Dermotoglyphics in the Bribri and Cabear Amerindians from Costa Rica]

Digital and palmar dermatoglyphic patterns were analysed for 286 male and female Bribri and Cabecar Amerindians of Chibcha ascendancy from four populations located in southeastern Costa Rica. There was no significant difference among Pacific and Atlantic Cabecar samples, with the exception of the bc and cd ridge count. However, the Bribri groups present differences for 22 features, though the largest differences are between Bribri and Cabecar Pacific populations. A comparison with other Latin-American indians evidence that dermatoglyphic patterns of Bribri and Cabecar tribes are within the expected range, but it is important to notice the high frequency of digital arcs and the low frequency of worls. The results are similar to those observed using other genetic markers in the same populations, and demonstrate the discriminable capacity of the dermatoglyphics to tribal level for taxonomic and evolutionary studies.     

Genetic variation of the Y chromosome in Chibcha-speaking Amerindians of Costa Rica and Panama

Genetic variation of the Y chromosome in five Chibchan tribes (Bribri, Cabecar, Guaymi, Huetar, and Teribe) of Costa Rica and Panama was analyzed using six microsatellite loci (DYS19, DYS389A, DYS389B, DYS390, DYS391, and DYS393), the Y-chromosome-specific alphoid system (alphah), the Y-chromosome Alu polymorphism (YAP), and a specific pre-Columbian transition (C-->T) (M3 marker) in the DYS 199 locus that defines the Q-M3 haplogroup. Thirty-nine haplotypes were found, resulting in a haplotype diversity of 0.937. The Huetar were the most diverse tribe, probably because of their high levels of interethnic admixture. A candidate founder Y-chromosome haplotype was identified (15.1% of Chibchan chromosomes), with the following constitution: YAP-, DYS199*T, alphah-II, DYS19*13, DYS389A*17, DYS389B*10, DYS390*24, DYS391*10, and DYS393*13. This haplotype is the same as the one described previously as one of the most frequent founder paternal lineages in native American populations. Analysis of molecular variance indicated that the between-population variation was smaller than the within-population variation, and the comparison with mtDNA restriction data showed no evidence of differential structuring between maternally and paternally inherited genes in the Chibchan populations. The mismatch-distribution approach indicated estimated coalescence times of the Y chromosomes of the Q-M3 haplogroup of 3,113 and 13,243 years before present; for the mtDNA-restriction haplotypes the estimated coalescence time was between 7,452 and 9,834 years before present. These results are compatible with the suggested time for the origin of the Chibchan group based on archeological, linguistic, and genetic evidence.     

Genetic variation of cassava (Manihot esculenta Crantz) cultivated by Chibchan Amerindians of Costa Rica

This study focuses on the genetic diversity of the cassava (Manihot esculenta Crantz) grown by the Chibchan Amerindians of Costa Rica. The authors collected cassava in various locations within two Amerindian Reserves: Talamanca, inhabited by Cabecares and Bribris, and Coto Brus, inhabited by Guaymi. Through the use of isozyme electrophoretic techniques we found variation for six out of nine systems analyzed, namely DIA, EST, IDH, MDH, PGI, and SKD. No variation was found in ADH, PGD, and PGM systems. We analyzed the distribution of variation within and between the reserves, and found most of the variation occurred within reserves (Gst = 0.1084). Only low levels of genetic differentiation were found between reserves (Nei’s genetic distance = 0.0088). The high levels of genetic variation within reserves that we found concur with results of previous studies on cassava grown by South American Amerindians and farmers. The role of the breeding system of cassava and the agricultural practices of Amerindians in the maintenance of high levels of genetic diversity are discussed.     

