Opportunity identification competence : explaining individual and exploring team opportunity identification by employees
Baggen, Yvette - \ 2017
Wageningen University. Promotor(en): Martin Mulder, co-promotor(en): Harm Biemans; Thomas Lans. - Wageningen : Wageningen University - ISBN 9789462579682 - 182
entrepreneurship - professional competence - competences - education - businesses - small businesses - medium sized businesses - employment opportunities - netherlands - portugal - europe - ondernemerschap - vakbekwaamheid - bevoegdheden - onderwijs - bedrijven - kleine bedrijven - middelgrote bedrijven - kansen op werk - nederland - portugal - europa
Opportunities and their identification are of significant importance for competitiveness in today’s complex and turbulent business environment because they serve as a key influencing factor for new value-creation. Opportunity identification (OI) is interesting not only from the perspective of new business start-ups, but also from the perspective of employees in existing organisations. Each entrepreneurial process starts with an imagined, rudimentary idea in the mind of an individual. The further exploration and development of such opportunities by employees can lead to the realisation of all kinds of corporate entrepreneurship outcomes, such as innovation, strategic renewal, and internal or external venturing.
This dissertation reports on the capability of employees to identify opportunities, referred to as opportunity identification competence (OIC). The importance of OI by employees is widely recognised in practice, and scholars have contributed significantly to understanding what opportunities are, how opportunities come into being, and how OIC can be measured. Nevertheless, substantial research challenges still need to be addressed. More specifically, based on both entrepreneurship literature and literature on organisational learning and entrepreneurship education, three overarching research issues have been identified:
The OI process has not been fully mapped out, including the role of individuals and teams.
Defining and explaining OIC is problematic because scholars tend not to agree whether opportunities are discovered in the economic environment or created by individuals.Existing measurements of OIC have been criticised, because most of them include self-perceptions or the recall of earlier identified opportunities.
The main goal of this thesis was to contribute to the literature by addressing these three overarching research issues. Accordingly, the central research question was: What characterises opportunity identification by employees on the individual and team level?
In the dissertation, OIC is both conceptually mapped and empirically explored. A performance instrument to measure OIC is developed and tested in higher education. As well, 12 businesses, including 234 employees in 51 teams, participated in this research project. Most companies were in the category known as small and medium-sized enterprise (SME). The participating companies have in common that they felt an urgent need for entrepreneurship as a driver of competitiveness. Furthermore, they aimed to commit and stimulate their employees to contribute to the entrepreneurial process, without having formal mechanisms or structures for doing so.
In light of the central research question of this dissertation, What characterises opportunity identification by employees on the individual and team level?, the results suggest that OI deserves attention in existing businesses, both as a meaningful process leading towards new value-creation and as a relevant capability of employees. OIC is a multi-phased phenomenon consisting of two main competencies, namely business idea generation and business idea evaluation. In business idea generation, individuals generate all kinds of (business) ideas that may have the potential to become a real opportunity. In business idea evaluation, those ideas are selected that actually have potential success. Employees can have one of the competencies (business idea generation or business idea evaluation) to a greater extent, or both of them. Organisations need employees that are able to generate business ideas and employees that are able to evaluate the potential success of business ideas. The results of this thesis suggest that, just like independent entrepreneurs, employees mainly acquire such competencies by a process of learning by doing; this means that employees should become involved in entrepreneurial activities on the shop floor. Creating teams can be a solution, bringing together the competencies needed for the successful identification of opportunities. Moreover, the results suggest that the commitment of teams in the early stages of the entrepreneurial process is highly relevant, because the team cognitive framework for identifying opportunities seems more effective than the individual cognitive framework.
Taken together, at the defining, initial stage of the entrepreneurial process opportunities are identified by individuals or, preferably, by teams – in a process by which business ideas are generated and evaluated for their potential success. When studying opportunities and their identification, scholars should take into account the differences in OIC between SMEs, employees, and even within OIC itself (i.e., between business idea generation and business idea evaluation). In practice as well, these differences should be considered in the selection and management of employees, in assessing OIC and in composing teams, because teams need both business idea generators and business idea evaluators.
Evaluation of effects of agri-environmental measures on rangeland degradation in two less favoured areas in Portugal
Jones, N.M. - \ 2015
Wageningen University. Promotor(en): Leo Stroosnijder, co-promotor(en): Jan de Graaff; Luuk Fleskens. - Wageningen : Wageningen University - ISBN 9789462574618 - 154
agrarisch natuurbeheer - extensieve weiden - landdegradatie - milieuafbraak - landgebruik - bedrijfssystemen - portugal - agri-environment schemes - rangelands - land degradation - environmental degradation - land use - farming systems - portugal
Evaluation of effects of agri-environmental measures on rangeland degradation in two less-favoured areas in Portugal
Nadia Manuela Jones
In the past decades there have been significant land use changes in Portugal. After the integration of Portugal in the EU, farmers have been able to benefit from EU policy measures, which were initially mainly aimed at supporting farmer’s income. It soon became apparent that these land use changes led to both intensification and abandonment of land, which were detrimental to the environment in various ways, in particular to higher soil erosion hazards and to an increased incidence of wildfire.
