Magdalena River Valley Research Articles

Diet of Engystomops pustulosus (Anura: Leptodactylidae) from Colombia and current knowledge of its dietary


 
 
 
 We investigated the diet of Engystomops pustulosus from a population in the Middle Magdalena River valley, including an evaluation of theeffect of body and head size on prey number and volume. We present the current state of knowledge of the diet of E. pustulosus from published information in addition to our data. We found a total of 400 prey items representing two phyla, Arthropoda and Mollusca; seven orders and nine families were detected. Arthropods, mainly insects, were the most frequent prey in the diet. Among arthropods, Acari and Isoptera were numerically dominant. We did not observe effects of body and head size on prey number and volume. The published literature of the diet of E. pustulosus included 66 prey items, among which Isoptera (termites), Acari, and Formicidae were the most common groups, suggesting dietary specialization. Prey items consumed by E. pustulosus varied among different localities; Blattodea, Orthoptera, and Thysanoptera were unique at certain localities. Further study of prey availability and diets associated with land-use changes across majorgeographic localities will contribute to a better understanding of the predator-prey interactions in these anthropogenic environments.
 
 
 

Distribution and conservation of vanilla crop wild relatives: the value of local community engagement for biodiversity research

Natural vanilla is a high-value crop with demand increasing globally. Crop wild relatives (CWR) represent valuable agrobiodiversity and are prioritized in the Global Strategy for Plant Conservation. Vanilla species are naturally rare with historically infrequent botanical collections. Despite their importance as CWR, fewer than 10% of Vanilla species have been evaluated for the IUCN Red List. Colombia is a diversity center for Vanilla species, yet many remote regions are lacking detailed floristic characterization. We show that the participation of rural communities in scientific endeavor enhances capacity to register biodiversity. We report two Vanilla species in the under-explored region of the Serranía de las Quinchas in the mid–Magdalena River valley in Colombia, including the first report for Colombia of Vanilla karen-christianae. For this, and the second species, Vanilla dressleri, we present descriptions with photographic botanical illustrations, updated distribution maps, and preliminary conservation status assessment. Both species are of elevated conservation concern, categorized as Endangered – EN: B2a,b(ii,iii,iv,v) following IUCN criteria. Within Colombia, all recorded occurrences for both species fall outside protected areas. Vanilla crop wild relatives in Colombia have urgent conservation needs. The Serranía de las Quinchas is a priority for further botanical exploration for Vanilla, as well as other protected areas with appropriate habitat. In situ conservation should be complemented with ex situ actions. Community participation in biodiversity research is recommended in this and other remote regions as an integral step towards enhancing biodiversity research and community-based conservation.

First records of Loxopholis southi (Ruthven & Gaige, 1924) (Squamata, Gymnophthalmidae) in the Cordillera Oriental of the Colombian Andes

We present the first records of Loxopholis southi (Ruthven & Gaige, 1924) from the western slope of the Cordillera Oriental in Colombia. This species had previously only been known from the biogeographic regions of Chocó and Magdalena River valley in the Cordillera Occidental and Central Colombia, and from Central America. This record expands the distribution of L. southi to the Andean mountains of the Cordillera Oriental, crossing the Magdalena River valley. It now constitutes the easternmost known occurrence in Colombia and the highest altitudinal record for this species.

Sequential use of niche and occupancy models identifies conservation and research priority areas for two data-poor endemic birds from the Colombian Andes

AbstractThe lack of high-quality information on data-poor species can hinder efforts to inform conservation actions via spatial distribution modeling. This is particularly true for tropical birds of conservation concern, for which ecological studies and assessments of their conservation status have received limited funding. Here we use a cost- and time-efficient protocol for assessing the distribution of range-restricted taxa and to identify priority areas for their conservation based on a sequential application of environmental niche models (ENMs) and occupancy-detection models. This approach first uses available geographical information and niche-theory to prioritize potential study sites, which can later be surveyed to obtain high-quality presence–absence data to accurately model distributional ranges with limited resources. We apply this protocol to identify priority areas for two Neotropical birds of conservation concern endemic to the Colombian Andes: Yellow-headed Brush-finch (Atlapetes flaviceps) and Tolima Dove (Leptotila conoveri). We first fitted ENMs using spatially filtered datasets containing all available records up to 2018. We then conducted field surveys across climatically suitable areas identified for both species, carrying out a total of 1,750 counts to generate input data for the occupancy models. Overall, our results suggested more extended and more continuous distribution ranges for both species than previously reported, but also identified population strongholds that are not currently represented within the national protected areas system. Both species occupied a narrow elevational belt (~1,300–2,600 m above sea level) of the Central Andes of Colombia primarily on the slopes of the Magdalena River valley, with isolated populations in the Western and Eastern Andes; these areas have undergone some of the most marked landscape transformations in Colombia. This straightforward protocol maximizes available information and minimizes costs, while allowing for estimation of occurrence probabilities for range-restricted, data-poor taxa.

