Group Forest Certification for Smallholders in Vietnam: An Early Test and Future Prospects

Forests in Vietnam are heavily utilized resources. Some 25 million people who live in and near forests depend on timber and non-timber resources for subsistence and income. Vietnam’s timber processing industries, which are in a steep growth phase, demand raw material from the nation’s forests, but that demand greatly outstrips available, high quality supply. A national forest development strategy through 2020 calls for broad expansion of plantation forests coupled with third-party forest certification. One type of forest certification, involving certification of groups of smallholder farmers, is comparatively understudied. A recent effort to promote group forest certification in Vietnam yielded measurable benefits to stakeholders, including enhanced income streams to plantation smallholders. However, long-term challenges to group forest certification remain, including smallholders’ ability to cover recurring costs for certification – costs that are subsidized by a bilateral donor. Vietnam’s recent experience with group forest certification represents an early chapter in that nation’s ambitious plans to increase forest cover, make forests more productive through plantation forestry, and improve forest management and market access through forest certification.     

Contrasting palm species and use diversity in the Yucatan Peninsula and the Ecuadorian Amazon

We analyze the relationship between palm species diversity and diversity of palm use in two areas (Amazonian Ecuador; Yucatan Peninsula) of equivalent size but with contrasting characteristics in palm species diversity and morphology, and in the phylogenetic composition of palm flora. The areas also differ in their cultural and socioeconomic contexts. Palm use diversity is significantly higher in the Ecuadorian Amazon than in the Yucatan Peninsula and the lower species diversity of palms in the Yucatan Peninsula is not matched by a more intensive use of the fewer species found there. The taxonomic composition of the palm flora is a poor predictor of extent of use and morphological characteristics of palm species affect usefulness only in the Ecuadorian Amazon. The Yucatecans’ more limited reliance on forest products might explain the observed patterns. Ornamental palm use is an indicator of a general change in plant use patterns associated with tourism and macro-economic development in the Yucatan Peninsula. We find a positive relationship between ecosystem plant diversity and plant use diversity, but socioeconomic factors such as market integration strongly influence the use of local biodiversity. Palms represent a diverse and important natural resource that deserves further investigation to secure its sustainable management and conservation in the two studied sites, regardless of their degree of market integration.     

Diversity of palm uses in the western Amazon

We used palm knowledge to understand the interaction between people and the rainforests and the factors that influence this dynamic process. We interviewed 278 informants in 12 villages in the Pastaza and Madidi areas of the western Amazon basin. Together they used 38 different palm species for 38 different uses in six use-categories (food, construction, utensils, ritual, medicine, commercial). Euterpe precatoria, Iriartea deltoidea, and Oenocarpus bataua were best known and were mentioned as useful by 76–72% of the informants in the 12 villages. There was a great variation in number of uses and in how widespread the uses were and five of the 38 useful palms were mentioned by only one informant. Among the socioeconomic factors analyzed, the residence village influenced the informants’ knowledge of palms and their uses more than any other factor. Length of education, prosperity and for how long the informant had lived in the village were also positively correlated to how many palms and palm uses were known. Gender differences in informants’ knowledge of palm uses were not observed in our data. We suggest, that the high importance of forest products to the livelihood of the villagers, the great variation in the knowledge they possess, and the fact that the differences between villages is so great, are important elements to consider when developing management plans for the sustainable use of the rainforest resources in the western Amazon.     

