Morphologic variability of the Acer campestre L. populations in Bosnia and Herzegovina

Morphologic variability from 25 populations of Acer campestre L. in Bosnia and Herzegovina was analyzed. Morphometric structure of variability and between-population variability was performed based on 10 fruit-parameter characteristics and 19 leaf-parameter characteristics using multivariate statistical analysis. Results confirmed the separation of three submediterranean populations as a group in relation to other tested populations, from which the Banja Luka population is different. Measured leaf parameters were confirmed as a predominant carrier of the morphologic separation between populations. In other Acer species populations within A. monspessulanum and A. intermedium species are separated mainly by fruit and much less by leaf parameters. The southernmost submediterranean populations from Trebinje, Ljubuški, and Mostar regions have smaller leaf areas, which consequently places them within the same morphologic group; their variability is in tight connection with eco-geo-graphical factors, where the ecological distance is a much better predictor of morphological variability compared to geographical distance. The air temperature had the biggest influence on morphological variability regarding the highest in-between correlation. Achieved results may serve for the continuation of the research in other areas of Acer campestre to determine the interactive effect of ecological, geographical, climatic, and migrational factors on their morphologic population plasticity.

Leaps and bounds: geographical and ecological distance constrained the colonisation of the Afrotemperate by Erica

Background The coincidence of long distance dispersal (LDD) and biome shift is assumed to be the result of a multifaceted interplay between geographical distance and ecological suitability of source and sink areas. Here, we test the influence of these factors on the dispersal history of the flowering plant genus Erica (Ericaceae) across the Afrotemperate. We quantify similarity of Erica climate niches per biogeographic area using direct observations of species, and test various colonisation scenarios while estimating ancestral areas for the Erica clade using parametric biogeographic model testing. Results We infer that the overall dispersal history of Erica across the Afrotemperate is the result of infrequent colonisation limited by geographic proximity and niche similarity. However, the Drakensberg Mountains represent a colonisation sink, rather than acting as a “stepping stone” between more distant and ecologically dissimilar Cape and Tropical African regions. Strikingly, the most dramatic examples of species radiations in Erica were the result of single unique dispersals over longer distances between ecologically dissimilar areas, contradicting the rule of phylogenetic biome conservatism. Conclusions These results highlight the roles of geographical and ecological distance in limiting LDD, but also the importance of rare biome shifts, in which a unique dispersal event fuels evolutionary radiation.

Leaps and bounds: geographical and ecological distance constrained the colonisation of the Afrotemperate by Erica

The coincidence of long distance dispersal and biome shift is assumed to be the result of a multifaceted interplay between geographical distance and ecological suitability of source and sink areas. Here, we test the influence of these factors on the dispersal history of the flowering plant genus Erica (Ericaceae) across the Afrotemperate. We quantify similarity of Erica climate niches per biogeographic area using direct observations of species, and test various colonisation scenarios while estimating ancestral areas for the Erica clade using parametric biogeographic model testing. We infer that the overall dispersal history of Erica across the Afrotemperate is the result of infrequent colonisation limited by geographic proximity and niche similarity. However, the Drakensberg Mountains represent a colonisation sink, rather than acting as a “stepping stone” between more distant and ecologically dissimilar Cape and Tropical African regions. Strikingly, the most dramatic examples of species radiations in Erica were the result of single unique dispersals over longer distances between ecologically dissimilar areas, contradicting the rule of phylogenetic biome conservatism. These results highlight the importance of rare biome shifts, in which a unique dispersal event fuels evolutionary radiation.

Modelling beta diversity of aquatic macroinvertebrates in High Andean wetlands

<p>Central Andean Highlands represent a singular environment characterized by various extreme conditions. Among them, peatbogs are exceptional marshy habitats scattered throughout this arid and harsh area. In an effort to understand the patterns of beta diversity, we sampled the benthic macroinvertebrates of thirteen peatbogs and related the biological distance with ecological distance using the GDM (Generalized Dissimilarity Modelling) approach. Variables analyzed were altitude, geographical distance, physical and chemical parameters of the water. A coefficient based on the ordering properties of count data, from the perspective of both sites and taxa, was used to measure the compositional similarity between samples. The most frequent taxa were: <em>Hyallela</em>, Simuliidae, <em>Andesiops</em>, <em>Austrelmis</em>, Podonominae, <em>Protallagma</em>, <em>Trichocorixa</em>, Orthocladiinae and Glossiphonidae. The highest altitudinal record ever for leeches is reported here. Altitude and conductivity contributed greatly to the single ecological predictor of beta diversity. Sampling points can be classified first by altitude (cutoff sets at 4,200 m), which can be considered a surrogate of a regional factor (distinction between Puna and High Andean ecoregions) and then by conductivity (cutoff sets at 135 µS cm^-1), which can be considered a proxy of a local factor (distinction between hyperfresh and more mineralized habitats). These results suggest a system of ecological filters acting on them. </p>

Ecological niche structure and rangewide abundance patterns of species

Spatial abundance patterns across species' ranges have attracted intense attention in macroecology and biogeography. One key hypothesis has been that abundance declines with geographical distance from the range centre, but tests of this idea have shown that the effect may occur indeed only in a minority of cases. We explore an alternative hypothesis: that species' abundances decline with distance from the centroid of the species' habitable conditions in environmental space (the ecological niche). We demonstrate consistent negative abundance–ecological distance relationships across all 11 species analysed (turtles to wolves), and that relationships in environmental space are consistently stronger than relationships in geographical space.

Phylogenetic constraints on fine-scale patterns of habitat use by eight primate species in eastern Ecuador

Lowland forests of western Amazonia contain the most species-rich primate communities in the Neotropics, which begs the question of what mechanisms operate to promote species coexistence. This study examines habitat occupancy and its relationship to phylogeny in a primate community in Amazonian Ecuador. First, as potential factors that shape community structure, we determined whether (1) mean height in the forest canopy differed among species; (2) within each species, habitat occupancy was disproportional to habitat availability; and (3) species diverged in habitat occupancy. We then tested hypotheses regarding ecological distance and its relationship to phylogenetic distance among species pairs within this community. We tested these hypotheses primarily with data derived from 15 censuses of primate species on two 100-ha plots in eastern Ecuador. In these censuses, we observed eight primate species over nearly 200 encounters. We observed larger species at greater heights in the forest canopy than smaller ones. Although they occupied habitat types at frequencies proportionate to their availability in the study area, species diverged in habitat occupancy. Although a clear relationship was not observed between phylogenetic and ecological distances among species pairs, this study suggests that ecological differences among the species in this community facilitate their coexistence.