Effects of Harvest on the Sustainability and Leaf Productivity of Populations of Two Palm Species in Maya Homegardens

Traditional management practices are usually thought to be sustainable. The Maya manage Sabal (Arecaceae) palms in homegardens, using their leaves for thatching. The sustainability of such production systems depends on the long-term persistence of palm populations, whereas resource availability also depends on the number of leaves on individual palms. We examined how leaf harvest affects Sabal yapa and S. mexicana population growth rates (λ) and leaf production, comparing traditional and alternative harvest regimes in terms of sustainability and productivity. Demographic, harvest and leaf production data were recorded for three years in two homegardens. We used general integral projection models linked to leaf-production models to describe population dynamics and productivity. Harvest had no effect on S. yapa’s vital rates or on λ, but it changed the growth rate of individuals of S. mexicana, with a negligible impact on λ. Homegardens affected λ values, reflecting the species’ ecological affinities. S. mexicana, introduced from mesic forests, required watering and shade; therefore, its population declined rapidly in the homegarden that lacked both water and shade. The λ of the xerophilic S. yapa was slightly larger without watering than with watering. Palms usually compensated for leaf extraction, causing the number of leaves harvested per individual to increase with harvest intensity. Nevertheless, traditional management is relatively mild, allowing standing leaves to accumulate but reducing the homegarden’s yield. Apparently, the Maya do not seek to maximize annual production but to ensure the availability of large numbers of leaves in homegardens. These leaves may then be used when the entire roof of a hut needs to be replaced every few years.     

Teratorhabditis palmarum n. sp. (Nemata: Rhabditidae): An Associate of Rhynchophorus palmarum and R. cruentatus

Teratorhabditis palmarum n. sp., an associate of the palm weevils Rhynchophorus palmarum and R. cruentatus is described. Teratorhabditis palmarum was isolated from newly emerged adults and cocoons of R. palmarum from red-ring diseased coconut palms, Cocos nucifera, in Trinidad and Ecuador, and from red-ring diseased oil palms, Elaeis guineensis, in Colombia. Teratorhabditis palmarum was also associated internally with newly emerged adults of R. cruentatus from mature transplanted cabbage palmettos, Sabal palmetto, in Florida. Dauer juveniles of T. palmarum infested the genital capsule and body cavity of newly emerged adult female and male palm weevils. Adult nematodes isolated from cocoons and dauer juveniles from newly emerged palm weevils were cuhurable on bacterial lawns on several solid media. Females of T. palmarum have a single anteriorly directed ovary; vulva at 93-96% of the body length; short, hemispherical spicate tail; three or four teeth in the metastom; cuticle with distinct transverse punctations that change abruptly at the level of the procorpus to indentations of alternating size and arrangement; and eggs with cuticular sculpturing. Males have a crenate, peloderan bursa with a 2 + 5 + 3 pattern of bursal rays (7 extend to the margin of bursa); spicules linear, completely fused at the distal tip and dorsally for 50% of the total spicule length.     

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.     

Molecular genetic analysis of two native desert palm genera,Washingtonia and Brahea,from the Baja California Peninsula and Guadalupe Island

The complex geological and ecological processes that have generated high levels of biodiversity and endemism in the Baja California Peninsula have been the subject of intensive study. However, relatively little is known about phylogeography of the iconic endemic palm species of this region. We therefore analyzed a total of 2,294 bp of chloroplast and 738 bp of nuclear sequence data in 169 samples of five native palm species from Baja California, Sonora and Guadalupe Island. We found that Washingtonia and Brahea palms had low levels of genetic diversity and were highly structured, with the majority of species and major geographic regions being characterized by distinct haplotypes. We also found strong support for currently recognized species in Washingtonia, but our results were less clear cut for Brahea due to haplotype sharing. Furthermore, patterns of population structure were broadly consistent with historical vicariant events such as the inundation of the Isthmus of La Paz, the formation of the Sea of Cortez, and the more recent colonization and isolation of Guadalupe Island's palms. Our findings contribute toward a growing appreciation of the complexity of plant responses to past geological changes and also provide valuable baseline genetic data on relict American palm species.     

