Palm Iriartea Deltoidea Research Articles

Can the Use of a Specific Species Influence Habitat Conservation? Case Study of the Ethnobotany of the Palm Iriartea Deltoidea and Conservation in Northwestern Ecuador

This study explores the concept of conservation through plant use, looking at the palm Iriartea deltoidea (Arecaceae) in the rain forests of Ecuador. The study area is in the Mache-Chindul Ecological Reserve, one of the hotspots of biodiversity. Mestizos and Afro-Ecuadorians live in and around the reserve, and this paper looks at how these groups utilize the palm, mostly for construction, and how the palm’s importance relates to conservation. Particular attention here focuses on the concept of perceptions and actions in relation to protecting a valued resource. Since I. deltoidea is central for these people and intact forests provide the best habitat for regeneration and strong stem material, locals recognize the importance of sustainable collection. However, the concept of maintaining an intact ecosystem to protect this resource does not manifest itself in habitat conservation. Through tapping into the conservation cognizance that already exists, NGOs could devise strategies from the communities’ awareness.

Can the Use of a Specific Species Influence Habitat Conservation? Case Study of the Ethnobotany of the Palm Iriartea Deltoidea and Conservation in Northwestern Ecuador

This study explores the concept of conservation through plant use, looking at the palm Iriartea deltoidea (Arecaceae) in the rain forests of Ecuador. The study area is in the Mache-Chindul Ecological Reserve, one of the hotspots of biodiversity. Mestizos and Afro-Ecuadorians live in and around the reserve, and this paper looks at how these groups utilize the palm, mostly for construction, and how the palm’s importance relates to conservation. Particular attention here focuses on the concept of perceptions and actions in relation to protecting a valued resource. Since I. deltoidea is central for these people and intact forests provide the best habitat for regeneration and strong stem material, locals recognize the importance of sustainable collection. However, the concept of maintaining an intact ecosystem to protect this resource does not manifest itself in habitat conservation. Through tapping into the conservation cognizance that already exists, NGOs could devise strategies from the communities’ awareness.

Similar understorey structure in spite of edaphic and floristic dissimilarity in Amazonian forests

Forest structure determines light availability for understorey plants. The structure of lowland Amazonian forests is known to vary over long edaphic gradients, but whether more subtle edaphic variation also affects forest structure has not beenresolved. In western Amazonia, the majority of non-flooded forests grow on soils derived either from relatively fertile sediments of the Pebas Formation or from poorer sediments of the Nauta Formation. The objective of this study was to compare structure and light availability in the understorey of forests growing on these two geological formations. We measured canopy openness and tree stem densities in three size classes in northeastern Peru in a total of 275 study points in old-growth terra firme forests representing the two geological formations. We also documented variation in floristic composition (ferns, lycophytes and the palm Iriartea deltoidea) and used Landsat TM satellite image information to model the forest structural and floristic features over a larger area. The floristic compositions of forests on the two formations were clearly different, and this could also be modelled with the satellite imagery. In contrast, the field observations of forest structure gave only a weak indication that forests on the Nauta Formation might be denser than those on the Pebas Formation. The modelling of forest structural features with satellite imagery did not support this result. Our results indicate that the structure of forest understorey varies much less than floristic composition does over the studied edaphic difference.

MANEJO DE LA PALMA BARRIGONA O CHONTA (Iriartea deltoidea Ruiz & Pav.) EN EL PIEDEMONTE AMAZÓNICO COLOMBIANO Y PERSPECTIVAS PARA SU COSECHA SOSTENIBLE

The wood of the palm Iriartea deltoidea is an excellent material used for building, furniture and handicrafts in the Colombian Amazon, especially in the Amazon foothills where a small industry has developed around this species. We report the management practices, uses and commercial trends of this species in the municipality of Mocoa (Putumayo). We present data on population structure at three contrasting sites. The estimated demand of stems is ca. 750 per year, and the area necessary to supply them is 17-83 ha. Harvesting is carried out in natural forests or in pastures. The management practices are selective logging, sowing of seedlings and sparing of palms in pastures. Taking into account the natural condition of Mocoa, the abundance of the species, its growth rate and the current extraction system, productivity could grow if the followings activities were performed: enrichment of secondary forests, re-population of eroded areas, reduction of deforestation, and establishment of minimal harvest sizes based on height rather than diameter.