Palm Harvest Impacts in North-Western South America

Tropical forests harbor thousands of useful plants that are harvested and used in subsistence economies or traded in local, regional or international markets. The effect on the ecosystem is little known, and the forests resilience is badly understood. Palms are the most useful group of plants in tropical American forests. This paper introduces a cross-disciplinary study of the effects of harvesting palm products from the tropical forests in north-western South America. The size of the resource is estimated through palm community studies in the different forest formations that determines the number of species and individuals of all palm species. The genetic structure of useful palm species is studied to determine how much harvesting of the species contributes to genetic erosion of its populations, and whether extraction can be made without harm. Almost all palm species are used in rural communities for subsistence purposes Quantitative ethno-botanical research in different forest types have identified thousands of different ways of using palms for food, construction, tool-making, etc. Although most palms are used by the person harvesting them, many are sold on local markets as fruits, fiber, tools, construction materials etc., and a few have reached larger markets, including international markets. Palm populations are managed in various ways of which some are sustainable and others are destructive. National level mechanisms that governs extraction, trade and commercialization of palm products, are used to identify positive and negative policies in relation to resilience of ecosystems.     

Edge effects on palm diversity in rain forest fragments in western Ecuador

At the edges of tropical rain forest fragments, altered abiotic and biotic conditions influence the structure and dynamics of plant communities. In Neotropical rain forests, palms (Arecaceae) are important floristic and ecological elements. Palms’ responses to edge effects appear to be idiosyncratic and to depend on the level of disturbance at edges. This paper explores how variation in forest structure at the edges of two old-growth forest fragments in a tropical rain forest in western Ecuador affects palms of different species, life-forms, and size classes. We investigate (1) how edge effects influence the relative proportion of palm adults and juveniles, (2) how distance from the forest edge affects palm density and species richness, (3) how altered forest structure along edges affects palm density. We found that at edges (1) palm communities had a lower proportion of adults relative to juvenile individuals compared to continuous forests, (2) the density of two species of palms and the overall species richness of the palm community tended to decrease toward the edges within forest fragments, and, (3) altered forest structure decreased the density of adult palms. Hence, edge effects on palms were controlled by the degree of modification of the forest structure, and by species responses to edge-related disturbance.     

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.     

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.     

Local people value environmental services provided by forested parks

Garnering support from local people is critical for maintaining ecologically viable and functional protected areas. However, empirical data illustrating local people’s awareness of the importance of nature’s services is limited; hence possibly impeding effective ecosystem (environmental)-services based conservation efforts. Using data from five protected forests in four developing Southeast Asian countries, we provide evidence that local people living near parks value a wide range of environmental services, including cultural, provisioning, and regulating services, provided by the forests. Local people with longer residency valued environmental services more. Educated as well as poor people valued forest ecosystem services more. Conservation education has some influence on people’s environmental awareness. For conservation endeavors to be successful, large-scale transmigration programs should be avoided and local people must be provided with alternative sustenance opportunities and basic education in addition to environmental outreach to reduce their reliance on protected forests and to enhance conservation support.     

Palm species richness,abundance and diversity in the Yucatan Peninsula,in a neotropical context

Species richness, abundance and diversity patterns in palm communities in the Yucatan Peninsula were compared at three sites with different forest types (semi‐deciduous, semi‐evergreen and evergreen), as well as different precipitation, geomorphology and soil depth. All individual palms, including seedlings, juveniles and adults, were identified and counted in forty‐five (0.25 ha) transects. A total of 46 000 individual palms belonging to 11 species from nine genera and two subfamilies were recorded. Palm richness, diversity and abundance were highest in the evergreen forest. Species from the subfamily Coryphoideae dominated the semi‐deciduous and semi‐evergreen forests while species from the subfamily Arecoideae dominated the evergreen forest. Seven species were found only in the evergreen forest. Chamaedorea seifrizii and Sabal yapa were found in all three forest types, while Thrinax radiata was found in the semi‐deciduous and semi‐ evergreen forests and Cocothrinax readii only in the semi‐evergreen forest. Compared to other neotropical palm communities, the richness and diversity in the Yucatan Peninsula are lower than in the western Amazon basin. Although palm richness and diversity on the Yucatan Peninsula were positively associated with precipitation, other variables, in particular soil depth and fertility as well as habitat heterogeneity (microtopography and canopy cover), need to be considered to better understand the observed patterns.     