Population status,habitat dependence,and reproductive ecology of Bahama Orioles: a critically endangered synanthropic species

ABSTRACT Recent elevation of critically endangered Bahama Orioles (Icterus northropi) to species status prompted us to evaluate their population status, habitat use, and breeding ecology. From surveys, we estimated that at least 141 to 254 individuals remain globally, with 90 to 162, 24 to 44, and 27 to 48 individuals remaining on North Andros Island, Mangrove Cay, and South Andros Island, The Bahamas, respectively. Orioles were observed nesting exclusively in anthropogenic habitat (residential and agricultural land), but home ranges also included nearby pine forest and coppice (dry broadleaf forest). Most nests (40 of 46, or 87%) were in nonnative coconut palm (Cocos nucifera), with native Sabal palmetto and Thrinax morrisii, and an introduced Brassaia actinophylla also used. Trees selected by orioles for nesting were significantly taller, less likely to have shrubs underneath, further from cover, and had more palm trees nearby than randomly selected palm trees. Three of eight nests with known contents were parasitized by Shiny Cowbirds (Molothrus bonariensis). Lethal yellowing disease recently devastated coconut palms and reduced the number of orioles on North Andros, but palms on Mangrove Cay and South Andros remain healthy. The juxtaposition of anthropogenic habitat to suitable native habitats may be more important than any single factor for Bahama Orioles, especially for breeding adults and fledged young. Conservation of coppice habitat, at high risk for agricultural and residential development, is crucial for survival of this critically endangered synanthropic species.     

Establishment growth of cabbage palm,sabal palmetto (arecaceae)

Cabbage palms (Sabal palmetto) go through an establishment phase during which the stem grows downward for a period of time before growing upward. We estimated the duration of this phase for cabbage palms growing in coastal forest in Florida using a matrix model approach. All data were collected over a 2-yr period (1993-1995) in coastal forest at Waccasassa∗∗∗ Bay, Florida. The minimum time projected by the model for a plant to develop an aboveground trunk was 14 yr. We estimate that the fastest growing 1, 10, and 50% of plants would develop an aboveground trunk in 33, 42, and 59 yr, respectively. The projected duration of the trunkless phase is surprisingly long but not unlike other palms with similar types of establishment growth. Our estimates are much longer than anecdotal estimates for cabbage palms grown under nursery conditions but are similar to anecdotal estimates for plants grown in field conditions. Management practices that remove cabbage palms with aboveground stems usually leave a population of palms without aboveground stems that serves as temporary reserve for relatively rapid recovery of the palm stand. This may foster the perception by many that cabbage palms are fast growing.     

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.     

Evaluation of the bromatological potential of seeds and fruits ofSabal Mexicana Mart. (Arecaceae)

This work presents bromatological analyses performed on seeds and fruits of Sabal mexicana Mart.; a comparison with data existent of other palms and some phytochemical data are presented. A discussion of the possible importance of some results obtained and the potential use of this palm is presented

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Evaluacion del potencial bromatologico de semillas y frutos de sabal mexicana, mart. (arecaceae)

Résumé  Este trabajo presenta análisis bromatolólogicos realizados en semillas y frutos de Salbal mexicana Mart. Los resultados se comparan con datos existentes para otras palmas y se presentan algunos datos fitoquimicos; ademús se discute acerca de la posible importancia de algunos de los resultados obtenidos y su uso potential

     

Fruit production of the Ungurahua Palm (Oenocarpus bataua subsp.Bataua, Arecaceae) in an Indigenous Managed Reserve

The ungurahua palm (Oenocarpus bataua subsp.bataua) is widely used throughout the Amazon Basin for its thatch, fibers, wood, and edible fruits. The fruits of this species are especially important to indigenous peoples and yield a high quality oil. This study examines the use of this species by the Siona people of the Ecuadorian Amazon in the Cuyabeno Faunistic Reserve. The reproductive phenology, fruit production, and relationship between vegetative characteristics and fruit production is explored here. Fruit production varies greatly from palm to palm with a range of approximately 500–7000 fruits biennially. This amounts to approximately 700 kg/ha every two years. Height, diameter breast height (dbh), and number of leaves on an individual are poor predictors of tree productivity. Reproductive histories of individual palms are examined. The economic potential of this species and the implications of overharvesting are discussed.     

