Tree community variation in a tropical continental island according to slope aspect and human interference

ABSTRACT Associating description of unrecorded tropical tree community structure to sampling approaches that can help determine mechanisms behind floristic variation is important to further the comprehension of how plant species coexist at tropical forests. Thus, this study had the goals of (i) evaluating tree community structure on the continental island of Marambaia (23°4’37.09”S; 43°59’2.15”W) and (ii) testing the prediction that there are local scale changes in a tropical tree community structure between slopes facing different geographic orientation and with distinct human interference history. We established 60 (0.6 ha) sampling units in three different slope sites with distinct predominant geographic orientation and human interference. We sampled all woody trees with diameter at breast height (dbh) ≥ 5 cm. We found a total of 1.170 individuals representing 220 species, 120 genera and 50 families. The overall tree community structure and structural descriptors (abundance of individuals, basal area, species richness and diversity) varied extensively between the sites. The evidence presented here supports that local scale topography variations and human interference history can be important factors contributing to the known floristic heterogeneity of the Atlantic Rainforest. Future work on the study area should focus on disentangling effects from distinct causal factors over tree community variation and species occurrence

History and evolution of the arctic flora: in the footsteps of Eric Hultén

A major contribution to our initial understanding of the origin, history and biogeography of the present-day arctic flora was made by Eric Hulten in his landmark book Outline of the History of Arctic and Boreal Biota during the Quarternary Period, published in 1937. Here we review recent molecular and fossil evidence that has tested some of Hulten's proposals. There is now excellent fossil, molecular and phytogeographical evidence to support Hulten's proposal that Beringia was a major northern refugium for arctic plants throughout the Quaternary. In contrast, most molecular evidence fails to support his proposal that contemporary east and west Atlantic populations of circumarctic and amphi-Atlantic species have been separated throughout the Quaternary. In fact, populations of these species from opposite sides of the Atlantic are normally genetically very similar, thus the North Atlantic does not appear to have been a strong barrier to their dispersal during the Quaternary. Hulten made no detailed proposals on mechanisms of speciation in the Arctic; however, molecular studies have confirmed that many arctic plants are allopolyploid, and some of them most probably originated during the Holocene. Recurrent formation of polyploids from differentiated diploid or more low-ploid populations provides one explanation for the intriguing taxonomic complexity of the arctic flora, also noted by Hulten. In addition, population fragmentation during glacial periods may have lead to the formation of new sibling species at the diploid level. Despite the progress made since Hulten wrote his book, there remain large gaps in our knowledge of the history of the arctic flora, especially about the origins of the founding stocks of this flora which first appeared in the Arctic at the end of the Pliocene (approximately 3 Ma). Comprehensive analyses of the molecular phylogeography of arctic taxa and their relatives together with detailed fossil studies are required to fill these gaps.</p

Visual representations in crime prevention: exploring the use of building information modelling (BIM) to investigate burglary and crime prevention through environmental design (CPTED)

© 2018 Macmillan Publishers Ltd., part of Springer Nature Criminological research has long utilized visual representations of environments in seeking to explore perceptions of crime and personal safety and to investigate the relevance of specific design and security features. Much of this research has been in the field of environmental psychology and crime prevention through environmental design (CPTED). This paper traces the development of visual representations and the use of environmental stimuli in criminological research. We briefly review the contributions made by various visual media, including maps and drawings, photographs, models, video, virtual reality and gaming engines. These developments in visualization, building design and management technology have drastically improved the realism of representations of environments, and the potential for more standardized, widespread exploration and application of CPTED principles to reduce crime. To scope and evaluate the future potential of such emergent technologies, we critically review the literature concerned with virtual reality and building information technology (BIM), outlining uses in practice and new opportunities for criminological research. We frame the discussion with specific focus on analysing proposed residential dwellings to reduce vulnerability to burglary. A layered exploration for how BIM technologies may assist in implementing increasingly sophisticated assessments of crime vulnerability for proposed residential building designs brings the paper to a close. These discussions provide both a comprehensive overview for interested practitioners and chart specific opportunities for further research