivists in the Amazon estuary

The current interest in non-timber forest products as an economic option for the Brazilian Amazon represents a radical departure from the policies that have guided development in the region during recent decades. Despite this interest, little is currently known about the forms of resource management or economic strategies practiced by populations dependent on such resources. In this study, we measured the annual income and expenditures of ten households on Combu Island, located in the Amazon estuary near the major port city of Belém; in addition, we documented local uses and management of natural resources on the island Average annual income per household was found to be over U.S. $4000, derived primarily from the harvest and sale of non-timber forest products. The results of this study show that the combination of proximity to a major market and appropriate resource management can lead to high and apparently sustainable economic returns.Formerly Senior Researcher at the Museu Paraense Emílio GoeldiFormerly Student Fellow at the Museu Paraense Emílio Goeldi     

Extraction of non-timber forest products in the forests of Biligiri Rangan Hills,India. 1. Contribution to rural income

It is generally assumed that the sustained extraction and processing of non-timber forest products by local people can enhance their cash income and provide an alternative to tropical deforestation. However, the degree to which such products actually or may potentially contribute to rural incomes is poorly documented. We present the results of a study that seeks to evaluate the reliance of an indigenous group on non-timber forest products for cash income. Furthermore, we examine the effect of household variables on the cash income derived from collection and the price appreciation of non-timber forest products. These products account for nearly half of the gross annual income earned by the Soliga households in the Biligiri Rangan Hills of the Karnataka State in South India. Econometric models indicate that although income derived from the extraction of non-timber forest products is high in proportion to the time devoted to the collection, the extraction is not a preferred vocation. Furthermore, price appreciation for non-timber forest products varies for different products and, overall, the Soligas obtain essentially minimal wages for their extractive efforts. We discuss possible mechanisms for enhancement of Soligas’ income and the involvement of Soligas in conservation efforts.     

Morphologie,Larvalentwicklung und Haarsensillen des Tastbeinpaares der Gei\elspinneHeterophrynus longicornis Butler (Arach., Amblypygi)

Zusammenfassung Die Gei\elspinneHeterophrynus longicornis orientiert sich überwiegend mit Hilfe von cuticularen Haarsensillen. Borstenhaare und Trichobothrien treten besonders an den Beinen auf. Das zu einem Tastbein umgeformte, vielfach gegliederte 1. Beinpaar trÄgt au\erdem 5 weitere Typen von Haarsensillen- und 3 anders gestaltete cuticulare Sinnesorgane.Die Haarsensillen der verschiedenen Entwicklungsstadien der Gei\elspinne wurden licht und rasterelektronenmikroskopisch untersucht und ausgezÄhlt. Anschlie\ende elektronenmikroskopische Untersuchungen erlauben die Zuordnung folgender physiologischer Funktionen: Borstenhaare — Kontaktchemo- und Mechanorezeptoren; Trichobothrien — Mechanorezeptoren (Ferntastsinnesorgane); Porenhaare (2 Typen) — olfaktorische Chemorezeptoren; Kölbchenhaare — Chemorezeptoren i.w.S. (auch hygrosensitiv?); StÄbchenhaare (2 Typen) — Chemorezeptoren i.w.S. Die umgeformten Krallen sowie das Gruben- und das Plattenorgan sind vermutlich ebenfalls Chemorezeptoren i.w.S. (auch hygro-thermosensitiv?).Aus der Anzahl der Sensillen des Tastbeintarsus ergibt sich eine theoretische Axonzahl von 2250 an der Spitze bzw. 21 500 an der Basis. AuszÄhlungen von EM-Schnittbildern stimmen damit gut überein. Alle Fasern ( um 0,2 m) sind wahrscheinlich afferent und ziehen getrennt zum ZNS. Daneben finden sich in jedem Tarsalnerv eine oder mehrere Riesenfasern ( 10–20m), auf die kleinere Axone bereits vom Glied 1 an aufgeschaltet werden. Wahrscheinlich handelt es sich hier um ein Schnelleitsystem, das periphere Reize möglichst rasch zum ZNS bringt.Ein Vergleich mit Untersuchungen an anderen Arten macht wahrscheinlich, da\ die Ausstattung mit Sinnesorganen innerhalb der Ordnung Amblypygi sehr Ähnlich ist und damit der Ähnlichen Lebensweise der Arten entspricht.

