Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The continuous use of agricultural machinery in rice (Oryza Sativa L.) cultivation throughout its vegetative cycle increase in apparent density and resistance to penetration into the soil, which affects the development of the crop and its performance. Thus, seeking a more sustainable agriculture, it was proposed to evaluate the soil's physical properties and crop yield, modifying the conventional preparation with a harrow using a chisel on the USCO’s Farm in Palermo (Huila, Colombia). Four experimental treatments were implemented: three with different chisel passes and a control with conventional plowing, in which real density, bulk density, and porosity were evaluated before and after tillage, and after harvest. The statistical analysis was carried out through analysis of variance, and the techno-economic analysis was carried out based on the production and operation costs between the two types of tillage. The results showed that after tillage, the bulk density decreased by 13.5% in the control and 11.5% in T3. These effects increased porosity between 23.0 and 31.6% in the area with greater tillage. After the harvest, a resilient response of the soil was found, which recovered 9.5 and 12.4% of the apparent density in T3 and T4, respectively. The use of reduced tillage with chisel did not make a significant difference in production (Control: 7.8 t ha-1, T1 and T2: 8.2 t ha-1, and T3: 8.4 t ha-1), but it was more economical and less aggressive for the soil in structural terms.

Introduction: The sea cucumber, Holothuria (Halodeima) grisea, is a common species in intertidal rocky shores along the Brazilian coast. Due to its abundance, it is considered a potential resource for aquaculture development. Objective: To characterize some reproductive features of H. (H.) grisea in southern Brazil, including sex ratio, gonadosomatic and maturity indices, and macro and microscopical observations of gonad tubules. Methods: Adult individuals were randomly collected in August and October 2019; February, March, May, and October 2020 at the intertidal region during low tides on the coast of Santa Catarina, Brazil. The individuals were transferred to the laboratory, where they were subject to biometry, dissection, and preservation to further macro and microscopic examinations. Results: The sex ratio was 1 : 1 and the gonad indexes were similar in both sexes and between months. Two main cohorts (25.3 and 85.3 μm) and three cytometric intervals (CI) were established. Based on histology for males, and mainly cohorts and CI for females, the individuals were categorized into five stages of the gonadal development scale (GDS) in tubules: growing, premature, mature, spawning and post spawning. Maturation and spawning events were frequent in all months, mainly February, March, and May 2020. Seven colors of the tubules were presented (transparent, transparent-pink, white, transparent-white, creamy-white, cream, and pink) with a large overlap between sex and GDS. Conclusions: This study is the first to describe the reproductive behavior of H. (H.) grisea on the coast of Santa Catarina and this population exhibits a continuous reproductive pattern with reduction in winter season. Our results can offer a baseline for future research, providing various qualitative and quantitative description tools for greater effectiveness in understanding the maturity cycle of populations and managing the sea cucumber fishery in Brazil.

Introduction: Plant roots harbor communities of bacteria that can provide benefits to their host through the production of phytohormones, phosphate solubilization, and nitrogen fixation. In Mexico, there are few studies on the richness and diversity of rhizobacteria communities associated with ferns. Objective: To analyze and identify the functional groups of bacteria from the rhizosphere of Dryopteris pseudofilix-mas in Mount Tlaloc, Mexico. Methods: Rhizospheric soil from D. pseudofilix-mas was collected at four sites where this fern occurs naturally. Bacterial populations were quantified by the plate count and dilution method. The isolated strains were characterized and identified using the 16S rDNA gene. Physical and chemical characteristics of the soil were determined and data of soil moisture, temperature and light in the canopy were collected. Results: The total bacteria population was from 30.1 to 92.3 x 104 CFU g-1 soil. Soil pH and phosphorus content influenced the density of bacterial populations. About 108 bacterial strains were isolated, 92 were Gram-negative and 16 Gram-positive. The isolated strains belonged to 20 genera, being the most abundant Pseudomonas and Bacillus. The Sørensen index indicates that the species of bacteria are similar in the four sites; Pseudomonas jessenii was present in the four sites. The bacterial strains presented more than one plant growth promoting activity, being the group of nitrogen fixers the most abundant. Conclusions: The rhizosphere of D. pseudofilix-mas harbors diverse groups of functional bacteria that could potentially be used in biotechnology for ecological restoration or agricultural purposes. The bacterial population of the four sites was dominated mainly by Pseudomonas and Bacillus.

