The stands of Copernicia tectorum (Arecaceae) in the Caribbean lowlands of Colombia: a managed pioneer palm facing river dynamics Claudia Torres*, Gloria Galeano & Rodrigo Bernal Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Apartado 7495, Bogotá, Colombia; [email protected], [email protected], [email protected] * Correspondence Received 12-VI-2014. Corrected 10-XII-2014. Accepted 19-I-2015. Abstract: Copernicia tectorum is a palm that grows in large populations on seasonally flooded savannas in the Caribbean region of Colombia, where its stems and expanded leaves are used in construction, and its unexpand- ed leaves are used to make handicrafts. We studied abundance and population structure in 34 plots of 20×10m (0.68 ha) of three localities (Plato, Córdoba and Magangué) at the Mompox Depression, an inner delta formed by the confluence of four large rivers. We recorded growth and mortality of 164 palms of different size classes over 13 months, and additionally we estimated seedling and juvenile mortality in two 10x10m plots within the same sites. Data analysis using Kolgomorov-Smirnov (KS), Kruskal-Wallis and Mann-Whitney tests were made on Statgraphics Plus and SPSS. We related the structure and dynamics of the palm stands to flood intensity. Copernicia tectorum has the fastest leaf production rate recorded for any palm (19-23 leaves/year in subadults and adults), and a short life span of ca. 46 years. The abundance, density and high leaf production rate of this palm offer a great potential for the sustainable use of its unexpanded leaves (especially at Plato, where there are ca. 480ha of palm stands with 300-1 000 individuals/ha), as leaf harvest from subadult and adult individuals does not appear to affect population structure. The palm is a pioneer of the flood plain, and the palm stands at particular sites appear to wax and wane following sedimentation dynamics, in which the species plays in impor- tant role. Current population structure and the scarce recruitment of juveniles at the study site suggest that the population is waning in that site. Management actions should be taken to reestablish natural river dynamics at the lagoon complex where the palm grows. Appropriate management of palm stands may contribute to minimize any negative effects of river dynamics. Rev. Biol. Trop. 63 (2): 525-536. Epub 2015 June 01. Key words: leaf harvest impact, leaf production, Mompox Depression, NTFP, pioneer plants, population struc- ture, seasonally flooded savanna. Fibers obtained from wild palms play a in Northern Colombia, this species is the domi- significant role in Colombian handicraft pro- nant element in the vegetation. In these areas duction (Linares, Galeano, García, & Figueroa, the palm has a major ecological role, due both 2008). One of the most important fiber-pro- to its abundance and to the numerous interac- ducing palms in the Caribbean lowlands is the tions with other organisms-it harbors termites, sará palm, Copernicia tectorum (Kunth) Mart., wasps, ants, birds, and epiphytes, and its fruits which grows only in dry savannas in Northern are food for fish, birds, and mammals (Troth, Colombia and Venezuela, where it forms exten- 1987; Torres, 2013; pers. obs.). sive stands in areas that are subject to severe The sará palm also has a great importance drought during the dry season, and to perma- to local communities, as its leaves and stems are nent flooding during the rainy season (Troth, used in construction, and fiber obtained from 1987; Galeano, & Bernal, 2010). In some its unexpanded leaves is the base of a flourish- lagoon complexes at the Mompox Depression, ing handicraft activity of local importance. In Rev. Biol. Trop. (Int. J. Trop. Biol. ISSN-0034-7744) Vol. 63 (2): 525-536, June 2015 525 the municipalities of Magangué (department regimes at three localities in the Mompox of Bolívar) and Plato (department of Magda- Depression, in the Caribbean region of Colom- lena), along the Magdalena river, at least 200 bia. We also present data on the impact of river families are involved in this handicraft produc- floods on the populations, and describe a plau- tion (Linares et al., 2008). However, the ongoing sible scenario of changes in the palm stands in process of deforestation and lagoon desiccation the long run. for establishing crops and for cattle ranching has reduced the palm populations, causing a MATERIALS AND METHODS decrease of fiber availability and a greater pres- sure on the surviving palm stands (Linares et Study site: We studied populations of C. al., 2008; Torres, 2013). Sustainable manage- tectorum around Ciénaga Zárate, and Ciénaga ment of this species requires an understanding Cascaloa, a complex of lagoons in the flood- of the stands, their role in these savannas and lands