13 research outputs found

    Recovery of logged forest fragments in a human-modified tropical landscape during the 2015-16 El Nino

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    The past 40 years in Southeast Asia have seen about 50% of lowland rainforests converted to oil palm and other plantations, and much of the remaining forest heavily logged. Little is known about how fragmentation influences recovery and whether climate change will hamper restoration. Here, we use repeat airborne LiDAR surveys spanning the hot and dry 2015-16 El Nino Southern Oscillation event to measure canopy height growth across 3,300ha of regenerating tropical forests spanning a logging intensity gradient in Malaysian Borneo. We show that the drought led to increased leaf shedding and branch fall. Short forest, regenerating after heavy logging, continued to grow despite higher evaporative demand, except when it was located close to oil palm plantations. Edge effects from the plantations extended over 300 metres into the forests. Forest growth on hilltops and slopes was particularly impacted by the combination of fragmentation and drought, but even riparian forests located within 40m of oil palm plantations lost canopy height during the drought. Our results suggest that small patches of logged forest within plantation landscapes will be slow to recover, particularly as ENSO events are becoming more frequent. It is unclear whether tropical forest fragments within plantation landscapes are resilient to drought. Here the authors analyse LiDAR and ground-based data from the 2015-16 El Nino event across a logging intensity gradient in Borneo. Although regenerating forests continued to grow, canopy height near oil palm plantations decreased, and a strong edge effect extended up to at least 300m away.Peer reviewe

    Vitality assessment of Prague Energy Company, Inc..

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    The thesis is focused on application of methods of financial analysis, solvent and bankruptcy indicators and methods for assessing the vitality of the company by H. Pollak. These methods will be applied on the Prague Energy Company, Inc. This thesis aims to compare the resulting values and vitality assessment of Prague Energy Company, Inc

    Finanční analýza společnosti STOCK Plzeň a.s.

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    Finanční analýza společnosti STOCK Plzeň a.s, skládá se z teoretické a praktické části, řešeny funkce a metody finanční analýzy, srovnáná s odvětvím. Cílem práce je komplexní posouzení finanční situace společnosti. Užito období let 2000 - 200

    Finanční analýza společnosti STOCK Plzeň a.s.

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    Finanční analýza společnosti STOCK Plzeň a.s, skládá se z teoretické a praktické části, řešeny funkce a metody finanční analýzy, srovnáná s odvětvím. Cílem práce je komplexní posouzení finanční situace společnosti. Užito období let 2000 - 200

    Vliv dračince rumělkového (Dracaena cinnabari) jako "nurse plant" na diverzitu cévnatých rostlin

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    Dracaena cinnabari, the dominant endemic tree of Socotra Island (Yemen), is in serious decline. The effect this will have on the island's plant diversity remains unknown. This dissertation aimed to assess the possible role of Dracaena as a nurse plant by identifying plants associated with Dracaena understorey and by assessing the importance of Dracaena for maintaining plant diversity. In the first part of the dissertation, relevés sampled in Dracaena understorey and in open sites to record the number of individuals of vascular plants were analysed. Species richness and composition were compared between understorey and open sites, and species associated with each of these habitats were identified. Additionally, the effects of shading and leaf litter on species richness and abundance were analysed. The second part of dissertation focused on mature woody species composition of Dracaena stands and investigated spatial relations between Dracaenas and other mature woody plants. The last part of the dissertation aimed to assess the fine scale spatial relationships between stones and plants in Dracaena stands and evaluated the differences of these relationships between understorey and open sites. The results confirmed the Dracaena role as an important nurse plant. The tree enhances the environmental heterogeneity and its presence creates two distinct microhabitats (understorey and open sites). The understorey habitat, compared with open site, harbours higher number of species, including endemics. The species in Dracaena stands can be classified as either understorey specialists, open-site specialists or generalists. The decline of Dracaena will negatively affect plant diversity, will reduce abundance of rare endemic plants and will lead to homogenization of vegetation. As no other tree species exists which could replace the Dracaena, our findings underline the importance of conservation efforts to preserve Dracaena stands on Socotra and identify this species as a key umbrella species whose conservation would ensure also the protection of a number of other associated species

    Two new species of Thismia subsect. Odoardoa (Thismiaceae) from Borneo

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    Background – Two new species of the sect. Thismia subsect. Odoardoa, Thismia cornuta Hroneš, Sochor & Dančák and Thismia pallida Hroneš, Dančák & Rejžek, from Malaysian Borneo are described and illustrated. The former species is distributed in the Bario area of the Kelabit Highlands of Sarawak, and the latter occurs in the SAFE (Stability of Altered Forest Ecosystem) Project area, northwest of Tawau in Sabah.Methods – This study is based on field observations in several forest localities in Sarawak and Sabah and herbarium material deposited in SAN, SAR and OL. Both conventional herbarium techniques and comparison with protologues of described species were applied.Results – Thismia cornuta is morphologically closely related to T. inconspicua Sochor & Dančák from Brunei Darussalam and T. chrysops Ridl. from the Malay Peninsula but it differs from both species by the presence of only two appendages at apical margin of the connective, by horn-like projection on each side of the lateral appendage and by white colour of perianth tube. It was found at three localities and is preliminarily treated as endangered (EN). Thismia pallida is morphologically close to T. filiformis Chantanaorr. from Thailand but differs by the presence of five appendages at apical margin of connective, by box-shaped lateral appendage exceeding apex of connective and by shorter filiform appendage of perianth lobe. It was found at a single locality within twice logged secondary forest and it is preliminarily treated as critically endangered (CR). This is only the second record of Thismia species inhabiting secondary forests in tropical Asia

