Suchergebnisse

In southern Brazil, forests colonise grasslands only at a slow rate. Successional pathways and mechanisms are little known. Of selected pioneer woody species, I studied a) seedling emergence, survival and growth, and elder individual regenerative ability - experimentally, b) population structure and short-term dynamics - in permanent plots -, comparing grazed/burnt and abandoned grassland. The study elucidates several factors governing forest expansion: 1) Relative importance of seed and safe site limitation, seedling emergence rate and timing. 2) Factors influencing seedling survival and growth. 3) Relative importance of clonal spread and generative reproduction and relative performance of root suckers and seedlings in forest tree establishment. 4) Relative ability of forest trees and grassland shrubs to persist under recurrent disturbance. 5) Inhibition versus faciliation of forest tree establishment by grass and shrub communities and consequences of sudden shrub dieback.

AbstractThe mitigation of metals contamination is currently a crucial issue for the reclamation of mine sites. Indeed, mine wastes are often disposed in open dumps and consequently pollutants are subjected to dispersion in the surrounding areas. In this study, the potential use ofHelichrysum microphyllumsubsp.tyrrhenicumfor phytostabilization was evaluated in ex situ conditions. Ninety specimens were randomly selected and were planted in three substrates (reference substrate, mine waste materials, and mine wastes with compost). Mineralogical compositions of substrates, rhizosphere, and roots were assessed through X-ray diffraction (XRD). Zn, Pb, and Cd concentrations of substrates, rhizosphere, soil pore waters, and plant tissues were determined. The phytostabilization potential was determined through the application of biological accumulation coefficient (BAC), biological concentration factor (BCF), and translocation factor (TF). Moreover, survival and biometric parameters were assessed on plant specimens. The polluted substrates and related rhizosphere materials were mainly composed of dolomite, quartz, pyrite, and phyllosilicate. Zn was the most abundant metal in substrates, rhizosphere, and soil pore waters. XRD analysis on roots showed the presence of amorphous cellulose and quartz and Zn was the most abundant metal in plant tissues.H. microphyllumsubsp.tyrrhenicumrestricts the accumulation of the metals into roots limiting their translocation in aereal parts, indicating its potential use as phytostabilizer (BCF, BAC, TF < 1). Survival and growth data showed a great adaptability to different substrates, with an evident positive effect of the implementation of compost which increased the plant survival and decreased the metals uptake into roots.

The myrmicine ant genus Cardiocondyla consists of around 80 species of small, inconspicuous ants, which live mainly in subtropical and tropical Africa, Eurasia, and Australia. Several species have been accidentally introduced to America and have also invaded numerous originally ant-free islands around the world. The diversity of life histories in this genus, with lethally fighting wingless males, dominance hierarchies among queens, and considerable variation in the sociogenetic organization of colonies across species, has made it an interesting model to investigate the evolution and behavioral ecology of reproductive strategies. Taxa of the African Cardiocondyla shuckardi group are of particular interest, as in a phylogeny they lie between facultatively polygynous species with fatal male competition and monogynous species with mutually tolerant males. Studies on male behavior and sociogenetics in C. "venustula," a widespread member of the C. shuckardi group, showed that males defend small territories inside their subterraneous nests. At the same time, they revealed a surprisingly large variability in mtDNA haplotypes both within and between populations in South Africa, Angola, and Côte d'Ivoire. As the different lineages are very similar in morphology and nuclear markers, more research is needed to clarify the very confused taxonomic situation in this fascinating group of ants.

