El Gran Intercambio Biótico Americano: una revisión paleoambiental de evidencias aportadas por mamíferos y aves neotropicales

The resource‐use hypothesis, proposed by E.S. Vrba, states that habitat fragmentation caused by climatic oscillations would affect particularly biome specialists (species inhabiting only one biome), which might show higher speciation and extinction rates than biome generalists. If true, lineages would accumulate biome‐specialist species. This effect would be particularly exacerbated for biomes located at the periphery of the global climatic conditions, namely, biomes that have high/low precipitation and high/low temperature such as rainforest (warm‐humid), desert (warm‐dry), steppe (cold‐dry) and tundra (cold‐humid). Here, we test these hypotheses in swallowtail butterflies, a clade with more than 570 species, covering all the continents but Antarctica, and all climatic conditions. Swallowtail butterflies are among the most studied insects, and they are a model group for evolutionary biology and ecology studies. Continental macroecological rules are normally tested using vertebrates, this means that there are fewer examples exploring terrestrial invertebrate patterns at global scale. Here, we compiled a large Geographic Information System database on swallowtail butterflies' distribution maps and used the most complete time‐calibrated phylogeny to quantify diversification rates (DRs). In this paper, we aim to answer the following questions: (1) Are there more biome‐specialist swallowtail butterflies than biome generalists? (2) Is DR related to biome specialization? (3) If so, do swallowtail butterflies inhabiting extreme biomes show higher DRs? (4) What is the effect of species distribution area? Our results showed that swallowtail family presents a great number of biome specialists which showed substantially higher DRs compared to generalists. We also found that biome specialists are unevenly distributed across biomes. Overall, our results are consistent with the resource‐use hypothesis, species climatic niche and biome fragmentation as key factors promoting isolation.

Trophic niche breadth plays a key role in biogeographic distribution patterns. Theory posits that generalist strategies are favoured in a more heterogeneous set of environments across a spatio-temporal gradient of resources predictability, conferring individuals and species a greater capacity for colonising new habitats and thus expanding their distribution area. Using the family Falconidae (Aves, Falconiformes) as a model study, we tested the prediction that those species with a wider diet spectrum will have larger geographic range sizes and inhabit more biomes. We assessed the relationships between trophic breadth (diet richness and diversity) at different taxonomic resolutions of the prey (class and order), range size and biomic specialisation index (BSI; number of biomes inhabited) for the different species. Despite different diet breadth indexes and taxonomic resolutions defined differently the trophic niche of the clade and species, our findings revealed that trophic breadth was not a good predictor for range size but was for total environmental heterogeneity, with more diet-generalist species occupying a higher number of biomes. Diet breadth at the order taxonomic level showed a higher capacity of predicting BSI than at class level, and can be an important ecological trait explaining biogeographic patterns of the species.

Despite its current low diversity, the penguin clade (Sphenisciformes) is one of the groups of birds with the most complete fossil record. Likewise, from the evolutionary point of view, it is an interesting group given the adaptations developed for marine life and the extreme climatic occupation capacity that some species have shown. In the present contribution, we reviewed and integrated all of the geographical and phylogenetic information available, together with an exhaustive and updated review of the fossil record, to establish and propose a biogeographic scenario that allows the spatial-temporal reconstruction of the evolutionary history of the Sphenisciformes, discussing our results and those obtained by other authors. This allowed us to understand how some abiotic processes are responsible for the patterns of diversity evidenced both in modern and past lineages. Thus, using the BioGeoBEARS methodology for biogeographic estimation, we were able to reconstruct the biogeographical patterns for the entire group based on the most complete Bayesian phylogeny of the total evidence. As a result, a New Zealand origin for the Sphenisciformes during the late Cretaceous and early Paleocene is indicated, with subsequent dispersal and expansion across Antarctica and southern South America. During the Eocene, there was a remarkable diversification of species and ecological niches in Antarctica, probably associated with the more temperate climatic conditions in the Southern Hemisphere. A wide morphological variability might have developed at the beginning of the Paleogene diversification. During the Oligocene, with the trends towards the freezing of Antarctica and the generalized cooling of the Neogene, there was a turnover that led to the survival (in New Zealand) of the ancestors of the crown Sphenisciform lineages. Later these expanded and diversified across the Southern Hemisphere, strongly linked to the climatic and oceanographic processes of the Miocene. Finally, it should be noted that the Antarctic recolonization and its hostile climatic conditions occurred in some modern lineages during the Pleistocene, possibly due to exaptations that made possible the repeated dispersion through cold waters during the Cenozoic, also allowing the necessary adaptations to live in the tundra during the glaciations.

The purpose of this research was to understand the level of environmental knowledge among students at Santiago de Cali University (USC) and to evaluate the differences found based on school, gender, and age groups. To gather data, a survey that included sociodemographic information, aspects of environmental knowledge, actions aimed at mitigating environmental problems, and environmental awareness was administered to 268 students at USC in the year 2017. We conducted an online survey of 268 students in the year 2017 by means of a questionnaire that included 18 questions with sociodemographic information, aspects of environmental knowledge, actions aimed at mitigating environmental problems, and environmental awareness campaigns conducted at USC. Additionally, we conducted an analysis to assess how gender, age groups, and academic training influence the scores of the constructed indicators: General Index of Environmental Knowledge (GI), Identification of Environmental Problems (EP), Solutions to Environmental Problems (SP), and Knowledge of Environmental Campaigns (EC). Statistical tests (i.e., Mann–Whitney U test, Chi-square test of independence, Pearson’s coefficients correlation) were used to analyze the data. Through this study, we concluded that although no significant differences were found in environmental knowledge and actions to mitigate environmental problems between genders, age groups, and schools, there were important implications observed in these categories concerning the variables analyzed. In addition, positive correlations were found between the indicators GI and SP, both globally and at the level of each gender, age group, and in some schools, which shows that with greater knowledge of environmental problems, there is greater recognition of solutions.

The Proboscidea were very prominent in South American ecosystems during the Pleistocene and part of the Holocene. Specifically, in Valle del Cauca (Colombia), fossils of these large mammals have been found, reflecting an abundant presence in the region. In this work, a mandibular fragment with a complete last molar (m3) is reported, found near the bed of the Cauca River, in the Juanchito municipality of Santiago de Cali. According to the morphological features of the specimen, it is proposed that the remains belong to the proboscidean Notiomastodon platensis. This study emphasizes the large geographical distribution of this proboscidean in South America, including the Valle del Cauca, and provides new information on its presence in Colombia. In a paleoecological context, this work supports a generalist condition based on the use of food resources associated with the tropical dry forest during the processes of glacial and interglacial fluctuation that this type of ecosystem experienced during the Pleistocene epoch and that led to various changes in habitat aridity, fragmentation, and heterogeneity. Keywords: Notiomastodon, Quaternary, paleoecology, megafauna, South America.