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.     

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.     

Remains of palms (Palmae) at archaeological sites in the New World: A review

A review of palm remains recorded at archaeological sites throughout the New World is presented. Remains have been found at 130 sites from the southern United States to southern Uruguay. They are of four kinds: carbonized or dry endocarps or seeds, phytoliths, pollen, and implements. Twenty-nine genera and at least 50 species of palms (i.e., about 9% of all American species) have been recorded. The oldest record dates back to 14,700b.p. for carbonized endocarp fragments of an unidentified palm in Rondônia, Brazil. The use of palms, as recorded from remains, was particularly widespread after 9000b.p. The predominant remains are endocarps ofAcrocomia, Attalea s.l.,Astrocaryum, Bactris, Syagrus, Elaeis, andOenocarpus, all of which are important sources of edible oils or edible fruits and are still widely used by aboriginal peoples. The review supports the hypothesis that human groups have played an important role in the dispersal of some palm species in the neotropics. Humanaided dispersal ofAcrocomia aculeata from South America into Central America, and ofOenocarpus bataua from northwestern Amazonia to other areas, is postulated. Archaeological remains support the hypothesis that pejibaye (Bactris gasipaes) was domesticated in the inter-Andean valleys or on the adjacent Pacific lowlands of Colombia and later introduced into the Amazon Basin.     

Modeling Disease Vector Occurrence when Detection Is Imperfect: Infestation of Amazonian Palm Trees by Triatomine Bugs at Three Spatial Scales

Background

Failure to detect a disease agent or vector where it actually occurs constitutes a serious drawback in epidemiology. In the pervasive situation where no sampling technique is perfect, the explicit analytical treatment of detection failure becomes a key step in the estimation of epidemiological parameters. We illustrate this approach with a study of Attalea palm tree infestation by Rhodnius spp. (Triatominae), the most important vectors of Chagas disease (CD) in northern South America.

Methodology/Principal Findings

The probability of detecting triatomines in infested palms is estimated by repeatedly sampling each palm. This knowledge is used to derive an unbiased estimate of the biologically relevant probability of palm infestation. We combine maximum-likelihood analysis and information-theoretic model selection to test the relationships between environmental covariates and infestation of 298 Amazonian palm trees over three spatial scales: region within Amazonia, landscape, and individual palm. Palm infestation estimates are high (40–60%) across regions, and well above the observed infestation rate (24%). Detection probability is higher (∼0.55 on average) in the richest-soil region than elsewhere (∼0.08). Infestation estimates are similar in forest and rural areas, but lower in urban landscapes. Finally, individual palm covariates (accumulated organic matter and stem height) explain most of infestation rate variation.

Conclusions/Significance

Individual palm attributes appear as key drivers of infestation, suggesting that CD surveillance must incorporate local-scale knowledge and that peridomestic palm tree management might help lower transmission risk. Vector populations are probably denser in rich-soil sub-regions, where CD prevalence tends to be higher; this suggests a target for research on broad-scale risk mapping. Landscape-scale effects indicate that palm triatomine populations can endure deforestation in rural areas, but become rarer in heavily disturbed urban settings. Our methodological approach has wide application in infectious disease research; by improving eco-epidemiological parameter estimation, it can also significantly strengthen vector surveillance-control strategies.     

