Linking plant composition and arthropod abundance to establish little bustard breeding requirements in pastureland dominated landscapes

Most research on steppe bird habitat selection has been focused on the effects of management regimes or vegetation structure. However, much less is known on how plant composition is related with steppe bird occurrence. We investigated microhabitat of little bustard territorial males and females during the nesting and chick-rearing season in areas with dominance of pastureland focusing on plant composition. We searched for relationships between preferred vegetation and arthropod abundance in order to identify the contribution of different vegetation typologies in providing essential trophic resources for the species. Surveys of little bustards were made using car and foot transects. Plant composition was obtained within a 50 × 50 cm square at four sampling replicates and arthropod availability was sampled using a sweep net. Statistical procedures were conducted in three steps: (1) analysis of variance was used to identify at univariate level the plant composition and arthropod variables that were significantly related with both male and female occurrence sites; (2) principal components analysis was performed using the variables with significant results at univariate level; (3) model averaging on generalized linear and mixed models was applied to evaluate the selection probability of each principal component. The species occurs in sites with high floristic richness and high abundance of Fabaceae species, although plant composition differs from male to female sites. These variables were found to be crucial to provide higher abundances of arthropods, notably of Acrididea, Formicidae and some groups of Coleoptera which are decisive for the selection of displaying or female breeding sites

Nematoxic effect of essential oils and their fractions against the pinewood nematode, Bursaphelenchus xylophilus

The pinewood nematode (PWN) Bursaphelenchus xylophilus is a highly pathogenic plant parasite that greatly affects pine forests. In Portugal, the most affected species is Pinus pinaster Aiton. Despite great efforts, since its fist detection in 1999, the PWN has spread through the country, including Madeira Island, having been recently detected in Spain [1,2]. Containing this pest is of the utmost importance for European pine forest safeguard. Since most synthetic chemicals used to control phytoparasites are toxic to humans and animals, and can accumulate in the soil and in food plants [3], in the present work, the nematoxic potential of over 80 essential oils (EOs), isolated from the Portuguese flora, were assessed against the PWN. EOs were isolated by hydrodistillation and analysed by GC and GC-MS [3]. EOs hydrocarbon and oxygen-containing fractions were obtained as in [4]. Direct-contact assays, adapted from [3], were performed by adding EOs/methanol stock-solutions to 50-100 mixed-stage PWN suspensions. After 24h in darkness, dead and live nematodes were counted under an inverted microscope. Assays were repeated at least 10 times in two series. Mortalities ≥96% were obtained with 2μL/mL of the EOs isolated from Cymbopogon citratus, Eucalyptus citriodora, Mentha arvensis, Origanum virens, Origanum vulgare, Ruta graveolens, Satureja montana, Syzygium aromaticum, Thymbra capitata, Thymus caespititius (carvacrol and/or thymol-rich), Thymus vulgaris and Thymus zygis. These EOs were further tested at 1, 0.5 and 0.25μL/mL. Minimum lethal concentrations (LC100) <0.4μL/mL, were obtained for the 2-undecanone-rich R. graveolens EO and the carvacrol and γ-terpinene-rich S. montana and T. capitata EOs. Assays with EO fractions revealed that the monoterpene-rich nematoxic EOs control PWN through their combined hydrocarbon and oxygen-containing fractions through additive and/or synergic relations. As complex mixtures of active components, EOs may prove to be effective nematoxic age nts

The importance of grazing regime in the provision of breeding habitat for grassland birds: The case of the endangered little bustard (Tetrax tetrax)

In Mediterranean dry grasslands, grazing by domestic animals is an important agricultural activity on dry grasslands. Several bird species occur in these grazed habitats and are now experiencing a near continuous decline. We investigated the impact of livestock grazing on the threatened little bustard (Tetrax tetrax L.). The study was conducted at the NATURA 2000 Site/Important Bird Area of Cabrela, Portugal. Our main goals were to investigate responses of little bustard territorial males and breeding females to different livestock management practices, namely pasture types, stocking rates and sward structure. Bird distribution was surveyed using car and foot surveys. Data on grazing was supplied by land managers every 10 days from February to June through field interviews. Generalised additive models and model averaging were used to compute predictive models. Results indicate that higher probabilities of occurrence were found in long-term pastures and under light-moderate grazing conditions (stocking rates around 0.4 LU/ha). Conversely, lower probabilities of occurrence were found in ungrazed or heavy grazed fields. Males occurred mostly in large fields, but this variable seemed to be less important for females. On the other hand, green plant cover and the vegetation height were good predictors for the occurrence of females but not for males. Females used mostly pastures with vegetation height around 20–25 cm. Our results suggest that grazing management plans that aim to conserve little bustard populations should consider (1) the maintenance of the larger long-term pastures and (2) the use of light-moderate stocking rates (0.2–0.6 LU/ha)

A evolução do défice tarifário em Portugal

Segundo as previsões da Entidade Reguladora dos Serviços Energéticos (ERSE), o défice tarifário deverá atingir em finais do 2013 um valor acumulado de 3,7 mil milhões de Euros. Na comunicação social, o défice tarifário (DT) é considerado como mais uma “renda” a alguns grupos de interesse. Na realidade o DT é justificado por uma acumulação sucessiva de diversos tipos de sobrecustos do sistema elétrico que não foi considerada nas tarifas e preços da eletricidade nos anos anteriores aos respetivos consumidores elétricos. O trabalho aqui apresentado corresponde a uma primeira tentativa de analisar as razões políticas e económicofinanceiras para a existência do défice tarifário. Nesse sentido serão abordadas: as origens e justificações dos diferentes sobrecustos (CAE’s, CMEC’s, Garantia de Potência, Produção em Regime geral (PRE), convergência tarifária com as regiões autónomas dos Açores (RAA) e da Madeira (RAM), entre outros); a análise dos diferentes tipos de mecanismos; os parâmetros no cálculo dos sobrecustos bem como as possíveis soluções e medidas já implementadas para reduzir os efeitos do défice tarifário nas tarifas nos consumidores

Aplicação da metodologia lean na área de linhas de montagem na GE Power Controls Portugal

Tese de mestrado integrado. Engenharia Mecânica. Faculdade de Engenharia. Universidade do Porto. 201