The Ecological Economics of Harvesting Sharp-Pointed Rush (Juncus acutus) in the Kizilirmak Delta, Turkey

The sustainable harvest of aquatic vegetation is not accounted for in the national economy, in decision-making, and environmental policy in the Kizilirmak Delta, a Ramsar wetland of international importance and a major agricultural area on the Black Sea coast of Turkey. This paper describes the harvesting and marketing of sharp-pointed rush (Juncus acutus) using information obtained from interviews with villagers who were harvesting rush, wholesalers and retailers, government officials, and NGOs. The gross market value of the harvested rush amounts up to U.S. $494,000 annually in 1998 prices, of which U.S. $217,000 is retained by villagers. The economic contribution of the harvest and especially its livelihood for the villagers must be accounted for in projects and policy-making. Encouragement and continuity of the conditions of economic, social, and ecological sustainability of the harvest is essential for the conservation of the delta and its biodiversity.     

Toward sustainable use of Palm leaves by a rural community in Kwazulu-Natal, South Africa

There is increasing pressure from communities neighbouring protected areas in KwaZulu-Natal, South Africa, to harvest resources from these areas. For example,Hyphaene coriacea Geartn. (vegetable ivory palm) leaves are extensively used by Zulu people for commercial and subsistence craftwork. This study investigates the effect of varying leaf harvest intensities on leaf production ofHyphaene coriacea in the Greater St Lucia Wetland Park in KwaZulu-Natal, South Africa, and aims to provide some management guidelines for sustainable use. Replicate plots subjected to three different harvest intensities were established and numbers and lengths of unopened leaves were monitored over four years. Results suggest that a harvest intensity of one leaf stem^-1 year^-1 would be sustainable. This is equivalent to 34% of calculated annual production. The 650 ha harvest area is estimated to produce 191 750 leaves year^-1 (4793 bundles) which could be harvested sustainably. The effects of leaf harvest, even at maximum harvest rate, on leaf production over the four year study period appear negligible although there was a slight decline over time in leaf production of trees subjected to high harvest intensity. A slight increase in leaf production was observed at moderate levels of harvest intensity.     

Harvesting Effects and Population Ecology of the Buriti Palm (<Emphasis Type="Italic">Mauritia flexuosa</Emphasis> L. f., Arecaceae) in the Jalapão Region,Central Brazil<Superscript>1</Superscript>

Harvesting Effects and Population Ecology of Buriti Palm (Mauritia flexuosa L. f., Arecaceae) in the Jalapão Region, Central Brazil. Buriti palm is used for several purposes in Jalapão, Brazil, among which harvesting of young leaves has the greatest potential impact on palm populations. This work aimed to (i) assess buriti palm uses, (ii) identify experimentally the impacts of young-leaf harvesting on growth, survival, and leaf production of individuals, (iii) evaluate density and structure of buriti populations at different distances from a local harvester community, and (iv) quantify the fiber yield of young leaves. We conducted 21 interviews, sampled six buriti palm populations, and monitored 60 buriti individuals to evaluate the impacts of harvesting young leaves. The harvesting practices of artisans did not affect the survival, leaf production, or growth of buriti individuals. The buriti palm is abundant and has a “reverse J” population structure, indicating population regeneration. However, some signs of overexploitation were pointed out by local harvesters and observed in the field; therefore, we recommend management practices that would contribute to sustainability, such as harvesting young leaves from individuals with a large number of mature green leaves, and harvesting young leaves in sites far from the communities.     

