Trophic resource use and partitioning in multispecies ungulate communities

Robert Spitzer

Trophic resource use and partitioning in multispecies ungulate communities

Bidragets översatta titel: Utnyttjande av födoresurser i flerartssystem av klövvilt

Robert Spitzer

Institutionen för vilt, fisk och miljö

Publikation: Avhandling › Doktorsavhandling

10 Nedladdningar

Sammanfattning

Under de senaste decennierna har stammarna av klövvilt vuxit på norra halvklotet, samtidigt som arterna utökat sina utbredningsområden. Parallellt har oron för negativa effekter av klövvilt ökat. Kunskap om hur olika klövvilt utnyttjar tillgängligt foder är central för att kunna förvalta klövviltstammar i förhållande till varandra och till jord- och skogsbruk.I den här avhandlingen har jag undersökt vad älg, rådjur, kronhjort och dovhjort äter under året i olika typer av landskap i Sverige och Europa, och hur hjortarterna påverkar varandra genom sina foderval. Jag kombinerar litteraturstudier om europeiska klövviltsdieter med egna analyser av DNA-rester i viltets spillning för att generera kunskap om foderutnyttjande i olika klövviltssamhällen. Med DNA-metoder visar jag också att bestämning av arttillhörighet vid spillningsinventeringar är svårt när djurarterna har liknande kroppsstorlek, men att det är möjligt att skilja spillning från älg och från våra mindre hjortvilt.Litteraturen visar att dieterna för Europas fyra huvudsakliga hjortvilt överensstämmer väl med Hofmanns hypotes om idisslartyper. Kron- och dovhjort (selektiva blandätare) visade större flexibilitet i sina foderval jämfört med rådjur och älg (kvistbetare). Enligt mina DNA analyser utnyttjade svenskt kron- och dovvilt en större andel vedartad växtlighet än vad de gör i Centraleuropa. Nischbredden på dieten var lägst för älg och högst för dovhjort, med liten variation mellan säsongerna. Älgens diet skiljde sig från de övriga hjortarna, som hade mer överlappande dieter. Ris av släktet Vaccinium (blåbär, lingon, odon) utgjorde en stor andel av födan för alla fyra hjortarter som undersöktes. Tall, Pinus sylvestris, utgjorde dock bara vanlig föda för älg. I områden med höga tätheter av de mindre hjortarterna åt älgen mindre Vaccinium och mer tall, medan motsvarande mönster saknades för de mindre arterna.Detta antyder att födokonkurrens kan tvinga älgen att utnyttja tall i större utsträckning och därmed orsakar större konflikter med skogsbruket. För att minska dem kan det vara mer effektivt att förvalta viktiga foderarter och de mindre hjortarna, än att enbart fokusera på att reglera älgstammen.

Bidragets översatta titel	Utnyttjande av födoresurser i flerartssystem av klövvilt
Originalspråk	Engelska
Kvalifikation	Doktor i filosofi
Förlag	Swedish University of Agricultural Sciences
Tryckta ISBN	978-91-7760-464-8
Elektroniska ISBN	978-91-7760-465-5
Status	Publicerad - 2019

Nyckelord

DNA metabarcoding
dietary overlap
dung morphometry
fallow deer Dama dama
moose Alces alces
multispecies management
red deer Cervus elaphus
resource partitioning
roe deer Capreolus capreolus
ungulates

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Acta Universitatis Agriculturae Sueciae

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title = "Trophic resource use and partitioning in multispecies ungulate communities",

abstract = "Over the past decades, ungulates across the northern hemisphere have been expanding in range and numbers. This has raised concerns about their impacts, particularly on shared resources with humans, e.g., timber trees. Understanding how different ungulate species use trophic resources is therefore a crucial component of managing their populations.In this thesis, I synthesized data from the literature and used faecal DNA metabarcoding to investigate diets and patterns of resource partitioning for ungulate communities in Sweden and at the European scale. I also evaluated the reliability of dung morphometry for identifying ungulate species. I found that species identification of faecal pellets is difficult where similar-sized ungulates coexist which questions the reliability of pellet counts as a monitoring technique in such systems. Dung morphometry could, however, clearly distinguish moose from the smaller deer species. Across Europe, average diets of the four main deer species fit well with predictions by Hofmann{\textquoteright}s hypothesis of ruminant feeding types. Red and fallow deer (mixed feeders) showed larger dietary plasticity than moose and roe deer (browsers). In Sweden, red and fallow deer adopted a more browser-like diet with high proportions of woody plant species in their diet. Dietary niche width was lowest for moose and highest for fallow deer but varied only little across seasons. Ericaceous shrubs like Vaccinium spp. comprised a major component in the diet of all four deer species. Intraspecific dietary overlap for moose was higher than dietary overlap with either of the smaller deer species. Moose diets also contained larger proportions of Scots pine Pinus sylvestris than those of the other deer species. In areas with high densities of the smaller deer, moose, but not the other deer species, consumed more pine and less Vaccinium spp. Feeding competition from the smaller deer species over Vaccinium spp. may drive moose towards increased browsing on pine, thereby exacerbating the forestry-moose conflict.For the mitigation of this conflict, managing important food items like Vaccinium spp. and the populations of smaller deer species may be of equal or greater importance than a simple reduction in the number of moose.",