Evaluation of sap flow methods to determine water use by cultivated palms

Sustainable management of water resources allocated to palm crops requires reliable tools for measuring palm water use. Thermometric sap flow methods developed for woody dicot plants hold great potential for use in palms, but there have been few investigations to determine whether such methods can be used successfully in ‘woody’ monocots. Here, we evaluate two sap flow methods for measuring whole-plant water use by potted cocos palms (Syagrus romanzoffiana): the Heat Ratio Method (HRM) and the Compensation Heat Pulse Method (CHPM). Measurements of whole-plant water use from the HRM and the CHPM were compared to gravimetric measurements acquired from an electronic balance. Of the two methods, the HRM gave the most accurate results and it most precisely described patterns of transpiration with respect to environmental conditions and leaf morphology. Estimates of total daily water use from the HRM and the balance were highly correlated (R² = 0.92; P < 0.0001) and very near to a 1:1 relationship—an excellent result given the potential for error associated with each method. As expected, the CHPM was seriously limited at low flow rates, but it agreed well with the HRM at higher flow rates (heat pulse velocity >4 cm h⁻¹). Anatomical investigations revealed that vascular bundles in measured palm fronds were evenly distributed and the distance between bundles was comparable in scale to the diameter of probes of HRM sensors, and most likely an order of magnitude smaller than the probable zone of thermal influence for HRM measurements. This contention was supported by results of mathematical modeling suggesting that HRM heat pulse velocities in palm-like sapwood remain largely unaffected by increases in heterogeneity caused by larger xylem vessels and wider interstitial tissues. Although wounding models for heat pulse sap flow methods have not historically catered for the effects of discrete vascular bundles, they are sufficiently approximate given our empirical validations, and we conclude that palm sapwood is thermally homogenous enough for the HRM and the CHPM to be used without modification. Overall, we present strong evidence that heat pulse methods such as the HRM and the CHPM can be used successfully in woody monocots. Finally, we note that the CHPM is likely to perform better in cases of very high flow rates, while the HRM provides more comprehensive monitoring of the usual range of flow rates including at night, early morning and during water deficit.     

The legacy of human use in Amazonian palm communities along environmental and accessibility gradients

Aim

Palms are iconic and dominant elements of neotropical forests. In the Amazon region, palms have been used and managed by humans for food, material, medicine and other purposes for millennia. It is, however, debated to what extent the structure of modern palm communities reflects long-term human modification. Here, we investigate the complex interplay of ecological and societal factors that influence the distributions of both human-used and non-used palms in western Amazonia.

Location

Amazonia.

Time period

Present.

Major taxa studied

Palms (Arecaceae).

Methods

We used Bayesian hierarchical joint species distribution models to predict the distributions and environmental niche dimensions of 78 western Amazonian species, and to explore their relationships with their diversity of human uses and with specific uses (food, construction and medicine). The models were parameterized with a comprehensive set of field- and satellite-derived environmental predictors.

Results

Our results suggest that a combination of ecological and anthropogenic factors drive the present-day distributions of Amazonian palms. The modelled ecological niches of the species revealed use-related species-sorting along soil, climatic, accessibility and drainage gradients. We found peaks in the proportions of useful palms and their diversity of uses in fertile soils, close to rivers, and on floodplains. These are habitats favourable for human settlement, although they harbour naturally restricted palm species pools. We also found a negative correlation between predicted palm species richness and number of human uses across western Amazonia.

Main conclusions

Soil characteristics, accessibility, and species pool size all contribute to defining palm–human relationships. At the basin scale, the signature of human use on palm communities was predicted to be stronger in the species-poor south-west than in central-western Amazonia. Overall, we conclude that environmental conditions have influenced modern Amazonian palm distributions both directly and indirectly, by regulating human settlement patterns and natural resource use over extended time periods.     

