Is terrestrial biodiversity doomed by climate change?

1. Is terrestrial biodiversity doomed by climate change? Professor Brendan Mackey, PhD Fenner School of Environment & Society Email: brendan.mackey@anu.edu.au

2. Rapid climate change is bad for people as we have made the fundamental and false assumption that climate is stable. Impacts of rising sea level and threats to food security are sufficiently serious to justify strenuous national and global mitigation efforts in order to stabilize atmospheric greenhouse gases at a concentration likely to restrict global warming to the 1-2 degree guardrail.

3. But, what of impacts of climate change on biological diversity? IPCC AR4 Synthesis: EcosystemsApproximately 20 to 30% of plant and animal species assessed so far are likely to be at increased risk of extinction if increases in global average temperature exceed 1.5 to 2.5°C (medium confidence).The resilience of many ecosystems is likely to be exceeded this century by an unprecedented combination of climate change, associated disturbances (e.g. flooding, drought, wildfire, insects,ocean acidification) and other global change drivers (e.g. landuse change, pollution, fragmentation of natural systems, overexploitation of resources).Over the course of this century, net carbon uptake by terrestrial ecosystems is likely to peak before mid-century and then weaken or even reverse, thus amplifying climate change.For increases in global average temperature exceeding 1.5 to 2.5°C and in concomitant atmospheric CO2 concentrations, there are projected to be major changes in ecosystem structure and function, species’ ecological interactions and shifts in species’ geographical ranges, with predominantly negative consequences for biodiversity and ecosystem goods and services, e.g. water and food supply.

4. The IPCC review accurately reflects the literature, but the literature is limited and ‘popular’ interpretation ‘cherry picks’, so we are not necessarily getting the full story… If species and ecosystems are doomed then why worry about and invest funds in biodiversity conservation? And why would we bother promoting ecosystem-based approaches to climate change mitigation, adaptation and the provision of ecosystem services? Species perform ecosystem functions and influence both ‘top-down’ (predator-prey release on herbivores) and ‘bottom-up’ (seeders versus sprouters) regulatory processes, and variation in composition can allow for multiple stable (dynamic equilibrium) states. If we are facing mass species extinctions then we face ecosystem collapse. Interestingly, many of the IPPC documented responses of species to climate change are erroneously interpreted as evidence of negative impacts rather than (1) evidence of rapid climate change and (2) indicative of positive natural adaptation responses

5. There are a number of factors to consider in formulating biodiversity climate change adaptation strategies and responses

6. 1. Not everything changes, all the time

7. Species can be climate change resilient when they have only one population and zero genetic diversity; e.g. Wollemi pine… Source: http://www.wollemipine.com/wallpaper.php

8. 2. Our understanding of terrestrial biodiversity & ecology is unavoidable biased by a North American perspective

9. Wetland floodplains YODFLs Steven Hopper, Kew Gardens • Young • Often disturbed • Fertile • Landscapes Postglacial lands Volcanic lands Steep slopes Coastal lands

10. OCBIL theory • Old • Climatically-buffered • Infertile • Landscapes

11. OCBILs have old micro endemic species... e.g. Southwest Australian Floristic Region: The Order DASYPOGONALES long believed to be related to grasstrees Kingia Dasypogon Calectasia Baxteria Kingia Dasypogon Calectasia

12. 3. Not all change is bad: there are winners are loser

13. A warmer world is globally a wetter world, and climate change models vary in direct and magnitude of change in wetness Figure 2.10: Large-scale relative changes in annual runoff for the period 2090–2099, relative to 1980–1999. White areas are where less than 66% of the ensemble of 12 models agree on the sign of change, and hatched areas are where more than 90% of models agree on the sign of change (Milly et al., 2005). [Based on SYR Figure 3.5 and WGII Figure 3.4]

14. Photosynthesising land plants like >C02 (~80-100ppm = no trees) and water McCarthy et al. (2010) New Physiologist 185

15. Species life history attributes vary (its handy to be tough and have big legs) Atelopus cruciger, a riparian species Rhinella marina, the cane toad Ines Van Bocxlaer et al. (2010) Gradual Adaptation Toward a Range-Expansion Phenotype Initiated the Global Radiation of Toads. SCIENCE VOL 327 5.

