Florian Hofhansl

Tropical Ecosystem Research


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Beta diversity and oligarchic dominance in the tropical forests of Southern Costa Rica

Our article entitled “Beta diversity and oligarchic dominance in the tropical forests of Southern Costa Rica” was recently published in the journal Biotropica doi.org/10.1111/btp.12638.

Forest community assembly is shaped by environmental factors and stochastic processes, but so far the contribution of oligarchic species to the variation of community composition (i.e., beta diversity) remains poorly known. We established 1‐ha permanent inventory plots in humid lowland tropical forests of southwestern Costa Rica to identify oligarch species characterizing changes in community composition among forest types. Based on this network of forest plots we investigate how community composition responds to differences in topography, successional stage, and distance among plots for different groups of species (all, oligarch, common and rare/very rare species). From a total of 485 species of trees, lianas and palms recorded in this study only 27 species (i.e., 6%) were nominated as oligarch species. Oligarch species accounted for 37% of all recorded individuals and were present in at least half of the plots. Plant community composition significantly differed among forest types, thus contributing to beta diversity at the landscape scale. Oligarch species was the component best explained by geographical and topographic variables, allowing a confident characterization of the beta diversity among tropical lowland forest stands.

Please see this link to the online version of the article.


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Terrestrial light detection and ranging for estimating tropical vegetation biomass

Our article entitled “Performance of Laser-Based Electronic Devices for Structural Analysis of Amazonian Terra-Firme Forests” was recently published in the section “Remote Sensing Techniques for Precision Forestry” a special issue of the journal Remote Sensing (Remote Sens. 2019, 11(5), 510; doi: 10.3390/rs11050510)

Novel in situ remote sensing techniques may provide nondestructive alternative approaches to derive biomass estimates for tropical forest ecosystems. We report error metrics for measurements of tree diameter and tree height and show that estimates of aboveground biomass are in good agreement (<10% measurement uncertainty) with traditional measurements. We quantify total and systematic errors among measurements obtained from laser-based electronic devices and conclude that terrestrial light detection and ranging (LiDAR) can complement conventional measurement techniques, thus improving biomass estimates for tropical forest ecosystems.

Please see the article “Performance of laser-based electronic devices for structural analysis of Amazonian terra-firme forests” submitted to Special Issue “Remote Sensing Techniques for Precision Forestry”


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Biologische Globalisierung bedroht entlegene Inseln

Anzahl an Neobiota auf Inseln steigt mit der Entfernung zum Festland

Je weiter eine Insel vom Festland entfernt ist, desto weniger heimische Tier- und Pflanzenarten, aber desto mehr vom Menschen eingeschleppte Arten – sogenannte Neobiota – beherbergt sie. Zu diesem überraschenden Ergebnis kommt ein internationales Forschungsteam vom Department für Botanik und Biodiversitätsforschung der Universität Wien in der aktuellen Ausgabe der renommierten Fachzeitschrift “PNAS”.

Blick auf die malerischen Rainbow Falls nahe der Stadt Hilo auf Big Island/Hawaii. Alle Pflanzen in unmittelbarer Umgebung sind nicht-heimisch (© Holger Kreft).

Weiterlesen auf dem Blogeintrag zum press release der Universität Wien


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Upcoming below-ground field-campaign

We have still limited understanding of the mechanisms that shape the immense functional diversity and species richness of plants in tropical ecosystems. Such knowledge gaps hinder our ability to evaluate the impact that deforestation and soil degradation may have on forest regeneration and soil conservation. Our goal in this study is to highlight the importance of belowground processes in maintaining crucial ecosystem functions by investigating relationships among evolutionary phylogeny, morphological and physiological root traits and mycorrhizal associations in relation to soil nutrient availability in an integrated framework.

Overview

We aim to create the first curated collection of fine roots from tropical systems that will be accessible via an online library to the scientific community as well as to the general public. We therefore expect that this investigation will fill an important gap in root ecology by providing invaluable information about (1) how tropical trees are able to maintain efficient nutrient acquisition, (2) root functional traits present in tropical areas, and (3) resulting implications for management of forest regeneration and soil degradation under future scenarios.

Check out the video of the campaign here