DEMOGRAPHY of Astrocaryum Malybo H.Karst
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Publicación de la Facultad del Medio Ambiente y Recursos Naturales - Proyecto Curricular de Ingeniería Forestal revistas.udistrital.edu.co/ojs/index.php/colfor/index ARTÍCULO DE INVESTIGACIÓN DEMOGRAPHY OF Astrocaryum malybo H.Karst. (ARECACEAE) IN COLOMBIA, RECOMMENDATIONS FOR ITS MANAGEMENT AND CONSERVATION Demografía de Astrocaryum malybo H.Karst. (ARECACEAE) en Colombia, recomendaciones para su manejo y conservación Néstor García1, Gloria Galeano† & Rodrigo Bernal2 García, N., Galeano, G. & Bernal, R. (2017) Demography of Astrocaryum malybo H.Karst. (Arecaceae) in Colom- bia, recommendations for its management and conservation. Colombia Forestal, 20(2), 107-117. Recepción: 14 de agosto 2016 Aprobación: 22 de mayo 2017 Abstract malybo is a key species for conservation of the dry The palm Astrocaryum malybo is an endangered forest relicts in the Caribbean lowlands of Colombia. species growing in forest remnants in the Caribbean Keywords: Arecaceae, handicraft, Integral Projec- lowlands of Colombia, where its spear leaves provi- tion Model, NTFP, plant fibers. de fiber for a flourishing artisanal activity. We studied the palm’s population structure and dynamics near Resumen the town of Chimichagua, Cesar, in order to provide La palma Astrocaryum malybo es una especie en ecological information required for its management peligro que crece en relictos de bosque en las tie- and conservation. We modeled population growth rras bajas del Caribe colombiano, donde sus cogo- and fiber production in the next 20 years under di- llos suministran fibra para una próspera actividad fferent management scenarios using Integral Projec- artesanal. Se estudiaron su estructura y dinámica tion Models. Although there was a low proportion of poblacional en Chimichagua, Cesar, con el fin de seedlings and population structure was variable, the suministrar información ecológica para su manejo y population would grow for the next 20 years, with conservación. Se modeló el crecimiento poblacio- an annual growth rate of 7.1%, yielding ca. 35 spear nal y la producción de fibra durante los próximos 20 leaves/ha/year for artisanal activity. Simulations of años bajo diferentes escenarios de manejo, usando the model show that the population is susceptible to modelos de Proyección Integral. Aunque se encon- alterations that affect the survival of individuals; re- tró una baja proporción de plántulas y variaciones moval of as few as 34 palms of any size per ha/year en la estructura poblacional, la población tenderá a would cause the population to decrease, and spear crecer en los próximo 20 años, con una tasa anual leaf production will decline accordingly. Converse- de 7.1 %, suministrando cerca de 35 cogollos/ha/ ly, any increase in seedling growth or survival would año para la actividad artesanal. La modelación de lead to population growth. If properly managed, A. escenarios muestra que la población es susceptible 1 Departamento de Biología, Facultad de Ciencias, Pontificia Universidad Javeriana. Bogotá, Colombia. [email protected]. Cor- responding author. 2 Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Apartado 7495. Bogotá, Colombia. [email protected] http://dx.doi.org/10.14483/udistrital.jour.colomb.for.2017.2.a01 Colombia Forestal • ISSN 0120-0739 • e-ISSN 2256-201X • Bogotá-Colombia • Vol. 20 No. 2 • pp. 107-117 [ 107 ] Demography of Astrocaryum malybo H.Karst. (Arecaceae) in Colombia, recommendations for its management and conservation GARCÍA, N., GALEANO, G. & BERNAL, R. a alteraciones que afecten la supervivencia de los llevaría a un crecimiento de la población. Si se ma- individuos; con la eliminación de solo 34 palmas de neja adecuadamente, A. malybo es una especie cla- cualquier tamaño por ha/año, la población tenderá ve para la conservación de los relictos de bosque a decrecer y como consecuencia la producción de seco en el Caribe colombiano. cogollos decaerá. En contraste, cualquier aumento Palabras clave: Arecaceae, artesanía, fibras vegeta- en la supervivencia o el crecimiento de las plántulas les, Modelo de Proyección Integral, PFNM. INTRODUCTION al., 2007; García et al., 2011). Landowners prefer to eradicate the palms, due to the potential harm in- Astrocaryum malybo, locally known as palma es- flicted by the long spines, and the purported anno- tera, is an acaulescent spiny palm endemic to the yances caused by intruding harvesters. Even in the warm lowlands of northern Colombia, where it for- forest fragments surviving along creeks, palms su- ms small populations in dry or wet forest relicts ffer damages from cattle, which wander freely and (Galeano & Bernal, 2010). These populations have tread on seedlings. Yet, these forest fragments are decreased more than 50% during the past deca- the only areas where palm populations regenerate des, due to forest fragmentation or total deforesta- (García, 2013). tion, for establishing crops or pastures. As a result, In order to provide