The thesis assesses the impact of agro-environmental policies on agro-ecosystem goods and services and land degradation at farm and regional levels in Portugal. It identifies the main land use changes, provides insight in the role of past policy measures targeting the preservation of extensive grazing in marginal areas, and explores the options for the improvement of future policy measures.
First an historical review is provided of land use changes in Portugal and their implications for land degradation and conservation. Thereafter an analysis is made of the farming systems in two less favoured areas in Centro and Alentejo regions, which showed an increasing focus on livestock and rangeland activities. Subsequently an assessment is made of the role of two specific EU agri-environmental measures (AEM) that preserve extensive grazing in these two less-favoured areas in Portugal. Thereby attention is paid to the uptake of these AEMs and to their effects on preserving reduced stocking rates and sufficient soil cover. An analysis is also made of the AEM payments and other EU subsidy flows, and their changes over the period 2005-2009, and of the effectiveness of the financial incentives offered through the two specific AEMS for preserving extensive grazing in the two research areas. Finally a normative analysis is made, whereby the impact of agri-environmental policy is targeted. Through scenario analysis of different combinations of policy measures for the two research areas, the impacts on extensive livestock farm production, soil erosion risk and wildfire hazard are assessed. A final discussion about the respective research results is presented in the synthesis of the thesis.
Oral bioaccessibility and human exposure to anthropogenic and geogenic mercury in urban, industrial and mining areas
Rodrigues, S.M. ; Coelho, C. ; Cruz, N. ; Monteiro, R.J.R. ; Henriques, B. ; Duarte, A.C. ; Romkens, P.F.A.M. ; Pereira, E. - \ 2014
Science of the Total Environment 496 (2014). - ISSN 0048-9697 - p. 649 - 661.
atomic-absorption-spectrometry - potentially toxic elements - chloralkali plant - inorganic mercury - part i - contaminated soils - asturias spain - speciation - sediments - portugal
The objective of this study was to characterize the link between bioaccessibility and fractionation of mercury (Hg) in soils and to provide insight into human exposure to Hg due to inhalation of airborne soil particles and hand-to-mouth ingestion of Hg-bearing soil. Mercury in soils from mining, urban and industrial areas was fractionated in organometallic forms; mobile; semi-mobile; and non-mobile forms as well as HCl-extractable Hg. The in vitro bioaccessibility of Hg was obtained by extracting soils with (1) a simulated human gastric fluid (pH 1.5), and (2) a simulated human lung fluid (pH 7.4). Total soil Hg concentrations ranged from 0.72 to 1.8 mg kg- 1 (urban areas), 0.28 to 94 mg kg- 1 (industrial area) and 0.92 to 37 mg kg- 1 (mining areas). Both organometallic Hg as well as 0.1 M HCl extractable Hg were lower (<0.5% of total Hg) than Hg extracted by gastric fluid (up to 1.8% of total Hg) and lung fluid (up to 12% of total Hg). In addition, Hg extracted by lung fluid was significantly higher in urban and industrial soils (average 5.0–6.6% of total Hg) compared to mining soils. Such differences were related to levels of mobile Hg species in urban and industrial soils compared to mining soils. These results strengthen the need to measure site-specific Hg fractionation when determining Hg bioaccessibility. Results also show that ingestion and/or inhalation of Hg from soil particles can contribute up to 8% of adult total Hg intake when compared to total Hg intake via consumption of contaminated fish and animal products from contaminated areas.
Comparative analysis of policies to deal with wildfire risk
Carreiras, M. ; Ferreira, A.D.J. ; Valente, S. ; Fleskens, L. ; Gonzales-Pelayo, O. ; Rubio, J.L. ; Stoof, C.R. ; Coelho, C.O.A. ; Ferreira, C.S.S. ; Ritsema, C.J. - \ 2014
Land Degradation and Development 25 (2014)1. - ISSN 1085-3278 - p. 92 - 103.