Exploiting fruits of a threatened palm to trigger restoration of Brazil's Atlantic Forest

Recent global commitments to forest and landscape restoration in the tropics call for new management approaches that benefit both biodiversity and livelihoods of forest‐dependent people. The sustainable use of wild forest products is a promising pathway, but requires clarity about harvested species' demography and harvesters' rights. Here, we explored how the exploitation of fruits of the threatened palm Euterpe edulis, a key fruit source for wildlife in Brazil's globally important Atlantic Forest biodiversity hotspot, could trigger local community involvement in restoration. This palm has both non‐destructive (fruit) and destructive (palm heart) culinary uses, each with unique biological and resource‐use conditions. We quantified all demographic stages of this species in multiple agroforests, secondary forests, and protected areas to parameterize demographic projections of palm populations, harvest profitability, and fruit provisioning to wildlife under different management scenarios. Field observations showed a clear depression of adult palm populations in protected areas, likely due to palm heart poaching, and of intermediate size classes in agroforests, probably from weeding by farmers. Field data and demographic models reveal that in this region, agroforests and secondary forests can successfully conserve this species while providing lasting profits for farmers under most scenarios. These findings demonstrate a clear case where local stakeholders both contribute to and benefit from restoration through harvest of wild products and also highlight a potential source of income from regenerating tropical forests.     

Tibetan land use and change near khawa karpo, Eastern Himalayas

Collaborating Authors: Bee Gunn, Wayne Law, George Yatskievych, Wu Sugong, Fang Zhendong, Ma Jian, Wang Yuhua, Andrew Willson, Peng Shengjing, Zhang Chuanling, Sun Hongyan, Meng Zhengui, Liu Lin, Senam Dorji, Ana, Liqing Wangcuo, Sila Cili, Adu, Naji, Amu, Sila Cimu, Sila Lamu, Lurong Pingding, Zhima Yongzong, Loangbao, Bianma Cimu, Gerong Cili, Wang Kai, Sila Pingchu, Axima, and Benjamin Staver.TIBETAN LAND USE AND CHANGE NEAR KHAWA KARPO, EASTERN HIMALAYAS. Economic Botany 59(4):312-325, 2005. Tibetan land use near Khawa Karpo, Northwest Yunnan, China, incorporates indigenous forest management, gathering, pastoralism, and agriculture. With field-based GIS, repeat photography, and Participatory Rural Appraisal we quantitatively compare land use between higher and lower villages, and between villages with and without roads. Households in higher elevation (> 3,000 meters) villages cultivate more farmland (z = -5.387, P ≤ 0.001), a greater diversity of major crops (z = -5.760, P < 0.001), a higher percentage of traditional crops, and fewer cash crops (z = -2.430, P = 0.015) than those in lower elevation villages (< 2,500 meters). Villages with roads grow significantly more cash crops (z = -6.794, P ≤ 0.001). Both lower villages and villages with roads travel farther to access common property resources. Historical analyses indicate agricultural intensification in valleys, an increase in houses, new crop introduction, hillside aforestation, cessation of hunting, glacial retreat, and timberline advance within the past century. We suggest that Tibetan land use reveals trade-offs between high, remote villages and lower villages near roads. Higher villages offer abundant land and access to natural resources but short growing seasons and little market access; in contrast, lower villages have road and market access, an extended growing season, and modern technology, but limited access to land and many other natural resources.     

Diversity and use of palms in Zahamena, eastern Madagascar

Madagascar's palm flora is very diverse (171 species) and has a high degree of endemism (97%). Palm products make an important contribution to the household economy of many rural families, especially in the palm-rich eastern escarpments. Many palms are, however, threatened by overexploitation and habitat destruction. We investigated which palm species were found and used in three villages on the eastern escarpments of Madagascar. The importance local people accorded to each species was compared to the number of its uses, number of people using it, and other aspects of its use. From this comparison it was concluded that even if important palms are used for more purposes than less important palms, they owe their importance to one or two of their main uses. We also investigated if there were any patterns in the distribution of informants' knowledge and whether such patterns could be related to socio-economic factors. There was a positive relationship between knowledge about palms and personal wealth and a negative relationship between distance to the forest and amount of knowledge. The latter can be a sign of an ongoing knowledge erosion. Sustainable use of native palms should be encouraged as it may contribute positively to village economy and knowledge preservation, and may provide incentives for preservation of remaining forest tracts.     

