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Ensete superbum (Roxb.) Cheesman an important taxon in India is threatened in Maharashtra. It is sporadically distributed on high altitude slopes and rocky cliffs in the Western Ghats. It is an important medicinal and economic plant utilized by people living in rural areas, while the leaves are also utilized in urban areas. The leaves are harvested for commercial purposes. The effect of leaf harvest on natural population with respect to regeneration of new plantlets was evaluated. The results revealed that, non-scientific leaf harvesting resulted in significantly reduced flowering and fruiting, less number of new plantlets in the population, and population degradation. Therefore, leaf harvesting should be practiced in a controlled manner to maintain the population health of this highly potential species.

Abstract: Natural populations deliver a wide range of products that provide income for millions of people and need to be exploited sustainably. Large heterogeneity in individual performance within these exploited populations has the potential to improve population recovery after exploitation and thus help sustain yields over time. We explored the potential of using individual heterogeneity to design smarter harvest schemes, by sparing individuals that contribute most to future productivity and population growth, using the understorey palm Chamaedorea elegans as a model system. Leaves of this palm are an important non‐timber forest product and long‐term inter‐individual growth variability can be evaluated from internode lengths. We studied a population of 830 individuals, half of which was subjected to a 67% defoliation treatment for 3 years. We measured effects of defoliation on vital rates and leaf size—a trait that determines marketability. We constructed integral projection models in which vital rates depended on stem length, past growth rate and defoliation and evaluated transient population dynamics to quantify population development and leaf yield. We then simulated scenarios in which we spared individuals that were either most important for population growth or had leaves smaller than marketable size. Individuals varying in size or past growth rate responded similar to leaf harvesting in terms of growth and reproduction. By contrast, a reduction in survival chance was smaller in large individuals than in small ones. Simulations showed that harvest‐induced population decline was greatly reduced when sparing individuals from size and past growth classes that contributed most to population growth. Under this scenario, cumulative leaf harvest over 20 years was somewhat reduced, but long‐term leaf production was sustained. A threefold increase in leaf yield was generated when individuals with small leaves were spared. Synthesis and applications. This study demonstrates the potential to create smarter systems of palm leaf harvest by accounting for individual heterogeneity within exploited populations. Sparing individuals that contribute most to population growth ensured sustained leaf production over time. The concepts and methods presented here are generally applicable to exploited plant and animal species which exhibit considerable individual heterogeneity. [ABSTRACT FROM AUTHOR]

Ensete superbum (Roxb.) Cheesman an important taxon in India is threatened in Maharashtra. It is sporadically distributed on high altitude slopes and rocky cliffs in the Western Ghats. It is an important medicinal and economic plant utilized by people living in rural areas, while the leaves are also utilized in urban areas. The leaves are harvested for commercial purposes. The effect of leaf harvest on natural population with respect to regeneration of new plantlets was evaluated. The results revealed that, non-scientific leaf harvesting resulted in significantly reduced flowering and fruiting, less number of new plantlets in the population, and population degradation. Therefore, leaf harvesting should be practiced in a controlled manner to maintain the population health of this highly potential species. [ABSTRACT FROM AUTHOR]

Assessing the demographic effects of leaf area losses in perennial plants is important to determine population resilience to natural and anthropogenic disturbances. Yet, while impacts of defoliation on vital rates of adult plants have been well documented, consequences for seed dispersal and seedling recruitment have been barely explored., Here, we assessed the effects of defoliation on fruit production, fruit/seed size, seed dispersal and seedling recruitment in populations of Chamaedorea ernesti-augustii, a tropical rain forest, understorey palm from Mesoamerica, whose leaves are exploited as a highly valuable non-timber forest product ( NTFP)., Fruit size and seed production were quantified in mature palms that were subjected to 0% (control), 25%, 50%, 75% and 100% experimental removal of standing leaves, applied every 6 months over 2 years. Seed dispersal by birds and gravity, and seed predation by small vertebrates on the ground were also quantified. Rates of seedling recruitment were recorded in non-defoliated and 'sterile' populations (75% sustained defoliation and periodical removal of all produced fruits). Finally, a stochastic model was used to quantify the overall effect of defoliation on seedlings recruited from locally (i.e. dispersed by gravity) and immigrant produced seeds (i.e. dispersed by birds)., Increasing defoliation strongly reduced seed production. The probability of bird dispersal was positively correlated with fruit/seed size. Isolated (i.e. bird-dispersed) seeds endured lower predation rates than grouped (i.e. gravity-dispersed) ones. Modelling showed that seedling recruitment rate is severely reduced in highly defoliated populations due to a strong decline in the number of seedlings coming from local seed sources. Surrounding non-defoliated populations could partly compensate for this effect via seedlings coming from immigrant seeds., Synthesis. Chronic and intense defoliation negatively affects seed production and dispersal, which reduces the probability of seedling recruitment. Such effects may have a profound impact on the dynamics and genetic variability of populations, which should be taken into account when considering the effects of natural defoliation and sustainability of leaf-harvesting regimes. [ABSTRACT FROM AUTHOR]

