Presentation on theme: "How will rapid climate change affect species and ecological communities? Species phenology and growth Phenotypic expression of species Species’ population."— Presentation transcript:
How will rapid climate change affect species and ecological communities? Species phenology and growth Phenotypic expression of species Species’ population dynamics Gene frequencies in populations (evolution) Species distributions Species interactions Disturbance processes and community dynamics Ecosystem structure and dynamics
Biomes: global patterns of plant response to climate Biomes are general ecosystem types that occur under a particular climate regime, and exhibits characteristic vegetation structure, community organization, and ecosystem processes. Cold needle-leaved woodland (lodgepole pine) and cold shrub steppe (Great Basin sagebrush), Yellowstone National Park, 24 years after fire
Climate and Habitat Habitat is “the resources and conditions present in an area that produce occupancy” (Hall et al. 1997. Wildlife Soc. Bull. 25: 173-182) Climate space – radiation, wind, temperature, humidity Microclimate
Energy balance of an organism M + Q a = R + C + E + G + X MMetabolic energy Q a absorbed radiation Remitted radiation Cenergy exchanged by convection E latent heat energy G energy exchanged by conduction X net energy loss or gain
Some considerations in bioclimatology of animal species Endotherms vs. ectotherms –99.9% of species are ectotherms that rely primarily on external sources for body heat Behavior –Diurnal vs. nocturnal –Fossorial, semi-fossorial vs. non-fossorial –Hibernation, torpor Nutritional status Age and stage of development
Climate space (“Fundamental niche”) modeling Organism –Body mass –Voluntary min and max T –Selected body T –Latent heat transfer rate –Resting metabolic rate –Degree days for egg development Environment –Solar radiation –Wind profile –Air Temperature profile –Relative humidity –Soil temperature profile
Scales of environmental temperature variation Global Regional –Land/water –Elevation Local –Slope angle and aspect Microsite –Vegetation canopy, soil moisture, etc. Bay checkerspot butterfly
Murphy and Weiss (1992) Chapter 26 in Global Warming and biological diversity, ed. R. L. Peters and T. E. Lovejoy. Castleton, New York: Hamilton Printing.
Climate change and plant species Temperature Soil water balance Carbon dioxide Dispersal and adaptation Wollemia nobilis
CO 2 response curve of photosynthesis Diffusion limitation affected by stomata Biochemical limitation affected by light/enzymes Plants equalize physical and biochemical limitations
Inherent tradeoff between CO 2 gain and H 2 O loss
Influence of different parameters on the efficiency of the carbon dioxide uptake (ordinate) of a C 3 plant (Atriplex patula, yellow line) and a C 4 plant (Atriplex rosea, green line). Measured parameters (from left to right): light intensity, leaf temperature and concentration of carbon dioxide within the intercellular space (according to O. BJÖRKMAN and J. BERRY, 1973).
Water use efficiency C3 plants 1-3 g CO 2 intake / kg H2 0 loss 20-35°C optimal temperature C4 Plants 10-40 g/kg 30-45 C CAM Plants 20-40+ g/kg 20-35 C
GPP, NPP, and NEP Photosynthesis usually measured in units of moles carbon/leaf area/time (usually reported as net photosynthesis) Gross Primary Production (GPP) is a measure of photosynthetic activity –carbon uptake per ground area per time –Around 50% of GPP is used in respiration Net primary production (NPP) = GPP – Respiration –Net carbon (or biomass) per ground area per time Net ecosystem production (NEP) measures change in total organic matter per area per time –NEP = GPP – Respiration of Autotrophs and Heterotrophs
Components of NPP% of NPP New plant biomass40-70 Leaves and reproductive parts (fine litterfall)10-30 Apical stem growth0-10 Secondary stem growth0-30 New roots30-40 Root secretions20-40 Root exudates10-30 Root transfers to mycorrhizae10-30 Losses to herbivores, mortality, and fire1-40 Volatile emissions0-5 Components of NPP What do we usually measure?? Litterfall Sometimes stem growth Source http://www.faculty.uaf.edu/fffsc/PPTChap6.ppt.http://www.faculty.uaf.edu/fffsc/PPTChap6.ppt
Possible responses of plants to increased atmospheric CO 2 Decreased stomatal conductance Decreased transpiration Increased water use efficiency Increased photosynthetic rate Decreased nitrogen concentration Increased phenolic concentration Long term Acclimation
Predicting plant species responses to rapid climate change Plants can –Tolerate –Adapt –Disperse Issues –Local phenotypic and genotypic variation? –Rate of adaptation vs. rate of climate change? –Dispersal rates in fragmented landscapes? –Photoperiod vs. climate controls on phenology
Predicting future plant species distributions Lessons from the past Approaches –Bioclimatic modeling (realized niche models) –Physiological models (fundamental niche models) –Spatial population and community models –Dynamic [global or regional] vegetation models Dispersal through fragmented habitats
Neotoma sp. (packrat) Packrat midden, Grand Canyon, 13000 yrs. BP
Measured rates of spread for tree genera during postglacial period Oak7 km/generation Spruce 0.3-1(8) km/generation Hemlock0.5-3 km/generation Dispersal in fragmented habitats?
Summary points Microclimate is the climate experienced by organisms Species occupy distinctive habitats that reflect their physiology, interactions with other species, and dispersal. Species respond individualistically to climate variation Species persistence under a changing climate can occur through tolerance, adaptation or dispersal
A few summary points (2) Oceans and humid forests account for roughly 2/3 of the earth’s net primary production. Gross and net primary production increase in warmer and wetter climates Plants interact with the atsmophere to modify local, regional and even global climate. Increased CO2 increases water use efficiency of plants, especially C3 plants