Interactions among leaf toughness, chemistry, and harvesting by attine ants

Abstract. 1. Young and mature leaves of a tropical legume, Inga edulis var. minutula Schery, are strikingly different in secondary chemistry, especially condensed tannins, and leaf toughness.
2. Bioassays with the two different leaf types indicate that leaf cutter ants, Atta cephalotes (L.), always find mature leaves relatively more acceptable than young leaves when selection was based on chemical cues.
3. Since extracts of young leaves show greziter inhibition of fungal pectinases we suggest that leaf-cutter ants are capable of distinguishing which leaf types are most suitable for the growth of their symbiotic fungus.
4. However, mature leaves are 3 times tougher than young leaves and this prevents leaf-cutter ants from harvesting the more suitable mature leaves.
5. Consequently, bioassays which require cutting before leaf removal indicate that some colonies actually harvest more from the less suitable young leaves.
6. We suggest that the quality of a colony's habitat may indicate whether a colony will harvest more of the less suitable young leaves. Colonies which are harvesting from highly suitable host plants avoid the tropical legume I.edulis while those in poorer habitats accept I.edulis but, because of leaf toughness, mostly harvest the less suitable young leaves.     

Chamaedorea (xatÉ) in the Greater Maya Mountains and the chiquibul forest reserve, Belize: An economic assessment of a non-timber forest product

Of the twelve species ofChamaedorea palm recorded for Belize, three are of international economic value because their cut leaves (xaté) are traded in the floricultural industry. Traditionally, Belize has not harvested xaté, the industry being based in Mexico and Guatemala. However, a decline in wild xaté stocks in these countries means Guatemalan leaf harvesters now illegally harvest xaté in Belize. To assess the local abundance of the BelizeanChamaedorea resource, its economic value, and the extent to which it has been illegally harvested, 209 plots measuring 20 meters (m) by 20 m were established in the Greater Maya Mountains (GMM) in western Belize, which includes the Chiquibul Forest Reserve (CFR). We estimate that 37.8 million leaves with a value of U.S. 0.3 million to xateros have been extracted from the CFR. The standing export value is calculated as U.S.0.3 million to xateros have been extracted from the CFR. The standing export value is calculated as U.S. 1.8 million for the CFR and U.S. $5 million for the GMM.     

Effects of summer and winter harvesting on element phytoextraction efficiency of Salix and Populus clones planted on contaminated soil

The clones of fast-growing trees (FGTs) were investigated for phytoextraction of soil contaminated with risk elements (REs), especially Cd, Pb, and Zn. As a main experimental factor, the potential effect of biomass harvesting time was assessed. The field experiment with two Salix clones (S1 – (Salix schwerinii × Salix viminalis) × S. viminalis, S2 – S. × smithiana) and two Populus clones (P1 – Populus maximowiczii × Populus nigra, P2 – P. nigra) was established in April 2009. Shoots of all clones were first harvested in February 2012. After two further growing seasons, the first half of the trees was harvested in September 2013 before leaf fall (summer harvest) and the second half in February 2014 (winter harvest). Remediation factors (RFs) for all clones and all REs (except Pb for clone S1) were higher in the summer harvest. The highest annual RFs for Cd and for Zn (1.34 and 0.67%, respectively) were found for clone S2 and were significantly higher than other clones. Although no increased mortality of trees harvested in the summer was detected in the following season, the effect of summer harvesting on the phytoextraction potential of FGTs clones should be investigated in long-term studies.     

Population Dynamics of the Dioecious Amazonian Palm Mauritia flexuosa: Simulation Analysis of Sustainable Harvesting

The dioecious, tropical palm Mauritia flexuosa has high ecological and economic value, but currently some wild populations are harvested excessively, which is likely to increase. In this study, we investigated the population dynamics of this important palm, the effects of harvesting, and suggested sustainable harvesting regimes. Data were collected from populations in the Ecuadorian Amazon that were assumed to be stable. We used a matrix population model to calculate the density-independent asymptotic population growth rate (λ= 1.046) and to evaluate harvesting scenarios. Elasticity analysis showed that survival (particularly in the second and fifth size class) contributes more to the population growth rate, than growth and fecundity. To simulate a stable population at carrying capacity, density dependence was incorporated and applied to the seedling survival and growth parameters in the transition matrix. Harvesting scenarios were simulated with the density-dependent population models to predict sustainable harvesting regimes for the dioecious palm. We simulated the removal of only female palms and showed how both sexes are affected with harvest intensities between 15 and 75 percent and harvest intervals of 1–15 yr. By assuming a minimum female threshold, we demonstrated a continuum of sustainable harvesting schedules for various intensities and frequencies for 100 yr of harvest. Furthermore, by setting the population model's λ= 1.00, we found that a harvest of 22.5 percent on a 20 yr frequency for the M. flexuosa population in Ecuador is consistent with a sustainable, viable population over time.     

