RESUMO Nas florestas de terra firme não inundáveis da Amazônia, a composição florística e a ocorrência de espécies podem ser explicadas pela disponibilidade hídrica relacionada com a topografia. Dada a complexidade topográfica, a disponibilidade de água pode ser bastante variável e seus efeitos na resposta das plantas, difícil de documentar. Neste estudo avaliamos as respostas individuais de espécie de quatro grupos de plantas [pteridófitas (samambaias e licófitas), Melastomataceae, palmeiras (Arecaceae) e Zingiberales] às condições topográficas na região do médio Rio Juruá, no oeste da Amazônia brasileira. A área abrange duas formações geológicas (Içá e Solimões) com topografias contrastantes. Terraços fluviais também são encontrados ao longo dos rios principais. As condições topográficas foram medidas usando a altura acima da drenagem mais próxima (HAND), declividade e ordem de drenagem de Strahler, todas obtidas a partir de um modelo digital de elevação SRTM-DEM. Os dados foram analisados usando modelos lineares generalizados mistos e árvores de regressão. HAND foi a principal variável explicativa da composição florística para todos os grupos de plantas, exceto Melastomataceae, tendo maior efeito na formação Içá do que na Solimões. Ocorrências individuais de 57% das espécies foram explicadas por pelo menos uma das variáveis, sugerindo uma especialização marcada de habitat ao longo de gradientes topográficos. Para essas espécies, modelos usando variáveis derivadas do SRTM-DEM deram resultados semelhantes aos modelos usando apenas a topografia medida em campo, o que indicam que variáveis topográficas derivadas do SRTM-DEM podem ser usadas para prever variações locais na estrutura de comunidades de plantas em florestas tropicais.

ABSTRACT In Amazonian terra-firme non inundated forests, local floristic composition and species occurrence are explained by water availability as determined by topographic conditions. Topographic complexity can render these conditions quite variable across the landscape and the effects on plant ecological responses are difficult to document. We used a set of topographically defined hydrological metrics to evaluate community composition and single-species responses of four plant groups [pteridophytes (ferns and lycophytes), Melastomataceae, palms (Arecaceae) and Zingiberales] to topographic conditions in the middle Juruá River region, in western Brazilian Amazonia. The area spans two geological formations (Içá and Solimões) with contrasting topography. River terraces are also found along the main rivers in the area. Local topographic conditions were approximated by height above the nearest drainage (HAND), slope, and Strahler´s drainage order, all obtained from a SRTM digital elevation model (DEM). Data were analyzed using linear and generalized linear mixed models and regression trees. HAND was most successful in explaining floristic composition for all plant groups, except for Melastomataceae, and was more important in the hilly Içá formation than in the Solimões. Individual occurrences of 57% species were predicted by at least one of the topographic variables, suggesting a marked habitat specialization along topographic gradients. For these species, response models using SRTM-DEM-derived variables gave similar results than models using field-measured topography only. Our results suggest that topographical variables estimated from remote sensing can be used to predict local variation in the structure of plant communities in tropical forests.

RESUMEN Los bosques tropicales del Chocó biogeográfico presentan una de las mayores concentraciones de especies de plantas del mundo. Las palmas (Arecaceae) son una de las familias más importantes en las tierras bajas del Chocó, pero su ecología está poco estudiada. Investigamos la diversidad de comunidades de palmas en el Chocó y su relación con la precipitación en 48 transectos distribuidos en un gradiente de 2000-10 000 mm de precipitación. En cada transecto (5x500 m) se identificaron todas las especies de palmas y se contabilizaron todos los individuos. Registramos un total de 57 especies de palmas (promedio ± DS: 17 ± 8 por transecto) y 37 955 individuos (791 ± 446). Encontramos que la riqueza y abundancia de palmas están significativamente relacionadas con la precipitación (r2 = 0,86; P > 0,001). Se registró una fuerte correlación positiva entre la composición florística de las comunidades de palmas y la distancia geográfica (rM = 0,63; P = 0,001). La riqueza registrada es una de las más altas para el Neotrópico. La relación entre la precipitación, riqueza y abundancia de palmas por primera vez se documenta a escala regional en este punto caliente de biodiversidad.

