Search results for "Context"

The origin of two cryptic species of African desert jerboas (Dipodidae: Jaculus)

2011

The desert biota is exposed to extreme and variable conditions that shape its evolution and diversification processes. In this respect, the Jaculus jerboas have gained the attention of researchers as a result of their broad Saharan–Arabian distribution and their high and unexplained, morphological, anatomical, and molecular variation. In the present study, mitochondrial and nuclear genealogies where used to confirm monophyly of two cryptic species: Jaculus jaculus and Jaculus deserti. The reconstructed demography showed that the evolutionary histories of the species are markedly different and that the expansion into North-West Africa by J. deserti was more recent than that of J. jaculus. Th…

Resistant Microbial Cooccurrence Patterns Inferred by Network Topology

2015

ABSTRACT Although complex cooccurrence patterns have been described for microbes in natural communities, these patterns have scarcely been interpreted in the context of ecosystem functioning and stability. Here we constructed networks from species cooccurrences between pairs of microorganisms which were extracted from five individual aquatic time series, including a dystrophic and a eutrophic lake as well as an open ocean site. The resulting networks exhibited higher clustering coefficients, shorter path lengths, and higher average node degrees and levels of betweenness than those of random networks. Moreover, simulations demonstrated that taxa with a large number of cooccurrences and place…

Ocean acidification through the lens of ecological theory

2015

© 2015 by the Ecological Society of America. Ocean acidification, chemical changes to the carbonate system of seawater, is emerging as a key environmental challenge accompanying global warming and other humaninduced perturbations. Considerable research seeks to define the scope and character of potential outcomes from this phenomenon, but a crucial impediment persists. Ecological theory, despite its power and utility, has been only peripherally applied to the problem. Here we sketch in broad strokes several areas where fundamental principles of ecology have the capacity to generate insight into ocean acidification's consequences. We focus on conceptual models that, when considered in the co…

Temporal and dietary niche is context‐dependent in tropical ants

2020

Dispersal of larval and juvenile seabream: Implications for Mediterranean marine protected areas

2015

International audience; In the marine context, information about dispersal is essential for the design of networks of marine protected areas (MPAs). Generally, most of the dispersal of demersal fishes is thought to be driven by the transport of eggs and larvae in currents, with the potential contribution of dispersal in later life stages relatively minimal.Using otolith chemistry analyses, we estimate dispersal patterns across a spatial scale of approximately 180 km at both propagule (i.e. eggs and larvae) and juvenile (i.e. between settlement and recruitment) stages of a Mediterranean coastal fishery species, the two-banded seabream Diplodus vulgaris. We detected three major natal sources …

A Revision of the Nearctic Species of Hecamedoides Hendel (Diptera: Ephydridae)

2008

Abstract Species of the shore-fly genus Hecamedoides Hendel from the Nearctic Region are revised, including description of H. lattini, new species (Virginia. Stafford: Falmouth (38°19.2′N, 77°28.1′W; Rappahannock River; 9 m). To provide context and also to facilitate identification, diagnoses are provided for the tribe Discocerinini and genus in addition to a key to the genera and species, H. lattini and H. unispinosus, occurring in the New World. Diagnostic characters, especially of the male terminalia, are illustrated, and distribution maps are also provided.

Deep-sea shrimp fishery in Sicily: The economic performance of the shrimp trawling fleet in the ports of Mazara del Vallo, Sciacca, and Porto Empedoc…

2006

Shrimp fishing in Sicily is carried out by fishing companies using trawlers and multifunctional vessels equipped with trawling nets, in a complex and worrisome context, because of the decrease in catch over the last few years. After analysing the structural characteristics of Sicilian trawling, the study concentrates on the three most important shrimp fishing ports in Sicily: Mazara del Vallo, Sciacca, and Porto Empedocle. For each fleet, through a sample analysis, economic performance has been evaluated for the period from 2001 to 2003. Finally, a comparative analysis of the economic performance of the surveyed companies is carried out through a comparison of daily economic productivity in…

Placing unprecedented recent fir growth in a European-wide and Holocene-long context

2014

7 páginas.- Büntgen, U.

Overcoming the crisis : the changing profile and trajectories of Latvian migrants

2016

The work was funded by the National Research Programme [grant number 5.2.4] and the Latvian Council of Sciences [grant number 514/2012]. Taking mobility between Latvia and Western Europe as an empirical lens, this analysis explores the complex relationship between spatial disparities in earning potential and migration. The very dramatic shifts in the economic and political context against which migration from Latvia has occurred over the period 2004-2012 make it an especially apposite focus of research investigating the link between mobility and labour market circumstances. As an analytical starting point, conventional economic theory broadly explains the movement of workers from lower to h…

The quality of life of residents of a satellite degraded city district as part of urban development policy

2017

The purpose of this article is to assess the quality of life of the residents of a degraded satellite area of a city. It is considered in the context of urban development policy – as the result of decisions and as a challenge for long-term development. The research was based on a case study, which is the district of Opole referred to as Metalchem. It is characterized by an isolated location in the city structure as well as economic transformations. The study was based primarily on an analysis of source materials and results of a survey. The results show that the assessment of the quality of life is inconsistent. The living conditions are good, but satisfactory fulfilment of social needs is …