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Saturday, May 3, 2014

Terrestrial Ecosystem Loss and Biosphere Collapse


By Dr. Glen Barry
Independent Political Ecology Scientist
glen.barry@gmail.com

Excerpt of manuscript accepted for publication mid-2014 by Management of Environmental Quality

Abstract

 Planetary boundary science defines key thresholds in the Earth System's biogeochemical conditions that precede ecosystem collapse and threaten human well-being. Terrestrial ecosystems enter into the nine originally defined planetary boundaries only indirectly, through boundaries such as biodiversity and land use. This study proposes a measurable terrestrial ecosystem boundary to answer the question: what extent of landscapes, bioregions, continents, and the global Earth System must remain as connected and intact core ecological areas and agro-ecological buffers t sustain local and regional ecosystem services as well as the biosphere commons? Two preeminent considerations are connectivity of large ecosystem patches, enabling them to persist as the matrix for the landscape, and critical collapse of the dominant large habitat patch – or "percolating cluster" – into smaller, more isolated habitats, amid a matrix of human development. This transition, found to occur at about 40% habitat loss in landscapes and bioregions, is likely to be similar at continental and global scales.
A new planetary boundary threshold is proposed based on ecology’s percolation theory: that across scales 60% of terrestrial ecosystems must remain, setting the boundary at 66% as a precaution, to maintain key biogeochemical processes that sustain the biosphere and for ecosystems to remain the context for human endeavors. Strict protection is proposed for 44% of global land, 22% as agro-ecological buffers, and 33% as zones of sustainable human use.
Because humanity is now the major force shaping the biosphere, up to 50% of Earth's land surface has already been cleared of natural ecosystems; thus the biosphere may already have lost its global percolating cluster. If so, with diminished connectivity, the global ecological system is now composed of islands of nature within a sea of humanity, meaning critical water, climate, soil, and other ecosystems processes are at risk. This observation suggests that to sustain the biosphere it is urgent to protect remaining large, relatively intact terrestrial ecosystems, especially old-growth and primary forests. This will require accelerating current approaches such as biosphere reserves, and taking up new polices such as a carbon tax to fund protection and restoration of natural and agro-ecological terrestrial ecosystems. To ensure global ecological sustainability, it will be necessary to reconnect matrices of intact ecosystems across scales, so that globally the biosphere and its constituent ecological processes and patterns can percolate back to connected nature as the context to all life. Otherwise, it is hypothesized the global biosphere may collapse and the Earth System perish.


Introduction to Planetary Boundaries
From Malthus (1798), through Aldo Leopold's land ethic (1949), to The Limits to Growth (Meadows et al. 1972), the Millennium Ecosystem Assessment (2005), and finally current planetary boundary and global change science (Rockström et al. 2009a, 2009b) runs a strand of concern about human growth's impacts upon Earth's biophysical systems – terrestrial ecosystems in particular – and about requirements for global ecological sustainability, while avoiding biosphere collapse. Our biosphere is composed of Earth's thin mantle of life present at, and just above and below, the Earth's surface. Some have indicated that human impacts upon the biosphere are analogous to a large, uncontrolled experiment, which threatens its collapse (Trevors et al. 2010). Little is known regarding what collapse of the biosphere would look like, how long it would take, what are its ecosystem and spatial patterns, and whether it is reversible or survivable. But it is becoming more widely recognized that Earth's ecosystem services depend fundamentally upon holistic, well-functioning natural systems (Cornell 2009).