ABSTRACT The tropical forests of the Chocó region support one of the largest concentrations of plant species in the world. Palms (Arecaceae) are one of the most important families in the Chocó lowlands, but their ecology remains little studied. We studied the diversity of palm communities in the Chocó and the relationship between diversity and precipitation in 48 transects distributed along a precipitation gradient covering 2000-10 000 mm annual rainfall. In each transect (5x500 m) all species of palms were identified, and all individuals were counted. We recorded a total of 57 species of palms (mean ± SD: 17 ± 8 in each transect) and we counted 37 955 individuals (791 ± 446 per transect). We found that palm richness and abundance were significantly related to precipitation (r2 = 0.86; P > 0.001). We also found that palm community composition was strongly correlated to the geographic distance between transects (rM = 0.63; P = 0.001). The recorded palm richness is one of the highest for the Neotropics. In addition, it is the first time that this relationship between precipitation, richness, and abundance of palms is documented at the regional level for the Chocó biodiversity hotspot.

Resumen En ecología una de las preguntas más importantes es: ¿cuáles son los factores ambientales que explican la alta diversidad de especies de plantas en los bosques tropicales? En este trabajo, se estudiaron las comunidades de palmas y su relación con los nutrientes del suelo en dos localidades del Chocó biogeográfico. Específicamente, se investigó: (1) cómo varían los nutrientes del suelo entre las dos localidades; (2) cuál es la relación entre los nutrientes del suelo y la composición florística de palmas; (3) cuáles son los nutrientes más importantes que explican la variación en la composición florística de las comunidades de palmas; y (4) cómo varía la abundancia de las especies dominantes de sotobosque y de dosel a lo largo del gradiente de concentración de los nutrientes más importantes. Se realizaron 20 transectos de 500 x 5 m (5 ha), en los cuales se identificaron y contaron todos los individuos de palmas en sus diferentes estadios de crecimiento. Las muestras de suelo se tomaron en cada uno de los transectos a los 0 , 250 y 500 m. Los cationes (Al, Ca, Mg, K, P) se extrajeron con la técnica Mehlich-III y las concentraciones se analizaron con espectrometría de emisión con plasma de acoplamiento inductivo (ICP-OES). La concentración de macronutrientes se relacionó con la composición florística mediante el test de Mantel, el test parcial de Mantel, regresiones lineales y escalamiento multidimensional no métrico (NMDS). Se encontraron 9 158 individuos y 33 especies de palmas en las 5 ha cubiertas por los transectos. La composición florística presentó una correlación positiva y significativa con los nutrientes del suelo (rM = 0.63-0.69) y con la distancia geográfica entre los transectos (rM = 0.71-0.75), mientras que las variables edáficas mostraron una alta correlación con la distancia geográfica (rM = 0.72). Asimismo, se encontró una débil relación significativa entre la fertilidad del suelo y la abundancia de palmas de sotobosque, pero ninguna con las palmas del dosel. Nuestros resultados demuestran que los suelos juegan un papel importante en la composición de las comunidades de palmas a escalas locales en la región del Chocó, y que los suelos más pobres y ricos en fósforo presentan la mayor diversidad de palmas.

