Responses of tree-associated species to forest management

Åsa Ranlund

Responses of tree-associated species to forest management

Åsa Ranlund

Institutionen för ekologi

Publikation: Avhandling › Doktorsavhandling

9 Nedladdningar

Sammanfattning

Många organismer i skogar är beroende av träd. När skogar brukas förändras miljön för arterna och mycket av deras habitat går förlorat. I boreala skogar är kalhuggning vanligt och med ökad efterfrågan på biobränsle så har uttaget av trädtoppar, grenar och stubbar ökat. Samtidigt så sparas en del träd av naturvårdshänsyn i de öppna miljöer som bildas efter kalhuggning. I de svenska boreala skogarna är trädartrikedomen låg men artrikedomen av växter, djur och svampar kopplad till träden är hög. Jag har analyserat hur epifytiska lavar svarar på den miljöförändring som uppstår på kvarlämnade träd när den omgivande skogen huggs ner. Jag har också analyserat hur skalbaggar i död ved påverkas av att stubbrytning sker i det omgivande landskapet. Det är generellt stor variation i hur arter svarar på skogsbruksåtgärder och det kan därför vara svårt att förutse vilka arter som kommer att påverkas negativt. I vissa fall kan trädens egenskaper, till exempel deras successionsstrategi, bidra till att det går att förutse hur arter kopplade till träden svarar på en miljöförändring. I andra fall kan arternas egna egenskaper avgöra hur de svarar på miljöförändringen. För lavar så är arter kopplade till gran, ett sekundärträd i successionen, vanligare på träd inne i skog än träd sparade på hyggen. För lavar kopplade till pionjärträden asp, björk och tall, så är mönstret det motsatta, dvs. de är vanligare på hyggesträd än på träd i skog. En del egenskaper hos lavar kan också påverka hur de svarar på den mer öppna miljö som bildas runt träd som lämnats vid avverkning. Solskydd i lavbålen, en förmåga att reproducera sig asexuellt och ett växtsätt som blad- eller busklav verkar vara egenskaper som ökar sannolikheten att en lav förekommer på hyggesträd. Hur skalbaggar påverkas av stubbskörd i landskapet varierar också stort mellan arter men predatorer verkar påverkas mer negativt än andra arter. För att belysa fler aspekter av hur arter svarar på förändring så föreslår jag att konceptet responsdiversitet utvecklas. Arter som skiljer sig i sina svar på skogsbruk ställer olika krav på naturvårdsåtgårder.

Originalspråk	Engelska
Kvalifikation	Doktor i filosofi
Förlag	Swedish University of Agricultural Sciences
Tryckta ISBN	978-91-7760-010-7
Elektroniska ISBN	978-91-7760-011-4
Status	Publicerad - 2017

Nyckelord

Bayesian hierarchical models
biodiversity
community ecology
epiphytic lichens
forest ecology
response diversity
saproxylic beetles
species models
stump harvest
tree retention

SLU-serie

Acta Universitatis Agriculturae Sueciae

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title = "Responses of tree-associated species to forest management",

abstract = "In forests there are many organisms that depend on trees. When forests are managed the environment for tree-associated species changes, and a lot of their habitat is lost. In boreal forests it is common with clearcutting, where almost all trees are harvested. In addition, with an increased demand for biofuel, the extraction of tree tops, branches and stumps is expanding. At the same time, some trees are retained in the open conditions after clearcutting for conservation purposes. In the boreal forests of Sweden, tree species richness is poor but the richness of flora and fauna of species associated with trees is high. I have analyzed the responses of epiphytic lichens to the environmental change on retained trees when the surrounding forest is clearcut. I have also analyzed the responses of saproxylic beetles to stump extraction in the landscape. Overall, there is a wide variety of species responses, and they can be difficult to predict. Sometimes tree traits, such as successional strategy, can help predict the responses of tree-associated species to environmental change. Sometimes the traits of the tree-associated species themselves can drive their response to environmental change. For lichens, species associated with the late-successional Norway spruce occur less on trees retained at clearcuts than on trees in closed-canopy forest. The pattern is the opposite for lichen species associated with early-successional tree species. Some lichen traits can also drive species responses to the open environment after clearcutting; characteristics that seem to increase the probability of lichens to occur on trees retained at clearcutting are a foliose or fruticose growth form, thallus sunscreen, or asexual reproduction. The responses of saproxylic beetles to landscape stump extraction varies, with predators more negatively affected than lower trophic levels. In an attempt to elucidate different aspects of the distribution of responses, I suggest ways to develop the concept of response diversity. The diverging responses of species to forest management entails different requirements for their conservation.",

