Search results for "ECOSYSTEMS"

Climate change and cyclic predator-prey population dynamics in the high Arctic.

2009

The high Arctic has the world's simplest terrestrial vertebrate predator–prey community, with the collared lemming being the single main prey of four predators, the snowy owl, the Arctic fox, the long-tailed skua, and the stoat. Using a 20-year-long time series of population densities for the five species and a dynamic model that has been previously parameterized for northeast Greenland, we analyzed the population and community level consequences of the ongoing and predicted climate change. Species' responses to climate change are complex, because in addition to the direct effects of climate change, which vary depending on species' life histories, species are also affected indirectly due to…

Rīgas līča un Baltijas jūras zooplanktona daudzgadīgā dinamika un to kontrolējošie vides faktori

2005

Wide-scope screening of pharmaceuticals, illicit drugs and their metabolites in the Amazon River.

2021

Only a limited number of households in the Amazon are served by sewage collection or treatment facili- ties, suggesting that there might be a significant emission of pharmaceuticals and other wastewater contaminants into freshwater ecosystems. In this work, we performed a wide-scope screening to assess the occurrence of pharmaceuticals, illicit drugs and their metabolites in freshwater ecosystems of the Brazilian Amazon. Our study included 40 samples taken along the Amazon River, in three of its major tributaries, and in small tributaries crossing four important urban areas (Manaus, Santarém, Macapá, Belém). More than 900 compounds were investigated making use of target and suspect screenin…

Historical Landscape Ecology of the Favorita Park in Palermo (Sicily)

2021

Historical Landscape Ecology of the Favorita Park in Palermo

Climate changes' effects on vegetation water stress in Mediterranean areas

2010

Many recent studies have demonstrated that CO(2) increase is driving the climate in Mediterranean areas towards important changes, mainly represented by a temperature increase and a contemporaneous rainfall reduction. Starting from this premise, the primary aim of the present study is to investigate the effects of potential climatic changes on vegetational stress in Mediterranean ecosystems. Particular attention is here focussed only on the plants' water stress in water controlled ecosystems, mainly related to soil water balance. The interactions among climate, soil and vegetation are evaluated numerically by means of an ecohydrological model. In this work, different future climatic scenari…

Contribution of local factors to the status of a groundwater dependent terrestrial ecosystem in the transboundary Gauja-Koiva River basin, North-East…

2021

Abstract A pilot study was carried out in the Matsi spring fen, southern Estonia to test a proposed methodology ( Terasmaa et al., 2020 ) for identifying potential effects of groundwater bodies on groundwater dependent terrestrial ecosystems (GDTE). A comprehensive hydrochemical and isotopic dataset was collected and analyzed using multivariate statistical methods to assess the origin of the groundwater discharging in the spring fen and to determine both the quantitative and qualitative aspects of GDTE-groundwater interdependence. The hydrochemical findings were complemented with the hydrogeological, hydrodynamical and botanical observations, and summarized into a conceptual model of the st…

Negative Engagement

2018

Negative engagement has steeply increased on the scholarly agenda along with the introduction of real time and social media, though negative experiences and emotions are as such not new phenomena. This chapter takes a future perspective and focuses on negative stakeholder engagement online in the context of organizations and brands, which increasingly face visible forms of negative stakeholder emotions or even fierce "shit storms". It begins by defining what negative stakeholder engagement refers to in the context of organizations and brands. The chapter introduces the development of negative engagement via related concepts. After introducing the concepts, the process and the outcomes of ne…

An invasive species may be better than none: invasive signal and native noble crayfish have similar community effects

2014

14 pages; International audience; Human activities have resulted in the decline of native crayfish and promoted the spread of invasive crayfish species in European fresh waters, threatening ecosystem structure and functioning. We compared effects of native noble crayfish (Astacus astacus), invasive signal crayfish (Pacifastacus leniusculus) and of the absence of crayfish on leaf litter breakdown and invertebrate prey density and biomass in stream ecosystems. In microcosm experiments, invertebrate shredder density was significantly reduced by crayfish presence but similarly affected by the two crayfish species. While crayfish did not directly influence leaf litter breakdown, their presence r…

Bridging Mediterranean cultures in the International Year of Soils 2015: A documentary exhibition on irrigation techniques in water scarcity conditio…

2017

The paper presents the activity performed at the University of Brescia by students and researchers, belonging to different Mediterranean cultures and different disciplines, to prepare a documentary exhibition on irrigation techniques in water scarcity conditions, on the occasion of the International Year of Soils 2015. Traditional irrigation techniques were identified as a key aspect of soil conservation and agricultural practices, to build living and autopoietic ecosystems, also in adverse climatic conditions, and to adapt to climatic changes. Being a structural source of ecosystem survival, and being based on long-lasting observation of the climate and of the environment, they have deep r…

Towards a network-based view of effective entrepreneurial ecosystems

2021

AbstractWe conceptualize entrepreneurial ecosystems as fundamentally reliant on networks and explore how and under what conditions inter-organizational networks lead an entrepreneurial ecosystem to form and evolve. It is widely accepted that entrepreneurial ecosystems possess a variety of symbiotic relationships. Research has focused considerable efforts in refining the structure and content of resources found within these networked relationships. However, merely focusing on actor-level characterizations dilutes the notion that social relationships change and are complex. There has been little conceptual treatment of the behavioral and governance factors that underpin how quality interactio…