Abstract One of the most important questions in ecology is: which are the environmental factors that explain the high plant diversity of tropical forests? We studied the floristic composition of palm communities and their relationship to soil nutrients in two localities of the Chocó region to understand (1) how soil nutrients vary between the two localities; (2) what is the relationship between soil nutrients and palm floristic composition; (3) what are the most important nutrients that explain the variation in floristic composition of palm communities; and (4) how does the abundance of the most exuberant understory and canopy palm species vary along the concentration gradient of the most important nutrients? We established 20 transects (5 x 500 m) and identified all palm individuals of all growth stages. Soil samples were taken at each transect at the beginning, middle, and end. Macronutrients (Al, Ca, Mg, K, P) were extracted with the Mehlich-III technique and their concentrations were analyzed by inductively coupled plasma emission spectrometry (ICP-OES). We used Mantel test, partial Mantel tests, linear regressions, and non-metric multidimensional scaling to determine if the concentration of nutrients was related to the floristic composition. We found a total of 9 158 individuals and 33 species of palms in the 5 ha covered by our transects. Floristic composition had a positive and significant correlation with soil nutrients (rM = 0.63-0.69) and with geographical distance between transects (rM= 0.71-0.75), whereas the soil nutrients were highly correlated with geographical distance (rM = 0.72). We also found a small, yet significant, relationship between soil fertility and the abundance of understory palms, but no relationship with canopy palms. Our results demonstrate for the first time that soils play an important role in the composition of palm communities at local scales in the Chocó region, and that infertile and phosphorus-rich soils have the highest palm diversity.

ABSTRACT Palms are most diverse in warm and humid regions near the equator. Though palms remain relatively well conserved, they are under increasing pressure from deforestation. Here, we analyze patterns of palm species richness relative to latitudinal gradient, sampling effort, and deforestation in the Amazon, and compare patterns of richness and floristic similarity among Amazonian sub-regions. We built a database of 17,310 records for 177 species. The areas with the greatest richness were in the western, central and northeastern Amazon, principally at latitudes 0-5ºS. Species richness and the number of records were highly correlated (R2=0.76, P<0.005). The highest rates of deforestation (>2000 km2) were found in the southern and eastern Amazon of Brazil, which coincide with low richness and gaps in records. Similarity analyzes resulted in two groups of sub-regions: the first included the Amazon s.s., the Andes and the Guiana, while the second included the Plateau and Gurupi. We conclude that the highest species richness is at low latitudes, and observed richness is affected by sampling effort and is vulnerable to deforestation. Therefore, areas with low species richness, especially areas with data deficiency, need to be further studied for a better understanding of their patterns of diversity and richness.

We studied palm communities, in particular species-richness and abundance, in the tropical rainforests in southeastern Peru in 54 transects (5×500m) covering an area of 13.5 hectares in flood plain, terra firme, terrace and premontane hills. We found 42 palm species in 18 genera in the transects. Terra firme forest had the highest species richness (38 species) followed by floodplain and premontane hills with 27 species and terrace forests with 26 species. The highest palm abundances were found in premontane hill forest which had 3243 palms per hectare and terra firme forest which had 2968 palms per hectare. The floodplain forests were intermediate in palm abundance with 2647 and the terrace forests had the lowest abundance with 1709 palms per hectare. Intermediate sized palms were the most common being represented by 18 species, while large palms were represented with 16 species. There were only eight species of small palms of which one was acaulescent. Only one species of liana palm was registered. Of the 42 species observed in the 54 transects, 20 were cespitose, 21 solitary and two had colonial growth. Seven species were found 40-320 km outside of their previously known range.

Estudiamos las comunidades de palmas de los bosques pluviales tropicales del sur de Perú, con especial énfasis en su riqueza de especies y abundancia, utilizando 54 transectas (5×500m), que cubrieron un área de 13.5 hectáreas en planicie inundable, terra firme, terraza y colinas premontanas. Encontramos 42 especies de palmas en las transectas. En el bosque de terra firme se encontró la mayor riqueza de especies (38 especies), seguido por la planicie inundable y las colinas premontanas con 27 especies y los bosques de terraza con 26 especies. Las mayores abundancias se encontraron en el bosque de colinas premontanas, con 3243 palmas por hectárea, y en el bosque de terra firme con 2968 palmas por hectárea. Los bosques de la planicie inundable presentaron una abundancia intermedia con 2647 palmas por hectárea y los bosques de terraza presentaron la menor abundancia con 1709. Las palmas de tamaño intermedio fueron las más comunes, estando representadas por 18 especies, mientras que las palmas grandes estuvieron representadas por 16 especies. Se encontraron solamente ocho especies de palmas pequeñas, una de las cuales era acaulescente. Sólo se registró una especie de palma trepadora. De las 42 especies observadas en las 54 transectas, 20 fueron cespitosas, 21 solitarias y dos presentaron crecimiento colonial. Siete especies se encontraron 40-320 km fuera del rango de distribución conocido previamente.

