862 resultados para Availability of prey
Resumo:
Correct species identifications are of tremendous importance for invasion ecology, as mistakes could lead to misdirecting limited resources against harmless species or inaction against problematic ones. DNA barcoding is becoming a promising and reliable tool for species identifications, however the efficacy of such molecular taxonomy depends on gene region(s) that provide a unique sequence to differentiate among species and on availability of reference sequences in existing genetic databases. Here, we assembled a list of aquatic and terrestrial non-indigenous species (NIS) and checked two leading genetic databases for corresponding sequences of six genome regions used for DNA barcoding. The genetic databases were checked in 2010, 2012, and 2016. All four aquatic kingdoms (Animalia, Chromista, Plantae and Protozoa) were initially equally represented in the genetic databases, with 64, 65, 69, and 61% of NIS included, respectively. Sequences for terrestrial NIS were present at rates of 58 and 78% for Animalia and Plantae, respectively. Six years later, the number of sequences for aquatic NIS increased to 75, 75, 74, and 63% respectively, while those for terrestrial NIS increased to 74 and 88% respectively. Genetic databases are marginally better populated with sequences of terrestrial NIS of plants compared to aquatic NIS and terrestrial NIS of animals. The rate at which sequences are added to databases is not equal among taxa. Though some groups of NIS are not detectable at all based on available data - mostly aquatic ones - encouragingly, current availability of sequences of taxa with environmental and/or economic impact is relatively good and continues to increase with time.
Resumo:
Ocean acidification is the suite of chemical changes to the carbonate system of seawater as a consequence of anthropogenic carbon dioxide (CO2) emissions. Despite a growing body of evidences demonstrating the negative effects of ocean acidification on marine species, the consequences at the ecosystem level are still unclear. One factor limiting our ability to upscale from species to ecosystem is the poor mechanistic understanding of the functional consequences of the observed effects on organisms. This is particularly true in the context of species interactions. The aim of this work was to investigate the functional consequence of the exposure of a prey (the mussel Brachidontes pharaonis) to ocean acidification for both the prey and its predator (the crab Eriphia verrucosa). Mussels exposed to pH 7.5 for >4 weeks showed significant decreases in condition index and in mechanical properties (65% decrease in maximum breaking load) as compared with mussels acclimated to pH 8.0. This translated into negative consequences for the mussel in presence of the predator crab. The crab feeding efficiency increased through a significant 27% decrease in prey handling time when offered mussels acclimated to the lowest pH. The predator was also negatively impacted by the acclimation of the prey, probably as a consequence of a decreased food quality. When fed with prey acclimated under decreased pH for 3 months, crab assimilation efficiency significantly decreased by 30% and its growth rate was 5 times slower as compared with crab fed with mussels acclimated under high pH. Our results highlight the important to consider physiological endpoints in the context of species interactions.
Resumo:
Spatial data are being increasingly used in a wide range of disciplines, a fact that is clearly reflected in the recent trend to add spatial dimensions to the conventional social sciences. Economics is by no means an exception. On one hand, spatial data are indispensable to many branches of economics such as economic geography, new economic geography, or spatial economics. On the other hand, macroeconomic data are becoming available at more and more micro levels, so that academics and analysts take it for granted that they are available not only for an entire country, but also for more detailed levels (e.g. state, province, and even city). The term ‘spatial economics data’ as used in this report refers to any economic data that has spatial information attached. This spatial information can be the coordinates of a location at best or a less precise place name as is used to describe administrative units. Obviously, the latter cannot be used without a map of corresponding administrative units. Maps are therefore indispensible to the analysis of spatial economic data without absolute coordinates. The aim of this report is to review the availability of spatial economic data that pertains specifically to Laos and academic studies conducted on such data up to the present. In regards to the availability of spatial economic data, efforts have been made to identify not only data that has been made available as geographic information systems (GIS) data, but also those with sufficient place labels attached. The rest of the report is organized as follows. Section 2 reviews the maps available for Laos, both in hard copy and editable electronic formats. Section 3 summarizes the spatial economic data available for Laos at the present time, and Section 4 reviews and categorizes the many economic studies utilizing these spatial data. Section 5 give examples of some of the spatial industrial data collected for this research. Section 6 provides a summary of the findings and gives some indication of the direction of the final report due for completion in fiscal 2010.
Resumo:
Adding Zn improves crop growth, increases seed yield and also positively affects nutritional quality. After Zn fertilization, there is normally a period of several years in which residual effects provide an adequate supply of Zn to successive crops. Immediately after the application of Zn sources water-soluble Zn slowly but continually decreases. Various factors, including time and moisture conditions, affect the aging process and modify the solubility of the metal in soil and therefore its availability. In previous experiments, we studied the residual effect of synthetic chelates, obtained that the amounts of potentially available Zn decreased in the second cropping year due to aging processes. The present study was undertaken to verify variations in the residual effects of applying four different synthetic Zn sources
Resumo:
We show a cluster based routing protocol in order to improve the convergence of the clusters and of the network it is proposed to use a backup cluster head. The use of a event discrete simulator is used for the implementation and the simulation of a hierarchical routing protocol called the Backup Cluster Head Protocol (BCHP). Finally it is shown that the BCHP protocol improves the convergence and availability of the network through a comparative analysis with the Ad Hoc On Demand Distance Vector (AODV)[1] routing protocol and Cluster Based Routing Protocol (CBRP)[2]