Mixed forests to mitigate risk of insect outbreaks

Sammanfattning

The majority of agricultural and forest production systems are typically simplified systems and therefore thought to be sensitive to disturbance. Ecosystems might be less sensitive to disturbance if complexity increases. The resource concentration hypothesis predicts that complexity makes it more difficult for herbivores to find and exploit their food. The natural enemy hypothesis predicts less damage in diverse environments because enemy abundance and diversity remain higher and more stable in environments providing more alternative food sources. We explore the effect of tree diversity in two types of pine stands differing in tree diversity. We ask whether European pine sawfly (Neodiprion sertifer) larval group distribution and larval mortality, imposed by specialist natural enemies, is affected by tree diversity. We find fewer larval groups on pine trees surrounded by non-host trees, indicating that fewer egg-batches were laid. Mortality rates by specialist enemies are not affected by tree diversity but parasitism rates are likely to be higher in larger trees. Herbivores are inhibited by increased tree diversity and density, whereas natural enemies seem to be unaffected, partly increasing the resistance of more diverse forest stands against insect damage. Thus, managing for more mixed forests could mitigate risk of herbivore damage.

Nyckelord

Heterogeneity; forest management; tree diversity; herbivory; insect outbreaks; temperature; outbreak; parasitism

Publicerad i

Scandinavian Journal of Forest Research
2018, volym: 33, nummer: 8, sidor: 772-780
Utgivare: TAYLOR & FRANCIS AS

SLU författare

• Klapwijk, Maartje

  • Institutionen för ekologi, Sveriges lantbruksuniversitet
    

• Björkman, Christer

  • Institutionen för ekologi, Sveriges lantbruksuniversitet
    

Associerade SLU-program

Framtidens skogar (tom Jan 2017)
SLU Future Forests
SLU Nätverk växtskydd

UKÄ forskningsämne

Skogsvetenskap
Ekologi

Publikationens identifierare

• DOI: https://doi.org/10.1080/02827581.2018.1502805

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/97096