Search results for "Temperate"

Monthly survival of African Sylvia warblers in a seasonally arid tropical environment

2006

Latitudinal gradients of life-history traits in animals are thought to be shaped by environmental variables. For example, it has been suggested that the increase in avian clutch size from the tropics towards the northern temperate regions is caused by a reduced survival of adult birds in the north due to increasing environmental seasonality. However, the tropical savannahs of East Africa show pronounced seasonality in resources caused by distinct rainy and dry seasons. This raises the question of whether survival and other life-history traits of birds living in these tropical savannahs are influenced by this seasonality, making them more similar to northern temperate species. We used 2-year…

Life-history of two African Sylvia warblers: low annual fecundity and long post-fledging care

2004

The investigation of factors that cause differences in life-history traits between temperate and tropical birds is often hampered by a lack of knowledge about tropical species. Even within the well-known warblers of the genus Sylvia, which include resident species from temperate and tropical regions as well as migrants, there are few data from tropical species. We investigated the breeding biology of the tropical species Sylvia lugens and S. boehmi in a 2-year study in Kenya. Both species had a clutch size of 2.0 and laid c. 3.7 clutches per year. Breeding was characterized by long incubation periods (S. lugens 14.5 days, S. boehmi 15.0 days), long nestling periods (16.0 and 12.9 days, resp…

Olfactory foraging in temperate waters: sensitivity to dimethylsulphide of shearwaters in the Atlantic Ocean and Mediterranean Sea

2014

AbstractMany procellariiforms use olfactory cues to locate food patches over the seemingly featureless ocean surface. In particular, some of them are able to detect and are attracted by dimethylsulfide (DMS), a volatile compound naturally occurring over worldwide oceans in correspondence with productive feeding areas. However, current knowledge is restricted to sub-Antarctic species, and to only one study realized under natural conditions at sea. Here, for the first time, we investigated the response to DMS in parallel in two different environments in temperate waters, the Atlantic Ocean and the Mediterranean Sea, employing Cory's (Calonectris borealis) and Scopoli's shearwaters (Calonectri…

Synopsis of Carex (Cyperaceae) from sub-Saharan Africa and Madagascar

2011

This synopsis provides a key, synonymy, lectotypification, habitat descriptions and distributions for the 81 species and six additional infraspecific taxa of Carex known from tropical and southern Africa and Madagascar. It is the first treatment of Carex including all tropical and southern temperate areas in Africa since Kukenthal's monograph of subfamily Caricoideae in 1909. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 166, 51–99.

Environmental and Biochemical Factors Controlling the in Vitro Emergence of Somatic Embryos in European Spindle Tree (Euonymus europaeus L)

2000

The European spindle tree (Euonymus europaeus L. Celastraceae) is a shrubby tree widely distributed in temperate regions of western European countries from the northern part of France to St. Petersburg and the western part of Russia. The Celastraceae comprises 55 genera, including at least 850 known species of trees and shrubs which are found in tropical and temperate regions. Various secondary metabolites are elaborated in the family including steroids, triterpenoids, sesquiterpene, peptide ore alkaloids. The spindle tree is commonly found in quickset hedges and small broad-leaved forests when the soil is deep, moist, clayey and chalky. The leaves are relatively small (3–4 cm long) simple …

Tropical Temperate Toughs over southern Africa : mechanisms and evolution in response to climate change (2010-2099)

2014

In the Southern Hemisphere, Southern Africa and the south-west Indian Ocean are one of the three preferred regions where interactions between the tropics and midlatitudes develop. This is the South Indian Convergence Zone (SICZ), where northwest-southeast oriented cloud bands form at the synoptic scale (between 3 and 5 days). These bands are mainly found during the austral summer and are commonly referred to as tropical temperate troughs (TTTs). This research aims at improving our knowledge related to TTTs, with a study on the dynamics associated with these systems, and an analysis of their possible evolution during the 21st century.The first part of this thesis aims at identifying favorabl…

Functional consequences of prey acclimation to ocean acidification for the prey and its predator

2016

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) t…

Community Turnover of Wood-Inhabiting Fungi across Hierarchical Spatial Scales

2014

For efficient use of conservation resources it is important to determine how species diversity changes across spatial scales. In many poorly known species groups little is known about at which spatial scales the conservation efforts should be focused. Here we examined how the community turnover of wood-inhabiting fungi is realised at three hierarchical levels, and how much of community variation is explained by variation in resource composition and spatial proximity. The hierarchical study design consisted of management type (fixed factor), forest site (random factor, nested within management type) and study plots (randomly placed plots within each study site). To examine how species richne…

The effect of clove oil sedation on oxygen consumption of six temperate-zone fish species

2004

Yield development of flax varieties and lines within variable environment in Latvia

2015

Flax is the multiple purpose crop cultivated in temperate region. Seeds of oil flax recently became important constituent for many industrial applications, such as pharmacy, medicine, food production <em>etc.</em> and have high prospective for use in Latvia. Understanding the underlying processes that limit seed yield in flax is major with respect to enhancing the breeding of flax for yield improvements. The aim of study was evaluated 29 flax varieties and lines (including 20 Latvian origins) plasticity of seed yield production in changeable environmental conditions. The experiment was carried out in the Agricultural Scientific Centre of Latgale on field trials over the period 2…