Endemic Melastomataceae of the Sierra Nevada de Santa Marta,Colombia

The 16 species of Melastomataceae restricted to the middle and upper slopes of the Sierra Nevada de Santa Marta, Colombia, are listed. Included are seven previously undescribed species:Graffenrieda santamartensis, Miconia insueta, Miconia oreogena, Miconia tricaudata, Huilaea kirkbridei, Kirkbridea tetramera, Kirkbridea pentamera. The newly described genusKirkbridea is placed in the tribe Miconieae.     

Pronophiline butterflies (Satyridae) of the Sierra Nevada de Santa Marta, Colombia

Abstract. The twenty-four species of Pronophilini known from the Sierra Nevada de Santa Marta, a small, isolated and very high north Colombian mountain range, are listed. The ecology of the tribe in northern South America, where these butterflies are exclusively montane, is described. The evolutionary relationships of the thirteen endemic species are analysed. Three new genera, three new species, and four new subspecies are described. Four new synonymies are established, the status of three taxa revised, six new combinations made, lished, the status of three taxa and one original combination re-instated.     

The savannization of moist forests in the Sierra Nevada de Santa Marta, Colombia

In the Rio Ranchería watershed of the Sierra Nevada de Santa Marta, between 500 and 1500 m, savanna vegetation is interspersed with moist forests. The savannas are composed of native savanna grasses like Aristida adscensionis L., Arundinella sp., Panicum olyroides Kunth, and Schyzachyrium microstachyum (Desv.) Roseng., Arrill & Izag and the African Melinis minutiflora P. Beauv. There is also Curatella americana L. and Byrsonima crassifolia (L.) H.B.K., two typical tree species of the neotropical savannas. Although moist forest patches occur more often on lower slopes and narrow valley bottoms, they can also be found on mid- and upper-slopes and less often on ridges. Thus, these forest patches are not gallery forests as are found throughout the neotropics, but the result of deforestation and fractionation of a continuous forest. A comparison of soil profiles between the savannas and remnant forest patches on the same slope, showed the disappearance of the A and B horizons (approx. 50 cm) under savanna vegetation. The sharp difference between the savanna and forest soils at the Rio Ranchería does not appear to be due to a change in soil water status along a toposequence or differences in the underlying bedrock. We hypothesize that the savannas of the Rio Ranchería watershed, are the result of deforestation and land practices on infertile soils derived from granite. The savannization process was likely initiated by Amerindians by means of the frequent use of fire or clearing lands for the cultivation of maize. The introduction of cattle by Spaniards (c. 1530) and the frequent use of fire to maintain grazing fields, contributed to further degradation of the habitat. While some tropical landscapes recovered their forest cover when human pressure was removed approximately 500 years ago, areas such as the Rio Ranchería watershed have suffered permanent damage. The savannas of this region are likely to remain unless fire is suppressed and soil restoration practices implemented.     

Barriers to Lowland Tropical Forest Restoration in the Sierra Nevada de Santa Marta, Colombia

Extensive areas of the tropics have been converted into pasture for cattle ranching. Frequently, abandoned pasture does not revert to forest. The goal of this project was to identify barriers to lowland moist forest regeneration in highly degraded grasslands in the Sierra Nevada de Santa Marta, Colombia. The barriers we considered were seed source, seed predation, competition with grasses, microclimate and soil limitations on plant growth, and fire. Seed dispersal into the grasslands is limited to within 10 meters of forest fragments, but this barrier can be overcome by sowing seeds and planting seedlings and by establishing perches to attract dispersers. In these degraded grasslands, seed predation was lower than in the adjacent forest patches, and there was no evidence that grasses inhibited the establishment of woody species. The most important barrier was the severe degradation of the soils. In much of the area, the A and B horizons have been eroded away, leaving saprolite at the soil surface. Seedlings of two fast-growing pioneer species, Ochroma pyramidale and Cochlospermum vitifolium, grew to a maximum height of only 2.5 and 12 cm, respectively, during the first eight months. The slow plant growth in the degraded grassland soils compared to forest soils was associated with lower levels of cation-exchange capacity, calcium, magnesium, and potassium. Even if these barriers could be overcome, the frequent and extensive use of fire in the region must be controlled to avoid killing established woody plants.     

