Search results for "DISCIPLINA"

Assessing cetacean surveys throughout the Mediterranean Sea: a gap analysis in environmental space

2018

Heterogeneous data collection in the marine environment has led to large gaps in our knowledge of marine species distributions. To fill these gaps, models calibrated on existing data may be used to predict species distributions in unsampled areas, given that available data are sufficiently representative. Our objective was to evaluate the feasibility of mapping cetacean densities across the entire Mediterranean Sea using models calibrated on available survey data and various environmental covariates. We aggregated 302,481 km of line transect survey effort conducted in the Mediterranean Sea within the past 20 years by many organisations. Survey coverage was highly heterogeneous geographicall…

Sporadic nesting reveals long distance colonisation in the philopatric loggerhead sea turtle (Caretta caretta)

2018

The colonisation of new suitable habitats is crucial for species survival at evolutionary scale under changing environmental conditions. However, colonisation potential may be limited by philopatry that facilitates exploiting successful habitats across generations. We examine the mechanisms of long distance dispersal of the philopatric loggerhead sea turtle (Caretta caretta) by analysing 40 sporadic nesting events in the western Mediterranean. The analysis of a fragment of the mitochondrial DNA and 7 microsatellites of 121 samples from 18 of these nesting events revealed that these nests were colonising events associated with juveniles from distant populations feeding in nearby foraging gro…

Ocean acidification drives community shifts towards simplified non-calcified habitats in a subtropical?temperate transition zone

2018

AbstractRising atmospheric concentrations of carbon dioxide are causing surface seawater pH and carbonate ion concentrations to fall in a process known as ocean acidification. To assess the likely ecological effects of ocean acidification we compared intertidal and subtidal marine communities at increasing levels of pCO2 at recently discovered volcanic seeps off the Pacific coast of Japan (34° N). This study region is of particular interest for ocean acidification research as it has naturally low levels of surface seawater pCO2 (280–320 µatm) and is located at a transition zone between temperate and sub-tropical communities. We provide the first assessment of ocean acidification effects at …

Dynamics and Impacting Factors of Ice Regimes in Latvia Inland and Coastal Waters

2016

Abstract The sea ice regime is considered to be a sensitive indicator of climate change. This study investigates long-term changes in the ice regimes of the Gulf of Riga along the coast of Latvia in comparison with those of inland waters. The ice regime of the studied region indicates the impact of climate change related to increasing air and sea water temperatures. Ice cover duration on both the sea and inland waters has decreased during recent decades. In addition, long-term records on ice break in the studied region exhibit a pattern of periodic changes in the intensity of ice regime, while trends of the sea ice regime are not consistent between periods of time. Alternating mild and seve…

A global baseline for ecosystem recovery

2016

2017

AbstractBeneficial effects of CO2 on photosynthetic organisms will be a key driver of ecosystem change under ocean acidification. Predicting the responses of macroalgal species to ocean acidification is complex, but we demonstrate that the response of assemblages to elevated CO2 are correlated with inorganic carbon physiology. We assessed abundance patterns and a proxy for CO2:HCO3− use (δ13C values) of macroalgae along a gradient of CO2 at a volcanic seep, and examined how shifts in species abundance at other Mediterranean seeps are related to macroalgal inorganic carbon physiology. Five macroalgal species capable of using both HCO3− and CO2 had greater CO2 use as concentrations increased.…

2017

The debate on the causes of conflict in human societies has deep roots. In particular, the extent of conflict in hunter-gatherer groups remains unclear. Some authors suggest that large-scale violen ...

Explaining Bird Migration

2010

Arctic shorebirds can travel tens of thousands of kilometers every year as they fly along intercontinental flyways from their southern wintering grounds to their remote, harsh breeding sites. How these birds solve the navigational and physiological constraints has been largely answered, but why they migrate is still a question with many possible answers ( 1 ). On page 326 of this issue, McKinnon et al. ( 2 ) present a continent-wide study that points to predation as a driving mechanism for migration. The study also elucidates the role of predation in shaping Arctic terrestrial biodiversity.

2016

By altering or eliminating delicate ecological relationships, non-indigenous species are con- sidered a major threat to biodiversity, as well as a driver of environmental change. Global cli- mate change affects ecosystems and ecological communities, leading to changes in the phenology, geographic ranges, or population abundance of several species. Thus, predicting the impacts of global climate change on the current and future distribution of invasive species is an important subject in macroecological studies. The African clawed frog (Xenopus laevis), native to South Africa, possesses a strong invasion potential and populations have become established in numerous countries across four contin…

Introduction and Breeding of Rhododendrons in Latvia

2017

Abstract Rhododendrons are relatively new beautiful ornamental plants in Latvia forming an essential part of public and private gardens, although they were introduced in Latvian territory already during the first half of 19th century. Rhododendrons deserve their immense popularity due to the diversity of their habitat, size and type of blossoms and leaves and their flowering season. There are about 1000 rhododendron species in the wild up to now whereas breeders in various countries have created more than 30 000 cultivars. Intensive rhododendrons introduction and acclimatization in Latvia started in 1957 when Rihards Kondratovičs, at the time director of the Botanical Garden, University of …