We studied the management of the fiber-producing chambira palm Astrocaryum chambira by indigenous people in the Colombian Amazon. Between 2009 and 2012, we visited four communities and two marketing centers, where we interviewed 12 people. In addition, we specifically observed A. chambira harvesting, processing, and commercialization; studied palm populations at five localities; measured leaf production rate; and integrated secondary data. At least 21 aboriginal groups in the Colombian Amazon use chambira fiber. The palm grows in association with human communities, and it has been widely used and managed in past agroforestry systems. The fiber is obtained from the unexpanded leaves of juvenile or adult palms, and harvesting is often unsustainable because of overharvesting acaulescent palms or of cutting down adult palms. This is leading to a depletion of palm population. Annual leaf production rate was 1.59-2.89 leaves/palm year−1, which is lower than that reported in other studies. Based in our results, we recommended a harvest of 1 leaf/palm year−1 in acaulescent palms, and 1-2 leaves/palm year−1 in stemmed palms. Chambira-derived products are mostly handicrafts for marketing, and their trade represents 40%-100% of artisan household cash income. Improving the management of chambira palms requires the introduction of non-destructive harvest techniques and a wider use of the palm in agroforestry systems. An analysis of traditional management practices and of the role of chambira among Amerindian people indicates that A. chambira was an incipient domesticate at the time of the European conquest.

A treatment of the family Juncaceae Juss. for the flora of Mexico is presented. The family includes two genera in this country: Juncus L. and Luzula DC. The first genus consists of 31 species and the second one of five. Keys for identification of the taxa, morphological descriptions, taxonomic notes, and information about the geographic distribution are provided, as well as some illustrations. One species is endemic: Juncus chiapasensis Balslev occurs only in the state of Chiapas. A second species, J. textilis Buchenau, is a local endemism, occurring in the state of Baja California as well as in the state of California in the United States of America.

Se presenta un tratamiento de la familia Juncaceae Juss. para la flora de México. La familia incluye dos géneros en dicho país: Juncus L. y Luzula DC. El primero comprende 31 especies y el segundo cinco. Se proporciona una clave para la identificación de los taxones, descripciones morfológicas, notas taxonómicas e información sobre la distribución geográfica, así como ilustraciones de algunas especies. Una especie es endémica: Juncus chiapasensis Balslev crece exclusivamente en el estado de Chiapas. Otra, J. textilis Buchenau, es un endemismo local que se encuentra en el estado de Baja California y en el estado de California en los Estados Unidos de América.

Se estudió la diversidad de comunidades de palmeras en la zona subandina y en tierras bajas adyacentes en 65 transectos (5 x 500 m), que abarcan 16.25 hectáreas de bosque distribuidas en un área de 700 x 125 km en el centro-norte de Bolivia. Un total de 38 especies de palmeras fueron encontradas en nuestros transectos. La comunidad de palmeras más diversa fue la del bosque de hoja perenne de terra firme (28 especies, 4.080 individuos por hectárea) seguida por los bosques premontanos < 800 m, (19 sp. y 2.873 ind./ha) y los bosques inundable de tierras bajas de hoja perenne (17 especies, 3.400 ind./ha). Los menos diversos fueron los bosques montanos por encima de 800 m (2.583 ind./ha en 16 especies) y los bosques caducifolios de tierras bajas, (1.207 ind./ha y sólo siete especies). De las 38 especies, 21 (55%) fueron solitarias, 15 (40%) fueron cespitosas y dos (5%) fueron coloniales. Las especies abundantes y dominantes, tanto en el dosel como en el sotobosque, son las mismas que en otros bosques de la Amazonia y aparecen en varias formaciones forestales en este estudio. La elevada riqueza de especies del bosque de hoja perenne de terra firme de tierras bajas se debe principalmente a un conjunto de especies raras que no aparecen en otras comunidades de palmeras. Las especies más abundantes fueron, en general, especies con distribuciones amplias y que son compartidas por varias de las comunidades de palmeras, lo que sugiere que son especies generalistas. Los bosques montanos tienen su propio conjunto de especies (tales como Dictyocaryum lamarckianum, Euterpe precatoria var. longevaginata y Geonoma undata) que los define, además de las especies comunes que comparten con otras formaciones forestales.

