Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
371
result(s) for
"Alien plants Control."
Sort by:
The ecological and economic benetfis of investing in the rehabilitation and management of the Kluitjieskraal Wetland in the upper Breede River Catchment, South Africa
Despite growing water quality issues in South Africa, there have been few assessments of ecological infrastructure (EI) investment focussed on water quality enhancement. The Kluitjieskraal Wetland in the upper Breede River Catchment was selected for such an assessment, given that it has been the focus of longterm rehabilitation and management interventions (including the control of invasive alien plants and the 'plugging' of drainage canals) and is strategically located immediately downstream of the Wolseley town and its wastewater treatment works. This paper reports on the ecological and economic outcomes of these interventions. The study demonstrates the application of an interdisciplinary assessment approach for investment in EI, which included stakeholder engagement, and an ecological, hydrological and economic assessment. Underpinning the study was a WET-Health and WET-Ecoservices assessment and a detailed WRSM2000-Pitman model configured for the wetland in a rehabilitated present-day scenario and for a degraded scenario without interventions. A key outcome of the interventions was an increase of 11 ha of wetland area (and associated vegetation and sediments) in contact with low to medium flows, thereby significantly increasing the wetland's capacity to assimilate nutrients. Based on the replacement-cost method applied in the study, the water quality enhancement benefits of the interventions were valued at 1 201 301 ZAR/a; considerably higher than the combined contribution of the other ecosystem services valued, namely, sediment retention and livestock grazing. While the functionality of the wetland has been significantly enhanced, the recovery of the vegetation from its historically disturbed state to a more natural state is limited to localized areas where species characteristic of Breede Alluvium Fynbos wetlands (including the Critically Endangered Leucadendron chamelaea) persist.
Journal Article
Monitoring invasive alien plants dynamics: application in restored areas
In environmental restoration, evaluating the effect of control actions on alien species is essential for a correct assessment of the success of the restoration. A simple method for the evaluation of the dynamics of alien plants after manual and mechanical control in restored areas is proposed in this work. This method is based on the cover-abundance of alien plants, the size of the inventoried area and subsequently corrected with the degree of invasiveness based on national catalogues. Alien plants data abundances are obtained from floristic relevés retrieved from the restoration actions, carried out in the Eo River (Spain) during the LIFE Fluvial project (2018–2021). The Invasive Alien Plants Index (IAPI) was calculated, before and after the control actions for three ecological units (fluvio-estuarine, riverbank and lake). In all cases, index decreases after the control actions and it is sensitive to the changes that may occurs as recolonization by new alien species. As a whole, in the Eo River, a decrease of 53% of the IAPI has been obtained from 2018 to 2021, which estimate the effect of alien plants control. This indicator is applicable to any type of habitat, ecosystem or region and is adapted to different administrative areas that have published an official list of invasive species.
Journal Article
Alien balsams, strawberries and their pollinators in a warmer world
Background
Strawberries are a common crop whose yield success depends on the availability of pollinators. Invasive alien plants, such as
Impatiens glandulifera
and
I. parviflora
, are also attractive for bees and hoverflies, respectively, and occur in close proximity to strawberry cultivation areas. The aim of the study was to test whether alien plants may decrease pollination of strawberry cultivation. However, even if the pollinators are abundant, efficiency of their pollination may decrease as a result of revisits of flowers that were already probed. It is addressed by pollinators by scent marking. Moreover, such revisits can be determined by nectar replenishment, which may occur rapidly in nectar-rich flowers. We studied revisits to
I. glandulifera
by bumblebees and defined the factors that influence the probability of revisits (air temperature; pollinator species; family caste and size; flower area; sun radiation; and time of day).
Results
We found that the two alien species decreased the number of pollinators visiting strawberries. Apoidea, Bombini and Syrphidae significantly decreased on
Fragaria
×
ananassa
when alien
Impatiens
were present. We also revealed the influence of increasing air temperature on bumblebee foraging, which was particularly significant for female workers. At very high temperatures (> 37°C), bumblebee males revisited probed flowers less often than female workers.
Conclusions
Our results demonstrate that in experimental conditions attractive alien species decrease pollination of strawberries, which may negatively affect production of this crop. Although the results have not been verified in real-life strawberry fields yet, we recommend that alien plant species that share the same pollinators and occur in close proximity of strawberries are controlled. Moreover, we found that revisits of probed flowers may weaken feeding efficiency of bumblebees. If revisits are not induced by nectar replenishment, then global warming may pose a serious threat to the survival of colonies, which may have consequences also for the plants that attract them, e.g., for strawberries.