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Morphology, larval development, and hair sensilla of the antenniform legs of the whip spiderHeterophrynus longicornis Butler (Arach., Amblypygi)

Summary The whip spiderHeterophrynus longicornis uses cuticular hair sensilla for orientation. Bristles and trichobothria occur mainly on the walking legs. The first pair of legs, which are modified appendages, bear five additional types of sensilla as well as three other sensory structures.The hair sensilla of different developmental stages were studied by light- and scanning electron microscopy for quantitative evaluations. Transmission electron microscopy permitted to attribute the following tentative functions to certain sensilla: bristles — contact chemoreception and mechanoreception; trichobothria — mechanoreception (touch-at-a-distance); porous sensilla (2 types)— olfaction; club sensilla — chemoreception (hygroreception?); rod sensilla — chemoreceptors. The modified claws, the pit organ and the plate organ are supposedly also chemoreceptors (eventually humidity and/or thermoreceptors).Based on the number of sensilla on the tarsus of a first leg we calculated a theoretical number of 2250 axons for the first tarsal segment and 21 500 axons for the level of the last tarsal segment. Actual counts done on EM-pictures yielded very similar numbers. This means that practically all nerve fibres (0.2/gmm diameter) are afferent and that all of them proceed toward the CNS. Furthermore, each tarsal nerve contains one or several giant fibres (10–20m diameter) which receive synapses from small axons already in the distalmost segment 1. We interpret this findings as a fast conduction pathway to relate peripheral stimuli quickly to the CNS.A comparison with the few studies on other Amblypygi renders it likely that their sensory equipment is rather similar, which corresponds to their similar life habits.

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Mit Unterstützung der Deutschen Forschungsgemeinschaft     

Wild yams revisited: Is independence from agriculture possible for rain forest hunter-gatherers?

The hypothesis that energy-rich wild plant foods are too scarce in rain forest to allow subsistence by foraging peoples independently of agriculture lacks a firm empirical basis. Data on availability of wild plant foods such as wild yams are sorely lacking, and where quantitative information is provided to support the hypothesis, it usually concerns extent of use of wild plant foods: low availability is tacitly inferred from low use. We explore the alternative hypothesis that extent of use underestimates availability of wild yams and other wild plant foods; these foods are present in large enough quantities to support hunter-gatherers, but have become increasingly neglected with increasing availability of cultivated plant foods. Thus, the subsistence of contemporary rain forest foraging peoples, in which extensive relationships with sedentary farmers appear to be universal, may be a somewhat distorted reflection of their subsistence in the pre-agricultural past. Drawing on data from ecology, archeology, ethnohistory, and linguistics, we argue that pygmy foraging peoples of the western Congo basin were present in rain forest environments before the advent of farming villagers.     

Comparison of an aquatic invertebrate assemblage between an old-growth natural forest and planted coniferous forest basins in a Japanese temperate region: the Kuroson stream in the Shimanto River basin

The purpose of this study is to clarify the differences in the aquatic invertebrate assemblage between the two basins that have the most common types of Japanese headstream forests – an old-growth natural forest (ONF) and a planted coniferous forest (PCF) – in the Kuroson stream of the Shimanto River basin and to find the groups that tend to inhabit either the ONF basin or PCF basin. Abundance, the number of families and -diversity were not different between the two basins. However, a cluster analysis of similarity showed differences in aquatic invertebrate assemblages between the ONF and PCF basins and that this difference was brought about by specific characteristics of some families, such as the Taeniopterygidae and Athericidae. We suggest that differences in the aquatic invertebrate assemblages between the two basins are a reflection of differences in the composition of the forest vegetation.     