ecological information re- this species is now categorized as Endangered (Ga- quired for management and conservation of A. leano & Bernal, 2005). malybo in this region, we studied its population In the area surrounding the Zapatosa lagoon structure and transient dynamics in forest frag- complex, in the departments of Cesar and Mag- ments near the town of Chimichagua. In particular, dalena, remnant populations of A. malybo are the we addressed the following questions: What is the base of a flourishing handicraft activity upon which population structure and density of A. malybo in many households rely (Barrera et al., 2007; García et these fragments? How is the demographic behavior al., 2011; García, 2013). This activity is based on the under these conditions? How would population harvest of leaflets from unexpanded leaves, which growth and fiber production behave in the next 20 provide a fiber used for weaving mats and other years under different management scenarios? products (Linares et al., 2008; García et al., 2011; Gar- cía, 2013). Because of its subterranean stem, access to the unexpanded leaves is easy, and harvesters MATERIALS AND METHODS do not cut down the palms, as is done with other fiber-producing Astrocaryum species (García et al., Study species 2013; García et al., 2015). Besides this, leaf harvest involves other actions aimed to reduce damage to Astrocaryum malybo is a solitary palm with under- the harvested leaves, and, as a result, local ma- ground stem, or rarely up to 3 m tall, covered with nagement is considered sustainable (García et al., black spines up to 10 cm long. An adult individual 2011; García, 2013). has 15-20 leaves up to 4.5-6 m long, densely ar- Although leaf harvest probably does affect the med with dark brown to black, flattened spines up development of individual palms to some extent, to 20 cm long. Flowers are arranged in an erect, overall impact is minimal, compared to the whole- branched inflorescence up 1.4 m long; fruits are sale devastation of populations resulting from forest yellowish when immature, becoming violet or al- clearing for agriculture or cattle ranching (Barrera et most black when ripe (Galeano & Bernal, 2010). The Colombia Forestal • ISSN 0120-0739 • e-ISSN 2256-201X • Bogotá-Colombia • Vol. 20 No. 2 • pp. 107-117 [ 108 ] Demography of Astrocaryum malybo H.Karst. (Arecaceae) in Colombia, recommendations for its management and conservation GARCÍA, N., GALEANO, G. & BERNAL, R. species is endemic to Colombia, where it grows in Study design and data collection wet to moderately dry lowland forests in the Mag- dalena River basin, and around the northern end of We characterized population structure of A. maly- the Andes, west to the northern Pacific Coast (Ga- bo in eight 20 x 50 m plots established in six secon- leano & Bernal, 2010). dary forest remnants near Chimichagua (table 1). The relics were selected with the help of artisans, Study area which are also involved in leaf harvest. We cen- sused all individuals in each plot, and recorded Chimichagua is located in the southern depart- for each the number of leaves and the number of ment of Cesar (9° 15’19.3 “N, 73° 48’ 51.9” W), main veins in the youngest leaf. Since individuals in an area classified as tropical dry forest, althou- of this species usually do not have an aerial stem, gh most of the former forest cover has now disa- we used the number of main veins as the state va- ppeared. Average temperature is 27°C and average riable related to size, as often used in acaulescent annual rainfall is 2448 mm; September and Octo- palms (Galeano et al., 2010). The main veins were ber are the rainiest months, with an average of 391 always counted on the right side of the youngest mm/month, while the driest season spans from De- expanded leaf. cember to March, with an average of 54 mm/mon- We studied population dynamics in a 1.5 ha fo- th (Ideam, 2015). rest remnant located on the banks of a creek in fin- Natural vegetation in the region has undergo- ca La Cabaña (9° 16’ 19.6” N, 73° 51’ 15.9” W), ne a severe transformation into cattle pastures or where we tagged and censused 361 individuals subsistence crops (Estupiñán-González et al., 2011). of A. malybo between July 2012 and July 2013 The former dry forest is now represented by sma- (195 seedlings, 64 juveniles and 102 adults). We ll strips of secondary vegetation along waterways, selected this forest remnant because it harbored and is dominated by trees as Spondias mombim the largest population of the species in the region. L. and the palms Attalea butyracea (Mutis ex L.f.) Thirty-seven adult palms at this site had evidence Wess.Boer, Elaeis oleifera (Kunth) Cortés and As- of leaf harvest. We marked the youngest expanded trocaryum malybo. These forest relicts are within leaf in each palm and counted the number of main private land and are subjected to permanent distur- veins on its right side; in the second census (July bance resulting from cattle, fires, or the extraction 2013), we measured annual leaf production.