Hunting Bambi—evaluating the basis for selective harvesting of juveniles

Human harvesting is often a major mortality factor and, hence, an important proximate factor driving the population dynamics of large mammals. Several selective harvesting regimes focus on removing animals with low reproductive value, such as “antlered” harvests in North America and juvenile harvesting in many European countries. Despite its widespread use and assumed impact, the scientific basis of juvenile harvesting is scattered in the literature and not empirically well-documented. We give the first overview of demographic, evolutionary and practical management arguments for selective harvesting of juveniles. Furthermore, we empirically test two demographic arguments based on harvest statistics of Red Deer (Cervus elaphus) in seven European countries. P₁: Harvesting juveniles has little influence on harvest growth compared with harvesting adult females due to the lower reproductive value of juveniles than adult females; P₂: Harvesting of juveniles dampens variance in harvest due to lower and more variable natural survival rates of juveniles compared with adults. We found that harvesting juveniles has little effect on harvest growth rate, while harvesting adult females has a significant negative effect (consistent with P₁), but that increasing the proportion of juveniles in the harvest did not decrease the variability in harvest between years (P₂ not supported). Based on our empirical findings and overview of arguments, we discuss how the merits of juvenile harvesting may vary over time as populations move from a low density to a very high density state.     

Productivity and management of Phytelephas aequatorialis (Arecaceae) in Ecuador

Phytelephas aequatorialis is endemic to western Ecuador. Vegetable ivory (tagua, the hard endosperm) and leaves for thatch (cade) are harvested from the palm and commercialised. Export of vegetable ivory from Ecuador reached a value of 14 million US$ in 2011, making it the second most important product from native palms in the country. Vegetable ivory and leaves are harvested mainly from the wild, although the palm is occasionally cultivated. Most seeds harvested for vegetable ivory are collected from the ground. In times of high demand, however, some harvesters collect immature infructescences; these young seeds are of inferior quality and unsuitable for the fabrication of tagua discs for export. Premature harvest reduces the amount of fully mature, high‐quality seed leading to resource limitation for the processing industry that already is unable to satisfy international demand. Fruit production in lowland agroforestry systems strongly correlates to the level of exposure to light. The development of infructescences takes 3 years in the lowlands (≤93 m a.s.l.) and over 4 years on the Andean slopes at around 1400 m a.s.l. Data from 365 tagged individuals show that male palms produce significantly more leaves than female palms and palms growing in the shade produce fewer, but longer and higher quality leaves for thatch. Leaf harvest has little impact on leaf production, but substantially reduces fruit production. Natural regeneration of Phytelephas populations in pastures is negatively affected, rendering the survival of these populations problematic. Sustainable use and commercialization of the two partially exclusive and locally competing products tagua (vegetable ivory) and cade (leaves for thatch) must be carefully designed. Application of unsustainable practices in the harvest of seeds and leaves, population decline in pastures, and resource limitation in the processing industry represent the main challenges in the sustainable use of this valuable palm species in the future.     

Chinese chestnut production in the United States: Practice,problems, and possible solutions

There are fewer than 162 ha of commercial Chinese chestnut orchards in the United States, with approximately half of these in the Southeast. Large numbers of Chinese chestnut seedlings are planted annually in the United States for home and game food production; however, knowledge about chestnut propagation, fertilization, pests, harvest, storage and marketing is not adequate. There is little commercial marketing of U.S.-grown Chinese chestnuts through roadside markets and local farmers’ markets as the supply is low and unpredictable. However, we yearly import 4.5 mill kg of European chestnuts to satisfy the U.S. market. Successful chestnut orchards will require vegetatively propagated selections, intensive management, mechanical harvesting, and control of insect and disease pests.     