keywords = "DNA metabarcoding, dietary overlap, dung morphometry, fallow deer Dama dama, moose Alces alces, multispecies management, red deer Cervus elaphus, resource partitioning, roe deer Capreolus capreolus, ungulates, DNA metabarcoding, dietary overlap, dung morphometry, fallow deer Dama dama, moose Alces alces, multispecies management, red deer Cervus elaphus, resource partitioning, roe deer Capreolus capreolus, ungulates",

author = "Robert Spitzer",

year = "2019",

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N2 - Over the past decades, ungulates across the northern hemisphere have been expanding in range and numbers. This has raised concerns about their impacts, particularly on shared resources with humans, e.g., timber trees. Understanding how different ungulate species use trophic resources is therefore a crucial component of managing their populations.In this thesis, I synthesized data from the literature and used faecal DNA metabarcoding to investigate diets and patterns of resource partitioning for ungulate communities in Sweden and at the European scale. I also evaluated the reliability of dung morphometry for identifying ungulate species. I found that species identification of faecal pellets is difficult where similar-sized ungulates coexist which questions the reliability of pellet counts as a monitoring technique in such systems. Dung morphometry could, however, clearly distinguish moose from the smaller deer species. Across Europe, average diets of the four main deer species fit well with predictions by Hofmann’s hypothesis of ruminant feeding types. Red and fallow deer (mixed feeders) showed larger dietary plasticity than moose and roe deer (browsers). In Sweden, red and fallow deer adopted a more browser-like diet with high proportions of woody plant species in their diet. Dietary niche width was lowest for moose and highest for fallow deer but varied only little across seasons. Ericaceous shrubs like Vaccinium spp. comprised a major component in the diet of all four deer species. Intraspecific dietary overlap for moose was higher than dietary overlap with either of the smaller deer species. Moose diets also contained larger proportions of Scots pine Pinus sylvestris than those of the other deer species. In areas with high densities of the smaller deer, moose, but not the other deer species, consumed more pine and less Vaccinium spp. Feeding competition from the smaller deer species over Vaccinium spp. may drive moose towards increased browsing on pine, thereby exacerbating the forestry-moose conflict.For the mitigation of this conflict, managing important food items like Vaccinium spp. and the populations of smaller deer species may be of equal or greater importance than a simple reduction in the number of moose.

AB - Over the past decades, ungulates across the northern hemisphere have been expanding in range and numbers. This has raised concerns about their impacts, particularly on shared resources with humans, e.g., timber trees. Understanding how different ungulate species use trophic resources is therefore a crucial component of managing their populations.In this thesis, I synthesized data from the literature and used faecal DNA metabarcoding to investigate diets and patterns of resource partitioning for ungulate communities in Sweden and at the European scale. I also evaluated the reliability of dung morphometry for identifying ungulate species. I found that species identification of faecal pellets is difficult where similar-sized ungulates coexist which questions the reliability of pellet counts as a monitoring technique in such systems. Dung morphometry could, however, clearly distinguish moose from the smaller deer species. Across Europe, average diets of the four main deer species fit well with predictions by Hofmann’s hypothesis of ruminant feeding types. Red and fallow deer (mixed feeders) showed larger dietary plasticity than moose and roe deer (browsers). In Sweden, red and fallow deer adopted a more browser-like diet with high proportions of woody plant species in their diet. Dietary niche width was lowest for moose and highest for fallow deer but varied only little across seasons. Ericaceous shrubs like Vaccinium spp. comprised a major component in the diet of all four deer species. Intraspecific dietary overlap for moose was higher than dietary overlap with either of the smaller deer species. Moose diets also contained larger proportions of Scots pine Pinus sylvestris than those of the other deer species. In areas with high densities of the smaller deer, moose, but not the other deer species, consumed more pine and less Vaccinium spp. Feeding competition from the smaller deer species over Vaccinium spp. may drive moose towards increased browsing on pine, thereby exacerbating the forestry-moose conflict.For the mitigation of this conflict, managing important food items like Vaccinium spp. and the populations of smaller deer species may be of equal or greater importance than a simple reduction in the number of moose.

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KW - fallow deer Dama dama

KW - moose Alces alces

KW - multispecies management

KW - red deer Cervus elaphus

KW - resource partitioning

KW - roe deer Capreolus capreolus

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