Peatland forests are the least diverse tree communities documented in Amazonia,but contribute to high regional beta‐diversity

Western Amazonia is known to harbour some of Earth's most diverse forests, but previous floristic analyses have excluded peatland forests which are extensive in northern Peru and are among the most environmentally extreme ecosystems in the lowland tropics. Understanding patterns of tree species diversity in these ecosystems is important both for quantifying beta‐diversity in this region, and for understanding determinants of diversity more generally in tropical forests. Here we explore patterns of tree diversity and composition in two peatland forest types – palm swamps and peatland pole forests – using 26 forest plots distributed over a large area of northern Peru. We place our results in a regional context by making comparisons with three other major forest types: terra firme forests (29 plots), white‐sand forests (23 plots) and seasonally‐flooded forests (11 plots). Peatland forests had extremely low (within‐plot) alpha‐diversity compared with the other forest types that were sampled. In particular, peatland pole forests had the lowest levels of tree diversity yet recorded in Amazonia (20 species per 500 stems, Fisher's alpha 4.57). However, peatland pole forests and palm swamps were compositionally different from each other as well as from other forest types in the region. Few species appeared to be peatland endemics. Instead, peatland forests were largely characterised by a distinctive combination of generalist species and species previously thought to be specialists of other habitats, especially white‐sand forests. We suggest that the transient nature and extreme environmental conditions of Amazonian peatland ecosystems have shaped their current patterns of tree composition and diversity. Despite their low alpha‐diversity, the unique combination of species found in tree communities in Amazonian peatlands augment regional beta‐diversity. This contribution, alongside their extremely high carbon storage capacity and lack of protection at national level, strengthens their status as a conservation priority.     

Palm Uses in Northwestern South America: A Quantitative Review

A thorough review concerning palm uses in tropical rainforests of north-western South America was carried out to understand patterns of palm use throughout ecoregions (Amazonia, Andes, Chocó), countries (Colombia, Ecuador, Peru, Bolivia), and among the different human groups (indigenous, mestizos, afroamericans, colonos) that occur there. A total of 194 useful palm species, 2,395 different uses and 6,141 use-reports were recorded from 255 references. The Amazon had the highest palm use, whereas fewer, but similar uses were recorded for the Andes and Chocó. Ecuador was the most intensively studied country. Most palms were used for human food, utensils and tools, construction, and cultural purposes. Indigenous people knew more palm uses than mestizos, afroamericans and colonos. The use of palms was not random and the main uses were the same throughout the studied ecoregions and countries. Palms satisfy basic subsistence needs and have great importance in traditional cultures of rural indigenous and peasant populations in our study area. Arecaceae is probably the most important plant family in the Neotropics, in relation to use diversity and abundance.     

The impact of utilization of palm products on the population structure of the vegetable ivory palm (Hyphaene petersiana,arecaceae) in North-Central Namibia

Indigenous trees fulfil many subsistence and economic needs in north-central Namibia.Hyphaene petersiana provides a range of products which contribute to most aspects of people’s livelihoods. Of particular importance is its income-generating capacity through the use of palm leaves for basket production and the sale of liquor distilled from the fruits. This study investigates the population structure ofHyphaene petersiana in two areas of different human and livestock densities. Data were recorded for height class distribution, basal diameter of mature, stemmed individuals and sex ratios. These parameters of population structure indicate a reduction in the recruitment of mature palms and an increase in single-stemmed, vegetatively reproduced palm suckers of the smallest size class (0.5 m). This trend is more pronounced in the site with greater human and livestock population densities. It appears to be related to high recorded levels of browsing by livestock of juvenile, unstemmed palms, despite the unpalatability of palm leaves. This acts to prevent recruitment into larger size classes and increase the compensatory growth of palm suckers, the latter being enhanced due to reduced competition through the prior removal by grazing animals of grasses and other herbaceous species. Accompanying this heavy pressure on juvenile palms are destructive uses of mature, stemmed palms, including their felling for construction purposes and tapping for palm wine. With regional human population increase, exacerbated by a recent trend to privatise land and raise pressure on remaining communal resources, it is possible that these destructive uses of mature palms will increase to unsustainable levels. Concern is thus expressed in this study regarding the long-term viability ofHyphaene petersiana populatiops in this area.     

