Search results for "Fishe"
showing 10 items of 2001 documents
Climate change exacerbates interspecific interactions in sympatric coastal fishes
2012
Summary 1. Biological responses to warming are presently based on the assumption that species will remain within their bioclimatic envelope as environmental conditions change. As a result, changes in the relative abundance of several marine species have been documented over the last decades. This suggests that warming may drive novel interspecific interactions to occur (i.e. invasive vs. native species) or may intensify the strength of pre-existing ones (i.e. warm vs. cold adapted). For mobile species, habitat relocation is a viable solution to track tolerable conditions and reduce competitive costs, resulting in ‘winner’ species dominating the best quality habitat at the expense of ‘loser’…
25S rDNA-based molecular monitoring of glomalean fungi in sewage sludge-treated field plots
2001
Recycling of sewage wastes in agriculture is likely to affect the biological activity of soils through contamination of ecosystems by pathogens and metallic or organic micropollutants. The impact of sewage sludge spreading under field conditions on arbuscular mycorrhiza (AM) formation by a community of glomalean fungi was evaluated using a nested polymerase chain reaction (PCR) and discriminating primers based on 25S rDNA polymorphisms to detect different fungal species within root systems. Medicago truncatula was grown in soil of field plots amended or not with a composted sewage sludge, spiked or not with organic or metallic micropollutants. Overall AM development in roots decreased with …
Distribution and diversity of fish species along the Sudanese Red Sea coast based on three combined trap and gillnet surveys
2021
Abstract On the western shore of the semi-enclosed coral-reef rich Red Sea, the 850 km coastline of the Red Sea State of the Republic of Sudan provides livelihoods to artisanal fishers, but the present state of the living natural resources and the impact of fisheries are poorly known. To provide a baseline on the biodiversity and fish abundance three fisheries research surveys spanning the entire Sudanese coast were carried out in 2012−13 designed around the seven Sudanese fisheries management areas. Baited traps and gillnets were employed to sample the various reef habitats and fish assemblages from inshore to deeper outer reef archipelagos. The highest species richness, functional diversi…
Social equity and marine protected areas: Perceptions of small-scale fishermen in the Mediterranean Sea
2020
Abstract Global conservation policy requires the scaling up of effectively and equitably managed networks of marine protected areas (MPAs). While progress has been made on spatial coverage, the fundamental aspects of effectiveness and equity are falling short. Past research has focused on management effectiveness in MPAs, but less attention has been given to social equity though it is an ethical imperative and instrumental to conservation. This study assessed the perceptions of SSF regarding recognitional, procedural and distributional dimensions of social equity using quantitative surveys in 11 MPAs across 6 countries on the Mediterranean Sea. To do so, we developed individual indicators f…
Defoliation effects on plant and soil properties in an experimental low arctic grassland community – the role of plant community structure
2008
In Northern Fennoscandia, sub-arctic and arctic grasslands are commonly grazed by the semi-domesticated reindeer. Reindeer grazing is known to affect plant production and belowground processes, such as nutrient mineralization in these grasslands, but little is known of the role of plant community structure in the response of plant and soil properties to the defoliation of plants. Using soil and seeds from a low arctic meadow, we established a 23-week greenhouse experiment to test whether communities of different plant species richness (one, two or four species) and composition (three different replicated compositions within each richness level) respond to defoliation in a different way. We …
Downscaling rice yield simulation at sub-field scale using remotely sensed LAI data
2019
Abstract Crop modeling and remote sensing are key tools to gain deeper understanding on cropping system dynamics and, ultimately, to increase the sustainability of agricultural productions. This study presents a system to estimate rice yields at sub-field scale based on the integration of a biophysical model and remotely sensed products. Leaf area index (LAI) data derived from decametric optical imageries (i.e., Landsat-8, Landsat-7 and Sentinel–2A) were assimilated into the WARM rice model via automatic recalibration of crop parameters at a fine spatial resolution (30 m × 30 m), targeting the lowest error between simulated and remotely sensed LAI. The performance of the system was evaluate…
Role of Soil Organisms in the Maintenance of Species-Rich Seminatural Grasslands through Mowing
2009
To preserve species-rich grasslands, management practices such as mowing are often required. Mowing is known to promote aboveground conditions that help to maintain plant species richness, but whether belowground effects are important as well is not known. We hypothesized that if mowing decreases belowground carbon transfer by reducing root mass, this will reduce the abundance and activity of soil decomposers and lead to diminished nutrient availability in soil. In grasslands, this would provide a means to mitigate the negative effects of nitrogen enrichment on plant species richness. We established experimental plots on grassland with one-third of plots growing untouched, one-third mowed o…
Alleviating Soil Acidity: Optimization of Lime and Zinc Use in Maize (Zea mays L.) Grown on Alfisols
2019
ABSTRACTSoil acidity, one of the causes of soil degradation, adversely affects phytoavailability of soil nutrients and crop growth in 50% of arable land of the world. There is a persistent need for...
Root growth and soil carbon turnover in Opuntia ficus-indica as affected by soil volume availability
2019
Abstract The aim of this study was to investigate the effect of soil volume restriction, i.e. root confinement, on below-and-above ground growth of cactus pear (Opuntia ficus-indica (L.) Mill) as well as the effect on root architecture and turnover, and soil carbon turnover. In May 2014, 1- year-old cladodes were planted in five different pots size (50, 33, 18, 9 and 5 L). Soil samples were collected from each pot and dried before SOC and δ13C determination. Roots of each plant were divided visually into three groups depending on their diameter, and then measured and weighed. Results indicated a significant effect of soil volume and sampling dates on total root length, root dry mass and δ13…
Modelling the effects of more selective trawl nets on the productivity of European hake (Merluccius merluccius) and deep-water rose shrimp (Parapenae…
2018
Single-species Gadget models were used to assess the effects of using a sorting grid mounted on the traditional trawl net used by Sicilian trawlers to exploit the deep-water rose shrimp in the Strait of Sicily. The main commercial by-catch species of this fleet is the European hake (Merluccius merluccius), often caught at sizes well below the minimum conservation reference size. Selectivity curves based on the results of an experimental survey carried out in the area using a commercial trawler equipped with an ad hoc-designed sorting grid were incorporated into single-species Gadget models to forecast the effects of changing fishery selectivity on the performance of the two stocks in terms …