Accelerating human pressures on the Earth System are exceeding numerous local, regional, and global thresholds, with abrupt and possibly irreversible impacts upon the planet's life-support functions (UNEP 2012). Planetary boundaries provide a framework to study these phenomena, by defining a "safe operating space for humanity with respect to the Earth System" (Rockström et al. 2009a). Planetary boundary studies seek to set control variable values that are a safe distance from thresholds of key biophysical processes governing the planet's self-regulation to maintain conditions conducive to life (Rockström et al. 2009b). This builds upon landmark efforts by Meadows et al. (1972) to first define global limits to growth. Their prediction that key resource scarcities would emerge has proven remarkably accurate (Turner 2008), albeit delayed – but not avoided – through the advent of computer technology. Ecological and economic warnings since at least Malthus have called attention to economies' dependence upon natural resources. The observation that near-exponential growth of human population and economic activity cannot be sustained, far from being disproven, is more valid than ever (Brown et al. 2011). Those who deny limits to growth are unaware of biological realities (Vitousek 1986).
The initial planetary boundary exercise identified nine global-scale processes, including climate change, rate of biodiversity loss (terrestrial and marine), nitrogen and phosphorus cycles, ozone depletion, ocean acidification, freshwater, land use change, chemical pollution, and atmospheric aerosol loading (Figure 1). Preliminary safe planetary thresholds were established for seven of these, and three – rate of biodiversity loss, climate change, and the nitrogen cycle – were found to have already surpassed such a threshold (Rockström et al. 2009a). Many such changes occur in a nonlinear, abrupt manner; others are more incremental and subtle. Yet both types of change threaten the viability of contemporary human societies by diminishing or destroying ecological life-support systems. If one or more of these boundaries are crossed, it could be "deleterious or even catastrophic" as nonlinear, abrupt environmental change occurs at the continental to planetary scale (Rockström et al. 2009b).
Here an ecologically rich revision to the planetary boundary framework is proposed – in the tradition of political ecology, not ignoring politics – to set the threshold of how many intact terrestrial ecosystems are required to sustain the biosphere. It is not possible to carry out controlled experiments upon our one biosphere to know at what point collapse occurs. We are thus left with observational studies and synthesis papers regarding what is known about ecosystem collapse at other scales. This paper first reviews what is known about biodiversity and old-growth forest loss, abrupt climate change, and ecosystem collapse as ecological systems are diminished at lesser scales. Next, the critical phase shift seen as landscapes percolate from nature surrounding humanity, to small reserves surrounded by human works, is presented as analogous to outcomes for the biosphere, whose terrestrial ecosystems are after all simply a large-scale landscape.
The remainder of the paper synthesizes these findings regarding ecosystem loss and thresholds in loss of ecosystem connectivity into a rationale for recognition of a 10th planetary boundary in regard to terrestrial ecosystem loss. It is suggested that some two-thirds of Earth’s land surface should be protected totally (44%) or partially (another 22%) to avoid biosphere collapse. Given current best estimates are that approximately one-half of Earth’s terrestrial ecosystems have already been lost, the discussion centers around biocentric policy measures required to protect and restore terrestrial ecosystem connectivity in order to maintain global ecological sustainability.



Figure 1: Proposing a Terrestrial Ecosystem Loss Planetary Boundary. Currently nine planetary systems are recognized as providing a safe operating space for humanity, as long as boundaries are not exceeded. It is thought three systems (denoted with +) have already surpassed their boundaries. This paper proposes a Terrestrial Ecosystem boundary of 66% ecosystem land cover (44% as intact natural ecosystems and 22% as agro-ecological buffers) to avoid biosphere collapse. Best estimates are that about 50% of terrestrial ecosystems have been lost; thus this boundary has been surpassed too, albeit full impacts may not yet be realized due to time lags (adapted from Rockström et al. 2009a).

Coming Soon: the rest of this journal article as published mid-2014, including these headings:
Biodiversity and Old-Growth Forest Loss, Abrupt Climate Change, and Ecosystem Collapse
Percolation Theory and Landscape Connectivity
Terrestrial Ecosystem Loss as a Planetary Boundary
Biocentric Discussion on Achieving Global Ecological Sustainability




References
Allen, T. F. H. and Hoekstra, T. W. (1992), Toward a unified ecology: complexity in ecological systems, Columbia University Press, New York.
Andren, H. (1994), “Effects of habitat fragmentation on birds and mammals in landscapes with different proportions of suitable habitat: a review”, Oikos, 355-366.