Nontimber forest product gathering in Ritigala forest (Sri Lanka): Household strategies and community differentiation

Sri Lanka has a long tradition of forest product use. The relationship of people with a dry zone forest was studied using a sample of 48 households in two villages that varied in distance to the forest and access to the market. All households interviewed collected subsistence forest products and a majority of them also collected commercial products. The daily peak-season income from commercial gathering was 4.5 to 7.7 times the daily labor wage. There is a strong gender specialization, with commercial gathering dominated by men whereas subsistence gathering is almost exclusively the task of women. The average forest-derived household income in the village closer to the forest and with better market access was nearly double that of the other village. Family size as a proxy of labor availability was the main discriminating factor between those households who did and those who did not gather commercial products. A small inverse relationship between forest gathering and size of household agricultural land (particularly paddy rice) was observed. No clear relationship was found between total household income and forest derived income, contradicting the view that commercial forest gathering is an exclusive activity of the poorest households.     

Role of non-timber forest products in the economy of peripheral communities of knuckles national wilderness area of Sri Lanka: A farming systems approach

The Knuckles range of forests has been identified as a unique biological resource in Sri Lanka with much biodiversity. It is also important as a watershed which feeds the Mahaweli reservoir system. Having considered the present hazardous land-use practices such as cardamum production and shifting cultivation, the Knuckles range has been declared a national wilderness area. The Forest Department is in the process of preparing the management plan for the area. There are about 48 villages in the vicinity of the forest. This study attempts to estimate the composition of income in the peripheral communities, ticularly the extraction of non-timber forest products (NTFP) from this range of forests. Data were collected using structured questionnaires from 60 households in three villages in the vicinity of the forest. The rural economy is described using a farming systems approach and the net income contributed by each activity in the farming system was estimated. Results show that nine components of the farming system use resources from the village and the forest, with at least 47 plant species used by the villagers for different purposes. Cardamum production and shifting cultivation contribute significantly to the total income of the household, but the majority of households in the study depend upon forest resources to supply some portion of their income. Nevertheless, the monetary value of the annual income generated by NTFP is much lower than income from either cardamum production or shifting cultivation. If cardamum production and shifting cultivation are to be restricted under the conservation program, there could be additional pressure put on NTFP. Therefore, we suggest a study of the natural regen-eration capacity of selected NTFP; such information should be used in finalizing the management plan in the Knuckles range of forests.     

A method for the economic valuation of non-timber tropical forest products

By drawing on quantitative studies in social anthropology, zoology, ethnobotany, and economics we present a method for conducting an economic valuation of non-timber forest products. A review of 24 studies suggests that the median value for non-timber forest products is about $50/ha/year. We discuss problems with past studies and suggest ways to get better estimates of output quantities, marginal costs, and prices.     

Conflict of use for multi-purpose tree species in the state of Pará, eastern Amazonia, Brazil

Although diversified forest management is promoted as a strategy aimed at slowing tropical deforestation, little is known about the viability of integrating timber and non-timber forest products in the same forest management plans. In this study we offer an initial characterization of multi-purpose tree species in the State of Pará, the principal Amazonian logging region. We identify the species used for both timber and non-timber extraction, and classify these according to their commercial value. We relate multi-purpose species to their ecological traits, the type of non-timber forest use and the fraction of the tree harvested. Although a high number of species present a potential conflict of use, this conflict is only relevant in four of them: D. odorata, T. serratifolia, T. impetiginosa and H. courbaril. Nevertheless, the nature and relevance of this conflict will ultimately depend on the importance that the non-timber use has for the livelihoods of forest-dependant people, the commercial value and the ecological resilience of these species.     