Palm community diversity and abundance was studied in the subandean zone and adjacent lowlands in 65 transects (5 x 500 m) covering 16.25 ha distributed over an area of 700 x 125 km in north-central Bolivia. A total of 38 palm species were found. The most diverse palm community was in lowland evergreen terra firme forest (28 palm species/4080 palm ind./ha, and seven growth forms), followed by the lower montane forest below 800 m elevation (19 palm species/ 2873 ind./ ha, and four growth forms) and lowland evergreen floodplain forests (17 palm species/3400 palms ind./ha, and five growth forms). The montane evergreen forests above 800 meters elevation (16 palm species/2583 palms ind./ha and three growth forms) and lowland seasonal evergreen and semideciduous forests (seven palm species/1207 palm ind./ha and five different growth forms) were the least diverse communities. Small palms were the most common growth form being represented by 18 (47%) species. Of the 38 palm species altogether, 21 (55%) were solitary, 15 (40%) were cespitose, and two (5%) were colonial. The abundant and dominant palm species, both in the canopy and in the understory, are the same as in other Amazonian forests and shared among several forest types in this study. The high species richness of the lowland evergreen terra firme forest is mostly due to a number of rare species that are lacking in other palm communities. The most abundant palm species were in general species with wide distributions shared among several palm communities suggesting that they are ecological generalists. The montane forests have their own set of palm species, such as Dictyocaryum lamarckianum, Euterpe precatoria var. longevaginata, and Geonoma undata, that separate them from other forest types.

This article presents an inventory of South American palms including 457 species and 50 genera. The distribution of palms within seven phytogeographical entities is analyzed. Factors which influence the evolution of palms in South America are discussed

Este artículo presenta un inventario de la flora de palmeras autóctonas de Suramérica, conformada por 457 especies y 50 géneros. Se analiza la distribución de este grupo vegetal en siete entidades fitogeográficas y se discuten los principales factores que influyen sobre la evolución de las palmeras en América del Sur.

The center of diversity of palms (Arecaceae) in tropical America is found in the Amazon basin and along the Panamanian isthmus.The greatest palm species richness has been reported for the Iquitos and Chocó areas. Many species of palms are used mainly for construction and due to their edible fruits. In addition, there are 104 palm species that are used for medicinal purposes in many regions of the Americas. Cocos nucifera and Oenocarpus bataua are the most commonly used species for medicinal purposes. The fruit is the most commonly used part of palms for medicinal purposes (57 species). The traditional and medicinal use of plants has deep roots in indigenous communities of Latin America. The significance of ethnomedicine for health care of local populations can not be ignored anymore because it plays a significant role in basic health care in developing countries. Interdisciplinary research in antropology, ethnobotany and ethnopharmacology helps gather information on ethnomedicine and design new drugs for modern medicine. American palms are sources of useful bioactive compounds against diabetes, prostate hyperplasia and leishmaniasis.