Barnosky, A. D., Hadly, E. A., Bascompte, J., Berlow, E. L., Brown, J. H., Fortelius, M., … & Smith, A. B. (2012), “Approaching a state shift in Earth's biosphere”, Nature, 486(7401), 52-58.
Barnosky, A. D., Matzke, N., Tomiya, S., Wogan, G. O., Swartz, B., Quental, T. B., … & Ferrer, E. A. (2011), “Has the Earth's sixth mass extinction already arrived?” Nature, 471(7336), 51-57.
Barry, G. R., Rooney, T. P., Ventura, S. I., & Waller, D. M. (2001), “Evaluation of biodiversity value based on wildness: a study of the western Northwoods, Upper Great Lakes, USA”, Natural Areas Journal, 21: 229-242.
Bascompte, J., & Sole, R. V. (1996), “Habitat fragmentation and extinction thresholds in spatially explicit models”, Journal of Animal Ecology, 465-473.
Bellard, C., Bertelsmeier, C., Leadley, P., Thuiller, W., & Courchamp, F. (2012), “Impacts of climate change on the future of biodiversity”, Ecology Letters.
Biermann, F. (2012), “Planetary boundaries and earth system governance: exploring the links”, Ecological Economics, 81, 4-9.
Bhagwat, S. A., Nogué, S., & Willis, K. J. (2012), “Resilience of an ancient tropical forest landscape to 7500 years of environmental change”, Biological Conservation, 153, 108-117.
Biggs, R., Carpenter, S. R., & Brock, W. A. (2009), “Turning back from the brink: Detecting an impending regime shift in time to avert it”, Proceedings of the National academy of Sciences, 106(3), 826-831.
Bonan, G. B. (2008), “Forests and climate change: forcings, feedbacks, and the climate benefits of forests”, Science, 320(5882), 1444-1449.
Breshears, D. D., López-Hoffman, L., & Graumlich, L. J. (2011). “When ecosystem services crash: preparing for big, fast, patchy climate change”, AMBIO: A Journal of the Human Environment, 40(3), 256-263.
Brodie, J., Post, E., & Laurance, W. F. (2012), “Climate change and tropical biodiversity: a new focus”, Trends in Ecology & Evolution, 27(3), 145–150.
Brown, J. H., Burnside, W. R., Davidson, A. D., Delong, J. R., Dunn, W. C., Hamilton, M. J., … & Zuo, W. (2011), “Energetic limits to economic growth”, BioScience, 61(1), 19-26.
Brovkin, V., Raddatz, T., Reick, C. H., Claussen, M., & Gayler, V. (2009), “Global biogeophysical interactions between forest and climate”, Geophysical Research Letters, 36(7), L07405.
Brundtland, G., Ehrlich, P., Goldemberg, J., Hansen, J., Lovins, A., Likens, G., … & International Union for the Conservation of Nature (2012) “Environment and Development Challenges: The Imperative to Act”, Blue Planet Laureates.
Bryant, D., Nielsen, D., & Tangley, L. (1997), Last frontier forests: Ecosystems and economies on the edge, World Resources Institute, Washington, D.C.
Bryant, R. L. and Bailey, S. (1997), Third World Political Ecology, Psychology Press.
Butler, R. A., & Laurance, W. F. (2008), “New strategies for conserving tropical forests”, Trends in Ecology & Evolution, 23(9), 469-472.
Cairns, J. (2010), “Threats to the biosphere: eight interactive global crises”, Journal of Cosmology, 8, 1906-1915.
Carpenter, S. R., Cole, J. J., Pace, M. L., Batt, R., Brock, W. A., Cline, T., ... & Weidel, B. (2011), “Early warnings of regime shifts: a whole-ecosystem experiment”, Science, 332(6033), 1079-1082.

Chapin III, F. S., Randerson, J. T., McGuire, A. D., Foley, J. A., & Field, C. B. (2008), “Changing feedbacks in the climate-biosphere system”, Frontiers in Ecology and the Environment, 6(6), 313-320.