Floristic, structural and seed bank diversity of a dry Afromontane forest at Mafai, central Tanzania

Flora, vegetation and seed bank were studied in a dry Afromontane forest in the Kondoa Irangi Hills, Tanzania with the objective to obtain information necessary for the promotion of conservation of this forest, which is rapidly degenerating due to human pressure. A preliminary checklist of 104 vascular plants occurring in the forest is provided. Based on 27 plots, each of 400m², the forest had the following ecological features: mean tree density 408 stems·ha^–1; basal area 66.56m²·ha^–1; Shannon and Wiener diversity 2.6406; evenness 0.7585 and species richness 31 tree species per 1.08ha. The seed bank was dominated by woody species, including mature forest tree species, and had several species in common with the standing vegetation. The forest contains species that are phytogeographically linked to Madagascan, Western and Southern African floras and also species disjunctly distributed in this forest and the Eastern Arc Mountains of Tanzania. Correspondence Analysis of tree species based on size classes showed that the timber species had declining populations, indicating the possibility of genetic erosion, while other species showed expanding or interrupted populations. Some DBH-size classes (e.g. 145.0–189.9cm) have disappeared from the forest, presumably due to their selective removal. We recommend detailed integrated floristic and faunistic studies of the forest, targeting the ecologically sensitive indicators of habitat change such as orchids, birds, reptiles and amphibians. Finally, a proposal to conserve the forest under a community-based forest conservation scheme is put forward.     

Regional specialization of the sperm membrane in the tick Amblyomma hebraeum koch (Acari: Ixodidae)

Summary The spermatozoon of Amblyomma hebraeum is about 200 m long and comprises: (1) a thick, club-shaped anterior part, about 20 m long bearing at its apex a tactile hemisphere, and (2) an elongated tail-like part, about 180 m long. The surface of the tactile hemisphere is covered by numerous bulbous expansions, attached to it by short stalks. The base of the hemisphere is surrounded by a fringe of thin motile processes; the remaining surface of the spermatozoon is covered with long cellular processes which run more or less parallel to one another.The membrane-associated particles found on the membrane beneath the cellular processes are regularly arranged as groups of parallel strands. The external surface of the so-called peripheral granules, as revealed by freeze-etching, is smooth with a very small number of particles. Internally the particles exhibit a regular hexagonal pattern which has not been observed, so far, on any other membrane of these sperm cells.The regional specialization of the spermatozoon surface membrane in relation to sperm motility is discussed. The results obtained indicate that processes of three types: (1) bulbous expansions, (2) motile processes, and (3) cellular processes are regional specializations, all engaged in aspects of sperm motility.The technical assistance of Mr. R. Haemmerle of Balzers Research Laboratories, Mrs. F. Seif and Miss C. Pugin, is gratefully acknowledged     

The economic value and sustainable harvest of plants and animals from the tropical forest: Assumptions,hypotheses, and methods

Recent studies of non-timber products from tropical rain forests have emphasized the economic value of these products and the sustainability of present harvests. Many of these studies rely upon a set of untested assumptions about the effects of harvesting upon the forest and the economic value of non-timber forest products in both the marketplace and in the daily life of rural people. These assumptions were formulated as a series of hypotheses during the workshop held in the Regional Community Forestry Training Center, Kesetsart University, Bangkok, in May 1992. The six hypotheses developed by workshop participants will be used to guide future research. As the hypotheses are tested, the data will be used to create a more realistic assessment of the sustainability and economic value of extraction of non-timber products from tropical forests.     

Gross nitrogen transformations in soils from uncut and cut boreal upland and peatland coniferous forest stands