Introduction: Bioacoustics allows the study of the ecology and behavior of bats through the analysis of echolocation signals. In insectivorous bats, foraging strategies, prey preference, and habitat use are closely related to the emission patterns of echolocation signals. Identifying significant bat habitats and improving conservation efforts can benefit from understanding these relationships. Objectives: To describe the echolocation signals of an endangered species Neoeptesicus innoxius, and other commonly detected species in the study area, Myotis nigricans and Molossus molossus, to contribute to the construction of a bat echolocation call reference library in Western Ecuador. Methods: Mist nets were used to capture bats, and reference recordings were subsequently obtained using the Anabat Swift ultrasonic detector. Echolocation pulse selection for each species was carried out using Kaleidoscope Pro 5.6.8 and BatSound 4.2.1, measuring the following spectral and temporal parameters of the echolocation signals in the search phase: initial, final, and maximum energy frequency, pulse duration, and interpulse interval. Results: N. innoxius presented the echolocation signals with the greatest variability of the spectral and temporal parameters, emitting pulses with high modulation speed (with one prominent FM component), and of low modulation speed (with one prominent QCF component); M. nigricans emissions were characterized by broadband signals of very short duration; and M. molossus presented alternation in its echolocation signals, where both high and low pulses had very little variability. Conclusions: The acoustic description of an endangered species like N. innoxius alongside the descriptions of other species frequently detected at the same study site, contributes to the construction of a bat echolocation call reference library. This input is the basis of future research of the ecology and behavior of the insectivorous bats that inhabit the Western Ecuador, which in turn is very valuable for designing tools and strategies for bat conservation.

Introduction: Manglares are ecosystems that provide numerous benefits and environmental services to society. However, its extension is being reduced due to various human activities such as the change in soil use and coastal development, which is why studies are needed to determine the state of these ecosystems and thus propose actions for their rehabilitation. Objective: Characterize the structure and health status of manglar in the coastal sector Paraguay, Guantánamo, Cuba. Methods: The investigation took place in a mangrove forest in the coastal sector that borders Guantánamo Bay, in the eastern region of Cuba. Plots of 100 m2 aligned, perpendicular to the coast; The structure of the mangle is determined by height, diameter, basal area, volume, density and mortality. The relationship of these variables with the composition of mangle species was carried out through a Canonical Discriminant Analysis. To determine the state of health, the quotient of the number of identified tensors over the total of identified tensors is obtained, the result is the remainder and is multiplied by 100 to express it in complete numbers. Using the value obtained, the health status was classified following this scale: very high (from 100 to 71), high (from 70 to 67), medium (from 66 to 62), low (from 61 to 42) and very low (41 or less). Results: The average height of the head was 6.50 m, with a predominance of Avicennia germinans and average regeneration. New environmental tensors were identified, the majority with anthropic character and low intensity (88% are of anthropic origin and 12% are related to natural events). Conclusion: The health of the studied ecosystem presents a variation that goes from very high to low and is characterized by a low size.

Introduction: The genus Sechium P. Brown (Cucurbitaceae) includes 11 species, of which two are domesticated and nine grow in the wild. The Central American clade of Sechium has six species distributed in Panama and Costa Rica. These species have characteristics that can be transferred from wild to domesticated species. Objective: To use three machine learning stacking algorithms and multivariate tools to describe geographic distribution, diversity degree, and endemism, to identify major conservation areas and to promote research for the improvement of the domesticated species. Methods: Two hundred and nine occurrence records were retrieved from the Global Biodiversity Information Facility. Raster values extracted from 21 bioclimatic variables were analyzed with descriptive and multivariate statistics. The species distribution algorithms were assembled with the SSDM library from R software. Results: Most species are distributed in type A and C climates, mainly in volcanic soils, with abundant organic matter. These species can grow at altitudes exceeding 2 000 m and tolerate low temperatures and high humidity levels. K-medoids established two groups and a 0.39 average silhouette coefficient, which indicates a low clustering trend. The stacked distribution models recorded good performance in areas under the curve (AUC) (> 0.75) and true skill statistic (> 0.75). Conclusions: The main variables that supported the models were elevation, soil types, and precipitation. The main endemism and species diversity areas were in the Cordillera de Talamanca, the Cordillera de Guanacaste, the Cordillera de Tilarán, and the Central Volcanic Range (Costa Rica). These species thrive under similar environmental conditions; however, the diverse areas have significantly different precipitation and soil types.

Introduction: Harmful Algal Blooms (HAB) are the rapid growth of algae or cyanobacteria in water that can cause negative impacts on people, animals, or the environment by production of natural toxins. Information about HABs in the bays in Indonesia is limited. Objective: To predict HABs based on the type and abundance of phytoplankton in the northern part of Bone Bay, South Sulawesi, Indonesia. Methods: The study was conducted in four locations, namely Tj Ringgit (TR), Passampa (PS), Siwa (SW), and Barangmamase (BM) between May and July 2024. Various environmental parameters, including nutrients, were measured. Phytoplankton samples were collected by filtering seawater using a 25 μm plankton net and analyzed in the laboratory. Results: The dominant types of phytoplankton were found to be Bacteriastrum, Chaetoceros, Leptocylindrus, Rhizosolenia, Thalassionema, and Ceratium. All of them are classified as Non-HABs. The identified types of HABs include Pseudo-nitzschia, Dinophysis, Prorocentrum, Protoperidinium, and Oscillatoria. Orthophosphate and salinity are two environmental parameters that affect the occurrence of HABs. The proportion of HABs abundance was lower than that of non-HABs in all locations. An increase in the abundance of HABs was detected in two locations: SW and BM. Conclusion: Although the proportion of HABs is lower than that of Non-HABs, the increased abundance of HABs in some locations, such as SW and BM, indicates the potential for future blooms. Monitoring environmental parameters, especially orthophosphate and salinity, is critical to mitigating the impact of the development of HABs, which ultimately affects the ecosystem and human health in Bone Bay. This study emphasizes the importance of sustainable water management to maintain the balance of the ecosystem in the bay.

