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Background: Defining Andean anurans through their altitudinal limits has been a common practice in species lists, studies of responses to climate change among others, especially in the northern Andes. At least three proposals to differentiate Andean anurans from lowland anurans through elevation and at least one to differentiate Andean anurans from high mountain anurans have been formulated. However, the most frequently used altitudinal limits are not based on theoretical or numerical support, but on observations or practical definitions. Additionally, these proposals have been applied equally to different portions of the Andes, ignoring the fact that even between slopes of the same mountain, environmental conditions (and therefore the distribution of species) may differ. The objective of this work was to evaluate the concordance between the altitudinal distribution of anurans in the Colombian Andes and four different altitudinal delimitation proposals. Methods: We constructed our study area in a manner that allowed us to include species from the Andean region (as traditionally defined) and adjacent lowlands, because if the boundaries criteria were applied they would separate the species of the latter by themselves. We divided the study area into eight entities according to the watershed and the course of the most important rivers. We conducted a bibliographic search for all anurans in the cordilleras and inter-Andean valleys of Colombia and complemented the search with information on anurans for the region available in the GBIF. After curing the species distribution points, we generated elevation bands of 200 m amplitude for both the study area and for each Andean entity. Subsequently, we performed a cluster analysis to evaluate the grouping of the elevation bands according to their species composition. Results: In none of the cases (neither for the entire study area nor for any of the entities) we found a correspondence of any of the traditionally used boundaries and the altitudinal distribution of Anurans in the Andean region of Colombia. Instead, on average, the altitudinal delimitation proposals arbitrarily spanned the altitudinal distribution of about one third of the species distributed in the study area. Conclusions: We suggest that, although, based on our results, some Andean entities can be divided according to the altitudinal composition of the species that occur in them, we did not find any results that support the idea of a generalizable altitudinal limit for the Colombian Andes. Thus, to avoid biases in studies that may later be used by decision makers, the selection of anuran species in studies in the Colombian Andes should be based on biogeographic, phylogenetic or natural history criteria and not on altitudinal limits as they have been used.
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Ríos , Colombia , FilogeniaRESUMEN
As primarily sessile organisms, plants often show a non-random spatial distribution of genotypes over distance. This process known as fine-scale spatial genetic structure (FSGS) has been suggested through systematic reviews to depend on life form, mating system, and pollen and seed dispersal vectors, while there is no consensus on its behaviour due to external factors, such as anthropogenic habitat changes. By conducting a systematic review and global meta-analysis of empirical FSGS studies, we aimed to evaluate how anthropogenic habitat fragmentation and degradation influence the strength of FSGS in plant populations by means of the Sp statistic. Moreover, we tested how pollination and seed dispersal vectors contribute to the variation of the Sp statistic. We retrieved 243 FSGS studies from 1960 to 2020 of which only 65 were informative for the systematic review. Most empirical studies comprised outcrossers (84%) and trees (67%), with few herbs (23%) and scarce annual species (2%). In weighted meta-analyses for 116 plant populations (31 studies), we did not detect significant effects in the magnitude of effect sizes for the Sp statistic among undisturbed, degraded and fragmented habitats. Results showed significant effects for seed dispersal vectors, but not for pollination. Overall, we observed high variation among the effect sizes (not related to the goodness-of-fit of mixed models) of habitat status, pollination and seed dispersal categories, which precludes identifying biological trends on the Sp statistic. More empirical studies are needed that contrast multiple plant populations in disturbed versus undisturbed habitats, and by increasing the taxonomic groups, such as herbs and annual plants.