Choat, B., Jansen, S., Brodribb, T. J., Cochard, H., Delzon, S., Bhaskar, R., … & Zanne, A. E. (2012), “Global convergence in the vulnerability of forests to drought”, Nature, 491, (7426) , 752–755.
Cornell, S. (2012), “On the System Properties of the Planetary Boundaries”, Ecology and Society, 17(1), r2.
Cox, P. M., Betts, R. A., Collins, M., Harris, P. P., Huntingford, C., & Jones, C. D. (2004), “Amazonian forest dieback under climate-carbon cycle projections for the 21st century”, Theoretical and Applied Climatology, 78(1), 137-156.
Crutzen, P. J. (2002), “Geology of mankind”, Nature, 415(6867), 23-23.
Dale, V. H., Joyce, L. A., McNulty, S., Neilson, R. P., Ayres, M. P., Flannigan, M. D., … & Michael Wotton, B. (2001), “Climate change and forest disturbances”, BioScience, 51(9), 723-734.
Dalgaard, T., Hutchings, N. J., & Porter, J. R. (2003), “Agroecology, scaling and interdisciplinarity”, Agriculture, Ecosystems & Environment, 100(1), 39-51.
Daly, H. E. (2005), “Economics in a full world”, Scientific American, 293(3), 100-107.
Diamond, M. (1984), “Historic extinctions: A Rosetta stone for understanding prehistoric extinctions”, in Martin, P. and Klein, R. (Eds.), Quaternary Extinctions: A Prehistoric Revolution. University of Arizona Press, Tucson, AZ, 824-862.
Dobson, A., Ralls, K., Foster, M., Soulé, M. E., Simberloff, D., Doak, D., ... & Johns, D. (1999), “Corridors: Reconnecting Fragmented Landscapes”, in Soulé, M. E., and Terborgh, J. (eds.), Continental Conservation: Scientific Foundations of Regional Reserve Networks, Island Press, Washington, D.C.
Drake, J. M., & Griffen, B. D. (2010), “Early warning signals of extinction in deteriorating environments”, Nature, 467(7314), 456-459.
Ehrlich, P. and Ehrlich, A. (1981), Extinction: the causes and consequences of the disappearance of species, Random House, New York.
Ellis, E. C. (2010), “Anthropogenic transformation of the terrestrial biosphere”, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 369(1938), 1010-1035.
Ericksen, P. J., Ingram, J. S., & Liverman, D. M. (2009), “Food security and global environmental change: emerging challenges”, Environmental Science & Policy, 12(4), 373-377.
Estes, J. A., Terborgh, J., Brashares, J. S., Power, M. E., Berger, J., Bond, W. J., … & Wardle, D. A. (2011), “Trophic downgrading of planet earth”, Science, 333(6040), 301-306.
Foley, J. A., Ramankutty, N., Brauman, K. A., Cassidy, E. S., Gerber, J. S., Johnston, M., … & Zaks, D. P. (2011), “Solutions for a cultivated planet”, Nature, 478(7369), 337-342.
Foley, J. A., DeFries, R., Asner, G. P., Barford, C., Bonan, G., Carpenter, S. R., … & Snyder, P. K. (2005), “Global consequences of land use”, Science, 309(5734), 570-574.
Folke, C., Jansson, Å., Rockström, J., Olsson, P., Carpenter, S. R., Chapin, F. S., … & Westley, F. (2011), “Reconnecting to the biosphere”, AMBIO: A Journal of the Human Environment, 1-20.
Folke, C., Carpenter, S., Walker, B., Scheffer, M., Elmqvist, T., Gunderson, L., & Holling, C. S. (2004), “Regime shifts, resilience, and biodiversity in ecosystem management”, Annual Review of Ecology, Evolution, and Systematics, 557-581.