public-participation - forest owners - fire regimes - management - portugal - perspective - examples - impacts - system - region
Fires are the main driver of land degradation in forest areas in Mediterranean sub-humid regions and are likely to increase as a result of climate and other global changes. To prevent deleterious processes induced by fire, several policies and strategies have been implemented at national and regional scales. We perform a comparative study of policies and strategies of Portuguese and Spanish (Comunitat Valenciana) cases in order to assess the differences between them and identify their roles in forest fire prevention and in combating and mitigating impacts. To this end, we analyse the sustainability objectives stated in the legislation of each country to identify the strategies used to deal with forest fires and the extent to which they are integrated to achieve the sustainability objectives they pursue. The comparative analysis includes an assessment of sustainability, evaluated by the explicitness of the objectives, and identification of how the lines of action contribute to reach these objectives. We found different levels of complexity and that the adoption or rejection of some of the techniques is closely related to the tradition and the experience of local communities. This analysis highlights the importance of local characteristics and the stakeholders, involvement in designing effective strategies to reduce fire risk
A detailed comparative study between chemical and bioactive properties of Ganoderma lucidum from different origins
Stojkovic, D.S. ; Barros, L. ; Calhelha, R.C. ; Glamoclija, J. ; Ciric, A. ; Griensven, L.J.L.D. van; Sokovic, M. ; Ferreira, I.C.F.R. - \ 2014
International Journal of Food Sciences and Nutrition 65 (2014)1. - ISSN 0963-7486 - p. 42 - 47.
medicinal mushrooms - antioxidant properties - wild mushrooms - liquid-chromatography - fruiting body - fr. karst - portugal - polysaccharides - molecules - nutrients
A detailed comparative study on chemical and bioactive properties of wild and cultivated Ganoderma lucidum from Serbia (GS) and China (GCN) was performed. This species was chosen because of its worldwide use as medicinal mushroom. Higher amounts of sugars were found in GS, while higher amounts of organic acids were recorded in GCN. Unsaturated fatty acids predominated over saturated fatty acids. GCN revealed higher antioxidant activity, while GS exhibited inhibitory potential against human breast and cervical carcinoma cell lines. No cytotoxicity in non-tumour liver primary cell culture was observed for the different samples. Both samples possessed antibacterial and antifungal activities, in some cases even better than the standard antimicrobial drugs. This is the first study reporting a comparison of chemical compounds and bioactivity of G. lucidum samples from different origins.
Fluvial terraces of the northwest Iberian lower Miño River.
Viveen, W. ; Schoorl, J.M. ; Veldkamp, A. ; Balen, R.T. van; Vidal-Romani, J.R. - \ 2013
Journal of Maps 9 (2013)4. - ISSN 1744-5647 - p. 513 - 522.
sea-level change - tectonic activity - portugal - uplift - climate - reconstruction - pleistocene - evolution - incision - deposits
A new fluvial terrace map with a tectonic framework for the northwest Iberian lower Miño River is presented. It is the first integrated map to cover the entire lower, 67-km reach of the Miño River, and to cover both the Spanish and Portuguese side of the river. The map is presented at a scale of 1:200,000, although its features were mapped at a scale of 1:5000. Various map layers can be viewed, such as a digital elevation model (DEM), fluvial sediment thickness layers, a palaeoflow direction layer, a lineament and fault layer, and two terrace and tectonic basin layers, showing up to 10 fluvial terraces and a floodplain level. Interpretation of the map shows that next to regional tectonic uplift and glacioeustacy, local basin subsidence and small-scale block movement are very important for the fluvial network, localised fluvial terrace formation, and preservation.
Multi-scale tectonic controls on fluvial terrace formation in a glacioeustatically-dominated river system: inference from the lower Min¿o terrace record
Viveen, W. - \ 2013
Wageningen University. Promotor(en): Tom Veldkamp, co-promotor(en): R.T. van Balen; J.R. Vidal Romani; Jeroen Schoorl. - S.l. : s.n. - ISBN 9789461737281 - 222
fluvial soils - terrassen - rivierterrasgronden - tektoniek - klimaatverandering - zeespiegelschommelingen - rivieren - rivierdalen - spanje - portugal - fluvial soils - terraces - river terrace soils - tectonics - climatic change - sea level fluctuations - rivers - river valleys - spain - portugal
The general aim of this thesis is to untangle the interacting effects of climate, glacioeustacy, and regional, and local tectonics on fluvial terrace formation. The NW Iberian lower Miño River valley was chosen as a study site, because for this region, a very detailed, long-term, climate record is available. The lower Miño is situated near the Atlantic Ocean, which ensures that the influence of changing past sea levels was registered in the terrace record. Then, there is controversy about the presence or absence of tectonic activity, although a well-developed network of pre-existing faults and seismic activity in the region suggest that tectonic activity is present. Lastly, a completely preserved terrace sequence makes it possible to study the evolution of the area in detail. These, and more details, are found in Chapter 1.
In Chapter 2, a regional assessment of recent tectonic activity is made. Studies on faulted terrace deposits and the recognition of small, fault-bounded tectonic basins indicate the presence of neo-tectonic activity. Further evidence is gathered from a tectono-geomorphic analysis, whereby deeply incised valleys, as well as asymmetrically-developed tributary catchments, and the presence of knick points in river profiles that coincide with the presence of structural lineaments, show that the eastern part of the study area experiences tectonic deformation. It is proposed that due to the non-optimal angle between the orientation of the pre-existing faults, and the current horizontal stress orientation, these older faults are re-activated, resulting in strain transfer from one fault segment to another. This results in differential block movements leading to local extension and basin subsidence. Alternatively, strike-slip activity may have caused the tectonic basins, but for this mechanism no evidence was found.