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Background: Xicotli data is the short name given to the dataset generated within the project framework "Integration of Biodiversity Data for the Management and Conservation of Wild Bee-Plant Interactions in Mexico (2021-2023)", as xicotli is the generic word for a bee in Nahuatl. The team comprised eco-informaticians, ecologists and taxonomists of both native bees and flora. The generated dataset contains so far 4,532 curated records of the plants, which are potential hosts of species of three focal families of bees native to Mexico: Apidae, Halictidae and Megachilidae and morphological and ecological data of the plant-bee interactions. This dataset was integrated and mobilised from citizen observations available at naturalista.mx (iNat), which were compiled through the iNaturalist project. New information: The new information obtained with the Xicotli data project was: Taxonomic information about bee species curated by taxonomists based on the information contained in iNaturalist;Taxonomic identification of the host plants by a botanist from the photos compiled by the Xicotli Data project;Data on the ecomorphological traits of bees and plants based on expert knowledge and literature. All the data were integrated into the Xicotli Data Project via the creation of new "observation fields". The visibility of the information originally contained in iNaturalist was maximized and can be consulted directly on the iNaturalist platform.
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BACKGROUND: Mining, agriculture and cattle production are activities that threaten the quality and quantity of water resources in the Colombian Andes. However, many drainage basins in this region have not been subjected to simultaneous evaluation of the impact these activities have on the density, diversity and composition of aquatic macroinvertebrates (AMI). The first two of these ecological variables are expected to decrease drastically from zones with no apparent impact towards areas with anthropogenic activity, which areas with mining will present the most impoverished AMI community. METHODS: We evaluated the density, diversity and composition dissimilarity of AMI in streams impacted by gold mining, agriculture and cattle production. Two reference streams were also studied. Six benthic samplings were conducted bimonthly (Feb 2014-Feb 2015) using a Surber net. Water samples were taken in order to make environmental evaluation among the aforementioned streams, including hydrological, physicochemical and bacteriological parameters (HPCB). Diversity was evaluated as the effective number of RTUs-recognizable taxonomic units-by comparing the richness, typical diversity, and effective number of the most abundant RTUs. Compositional dissimilarity was examined with nMDS and CCA analysis. RESULTS: A total of 7,483 organisms were collected: 14 orders, 42 families and 71 RTUs. Our prediction regarding the density and diversity of AMI (Reference > Cattle production > Agriculture > Mining) was partially fulfilled, since the agriculture-dominated stream presented a more impoverished AMI community than that of the gold mining stream. However, these streams presented lower diversity than the cattle production and reference streams, and the AMI density only differed significantly between one reference stream and the agriculture stream. The AMI composition in the agriculture-dominated stream clearly differed from that of the other streams. DISCUSSION: The observation of a more impoverished AMI community in agricultural production areas compared to those with mining or cattle production may reflect the importance of the remaining riparian vegetation, which was scarce at the stream with agricultural activity. Moreover, the low diversity, and mainly the reduced AMI richness, in the agriculture stream coincided with the absence of insect genera are intolerant to deterioration of the biological and physicochemical conditions of the water (e.g. Anacroneuria). CONCLUSIONS: The results suggest that the local impact of agricultural activities may be of equal or greater magnitude than that of mining in terms of AMI density, diversity and composition, in the Colombian Andean riverscape. Future studies should systematically evaluate, throughout the annual cycle, the relative effects of the productive land use, the remaining native vegetation cover and the consequent changes in the HPCB parameters of the water on AMI communities in Colombian Andean basins.
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Population studies are essential for understanding different aspects of species' biology, estimating extinction probability, and determining evolutionary and life history. Using the mark-recapture method, we studied the abundance and population structure of dung beetle species (Deltochilum mexicanum and Dichotomius satanas) over one year in a human-modified landscape in Mexico. We captured 1960 individuals with a net recapture rate of 11%. Deltochilum mexicanum had a higher rate of recapture (14%) than Dichotomius satanas (5%). Annual variation in abundance was similar for both species, with maximum abundance occurring in summer and a marked reduction during winter. Deltochilum mexicanum was dominant inside the forest, and its abundance was influenced by vegetation cover, temperature, and humidity. Dichotomius satanas was more frequent outside the forest, and none of the considered environmental variables affected its abundance. The adult sex ratio of Deltochilum mexicanum was female-biased, whereas that of Dichotomius satanas was male-biased. The maximum estimated population size was similar for both species, but Deltochilum mexicanum had a higher number of new individuals and survival rate. Since species with different biological attributes presented a similar pattern of abundance and population structure, we conclude that environmental conditions are the main regulator of dung beetle populations in the human-modified landscape.