Francis, C., Lieblein, G., Gliessman, S., Breland, T. A., Creamer, N., Harwood, R., … & Poincelot, R. (2003), “Agroecology: the ecology of food systems”, Journal of Sustainable Agriculture, 22(3), 99-118.
Galaz, V., Biermann, F., Crona, B., Loorbach, D., Folke, C., Olsson, P., … & Reischl, G. (2012), “‘Planetary boundaries’—exploring the challenges for global environmental governance,” Current Opinion in Environmental Sustainability.
Gibson, L., Lee, T. M., Koh, L. P., Brook, B. W., Gardner, T. A., Barlow, J., … & Sodhi, N. S. (2011), “Primary forests are irreplaceable for sustaining tropical biodiversity”, Nature, 478(7369), 378-381.
Gustafson, E. J., & Parker, G. R. (1992), “Relationships between landcover proportion and indices of landscape spatial pattern”, Landscape Ecology, 7(2), 101-110.
Haberl, H., Erb, K. H., Krausmann, F., Gaube, V., Bondeau, A., Plutzar, C., … & Fischer-Kowalski, M. (2007), “Quantifying and mapping the human appropriation of net primary production in earth's terrestrial ecosystems”, Proceedings of the National Academy of Sciences, 104(31), 12942-12947.
Hannah, L., Midgley, G., Andelman, S., Araújo, M., Hughes, G., Martinez-Meyer, E., … & Williams, P. (2007), “Protected area needs in a changing climate”, Frontiers in Ecology and the Environment, 5(3), 131-138.
Hansen, J., Sato, M., & Ruedy, R. (2012), “Perception of climate change”, Proceedings of the National Academy of Sciences, 108, 2415-2423.
Hansen, J., & Sato, M. (2011), “Paleoclimate Implications for Human-Made Climate Change”, Proceedings of Milutin Milankovitch 130th Anniversary Symposium.
Hansen, J., Sato, M., Kharecha, P., Beerling, D., Masson-Delmotte, V., Pagani, M., … & Zachos, J. C. (2008), “Target Atmospheric CO2: Where Should Humanity Aim?” Open Atmospheric Science Journal, 2, 217.
Hastings, A., & Wysham, D. B. (2010), “Regime shifts in ecological systems can occur with no warning”, Ecology Letters, 13(4), 464-472.
Hargis, C. D., Bissonette, J. A., & David, J. L. (1998), “The behavior of landscape metrics commonly used in the study of habitat fragmentation”, Landscape Ecology, 13(3), 167-186.
Heyder, U., Schaphoff, S., Gerten, D., & Lucht, W. (2011), “Risk of severe climate change impact on the terrestrial biosphere”, Environmental Research Letters, 6(3), 034036.
International Panel on Climate Change (IPCC) (2007). Climate Change 2007: impacts, adaptation and vulnerability.
Janzen, D. H. (1986), “The eternal external threat”, in M. E. Soulé (ed.), Conservation biology. The science of scarcity and diversity. Sinauer, Northampton, Mass.
Jones, T., Bamford, A. J., Ferrol-Schulte, D., Hieronimo, P., McWilliam, N., and Rovero, F. (2012), “Vanishing wildlife corridors and options for restoration: a case study from Tanzania”, Tropical Conservation Science, Vol. 5(4):463-474.
Kareiva, P., and Marvier, M. (2003), “Conserving Biodiversity Coldspots, Recent calls to direct conservation funding to the world's biodiversity hotspots may be bad investment advice”, American Scientist, 91(4), 344-351.
Kondrat'ev, K. Y., Losev, K. S., Ananicheva, M. D., & Chesnokova, I. V. (2001), “Elementary structural units of the biosphere and landscapes”, in Doklady Biological Sciences (Vol. 380, No. 1, pp. 448-449), MAIK Nauka/Interperiodica.
Kosoy, N., Brown, P. G., Bosselmann, K., Duraiappah, A., Mackey, B., Martinez-Alier, J., … & Thomson, R. (2012), “Pillars for a flourishing Earth: planetary boundaries, economic growth delusion and green economy”, Current Opinion in Environmental Sustainability, 4(1), 74-79.