The focus of Chapter 3 is on a local terrace staircase near the village of Vila Meã. First, the terrace staircase and associated fluvial deposits are described in detail. Then, an age model for the Vila Meã terraces is presented on basis of thermoluminescence and Cosmogenic Ray Exposure (CRE) dating. Minimum ages of up to 650 ka are calculated. On basis of these ages, and terrace surface altitudes, maximum incision rates of 0.07 to 0.09 m ka-1 are reconstructed. It is then discussed that these rates can be used as proxies for regional, vertical tectonic uplift. In the final part of the Chapter, new ideas are presented on the evolution of the lower Miño fluvial terraces. Based on observations made from the terrace deposits, and the proximity of a narrow, steep continental shelf, it is suggested that the fluvial terraces were formed during the initial period of sea level fall, and subsequently incised. Vertical uplift would then have occurred to preserve the terraces above the current river bed.
In Chapter 4, the focus shifts from a local terrace staircase to the regional terrace record. The entire 55-km long terrace section of the lower Miño is investigated, and 4 selected terrace transects are discussed in terms of number of terraces and sedimentology. Because there is disagreement on the exact number of terraces and their correlations, a new long-distance terrace correlation scheme is presented. The new scheme is based on studies of weathered quartzite gravels in the 4 selected transects. Observed similarities in weathering rate between the transects leads to a proposed terrace correlation gradient of 1 m km-1. The often used correlation model that the terraces tread parallel to the current river bed (gradient 0 m km-1) is then rejected. The second half of the Chapter focuses on a longitudinal profile modelling experiment with the FLUVER 2 model. The evolution of the entire Miño-Sil system is modelled over a time period of 450 ka. The outcomes show that a regional uplift rate of 0.08 m ka-1 in combination with glacioeustatic movements seem to be responsible for terrace formation in the lower Miño valley, and thus confirm the earlier hypotheses in Chapter 3. Climate-induces variations in discharge intensity or timing do not have a dominant effect on terrace formation. The outcomes furthermore indicate that the CRE ages presented in Chapter 3, appear to be very close to exact timing of terrace abandonment.
The results of the foregoing Chapters are integrated and implemented in Chapter 5, resulting in a new, detailed, fluvial terrace map of the entire 67-km reach of the lower Miño River. Both the Spanish and Portuguese part is incorporated. The map is derived from detailed mapping from a 5-m Digital Elevation Model (DEM) and over 1500 hours of fieldwork. The map shows the regional distribution of 10 terrace levels and one floodplain level, as well as 9 tectonic basins. A layer with fault elements gives a structural tectonic context to the map. Additional layers give information about more than 400 sites with mapped terrace sediment thicknesses and palaeoflow directions. Results from this mapping exercise show the highly fragmented nature of terrace and basin distribution, which is controlled by N-S, E-W and NW-SE trending faults. The map also suggests the presence of unpaired terraces along the river, which may be caused by localised differential movements of tectonic blocks.
These localised movements are the topic of Chapter 6. Here, the interactions between regional vertical uplift, local basin subsidence, and unequal uplift on both sides of the Miño River on terrace formation are investigated by means of a forward modelling exercise with the TERRACE model. The model simulations that match best with mapped terraces and fluvial sediment thicknesses are the ones that incorporate all three effects of vertical uplift, basin subsidence, and unequal uplift. This shows that terrace preservation is the complex end result of three, interacting, tectonic processes. A regional uplift rate of 0.10 m ka-1 gave the best results, which is slightly higher than the rate of 0.08 m ka-1 presented in Chapter 3. This confirms that regional uplift increases from the coast towards the east, which is in agreement with the findings of Chapter 2. Another important result is that the interacting effect of the three aforementioned tectonic processes can lead to fill terraces one valley side, and strath terraces at the other.
In Chapter 7, all findings of the previous Chapters are combined. The separate effects of climate change, glacioeustacy, and regional and local tectonic movements on fluvial terrace formation are discussed. This shows that in many published terrace correlation schemes for tectonically active regions, the effects of multi-scale tectonics are insufficiently incorporated or considered. The same applies for the possible effects of variable uplift pulses over middle to late Quaternary timescales. This leads for instance to the separation of fill and strath terraces in a chronological context, because they are still thought to be the resultant of climate-triggered changes in discharge and sediment load of the river. But this thesis shows that they can form at the same time due to localised tectonic movements. The Chapter concludes with a number of recommendations on how to incorporate tectono-geomorphic analysis in fluvial terrace research, which will lead to a better understanding of tectonic control on fluvial terrace formation world-wide.