Parrots consume sodium‐rich palms in the sodium‐deprived landscape of the Western Amazon Basin

Herbivorous animals face shortages of different minerals in different geographic areas. In the Amazon Basin, sodium is often limiting, driving herbivores to seek supplemental sources. In the lowlands of the western Amazon Basin, parrots commonly consume sodium‐rich soils at clay licks but lick use varies widely among species, and to date, parrots in the region have not been reported consuming other supplemental sodium sources. We document 11 species of psittacines consuming sodium‐rich leaves and trunks of Attalea butyracea palms growing on sodium‐rich soils in lowland Peru. Consumed palms had more sodium and less potassium than uneaten A. butyracea palms and other palm species in the area. Among A. butyracea palm parts, sodium and Na:K ratios were highest in trunks (consumed by parrots in 94% of the 387 foraging bouts recorded) and lowest in leaves (consumed in only 14% of foraging bouts). The low potassium and high Na:K ratio suggest that birds may be seeking not just any sodium sources, but those low in potassium, as potassium is known to exacerbate dietary sodium shortages. Use of the palms and species’ abundance in the study area were not correlated. Instead, parrot species that consumed palms the most were those that use relatively few traditional soil clay licks. This finding suggests that parrot species in the region have fundamental differences in preferred strategies for obtaining supplemental sodium and may help explain documented interspecific differences in geophagy.     

Trade in Palm Products in North-Western South America

More than 200 scientific publications and Internet sources dealing with trade in palm products in north-western South America are reviewed. We focus on value chains, trade volumes, prices, and recent developments for some of the most important raw materials derived from native palms. Trade in palm products takes place at local, regional, national, and international levels. For local communities and individual households palm products may play a key role as the most important or only source of cash income. Most of these palm products are inadequately or not at all captured in trade statistics at the local and regional economic levels. Only products such as vegetable ivory and palm heart are monitored statistically, mainly because they are exported. Most raw materials derived from palms are extracted from the wild, and mainly by destructive harvesting. Reduced availability and rising prices on local and regional markets reflect incipient resource depletion. Only in vegetable ivory more or less sustainable wild harvesting methods prevail. Palm heart is increasingly being harvested from orchards and non-sustainable exploitation of wild populations is loosing ground. The international market for native palm oils and pulp (esp. Euterpe oleracea or açaí) is currently served almost exclusively from Brazil. Due to low oil contents and high production costs palm oils are currently used mainly for cosmetics. Based on their content of protein, starch, tocols, and carotenoids palm fruits have high nutritional value and represent a considerable potential for the development of functional foods, food supplements and animal fodder. Palms could undoubtedly play a more important role in the socio-economic development of north-western South America. Sustainability and marketing potential of palm products are negatively affected by the low income obtained by primary producers which often represents no more than 0.01–3% of the retail value. Poor governance, insecurity of land tenure and unequal sharing of profits endanger a sustainable long-term development of these valuable resources.     

Multiple locus genome-wide association studies for important economic traits of oil palm

Palm oil has a balanced fatty acid composition and has no trans fat. As a result, its use in food has increased as food-labeling laws have changed to specify trans fat content. Increasing oil production is the main goal in oil palm breeding. Genetic mapping and genomic studies in palm trees are necessary to understand the genetic architecture of economic traits of importance for palm oil production. To help achieve this, we sampled 422 oil palms from MPOB (Malaysian Palm Oil Board)­Angola germplasm collection and measured 13 economic traits from these palms. Multi-locus genome-wide association studies (GWAS) were conducted using least absolute shrinkage and selection operator (LASSO) and genome-wide efficient mixed model analysis. We identified 19 quantitative trait loci (QTLs) for 8 traits. Of these, four Angola-specific QTLs associated with bunch components were detected on chromosomes 4, 8, and 11. These QTLs are potentially useful for introgression of desirable genes from the Angola palms to advanced breeding populations for improvement of bunch and oil yield traits. The majority of the QTLs were detected by LASSO-A, in which the p values of individual markers were calculated based on bootstrapped standard errors. Many of the detected QTLs are nearby known QTLs detected from linkage studies reported by other research groups. We also conducted genomic selection (GS) for the 13 traits and concluded that GS can be an effective tool for oil palm breeding. This is the first GWAS and GS study conducted on oil palm germplasm from Angola, and the results can be very useful in oil palm genetic studies and breeding.