Gross and net nitrogen (N) ammonification and nitrification were measured in soils from an uncut and recently cut upland and peatland conifer stand in northwestern Ontario, Canada. Rates of gross total inorganic N immobilization were similar to gross mineralization, resulting in low net mineralization rates in soils from all four upland and peatland conifer stands. Gross ammonification rates were variable but similar in soils from uncut and cut peatland hollows (18–19mgNkg^–1day^–1) and upland forest floor soils (14–19mgNkg^–1day^–1). Gross ammonium ( ) immobilization rates were also variable but similar to ammonification rates. Median gross nitrification rates were within 0–2mgNkg^–1day^–1 in soils from all four upland and peatland cut and uncut stands, although rates were consistently higher for the soils from the cut stands. Large variability in gross nitrification rates were observed in peatland soils, however the highest gross nitrification rates were measured in saturated peatland soils. Net rates remained low in the soils from all four stands due to high nitrate ( ) immobilization and very fast turnover (<0.2 day). Our results suggest that potential losses may be negated by high immobilization in uncut and cut boreal forest stands. This study reveals the potential for the interaction of N production and consumption processes in regulating N retention in upland and peatland conifer forests, and the resilience of the boreal forest to disturbance.     

Floristic composition, structure, and diversity of four forest plots in the Sierra Maigualida, Venezuelan Guayana

A phytosociological study was carried out in four 1-ha forest plots in the Sierra Maigualida region, Venezuelan Guayana. Density, dominance, and frequency values were calculated as well as the species and family importance values (FIVs) in each plot. A total of 65 families, 232 genera and 533 species were represented in the 4ha of forest. The number of stems 10cmdbh varied from 355 to 563, the number of species from 133 to 191, the genera from 76 to 120, the families from 38 to 51, and the basal area from 20.56 to 40.83m² per hectare. Overall the most species rich family was Fabaceae (38 species), the most numerous in total stems was Burseraceae (165 individuals), and the most dominant in terms of basal area was Sapotaceae (1367.13cm²). The most conspicuous families, as represented among the top five FIV, include Burseraceae in all four plots, Moraceae in three of the plots, and Sapotaceae in two plots. Less than 20% of the total inventory of species are represented in two or more plots. The percentages of species which are unique to a single plot range from 56 to 67%. The within-plot diversities recorded in the present study indicate that the Sierra Maiguailida harbors the richest forests thus far documented in Venezuelan Guayana. Meanwhile, the low between-plot similarity indices reinforce the notion that the species richness of this region is unusually high and suggest the need to extend collections and inventory studies.     

Implications of Livelihood Dependence on Non-Timber Products in Peruvian Amazonia

The present and future well-being of the world’s forest dwelling populations depends on their ability to gain livelihood resources from their immediate environment. Sustainable extraction of non-timber forest products has been promoted by conservationists and development agencies as a feasible strategy for forest dwellers that does not compromise the resource base. Yet surveys of actual resource use suggest that for poorer resource-dependent communities without access to markets, non-timber forest products can only ever represent a safety-net activity and a supplementary income source. Others argue that resource availability, in terms of the diversity and productivity of the forest, is the key parameter in realizing a contribution of forest products to well-being. This paper examines the scope and heterogeneity of forest product use to reveal whether resource availability necessarily provides the context for significant contributions to well-being of forest dwellers. We present data from an area of tropical rainforest, close to Iquitos in Peru, which was previously shown to have high potential value. We find, through a census survey of households within a forest reserve area, that non-timber forest products provide only a relatively small portion of income and that only a small proportion of available products are actually commercialized, despite apparent market availability. We show that the low rates of commercialization can be explained by unequal access capital assets used for extraction, to natural resources themselves, and to product markets. They are also explained by the concentration of capital-poor households on subsistence gathering activities. The value of destructive uses of forests, both logging and agriculture, remain higher than returns from non-timber products. This research demonstrates that although non-timber forest products are an important livelihood source, market integration and commercialization is not everywhere an appropriate or realistic strategy.     