State of the Art on Energy Efficiency in Agriculture, Country data on energy consumption in different agroproduction sectors in the European countries
Visser, C.L.M. de; Buisonje, F.E. de; Ellen, H.H. ; Stanghellini, C. ; Voort, M.P.J. van der - \ 2012
agrEE - 68
energiegebruik - landbouwproductie - dierlijke productie - gewasproductie - energie - efficiëntie - levenscyclusanalyse - finland - duitsland - griekenland - nederland - polen - portugal - energy consumption - agricultural production - animal production - crop production - energy - efficiency - life cycle assessment - finland - germany - greece - netherlands - poland - portugal
Energy efficiency is the goal of efforts to reduce the amount of energy required to provide products and services. The general term "energy efficiency", when applied to agriculture, reflects changes in technology, governmental and EC policies – including the Common Agricultural Policy, climate change on a broad scale and local weather patterns, and farming management practices. There is not a single measure to describe, ensure, or improve energy efficiency. Instead, in the energy balance for a given production process, a variety of indicators may serve and support energy efficiency analysis. The results of this study are based on the specific input of primary energy per cultivation area (GJ ha-1) and on the specific input of primary energy per ton of agricultural product (GJ t-1). All the measures that are suitable to reduce the specific energy input, will improve energy efficiency (the energy efficiency measures). Improving energy efficiency of agricultural production contributes directly to the reduction of greenhouse gas (GHG) emissions, particularly carbon dioxide.
|Waar is Europa's natuurgeld het meeste waard?
Woestenburg, M. ; Sluis, T. van der; Pedroli, G.B.M. - \ 2012
Landwerk 13 (2012)6. - ISSN 1567-1844 - p. 22 - 25.
cultuurlandschap - regionale ontwikkeling - portugal - italië - cultural landscape - regional development - italy
In Nederland worden miljoenen eurp's gestoken in het herstel van oude en ecologisch interessante cultuurlandschappen voor een aantrekkelijk vestigingsklimaat. In Italië en Portugal zijn veel van zulke cultuurlandschappen nog intact, maar ontbreekt het juist aan geld voor het beheer. Vanuit Europees perspectief roept dat de vraag op waar investeringen voor Natura 2000 het meest lonen
Hg transfer from contaminated soils to plants and animals
Rodrigues, S.M. ; Henriques, B. ; Reis, A.T. ; Duarte, A.C. ; Pereira, E. ; Romkens, P.F.A.M. - \ 2012
Environmental Chemistry Letters 10 (2012)1. - ISSN 1610-3653 - p. 61 - 67.
potentially toxic elements - chloralkali plant - available pools - total mercury - part ii - speciation - transport - portugal - slovenia - samples
Understanding the transfer of mercury (Hg) from soil to crops is crucial due to Hg toxicity and Hg occurrence in terrestrial systems. Previous research has shown that available Hg in soils contributes to plant Hg levels. Plant Hg concentrations are related to soil conditions and plant characteristics. Mechanistic models describing such soil–plant interactions are however difficult to quantify. Here we performed a field study in agricultural, mining and industrial areas in Portugal to evaluate potential food chain risks. The uptake of Hg by Italian ryegrass, ryegrass, orchard grass, collard greens and rye was measured to calculate daily intakes (DI) of Hg for cows and sheep grazing. A total of 136 soil samples and 129 plant samples were analysed. Results show that total Hg concentrations ranged from 0.01 to 98 mg kg-1 in soils; 0.01–5.4 mg kg-1 in shoots and 0.01–42 mg kg-1 in roots. Calculated DI ranged from 0.18 to 132 mg d-1 for cows, and from 0.028 to 23 mg d-1 for sheep. In 27 grassland sites, daily intakes exceeded the acceptable daily intake of both cows and sheep in view of food safety considering Hg in animal kidneys evidencing potential risks to human health. The transfer of Hg from soil to crops was described using empirical Freundlich-type functions. For ryegrass, orchard grass and collard greens, the soil-to-root or soil-to-shoot transfer of Hg appeared to be controlled by the total soil Hg concentration and levels of Alox and Feox. Empirical functions allowed us to obtain realistic estimates of Hg levels in crops and can be used as an alternative to mechanistic models when evaluating food chain risks of Hg contamination in agricultural soils.
