37 research outputs found
Efeito antagônico de fungos predadores dos gêneros Monacrosporium, Arthrobotrys e Duddingtonia sobre larvas infectantes de Cooperia sp. e Oesophagostomum sp.
Historical land-cover/use in different slope and riparian buffer zones in watersheds of the state of São Paulo, Brazil
Tree Mortality in Mature Riparian Forest: Implications for Fremont Cottonwood Conservation in the American Southwest
Implementing environmental flows in integrated water resources management and the ecosystem approach
In many of the world’s river basins, the water resources are over-allocated and/or highly modified,
access to good quality water is limited or competitive and aquatic ecosystems are degraded. The decline in
aquatic ecosystems can impact on human well-being by reducing the ecosystem services provided by healthy
rivers, wetlands and floodplains. Basin water resources management requires the determination of water
allocation among competing stakeholders including the environment, social needs and economic development. Traditionally, this determination occurred on a volumetric basis to meet basin productivity goals.
However, it is difficult to address environmental goals in such a framework, because environmental condition
is rarely considered in productivity goals, and short-term variations in river flow may be the most important
driver of aquatic ecosystem health. Manipulation of flows to achieve desired outcomes for public supply,
food and energy has been implemented for many years. More recently, manipulating flows to achieve
ecological outcomes has been proposed. However, the complexity of determining the required flow regimes
and the interdependencies between stakeholder outcomes has restricted the implementation of environmental
flows as a core component of Integrated Water Resources Management (IWRM). We demonstrate through
case studies of the Rhône and Thames river basins in Europe, the Colorado River basin in North America
and the Murray-Darling basin in Australia the limitations of traditional environmental flow strategies in integrated water resources management. An alternative ecosystem approach can provide a framework for implementation of environmental flows in basin water resources management, as demonstrated by management of the Pangani River basin in Africa. An ecosystem approach in IWRM leads to management for agreed triple-bottom-line outcomes, rather than productivity or ecological outcomes alone. We recommend that environmental flow management should take on the principles of an ecosystem approach and form an integral part of IWRM
Effects of flooding on native and exotic plant seedlings: implications for restoring south-western riparian forests by manipulating water and sediment flows
Riparian vegetation: Degradation, alien plant invasions, and restoration prospects
Rivers are conduits for materials and energy; this, the frequent and intense disturbances that these systems experience, and their narrow, linear nature, create problems for conservation of biodiversity and ecosystem functioning in the face of increasing human influence. In most parts of the world, riparian zones are highly modified. Changes caused by alien plants - or environmental changes that facilitate shifts in dominance creating novel ecosystems - are often important agents of perturbation in these systems. Many restoration projects are underway. Objective frameworks based on an understanding of biogeographical processes at different spatial scales (reach, segment, catchment), the specific relationships between invasive plants and resilience and ecosystem functioning, and realistic endpoints are needed to guide sustainable restoration initiatives. This paper examines the biogeography and the determinants of composition and structure of riparian vegetation in temperate and subtropical regions and conceptualizes the components of resilience in these systems. We consider changes to structure and functioning caused by, or associated with, alien plant invasions, in particular those that lead to breached abiotic- or biotic thresholds. These pose challenges when formulating restoration programmes. Pervasive and escalating human-mediated changes to multiple factors and at a range of scales in riparian environments demand innovative and pragmatic approaches to restoration. The application of a new framework accommodating such complexity is demonstrated with reference to a hypothetical riparian ecosystem under three scenarios: (1) system unaffected by invasive plants; (2) system initially uninvaded, but with flood-generated incursion of alien plants and escalating invasion-driven alteration; and (3) system affected by both invasions and engineering interventions. The scheme has been used to derive a decision-making framework for restoring riparian zones in South Africa and could guide similar initiatives in other parts of the world. © 2007 The Authors.Articl
Riparian vegetation: degradation, alien plant invasions, and restoration prospects
Rivers are conduits for materials and energy; this, the frequent and intense disturbances that these systems experience, and their narrow, linear nature, create problems for conservation of biodiversity and ecosystem functioning in the face of increasing human influence. In most parts of the world, riparian zones are highly modified. Changes caused by alien plants - or environmental changes that facilitate shifts in dominance creating novel ecosystems - are often important agents of perturbation in these systems. Many restoration projects are underway. Objective frameworks based on an understanding of biogeographical processes at different spatial scales (reach, segment, catchment), the specific relationships between invasive plants and resilience and ecosystem functioning, and realistic endpoints are needed to guide sustainable restoration initiatives. This paper examines the biogeography and the determinants of composition and structure of riparian vegetation in temperate and subtropical regions and conceptualizes the components of resilience in these systems. We consider changes to structure and functioning caused by, or associated with, alien plant invasions, in particular those that lead to breached abiotic- or biotic thresholds. These pose challenges when formulating restoration programmes. Pervasive and escalating human-mediated changes to multiple factors and at a range of scales in riparian environments demand innovative and pragmatic approaches to restoration. The application of a new framework accommodating such complexity is demonstrated with reference to a hypothetical riparian ecosystem under three scenarios: (1) system unaffected by invasive plants; (2) system initially uninvaded, but with flood-generated incursion of alien plants and escalating invasion-driven alteration; and (3) system affected by both invasions and engineering interventions. The scheme has been used to derive a decision-making framework for restoring riparian zones in South Africa and could guide similar initiatives in other parts of the world