Addressing the threats to biodiversity from oil-palm agriculture

Oil-palm agriculture is the greatest immediate threat to biodiversity in Southeast Asia. Despite the efforts of environmentalists, oil palm continues to expand across the tropics. Those concerned about the impacts of oil palm on biodiversity must face some harsh social, economic, and ecological realities: (i) oil palm has been a very profitable crop; (ii) palm oil is used in so many products that simple, direct actions, such as boycotts, are unlikely to succeed; (iii) there is currently insufficient demand for certified sustainable palm oil and inadequate political clout from environmental groups in two of the biggest markets for palm oil—China and India—to slow the rate of forest conversion; and (iv) oil-palm agriculture has improved the lives of poor rural communities in Southeast Asia (although it has also disenfranchised some indigenous communities). To address the threats posed by oil-palm agriculture to biodiversity, environmentalists must change the behavior of the palm oil business through: (i) regulations to curb undesirable activities (e.g., a ban on converting forests to oil palm); (ii) financial incentives to promote desirable behavior (e.g., production of certified, sustainable oil palm); (iii) financial disincentives designed to discourage undesirable behavior (e.g., consumer pressure on major manufacturers and retailers to use palm oil that does not come from plantations created at the expense of forests); and (iv) the promotion of alternative, more biodiversity-friendly uses of forested land that might otherwise be converted to oil palm. There is no single best approach for dealing with the oil-palm crisis in Southeast Asia; a mixture of regulations, incentives, and disincentives targeted at all sectors of the oil-palm industry is necessary to protect the region’s rapidly disappearing forests.     

Palm Community Structure and Land Cover Changes in the San Juan Biological Corridor, Costa Rica

Biological corridors connect forest fragments, minimize the isolation of remaining habitats, and reduce the negative impact of fragmentation. Important studies in a corridor include documentation of land cover and the relationships between the plant community and land cover changes. In this study, density, species richness, and species diversity of palms of different life stages and growth forms were documented in forty 10 × 10 m census plots in the San Juan Biological Corridor (SJBC), Costa Rica. Changes in the percent cover of agricultural, partially forested, and forested lands from 1979 to 2001 were quantified based on existing land classifications. Associations between these palm community characteristics and the reduction in forest cover in 200-m and 1000-m annuli surrounding the census plots were investigated. These palm community characteristics were spatially interpolated to examine their distributions in SJBC. The community characteristics of palms of all growth forms varied among census plots. Forested lands in SJBC decreased from 88 percent to 26 percent during 1979–2001, while the percentage cover of agricultural and partially forested lands increased. The annual deforestation rate was 0.8 percent from 1979 to 1992, 4.3 percent from 1992 to 1997, and 7.5 percent from 1997 to 2001. Overall, palm community characteristics of small-canopy palms, dwarf palms, and cotyledonous seedlings had lower values with a lower percentage forest cover. The spatially interpolated palm community characteristics were consistently greatest within or adjacent to protected areas. This study demonstrates the complexity of the landscape and the effect of loss of adjacent forests on the palm community.     