LEAF DISPLAY,CANOPY STRUCTURE,AND LIGHT INTERCEPTION OF TWO UNDERSTORY PALM SPECIES

The implications of leaf size, leaf display, and crown size for whole-plant light interception were investigated in Geonoma cuneata and Asterogyne martiana, two understory palm species native to Central American rain forests. Adults of A. martiana had longer leaves, more leaves per plant, and greater total leaf area than G. cuneata adults. Geometric measurements within whole crowns were used to calculate light interception efficiency, a leaf-based measure of the proportion of total incident light that is intercepted by a crown. Light interception efficiency was higher in adult G. cuneata than in adult A. martiana; seedlings of the two species did not differ significantly in light interception efficiency. Decreased efficiency of adult A. martiana crowns was largely due to an increased proportion of pendent leaves. Compared to G. cuneata, adults of A. martiana had greater light interception capacity (the product of light interception efficiency and total leaf area), but they also had higher biomass costs of light interception. Lower biomass costs of light interception in adult G. cuneata enable this species to exploit successfully the most deeply shaded microsites in the rain forest understory.     

Effect of repeated harvesting on the content of caffeic acid and seven species of caffeoylquinic acids in sweet potato leaves

The purpose of this study was to investigate the effect of repeated harvesting on the content of caffeic acid (CA) and seven species of caffeoylquinic acids (CQAs) in sweet potato leaves using a newly developed high-performance liquid chromatography method. Six cultivars and two breeding lines were used in this study. Leaves were collected at monthly intervals from 1st harvest (May) to 4th harvest (August) in 2011 and 2012. ANOVA analysis revealed that the contents of CQAs were significantly different among all cultivars and breeding lines, but no significant differences were found for CA. No annual variation was confirmed in CA and CQAs. Repeated harvest of sweet potato leaves affected the content of only 4-CQA and 5-CQA. Post-hoc comparisons using Tukey’s method indicated that the contents of 4-CQA and 5-CQA in sweet potato leaves harvested at first time were significantly higher compared to those at the other harvest times.     

The effect of ryegrass mosaic virus on the yield of perennial ryegrass swards

The influence of ryegrass mosaic virus (RMV) on yield of perennial ryegrass swards was examined under two harvesting frequencies and at two levels of nitrogen fertilizer, in a field trial planted with a clone of ryegrass, cv. S 321, using small plots established with proportions of healthy and infected plants. RMV reduced the height and the number of tillers of plants grown in pots and reduced the height also of plants in the field. The swards were planted in August and at a harvest 8 wk later RMV reduced the yield from 2–12 to 1–52 t dry matter (d.m.)/ha. In the first full harvest year, RMV caused only a small reduction in yield where no N fertilizer was applied and the application of a very small amount of fertilizer would have recouped the loss. On the other hand RMV severely restricted the increase in yield resulting from heavy dressings of the fertilizer. Thus where 400 kg N/ha was applied, RMV reduced the total annual yield from 18-6 to 13-8 t d.m./ha. The effect of the virus was especially great both in the Spring, the period of maximum herbage production, and when the level of fertilizer was high.     

Herbivory Rate of Leaf-Cutting Ants in a Tropical Moist Forest in Panama at the Population and Ecosystem Scales

Leaf-cutting ants are frequently characterized as the major herbivores in the Neotropics, but quantitative data to back up this assumption are scarce. In this study, the consumption and herbivory rates for the entire leaf-cutting ant ( Atta colombica , Formicidae) population in an old secondary forest on Barro Colorado Island (BCI) in Panama were determined over 15 mo (on average 49 colonies). The number of harvested leaf fragments was calculated from monthly refuse deposition rates of the colonies and the regression between refuse deposition and harvesting rates. The inclusion of fragment characteristics (proportion of leaf fragments in the harvest, average fragment weight, and area) allowed us to calculate consumption and herbivory rates at colony, population, and ecosystem levels. The A. colombica population harvested 13.2 tons of biomass/yr and 13.1 ha of leaf area/yr, and deposited 9.4 tons of refuse material/yr. Rates varied considerably among colonies. At the ecosystem level, i.e. , per forest area, herbivory rates were 132 kg biomass/ha/yr and 1310 m² foliage/ha/yr. For the area on BCI where A. colombica occurs (100 ha), this is equivalent to 2.1 percent of the foliage area in the forest or 1.7 percent of the annual leaf-area production. This value is considerably lower than previously published estimates of leaf-cutting ant herbivory rates in tropical forests.     