Kricher, J. (1997), A Neotropical Companion, Princeton University Press, Princeton, New Jersey.
Kuecker, G. D., & Hall, T. D. (2011), “Resilience and Community in the Age of World-System Collapse”, Nature and Culture, 6(1), 18-40.
Laurance, W. F., Useche, D. C., Rendeiro, J., Kalka, M., Bradshaw, C. J., Sloan, S. P., … & Plumptre, A. (2012), “Averting biodiversity collapse in tropical forest protected areas”, Nature, 489(7415), 290-294.
Laurance, W. F. (2004), “Forest-climate interactions in fragmented tropical landscapes”, Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 359(1443), 345-352.

Lenton, T. M., Held, H., Kriegler, E., Hall, J. W., Lucht, W., Rahmstorf, S., & Schellnhuber, H. J. (2008), “Tipping elements in the Earth's climate system”, Proceedings of the National Academy of Sciences, 105(6), 1786-1793.
Leopold, A. (1949), A Sand County Almanac, Oxford University Press: New York.
Lindenmayer, D. B., Laurance, W. F., & Franklin, J. F. (2012), “Global Decline in Large Old Trees”, Science, 338: 1305-1306.
Lovelock, J. E. (1979), Gaia: A new look at life on Earth, Oxford University Press, Oxford, UK.
Luyssaert, S., Schulze, E. D., Börner, A., Knohl, A., Hessenmöller, D., Law, B. E., … & Grace, J. (2008), “Old-growth forests as global carbon sinks”, Nature, 455(7210), 213-215.
Maclean, I. M., & Wilson, R. J. (2011), “Recent ecological responses to climate change support predictions of high extinction risk”, Proceedings of the National Academy of Sciences, 108(30), 12337-12342.
Malthus, T. R. (1798), An Essay on the Principle of Population, Prometheus, Amherst, New York.
Malcolm, J. R., Liu, C., Neilson, R. P., Hansen, L., & Hannah, L. E. E. (2006),  “Global warming and extinctions of endemic species from biodiversity hotspots”, Conservation Biology, 20(2), 538-548.
Meadows, D. M., Randeus Jorgen, D. L. III, & William, W. (1972), The Limits to Growth, Universe, New York.
Millennium Ecosystem Assessment (2005), Ecosystems and human well-being: our human planet: summary for decision-makers, Island Press, (Vol. 5).
Mooney, H., Larigauderie, A., Cesario, M., Elmquist, T., Hoegh-Guldberg, O., Lavorel, S., … & Yahara, T. (2009), “Biodiversity, climate change, and ecosystem services”, Current Opinion in Environmental Sustainability, 1(1), 46-54.
Moorcroft, P. R. (2006), “How close are we to a predictive science of the biosphere?” Trends in Ecology & Evolution, 21(7), 400-407.
Nasi, R., & Frost, P. G. (2009), “Sustainable forest management in the tropics: Is everything in order but the patient still dying”, Ecology and Society, 14(2), 40.
Nepstad, D. C., Stickler, C. M., Soares-Filho, B., & Merry, F. (2008), “Interactions among Amazon land use, forests and climate: prospects for a near-term forest tipping point”, Philosophical Transactions of the Royal Society B: Biological Sciences, 363(1498), 1737-1746.
Noss, R. F., Dobson, A. P., Baldwin, R., Beier, P., Davis, C. R., Dellasala, D. A., … & Tabor, G. (2012), “Bolder thinking for conservation”, Conservation Biology, 26(1), 1-4.
Noss, R. F., Dinerstein, E., Gilbert, B., Gilpin, M., Miller, B. J., Terborgh, J., & Trombulak, S. (1999), “Core areas: where nature reigns”, Continental conservation: scientific foundations of regional reserve networks, Island Press, Washington, DC, 99-128.

Noss, R. and Cooperrider, A. (1994), Saving nature's legacy: protecting and restoring biodiversity, Island Press, Washington, D. C.