Palms do not undergo secondary stem lengthening: A response to Renninger and Phillips (American Journal of Botany 99: 607–613)

Woody stems that have completed some maturation of metaxylem elements should not be capable of further axial extension ("secondary stem lengthening"). However, this mechanism has been claimed by Renninger and Phillips (American Journal of Botany 99: 607-613) to be a feature of the palm Iriartea deltoidea. In response, we describe structural features of palm stems based on extensive known features of their anatomy and development. In addition to the inability of metaxylem vessels to extend after they are mature, fully differentiated fibers of the vascular bundle sheath, which would exist at the time of proposed stem elongation would not be capable of belated extension. "Vessel spirals" claimed by these authors to be capable of stretching to accommodate secondary stem lengthening does not refer to well-established features of the course of vascular bundles. The approach adopted by Renninger and Phillips simply measures stems of different sizes as an implied developmental series. Consequently, results do not take into account changes in the development of the palm stem as it ages. The existence of secondary stem lengthening in the palm Iriartea deltoidea, something never before observed in any tree, cannot occur because it would indeed disrupt mature metaxylem vessels and would also require the secondary extension of mature lignified fibers.

A comparison of the hydraulic efficiency of a palm species (Iriartea deltoidea) with other wood types

Palms are an important component of tropical ecosystems, living alongside dicotyledonous trees, even though they have a very different growth pattern and vascular system. As monocots, vessels in palms are located within vascular bundles and, without a vascular cambium that many dicotyledonous trees possess, palms cannot add additional vessels to their vascular system as they get older and taller. This means that hydraulic architecture in palms is more predetermined, which may require a highly efficient hydraulic system. This preset nature, along with the decoupling of hydraulic and mechanical functioning to different cell types, may allow palms to have a more efficient hydraulic system than dicotyledonous trees. Therefore, this study seeks to determine the efficiency of the hydraulic system in the palm Iriartea deltoidea (Ruiz & Pav.) and compare this efficiency with other tree forms. We measured cross-sectional areas of roots, stems and fronds as well as leaf areas of I. deltoidea saplings. Likewise, cross-sections were made and vessel diameters and frequencies measured. This allowed for the calculation of theoretical specific conductivity (K(S,calc)), theoretical leaf-specific conductivity (K(L,calc)), and vessel diameter and vessel number ratios between distal and proximal locations in the palms. Iriartea deltoidea palms were found to have the largest, least frequent vessels that diverged most from the square packing limit (maximum number of vessels that fit into a given area) compared with other major tree forms, and they therefore invested the least space and carbon into water transport structures. Likewise, conduits tapered by ∼1/3 between ranks (root, bole and petiole), which represents an efficient ratio with regard to the trade-offs between safety and efficiency of the conducting system. Conduits also exhibited a high conservation of the sum of the conduit radii cubed (Σr(3)) across ranks, thereby approximating Murray's law patterning. Therefore, our results indicate that the palm I. deltoidea has a very efficient hydraulic system in terms of maintaining a large conducting capacity with a minimal vascular investment. This efficiency may allow palms to compete well with dicotyledonous trees in tropical and subtropical climates but other developmental factors largely restrict palms from regions that experience prolonged freezing temperatures.

“Secondary stem lengthening” in the palm Iriartea deltoidea (Arecaceae) provides an efficient and novel method for height growth in a tree form

Although traditionally assumed that all height growth in trees occurs at apical meristems, sequential measurement of internode lengths in the palm Iriartea deltoidea suggested that stems were lengthening long after the differentiation of tissues and far below the apical meristem. This observation is difficult to reconcile with the fact that neither the water-conducting vessels nor the sugar-transporting sieve tube cells are capable of lengthening after differentiation. However, the vascular bundles in palms form a spiral within the stem and could theoretically lengthen if the spiral "straightened". We marked stretches of internodes on small and medium-sized palms and measured their lengths over 2 years. Additionally, we collected material from small palms with short internodes and large palms with long internodes and made cross sections to determine the angle of vascular bundles within stems. We found that stems lengthened (up to 12% over 2 years) below the apical meristem in small and medium-sized palms and that the spiral angle in vascular bundles of small palms was significantly larger than at the base of large palms indicating a straightening of the spiral. These results represent the first determination of "secondary lengthening" in tree stems as well as the most efficient method for height growth in terms of carbon investment. Likewise, elongation of stems allows palms to exhibit plasticity in height growth rates for more rapid growth when short-lived canopy gaps are present than they would have with apical growth alone.