Holocene vegetation and water level history in two bogs of the Cordillera de Talamanca, Costa Rica

Pollen records of Holocene sediment cores from the Costa Rican Cordillera de Talamanca (La Chonta bog, 2310 m and La Trinidad bog, 2700 m) show the postglacial development of the montane oak forest zone from ca. 9500 to 1500 yr BP. During the early Holocene (ca. 9500–700 yr BP), alder vegetation covered the La Chonta and La Trinidad bogs and their adjacent hills. The upper forest line is inferred to be at 2800–3000 m elevation. A Podocarpus-Quercus forest characterised the middle Holocene (ca. 7000–4500 yr BP). The upper forest line is located at >3000 m reaching the present-day altitudinal distribution. A Quercus forest characterised the late Holocene (ca. 4500–1500 yr BP). Compared to modern conditions, the early Holocene has similar average temperatures, but the moisture level was probably higher. Pollen evidence for the late Holocene indicates drier environmental conditions than today. In order to improve the paleoecological interpretation, we described the local vegetation and used moss samples as pollen traps at both montane bogs along strong soil moisture gradients.The Netherlands Centre for Geo-ecological Research, ICG     

Species Diversity of Edible Plants Grown in Homegardens of Chibchan Amerindians from Costa Rica

We studied edible crop species diversity at homegardens of two Chibchan Amerindian Reserves in Costa Rica: Talamanca and Coto Brus. We visited six settlements at Talamanca and five at Coto Brus. We recorded the number of edible crop species growing homegardens; we found 46 edible plant species at Talamanca and 27 at Coto Brus. The mean number of species per homegarden ranged between 3.80 and 6.80 at Coto Brus and 4.50 and 8.63 at Talamanca. We identified species that were common, i.e., found in most households and all settlements, and species that were rare. We estimated diversity indexes for each settlement and each Reserve. Also, we compared crop species composition between both Reserves and among settlements within each Reserve, using the Jaccard coefficient of community similarity. Settlements from the same Reserve were grouped together, with the exception of Villa Palacios from the Coto Brus Reserve.     

Dung Beetle and Terrestrial Mammal Diversity in Forests, Indigenous Agroforestry Systems and Plantain Monocultures in Talamanca, Costa Rica

In order to explore the importance of indigenous agroforestry systems for biodiversity conservation, we compared the abundance, species richness and diversity of dung beetles and terrestrial mammals across a gradient of different land use types from agricultural monocultures (plantains) to agroforestry systems (cocoa and banana) and forests in the BriBri and Cabécar indigenous reserves in Talamanca, Costa Rica. A total of 132,460 dung beetles of 52 species and 913 tracks of 27 terrestrial mammal species were registered. Dung beetle species richness and diversity were greatest in the forests, intermediate in the agroforestry systems and lowest in the plantain monocultures, while dung beetle abundance was greatest in the plantain monocultures. The number of mammal tracks per plot was significantly higher in forests than in plantain monocultures, whereas mammal species richness was higher in forests than in either cocoa agroforestry systems or plantain monocultures. Species composition of both terrestrial mammals and dung beetles also varied across the different land use types. Our study indicates that indigenous cocoa and banana agroforestry systems maintain an intermediate level of biodiversity (which is less than that of the original forest but significantly greater than that of plantain monocultures) and provide suitable habitat for a number of forest-dependent species. Although the agroforestry systems appear to serve as favorable habitats for many terrestrial mammal species, their potential positive contribution to mammal conservation is being offset by heavy hunting pressure in the reserves. As in other agricultural landscapes, the conservation of biodiversity in Talamanca will depend not only on maintaining the existing forest patches and reducing the conversion of traditional agroforestry systems to monocultures, but also on reducing hunting pressure.     

Incorporating livelihoods in biodiversity conservation: a case study of cacao agroforestry systems in Talamanca,Costa Rica

Over the past two decades, various organizations have promoted cacao agroforestry systems as a tool for biodiversity conservation in the Bribri-Cabécar indigenous territories of Talamanca, Costa Rica. Despite these efforts, cacao production is declining and is being replaced by less diverse systems that have lower biodiversity value. Understanding the factors that influence household land use is essential in order to promote cacao agroforestry systems as a viable livelihood strategy. We incorporate elements of livelihoods analyses and socioeconomic data to examine cacao agroforestry systems as a livelihood strategy compared with other crops in Talamanca. Several factors help to explain the abandonment of cacao agroforestry systems and their conversion to other land uses. These factors include shocks and trends beyond the control of households such as crop disease and population growth and concentration, as well as structures and processes such as the shift from a subsistence to a cash-based economy, relative prices of cacao and other cash crops, and the availability of market and government support for agriculture. We argue that a livelihoods approach provides a useful framework to examine the decline of cacao agroforestry systems and generates insights on how to stem the rate of their conversion to less diverse land uses.     