A botanical inventory of a submontane tropical rainforest on Negros Island, Philippines

This paper provides a botanical inventory of a forest community in the North Negros Forest Reserve that is disproportionately valuable from a conservation perspective. The forest fragment is one of the last remaining wet tropical rainforest ecosystems in the biogeographic region of the West Visayas and an important refuge for a large number of endemic species. Using standard methods of the Philippine Plant Inventory Project we described the structure and composition of this little known forest type in the transition zone between lowland and lower montane forest. A 1 ha inventory plot 500×20m in size was established and all trees of 10cm DBH or greater were measured and permanently labeled. Subsequently, fertile specimens were collected over a period of 18 months. We found 645 individuals belonging to 92 species, 54 genera and 39 families with a combined basal area of 58.8m² and an average canopy height of 30m. This community was not dominated by dipterocarps. Species of Lauraceae, Burseraceae, Sapotaceae and Icainaceae were equally or more important. Diversity measured as Shannon–Wiener index (5.59), equitability index (0.86) and Simpson index (0.032) was high, and no single family or species dominated the plot.     

The effect of abiotic factors on foraging and oviposition success of the aphid parasitoid,Aphidius rosae

Searching patterns and oviposition success of the aphid parasitoid Aphidius rosae were analysed in different abiotic conditions (simulated wind, simulated drizzling rain, simulated shower, high temperature, low humidity, standard conditions) in the laboratory. Residence times, time allocation and oviposition success did not differ significantly between females foraging on rose shoots during periods with high temperature (>33°C) and low humidity (35%–40% relative humidity) and females searching under standard laboratory conditions (20°C, 65%–70% relative humidity, no wind). A wind speed of 2 m/s reduced the oviposition numbers significantly, and females spent much more time resting than searching for hosts. Females did not leave a shoot during wind, but departed quickly after wind had ceased. Simulated drizzling rain or simulated showers had the strongest effects on A. rosae foraging. Both types of rain prevented all foraging activities including departure from the shoot, and females laid no eggs during rain. After rain had stopped, females were mainly engaged with cleaning themselves and laid relatively few eggs compared to standard conditions. The impact of unfavourable abiotic environmental factors like wind or rain may help to explain why many parasitoids lay only a small proportion of their available eggs when foraging in the field.     

Extraction of non-timber forest products in the Forests of Biligiri Rangan Hills,India. 3. Productivity,extraction and prospects of sustainable harvest of amla phyllanthus emblica, (Euphorbiaceae)

Sustainable extraction of non-timber forest products (NTFPs) depends upon harvesting a small fraction of the total productivity. Over-exploitation can lead to a loss of biodiversity, but a low level of extraction, without value addition at the point of origin, is usually not economically feasible for extractors. Extraction and productivity levels per unit area for most non-timber forest products are unknown, nor do we have much information about value addition at various points in the marketing channels. Here we determine extraction and productivity levels for Amla trees (Phyllanthus emblica), which yield fruits that are used for a wide variety of purposes in preparation of various foods, beverages and medicines. We also present preliminary data on the price appreciation of the fruit for one of the processed products. We have determined that the current level of extraction, 60-80% of all fruits at the population level, may have a negative effect on new recruitment. We present a model for value addition that has the potential to enhance income and reduce the level of extraction. This model is currently being implemented by the Soliga community with the assistance of a non-governmental organization.     

Using suitable projects in adding value to nonwood forest products in The Philippines: The Copal (Agathis Philippinensis) trade in Palawan

Using Suitable Projects in Adding Value to Nonwood Forest Products in the Philippines: The Copal (Agathis philippinensis)Trade in Palawan. Economic Botany 58(3):476-485, 2004. The Philippines is a country that has little low-forest cover left, but it still has many useful forest species. Despite the decline of forest area and the degradation of forests, many of the poorest households, both indigenous and migrant, are pushed into the remaining forest area and depend on forest goods for their subsistence and monetary income. These goods are inevitably nonwood forest products (NWFPs) because timber extraction is now illegal in many parts of the country. The extraction of nonwood forest products, such as resin and rattan, is the only source of a cash income for many households. However, despite the long tradition of NWFP extraction in forest-edge villages, the income that collectors get from these products is still minimal. The impediments to a more equitable and efficient trade in NWFPs are examined, and possible ways of adding value locally to NWFPs are presented, using almaciga (Agathis philippinensis) resin extraction as a case study.