Site index model approach for drained peatland forest stands

Tiivistelmä: Pituusboniteettisovellus ojitusalueiden metsille

Comparison of thinning methods in a Scots pine stand on drained peatland : a simulation study

Tiivistelmä: Harvennusmenetelmien vertailu ojitetun turvemaan männikössä. Simulointitutkimus

Properties of slow-release phosphorus fertilizers with special references to their use on drained peatland forests : A review

Tiivistelmä: Hidasliukoisten fosforilannoitteiden ominaisuudet ja käyttökelpoisuus suometsien lannoituksessa. Kirjallisuuteen perustuva tarkastelu

Vegetation and CO2 balance in an abandoned harvested peatland in Aitoneva, southern Finland

Tiivistelmä: Kasvillisuus ja CO2-tase käytöstä vapautuneella turvetuotantoalueella Kihniön Aitonevalla

Ecology and evolution of social-organization: insights from fire ants and other highly eusocial insects

Social organisms exhibit conspicuous intraspecific variation in all facets of their social organization. A prominent example of such variation in the highly eusocial Hymenoptera is differences in the number of reproductive queens per colony, Differences in queen number in ants are associated with differences in a host of reproductive and social traits, including queen phenotype and breeding strategy, mode of colony reproduction, and pattern of sex allocation. We examine the causes and consequences of changes in colony queen number and associated traits using the fire ant Solenopsis invicta as a principal model. Ecological constraints on mode of colony founding may act as important selective forces causing the evolution of queen number in this and many other ants, with social organization generally perpetuated across generations by means of the social environment molding appropriate queen phenotypes and reproductive strategies. Shifts in colony queen number have profound effects on genetic structure within nests and may also influence genetic structure at higher levels (aggregations of nests or local demes) because of the association of queen number with particular mating and dispersal habits. Divergence of breeding habits between populations with different social organizations has the potential to promote genetic differentiation between these social variants. Thus, evolution of social organization can be important in generating intrinsic selective regimes that channel subsequent social evolution and in initiating the development of significant population genetic structure, including barriers to gene flow important in cladogenesis.

Intraspecific genetic variation in arbuscular mycorrhizal fungi and its consequences for molecular biology, ecology, and development of inoculum

It has been known for some time that different arbuscular mycorrhizal fungal (AMF) taxa confer differences in plant growth. Although genetic variation within AMF species has been given less attention, it could potentially be an ecologically important source of variation. Ongoing studies on variability in AMF genes within Glomus intraradices indicate that at least for some genes, such as the BiP gene, sequence variability can be high, even in coding regions. This suggests that genetic variation within an AMF may not be selectively neutral. This clearly needs to be investigated in more detail for other coding regions of AMF genomes. Similarly, studies on AMF population genetics indicate high genetic variation in AMF populations, and a considerable amount of variation seen in phenotypes in the population can be attributed to genetic differences among the fungi. The existence of high within-species genetic variation could have important consequences for how investigations on AMF gene expression and function are conducted. Furthermore, studies of within-species genetic variability and how it affects variation in plant growth will help to identify at what level of precision ecological studies should be conducted to identify AMF in plant roots in the field. A population genetic approach to studying AMF genetic variability can also be useful for inoculum development. By knowing the amount of genetic variability in an AMF population, the maximum and minimum numbers of spores that will contain a given amount of genetic diversity can be estimated. This could be particularly useful for developing inoculum with high adaptability to different environments.

Winter ecology of a female White-Backed Woodpecker Dendrocopos leucotos (Bechstein)

Summary

Pedological and isotopic relations of a highland tropical peatland, Mountain Range of the Espinhaço Meridional (Brazil)