Palm Management in South America

We reviewed information on management of useful palms in South America. We documented management for 96 species, from incidental activities intended to increase populations of wild palms to the inclusion of palms in complex agroforestry systems. Two species, Bactris gasipaes and Parajubaea cocoides, are domesticated. Managed species are remarkably fewer than species used in the region, which suggests that harvesters often disregard the fate of the species they use. The best way of managing palms is to employ harvest methods that do not decimate the populations. Although a variety of harvesting techniques have been documented, overharvest is common, and mismanagement prevails – unnecessary felling of palms in order to harvest leaves or fruits is a widespread practice. Research should focus on assessing production in response to management practices, but eradicating the habit of destructive harvest is an obvious priority. Research on palm management must be combined with actions addressed to all stakeholders of the palm/humans system.     

Two new species of Geonoma sect. Taenianthera (Arecaceae) from the western Amazon

Geonoma atrovirens and G. supracostata (sect. Taenianthera ) (Arecaceae) from the western Amazon are described and illustrated. Both species are described on material hitherto included in the widespread G. macrostachys s.l., a species complex of understory palms represented in most parts of the Amazon region. Geonoma atrovirens resembles entire-leafed forms of Geonoma macrostachys var. macrostachys but differs form that taxon in having extremely narrow, bluish green leaves, and a different structure of its staminate flowers. Geonoma supracostata differs from all forms of G. macrostachys in the combination of an usually well developed aerial stem and moderately dissected leaves with the veins sharply raised alternately on the adaxial and the abaxial side of the lamina. A key to the species of Geonoma sect. Taenianthera in the western Amazon is provided.     

Site-Specific Trade-offs of Harvesting Cereal Residues as Biofuel Feedstocks in Dryland Annual Cropping Systems of the Pacific Northwest,USA

Cereal residues are considered an important feedstock for future biofuel production. Harvesting residues, however, could lead to serious soil degradation and impaired agroecosystem services. Our objective was to evaluate trade-offs of harvesting wheat and barley residues including impacts on soil erosion and quality, soil organic C (SOC), and nutrient removal. We used agricultural data from 369 geo-referenced points on the 37-ha Washington State University Cook Agronomy Farm combined with model simulations to develop straw harvest scenarios for conventional tillage (CT) and no-tillage (NT) and both 2- and 3-year crop rotations with sequences of wheat, barley, and peas. Site-specific estimates of ethanol production from 2- and 3-year rotation scenarios ranged from 681 to 1,541 L ha^?1 yr^?1, indicating that both crop rotation and site-specific targeting of residue harvest are important factors. Harvesting straw reduced residue C inputs by 46 % and resulted in levels below that required to maintain SOC under CT. This occurred as a function of both straw harvest and low residue producing crops in rotation. Harvesting straw under CT was predicted to reduce soil quality as Soil Conditioning Indices (SCIs) were negative throughout the field. In contrast, SCIs under NT were positive despite straw harvest. Replacement value of nutrients (N, P, K, S) removed in harvested straw averaged $14.54 Mg^?1 dry straw and ranged from $36.04 to $80.30 ha^?1, while straw harvesting costs averaged $34.25 Mg^?1, and the current (2014) market value of straw is $65 Mg^?1. We concluded that substantial trade-offs exist in harvesting straw for biofuel, that trade-offs should be evaluated on a site-specific basis, and that support practices such as crop rotation, reduced tillage, and site-specific nutrient management need to be considered if residue harvest is to be sustainable.     