16. Many species have high actual or potential dispersive capacity

17. 4. Climate change is really the norm

18. Glacial highs: High CO2 High Temperature Wet Glacial troughs: Low CO2 Low Temperature Dry Humans arrive in Australia Even rapid climate change is not unknown in the paleo-record Source: National Ice Core Laboratory

19. Evolution of adaptive traits Phenotypic plasticity Retreat to refugia Dispersal to favourable locations How did species persist through past climate change? The vegetation cover was continuous and the ecosystem characteristics of land would simply change as the result of climatic impacts on biological, and ecological processes (especially NEE). Forest would expand, grasslands would morph into woodlands etc.

20. Previous climate change catalyzed speciation events Mid-Miocene ~15-20 mya cooling & drying coincided with major radiation of mammals Pliocene ~2-5 mya cooling & drying coincided with major radiation of Song bird genera & species Spotted diamond bird

21. 5. The rare gets most of the attention Leadbeater’s Possum Source: Museum Victoria Common Brushtail Possum Source: Australian Museum

22. …and the small stuff gets ignored “Soils are home to microbial communities whose aggregate membership (5 x 1030) … outnumbers the stars shining in the sky (7 x 1021). Soil complex habitats contain an estimated 104 to 106 species in a single gram …” Martin and Martin (2010) New Phytologist 185 Fig. 1 Rarefied accumulation curves of (a) species and (b) lineages of ectomycorrhizal fungi (EcMF) in four temperate and four tropical sites. Dotted lines indicate 95% CI. Brown, Tagamõisa, Estonia; green, Mt Field, Australia; blue, Huizteco, Mexico; black, UC Sierra Foothill, CA, USA; purple, Lambir Hills, Malaysia; red, Monts de Cristal, Gabon; orange, Bukit Bangkirai, Indonesia; pink, Yasuni, Ecuador. Tedersoo & Kazuhide (2010) New Phytologist 165

23. Whereas the common and the small stuff are important… ‘The vast majority of species are rare. Their global populations comprise rather few individuals, and are typically, albeit not invariably, also highly restricted in their geographic distribution’ (Gaston 2008) Most of the biosphere is made up of (1) a small number of ‘large’ common species and a (2) large number and diversity of ‘small stuff’ <1cm (invertebrates, fungi, bacteria) Most of the ‘productive work’ done in ecosystems is by common species that dominate what we see and cryptic small stuff So, how will climate change impact on these ‘foundation’ species?

24. 6. But, many species did become extinct from past climate change

25. If environmental change exceeded a species physiological niche thresholds Tolerance limits & optimal range But, beware simplistic climatic envelope models; see: Kearney et al. (2009) The potential for behavioural thermoregulation to buffer “cold-blooded” animals against climate warming. PNAS 106, 3835-284 Fig. 2.Australia-wide calculations of the percent of total daylight hours that small terrestrial ectotherms are predicted to spend below 30 °C body temperature in the sun (A,D) and above 40 °C body temperature in the shade (B, E) under current climate and with an air temperature increase of 3.0 °C.

26. If a species ecological niche changed beyond its capacity to adapt Ecosystem responses resulted in required food, shelter and nesting habitat resources no longer available New or enhanced competition, disease or predation

27. So, given all this, what should guide our biodiversity climate change adaption strategies and responses?

28. 1. Vegetation-based habitat resources are the key to animal species persistence Habitat templet theory (Southwood) Ecological theory points to the importance of habitat quality and condition as well as habitat ‘area’ & ‘quantity’ Source/sink habitat theory (Pulliam) Metabolic theory of ecology (Brown et al.)