Phytogeography of the bryophyte floras of oak forests and páramo of the Cordillera de Talamanca, Costa Rica

Aim Central America is a biogeographically interesting area because of its location between the rich and very different biota of North and South America. We aim to assess phytogeographical patterns in the bryophyte floras of oak forests and páramo of the Cordillera de Talamanca, Costa Rica. Location Tropical America, in particular the montane area of Cordillera de Talamanca, Costa Rica. Methods The analysis is based on a new critical inventory of the montane bryophyte flora of Cordillera de Talamanca. All species were assigned to phytogeographical elements on the basis of their currently known distribution. Absolute and percentage similarities were employed to evaluate floristic affinities. Results A total of 401 species [191 hepatics (liverworts), one hornwort, 209 mosses] are recorded; of these, 251 species (128 hepatics, one hornwort, 122 mosses) occur in oak forests. Ninety‐three per cent of all oak forest species are tropical in distribution, the remaining 7% are temperate (4%) and cosmopolitan (3%) species. The neotropical element includes almost 74% of the species, the wide tropical element (pantropical, amphi‐atlantic, amphi‐pacific) only 19%. A significant part of the neotropical species from oak forests are species with tropical Andean‐centred ranges (27%). As compared with bryophyte species, vascular plant genera in the study region are represented by fewer neotropical, more temperate and more amphi‐pacific taxa. Bryophyte floras of different microhabitats within the oak forest and epiphytic bryophyte floras on Quercus copeyensis in primary, early secondary and late secondary oak forest show a similar phytogeographical make‐up to the total oak forest bryophyte flora. Comparison of oak forest and páramo reveals a greater affinity of the páramo bryophyte flora to temperate regions and the great importance of the páramo element in páramo. Surprisingly, oak forests have more Central American endemics than páramo. Main conclusions (1) Providing first insights into the phytogeographical patterns of the bryophyte flora of oak forests and páramo, we are able to confirm general phytogeographical trends recorded from vascular plant genera of the study area although the latter were more rich in temperate taxa. (2) Andean‐centred species are a conspicuous element in the bryophyte flora of Cordillera de Talamanca, reflecting the close historical connection between the montane bryophyte floras of Costa Rica and South America. (3) High percentages of Central American endemics in the bryophyte flora of the oak forests suggest the importance of climatic changes associated with Pleistocene glaciations for allopatric speciation.     

Genetic admixture and population substructure in Guanacaste Costa Rica

The population of Costa Rica (CR) represents an admixture of major continental populations. An investigation of the CR population structure would provide an important foundation for mapping genetic variants underlying common diseases and traits. We conducted an analysis of 1,301 women from the Guanacaste region of CR using 27,904 single nucleotide polymorphisms (SNPs) genotyped on a custom Illumina InfiniumII iSelect chip. The program STRUCTURE was used to compare the CR Guanacaste sample with four continental reference samples, including HapMap Europeans (CEU), East Asians (JPT+CHB), West African Yoruba (YRI), as well as Native Americans (NA) from the Illumina iControl database. Our results show that the CR Guanacaste sample comprises a three-way admixture estimated to be 43% European, 38% Native American and 15% West African. An estimated 4% residual Asian ancestry may be within the error range. Results from principal components analysis reveal a correlation between genetic and geographic distance. The magnitude of linkage disequilibrium (LD) measured by the number of tagging SNPs required to cover the same region in the genome in the CR Guanacaste sample appeared to be weaker than that observed in CEU, JPT+CHB and NA reference samples but stronger than that of the HapMap YRI sample. Based on the clustering pattern observed in both STRUCTURE and principal components analysis, two subpopulations were identified that differ by approximately 20% in LD block size averaged over all LD blocks identified by Haploview. We also show in a simulated association study conducted within the two subpopulations, that the failure to account for population stratification (PS) could lead to a noticeable inflation in the false positive rate. However, we further demonstrate that existing PS adjustment approaches can reduce the inflation to an acceptable level for gene discovery.     

