Forest Resilience, Biodiversity, and Climate Change

More documents

Recommendations

Info

Forest Resilience, Biodiversity, and Climate ChangeTable 3. Default biomass carbon values for major forest biomes, exclusive of soilcarbon.Source: Adapted from Keith et al. (in press, 2009) and compiled from IPCC (2006, 2003).Climate regionAboveground livingbiomass carbon (tCha -1 ) biome defaultvaluesRoot+dead biomasscarbon (tC ha -1 )biome defaultvaluesTotal living+deadbiomass carbon (tCha -1 ) biome defaultvaluesTropical wet 146 67 213TropicalTropical moist 112 30 142Tropical dry 73 32 105SubtropicalTemperateTropicalmontaneWarmtemperate moistWarmtemperate dryWarmtemperatemontaneCool temperatemoistCool temperatedryCool temperatemontane71 60 112108 63 17175 65 14069 63 132155 78 23359 62 12161 63 124Boreal moist 24 75 99BorealBoreal dry 8 52 60Boreal montane 21 55 7629
Forest Resilience, Biodiversity, and Climate Change5. Case-studies of forest resilience andcomparisons under climate change byforest biomeForests are all variously driven by disturbances,whether the disturbance is in the form of minorblowdown events at a scale of 150 years (IPCC 2007) largely as a result of fossilfuel burning (IPCC 2007). In addition to reducinganthropogenic CO 2 emissions, land managers areassessing the potential to increase forest carbonsequestration and storage as a mitigation strategy.In theory, improvements in ecosystem managementshould allow forests to sequester more CO 2 asthe forest growth rate improves, and thus help tomitigate anthropogenic CO 2 emissions.Biological processes accelerate as air temperatureincreases. Increases in tree respiration andmetabolism can shorten leaf retention time astemperature increases. Litter decomposition, soilnitrogen mineralization, and soil nitrification alsoincrease with increasing temperature (Mellio et al.1982), so climate change could significantly affectall of the biological functions of forests. Increasedair temperature is projected to increase fire risk andreturn interval (Dale et al. 2001). Episodic droughtwill favour more drought tolerant species over morewater demanding ones (Dale et al. 2001). Even if aforest remains intact (albeit with possible changesin the mix of dominant species), many functionalaspects of the forest and its goods and services arelikely to change. As the spatial scale increases, thepotential for climate change alterations in ecosystemstructure and function increases. Therefore, changesin water use and yield, and carbon storage in somesites, stands or even watersheds may be highlyresilient to climate change, while bio/ecoregionallythese processes will almost assuredly be less resilient.Below we consider a set of case-studies that examinethe resilience of a sample of the world’s forests. Wehave selected the case-studies by major forest biomeand assess resilience to current climate and thenormal disturbances in the system, and follow thisfor each by assessing the changes that are predictedto occur as a result of climate change. These studies,in one way or another, reflect the amount of changeand the capacity of the ecosystem biodiversity tomaintain the system in the face of predicted effectsof climate change.5.1 Boreal forest biomeThe circumpolar boreal biome occurs across NorthAmerica, Europe and Asia and has 33% of the Earth’sforested area. Boreal forests are characterized bya small number of common tree species, any ofwhich may dominate over a vast area (Mooney et al.1996). Annual temperature ranges from -5 to 5 o Cwith annual precipitation ranging from 300-1500mm. The mean maximum of the warmest monthis 10 o C. Forests in the boreal biome are relativelyyoung, assembling after the quaternary ice ages, andso may be +4-5 o C) and ‘stable’(+2-3 o C), Fischlin et al. (2009) and Sitch et al.(2003), reported predicted broad gains northwardfor boreal forest distribution, although withconversion of boreal forests to temperate forestsand grasslands at southern and central areas ofCanada and Russia. Soja et al. (2007) summarized30
Page 1 and 2: Secretariat of theConvention onBiol
Page 3 and 4: Forest Resilience, Biodiversity, an
Page 29: Forest Resilience, Biodiversity, an

Forest Resilience, Biodiversity, and Climate Change

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?