Search results for "Population decline"
showing 7 items of 17 documents
BORRELIA BURGDORFERI SENSU LATO DETECTED IN SKIN OF NORWEGIAN MOUNTAIN HARES (LEPUS TIMIDUS) WITHOUT SIGNS OF DISSEMINATION
2011
The mountain hare (Lepus timidus) population in southern Norway appears to be in decline. Necropsy and laboratory examinations of 36 hares found dead or diseased during 2007-2009 in Vest- and Aust-Agder counties showed that disease and deaths were attributed to multiple causes, with no specific etiology emerging as a cause for population decline. To investigate whether Borrelia burgdorferi sensu lato (s.l.) infection is associated with mortality in mountain hares, tissues and ticks collected from hares were investigated for infection with the spirochete. Borrelia burgdorferi s.l. DNA was not detected in samples from internal organs, whereas Borrelia afzelii, B. burgdorferi sensu stricto (s.…
Iedzīvotāju skaita samazināšanās un jauniešu emigrācija Latvijā un Lietuvā
2018
Maģistra darba mērķis ir aprakstīt un analizēt demogrāfiskās tendences iedzīvotāju migrācijā, novecošanā, populācijas sarukšanā, intelektuālā darbaspēka emigrācijā un izvērtēt šos kritērijus Lietuvā un Latvijā. Kādas ir dažādo demogrāfisko parādību definīcijas un to atšķirības un kā tās tiek pielietotas Lietuvā un Latvijā salīdzinājumā ar pārējo pasauli un Eiropas Savienību? Un kāda ir Lietuvas un Latvijas jaunatnes motivācija dzīvot, strādāt un veidot ģimenes savā dzimtenē? Ko veicina augsts negatīvās migrācijas, iedzīvotāju skaita samazināšanās un novecošanas rādītājs Lietuvā un Latvijā un kāpēc tas ir tik svarīgs jautājums? Darbā tiks analizēti notikumi no 90. gadu sākuma līdz mūsdienām …
Contextualising the Last Survivors: Population Structure of Marine Turtles in the Dominican Republic.
2013
Nesting by three species of marine turtles persists in the Dominican Republic, despite historic threats and long-term population decline. We conducted a genetic survey of marine turtles in the Dominican Republic in order to link them with other rookeries around the Caribbean. We sequenced a 740bp fragment of the control region of the mitochondrial DNA of 92 samples from three marine turtle species [hawksbill (n = 48), green (n = 2) and leatherback (n = 42)], and incorporated published data from other nesting populations and foraging grounds. The leatherback turtle (Dermochelys coriacea) in the Dominican Republic appeared to be isolated from Awala-Yalimapo, Cayenne, Trinidad and St. Croix bu…
Abrupt Alnus population decline at the end of the first millennium CE in Europe - The event ecology, possible causes and implications
2019
The study, based on the examination of 70 published and unpublished pollen profiles from Poland and supplementary data from the surrounding regions, shows that an abrupt, episodic Alnus population decline at the end of the first millennium CE was a much more widespread event than has been previously reported, spanning large areas of the temperate and boreal zones in Europe. The data from Poland suggest that the decline was roughly synchronous and most likely occurred between the 9th and 10th centuries, with strong indications for the 10th century. The pollen data indicate that human impacts were not a major factor in the event. Instead, we hypothesize that one or a series of abrupt climatic…
Population Decline of the Capercaillie Tetrao urogallus aquitanicus in the Central Pyrenees
2020
El seguimiento a largo plazo de las aves amenazadas es esencial para estimar las tendencias poblacionales e identificar las posibles causas de declive, siendo particularmente importante en el caso de las aves alpinas que habitan en areas montanosas en los limites de su area de distribucion. Analizamos la tendencia poblacional del urogallo en los Pirineos centrales espanoles a partir de investigaciones realizadas entre 2000 y 2017. Encontramos un declive significativo de la poblacion (alrededor del 58%) en el numero de aves contadas en las areas de exhibicion (lek). la mayoria de los urogallos habitan bosques de coniferas de pino negro con una cobertura elevada de arandano y rododendro en el…
Residential Change and Socio-demographic Challenges for Large Housing Estates in Riga, Latvia
2019
Large housing estates from the socialist era are a characteristic feature of the built environment in the cities of Central and Eastern Europe. Many urban researchers are increasingly interested in residential changes in these areas, showing how demographic and socioeconomic processes interact with the decline or upgrading of this distinct type of housing. In Europe, the debate concerning large housing estates is largely related to a declining and ageing population, as well as to housing conditions. In Latvia, the underdeveloped housing market and the massive privatisation of the housing stock to sitting tenants have contributed, since the late-Soviet period, to inherited socio-spatial stru…
Mechanisms of population declines in boreal forest grouse
2007
Gilbert Ludwig tutki väitöskirjassaan, miksi kanalinnut ovat vähentyneet talousmetsissä. Suomen metsäkanalintukannat ovat vähentyneet merkittävästi viimeisen 40 vuoden ajan. Pesiin ja poikasiin kohdistuvaa saalistusta on pidetty tärkeimpänä syynä kanalintukantojen laskuun. Hakkuiden ja nuorten metsien osuuden lisääntymisen on katsottu lisänneen myyräkantoja ja niitä syöviä petoja, kuten kettuja, lisäten näin myös kanalintujen pesiin ja poikasiin kohdistuvaa saalistusta. Vuosikymmenten aikana laskenut poikastuotto on keskeisessä roolissa kanalintukantojen laskussa. - Ainakaan teerellä vuotuinen aikuiskuolleisuus ei ole lainkaan lisääntynyt. Hengissäsäilyminen on päinvastoin jopa parantunut, …