Perceptions of Trees Outside Forests in Cattle Pastures: Land Sharing Within the Central Volcanic Talamanca Biological Corridor,Costa Rica

Trees outside forests can play an important role in production and conservation and increase connectivity within agricultural landscapes. However, farmers’ perceptions of the trees and the values they place on them will determine the extent to which they will do so in the future. In a case study in Costa Rica, northwest of the Central Volcanic Talamanca Biological Corridor, we conducted 42 semi-structured interviews with farmers and other key informants. Results show that farmers maintain trees on their land and attribute to them diverse values (technical, economic, ecological, social, cultural, aesthetic, and heritage). Farmers reported limitations to the maintenance of trees (lack of financial capital, labour, land area, technical assistance, and adapted species). In addition to potentially unsustainable Payments for Environmental Services, there is scope for more collaborative approaches to conserving the trees built on existing farmer practices.     

The Effects of Cropping Systems on Avian Communities in Cacao and Banana Agro‐Forestry Systems of Talamanca,Costa Rica

Multispecies agro‐forestry is generally lauded for providing ecosystem services, especially in tropical environments. Avian communities contribute to services such as biodiversity and pest management. Characterizing and evaluating avian community composition in similar cropping systems will help optimize management for ecosystem services. We examined the relationship between cropping system vegetation and avian communities in four shaded agro‐forestry systems common to the Limón province of Costa Rica: abandoned and managed systems of cacao, cacao with banana, and banana. During two field seasons, we detected 2605 birds from 106 species and identified 2791 trees and shrubs from 62 morphospecies. We compared vegetation and avian species richness across systems with mixed‐effects linear models. Canopy, understory, and groundcover vegetation differed among agro‐forestry systems. More ground‐ and understory‐foraging forest species were detected in agro‐forestry systems lacking banana, whereas richness of agricultural generalist species was highest in systems with banana. Richness of understory‐ and ground‐foraging species correlated with understory tree species richness and leaf litter. Our results indicate that shaded cacao and banana systems can have similar canopy‐foraging species richness that includes both agricultural and woodland generalist species, but that interspersing banana with cacao can adversely influence understory forest bird community composition. Agro‐forests with diverse understory vegetation support more understory‐foraging bird species that have proven valuable in pest management. Abstract in Spanish is available at http://www.blackwell‐synergy.com/loi/btp .     

Temporal variation of phytoplankton in a small tropical crater lake, Costa Rica

The temporal variation in lake's phytoplankton is important to understand its general biodiversity. For tropical lakes, it has been hypothesized that they follow a similar pattern as temperate ones, on a much accelerated pace; nevertheless, few case studies have tried to elucidate this. Most studies in Costa Rica have used a monthly sampling scheme and failed in showing the expected changes. In this study, the phytoplankton of the small Barvas's crater lake was followed for more than three years, first with monthly and later with weekly samplings, that covered almost two years. Additional information on temperature and oxygen vertical profiles was obtained on a monthly basis, and surface temperature was measured during weekly samplings around noon. Results showed that in spite of its shallow condition (max. depth: 7m) and low surface temperature (11 to 19 degrees C), the lake stratifies at least for brief periods. The phytoplankton showed both, rapid change periods, and prolonged ones of relative stasis. The plankton composition fluctuated between three main phases, one characterized by the abundance of small sized desmids (Staurastrum paradoxum, Cosmarium asphaerosporum), a second phase dominated by equally small cryptomonads (Chryptochrysis minor, Chroomonas sp.) and a third phase dominated by the green alga Eutetramorus tetrasporus. Although data evidenced that monthly sampling could miss short term events, the temporal variation did not follow the typical dry and rainy seasons of the region, or any particular annual pattern. Year to year variation was high. As this small lake is located at the summit of Barva Volcano and receives the influence from both the Caribbean and the Pacific weather, seasonality at the lake is not clearly defined as in the rest of the country and short term variations in the local weather might have a stronger effect than broad seasonal trends. The occurrence of this short term changes in the phytoplankton of small tropical lakes in response to weather variations needs to be further explored in other lakes.     