Noss, R. (1992), “The Wildlands Project: Land conservation strategy”, Wild Earth, Special Issue (1): 10-25.

Obersteiner, M., Böttcher, H., & Yamagata, Y. (2010). Terrestrial ecosystem management for climate change mitigation. Current Opinion in Environmental Sustainability, 2(4), 271-276.
Olson, D. M., & Dinerstein, E. (2002), “The Global 200: Priority ecoregions for global conservation”, Annals of the Missouri Botanical Garden, 199-224.
O'Neill, B. C., Dalton, M., Fuchs, R., Jiang, L., Pachauri, S., & Zigova, K. (2010), “Global demographic trends and future carbon emissions”, Proceedings of the National Academy of Sciences, 107(41), 17521-17526.
Pardini, R., de Arruda Bueno, A., Gardner, T. A., Prado, P. I., & Metzger, J. P. (2010). Beyond the fragmentation threshold hypothesis: regime shifts in biodiversity across fragmented landscapes. Plos One, 5(10), e13666.
Peterson, G. (2000), “Political ecology and ecological resilience: An integration of human and ecological dynamics”, Ecological Economics, 35(3), 323-336.
Rahmstorf, S., Cazenave, A., Church, J. A., Hansen, J. E., Keeling, R. F., Parker, D. E., & Somerville, R. C. (2007), “Recent climate observations compared to projections”, Science, 316(5825), 709-709.
Riitters, K. H., & Wickham, J. D. (2012), “Decline of forest interior conditions in the conterminous United States”, Scientific Reports, 2(653), 1-4.
Rockström, J., Steffen, W., Noone, K., Persson, Å., Chapin, F. S., Lambin, E. F., … & Foley, J. A. (2009a), “A safe operating space for humanity”, Nature, 461(7263), 472-475.
Rockström, J., Steffen, W., Noone, K., Persson, Å., Chapin III, F. S., Lambin, E., … & Foley, J. (2009b), “Planetary boundaries: exploring the safe operating space for humanity”, Ecology and Society, 14(2), 32.
Rosenzweig, C., Karoly, D., Vicarelli, M., Neofotis, P., Wu, Q., Casassa, G., … & Imeson, A. (2008), “Attributing physical and biological impacts to anthropogenic climate change”, Nature, 453(7193), 353-357.
Running, S. (2012), “A Measurable Planetary Boundary for the Biosphere”, Science, 337, 1458-1459.
Sasaki, N., & Putz, F. E. (2009), “Critical need for new definitions of ‘forest’ and ‘forest degradation’ in global climate change agreements”, Conservation Letters, 2(5), 226-232.
Scheffer, M., Bascompte, J., Brock, W. A., Brovkin, V., Carpenter, S. R., Dakos, V., … & Sugihara, G. (2009), “Early-warning signals for critical transitions”, Nature, 461(7260), 53-59.
Scheffer, M., Carpenter, S., Foley, J. A., Folke, C., & Walker, B. (2001),  “Catastrophic shifts in ecosystems”, Nature, 413(6856), 591-596.
Schlesinger, W. H. (2009), “Planetary boundaries: thresholds risk prolonged degradation”, Nature Reports Climate Change, 112-113.
Schumaker, N. H. (1996), “Using landscape indices to predict habitat connectivity”,  Ecology, 1210-1225.
Sheil, D., & Murdiyarso, D. (2009), “How forests attract rain: an examination of a new hypothesis”, BioScience, 59(4), 341-347.
Soulé, M. E., & Sanjayan, M. A. (1998), “Conservation Targets: Do They Help?” Science, 279(5359), 2060-2061.
Soulé, M. (1991), “Conservation: Tactics for a constant crisis”, Science, 253: 744-750.
Soulé, M. and Terborgh, J. (1999a), “The Policy and Science of Regional Conservation”, Continental Conservation: Scientific Foundations of Regional Reserve Networks, Island Press, Washington, D. C., 1-17.
