Search results for "ecological"

Phytoplankton distribution along trophic gradients within and among reservoirs in Catalonia (Spain)

2008

SUMMARY 1. Longitudinal gradients in the epilimnetic waters of stratified reservoirs provide a useful database to study changing environmental conditions. The spatial distribution, assemblage structure and specific adaptations of phytoplankton assemblages can be analysed along these gradients over short time scales. 2. Four reservoirs with a similar typology, located along an altitudinal gradient in the same eco-region, were sampled along their longitudinal axes. In total, 19 sampling stations provided a trophic spectrum, ranging from oligo-mesotrophy to hypertrophy, which was quantified by calculating the trophic state index of each sampling station in the four reservoirs. 3. Several patte…

Early plant succession in two abandoned cut-over peatland areas

1990

Initial stages of plant succession (from 0 to 8 or 9 yr) were studied on abandoned peat harvest sites of two adjacent areas in Finland. At the Mustasuo area only 13 field layer species, all perennials, and 3 ground layer species became established during that period and species composition stayed relatively constant. All species occurred sparsely with low biomass. The Riitasuo area was colonized by 43 field layer and 19 ground layer species during the first 8 yr of succession. In that area the originally plantless sites were totally covered by plants within a few years. Many of the first species to arrive were annuals, most of which were soon replaced by perennial species. The great differe…

Enchytraeid population dynamics: Resource limitation and size-dependent mortality

2009

Abstract Enchytraeids are regarded as keystone soil organisms in forest ecosystems. Their abundance and biomass fluctuate widely. Predicting the consequences of anthropogenic disturbances requires an understanding of the mechanisms underlying enchytraeid population dynamics. Here I develop a simple model, which predicts that the type of dynamics is controlled by resource input rate. If fungal resource input is a discrete event once a year, an exponential growth phase is followed by starvation and sharp decline of enchytraeid abundance. Model simulations with three different forcing functions were compared to field data. Initial parameter values were obtained from various independent sources…

Multivariate analysis of sites using water invertebrates and land use as indicators of the quality of biotopes of Mediterranean relic plant (Petagnae…

2007

Petagnaea gussonei is a rhizomatous, perennial scapose hemicryptophyte species belonging to a monospecific genus of Apiaceae. It lives only along woodland rivulets and is a Tertiary relic localized in the restricted area of the Nebrodi Mountains (NE Sicily, Italy). Ecological indicators have been employed to understand the status of eight localities (intermittent rivulets) where the species occurs. In order to evaluate both the rivulets' water-quality and landscape use, index of anthropisation (Ia), water fleas bioassay (TU), and analyses of water macroinvertebrates have been employed. The results obtained for the level of toxicity exclude the presence of macropollutants (TU < 0.001), where…

Civic resielience : botanical gardens in North America, birth, development, and enviromental awarness

2023

The chapter explores from a historical perspective the birth of botanical gardens in North America, considered a significant part of the ecological network system and of the green and blue 'infrastructure'. This important system opposes geographical risk, which must be organically dealt with in programmes, plans and strategies that protect the landscape, prevent risks, and strengthen short-, medium- and long-term actions, also involving local Communities, integrating the vision to the different scales of intervention and projects. The Botanical Garden, seen here as an 'Open Work', has an important role not only because it preserves botanical specimens that come from all over the world, but …

An ecological model of bridging the digital divide in education: A case study of OLPC deployment in Nepal

2018

Combination of ozonation and photocatalysis for purification of aqueous effluents containing formic acid as probe pollutant and bromide ion

2014

The treatment by advanced oxidation processes (AOPs) of waters contaminated by organic pollutants and containing also innocuous bromide ions may generate bromate ions as a co-product. In the present work heterogeneous photocatalysis and ozonation have individually been applied and in combination (integrated process) to degrade the organic compounds in water containing also bromide anions. The results show that: i) the sole photocatalysis does not produce bromate ions and in the case of its presence, it is able to reduce bromate to innocuous bromide ions; ii) the integration of photocatalysis and ozonation synergistically enhances the oxidation capabilities; and iii) in the integrated proces…

La teoria ecològica del desenvolupament: un marc teòric per a la comprensió del comportament humà

2008

L'any 2009 es van complir 30 anys de la publicació del llibre The Ecology of Human Development d'Urie Bronfenbrenner (1917-2005). Aquesta obra va signifi car la síntesi del pensament d'aquest autor, que ja havia esbossat en textos anteriors, i el punt de referència d'una teoria estimulant sobre el comportament humà. La idea bàsica de Bronfenbrenner és que el desenvolupament de l'individu es troba condicionat per les característiques dels entorns en què té lloc, és a dir, l'ésser humà es «fa» en interacció dinàmica amb els seus contextos i en el marc de les relacions entre aquests. Malgrat la rellevància teòrica i metodològica d'aquesta aportació, continua resultant poc coneguda per a una ma…

Creative City Reloaded. Ecological Planning for the Changing Times

2012

Abitiamo, lavoriamo e ci muoviamo nella Urban Age, ed iI successo della città come forma prevalente dell’abitare non solo le assegna il ruolo di growth machine dello sviluppo, motore dell’evoluzione e del dinamismo delle comunità, ma la carica anche della responsabilità di essere un modello positivo - oltre che vincente - generatore di stili di vita innovativi, più sostenibili, intelligenti e creativi. Le città si propongono come potenti attrattrici della popolazione non solo dalle zone rurali, ma – con maggiore vigore in epoca di crisi – anche da altre città, intra-regionali o addirittura trans-nazionali, ed il flusso di capitale sociale che le attraversa può alimentarne la rigenerazione e…

Bacteria Associated with Copestylum (Diptera, Syrphidae) Larvae and Their Cactus Host Isolatocereus dumortieri

2011

We describe the gut bacterial diversity inhabiting two saprophagous syrphids and their breeding substrate (decayed tissues of the columnar cactus Isolatocereus dumortieri). We analyzed the gut microbiota of Copestylum latum (scooping larvae that feed on decayed cactus tissues) and Copestylum limbipenne (whose larvae can also feed on semiliquid tissues) using molecular techniques. DNA was extracted from larval guts and cactus tissues. The V1-V3 region of the 16S rRNA genes was amplified and sequenced. A total of 31079 sequences were obtained. The main findings are: C. limbipenne is dominated by several Enterobacteriaceae, including putative nitrogen-fixing genera and pectinolitic species and…