Annual dynamics of nutrients in a temporary stream in Southern Portugal: contributions of the primary producers and the drainage basin

Under the Mediterranean climatic conditions, the annual precipitation distribution determines that many streams are temporary with surface flow interruption during the summer dry period in contrast to the high discharges during floods, observed from late autumn to early spring. As water flows through the drainage basin it can pick up nutrients, sediments and pollutions. These can affect the ecological processes causing eutrophication where primary producers’ growth is accelerated. In this study, the nutrient (N and P) concentrations were determined in water and river sediments, over a 3 years period in a 3rd order temporary stream reach of 500 m (Pardiela stream in Guadiana basin). The nutrients concentration in the water and in the sediment shows a decrease during the flood events due to the high discharge, followed by a rapid increase, although the nutrients concentrations in the sediments were smaller than in the water. The primary producers were studied during the same 3 years period, in terms of biomass of macrophytes, periphyton, and leaves fall in order to describe the annual patters. Complementary, a rapid assessment of N, P and C concentration in macrophytes was analyzed with the objective to determine their nutrients contribution to the system in summer (1047.35 g/m2) although with low contents of P, N and C. Periphyton represents a basal contribution of biomass to the system, with high levels along the year, decreasing immediately after flood events and increasing subsequently. Contrary to what is described for the north hemisphere, in this study the leaves start to fall at the end of spring as surface flow decreases. The maximum leaves fall coincides with the maximum stream contraction at the end of summer, contributing to a high stream bed detritus biomass accumulation (143 g/m2). The highest nutrient input to the system comes from the drainage basin, especially after the flood events which also lead 3 weeks later to an increase in macrophyte biomass. The global results obtained in this study give a contribution to understanding the underlying processes in a temporay Mediterranean system which is a key issue to determine flexible and adaptive ecological management, promoting the conservation of natural ecosystems under global changes conditions

Review on the major ecosystem impacts caused by damming and watershed development in an Iberian basin (SW-Europe): focus on the Guadiana estuary

The Guadiana estuary (Iberian Peninsula, Europe) hits low agriculture, industry and urban pressure, unlike other major Iberian estuaries; however, this situation is about to change. The Alqueva dam was constructed at 150 kill from the river mouth, creating one of the biggest artificial lakes in Europe, which will support 110 000 ha of irrigation areas. Moreover, the estuarine margins are suffering increased human pressure. The risks that the Alqueva darn will pose to the downstream ecosystems, mainly to the estuary and adjacent coastal area, will be reviewed in this paper. Other issues are also analysed, as increased human desertification in the Portuguese basin, real estate pressure and the impact of the construction of a public infrastructure in the Portuguese lower estuary. Increased problems of sediment load reduction, water quality deterioration and shifts in the downstream fish populations are expected due to higher river flow reduction. Irreversible changes to estuarine margins and increased risk Of Pollution in the estuary will result from the multiple urban pressures. Lack of forest management and increased risk of wildfires, leading to water quality degradation and increased soil erosion. are a result of human desertification in the upper Portuguese basin. Multiple solutions to tackle these problems have to be considered. Creating the International Natural Park of the Lower Guadiana Would not he enough and tourism should not be regarded as the only way to develop such a poor region. An ecohydrological approach of the basin should be implemented, to establish scientific based solutions to help solving conflicts and testing scenarios. Ultimately, the creation of a Portuguese-Spanish Basin Management Council for the lower Guadiana, involving those that are interested in the sustainable development of the Guadiana (local populations and associations, private stakeholders (darn managers, tourism entrepreneurs, farmers), local and national authorities, ENGO's and scientists) is essential to produce ecological and sustainable management decisions

Biotic and abiotic interactions in temporary summer pools of southern Portugal

In the south of Portugal, the summer season is characterized by reduced precipitation and high air temperatures, which causes the disruption of surface flow and subsequent formation of disconnect pools that may dry out entirely. During this dry period, there is a natural decrease of water quality standards due to the lack of water, leaving temporary rivers very vulnerable. Nevertheless, the remaining pools and surroundings become important in the survival of biological communities. Aquatic macroinvertebrates were sampled in several pools during the summer period (in the beginning and before the ending), in temporary tributaries of the Degebe River (Guadiana catchment), to quantify the response of macroinvertebrates communities to seasonal desiccation and habitat fragmentation. It we collected thousands individuals, representing 27 families of macroinvertebrates. Changes in the composition and abundance were affected by temporal variability in pool volume and location in the watershed. Smaller, upstream pools showed less diversity and abundance than downstream pools. Higher biological interactions and higher level of relationships with terrestrial ecosystems were perceptible for smaller summer pools. Pools were typically dominated by tolerant taxa such as midge larvae (Chironomidae), lesser boatman (Corixidae) and Oligochaeta, resulting in low diversity of communities over time. The results indicated the importance and impact of changes in habitat quality, size and connectivity in aquatic macroinvertebrates communities. They also revealed the importance of preservation and conservation of temporary ecosystems, particularly during the dry season, when the anthropogenic interference in ecosystems is more evident and can jeopardize the biodiversity maintenance of these systems