1. Perennial plants often endure chronic loss of leaf area due to recurrent physical damage, herbivory and, for species used as non-timber forest products, due to leaf harvesting. However, little is known about functional and demographic resilience (extent and speed of recovery) of plants subjected to varying levels of chronic defoliation. 2. We used a dioecious, understorey palm ( Chamaedorea elegans) to evaluate temporal trajectories and rates of recovery of leaf functional traits and vital rates (survival, growth and reproduction) after being subjected to experimental chronic defoliation regimes. 3. Pristine populations of mature C. elegans, categorized by gender (male and female), were subjected to five defoliation levels (0%, 33%, 50%, 66% or 100% of newly produced leaves) every 6 months over a period of 3 years (1997-2000). To evaluate recovery from defoliation, surviving palms were monitored for 3 years after the cessation of the defoliation treatment (2000-2003). We recorded leaf functional traits (leaf persistence, leaf production rate, leaf size and leaf area) and annual rates of mortality, growth and reproduction. 4. Cumulative effects of chronic defoliation concomitantly reduced leaf traits, survival, growth and reproduction, and this effect was stronger in female than in male palms, independent of plant size. Recovery from defoliation was faster in males than in females, but proceeded gradually overall. Survival increased first, followed by growth, while reproductive traits showed the slowest recovery rate. Recovery was independent of plant size. Notably, 3 years after defoliation treatment, the standing leaf area and probability of reproduction had not recovered to pre-defoliation levels. Additionally, we found that the occurrence of a severe drought in the first year (2000) after defoliation ceased led to decreased survival, growth and reproduction and the ability of plants to recover from defoliation. 5. Synthesis. Chronic defoliation reduces fitness components of C. elegans palms differentially between genders. Recovery is gradual and is slower and less complete in females compared with males. The lower level of resilience to chronic defoliation shown by female plants may have profound consequences for the dynamics and genetic variability of populations of tropical understorey plants undergoing prolonged defoliation. Such effects may be aggravated by severe drought episodes that are expected to increase in frequency according to global climate change predictions. [ABSTRACT FROM AUTHOR]