The role of unprotected and privately protected areas for ocelot conservation: densities in Colombia and Brazil

AbstractThe ocelot (Leopardus pardalis) is a widely distributed, medium-sized felid in the Americas with declining population size. We estimated ocelot densities and home ranges in one agricultural area in the Magdalena River valley in Colombia, a private reserve and cattle ranch in the Colombian Llanos, and a private reserve in the Serra do Amolar in the Brazilian Pantanal. We used camera trapping (39–52 stations) and spatially explicit capture-recapture (SECR) models. Density estimates (individuals/100 km2) were 11.0 ± 2.7 (SE) in the Magdalena River valley; 13.2 ± 3.2 (SE) in the Llanos, and 10.3 ± 2.9 (SE) in the Serra do Amolar. Overall, despite an impact of agriculture and human disturbance, our results highlight the importance of unprotected areas and privately protected ranching areas for ocelot conservation. As agriculture continues to expand across the tropics causing habitat loss, and negatively affecting ocelot densities, we recommend land use planning and best agricultural practices to maintain natural habitats, thereby limiting human impacts on ocelot conservation.

Features of atmospheric deep convection in northwestern South America obtained from infrared satellite data

AbstractAtmospheric deep convection in equatorial continental regions is not homogeneously distributed in space or time, primarily due to surface inhomogeneities such as elevated topography and coastlines. This is the case in northwestern South America, which has particularly complex topography which, together with its geographical location, is responsible for some of the most prominent precipitation features around the globe. Although some of these features have been previously investigated in detail, others have not yet been studied, and some not even documented in the literature. The diverse atmospheric convective activity that takes place in this region constitutes a natural laboratory that can provide important insights into fundamental questions relevant for global climate. We use seven years of infrared brightness temperature data in 30 min intervals from the GOES‐13 geostationary satellite to estimate the spatial, seasonal and diurnal distributions of deep convective events in this region. By doing so, we bring forward several relevant features, providing a starting point for future investigations. For example, we find that deep convective events have a bimodal seasonal distribution throughout most of the Colombian Orinoco and Amazon basins, where precipitation is known to have a unimodal distribution. Furthermore, deep convective events in this region tend to be comparable in size to those offshore the Colombian Pacific coast or over the Magdalena river valley, but with significantly shorter lifetimes. On the other hand, nocturnal convection dominates at several continental locations; one of these, the middle‐lower Magdalena river valley, has been previously identified as one of the most active lightning hotspots on Earth, but its convective mechanisms have not yet been fully investigated. Another such location worth investigating is the middle Magdalena river valley, which may have strong similarities with the Maracaibo Lake area.

Effect of landscape modification on primate assemblages of the Magdalena River Valley, Colombia

Population and community dynamics are affected by local landscape disturbances, and the answer of each species to these changes could differentially affect species survival. Natural land cover in the Magdalena River valley, Colombia, has been reduced by almost 70 % and fragmented. There inhabit isolated and reduced populations of Alouatta seniculus, Ateles hybridus, Cebus versicolor, and Saguinus leucopus (Primates). To understand the effect of fragmentation over these species, the relationship between altitude, landscape and class metrics, and plant structure and diversity with the population density of these four primates in 20 localities were assessed. Additionally, the relationship between the density of A. hybridus, assumed as a better competitor, and the density of the other primates was assessed. Mean shape index was the most related variable and affected positively the density of A. hybridus, C. versicolor, and S. leucopus and negatively that of A. seniculus. Weight class index was the second more important variable, the four primates increased their density where more mature is the plant cover. Diameter at breast height was positively related with the density of A. hybridus and C. versicolor, negatively related for A. seniculus and not related to S. leucopus density. Tree density was related negatively with the density of A. seniculus and positively with S. leucopus. A. hybridus was related to the density of the other primates, positively to A. seniculus and negatively to the other two species.

First record of Colombian red-eyed tree frog Agalychnis terranova from the Sierra Nevada de Santa Marta, Colombia with a description of its advertisement call

Based on collected specimens and phylogenetic information, we provide the first record of the Colombian redeyed tree frog, Agalychnis terranova, from the Sierra Nevada de Santa Marta in northern Colombia. This species is known from several localities on the middle Magdalena river valley and the Pacific lowlands. With this new record, the known geographic distribution of this frog is extended about 370 km north-west from its previous northernmost record. Additionally, we describe for the first time the tonal advertisement call of this species, which consisted of one or two notes with a total duration of 0.52 s and dominant frequency of about 1.74 kHz.

