Synchrony between caribou calving and plant phenology in depredated and non-depredated populations

2003 ◽  
Vol 81 (10) ◽  
pp. 1709-1714 ◽  
Author(s):  
Eric Post ◽  
Pernille Sporon Bøving ◽  
Christian Pedersen ◽  
Megan A MacArthur
Keyword(s):  
Rangifer Tarandus ◽  
Daily Basis ◽  
Plant Phenology ◽  
River Population ◽  
Large Herbivores ◽  
West Greenland ◽  
Forage Plant ◽  
Forage Plants ◽  
Study Sites ◽  
Two Populations

Two main hypotheses have been proposed to explain reproductive synchrony exhibited by many species of large herbivores: the predation hypothesis and the seasonality hypothesis. Although examples supporting both hypotheses have been presented, no study has compared the intraseasonal progression of parturition and plant phenology in depredated and non-depredated populations of large herbivores. We monitored, on a daily or near-daily basis, the progression of the caribou (Rangifer tarandus) calving seasons in two populations: the Caribou River population in Alaska, U.S.A., where predators of caribou are present and the Kangerlussuaq-Sisimiut population in West Greenland where such predators have been absent for approximately 4000 years. Simultaneously, we quantified directly the phenological progression of caribou forage plants on spatially replicated plots in both study sites. Parturition was significantly more synchronous in the West Greenland (predator-free) population than in the Alaskan (depredated) population. Progression of the calving seasons in both populations was highly synchronized to the progression of forage plant phenology, and the slopes of these relationships were statistically indistinguishable, with 50% of births having occurred when approximately 60%–70% of forage plant species were emergent. These results document clear synchronization of the timing of parturition by caribou to plant phenology, regardless of predation pressure.

Physical and reproductive characteristics of an expanding woodland caribou population (Rangifer tarandus caribou) in northern Labrador

1981 ◽  
Vol 59 (10) ◽  
pp. 1929-1940 ◽  
Author(s):  
G. R. Parker
Keyword(s):  
Rangifer Tarandus ◽  
Adult Mortality ◽  
Lean Body Weight ◽  
High Survival ◽  
Rangifer Tarandus Caribou ◽  
River Population ◽  
Female Ratio ◽  
Reproductive Maturity ◽  
Fat Reserves ◽  
George River

One hundred and fifty-nine caribou (Rangifer tarandus caribou) were collected from the area of precalving distribution of the George River population in northern Labrador between April 3 and 15, 1980. The sample revealed that caribou of northern Labrador reach physical and reproductive maturity earlier than most other free-ranging caribou populations in North America. Females attained mature values for lean body weight and shoulder height by 34 months and for total body length, heart girth, and mandible length by 46 months. Pregnancy rates for females 22, 34, and 46 months and older were 43, 90, and 95%, respectively. Measurements of fat reserves showed George River females to be in superior physical condition during spring migration than caribou on mainland Northwest Territories. Fat reserves, however, were substantially less than comparable values for females collected from the same population in March, 1976. The calf: pregnant female ratio was 42:100, suggesting a 1st year rate of mortality of approximately 58%. The most common internal parasites were Cysticercus tenuicollis and Fascioloides magna. It is concluded that the recent growth of the George River population has resulted from early female physical and reproductive maturity, low adult mortality, and high survival of calves.

scholarly journals The nitrogen window for arctic herbivores: plant phenology and protein gain of migratory caribou ( Rangifer tarandus )

Ecosphere ◽  
2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Perry S. Barboza ◽  
Lindsay L. Van Someren ◽  
David D. Gustine ◽  
M. Syndonia Bret‐Harte
Keyword(s):  
Rangifer Tarandus ◽  
Plant Phenology

scholarly journals Antler possession by west Greenland female caribou in relation to population characteristics

Rangifer ◽  
1986 ◽  
Vol 6 (2) ◽  
pp. 297 ◽  
Author(s):  
Henning Thing ◽  
Carsten Riis Olesen ◽  
Peter Aastrup
Keyword(s):  
Rangifer Tarandus ◽  
Reproductive Rate ◽  
Population Characteristics ◽  
Relative Importance ◽  
West Greenland ◽  
Winter Range ◽  
Factors Influencing ◽  
Summer Mortality ◽  
Close Relationship ◽  
Antler Development

The frequency of antlerless adult female caribou (Rangifer tarandus groenlandicus) was studied in four separate populations in west Greenland. Between the herds antlerlessness varied from 21% to 79%. An inverse relationship between winter range quality and percentage of unantlered cows is demonstrated. Relationship between calf percentage and maternal antler status was studied in one population and antlerless cows showed higher reproductive rate than antlered ones. In another population antlerless cows were almost absent outside the calving area. Calves of antlerless mothers were more susceptible to diseases and had significantly higher summer mortality than other calves, 42% and 27% respectively. The relative importance of factors influencing antler development under various environmental conditons are assessed and a close relationship between antlerlessness, physical condition, lactation, and length of period between calving and midsummer is discussed.