Abstract: Leaves of the long-lived Dioon merolae have been harvested intensively for decades (possibly for centuries) for ceremonial purposes by Zoque and mestizo groups inhabiting the Central Depression of Chiapas, Mexico. Over a period of four years, we evaluated vital rates (stem growth, leaf production, reproductive performance, and survival) and projected population growth rates in three populations (250 plants each, divided into eight size classes: new germinants, seedlings, saplings (S1, S2), and adults, A1–A4) with different leaf harvesting histories: non-defoliated by humans for at least 55 years (or very old harvest), defoliated annually until 15 years ago (recovering from harvest), and defoliated annually for at least the past 25 years (currently being harvested intensely). Population structure was affected by leaf harvest history. Stem growth was negatively affected by the annual harvest of leaves in size classes from seedlings up to A4 (ANOVA, P <0.003); fewer leaves were produced by seedlings, saplings and adults at the annually harvested site (ANOVA, P <0.027). Survival was high at all sites across all size classes; in the annually harvested site, A4 plants showed a decrease in survival (one dead out of four plants). Sex ratio of adults that produced cones during the four years of study was 61% males to 39% females. At the non-defoliated site, adult classes A2 and A4 produced >80% of the cones; no cones were produced by the A3 and A4 adult size classes at the annually harvested site. Asymptotic estimates of population growth indicated growing populations (λ ≥1); the highest mean values of finite population growth rate were obtained in the non-harvested site (λ =1.0202). Elasticity analysis with population projection matrices indicated that stasis (L, 9–38%) was the component that most contributed to λ, followed by growth (G, 1.2–2.9%), and fecundity (F, 0.2–1.1%). We observed detrimental effects on several vital rates due to continued long-term defoliation, although population growth parameters do not currently suggest a decreased trend as a result of the annual harvest of leaves. The duration of this study of a very long-lived plant species suggests caution when setting levels and frequency of leaf harvest. The results help pinpoint practical recommendations that could be implemented in a sustainable management plan for this species, particularly to increase seed production in the annually harvested site, and recruitment of new germinants and seedlings at all sites. However, sound practices will need to consider the interests of involved stakeholders (landowners, pilgrims, conservation organizations and authorities) to effectively reduce anthropogenic pressure on this endangered species. [Copyright &y& Elsevier]

Harvesting of cowpea leaves for use as leaf vegetable has gained prominence in many parts of Africa and Asia. Little is known on effects of leaf harvesting on leaf and grain yields and profitability of cowpea-based cropping systems. This study sought to determine yields and profitability sole cowpea or cowpea-maize intercrop under different cowpea leaf harvesting initiation times. The study was conducted at Kenya National Dry land Research Center – Machakos using a Randomized Complete Block Design with cowpea grown as a monocrop or intercropped with maize. Leaf harvesting was initiated at 2, 3 or 4 weeks after cowpea emergence (WAE) and a control where no leaf harvesting was done. Initiating leaf harvesting at 3 and 4 WAE resulted in highest leaf and grain yields, respectively among leaf harvested cowpea. Overall, cowpea grain yields were highest in control treatment. Leaf vegetable and grain yields were lower in intercrop than in monocrop treatments. Maize yields in intercrop treatments were improved following harvesting of leaves of the companion cowpea. Initiating leaf harvesting at 3 and 4 WAE yielded highest returns in cowpea-maize intercrop and sole cowpea, respectively. Intercropping was on overall more profitable than sole cropping. [ABSTRACT FROM AUTHOR]

1. Rain forest understorey plants suffer leaf area losses due to natural causes or when leaves are harvested as non-timber forest products. The negative effects of defoliation on plant fitness can be exacerbated during periods with strong water shortage and high temperatures, typical during ENSO (El Niño Southern Oscillation) years in Mexico and Central America. At present, the isolated and combined demographic effects of ENSO events and repeated defoliation on tropical rain forest plants are poorly understood. 2. We studied the consequences of repeated defoliation and an ENSO event on vital rates (mortality, growth, and reproduction) of the dioecious understorey palm Chamaedorea elegans. From March 1997 to March 2000 (including the 1998 ENSO year), we subjected 814 mature individuals to one of five defoliation treatments (0–100% of newly produced leaves were removed twice a year), recording mortality, growth (leaf production) and reproduction (inflorescence and seed production) every 6 months. 3. Increasing defoliation strongly reduced reproduction but had smaller effects on growth and mortality. Among non-defoliated palms, the probability of mortality increased with light availability, likely due to drought stress during the dry season, but this was not the case for the defoliated plants, probably because leaf area removal lowered transpiration and increased the root mass-to-leaf area ratio. During the ENSO year, growth and inflorescence production were stimulated, but survivorship and seed production diminished significantly, independent of defoliation level. 4. Synthesis. Variation in light availability and the occurrence of severe droughts can strongly affect demographic behaviour of understorey plants such as C. elegans, significantly influencing the effects of defoliation. Thus, strong episodic disturbance events (such as ENSO, insect outbreaks, strong storms, fires and landslides) should be taken into account to adequately understand the mechanisms that determine the population dynamics of forest plants and the potential for sustainable utilization of non-timber forest products. [ABSTRACT FROM AUTHOR]