29. fPAR: how much solar radiation plants intercept for photosynthesis • GPP: the rate at which new plant biomass is produced Where e and c are treated as constants and Rsis solar radiation at top of canopy (estimated from models). The RUE approach to modelling plant photosynthesis: • NDVI: what the satellite sensor records

30. GPP  biomass-C correlated with important habitat vegetation structural elements (e.g. hollow bearing trees) Estimated total ecosystem carbon carrying capacity of eucalypt forests in south-eastern Australia. Up-scaling based on GPP modelled from MODIS NDVI times series . (Keith, Mackey and Berry GCB 2010)

31. GPP respiration NPP biomass partitioning foliavores carnivores roots stem, branches foliage insectivores reproductive parts exudates detritivores litter nectivore frugivore soil organics granivores Plant primary productivity is the basis of the food web

32. And, temporal variability and reliability of the ‘fruits of productivity’ are critical component of habitat Southwood’s (productivity) ‘habitat template’ … a selective force on the evolution of animal life history strategies and thus their biogeography

33. Remotely sensed data enables modelling and mapping of (productivity) habitat templet mean fpar Productivity domains cv fpar minimum fpar Habitat templet for Australian continent based on GPP modelled from 250m MODIS NDVI monthly time step 2001-2006 (Mackey et al 2008)

34. Kimberly Region And, consider ‘source habitats’ in terms of ‘drought refugia’ in the ‘largely seasonally dry moderate productivity’ tropical savanna biome in Australia Source: http://www.savanna.org.au/all/images/IBRA%20savannas_fig1.jpg

35. Sandseep habitats – drought/seaonal refugia comprising small and narrow strips of vegetation at the base of sandstone ranges. These serve as microrefugial areas for small mammals, and they have generally higher species richness than the surrounding dry savannas Source: Sarah Legge, Australian Wildlife Conservancy

36. Another sandseep picture - note the thick vegetation at the base of the range, which is not associated with the river that's in the foreground Source: Sarah Legge, Australian Wildlife Conservancy

37. Another ‘drought refugia’… Source: Sarah Legge, Australian Wildlife Conservancy

38. Drought Refugia Index

39. 2. We need to be thinking about biodiversity, ecosystem resilience and adaptive capacities Multi-scale biodiversity attributes and related processes that confer resilience and adaptive capacity to terrestrial ecosystems Thompson, I., Mackey, B., McNulty, S., Mosseler, A. (2009). Forest Resilience, Biodiversity, and Climate Change. A synthesis of the biodiversity/resilience/stability relationship in forest ecosystems. Secretariat of the Convention on Biological Diversity, Montreal. Technical Series no. 43, 67 pages.

41. 3. But, the ‘habitat templet’ is where people live and do work, so biodiversity is most threatened by direct and indirect impacts of human activities Introduced species Altered water & fire regimes Habitat loss, fragmentation & degradation Source: http://www.environment.nsw.gov.au/pestsweeds/FeralCats.htm

42. “2010 Interior Department’s annual State of the Birds report shows that nearly a third of the nation’s 800 bird species are endangered, threatened or suffering from population decline.For the first time, the report adds climate change to other factors threatening bird populations, including destruction of habitat, hunting, pesticides, invasive species and loss of wetlands. The report said that oceanic and shore birds are among the most vulnerable to climate change because of rapidly changing marine ecosystems and rising sea levels (http://www.nytimes.com/2010/03/13/science/earth/13birds.html?hpw)” So, any climate change impacts are on top of existing threats which for most species will remain the priority for some decades to come as noted in recent State of the Birds report:

43. In conclusion: • Protect and restore the ‘habitat templet’ (i.e. native vegetation ecosystem cover) on a landscape-wide basis otherwise biodiversity is doomed • Keep on eye on the common species and think about the small stuff • Protect the rare stuff – as it might become the common of tomorrow (insurance) • Research relationships between biodiversity at all levels/scales and ecosystem dynamics (productivity, resilience, adaptation) • Remote sensing of the ‘habitat templet’ critical (5-D vegetation mapping; height & layers, horizontal structure, productivity, condition, time); NDVI monthly time series @30-100m please!