0000000001025853
AUTHOR
John Loehr
showing 8 related works from this author
Monitoring of ticks and tick-borne pathogens through a nationwide research station network in Finland.
2020
In 2015 a long-term, nationwide tick and tick-borne pathogen (TBP) monitoring project was started by the Finnish Tick Project and the Finnish Research Station network (RESTAT), with the goal of producing temporally and geographically extensive data regarding exophilic ticks in Finland. In the current study, we present results from the first four years of this collaboration. Ticks were collected by cloth dragging from 11 research stations across Finland in May September 2015-2018 (2012-2018 in Seili). Collected ticks were screened for twelve different pathogens by qPCR: Borrelia afzelii, Borrelia garinii, Borrelia valaisiana, Borrelia burgdorferi sensu stricto, Borrelia miyamotoi, Babesia sp…
Coat darkness is associated with social dominance and mating behaviour in a mountain sheep hybrid lineage
2008
Natural hybridization can produce novel traits when morphologically different populations hybridize, and can introduce variation in traits that become associated with sexual selection. Evidence from breeding experiments and genetic markers indicate that the great variation in coat darkness and the unique coat patterns found in Stone's sheep Ovis dalli stonei, populations, have resulted from an ancient hybridization event between thinhorn sheep, O. dalli, and bighorn sheep, O. canadensis. Behavioural evidence gathered in 2003 and 2004 in Yukon Territory, Canada, showed that higher dominance rank was correlated with increasing darkness in rams, and comparatively darker rams were seen more oft…
Evidence for cryptic glacial refugia from North American mountain sheep mitochondrial DNA
2006
The separation of populations by ice sheets into large refugia can account for much of the genetic diversity found in present day populations. The evolutionary implications of small glacial refugia have not been as thoroughly explored. To examine refugial origins of North American mountain sheep Ovis spp., we analyzed a 604 bp portion of the mitochondrial DNA (mtDNA) control region from 223 O. dalli and O. canadensis. Major refugia were identified in eastern Beringia and southern North America, and we found evidence for two smaller refugia situated between the Laurentide and Cordilleran glaciers. Our results are the first to demonstrate support for survival of any organism in the latter two…
Horn growth rate and longevity: implications for natural and artificial selection in thinhorn sheep (Ovis dalli).
2007
We used horn measurements from natural and hunted mortalities of male thinhorn sheep Ovis dalli from Yukon Territory, Canada, to examine the relationship between rapid growth early in life and longevity. We found that rapid growth was associated with reduced longevity for sheep aged 5 years and older for both the hunted and natural mortality data sets. The negative relationship between growth rate and longevity in hunted sheep can at least partially be explained by morphologically biased hunting regulations. The same trend was evident from natural mortalities from populations that were not hunted or underwent very limited hunting, suggesting a naturally imposed mortality cost directly or in…
Newly Digitized Database Reveals the Lives and Families of Forced Migrants from Finnish Karelia
2017
Studies on displaced persons often suffer from a lack of data on the long-term effects of forced migration. A register created during 1960s and published as a book series ‘Siirtokarjalaisten tie’ in 1970 documented the lives of individuals who fled the southern Karelian district of Finland after its first and second occupation by the Soviet Union in 1940 and 1944. To realize the potential value of these data for scientific research, we have recently scanned the register using optical character recognition (OCR) software, and developed proprietary computer code to extract these data. Here we outline the steps involved in the digitization process, and present an overview of the Migration Kare…
Ecology and extent of freshwater browning - What we know and what should be studied next in the context of global change
2022
Water browning or brownification refers to increasing water color, often related to increasing dissolved organic matter (DOM) and carbon (DOC) content in freshwaters. Browning has been recognized as a significant physicochemical phenomenon altering boreal lakes, but our understanding of its ecological consequences in different freshwater habitats and regions is limited. Here, we review the consequences of browning on different freshwater habitats, food webs and aquatic-terrestrial habitat coupling. We examine global trends of browning and DOM/DOC, and the use of remote sensing as a tool to investigate browning from local to global scales. Studies have focused on lakes and rivers while seldo…
Selective Fatty Acid Retention and Turnover in the Freshwater Amphipod Pallaseopsis quadrispinosa
2021
Gammarid amphipods are a crucial link connecting primary producers with secondary consumers, but little is known about their nutritional ecology. Here we asked how starvation and subsequent feeding on different nutritional quality algae influences fatty acid retention, compound-specific isotopic carbon fractionation, and biosynthesis of omega-3 and omega-6 polyunsaturated fatty acids (PUFA) in the relict gammarid amphipod Pallaseopsis quadrispinosa. The fatty acid profiles of P. quadrispinosa closely matched with those of the dietary green algae after only seven days of refeeding, whereas fatty acid patterns of P. quadrispinosa were less consistent with those of the diatom diet. This was ma…
Thinhorn sheep evolution and behaviour
2006
Miksi kaikki ohutsarvilampaat Kanadan Yukonjoen itäpuolella ovat tummia, mutta joen toisella puolella valkoisia? Minkä vuoksi tummissa populaatioissa lampaiden väri vaihtelee niin paljon? Näitä kysymyksiä John Loehr valotti väitöskirjassaan.Ohutsarvilammas on pohjoisamerikkalainen villilammaslaji, joka elää Alaskan ja Pohjois-Kanadan vuoristoissa. Laji on mielenkiintoinen värivaihtelunsa takia. Suurin osa populaatioista on täysin valkoisia, mutta kolmesta vuoristosta löytyy harmaita ja mustia lampaita. Näissä vuoristoissa lammasyksilöiden tummuusaste vaihtelee niin paljon, että Loehr pystyi tunnistamaan yksilöitä värikuvioiden avulla. Loehr tutki myös ihmisten mahdollista vaikutusta ohutsar…