Assessment of the effects of stimulant trade on the future survival of Catha edulis trees was conducted in the West Usambara Mountains. A total of 65 plots of 0.1 ha each were established along two transects. All C. edulis trees in each plot were counted and recorded based on their health status. Of the 350 sampled trees, only 12% were healthy whereas 88% were either damaged or dead or dying. The number of C. edulis trees in the plots reflected a similar situation to trees outside the plots. Health distribution for diameter classes revealed that leafy harvesting had more impact on large trees as compared with small trees. About 93% of all healthy trees had diameter class less than 20 cm. While 86% of all damaged trees had diameter class above 20 cm, no dead trees with diameter class less than 20 cm were recorded. This indicated that most leaves of large old trees were preferred compared with those of small and young trees. However, due to scarcity of leaves from large trees, leaves from regenerated seedlings were also harvested. Thus, in the absence of conservation efforts, C. edulis faces danger of extinction. [ABSTRACT FROM AUTHOR]

Although cost-effective, phytoremediation is too expensive when considering the large-scale pollution. Relative to harvesting the whole plant, it is more practicable to remove and dispose of senescent and dead leaves after phytoremediation. The phytoremediation efficiency of Festuca arundinacea for Cd was evaluated in this study, because over about 7% of the land area in China was contaminated with Cd. The accumulation, redistribution, and extraction of Cd were evaluated in different leaves of F. arundinacea intercropped with N-fixing species at different densities (Cicer arietinum L). The results showed that coordinate and malposed intercropping systems increased the dry weight of the senescent and dead leaves of F. arundinacea by 30–41% and 103–168% compared to the monoculture system, respectively. More Cd was redistributed to the senescent and dead leaves of F. arundinacea under both intercropping systems. Occupying only 22–30% of the total leaf biomass, senescent and dead leaves accumulated 74–88% of leaf Cd under different cultivation conditions. Relative to the monoculture system, intercropping decreased the amount of time needed to reduce soil Cd by 44–53%. The biomass production and Cd accumulation of F. arundinacea were higher in the malposed intercropping system, and it had higher remediation efficiency than the coordinate intercropping system. This study demonstrated that intercropping, especially malposed intercropping of F. arundinacea and C. arietinum L., is a practicable technology for leaf harvesting phytoremediation. • F. arundinacea produced highest amount of dead leaves in the intercropping system. • Cd was translocated to senescent/dead leaves of F. arundinacea in all treatments. • Cd removal efficiency was highest in malposed intercropping system. • Intercropping system reduced the disposal cost of the harvested residue. [ABSTRACT FROM AUTHOR]

Based on literature analysis of 308 angiosperm species inventoried from a 50-hectare forest plot on Barro Colorado Island, Panama, 40 species were selected and 80 samples (two samples for every species; leaf + twig and stembark samples) were collected for investigation of their medicinallpharmaceutical potential. Extracts of these 80 samples were tested in bioassay systems to assess cancer chemoprevention (eight assays), antiplasmodial, cytotoxicity, and anti-HIV activities. Details of bioassay techniques are described. Of the 40 species, 12 (30%) showed activity in one or more of the 11 bioassay systems used. These active species are Bombacopsis (= Pachira) quinata, Calophyllum longifolium, Casearia commersoniana, Lozania pittieri, Maclura tinctoria, Mouriri myrtilloides, Olmedia aspera (= Trophis caucana), Pseudobombax septenatum, Spondias radlkoferi, Stylogyne standleyi, Turpinia occidentalis, and Vochysia ferruginea. Because literature data on thechemistry of Bombacopsis (= Pachira) quinata, Lozania pittieri, Mouriri myrtilloides, Olmedia aspera (=Trophis caucana), Pseudobombax septenatum, and Stylogyne standleyi, are lacking, and similar data on the other six species are deficient, further firactionation and isolation work on these active species potentially may yield novel, biologically active structures. This study demonstrates that a plot-based selection of plant species for evaluation of their potential medicinal/pharmaceutical value has merit in achieving such a goal, and should beused in a program on plant drug discovery. [ABSTRACT FROM AUTHOR]