Edge Effects and Seedling Bank Depletion: The Role Played by the Early Successional Palm Attalea oleifera (Arecaceae) in the Atlantic Forest

In this study, we examined the impacts of Attalea oleifera on the structure of seedling bank and discuss potential mechanisms of palm influence. Seed rain, seedling bank, and palm leaf fall were assessed beneath the canopy and in the vicinity of 16 adult palms across the edges of a large fragment (3500 ha) of the Atlantic forest. Moreover, we examined A. oleifera impacts on seed germination and seedling mortality by experimentally submitting seeds and seedlings to prolonged palm-leaf covering. As expected, seedling bank beneath the adults exhibited reduced abundance and species richness at local and habitat scale. Small to large seeds (3.1–30 mm) were underrepresented in the seed rain below adults palms, while experimental leaf covering drastically reduced both seed germination and seedling survivorship. A. oleifera leaf fall occurred over the whole year (3.6±2.7 leaves/individual/yr), which resulted in deep leaf litter mounds (10.7±9.2 cm). Finally, adult palm density (21.6±11.9 individuals/ha) correlated negatively with seedling density across Attalea clusters. Our results suggest that A. oleifera exerts negative effects on the seedling bank by reducing seedling abundance and richness as a consequence of two complementary mechanisms: impoverished and size-biased seed rain plus reduced seed germination and increased seedling mortality due to prolonged covering by fallen leaves.     

Effects of growth regulators on fruit abscission in oil palm, Elaeis guineensis

By delaying harvest of fruit bunches of the oil palm Elaeis guineensis Jacq., an increase in their oil content can be obtained, but this is accompanied by increased harvesting costs and lower oil quality, as the number of detached fruit increases. Treatment of ripening bunches with auxins, gibberellic acid, or ethephon retards fruit abscission, and harvest can be delayed by up to 5 days without increase in the number of detached fruit. Indications are that oil yield might increase by more than 5% during this period, without change in harvesting costs or oil quality.     

Potential Management of <Emphasis Type="Italic">Chamaedorea seifrizii</Emphasis> (Palmae), a Non-timber Forest Product from the Tropical Forest of Calakmul,Southeast Mexico<Superscript>1</Superscript>

Potential Management of Chamaedorea seifrizii (Palmae), a Non-timber Forest Product from the Tropical Forest of Calakmul, Southeast Mexico. Leaves and seeds of Chamaedorea (xate) palms are important non-timber forest products (NTFPs). In the Calakmul region (Yucatan Peninsula) of Mexico, several communities have sporadically collected and sold seeds of C. seifrizii since 1980. However, harvesting has intensified recently, raising concerns about overexploitation. To evaluate the economic potential of leaf and seed exploitation in the area, we collected information on abundance, population patterns, and leaf and seed stocks in Ejido Conhuas, a community within the Calakmul Biosphere Reserve (CBR). Then we combined these data with current market values and hypothetical management regimes obtained from the literature for leaves and seeds. Conducting a quantitative analysis of 43 0.1^ha plots with differences in forest and soil type, we assessed the abundance of C. seifrizzi in the area. We also conducted interviews to estimate the importance of xate in the local economy. We found C. seifrizii density to be highly variable, with a mean (±SE) of 295 (±35), with forest type being the most influential factor. Population structures differ between forest types, with healthy populations in medium and lower forest. We found a mean density of leaves of harvestable size of 3,750 (±380) leaves ha^-1, while seed production was 1.5 (±0.3) kg/ha^-1 of fresh seeds. Assuming sustainable harvest rates of 30–50% for leaves and 80% for seeds, one hectare of forest could generate USD 7.0–15.9/ha^-1. Considering the number of households (102) and 10% of the total area managed each year (5,700 ha), this harvest could generate a household income of USD 391–838 annually. At the moment, xate trade represents a minor component in the economy of the community, but given the area’s extensive forest (>57,000 ha), the resource abundance, and the low human population, we believe the NTFPs derived from C. seifrizii have a potentially great economic impact in the area.