of the lower Magdalena river, near the lagoon complexes, and the possible impact of towns of Plato and Magangué, in the depart- leaf harvest on populations. ments of Magdalena and Bolívar, in Northern Extraction of non-timber forest products Colombia. This area is part of the Mompox (NTFPs) has been the subject of a long debate Depression (Depresión Momposina), Colom- as to the scope and extent of the research that bia’s largest wetland area, considered as an is required to guarantee sustainability (Peters, inner delta formed by the confluence of four 1996; Wong, Thornber, & Baker, 2001; Tick- large rivers -Magdalena, Cauca, Cesar, and tin, 2004). There seems to be a consensus, San Jorge (Plazas, Falchetti, Van der Hammen, however, about the need of basic biological & Botero, 1988). This area is classified as trop- and ecological studies, as a starting point to ical dry forest in Holdridge’s life zone system plan sustainable management, even for those (Instituto Geográfico Agustín Codazzi, 1977), species that have been traditionally used. The with an average temperature of 28°C, and required basic information includes abundance, 1 250-1 500mm annual rainfall. Intense rains density, population structure, production rate fall during March-May and August-December, of the plant organ used, and the plant’s over- and there are severe droughts during June- all growth rate (Peters, 1996), as well as an July and December-February. Flood dynamics assessment of any other ecosystem services throughout the seasons determines a water flow involving the used species, and its role in the from the Magdalena river to the lagoons and ecosystem. A first sign of unsustainable harvest vice versa. Floods follow the rainfall regime of is evidenced in size class distribution (Peters, the river basin’s midlands and highlands, which 1996; Bernal, & Galeano, 2013). Although is mostly bimodal, with a peak from mid-April for many plants the ideal size class distribu- to early June, and a second, higher one, from tion has an inverted-J shape (many seedlings mid-August to December. As a result, there and a decreasing number of juveniles and is a first flood between May and July and a adults), other size class distribution curves are second one between October and December. found among species growing in open areas or However, flood frequency, duration and level among those subject to extreme environmental have changed in recent years, as a result of changes (Peters, 1996). Because of this, an road construction, lagoon dessication, and the assessment of harvest impact must be based illegal use of lagoons and shores (Ministerio on the study of both harvested and unharvested del Medio Ambiente [MMA], 2002). This is populations (Bernal, & Galeano, 2013). evidenced by the fact that the hydrological In this paper we used data on abundance, station at Plato recorded for the Magdalena density, and size class distribution and plant river in February 2010 a lower level of 4.2m, growth, to assess the state of populations of close to the lowest value ever recorded (4.0m Copernicia tectorum under various harvest in 1977), and well below the average for that 526 Rev. Biol. Trop. (Int. J. Trop. Biol. ISSN-0034-7744) Vol. 63 (2): 525-536, June 2015 Magangué and Córdoba, palm stands are small and Córdoba,palmstands are Magangué At harvestedforthatching. were occasionally expanded leaves harvest, although spear leaf site (CiénagaCuchillo)therewas no recordsof fifth at the Silencio); and Plazoleta, Machosolo, Four of thesesitesareharvested(Cardonal, occur (area>1ha),mostlyoncommonlands. palmpopulations wherethelargest at Plato, chosen Five sites were harvesters. owners and with thehelpof land identified Sites were ofharvestonthepalm populations. the effect to detect able to be 20years,inorder of atleast of use a history with chose sites We 1). (Table of flooding,andinharvestintensity the level stands, in of thepalm inthenature differed ties The threesamplinglocali duction takesplace. pro and handicraft is mostintensive harvest These aretheareaswhere Córdoba (Bolívar). ties: Plato(Magdalena)andMagangué 1987)(Fig.1). fire (Troth, to its resistance and droughtand of flooding extreme conditions to its adaptation in unusual bean lowlands(Galeano,&Bernal,2010).Itis grows onlyintheCarib this species Colombia seed. In one and have ripe, when black bright ers. Fruitsareovoidtoobovoid,ca.3cmlong, flow hermaphrodite bear small, and branches numerous They have leaves. the beyond project Inflorescencesareinterfoliarand their margins. along hooked spines bear that petioles long m rigid segmentsupto1mlong,with1.6 leavescomposedofnumerous circular palmate, The crownhas15-25 long floods(Throth1987). to whithstandthe considered asanadaptation roots atthebase,whichhavebeen