Demography of <i>Attalea nucifera</i>: Sustainable management and conservation of a threatened species of Colombia

Attalea nucifera is an acaulescent palm native of Colombia that is in risk of extinction. Between 2016-2017 we evaluated the structure and density of populations in six localities of the Magdalena river valley, and studied the population dynamic in the locality of Guaduas, Cundinamarca (VC). Although the population structure differs among locations (X2 = 1819, gl = 25, P < 0.05), populations tend to group according to the degree of habitat perturbation. In four localities an inverted J population structure was observed. A matrix population model showed a finite growth rate (λ) of 0.979 (CI95 % = 0.962–0.997). The demographic processes of the permanence of seedlings, sub-adults and young adults show more elasticity. A transient dynamic simulation projected to 30 years shows that under the scenarios of paddock and cattle lopping the population size decrease drastically. The extinction threshold calculated for the population in the locality VC is of 145 years, but paddock and cattle lopping activities can reduce it to less than 40 years. Although Attalea nucifera persists in very disturbing locations in the Middle Magdalena Basin, the results of population dynamics in the locality VC suggest that it could be less tolerant of environmental disturbances. Thus, it is necessary to increase our knowledge of its population dynamics, as well as seed germination and seedling establishment in different disturbance conditions.

Description of a new diminutive Hyloxalus (Anura: Dendrobatidae: Hyloxalinae)from the Magdalena Valley of Colombia.

Using different sources of evidence (i.e., integrative taxonomy), we describe a new species of Hyloxalus, Hyloxalus arliensis sp. nov. The new species occurs in the middle Magdalena River valley on slopes between the Cordillera Central and Cordillera Oriental of the Andes of Colombia. Previously, the new species was referred to as Hyloxalus "Ibagué" but was not formally described. Phylogenetic re-analyses of 2440 base pairs (bp) of mitochondrial DNA (mtDNA), revealed the species to be a sister taxon of H. lehmanni, within a monophyletic clade also comprising H. delatorreae lineage 1, H. pulchellus and H. vertebralis. The adult males of H. arliensis sp. nov. have a pale arm gland, which differentiates it from all other species of the genus, except for H. saltarius. The new species also differs from other species of Hyloxalus by its smaller size, disc on Finger III not expanded, toes unwebbed, dorsolateral stripe absent, oblique lateral stripe present, white spots on ventrolateral flanks in life and cloacal tubercles absent. The advertisement call consists of long trains of a single note repeated at a rate of 89-132 notes/min with a dominant frequency ranging from 4808-6387 Hz. The new species is a tiny frog that inhabits the sheltered areas around streams in sub-Andean forests. Aspects of its natural history are described.

The arrival of wagons to the Andes: Construction of the Cambao Wagon Road in 1880s Colombia

The slow adoption of wagon roads on the Andes is an event widely noted. In this article we document the arrival of the first wagon road to the Andes: the Cambao wagon road connecting Bogotá to the Magdalena river valley in 1885. The road projects, its construction and traffic once it opened are presented and discussed using a variety of newly identified archival sources. It is argued that the historic and economic significance of this technological milestone was probably obscured by the all too soon expected arrival of railways.

Rediscovery of the enigmatic forest racer snake, Dendrophidion boshelli Dunn, 1944 (Serpentes, Colubridae): actions for the conservation of a critically endangered species

Dendrophidion boshelliis a poorly known and endemic snake species from the Middle Magdalena river valley in Colombia. It was described in 1944 based on a single specimen from the municipality of Caparrapí, department of Cundinamarca. Since the original description, only three additional specimens have been established. As part of the results of a herpetological monitoring in the Miel I Hydroelectric project, department of Caldas-Colombia, three additional specimens ofD. boshelliwere found in 2014–2015. The specimens represent the second known population of the species. We presented morphological data and pholidosis; description of the coloration in life, and a description of the habitat. Recently,D. boshelliwas included as a Critically Endangered (CR) species in the Red Book of Reptiles of Colombia, and the IUCN Redlist. For this reason, to promote the local conservation of this and other endemic and threatened species in the Miel I area, we suggested some actions at the local level, such as establishing a conservation area with legal status in the Middle Manso River basin, which is a tributary of the Miel I Hydroelectric project.

Wetlands are keystone habitats for jaguars in an intercontinental biodiversity hotspot.