Fast chromatographic separation for the quantitation of the main flavone dyes in Reseda luteola (weld)
Villela, A. ; Klift, E.J.C. van der; Mattheussens, E.S.G.M. ; Derksen, G.C.H. ; Zuilhof, H. ; Beek, T.A. van - \ 2011
Journal of Chromatography. A, Including electrophoresis and other separation methods 1218 (2011)47. - ISSN 0021-9673 - p. 8544 - 8550.
performance liquid-chromatography - diode-array detection - l. - identification - quantification - bilobalide - portugal
In the past decades, there has been a renewed interest in the use of natural dye plants for textile dyeing, e.g. Reseda luteola (weld). Its main yellow dye constituents are the flavones luteolin-7,3'-O-diglucoside, luteolin-7-O-glucoside and luteolin. The aim of this work was to develop a simple validated industrially usable quantitative method to assess the flavone content of R. luteola samples. The flavones were overnight extracted from the dried and ground aerial parts of the plant at room temperature via maceration with methanol-water 8:2. Afterwards, they were quantified through internal standardisation against chrysin by RP-HPLC-UV at 345nm. The efficiency of the one-step extraction was 95%. The limits of detection (LOD) and quantitation (LOQ) were =1ng and =3ng, respectively, providing ample sensitivity for the purpose. The precision expressed as relative standard deviation of the entire method was
Meeting the challenge of marginalization processes at the periphery of Europe
Breman, B.C. ; Vihinen, H. ; Tapio-Bistrom, M.L. ; Pinto-Correia, T. - \ 2010
Public Administration 88 (2010)2. - ISSN 0033-3298 - p. 364 - 380.
multifunctionality - agriculture - portugal - policy - land
Under the influence of the enlargement of the European Union, there is now a renewed concern for marginalization processes in rural areas. Especially in countries at the periphery of Europe, these processes often have a large-scale and multifaceted character. As agriculture and rural areas have become dissociated, the marginalization or success of the one no longer necessarily affects the other, and not necessarily in the same way. Dealing with the phenomenon in policy terms requires tools to explicate it. In this article, we present a simple typology of marginalization processes as a first step to its disentangling. The typology is applied to Finland and Portugal, countries at the periphery of Europe. The results strengthen the idea that different processes with different characteristics are going on at the same time, requiring specific approaches.
The dynamics of cork oak systems in Portugal: the role of ecological and land use factors
Acácio, V.C. - \ 2009
Wageningen University. Promotor(en): Frits Mohren; F. Castro Rego, co-promotor(en): Milena Holmgren Urba. - [S.l.] : S.n. - ISBN 9789085855040 - 208
quercus suber - landgebruik - agroforestry - natuurbranden - degradatie - landdegradatie - verandering - bossen - struiken - middellandse-zeegebied - bosecologie - kurk - quercus - portugal - plantensuccessie - herbegroeiing - mediterrane ecosystemen - quercus suber - land use - agroforestry - wildfires - degradation - land degradation - change - forests - shrubs - mediterranean region - forest ecology - cork - quercus - portugal - plant succession - revegetation - mediterranean ecosystems
Vegetation degradation and desertification occur in many semiarid ecosystems worldwide, particularly in the Western Mediterranean Basin. A peculiar semiarid Mediterranean land use system dominates the landscape of southern Portugal where cork oak (Quercus suber) is the main tree species. This system is the result of both ecological and land use dynamics that shaped the landscape for centuries and created a fine-grained mosaic landscape, which includes four main types of vegetation patches: cork oak woodlands (higher tree density), cork oak montados (lower tree density), shrublands and grasslands. Each patch can be conceived as a vegetation state that is reached and maintained in different ways. Transitions between states are triggered often by a combination of human management and climatic circumstances. I hypothesize that cork oak woodlands and shrublands in southern Portugal represent alternative stable states, which change slowly or not at all in the absence of human intervention. Failures in natural regeneration of cork oak trees triggered by grazing pressure and human overexploitation can be the cause of a shift to the alternative stable state of shrublands, especially in very dry conditions. Stable and expanding shrublands may therefore be a sign of land desertification in southern Portugal, representing an irreversible transition. This PhD proposal aims to evaluate if cork oak woodlands and shrublands represent alternative stable states in southern Portugal and what are the ecological and land use mechanisms underlying their resilience and persistence. Overall methodology The study area is located at Serra do Caldeirão, Algarve, southern Portugal. The persistence and dynamics of cork oak woodlands and shrublands, transition probabilities between vegetation states, and correlation between transitions and environmental variables will be analyzed through the observation of aerial photos between 1958 and 2002 for the study area with the help of a GIS (Geographical Information System). Markov matrix analysis and multivariate analysis will be used. Limitations for seedling establishment will be analysed through an experimental design carried out in different vegetation states. Finally, human management, motivations for land use decisions, behaviour towards the cork oak system, and sociological characterization of landowners will be investigated through landowner interviews.