The Vale do Ribeira region has a large extension of Brazilian Atlantic Forest, and in most cities, low environmental impact activities predominate, such as sand mining. Sand mining has been trying to adapt their industrial activities to low environmental impact, aiming at the protection of permanent preservation areas (PPAs) of riparian forests. The objective of this work was to conduct a case study focused on monitoring and initial growth of forest species by 18 months. This study was performed in a riparian forest site on the Ribeira de Iguape River, Registro, state of São Paulo, Brazil, in a PPA with extraction of river bed sand. Forest species height, stem diameter and mortality index, and rainfall were evaluated in the period. Non-pioneer species accounted for 42.7 % of the forest, while pioneer species accounted for 53.1 %. These proportions are in accordance with local legislation, which establishes a lower limit of 40 % in planting for both groups. Drought periods and leaf-cutting ants at the beginning of growth stages contributed to a higher mortality index and irregular development of some species, however, even during such adversities, forest species indicated resistance to these conditions. Pioneer species had more important development, with emphasis onSenna multijuga,Alchornea triplinervia,Citharexylum myrianthumandTrema micranta, these species must be taken into consideration during the first stages of a project which aims at recovering degraded areas in riparian forests of Atlantic Forest. ; La región de Vale do Ribeira tiene una gran extensión de selva Atlántica brasileña, y en la mayoría de las ciudades predominan las actividades de bajo impacto ambiental, como la minería de arena de río. La extracción de arena ha estado tratando de adecuar sus actividades con menor impacto ambiental, apuntando a la protección de áreas de preservación permanente (APP). El objetivo fue realizar un estudio de caso con enfoque en el monitoreo y crecimiento inicial de especies forestales hasta 18 meses. Este ...

Major factors in biological and social systems -- Resource and technology -- Production : a mathematical theory -- Languages and cultures : an economic analysis -- The entropy theory of mind -- The entropy theory of value : a mathematical theory -- Epilogue : pioneer species and climax species.

Most studies on multi-use concepts of aquaculture and wind farms explored cultivation feasibility of extractive species, such as seaweed or bivalves. However, recent studies also included the cultivation of crustaceans or fish culture in the vicinity of wind turbines. Consequently, new approaches combine fed and extractive species in integrated multi-trophic aquaculture (IMTA) concepts for offshore multi-use to reduce nutrient output and the overall environmental impact of aquaculture operations. In this chapter the findings of a series of mussel and oyster cultivation experiments over several seasons are presented, which were conducted at different offshore test sites in the German Bight. Sites were selected within future offshore wind farm areas for an explicit multi-use perspective. Results have demonstrated successful growth and fitness parameters of these candidates and therefore definitely proved the suitability of these bivalve extractive species for open ocean aquaculture. Another approach for multi-use in offshore wind farms is its use as marine protected area or even for reinforcement or restoration of endangered species, which need the absence of any fisheries activity for recovery. Current projects are testing this perspective for the native European oyster Ostrea edulis and the European lobster Homarus gammarus. From the technological point of view there are many options on how to connect aquaculture devices, such as longline and ring structures as well as different cage types, to the foundations as well as to install it in the centre of the free area between wind turbines. Next to the system design also experiments on drag forces originating from the aquaculture structure on the foundation and vice versa were investigated. Complementary to the biological, environmental end technical aspects, a number of studies were specifically targeted to address and include stakeholders, their attitudes, their interests and concerns over time. By this approach, the inclusion of stakeholders into the research process from its very beginning until today, co-production of knowledge could be fostered. Next to joint identification of the major impediments and concerns of offshore aquaculture under multi-use conditions, new issues and research questions were identified. Primary focus on the economic potential of aquaculture in offshore wind farms was shown for consumption mussels. The production of mussels using longline technology is sufficiently profitable even under the assumption of substantial cost increases. This is especially true, if existing capacities could be used. Last but not least, the EEZ is a special area-it is not a state territory even if a coastal state has its sovereign rights and jurisdiction. It is an area where three legal systems come together: International law, law of the European Union and national law. There are no mariculture projects in the German EEZ and no approval procedure has been completed so far. Some sites are not suitable for mariculture, especially because of nature conservation and shipping.

Species composition and ecology of the epiphytic lichens collected on 31 species of the trees and shrubs at the rural settlements and their surrounding area were studied. In total 71 lichens species including 25 species on the fruit and berry crops were found. On many trees, even in forests the variety of species of lichens is strongly depleted. This is especially true for rural settlements, razing places, keeping and running cattle. Bryoria and Usnea species at the rural settlements and their surrounding area were not found. It was shown that G. scripta is a pioneer species on the speckled alder under the conditions of relatively strong shading and humidity.