A New Species of Terrestrial Isopoda from the Sierra Nevada de Santa Marta,Colombia (Crustacea: Oniscidea: Crinocheta)

A new species of the neotropical genus Ischioscia Verhoeff, 1928 is described from the Sierra Nevada de Santa Marta, Colombia: Ischioscia curvaculeus spec. nov. It is characterised by a hook on the merus of the male pereopod 7 not found in any other species of this genus. It was found in the rain forest at an altitude of 1700 m. The phylogeny of the new species is discussed and a note on the biogeography of the Santa Marta region is given.     

Reproduction of Joturus pichardi and Agonostomus monticola (Mugiliformes: Mugilidae) in rivers of the Sierra Nevada de Santa Marta, Colombia

The freshwater mugilids Joturus pichardi and Agonostomus monticola, have been documented on ecological and distribution aspects, mainly for Central American populations, nevertheless, little information is available on their reproductive aspects, specifically in Colombian freshwater environments. Reproductive biology of the mugilids J. pichardi and A. monticola from Sierra Nevada de Santa Marta (SNSM) rivers was studied between July 2005 and December 2006. A total of 14 specimens of J. pichardi and 320 of A. monticola were collected. The reproductive biology was analyzed by means of: sexual proportion, gonadosomatic index, and mean size at maturity, fecundity and oocyte diameter. Additionally, a bioassay was carried out to evaluate the effect of salinity on spermatic motility and its possible relationship with the species' spawning area. These mugilids share habitats with similar ecological characteristics, in which strong currents; clear water and stony areas stand out. Gonadal maturity indicators and indirect evidence are presented to support the relationship between reproductive maturity and higher rainfall levels in the area (September, October and November), as well as the catadromous migration of J. pichardi and A. monticola. This last species females outnumbered males with a sex ratio of 2.3:1. Females mean size at maturity was 172mm of their total length (TL) and 108mm TL for males. Fecundity (F) was 23 925 +/- 4 581 eggs per gram of gonad, and was related to size by the equation F = 395.1TL(1.281); besides, the mean oocyte diameter was 362 +/- 40 microm. Considering the salinity effect on sperm motility in both species, results suggested that J. pichardi spawned in estuarine environments but the species did not migrate to fully marine environments; however, A. monticola withstood a broad range of salinity, suggesting a spawning from intermediate to total saline environments. Both species have high culturing potentials, considering that their feeding is based on plant and macroinvertebrates, their meat quality and the size they are able to reach. These species represent an interesting resource to the fisher groups of the region and should be integrally assessed.     

Multi-criteria spatial identification of carnivore conservation areas under data scarcity and conflict: a jaguar case study in Sierra Nevada de Santa Marta,Colombia

Human–wildlife conflict, habitat loss, and prey hunting are the main threats to carnivore species worldwide. Forest conversion as consequence of deforestation and agricultural expansion increases the proximity between carnivores and humans, thereby escalating conflicts. Knowledge about carnivore species in data-poor countries, such as Colombia, is scarce which has the potential to result in poor landscape planning decisions. For many species, the only existing spatial information resides in expert-driven approaches which result in coarse-resolution ‘extent-of-occurrence’ maps. There is an increasing need for the development of methodologies to identify conservation and management areas at appropriate scales. Multi-criteria approaches will allow the inclusion of diverse species attributes enabling environmental institutions to address complex landscape decisions that result in conservation and management of carnivore habitat. We present a multi-criteria spatial identification tool for conservation and management areas, focused on Jaguars (Panthera onca) in the Sierra Nevada de Santa Marta, in northern Colombia. Our approach identifies areas based on the relationship between three spatial criteria: (1) suitable habitat patches, (2) habitat connectivity, and (3) zones of higher likelihood of human–jaguar conflict. We identified areas with the presence of at least one spatial criteria in 32% of the study area. Only 16.28% of these occur within protected areas (PAs) and the remaining fall on private lands (83.72%), either within (35.68%) or outside (48.04%) buffer zones of PAs. Our results highlight the need for multi-stakeholder collaborative approaches given that most proposed conservation areas fall on private rather than public lands.     