Final Results of the Tisza, Guadiana and Inner Mongolia Regional Case-studies
Werners, S.E. ; Bindi, M. ; Cots, F. ; Dai, X. ; Flachner, Z. ; Harnos, Z. ; Matczak, P. ; McEvoy, D. ; Moriondo, M. ; Lugeri, N. ; Nabuurs, G.J. ; Neufeldt, H. ; Tàbara, J.D. ; Trombi, G. ; West, J. - \ 2008
Norwich, UK : ADAM (ADAM Deliverables D-P3D.4 (M39)) - 238
klimaatverandering - landgebruik - waterbeheer - rivieren - stroomgebieden - spanje - portugal - hongarije - china - climatic change - land use - water management - rivers - watersheds - spain - portugal - hungary - china
This deliverable reports on the work done in ADAM work package P3d. It examines the constraints and opportunities for mainstreaming adaptation to climate change in land use and water management in three study regions: the Guadiana River Basin in Spain and Portugal, the Tisza River Basin in Hungary and the Alxa region in western Inner Mongolia, China
Blueprint for EUROSCAPE 2020 : reframing the Future of the European Landscape : policy visions and research report
Wascher, D.M. ; Pedroli, B. - \ 2008
[S.l.] : JRC European Commission [etc.] - 48
landschap - regionale planning - portugal - polen - italië - landen van de europese unie - landschapsplanning - landscape - regional planning - portugal - poland - italy - european union countries - landscape planning
This Blueprint for EUROSCAPE 2020 proposes to undertake a radically new strategic operational approach for the European Union when defining targets for its territorial policies. The key principles are: (1) to establish a policy monitoring for rural development on the basis of a landscape functions; (2) introduce new spatial planning instruments to support Polycentric Regions and Vital Bridges; and (3) develop new forms of governance involving local and regional authorities, people and decision-makers.
Soil water repellency in an old and young pasture in relation to N application
Sonneveld, M.P.W. - \ 2008
Soil Use and Management 24 (2008)3. - ISSN 0266-0032 - p. 310 - 317.
sandy soil - preferential flow - moisture - management - movement - portugal - patterns
Ageing of pastures is likely to affect the degree of potential water repellency in the long term, whereas seasonal variation on a shorter term affects the actual repellency of soils. A 1-year study on two pastures of different ages was conducted on a sandy soil to assess changes in the degree of potential and actual water repellency in relation to different levels of applied nitrogen (N). Sampling was carried out on four dates (April, June, August and October) to determine soil moisture content and both potential and actual water repellency at three depths (0¿25, 25¿50 and 50¿75 cm). The relative number of potentially wettable samples for the young pasture (5 years) ranged from 64% (0¿25 cm) to 96% (25¿50 cm) to 100% (50¿75 cm). For the old pasture (38 years) this ranged from 29 to 66 to 94%. The transition zone in which topsoil samples could be either wettable or water repellent ranged from 18 to 23% (v/v) for the young pasture compared with a range from 29 to 32% (v/v) for the old pasture. Thus, ageing pastures may result in both moving as well as decreasing transition zones over time. A positive relationship between increased inputs of fertilizer N, higher DM yields, lower soil water contents and higher degrees of water repellency was found for the old pasture for the August series. This suggests that seasonal variation in water repellency can be further re-enforced through nutrient management.
|Rocha geen directe bedreiging voor Conference
Maas, F.M. - \ 2007
De Fruitteelt 97 (2007)37. - ISSN 0016-2302 - p. 12 - 13.
fruitteelt - vruchtbomen - peren - rassen (planten) - gewaskwaliteit - gewasproductie - onderzoekers - conferenties - portugal - fruit growing - fruit trees - pears - varieties - crop quality - crop production - research workers - conferences - portugal
Van 22 tot 26 mei 2007 vond in het Portugese Peniche het tiende Internationale Perensymposium plaats. Aan deze bijeenkomst, die werd georganiseerd door het International Society for Horticultural Sciences (ISHS), namen tweehonderd onderzoekers uit dertig landen deel
Editorial: Water repellence of soils: new insights and emerging research needs
Doerr, S.H. ; Ritsema, C.J. ; Dekker, L.W. ; Scott, D.F. ; Carter, D. - \ 2007
Hydrological Processes 21 (2007)17. - ISSN 0885-6087 - p. 2223 - 2228.
hydrophobicity - portugal - rainfall - dynamics - impact - flow
An increasing awareness of the occurrence and implications of soil water repellence has caused a surge in research activity addressing this phenomenon in recent years. This has involved not only the disciplines of hydrology, soil, and related environmental sciences, but increasingly also biology, chemistry, physics, and surface sciences, which has allowed elucidation of the causes and behaviour of soil water repellence based on first order principles. Furthermore, novel approaches and advances in technology have allowed examination of its causes and implications at increasingly coarse and fine spatial and temporal scales. The 19 papers presented in this special issue exemplify this trend by bringing together studies from diverse disciplines and presenting the latest advances regarding the origin, occurrence, controls, hydrological effects, and amelioration of soil water repellence. Here we aim to summarize, evaluate and set into context some of the new insights arising from these studies and also attempt to identify the key current and likely future research gaps related to water repellence in soils
Occurrence, prediction and hydrological effects of water repellency amongst major soil and land-use types in a humid temperate climate
Doerr, S.H. ; Shakesby, R.A. ; Dekker, L.W. ; Ritsema, C.J. - \ 2006
European Journal of Soil Science 57 (2006)5. - ISSN 1351-0754 - p. 741 - 754.