Merging traditional livelihood activities with new employment opportunities brought by ecotourism to Iona national park, Angola: rethinking social sustainability

Ecotourism activities and investment projects have been consistently increasing worldwide over the last few decades. In this process, ecotourism has contributed to fight poverty, to create local employment opportunities and to promote nature conservation. However, there are also plenty examples of nature-base tourism destinations where ecotourism principles have been distorted and negative impacts are on the rise. Therefore, studies that provide a deep understanding of the roots and consequences of those both positive and negative impacts are needed to achieve new higher tourism quality standards, to foster a sound local development and to promote an integrated and sustainable national growth. To obtain information useful to contribute specific recommendations aimed at linking tourism employers and job seekers, we have conducted a survey addressing locals’ demographic characteristics and their engagement in traditional livelihood activities. Data gathered from 202 respondents showed that in the largest villages traditional livelihood activities, excepting pastoralism, tend to have little expression while the same activities seem to play a key role in some small communities. Striking differences were found between nomadic or semi-nomadic people and people who have been assimilated into the western civilization and also have more sedentary life styles. Using this information and taking in consideration some new employment opportunities brought nature-based tourism to the Iona National Park, we have identified specific demographic profiles more suited for part-time and full-time jobs

The transatlantic introduction of weakfish Cynoscion regalis (Bloch & Schneider, 1801) (Sciaenidae, Pisces) into Europe

Weakfish Cynoscion regalis (Bloch and Schneider, 1801) is a sciaenid fish native to the east coast of North America and has been recently collected in three areas of the Iberian Peninsula (Europe). We aimed to i) provide the first report of the presence of weakfish in Europe, ii) hypothesize the most likely introduction vector, iii) discuss the potential for ecological overlap between weakfish and meagre Argyrosomus regius (Asso, 1801), the native Sciaenidae species, and iv) highlight the importance of citizen science in the detection of nonnative species. Weakfish were captured in the Sado estuary (July 2014), Gulf of Cadiz (November 2015) and the adjacent Guadiana estuary (June 2016), and in two Galician Rías (June 2016). Anglers reported that weakfish was present in the Sado estuary for “some” years, while their presence was only noticed recently in the other two areas. We hypothesize that ballast water was the introduction vector, that weakfish established a reproducing population in the non-native range, and that it dispersed from the Sado estuary, a central region of its current distribution range. The Sado estuary might have been the introduction area for weakfish via ballast water because there is a busy transoceanic commercial port in the estuary. Moreover, they are not used in European aquaculture facilities, nor in the aquarium trade. The collected specimens were ≤50 cm, with average lengths of 30 cm, which corresponds to a median age of 2 years and to individuals capable of reproducing. As a result, the year of introduction must be before 2012. Weakfish have a similar ecological niche to meagre, but the outcome of potential interactions is uncertain. Citizen science, especially the initiative of local fishermen, was critical to detect this non-native species.info:eu-repo/semantics/publishedVersio

O quarteirão na cidade de Lisboa: da forma ao tipo

O tecido urbano, tanto na sua componente pública como privada, traduz o esforço paralelo de tensão e mudança, de transformação e permanência, que caracteriza a cidade. Este processo dinâmico de produção urbana reflete-se na evolução permanente da forma e organização do quarteirão enquanto elemento intermediário entre a função de habitação e as outras actividades urbanas. A investigação procura realizar um estudo da forma urbana da cidade de Lisboa a partir da sua componente privada, expressa na leitura do quarteirão, unidade básica do tecido edificado e do parcelário e suporte da dinâmica que o configura. Para tal, pretende-se abordar este elemento no seu estado actual como resultado de um processo evolutivo, servindo como princípio para um estudo tipo-morfológico. O trabalho utilizará como objecto de estudo a cidade de Lisboa a partir de 12 casos escolhidos, representativos da sua diversidade.The urban fabric, both in his public and private component, translates the parallel stress of tension and change, transformation and permanence, which characterize the space and architecture that builds the city. This dynamic process of urban production is reflected in the continuing evolution of the shape and organization of the urban block as an intermediary between the housing function and other urban activities. The research seeks to undertake a study of the urban form in Lisbon from its private component, expressed in the study of the block, the built fabric basic unit and the plots the support of dynamic that configures it. To this end, we intend to place this element in its current state as a result of an evolutionary process, serving as a principle for a typo-morphological study.Peer Reviewe