Aristolochia translucida,a new species from Costa Rica

A new species from Costa Rica,Aristolochia translucida, is described and its relationships to other species detailed.     

Glaucoma in Costa Rica. Initial approaches

Glaucoma is the second most frequent cause of irreversible blindness worldwide. Genetic factors have been implicated in the development of the disease. So far six loci (GLC1A-GLC1F) and two genes (TIGR/MYOC and OPTN) are involved in the development of juvenile (JOAG) and adult onset or chronic primary open angle glaucoma (COAG), while two loci (GLC3A,GLC3B) and one gene (CYP1B1) are known for primary congenital glaucoma (PCG). Here we summarize the results of the first genetic studies of glaucoma in Costa Rica. Nine families: 1 with JOAG, 1 with PCG and 7 with COAG were screened for mutations at the known genes. A 10 bp duplication, 1546-1555dupTCATGCCACC, at the CYP1B1 gene, causes, in homozygous state, glaucoma in the consanguineous PCG family. This mutation has been found in different countries and generates an early stop codon that termitates protein synthesis 140 amino acids earlier than the normal allele. In exon 1 of the T1GR/MYOC the innocuous Arg76Lys variant was found in two of the COAG families. In the OPTN gene two variants in the coding region (Thr34Thr, Met 98Lys) and 7 intronic changes were found in other Costa Rican glaucoma patients. One of the COAG families was chosen for a genome scan with 379 microsatellite markers and linkage analysis. LOD scores "suggestive" of linkage were obtained for several chromosomal regions. Evidence indicates that hereditary glaucoma in Costa Rica is highly heterogeneous and that further studies in the country will probably disclose some up to now unknown genes responsible for the disease.     

Distribution, ecology, life history, genetic variation, and risk of extinction of nonhuman primates from Costa Rica

We examined the association between geographic distribution, ecological traits, life history, genetic diversity, and risk of extinction in nonhuman primate species from Costa Rica. All of the current nonhuman primate species from Costa Rica are included in the study; spider monkeys (Ateles geoffroyi), howling monkeys (Alouatta palliata), capuchins (Cebus capucinus), and squirrel monkeys (Saimiri oerstedii). Geographic distribution was characterized accessing existing databases. Data on ecology and life history traits were obtained through a literature review. Genetic diversity was characterized using isozyme electrophoresis. Risk of extinction was assessed from the literature. We found that species differed in all these traits. Using these data, we conducted a Pearson correlation between risk of extinction and ecological and life history traits, and genetic variation, for widely distributed species. We found a negative association between risk of extinction and population birth and growth rates; indicating that slower reproducing species had a greater risk of extinction. We found a positive association between genetic variation and risk of extinction; i.e., species showing higher genetic variation had a greater risk of extinction. The relevance of these traits for conservation efforts is discussed.     

Trace metals in coastal sediments from Costa Rica

Marine sediment samples from four coastal ecosystems in Costa Rica were taken between the years 2000-2002 and their iron, lead, copper and zinc concentrations were determined by the atomic absorption technique with flame or graphite furnace. In the Pacific coast, Culebra Bay (Papagayo Gulf), Gulf of Nicoya, and Golfito Bay (Dulce Gulf), were selected as representative sites, and Moín Bay, at the Caribbean coast. Mean metal concentrations for all ecosystems followed the same pattern: Fe > Zn > Cu > Pb. No temporal pattern was found for any metal. Iron and copper mean concentrations were higher in Golfito Bay (5.8% and 87 microg/g, respectively) and lower in Moín Bay (3.4% and 52 microg/g, respectively). Zinc mean concentration was also higher in Golfito Bay (96 microg/g), but lower in Culebra Bay (66 microg/g). Lead mean concentration was higher in Moín Bay (6.4 microg/g) and lower in Culebra Bay (3.0 microg/g). Lead highest concentrations occurred in the Caribbean and in Golfito Bay, and for the rest of the elements the maximum values were found in Golfito Bay. On the basis of data obtained in this work, Culebra Bay was considered a relatively unpolluted location; Golfito Bay was more contaminated, and Moín Bay and the Gulf of Nicoya showed an intermediate condition.