El centro de la diversidad de palmeras (Arecaceae) en América tropical se encuentra en la cuenca del Amazonas y a lo largo del istmo de Panamá. La mayor riqueza de especies de palmeras ha sido registrada para las áreas de Iquitos y de Chocó. Numerosas especies de palmeras son útiles, principalmente en la construcción y por sus frutos comestibles. Adicionalmente, 104 especies de palmeras neotropicales han sido reportadas con aplicaciones medicinales en muchas regiones de América. Cocos nucifera y Oenocarpus bataua, son las especies más utilizadas como medicinales. Los frutos, son la parte de la palmera de mayor uso con fines medicinales (57 especies). El uso tradicional y medicinal de plantas, tiene raíces profundas no sólo en comunidades indígenas de Latinoamérica, sino que es practicado en gran parte de la sociedad. El significado de la etnomedicina para la asistencia médica de las poblaciones locales no puede seguir siendo ignorado, porque la etnomedicina juega un papel significativo en la asistencia médica básica en los países en desarrollo. Investigaciones interdisciplinarias, antropológicas, etnobotánicas y etnofarmacológicas ayudan a brindar información sobre etnomedicina y diseñar nuevas drogas para la medicina moderna. Las palmeras americanas son fuentes de compuestos bioactivos útiles que pueden ser usados contra la diabetes, la hiperplasia de la próstata y la leishmaniasis entre otros.

Aphandra natalia (Balslev & Henderson) Barfod is a multipurpose palm that is exploited both commercially and for subsistence purposes. Its fibers are important in Peruvian and Ecuadorean broom industries and support many people economically. In Brazil, it is found in the western part of Acre, where it is the main source for a local broom market. Data from fieldwork in Peru (2007) suggests that the variation in gross profit per kilogram of fiber is considerable among the different segments in the broom industry. Harvesters and distributors earn negligible amounts of money whereas manufacturers reap of the major part of the earnings. Fiber extraction appears to be sustainable in Ecuador and in some parts of Peru, whereas in other parts of Peru unsustainable harvest occurs, involving felling of entire palm trees for the harvest of fibers. The same destructive extraction method is used in Brazil, where the palm is becoming rare in its natural distribution area.

La palmera de piasaba (piassava, piassaba) -Aphandra natalia (Balslev& Henderson) Barfod es una palma que se utiliza para muchos propósitos, tanto comerciales como para la subsistencia de pueblos rurales. Sus fibras son de importancia económica en industrias de escobas en Perú y Ecuador, las cuales sostienen económicamente a muchas personas. En Brasil, esta palma se encuentra en la parte oeste del estado de Acre, donde sus fibras constituyen el recurso principal para el mercado local de escobas. Información de campo originada en Perú en el año 2007, muestra que existe una importante variación en las ganancias económicas por kilo de fibra entre los diferentes sectores de la industria de escobas. Los que cosechan y distribuyen los productos obtienen ganancias muy reducidas, mientras que los productores de escobas son los que más ganan. La extracción de fibras parece ser sostenible en Ecuador y en algunas partes de Perú, mientras que en otras partes de Perú se tumban palmeras enteras para sacar la fibra, lo cual representa un método no sostenible. La misma forma destructiva de cosecha de las fibras existe en Brasil, lo cual ha traído como consecuencia que las poblaciones de la palma se encuentran muy disminuidas en su hábitat natural.

This paper describes the uses of 64 species of palms in 28 villages in Departamento de Loreto, Peru. There, the palms are of great use as food (Bactris gasipaes, Mauritia flexuosa, Euterpe precatoria, Oenocarpus bataua), for fiber production (Astrocaryum chambira, Aphandra natalia), for construction of houses (Euterpe precatoria, Iriartea deltoidea, Socratea exorrhiza), thatching (many species of Attalea, Lepidocaryum tenue) and for many medicinal purposes (Euterpe precatoria, Oenocarpus bataua).

Se presenta información etnobotánica sobre usos de 64 especies de palmas encontradas en 28 comunidades en el Departamento de Loreto, Perú. Las palmas tienen gran importancia como fuente de alimento (Bactris gasipaes, Mauritia flexuosa, Euterpe precatoria, Oenocarpus bataua), para la obtención de fibras (Astrocaryum chambira, Aphandra natalia), en la construcción de viviendas (Euterpe precatoria, Iriartea deltoidea, Socratea exorrhiza), para su techado (muchas especies de Attalea, Lepidocaryum tenue) y para usos medicinales (Euterpe precatoria, Oenocarpus bataua).