The evolution of organic matter sources in soil is related to climate and vegetation dynamics in the past recorded in paleoenvironmental Quaternary deposits such as peatlands. For this reason, a Histosol of the mineralotrophic peatland from the Pau-de-Fruta Special Protection Area - SPA, Espinhaço Meridional, State of Minas Gerais, was described and characterized to evidence the soil constituent materials and properties as related to changes in environmental conditions, supported by the isotopic and elementary characterization of soil C and N and 14C ages. Samples were collected in a depression at 1,350 m asl, where Histosols are possibly more developed due to the great thickness (505 cm). Nowadays, the area is colonized by vegetation physiognomies of the Cerrado Biome, mainly rocky and wet fields (Campo Rupestre and Campo Úmido), aside from fragments of Semidecidual Seasonal Forest, called Capões forests. The results this study showed that early the genesis of the analyzed soil profile showed a high initial contribution of mostly herbaceous organic matter before 8,090 ± 30 years BP (14C age). In the lower-mid Holocene, between 8,090 ± 30 years AP (14C age) to ± 4,100 years BP (interpolated age), the vegetation gradually became more woody, with forest expansion, possibly due to increased humidity, suggesting the existence of a more woody Cerrado in the past than at present. Drier climate conditions than the current were concluded ± 2,500 years BP (interpolated age) and that after 430 years BP (14C age) the forest gave way to grassland, predominantly. After the dry season, humidity increased to the current conditions. Due to these climate fluctuations during the Holocene, three decomposition stages of organic matter were observed in the Histosols of this study, with prevalence of the most advanced (sapric), typical of a deposit in a highly advanced stage of pedogenetic evolution.

Water retention in a peatland with organic matter in different decomposition stages

Peatlands are ecosystems formed by successive pedogenetic processes, resulting in progressive accumulation of plant remains in the soil column under conditions that inhibit the activity of most microbial decomposers. In Diamantina, state of Minas Gerais, Brazil, a peatland is located at 1366 m asl, in a region with a quartz-rich lithology and characteristic wet grassland vegetation. For this study, the peat area was divided in 12 transects, from which a total of 90 soil samples were collected at a distance of 20 m from each other. The properties rubbed fiber content (RF), bulk density (Bd), mineral material (MM), organic matter (OM), moisture (Moi) and maximum water holding capacity (MWHC) were analyzed in all samples. From three selected profiles of this whole area, samples were collected every 27 cm from the soil surface down to a depth of 216 cm. In these samples, moisture was additionally determined at a pressure of 10 kPa (Moi10) or 1500 kPa (Moi1500), using Richards' extractor and soil organic matter was fractionated by standard procedures. The OM decomposition stage of this peat was found to increase with soil depth. Moi and MWHC were highest in layers with less advanced stages of OM decomposition. The humin levels were highest in layers in earlier stages of OM decomposition and with higher levels of water retention at MWHC and Moi10. Humic acid contents were higher in layers at an intermediate stage of decomposition of organic matter and with lowest levels of water retention at MWHC, Moi10 and Moi1500.

Effect of repeated fertilizer application on the nutrient status and biomass production of salix 'Aquatica' plantations on cut-away peatland areas

Summary

Mapping, organic matter mass and water volume of a peatland in Serra do Espinhaço Meridional

Peatlands form in areas where net primary of organic matter production exceeds losses due to the decomposition, leaching or disturbance. Due to their chemical and physical characteristics, bogs can influence water dynamics because they can store large volumes of water in the rainy season and gradually release this water during the other months of the year. In Diamantina, Minas Gerais, Brazil, a peatland in the environmental protection area of Pau-de-Fruta ensures the water supply of 40,000 inhabitants. The hypothesis of this study is that the peat bogs in Pau-de-Fruta act as an environment for carbon storage and a regulator of water flow in the Córrego das Pedras basin. The objective of this study was to estimate the water volume and organic matter mass in this peatland and to study the influence of this environment on the water flow in the Córrego das Pedras basin. The peatland was mapped using 57 transects, at intervals of 100 m. Along all transects, the depth of the peat bog, the Universal Transverse Mercator (UTM) coordinates and altitude were recorded every 20 m and used to calculate the area and volume of the peatland. The water volume was estimated, using a method developed in this study, and the mass of organic matter based on samples from 106 profiles. The peatland covered 81.7 hectares (ha), and stored 497,767 m³ of water, representing 83.7 % of the total volume of the peat bog. The total amount of organic matter (OM) was 45,148 t, corresponding to 552 t ha-1 of OM. The peat bog occupies 11.9 % of the area covered by the Córrego das Pedras basin and stores 77.6 % of the annual water surplus, thus controlling the water flow in the basin and consequently regulating the water course.