Agricultural development was the major contributor to South America’s designation as the continent with the highest rates of forest loss from 2000–2012. As the apex predator in the Neotropics, jaguars (Panthera onca) are dependent on forest cover but the species’ response to habitat fragmentation in heterogeneous agricultural landscapes has not been a subject of extensive research. We used occupancy as a measure of jaguar habitat use in Colombia’s middle Magdalena River valley which, as part of the intercontinental Tumbes-Chocó-Magdalena biodiversity hotspot, is exceedingly fragmented by expanding cattle pastures and oil palm plantations. We used single-season occupancy models to analyze 9 months of data (2015–2016) from 70 camera trap sites. Given the middle Magdalena’s status as a “jaguar corridor” and our possible violation of the occupancy models’ demographic closure assumption, we interpreted our results as “probability of habitat use (Ψ)” by jaguars. We measured the associations between jaguar presence and coverage of forest, oil palm, and wetlands in radii buffers of 1, 3, and 5 km around each camera trap. Our camera traps recorded 77 jaguar detections at 25 of the camera trap sites (36%) during 15,305 trap nights. The probability of detecting jaguars, given their presence at a site, was 0.28 (0.03 SE). In the top-ranked model, jaguar habitat use was positively influenced by wetland coverage (β = 7.16, 3.20 SE) and negatively influenced by cattle pastures (β = -1.40, 0.63 SE), both in the 3 km buffers. We conclude that wetlands may serve as keystone habitats for jaguars in landscapes fragmented by cattle ranches and oil palm plantations. Greater focus on wetland preservation could facilitate jaguar persistence in one of the most important yet vulnerable areas of their distribution.

Richness, diversity, and factors influencing occupancy of mammal communities across human-modified landscapes in Colombia

As human-modified landscapes are increasing in the tropics, it becomes critical to understand how they affect mammal communities to reconcile conservation and development. We combined land cover information and camera-trapping data to explore the effects of agricultural expansion on mammals in the Magdalena river valley of Colombia. We estimated species diversity, evenness, and dominance across two agricultural landscapes, modified by cattle ranching and oil palm cultivation. We further assessed which variables influence species- and community-level occupancy using multi-species occupancy models. Results highlight that modified landscapes display lower species richness, diversity and evenness, and higher dominance than more pristine sites. Residual forest cover and distance to water had significant effect on community occupancy (positive and negative respectively). Forests were particularly important for pumas, ocelots, lowland pacas, Central American agoutis, and crab-eating raccoons while wetlands had a positive effect on jaguars, the apex predator in the region. The influence of anthropogenic pressure was not clearly evident, though pastures were not valuable habitats for any mammal species, as they had a negative, yet not significant, effect on species and community occupancy. In light of rapidly expanding agriculture across the tropics, our findings highlight species-specific responses to disturbance that can inform land use planning and conservation policies. We stress the conservation value of forest and wetland habitat to mammal occupancy in heterogeneous ecosystems. Moreover, our results demonstrate that oil palm and crop expansion should target existing pastures, which displayed limited conservation value for Neotropical mammals but occupy vast swathes of land across Latin America.

The effect of natural gas composition and atmospheric humidity on premixed combustion across the regions of Colombia

As a tropical and highly mountainous country, Colombia has varying levels of atmospheric humidity across its regions. These humidity levels affect combustion parameters in premixed combustion systems such as laminar burning velocity, adiabatic flame temperature, and pollutant emissions. The greatest effect of water in the reaction zone is the reduction of NOx formation (at equilibrium) by up to 40% through the thermal mechanism for lean mixtures. The laminar burning velocity is reduced by up to 25% at an equivalence ratio of 0.5 and a molar moisture content of 3.5%. This effect is reduced near the stoichiometric point due to the higher adiabatic flame temperature. The natural gas mixtures from the Cusiana and Guajira fields were analyzed. The same combustion property changes were obtained for both fuels when the reaction zone water content was varied. However, the Cusiana gas had a higher absolute flame temperature, laminar flame speed, and pollutant emissions than the Guajira gas, due to its greater heavy hydrocarbon content. This work presents the analysis and the resulting favorable-combustion map for the regions of Colombia. Therein is shown that Bogotá and its surroundings are the most prone to NOx emissions due to the region’s low atmospheric moisture content; less than 1.5% molar fraction. As a consequence, this area should implement tightened emissions monitoring and regulation. In contrast, the Atlantic coast and the Magdalena river valley are the regions of Colombia that have the best conditions for combustion due to their high moisture content; greater than 3.5% molar fraction. This makes them the preferred regions for the installation of combustion systems and thermal power generation plants from the point of view of minimizing operational instabilities and pollutant emissions. For example, at high pressure and temperature, the humidity has an appreciable effect on the laminar flame speed, reducing it by up to 25% at the equivalence ratio of 0.5. This effect lessens as the mixture shifts towards the stoichiometric point due to the higher adiabatic flame temperature.