Notes on the behavior and ecology of Reliquia santamarta,an Alpine butterfly (Lepidoptera: Pieridae) from the Sierra Nevada de Santa Marta,Colombia, with comparisons to Nearctic Alpine Pierini

Reliquia santamarta is an unusual Pierine butterfly endemic to the Sierra Nevada de Santa Marta of northeastern Colombia, where it flies above 3500 m. Its biology is of particular interest because of the possibility that it might be a relict derived from the otherwise Holarctic Pieris callidice group, which it strongly resembles phenotypically. Its behavior was studied afield for comparison with Nearctic members of that group. Male R. santamarta are vigorous hilltoppers, assembling to topographic prominences, while females are frequently encountered at lower elevations. Flight patterns, thermoregulatory postures, and interactions between and within the sexes are all virtually identical to high‐montane and alpine Nearctic Pieris. The natural host plant was not determined. The role of seasonality in the biology of R. santamarta is discussed. Behavior data alone are inadequate to determine whether R. santamarta is closely related to or strongly convergent with the Nearctic taxa.     

Phylogeny of Riama (Squamata: Gymnophthalmidae), impact of phenotypic evidence on molecular datasets,and the origin of the Sierra Nevada de Santa Marta endemic fauna

Riama is the most speciose genus of the Neotropical lizard family Gymnophthalmidae. Its more than 30 montane species occur throughout the northern Andes, the Cordillera de la Costa (CC) in Venezuela, and Trinidad. We present the most comprehensive phylogenetic analysis of Riama to date based on a total evidence (TE) approach and direct optimization of molecular and morphological evidence. Analyses use DNA sequences from four loci and 35 phenotypic characters. The dataset consists of 55 ingroup terminals representing 25 of the 30 currently recognized species of Riama plus five undescribed taxa, including an endemic species from the Sierra Nevada de Santa Marta (SNSM) in Colombia, and 66 outgroup terminals of 47 species. Analysis results in a well‐supported hypothesis in which Riama is polyphyletic, with its species falling into three clades. The Tepuian Anadia mcdiarmidi nests within one clade of Riama, and the recently resurrected Pantodactylus nests within Cercosaura. Accordingly, we propose a monophyletic taxonomy that reflects historical relationships. Analysis of character evolution indicates that the presence/absence of prefrontals—a cornerstone of the early genus‐level taxonomy of cercosaurines—is optimally explained as having been plesiomorphically present in the most recent common ancestor of Cercosaurinae and lost in that of the immediately less inclusive clade. Multiple independent reversals to present and subsequent returns to absent occur within this clade. To evaluate the impact of phenotypic evidence on our results, we compare our TE results with results obtained from analyses using only molecular data. Although phenotypic evidence comprises only 1.2% of the TE matrix, its inclusion alters both the topology and support values of the clades that do not differ. Finally, current phylogenetic evidence reveals a SNSM–CC–Trinidad–tepuis biogeographical link. We hypothesize that an ancient connection facilitated the exchange of species between the SNSM and the CC.     

Seasonal variations of bacterial abundance and biomass and their relation to phytoplankton in the hypertrophic tropical lagoon Cienaga Grande de Santa Marta, Colombia

The seasonal development of bacteria was studied in the hypertrophiccoastal lagoon Ciénaga Grande de Santa Marta (Caribbeancoast of Colombia). This large but only 1.5 m deep lagoon issubject to strong seasonal variations of salinity from almostfully marine (April/May) to brackish conditions in October/November.Chlorophyll ranged from 6 to 182 µg L^–1, and grossprimary production amounted to 1690 g C m^–2 per year.Total bacterial number (TBN) ranged from 6.5 to 90.5 x 10⁹ cellsL^–1 and bacterial biomass (BBM) from 77 to 1542 µgC L^–1, which are among the highest ever reported for naturalcoastal waters. Neither TBN nor BBM varied significantly withsalinity, phytoplankton or seston concentrations. Only the bacterialmean cell volume showed a significant relation to salinity,being highest (0.066 µm³) during the period of increasingand lowest (0.032 µm³) during decreasing salinity. Bacterialprotein accounted for 24% (19–26%) and phytoplankton proteinfor 57% (53–71%) of total seston protein. The ratio (annualmean) of bacterial carbon to phytoplankton carbon was 0.44 (range0.04–1.43). At low phytoplankton abundance [chlorophylla (Chl a) < 25 µg L^–1], bacterial carbon wasalmost equal to phytoplankton biomass (i.e. the mean ratio was1.04). In contrast, at Chl a > 100 µg L^–1, BBMwas low compared to phytoplankton biomass (the mean ratio was0.16). In general, BBM varied less than phytoplankton biomass.Most probably, the missing correlation between bacterial andphytoplankton variables was due to (i) organic material partlyderived from allochthonous sources serving as food resourcefor bacteria and (ii) a strong resuspension of bacteria fromthe sediment caused by frequent wind-induced mixing of the veryshallow lagoon.     