Journal Article
The ecological and economic benefits of investing in the rehabilitation and management of the Kluitjieskraal Wetland in the upper Breede River Catchment, South Africa
Despite growing water quality issues in South Africa, there have been few assessments of ecological infrastructure (EI) investment focussed on water quality enhancement. The Kluitjieskraal Wetland in the upper Breede River Catchment was selected for such an assessment, given that it has been the focus of long-term rehabilitation and management interventions (including the control of invasive alien plants and the 'plugging' of drainage canals) and is strategically located immediately downstream of the Wolseley town and its wastewater treatment works. This paper reports on the ecological and economic outcomes of these interventions. The study demonstrates the application of an interdisciplinary assessment approach for investment in EI, which included stakeholder engagement, and an ecological, hydrological and economic assessment. Underpinning the study was a WET-Health and WET-Ecoservices assessment and a detailed WRSM2000-Pitman model configured for the wetland in a rehabilitated present-day scenario and for a degraded scenario without interventions. A key outcome of the interventions was an increase of 11 ha of wetland area (and associated vegetation and sediments) in contact with low to medium flows, thereby significantly increasing the wetland's capacity to assimilate nutrients. Based on the replacement-cost method applied in the study, the water quality enhancement benefits of the interventions were valued at 1 201 301 ZAR/a; considerably higher than the combined contribution of the other ecosystem services valued, namely, sediment retention and livestock grazing. While the functionality of the wetland has been significantly enhanced, the recovery of the vegetation from its historically disturbed state to a more natural state is limited to localized areas where species characteristic of Breede Alluvium Fynbos wetlands (including the Critically Endangered Leucadendron chamelaea) persist. KEYWORDS wetland rehabilitation nutrient assimilation replacement costs invasive alien plant control
Journal Article
Use of a rapid roadside survey to detect potentially invasive plant species along the Garden Route, South Africa
Early detection of emerging or sleeper weeds and monitoring of alien plant invasions forms the foundation of effective invasive alien plant management. Using a rapid roadside survey technique, we aimed to (1) establish a baseline of alien plant distribution and abundance along roads in the Garden Route, South Africa, and (2) identify priority species (particularly sleeper weeds) and priority areas to inform appropriate management action. We surveyed along 530 km of roads and recorded 109 alien and/or extralimital species across 1942 point locations. Of these, 35 species were considered to be sleeper weeds on account of displaying estimated dispersal distances distinctive of invasive plants and not being listed by the South African Plant Invaders Atlas (SAPIA) or regulated by South African legislation. Roads along natural forest and fynbos vegetation (often within the Garden Route National Park) displayed lower incidences of alien plants than those associated with degraded or transformed land, with roads along farmland associated with the highest incidences of alien plants. Roads in the Southern Cape region had more species and higher densities of alien plants than roads in the Tsitsikamma region, and a few species were exclusive to either. Conservation implications: Our inventory contributed significant new records and range extensions to SAPIA, while the identified sleeper weeds offered suggestions for species that may be considered for regulation under the National Environmental Management: Biodiversity Act of South Africa. We furthermore provided information to facilitate (1) timely management of emerging invasive alien plants, (2) prioritisation of species and areas for management action, and (3) future monitoring of alien plants in the Garden Route National Park and surrounds.
Journal Article
The restoration of gravelly floodplain vegetation and endemic plants to riparian habitat in a Japanese river
Aster kantoensis
, an endangered and monocarpic perennial plant species, is endemic to the gravelly floodplain of a few rapid flowing rivers in eastern central Japan. In recent years, an extreme declining trend in the species has been accelerated due to the strong negative influence by invasion of an alien grass,
Eragrostis curvula
. A restoration project aimed at recovering the original condition of the floodplain in the Kinu River, central Japan, has been started. To determine the possibility of successful restoration as well as its habitat preferences, I carried out some seed sowing experiments. In April 2003, seeds collected from a seminatural habitat were sown (54,000 seeds) in the restoration site (1.2 ha), where flood frequency, substrate condition, and control of alien plants are combined to form different habitat conditions. Seedling survival, flowery, and seed production were subsequently monitored from 2003 to 2005. Seed cohorts completed their life cycles within 3 years, and mean fitness of 927 was achieved. Performance of
A. kantoensis
seedlings was generally greater for environmental variables of sandy-type substrate and/or with control of alien plants. In addition, there were significant negative correlations between percentage survival, percentage flowery, and seed production with vegetation cover and coverage of
E. curvula
. The results confirm that, if safe sites with sparse vegetation exist, irrespective of their substrate condition, as well as seed sources of river endemics in natural habitats, restoration of riparian vegetation including river endemics is possible. The aggressive alien species
E. curvula
should be taken into consideration.
Journal Article
Integrated pest management of Tuta absoluta: practical implementations across different world regions
The South American tomato pinworm,
Tuta absoluta
(Meyrick) (Lepidoptera: Gelechiidae), has invaded most Afro-Eurasian countries and is threatening worldwide tomato production. Various strategies have been developed and implemented to manage this pest. Here, we present a timely review on the up-to-date development and practical implementation of integrated pest management (IPM) programs for tomato crops across different world regions infested by
T. absoluta
. While insecticide resistance is a growing concern, biological control via releasing or conserving arthropod natural enemies and sex pheromone-based biotechnical control are the most successful management practices. Agronomic control-related research is an emerging area where the soil fertilization and/or irrigation, as well as breeding of resistant cultivars, has the potential to enhance IPM effectiveness. Grower survey responses in the native areas (i.e., South America), early-invaded areas (i.e., first report between 2006 and 2012) and newly invaded areas (i.e., first report after 2012) showed that the control programs evolved along with the areas and time since invasion. Growers in the early-invaded areas shifted more rapidly from chemical control to biological control compared to those from the native area. In all concerned regions, the pest control failure risk following chemical insecticide applications and the high cost associated with either biological or biotechnical control methods have been the greatest concerns for growers. The information gathered from the native and/or early-invaded areas may help achieve a more effective management in newly invaded areas. Lastly, researchers are expected to break the bottlenecks of some key issues that would enable lowering application cost of novel biorational alternative management options.
Journal Article