22 research outputs found

    Annual cycles are the most common reproductive strategy in African tropical tree communities

    Get PDF
    We present the first cross continental comparison of the flowering and fruiting phenology of tropical forests across Africa. Flowering events of 5,446 trees from 196 species across 12 sites, and fruiting events of 4,595 trees from 191 species, across 11 sites were monitored over periods of 6 to 29 years, and analysed to describe phenology at the continental level. To study phenology we used Fourier analysis to identify the dominant cycles of flowering and fruiting for each individual tree and we identified the time of year African trees bloom and bear fruit and their relationship to local seasonality. Reproductive strategies were diverse and no single regular cycle was found in >50% of individuals across all 12 sites. Additionally, we found annual flowering and fruiting cycles to be the most common. Sub-annual cycles were the next most common for flowering whereas supra-annual patterns were the next most common for fruiting. We also identify variation in different subsets of species, with species exhibiting mainly annual cycles most common in West and West-Central African tropical forests, while more species at sites in East-Central and Eastern African forests showed cycles ranging from sub-annual to supra-annual. Despite many trees showing strong seasonality, at most sites some flowering and fruiting occurred all year round. Environmental factors with annual cycles are likely to be important drivers of seasonal periodicity in trees across Africa, but proximate triggers are unlikely to be constant across the continen

    Statistical model for earthquake economic loss estimation using GDP and DPI: a case study from Iran

    No full text
    As earthquakes can result in multi-dimensional negative consequences such as human loss and building damage, the ability to make accurate economic loss estimations immediately after the occurrence is crucial. Unfortunately, in many earthquake-stricken countries such as Iran, governments are often unable to quickly or accurately assess post-earthquake losses. The aim of this paper, therefore, is to extend the model developed by Chan et al. (Nat Hazards 17:269–283, 1998) to two independent variables to develop an earthquake economic loss estimation method based on the economic and socio-economic indices gross domestic product (GDP) and disposable personal income (DPI) and a seismic hazard probability function. A global cell map is also considered to assess the GDP and DPI based on the population in each cell affected by the earthquake. In the final stage, using the Modified Mercalli Intensity Scale, 18 earthquake damaged areas in Iran are taken as case study to estimate the economic losses using the new model presented in this paper
    corecore