Fate of epiphytes on phorophytes with different architectural characteristics along the perturbation gradient of Sabal mexicana forests in Veracruz,Mexico

Question: Vascular epiphytes and hemiepiphytes (E/HE) in neotropical forests account for a large fraction of plant richness, but little is known of how the interplay between phorophyte architectural characteristics and habitat perturbation affect communities of E/HE. Location: Sabal mexicana forests in a coastal area of Veracruz, Mexico. Methods: We compared communities of E/HE on phorophytes with different architectural characteristics – the palm S. mexicana and non‐palm phorophytes – in three environments: conserved sites, perturbed sites and small regenerated forest fragments. We combined traditional (abundance, species richness, similarity and complementarity indices) and more recent (phylogenetic diversity) metrics to describe the communities of E/HE. Results: Overall, we recorded 924 E/HE individuals (nine families, 16 genera and 21 species). The abundance and species richness of E/HE was higher on palms than on non‐palm phorophytes. Abundance‐based complementarities between phorophytes and sites were high. We detected clear changes in community structure of E/HE with habitat perturbation, but there were no effects on the phylogenetic diversity of the E/HE community. Palm phorophytes hosted a more phylogenetically diverse community of E/HE than did non‐palm phorophytes. Conclusions: Palm phorophytes are key elements supporting the conservation of resilient communities of E/HE in S. mexicana forest. Habitat fragmentation has a strong effect on the structure of the E/HE community in S. mexicana forests. Ferns are the group of epiphytes most severely affected by habitat perturbation, but we detected no significant effect on the phylogenetic diversity of the community.     

Residents’ attitudes toward three protected areas in southwestern Nepal

Understanding people’s beliefs and attitudes toward protected areas is a key factor in developing successful management plans to conserve those areas over the long-term. Yet, most of the emphasis in understanding people’s perceptions has been on the conflicts that exist between people and protected areas, such as loss of traditional extraction access or damage by wildlife to crops and livestock. This study addresses the need to explore people’s attitudes toward protected areas in a way that allows them to define and describe the values they hold toward the areas and the relevant issues and concepts. Three contrasting protected areas in the southwestern region of Nepal were chosen for this study to gain a broad representation of the values people hold toward different types of protected areas. Three themes emerged that describe the positive perceptions residents have: recreation/esthetics, environmental preservation, and economic benefits. Four themes emerged that describe the negative perceptions: negative economic impacts, belief that benefits are for the government or foreigners, fear of wildlife, and negative interactions with park guards. People’s perceptions are affected by different aspects of the areas, including the size of the area and people’s access to them, management objectives, history, and tourism. The diversity of these perceptions suggests that conservation strategies should recognize both positive and negative perceptions and work to foster and integrate diverse values in order to more accurately reflect the reality and complexity of people’s lives.     

Leaf litter depth as an important factor inhibiting seedling establishment of an exotic palm in tropical secondary forest patches

Intact tropical rainforests on continents and continental islands are considered to be relatively resistant to invasions by introduced plant species, but fragmentation and degradation may render them susceptible, especially to species from predominantly shade-tolerant families with centres of diversity in the tropics, such as palms. We investigated the seedling establishment patterns of the most common exotic palm species in Singapore’s secondary forest patches, the Macarthur palm (Ptychosperma macarthurii), in relation to landscape-level planting intensity, abiotic conditions, and recipient community composition. We first used conditional inference forests to narrow down the set of possible explanatory variables, followed by fitting generalised linear models with the forest patch and individual plots as random intercepts, to account for the nesting of plots within patches and overdispersion, respectively. The number of cultivated adults in the vicinity was not an important variable. Instead, leaf litter was the most important predictor of seedling density. Thick leaf litter in the disturbed and younger secondary forest matrix that surrounds old growth forest patches may therefore serve as a buffer against invasions, especially by small-seeded exotics. However, if adults of exotic species are allowed to establish unchecked, for example along forest trails that lead into the interior of the forested landscape, the seed rain may eventually reach old growth forest where leaf litter is typically thin. Further studies are required to determine if second-generation adults within invaded habitats contribute disproportionately more to propagule pressure than first-generation cultivated plants outside the invaded habitat.