Introduction: Synanthropic mammals benefit from food and shelter provided by green urban areas. However, they frequently interact with predators such as dogs which may modify certain behaviours and their spatial distribution, compromising their survival. Objective: To determine the effect of feral dogs’ presence on mesopredator synanthropic mammal feeding patterns by analyzing the spatial distribution of three species, opossum (Didelphis marsupialis), ringtails (Bassariscus astutus), and gray fox (Urocyon cinereoargenteus) in a green urban area in Mexico. Methods: Camera traps and scent stations were used to record foraging patterns and spatial distribution. The habitat was characterized and correlated with duration and frequencies of synanthropic mammal feeding patterns and spatial distribution. Results: Opossums were recorded more frequently inside vegetation compared to other areas of the park, while dogs were recorded in grass-covered areas, on roads, and in recreation zones. Ringtails and gray foxes were recorded inside vegetation and in open spaces. Feeding patterns were not affected by the presence or absence of dogs. However, the presence of dogs affected opossum and gray fox vigilance frequency and was associated with habitat characteristics. Ringtail vigilance was affected by dog presence and habitat characteristics. Conclusion: The interaction between dogs and wildlife may generate species-specific behavioural responses, allowing some species to be tolerant of risk while others may show spatial and temporal segregation. Understanding the spatial distribution of dogs and their effect on wildlife inhabiting green urban areas will help to improve control-impact programs of dogs, reducing predation events and improving the welfare of mesopredator synanthropic mammals.

Introduction: Ex situ conservation is essential for the preservation of threatened species, such as the gray titi monkey (Oedipomidas leucopus), an endemic primate of Colombia that inhabits the Magdalena Medio region. Many individuals enter Wildlife Care and Assessment Centers (CAVs) for rehabilitation and eventual release; however, achieving this goal is not always feasible. Objective: To assess the population dynamics of the gray titi monkey in four wildlife CAVs located within the species’ endemic region in Colombia. Methods: Various factors related to the ex situ conservation of the species were analyzed in CAVs in Antioquia and Caldas, including annual intake frequency, mortality, and duration of stay in the center, among other characteristics. Results: Between 2009 and 2021, a total of 282 individuals were managed across the four CAVs (48.8 % males and 51.2 % females). The majority, based on age group, were adults (51.8 %), while juveniles, pre-juveniles, and neonates represented 20.9 %, 22.7 %, and 4.6 %, respectively. The municipalities with the highest intake numbers were Medellín (n = 68), followed by La Dorada (n = 25), Norcasia (n = 15), and Victoria (n = 12). Differences were observed in the duration of stay among individuals, with the longest stays recorded for those who remained in the centers or were released. Conclusion: The population dynamics of the gray titi monkey highlight the extended duration of stay for released individuals, suggesting a need to strengthen rehabilitation strategies for the species.

Introduction: Deposition of feces in the environment is a key behavior in the ecology of predator carnivores, which promotes behavioral changes in animals, influencing the ecology, abundance, and distribution of the species with which they coexist. Objective: To analyze whether jaguar feces are detected by other jaguars and mammal species and if they have behavioral effects. Methods: We recorded the behavior of jaguar (Panthera onca), puma (Puma concolor), mesocarnivores (Leopardus pardalis, Leopardus wiedii, Herpailurus yagouaroundi), and prey species using camera traps, at marked sites (with jaguar feces; n = 28) and control sites (without jaguar feces; n = 10). Using the records, we analyzed, for rainy and dry seasons: (1) the detection of jaguar feces by animals and (2) whether animals modify their exploration, remarking, vigilance and foraging behavior after detecting jaguar feces. Results: The detection of jaguar feces by jaguars and pumas was similar and the detection was higher in dry season. Regarding the behaviors analyzed, jaguars explored 15 times more and remarked 13 more times, marked sites than control sites. Pumas explored eight times more marked sites than control sites. Mesocarnivores explored marked sites 17 times more than control sites. Prey explored 41 times more and increased their vigilance 24 times more at marked sites compared to control sites times. Conclusions: Jaguar feces are detected by conspecifics and other mammal species, and they have behavioral effects on them. This can trigger changes in the abundance and distribution of populations and may be one of the ways that large predators shape ecosystems.