The effects of plant pathogens on tree recruitment in the Western Amazon under a projected future climate: a dynamical systems analysis

Summary 1. Climate change predictions in the Amazon have largely focused on carbon–water relations, while the impacts of increased air temperature and reduced precipitation on host–pathogen relationships have not been extensively explored. These relationships are known to affect recruitment of many Amazonian plant species. 2. Host–pathogen relationships are well suited to a dynamical analysis of the effects of climate change due to the direct linkages between pathogen behaviour and abiotic factors such as temperature and rainfall. 3. Seedlings of the palm Iriartea deltoidea experience significant mortality due to infection by the fungus Diplodia mutila. This host–pathogen interaction was examined by combining a semi‐analytical model with field data illustrating the temperature sensitivity of D. mutila reproductive rates and I. deltoidea seedling mortality in response to infection. 4. The data–model combination shows that projected climatic shifts in rainfall and temperature for the Amazon region will tend to reduce recruitment by altering pathogen activity and reducing palm fecundity. The magnitude of the reduction is sensitive to the details of the epidemiology of the D. mutila–I. deltoidea host–pathogen system, and ranges from 10% to 56% under plausible scenarios. 5. Although considerable uncertainty remains, the proposed model provides a blueprint for research on one aspect of ecosystem change in future climate models. 6. Synthesis. The study illustrates the potential for ecosystem responses to climate change, which can be investigated through tractable models simple enough to assimilate into climate modelling frameworks. Particular environmental sensitivities in fungal dynamics are identified. The implications of combined plant physiological stress and enhanced pathogenic activity under future climate scenarios are highlighted as critical issues for projecting forest response.

Light converts endosymbiotic fungus to pathogen, influencing seedling survival and host tree recruitment

AbstractEndophytic fungi that asymptomatically colonize plants^1^ are diverse and abundant in tropical ecosystems^2^. These organisms can be weakly pathogenic^3^ and/or mutualistic, frequently enabling plants to adapt to extreme environments, alter competitive abilities of host individuals and improve host fitness under abiotic or biotic stresses^4,5,6^. Diplodia mutila is a symbiotic endophyte/plant pathogenic fungus infecting the palm Iriartea deltoidea^7^, which dominates many wet lowland Neotropical forests. The fungus is an asymptomatic endophyte in mature plants, and disease and mortality are expressed in some seedlings, while others remain disease free. Here we show that seedlings bearing the endophyte show enhanced resistance to insect herbivory. However, high light availability triggers pathogenicity of the fungus, while low light favors endosymbiotic development, constraining recruitment of endophyte-infested seedlings to the shaded understory by limiting survival of seedlings in direct light. These results provide evidence that patterns of plant abundance and the mechanisms maintaining tropical forest biodiversity are the result of a more complex interplay between abiotic and biotic environments than previously thought.

Eastern Tukanoan Names of the PalmIriartea Deltoidea: Evidence of Its Possible Preagricultural Use as a Starch Source

The Eastern Tukanoan of the Vaupés River region along the Colombian-Brazilian border have long used the palm Iriartea deltoidea as a durable building material. A recent study examining the linguistic roots of the local names of various palm species reveals that, in at least five languages of the Eastern Tukanoan, the contemporary name for Iriartea deltoidea suggests that it was also once a source of starch, a use not yet recorded for this species. Considering its demographic and structural characteristics, harvest of Iriartea deltoidea for starch would not be suitable for sedentary societies. We present a hypothesis that contemporary names for this palm are remnants of words from a time when the ancestors of the Eastern Tukanoan were hunter-gatherers and exploited this source of starch.

EASTERN TUKANOAN NAMES OF THE PALM IRIARTEA DELTOIDEA: EVIDENCE OF ITS POSSIBLE PREAGRICULTURAL USE AS A STARCH SOURCE

ABSTRACT The Eastern Tukanoan of the Vaupes River region along the Colombian-Brazilian border have long used the palm Iriartea deltoidea as a durable building material. A recent study examining the linguistic roots of the local names of various palm species reveals that, in at least five languages of the Eastern Tukanoan, the contemporary name for Iriartea deltoidea suggests that it was also once a source of starch, a use not yet recorded for this species. Considering its demographic and structural characteristics, harvest of Iriartea deltoidea for starch would not be suitable for sedentary societies. We present a hypothesis that contemporary names for this palm are remnants of words from a time when the ancestors of the Eastern Tukanoan were hunter-gatherers and exploited this source of starch.

Falling palm fronds structure Amazonian rainforest sapling communities

The senescence and loss of photosynthetic and support structures is a nearly universal aspect of tree life history, and can be a major source of disturbance in forest understoreys, but the ability of falling canopy debris in determining the stature and composition of understorey communities seems not to have been documented. In this study, we show that senescent fronds of the palm Iriartea deltoidea cause substantial disturbance in tropical forest sapling communities. This disturbance influences the species composition of the canopy and subcanopy by acting as an ecological filter, favouring sapling species with characteristics conducive to recovery after physical damage. The scale of this dominance suggests that falling I. deltoidea debris may be influencing sapling community structure and species composition in Amazonian rainforests over very large spatial scales.