    Two new species of Thismia subsect. Odoardoa (Thismiaceae) from Borneo

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    Background – Two new species of the sect. Thismia subsect. Odoardoa, Thismia cornuta Hroneš, Sochor & Dančák and Thismia pallida Hroneš, Dančák & Rejžek, from Malaysian Borneo are described and illustrated. The former species is distributed in the Bario area of the Kelabit Highlands of Sarawak, and the latter occurs in the SAFE (Stability of Altered Forest Ecosystem) Project area, northwest of Tawau in Sabah.Methods – This study is based on field observations in several forest localities in Sarawak and Sabah and herbarium material deposited in SAN, SAR and OL. Both conventional herbarium techniques and comparison with protologues of described species were applied.Results – Thismia cornuta is morphologically closely related to T. inconspicua Sochor & Dančák from Brunei Darussalam and T. chrysops Ridl. from the Malay Peninsula but it differs from both species by the presence of only two appendages at apical margin of the connective, by horn-like projection on each side of the lateral appendage and by white colour of perianth tube. It was found at three localities and is preliminarily treated as endangered (EN). Thismia pallida is morphologically close to T. filiformis Chantanaorr. from Thailand but differs by the presence of five appendages at apical margin of connective, by box-shaped lateral appendage exceeding apex of connective and by shorter filiform appendage of perianth lobe. It was found at a single locality within twice logged secondary forest and it is preliminarily treated as critically endangered (CR). This is only the second record of Thismia species inhabiting secondary forests in tropical Asia

    To chop or not to chop? Tackling shrub encroachment by roller-chopping preserves woody plant diversity and composition in a dry subtropical forest

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    Shrub encroachment is a frequently observed phenomenon in the arid and semi-arid biomes. In the dry forests of the Argentine Chaco ecoregion that are affected by shrub encroachment, the growing demand for grazing areas has led to the creation of a silvopastoral system. Under the Chaco silvopastoral system, a commonly used treatment to disrupt the excessive shrub layer and promote the growth of grasses is roller-chopping by a tractor-pulled iron drum. While previous studies evaluating the effects of roller-chopping on diversity have focused mostly on the herbaceous stratum as the primary source of forage, much less is known about the effects of roller-chopping on woody plants. To fill this gap, we measured woody plants of the shrub layer in a low-intensity roller-chopping experiment in northern Argentina after applying different frequencies of roller-chopping in a semi-arid Chaco forest area with a well-developed shrub layer. Data were collected in an experiment in which 3 different roller-chopping treatments were applied: a single two-pass roller-chopping in the summer of 2006/2007 (RCh1); a one-pass roller-chopping in the summer of 2006/2007, repeated in the summer of 2014/2015 (RCh2); and no treatment (Control). In each treatment, 16 circular, randomly placed plots with a radius of 9 m were sampled, and all woody plants in the shrub layer with a diameter ≥10 mm at the base were recorded. The diversity was analysed using profiles of alpha and beta diversity and by calculating the average distance from an individual circular plot to the treatment group centroid defined in the principal coordinate space. In total, 26 species of woody plants were recorded, of which 24 were found in Control, 22 in RCh1, and 23 in RCh2. Although the alpha diversity differed only slightly among the treatments, the beta diversity of the roller-chopped treatment areas was generally higher than that of the untreated plots. The species composition of the roller-chopped plots differed little from that of the control plots. Our study revealed little overall effect of roller-chopping on the species diversity and composition of woody plants. The transformation of the Chaco forest degraded by shrub encroachment to a silvopastoral system by roller-chopping is changing the structure of the forest but to a large extent has retained the presence and the relative abundance of woody plant species. We conclude that roller-chopping is a good management tool to reduce woody plant encroachment and create a silvopastoral system while preserving ecosystem functions.EEA Santiago del EsteroFil: Rejžek, Martin. Mendel University in Brno. Faculty of Forestry and Wood Technology. Department of Forest Botany, Dendrology and Geobiocoenology; República ChecaFil: Coria, Ruben Dario. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santiago del Estero; ArgentinaFil: Kunst, Carlos Roberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santiago del Estero; ArgentinaFil: Svátek, Martin. Mendel University in Brno. Faculty of Forestry and Wood Technology. Department of Forest Botany, Dendrology and Geobiocoenology; República ChecaFil: Kvasnica, Jakub. Mendel University in Brno. Faculty of Forestry and Wood Technology. Department of Forest Botany, Dendrology and Geobiocoenology; República ChecaFil: Navall, Jorge Marcelo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santiago del Estero; ArgentinaFil: Ledesma, Roxana Ramona. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santiago del Estero; ArgentinaFil: Gomez, Adriana Teresita. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santiago del Estero; ArgentinaFil: Matula, Radim. Mendel University in Brno. Faculty of Forestry and Wood Technology. Department of Forest Botany, Dendrology and Geobiocoenology; República Chec

    Sustainable Land Use Management Needed to Conserve the Dragon’s Blood Tree of Socotra Island, a Vulnerable Endemic Umbrella Species

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    Unsustainable overgrazing is one of the most important threats to the endemic and endangered population of dragon’s blood tree (Dracaena cinnabari) on Socotra Island (Republic of Yemen). However, there is a lack of information about the exact population size and its conservation status. We estimated the population size of D. cinnabari using remote sensing data. The age structure was inferred using a relationship between crown projection area and the number of branch sections. The conservation importance of each sub-population was assessed using a specially developed index. Finally, the future population development (extinction time) was predicted using population matrices. The total population size estimated consists of 80,134 individuals with sub-populations varying from 14 to 32,196 individuals, with an extinction time ranging from 31 to 564 years. Community forestry controlled by a local certification system is suggested as a sustainable land management approach providing traditional and new benefits and enabling the reforestation of endemic tree species on Socotra Island
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