scholarly journals Chronic temperature stress effects on the liver proteome of two threespine stickleback (Gasterosteus aculeatus) populations using a novel DIA assay library

2021 ◽  
Author(s):  
Bryn Bo Levitan ◽  
Dietmar Kültz
Keyword(s):  
Temperature Stress ◽  
Gasterosteus Aculeatus ◽  
Functional Enrichment ◽  
River Population ◽  
Klamath River ◽  
Data Independent Acquisition ◽  
Threespine Sticklebacks ◽  
Liver Proteome ◽  
And Control ◽  
Two Populations

A data-independent acquisition (DIA) assay library was generated for the liver of threespine sticklebacks to evaluate alterations in protein abundance and functional enrichment of molecular pathways following either chronic warm (25°C) or cold (7°C) three-week temperature challenge in two estuarine populations. The DIA assay library was created from a data-dependent acquisition (DDA) based raw spectral library that was filtered to remove low quality or ambiguous peptides. Functional enrichment analyses using STRING identified larger networks that were significantly enriched by examining both the entire liver proteome and only significantly elevated or depleted proteins from the various comparisons. These systems level analyses revealed the unique liver proteomic signatures of two populations of threespine sticklebacks acclimated to chronic temperature stress. The Big lagoon population (BL) had a stronger response than the Klamath river population (KL). At 7°C, BL showed alterations in protein homeostasis that likely fueled a higher demand for energy, but both populations successfully acclimated to this temperature. The warm acclimation induced major increases in proteins involved in chromatin structure and transcription, while there were decreases in proteins related to translation and fatty acid metabolism. Functional enrichment analyses of the entire liver proteome uncovered differences in glycolysis and carbohydrate metabolism between the two populations and between the cold acclimated and control groups. We conclude that the synchronous regulatory patterns of many proteins observed in the liver of threespine sticklebacks provide more comprehensive insight into population-specific responses to thermal stress than the use of less specific pre-determined biomarkers.

Grazing kangaroos act as local recyclers of energy on semiarid floodplains

2010 ◽  
Vol 58 (3) ◽  
pp. 145 ◽  
Author(s):  
Jordan Iles ◽  
Jeff Kelleway ◽  
Tsuyoshi Kobayashi ◽  
Debashish Mazumder ◽  
Lisa Knowles ◽  
...  
Keyword(s):  
Stable Carbon Isotope ◽  
C4 Grasses ◽  
Carbon Stable Isotope ◽  
Stable Carbon ◽  
Large Herbivores ◽  
Feeding Site ◽  
Isotope Signature ◽  
Close Study ◽  
The Difference ◽  
Study Sites

On Australian semiarid floodplains, large herbivores such as kangaroos have a role in the cycling of energy (carbon) through the mechanism of feeding and defaecation of vegetative material. The degree to which kangaroos are vectors of energy within this system is not fully understood. This study describes the stable carbon isotope signature of floodplain plants and kangaroo scats at two close study sites. Kangaroos were found to deposit scats that mirrored the forage composition at each particular feeding site. Scats were 3.94‰ higher in δ13C values at the site where C4 grasses were available, indicating that this grass contributed ~25–30% of the diet of these kangaroos. The difference in diet due to the relative availability of C3 and C4 forage, detectable in the carbon stable isotope signature of scats, is used to demonstrate that kangaroos are recycling and redistributing energy locally, rather than transporting it more broadly across the floodplain.

scholarly journals Sanitary analysis, transmission and pathogenicity of fungi associated with forage plant seeds in tropical regions of Brazil

2014 ◽  
Vol 36 (1) ◽  
pp. 54-62 ◽  
Author(s):  
Gil Rodrigues dos Santos ◽  
Paulo Henrique Tschoeke ◽  
Luciana de Godoi Silva ◽  
Marcela Cristina Agustini Carneiro da Silveira ◽  
Higor Barbosa Reis ◽  
...  
Keyword(s):  
Plant Diseases ◽  
Pathogenic Potential ◽  
Tropical Regions ◽  
Forage Plant ◽  
Plant Seeds ◽  
Forage Plants ◽  
The World ◽  
Forage Species ◽  
Major Producer ◽  
Made In

