The Role of Biotic Disturbance Agents in Carbon-Climate Connections

Transcription

1 The Role of Biotic Disturbance Agents in Carbon-Climate Connections Jeffrey Hicke Department of Geography University of Idaho Emphasis: Forests, bark beetles, western North America Credit: Leslie Manning/Canadian Forest Service

2 Interactions among forests, insects, fire, carbon, climate climate atm. CO 2 insect outbreaks fire forests Photo/image credits. Climate: A. Rouvin and A.Walk (commons.wikimedia.org), CO 2 : globalwarmingart.com; Insects: J. Hicke, Fire: K. Wattenmaker, firepix.blm.gov ; Forests: J. Hicke

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4 Another scholarly work

5 Questions Are biotic disturbances important in C cycling? What are the impacts of outbreaks on C stocks and fluxes? Can we predict future outbreaks? Photo by Jeff Hicke Photo by Jeff Hicke

6 Questions Are biotic disturbances important in C cycling? What are the impacts of outbreaks on C stocks and fluxes? Can we predict future outbreaks? Photo by Jeff Hicke Photo by Jeff Hicke

7 Mountain pine beetle outbreak Central Colorado August 2007 QuickBird satellite imagery ; 2.4- m spa al resolu on ; true- color Mountain pine beetle outbreak Central Colorado August 2007 QuickBird satellite imagery ; 2.4- m spa al resolu on ; true- color

8 Cumulative mortality area, Bark beetles are significant forest disturbances Meddens et al., Ecol. App., 2012

9 Major bark beetle outbreaks, pinyon ips engraver beetles Douglas- fir beetle unspecified bark beetles western balsam bark beetle mountain pine beetle mul ple outbreaks, Meddens et al., Ecol. App., 2012

10 Carbon Impacts of MPB in Western Canada 13 million ha affected in 2007 Sink of C from atmosphere Source of C to atmosphere Cumulative impact: equivalent to 5 years of emissions from Canada s transportation sector Source: Kurz et al. 2008, Nature Slide courtesy W. Kurz, CFS

11 Insect outbreaks and Canada s net carbon fluxes total outbreaks fire harvest sink source net C flux Kurz and Apps, EA, 1999

12 Bark beetle outbreaks and C stocks 60 Carbon in killed trees in the Western US 50 Cumula ve amounts beetles: 289 Tg C fire: 285 Tg C Bark beetles Carbon (Tg/year) Forest fires Hicke et al., ERL, in press

13 Extensive forest damage in other parts of the world spruce bark beetle, Germany Siberian silkmoth, 1995 Kaultz et al., 2011 moths, Scandinavia Post et al., : 50 75% of dead and dying trees 1: 75% of dead and dying trees Kharuk et al., 2004

14 Questions Are biotic disturbances important in C cycling? What are the impacts of outbreaks on C stocks and fluxes? Can we predict future outbreaks? Photo by Jeff Hicke Photo by Jeff Hicke

15 1. Time since disturbance Simulated C dynamics following severe beetle outbreak LAI anomalies NEP CWD anomalies NPP anomalies Rh anomalies Edburg et al., JGR, 2011

16 NEP depends on timing of snagfall Simula on prescribe 5, 10, 25- year delay before snagfall ini a on ecosystem: C sink ecosystem: C source Edburg et al., JGR, 2011

17 2. Type of disturbance agent Growth reducers Tree killers William M. Ciesla, Forest Health Management Interna onal USDA Forest Service - Ogden Archive, USDA Forest Service, Bugwood.org bugwood.org

18 Effects of transient defoliation Forest tent caterpillar LAI defolia on reflush GPP 22% NEP Year a er Year before 79% Year of a ack Cook et al., Ecosystems, 2008

19 Long legacy of bark beetle outbreak Kurz et al., Nature, 2008

20 3. Host preferences and variability in mortality Preferred host species Bentz et al., BioScience, 2010

21 3. Host preferences and variability in mortality Beetles prefer older, larger hosts Safranyik and Carroll, 2006

22 3. Host preferences and variability in mortality Variability in tree mortality within an outbreak Mountain pine beetle outbreak in Colorado Meddens et al., Rem. Sens. Env., 2013

23 3. Host preferences and variability in mortality Variability in tree mortality within a region Major impacts to regional NEP by mountain pine beetle Minor impacts to regional NEP by hemlock woolly adelgid 12% change 8% change Kurz et al., Nature, 2008 Albani et al., CJFR, 2010

24 3. Host preferences and variability in mortality Postoutbreak stand characteristics affect regrowth larger postdisturbance ANPP increase smaller postdisturbance ANPP increase Aboveground produc on of woody C (Mg C/ha/yr) lots of small trees a acked run una acked run a few larger trees Pfeifer et al., Glob. Ch. Biol., 2011

25 Questions Are biotic disturbances important in C cycling? What are the impacts of outbreaks on C stocks and fluxes? Can we predict future outbreaks? Photo by Jeff Hicke Photo by Jeff Hicke

26 Bad news: Lots of different insects/pathogens Bentz et al., BioScience, 2010

27 Good news: only a few major species commonality in drivers (?) Bentz et al., BioScience, 2010

28 Complexity in drivers, interactions beetle, tree scales stand scales landscape scales Raffa et al., BioScience, 2008

29 Limited understanding of most insects/pathogens Factors influencing mountain pine beetle epidemics Factors related to trees: presence of host tree species stem density stand age drought stress on trees density dependent climate Factors related to beetles: nearby beetle source temperature effects on winter beetle mortality popula on synchroniza on/ one- year life cycles (year- round temperatures) Photo courtesy USDA Forest Service, Safranyik et al. 1975; Shore and Safranyik 1992; Carroll et al. 2004; Logan and Powell 2001

30 Expected decline of beetle outbreak Use of scenarios Expected outbreak of spruce budworm Kurz et al., Nature, 2008 Dymond et al., Ecosystems, 2010

31 More complete insect model European spruce bark beetle Pest and Diseases Image Library, Bugwood.org Jonsson et al., Ag. For. Met., 2013

32 More complete insect model simula ons observa ons Jonsson et al., Ag. For. Met., 2013

33 on bad days Conclusions on good days complex situa ons range of agents and drivers limited scien fic understanding limited observa ons varia on in C responses prognos c modeling is challenging impacts of insects, pathogens important regionally beginning to understand historical impacts enough (?) is known about a few significant species any advance is progress interes ng, challenging research