Synchronizing migration with birth: an exploration of migratory tactics in female moose
Migration and giving birth are crucial decisions for animals during their life cycle, which may have lasting consequences on their population demography and fitness. Migration can entail a variety of possible effects for an individual, such as access to high quality food and reduced risk for predati...
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| Formato: | H2 |
| Lenguaje: | Inglés sueco |
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SLU/Dept. of Wildlife, Fish and Environmental Studies
2015
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| Materias: |
| _version_ | 1855571241997434880 |
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| author | Näsén, Linnéa |
| author_browse | Näsén, Linnéa |
| author_facet | Näsén, Linnéa |
| author_sort | Näsén, Linnéa |
| collection | Epsilon Archive for Student Projects |
| description | Migration and giving birth are crucial decisions for animals during their life cycle, which may have lasting consequences on their population demography and fitness. Migration can entail a variety of possible effects for an individual, such as access to high quality food and reduced risk for predation. The moose (Alces alces) in northern Sweden is partially migratory and moose females are known to give birth to one or two calves. The synchrony between time of calving and timing of migration has not been compared before, especially in terms of energy maximizing and time minimizing perspectives, which may provide vital cues for fitness benefits of migration. I investigated effect of timing of birth and individual life history on distance, timing, stopovers and duration of 190 individually marked female moose that have been tracked for multiple years in ten different areas in northern Sweden. The effects of the life history variables (area, age, body mass, litter size) were tested by using Generalized Linear Mixed Models (GLMMs), and ANOVAs together with Turkey’s HSD tests were used to explain variation in movement between females of different reproductive status. Females that gave birth during migration had the longest duration of spring migration and used the most stopovers than others. Females that gave birth before spring migration arrived later in the summer ranges than other female groups. However, those that gave birth after spring migration had the quickest spring migrations. Younger females migrated earlier in autumn than older females and females with twins migrated earlier during autumn than other female groups. Such timing adjustments between migration and reproduction demonstrate that the time minimizing versus energy maximizing behavioural trade-offs can exist within a species, where individuals make trade-offs depending upon their life history and life cycle events. |
| format | H2 |
| id | RepoSLU7779 |
| institution | Swedish University of Agricultural Sciences |
| language | Inglés swe |
| publishDate | 2015 |
| publishDateSort | 2015 |
| publisher | SLU/Dept. of Wildlife, Fish and Environmental Studies |
| publisherStr | SLU/Dept. of Wildlife, Fish and Environmental Studies |
| record_format | eprints |
| spelling | RepoSLU77792015-03-31T14:21:17Z Synchronizing migration with birth: an exploration of migratory tactics in female moose Synkronisering av migration och födsel: en undersökning av migrationstaktiker hos älghonor Näsén, Linnéa migration calving moose time minimization energy maximization Migration and giving birth are crucial decisions for animals during their life cycle, which may have lasting consequences on their population demography and fitness. Migration can entail a variety of possible effects for an individual, such as access to high quality food and reduced risk for predation. The moose (Alces alces) in northern Sweden is partially migratory and moose females are known to give birth to one or two calves. The synchrony between time of calving and timing of migration has not been compared before, especially in terms of energy maximizing and time minimizing perspectives, which may provide vital cues for fitness benefits of migration. I investigated effect of timing of birth and individual life history on distance, timing, stopovers and duration of 190 individually marked female moose that have been tracked for multiple years in ten different areas in northern Sweden. The effects of the life history variables (area, age, body mass, litter size) were tested by using Generalized Linear Mixed Models (GLMMs), and ANOVAs together with Turkey’s HSD tests were used to explain variation in movement between females of different reproductive status. Females that gave birth during migration had the longest duration of spring migration and used the most stopovers than others. Females that gave birth before spring migration arrived later in the summer ranges than other female groups. However, those that gave birth after spring migration had the quickest spring migrations. Younger females migrated earlier in autumn than older females and females with twins migrated earlier during autumn than other female groups. Such timing adjustments between migration and reproduction demonstrate that the time minimizing versus energy maximizing behavioural trade-offs can exist within a species, where individuals make trade-offs depending upon their life history and life cycle events. Migration och födsel av kalvar är viktiga händelser för djur under livstiden, händelser som varaktigt kan påverka populationens sammansättning och fitness. Migration kan ge en rad positiva effekter för den enskilda individen, så som tillgång till föda med högre näringsvärde och minskad risk för predation. Älgpopulationen (Alces alces) i norra Sverige är delvis migrerande och det är känt att älgkor föder en till två kalvar. Synkroniseringen mellan födsel av kalv och migration har aldrig jämförts tidigare, speciellt inte i termer av energimaximering och tidsminimering, vilket kan ge viktiga insikter om hur individens fitness påverkas av migration. Jag undersökte hur effekten av tidpunkt för födsel av kalv påverkar distans, timing, uppehåll och varaktighet för 190 individuellt märkta älgkor som följts under flertalet år i tio olika områden in norra Sverige. Effekterna av livshistorievariablerna (område, ålder, vikt, kullstorlek) testades genom att använda Generalized Linear Mixed Models (GLMMs), och ANOVAs tillsammans med Tukey’s HSD test användes för att förklara variation i rörelse mellan älgkor av olika reproduktiv status. Kor som födde kalven under migrationen hade den längsta vårmigrationen och stannade flest gånger under migrationen. Kor som födde kalven innan vårmigrationen anlände senare till sommarområdet än de andra grupperna av kor. Däremot hade de älgkor som födde kalven efter vårmigrationen de snabbaste vårmigrationerna. Yngre älgkor migrerade tidigare under hösten än vad äldre älgkor gjorde och älgkor med två kalvar migrerade tidigare under hösten än andra grupper av älgkor. Sådana tidsjusteringar mellan migration och födsel av kalv visar att avvägningar mellan tidsminimeringsstrategin kontra energimaximeringsstrategin kan existera inom en art, där individer gör avvägningar beroende på deras livshistoria och livscykelhändelser. SLU/Dept. of Wildlife, Fish and Environmental Studies 2015 H2 eng swe https://stud.epsilon.slu.se/7779/ |
| spellingShingle | migration calving moose time minimization energy maximization Näsén, Linnéa Synchronizing migration with birth: an exploration of migratory tactics in female moose |
| title | Synchronizing migration with birth: an exploration of migratory tactics in female moose |
| title_full | Synchronizing migration with birth: an exploration of migratory tactics in female moose |
| title_fullStr | Synchronizing migration with birth: an exploration of migratory tactics in female moose |
| title_full_unstemmed | Synchronizing migration with birth: an exploration of migratory tactics in female moose |
| title_short | Synchronizing migration with birth: an exploration of migratory tactics in female moose |
| title_sort | synchronizing migration with birth: an exploration of migratory tactics in female moose |
| topic | migration calving moose time minimization energy maximization |