Imantodes inornatus (Boulenger, 1886) (Squamata: Dipsadidae): expansion of known range and first records from the Magdalena River valley, Colombia

Imantodes inornatus (Boulenger, 1886) (Squamata: Dipsadidae): expansion of known range and first records from the Magdalena River valley, Colombia

Imantodes inornatus (Boulenger, 1886) (Squamata: Dipsadidae): expansion of known range and first records from the Magdalena River valley, Colombia

The first report of the Speckled Blunt-headed Tree Snake ( Imantodes inornatus ) is presented for the Magdalena River valley, from the departments of Antioquia, Bolivar, Boyaca and Caldas in Colombia. Since these records correspond to the biogeographic Magdalena province, the known range for the species is expanded. In Colombia, this is a trans-Andean species found from the Pacific rainforests of the Choco region, through the northern portion of the Western and Central Andean ranges, to the middle Magdalena River valley.

Aves del departamento de Cundinamarca, Colombia: conocimiento, nuevos registros y vacíos de información

The department of Cundinamarca in Colombia is an area with diverse geographic and ecosystemic characteristics, a condition that makes it one of the regions in the country with highest diversity of birds. This study updates the list of birds in the department, as well as identifies changes in composition and gaps of information, through the recopilation of field data developed by the authors from 1990 to 2015, revision of different papers and databases, and consultation of experienced birdwatchers in the region. We found 941 records of bird species, of which 24 are endemic, 72 near endemic, 1 extinct, 39 nationally threatened, 101 migratory, and 45 present local and/or altitudinal migration. Of the total number of records, 701 correspond to the authors in 45 localities (48 are new records for the department). We note that there are gaps of information in departmental boundaries, especially in the region of the Magdalena River valley and Llanos Orientales. However, regions that have been more extensively sampled are not fully inventoried since new species for science are still being found.

Seasonality, richness and prevalence of intestinal parasites of three neotropical primates (Alouatta seniculus, Ateles hybridus and Cebus versicolor) in a fragmented forest in Colombia.

Studies on parasites infecting non-human primates are essential to better understand the potential threat to humans of zoonoses transmission, particularly under the current processes of pervasive land use change and biodiversity loss. The natural ecosystems in the Middle Magdalena river basin in Colombia have suffered a dramatic reduction and transformation into pastures and agroindustrial monocultures, threatening their biodiversity, and probably affecting the dynamics between parasites and their hosts, as well as altering the disease transmission cycles between wild populations and humans. This study evaluated seasonality, prevalence and richness of intestinal parasites in three species of neotropical primates: Cebus versicolor, Ateles hybridus and Alouatta seniculus, in a fragmented forest in the Middle Magdalena river valley, Colombia. One hundred and eighty five faecal samples were collected between 2010 and 2015. Direct faecal smears were performed with saline solution (0.85%) and iodine solution (1%), in order to identify larvae and eggs based on their morphology. A large proportion of the samples examined (72.9%) was positive for intestinal parasites; seven families of nematodes were identified: Trichuridae, Trichostrongylidae, Oxyuridae, Strongyloididae, Ancylostomatidae, Ascarididae and Gnathostomatidae, two of protozoans: Entamoebidae and Balantiididae, as well as some eggs of trematodes, cestodes and acanthocephalans. Additionally, DNA extraction and sequencing were conducted on 30 faecal samples in order to identify Giardia sp. and Blastocystis hominis, two parasite species also present in humans. Molecular testing for Giardia sp. was negative and Blastocystis hominis was identified in a single sample of Alouatta seniculus. No clear patterns were observed for prevalence of intestinal parasites according to the season; nonetheless, parasite species richness was higher during the dry season. This study builds on our current understanding of intestinal parasites infecting wild neotropical primates and provides novel information on the patterns of intestinal parasites in primate communities exposed to anthropogenic disturbance.

Atypical colororation in the yellow-striped poisonous frog, Dendrobates truncatus (Cope, 1861), in the Colombian Magdalena river valley.

Herein we report an atypical colororation in the yellow-striped poisonous frog, Dendrobates truncatus (Cope, 1861), in Colombian Magdalena middle valley. This phenomenal corresponds to leucism pattern, which refers an albinism with a normal ocular pigmentation. This records provide an important input in natural history knowledge in this species.