Hybridization between two parapatric ranid frog species in the northern Sierra Nevada,California, USA

Contact zones between species provide a unique opportunity to test whether taxa can hybridize or not. Cross‐breeding or hybridization between closely related taxa can promote gene flow (introgression) between species, adaptation, or even speciation. Though hybridization events may be short‐lived and difficult to detect in the field, genetic data can provide information about the level of introgression between closely related taxa. Hybridization can promote introgression between species, which may be an important evolutionary mechanism for either homogenization (reversing initial divergence between species) or reproductive isolation (potentially leading to speciation). Here, we used thousands of genetic markers from nuclear DNA to detect hybridization between two parapatric frog species (Rana boylii and Rana sierrae) in the Sierra Nevada of California. Based on principal components analysis, admixture, and analysis of heterozygosity at species diagnostic SNPs, we detected two F1 hybrid individuals in the Feather River basin, as well as a weak signal of introgression and gene flow between the frog species compared with frog populations from two other adjacent watersheds. This study provides the first documentation of hybridization and introgression between these two species, which are of conservation concern.     

Population estimation in the Torrent frog, Amolops lamtensis (Anura: Ranidae)

The results of four attempts at yearly intervals to estimate populations of Amolops lamtensis (Blgr.) along 360 m of forest stream are discussed and the most consistent estimates are obtained using Jolly's (1965) method of analysing such data. Observations of movement within the population indicate that most frogs are recaptured close to the original point of capture although a few show considerable downstream movement, possibly as a result of being swept away by the current. The recapture expectations are not, however, random and there is a strong indication that larger frogs are more liable to recapture. There is also evidence that frogs are available for recapture for different lengths of time, and it is likely that this leads to an under-estimate of the total population.     

Concentrations of trace metals in Ariopsis bonillai (Pisces: Siluriformes) of Santa Marta, Colombian Caribe]

To determine changes in the contents of some heavy metals (Cd, Zn, Cu) in the fish Ariopsis bonillai, at Ciénaga Grande de Santa Marta, Colombia, monthly samples were taken between July 1987 and June 1988. The highest concentrations in the muscle appear between November and February (4.24 micrograms Cd/g, 109.4 micrograms Zn/g and 13.3 micrograms Cu/g), during the periods of lower salinity, at the end of the rainy season, and at the beginning of the dry season. Metals were measured also in the liver: values for Zn and Cu were ten times higher than in the muscle. About the first half of the year, the values tend to be similar. Cd differences were not as strong as for the other metals.     

Development of the nasal chemosensory organs in two terrestrial anurans: the directly developing frog, Eleutherodactylus coqui (Anura: Leptodactylidae), and the metamorphosing toad, Bufo americanus (Anura: Bufonidae)

Nearly all vertebrates possess an olfactory organ but the vomeronasal organ is a synapomorphy for tetrapods. Nevertheless, it has been lost in several groups of tetrapods, including aquatic and marine animals. The present study examines the development of the olfactory and vomeronasal organs in two terrestrial anurans that exhibit different developmental modes. This study compares the development of the olfactory and vomeronasal organs in metamorphic anurans that exhibit an aquatic larva (Bufo americanus) and directly developing anurans that have eliminated the tadpole (Eleutherodactylus coqui). The olfactory epithelium in larval B. americanus is divided into dorsal and ventral branches in the rostral and mid-nasal regions. The larval olfactory pattern in E. coqui has been eliminated. Ontogeny of the olfactory system in E. coqui embryos starts to vary substantially from the larval pattern around the time of operculum development, the temporal period when the larval stage is hypothesized to have been eliminated. The nasal anatomy of the two frogs does not appear morphologically similar until the late stages of embryogenesis in E. coqui and the terminal portion of metamorphosis in B. americanus. Both species and their respective developing offspring, aquatic tadpoles and terrestrial egg/embryos, possess a vomeronasal organ. The vomeronasal organ develops at mid-embryogenesis in E. coqui and during the middle of the larval period in B. americanus, which is relatively late for neobatrachians. Development of the vomeronasal organ in both frogs is linked to the developmental pattern of the olfactory system. This study supports the hypothesis that the most recent common ancestor of tetrapods possessed a vomeronasal organ and was aquatic, and that the vomeronasal organ was retained in the Amphibia, but lost in some other groups of tetrapods, including aquatic and marine animals.