Brazil is a major producer and exporter of beef in the world, 90% of the production is made in pasture and 85% of cultivated pastures in the country are Brachiaria sp. With a growing livestock industry in the recent years, several forage plant diseases became significant importance for causing losses in pasture productivity and quality. This study aims at quantifying the species of fungi associated with seeds and their frequency in forage plants from tropical regions of Brazil. Assays were performed considering: incidence, pathogenicity and seed-seedling transmission of fungi associated with seeds. Therefore, 28 lots of forage species seeds produced in the harvest of 2010-2011 were used. Fourteen genera of fungi associated with seeds were found, among which Bipolaris sp., Phoma sp., and Curvularia sp. had pathogenic potential. It was possible to note that Bipolaris sp., is prejudicial to forage seedlings of Brachiaria, Panicum and Crotalaria. Bipolaris sp. and Curvularia sp. have an average of seed-seedling transmission of 100% and 90%, respectively.

scholarly journals Warming, plant phenology and the spatial dimension of trophic mismatch for large herbivores

2008 ◽  
Vol 275 (1646) ◽  
pp. 2005-2013 ◽  
Author(s):  
Eric Post ◽  
Christian Pedersen ◽  
Christopher C Wilmers ◽  
Mads C Forchhammer
Keyword(s):  
Spatial Dimension ◽  
Plant Phenology ◽  
Large Herbivores ◽  
Trophic Mismatch

Population status, distribution, and movements of woodland caribou in west central Alberta

1988 ◽  
Vol 66 (4) ◽  
pp. 817-826 ◽  
Author(s):  
E. Janet Edmonds
Keyword(s):  
Rangifer Tarandus ◽  
Adult Mortality ◽  
Population Based ◽  
Population Status ◽  
Woodland Caribou ◽  
Winter Range ◽  
West Central ◽  
The Face ◽  
Two Populations ◽  
Maximum Estimate

Twenty-four woodland caribou (Rangifer tarandus caribou) in the mountains and foothills of west central Alberta were radio collared to obtain information on seasonal movements, location and extent of seasonal ranges, rutting and calving areas, and population status. The study was conducted from December 1979 to June 1984 (fall composition surveys continued to 1986). Two populations of woodland caribou resided in the foothills winter range: a migratory mountain variety that moved west to the mountains in spring and returned in fall, and a more sedentary woodland variety that remained year round in the forested foothills. Calving and rutting grounds of the two populations were widely separated (minimum of 60 km). The mountain population ranged over a much larger area (11 000 km2) than the woodland population (4000 km2). Woodland caribou were fewer (maximum estimate 50) than the mountain caribou (maximum estimate 200). Population sex–age structure of the mountain caribou population, based on six surveys during the rut (October), averaged 54 males: 100 females: 27 calves (15% calves). Annual minimum adult mortality was 22% for the mountain and woodland populations, and both populations appeared to be declining. Predation, primarily by wolves, was strongly implicated in adult mortality, but causes of calf mortality were not determined. Human-caused mortality was an additional factor. Intensive management is required to ensure the viability of these caribou populations in the face of increasing industrial and recreational development. A short-term wolf reduction program and long-term public education, law enforcement, and habitat protection programs are recommended.

scholarly journals Comparative response of Rangifer tarandus and other northern ungulates to climatic variability

Rangifer ◽  
2002 ◽  
Vol 22 (1) ◽  
pp. 33 ◽  
Author(s):  
Robert B. Weladji ◽  
David R. Klein ◽  
Øystein Holand ◽  
Atle Mysterud
Keyword(s):  
Life History ◽  
Life History Traits ◽  
Rangifer Tarandus ◽  
Climatic Variability ◽  
Environmental Stochasticity ◽  
Related Factor ◽  
Population Parameters ◽  
Weather Variables ◽  
Climatic Effects ◽  
Large Herbivores

To understand the factors influencing life history traits and population dynamics, attention is increasingly being given to the importance of environmental stochasticity. In this paper, we review and discuss aspects of current knowledge concerning the effect of climatic variation (local and global) on population parameters of northern ungu¬lates, with special emphasis on reindeer/caribou (Rangifer tarandus). We also restrict ourselves to indirect effects of climate through both forage availability and quality, and insect activity. Various authors have used different weather variables; with sometime opposite trends in resulting life history traits of ungulates, and few studies show consistent effects to the same climatic variables. There is thus little consensus about which weather variables play the most sig¬nificant role influencing ungulate population parameters. This may be because the effects of weather on ungulate pop¬ulation dynamics and life history traits are scale dependent and it is difficult to isolate climatic effects from density dependent factors. This confirms the complexity of the relationship between environment and ecosystem. We point out limits of comparability between systems and the difficulty of generalizing about the effect of climate change broadly across northern systems, across species and even within species. Furthermore, insect harassment appears to be a key climate-related factor for the ecology of reindeer/caribou that has been overlooked in the literature of climatic effects on large herbivores. In light of this, there is a need for further studies of long time series in assessing effects of climate variability on reindeer/caribou.

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