keywords = "Bayesian hierarchical models, biodiversity, community ecology, epiphytic lichens, forest ecology, response diversity, saproxylic beetles, species models, stump harvest, tree retention, Bayesian hierarchical models, biodiversity, community ecology, epiphytic lichens, forest ecology, response diversity, saproxylic beetles, species models, stump harvest, tree retention",

author = "{\AA}sa Ranlund",

year = "2017",

language = "English",

isbn = "978-91-7760-010-7",

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publisher = "Swedish University of Agricultural Sciences",

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N2 - In forests there are many organisms that depend on trees. When forests are managed the environment for tree-associated species changes, and a lot of their habitat is lost. In boreal forests it is common with clearcutting, where almost all trees are harvested. In addition, with an increased demand for biofuel, the extraction of tree tops, branches and stumps is expanding. At the same time, some trees are retained in the open conditions after clearcutting for conservation purposes. In the boreal forests of Sweden, tree species richness is poor but the richness of flora and fauna of species associated with trees is high. I have analyzed the responses of epiphytic lichens to the environmental change on retained trees when the surrounding forest is clearcut. I have also analyzed the responses of saproxylic beetles to stump extraction in the landscape. Overall, there is a wide variety of species responses, and they can be difficult to predict. Sometimes tree traits, such as successional strategy, can help predict the responses of tree-associated species to environmental change. Sometimes the traits of the tree-associated species themselves can drive their response to environmental change. For lichens, species associated with the late-successional Norway spruce occur less on trees retained at clearcuts than on trees in closed-canopy forest. The pattern is the opposite for lichen species associated with early-successional tree species. Some lichen traits can also drive species responses to the open environment after clearcutting; characteristics that seem to increase the probability of lichens to occur on trees retained at clearcutting are a foliose or fruticose growth form, thallus sunscreen, or asexual reproduction. The responses of saproxylic beetles to landscape stump extraction varies, with predators more negatively affected than lower trophic levels. In an attempt to elucidate different aspects of the distribution of responses, I suggest ways to develop the concept of response diversity. The diverging responses of species to forest management entails different requirements for their conservation.

AB - In forests there are many organisms that depend on trees. When forests are managed the environment for tree-associated species changes, and a lot of their habitat is lost. In boreal forests it is common with clearcutting, where almost all trees are harvested. In addition, with an increased demand for biofuel, the extraction of tree tops, branches and stumps is expanding. At the same time, some trees are retained in the open conditions after clearcutting for conservation purposes. In the boreal forests of Sweden, tree species richness is poor but the richness of flora and fauna of species associated with trees is high. I have analyzed the responses of epiphytic lichens to the environmental change on retained trees when the surrounding forest is clearcut. I have also analyzed the responses of saproxylic beetles to stump extraction in the landscape. Overall, there is a wide variety of species responses, and they can be difficult to predict. Sometimes tree traits, such as successional strategy, can help predict the responses of tree-associated species to environmental change. Sometimes the traits of the tree-associated species themselves can drive their response to environmental change. For lichens, species associated with the late-successional Norway spruce occur less on trees retained at clearcuts than on trees in closed-canopy forest. The pattern is the opposite for lichen species associated with early-successional tree species. Some lichen traits can also drive species responses to the open environment after clearcutting; characteristics that seem to increase the probability of lichens to occur on trees retained at clearcutting are a foliose or fruticose growth form, thallus sunscreen, or asexual reproduction. The responses of saproxylic beetles to landscape stump extraction varies, with predators more negatively affected than lower trophic levels. In an attempt to elucidate different aspects of the distribution of responses, I suggest ways to develop the concept of response diversity. The diverging responses of species to forest management entails different requirements for their conservation.

KW - Bayesian hierarchical models

KW - biodiversity

KW - community ecology

KW - epiphytic lichens

KW - forest ecology

KW - response diversity

KW - saproxylic beetles

KW - species models

KW - stump harvest

KW - tree retention

KW - Bayesian hierarchical models

KW - biodiversity

KW - community ecology

KW - epiphytic lichens

KW - forest ecology

KW - response diversity

KW - saproxylic beetles

KW - species models

KW - stump harvest

KW - tree retention

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SN - 978-91-7760-010-7

T3 - Acta Universitatis Agriculturae Sueciae

PB - Swedish University of Agricultural Sciences

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