sandy soils - wetting patterns - organic-matter - dutch coast - variability - moisture - parameter - portugal - rainfall - runoff
Knowledge of soil water repellency distribution, of factors affecting its occurrence and of its hydrological effects stems primarily from regions with a distinct dry season, whereas comparatively little is known about its occurrence in humid temperate regions such as typified by the UK. To address this research gap, we have examined: (i) water repellency persistence (determined by the water drop penetration time method, WDPT) and degree (determined by the critical surface tension method, CST) for soil samples (0¿5, 10¿15 and 20¿25 cm depth) taken from 41 common soil and land-use types in the humid temperate climate of the UK; (ii) the supposed relationship of soil moisture, textural composition and organic matter content with sample repellency; and (iii) the bulk wetting behaviour of undisturbed surface core samples (0¿5 cm depth) over a period of up to 1 week. Repellency was found in surface samples of all major soil textural types amongst most permanently vegetated sites, whereas tilled sites were virtually unaffected. Repellency levels reached those of the most severely affected areas elsewhere in the world, decreased in persistence and degree with depth and showed no consistent relationship with soil textural characteristics, organic matter or soil moisture contents, except that above a water content of c. 28% by volume, repellency was absent. Wetting rate assessments of 100 cm3 intact soil cores using continuous water contact (¿20 mm pressure head) over a period of up to 7 days showed that across the whole sample range and irrespective of texture, severe to extreme repellency persistence consistently reduced the maximum water content at any given time to well below that of wettable soils. For slightly to moderately repellent soils the results were more variable and thus hydrological effects of such repellency levels are more difficult to predict. The results imply that: (i) repellency is common for many land-use types with permanent vegetation cover in humid temperate climates irrespective of soil texture; (ii) supposedly influential parameters (texture, organic matter, specific water content) are poor general predictors of water repellency, whereas land use and the moisture content below which repellency can occur seem more reliable; and (iii) infiltration and water storage capacity of very repellent soils are considerably less than for comparable wettable soils.
Near-surface distributions of soil water and water repellency under three effluent irrigation scemes in a blue gum (Eucalyptus globulus) plantation
Thwaites, L.A. ; Rooij, G.H. de; Salzman, S. ; Allinson, G. ; Stagnitti, F. ; Carr, R. ; Versace, V. ; Struck, S. ; March, T. - \ 2006
Agricultural Water Management 86 (2006)1-2. - ISSN 0378-3774 - p. 212 - 219.
spatial variability - preferential flow - wetting patterns - pinus-radiata - sandy soils - portugal - hydrophobicity - management - australia - moisture
Water repellent soils are difficult to irrigate and susceptible to preferential flow, which enhances the potential for accelerated leaching to groundwater of hazardous substances. Over 5 Mha of Australian soil is water repellent, while treated municipal sewage is increasingly used for irrigation. Only if a critical water content is exceeded will repellent soils become wettable. To avoid excessive loss of water from the root zone via preferential flow paths, irrigation schemes should therefore aim to keep the soil wet enough to maintain soil wettability. Our objective was to monitor the near-surface water content and water repellency in a blue gum (Eucalyptus globulus) plantation irrigated with treated sewage. The plantation's sandy soil surface was strongly water repellent when dry. For 4 months, three rows of 15 blue gum trees each received no irrigation, three other rows received 50% of the estimated potential water use minus rainfall, and three more rows received 100%. During this period, 162 soil samples were obtained in three sampling rounds, and their water content (% dry mass) and degree of water repellency determined. Both high and low irrigation effectively wetted up the soil and eliminated water repellency after 2 (high) or 4 (low) months. A single-peaked distribution of water contents was observed in the soil samples, but the water repellency distribution was dichotomous, with 44% extremely water-repellent and 36% wettable. This is consistent with a threshold water content at which a soil sample changes from water repellent to wettable, with spatial variability of this threshold creating a much wider transition zone at the field scale. We characterized this transition zone by expressing the fraction of wettable samples as a function of water content, and demonstrated a way to estimate from this the wettable portion of a field from a number of water content measurements. To keep the plantation soil wettable, the water content must be maintained at a level at which a significant downward flux is likely, with the associated enhanced leaching. At water contents with negligible downward flux, the field is water repellent, and leaching through preferential flow paths is likely. Careful management is needed to resolve these conflicting requirements.