Soulé, M. E., & Terborgh, J. (1999b). Conserving nature at regional and continental scales—a scientific program for North America. BioScience, 49(10), 809-817.
Soulé, M. E. and Noss, R. (1998), “Rewilding and biodiversity as complementary tools for continental conservation”, Wild Earth, (8(3)): 18-28.
Steffen, W., Persson, Å., Deutsch, L., Zalasiewicz, J., Williams, M., Richardson, K., … & Svedin, U. (2011), “The Anthropocene: From global change to planetary stewardship”, AMBIO: A Journal of the Human Environment, 1-23.
Swift, T. L., & Hannon, S. J. (2010), “Critical thresholds associated with habitat loss: a review of the concepts, evidence, and applications”, Biological Reviews, 85(1), 35-53.
Taylor, D. M., & Taylor, G. M. (2007) “The collapse and transformation of our world”, Journal of Futures Studies, 11(3), 29-46.
Terborgh, J. and van Schaik, C. (1997), “Minimizing Species Loss: The Imperative of Protection”, Last stand: Protected areas and the defense of tropical biodiversity, Oxford University Press, New York, 15-33.
Trevors, J. T., Stavros, N., & Saier Jr, M. H. (2010), “The Big Biosphere Experiment” Water, Air, & Soil Pollution, 205, 53-54.
Turner, G. M. (2008), “A comparison of The Limits to Growth with 30 years of reality”, Global Environmental Change, 18(3), 397-411.
United Nations Environment Programme (2012), “Global Environment Outlook 5: Summary for Policy Makers”, United Nations Environment Programme.
United Nations Environment Programme (2002), Global Environment Outlook 3: Past, present and future perspectives, London: 397.
Vieira, S., Trumbore, S., Camargo, P. B., Selhorst, D., Chambers, J. Q., Higuchi, N., & Martinelli, L. A. (2005), “Slow growth rates of Amazonian trees: consequences for carbon cycling” Proceedings of the National Academy of Sciences of the United States of America, 102(51), 18502-18507.

Vitousek, P. M., Mooney, H. A., Lubchenco, J., & Melillo, J. M. (1997), “Human domination of Earth's ecosystems,” Science, 277(5325), 494-499.
Vitousek, P. M., Ehrlich, P. R., Ehrlich, A. H., & Matson, P. A. (1986), “Human appropriation of the products of photosynthesis”, BioScience, 36(6), 368-373.
Walker, P. A. (2005), “Political ecology: where is the ecology”, Progress in Human Geography, 29(1), 73-82.
Walker, B., & Steffen, W. (1997), “An overview of the implications of global change for natural and managed terrestrial ecosystems”, Conservation Ecology, 1(2).
Williams, J. C., & Snyder, S. A. (2005), “Restoring habitat corridors in fragmented landscapes using optimization and percolation models”, Environmental Modeling and Assessment, 10(3), 239-250.
Williams, M. (2003), Deforesting the Earth: From Prehistory to Global Crisis, The University of Chicago Press, Chicago, IL.
Williams, R. S. (2000), “A modern Earth Narrative: what will be the fate of the biosphere?” Technology in Society, 22(3), 303-339.
Wilson, E. O. (1985), “The biological diversity crisis”, BioScience, 35(11), 700-706.
With, K. A., & Crist, T. O. (1995), “Critical thresholds in species' responses to landscape structure”, Ecology, 76(8), 2446-2459.
Wu, J. (2004), “Effects of changing scale on landscape pattern analysis: scaling relations”, Landscape Ecology, 19(2), 125-138.
Zalasiewicz, J., Williams, M., Haywood, A., Ellis, M., Zalasiewicz, J., Williams, M., ... & Ellis, M. (2011), “The Anthropocene: a new epoch of geological time?” Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 369(1938), 835-841.
Zimmerman, B. L., & Kormos, C. F. (2012), “Prospects for sustainable logging in tropical forests”, BioScience, 62(5), 479-487.