Archive for the ‘Science’ Category

Do we need pandas?

Sunday, April 22nd, 2012

Published in 2010, Ken Thompson‘s book on the uncomfortable truth about biodiversity offers a refreshing perspective for conservation.

After a very good explanation of what is meant by the term biodiversity, Ken Thompson goes on to discuss several key concepts:

  • ecosystem services, and their “links” with biodiversity
  • wilderness versus rare species
  • cost-efficiency of conservation investments (or spending)
  • the direct experience of biodiversity by people
  • One of the fist messages that the book upholds is that biodiversity is the outcome of ecosystem-level properties (structure and processes, including those determined by geography : soils, climate, etc.) and not the other way round. In this sense, conserving biodiversity because it contributes to ecosystem service provision is not the right way to frame the issue. Rather, the loss of biodiversity is an indicator of changing ecosystem-level properties, which lead to specific losses and gains in service provision. Conservation should target ecosystems, not particular species.

    Another important message is that conservation actions must take cost-efficiency into account. In this respect, once again, the focus should be on ecosystem properties and not on targeting this or that species. Another related point is the abundance of large areas of wilderness for which conservation actions could have large impacts for little investment. This is especially true when compared with conservation carried out in densely populated areas when land is scarce and thus expensive.

    In spite of the opportunity of doing things on a grand scale in the remaining wilderness areas of the world, Ken Thompson also argues that to ensure that people care about biodiversity, they must be exposed to it. As such, biodiversity should be present, and accessible, in people’s everyday surroundings: gardens, urban parks, countryside areas, etc. Reserves are not the solution to that issue.

    There are lots of interesting anecdotes and facts in the book but the messages above appear to be the most refreshing from a nature conservation perspective…

    Key issues and solutions for designing and sizing biodiversity offsets

    Friday, October 14th, 2011

    Habitat loss through development is one of the major causes of biodiversity loss. The increasingly common legal requirement to first avoid, then reduce and, if necessary, offset impacts of plans and projects on biodiversity has however not always been appropriately enforced. The blame lies mainly in bad governance such as patchy monitoring or poorly defined liabilities. Biodiversity offsets also suffer from the lack of formal methods for designing and sizing offset requirements.

    In a paper recently published in Biological Conservation, Fabien Quétier (who is involved in this blog) and Sandra Lavorel address this gap by reviewing the different tools, methods and guidelines that have been developed in different regulatory contexts to design and size biodiversity offsets.

    They formulated a typology of approaches that variously combine the methods and guidelines reviewed and then discuss how these relate to the objectives of offset policies, the components of biodiversity and ecosystems to which they apply, and the key issues for ecological equivalence.

    One of the key messages from the paper might be that when gains are not realistic, e.g. because we do not know how to enhance or restore a habitat or ecosystem function (i.e. they are non renewable), then protection of as-yet unprotected habitats or ecosystems is the only realistic offset option.

    This has several consequences, the most notable being that, in effect, using protection as offset means we assign a ratio of acceptable loss to the remaining unprotected habitat or ecosystem. For example, protecting 3 hectares for every unprotected hectare lost actually means that we accept to loose a quarter of the unprotected area. This then means we must think strategically about what we want to do with that quarter… which is then a non renewable resource too!

    Overestimating biodiversity loss?

    Thursday, June 2nd, 2011

    Earlier this May, Fangliang He and Stephen Hubbell made headline news by publishing, in Nature, a study that demonstrates that usual estimates of species extinction rates are actually overestimates. Their argument is basically as follows:

    Estimates of biodiversity loss from habitat loss are generally based on a relationship between the number of species in an area and that area’s surface. This relationship is known as the species-area curve. It is based on surveys that count species inside a survey area. The bigger the area, the more species there are. Of course, it makes sense to say that the bigger the area lost, the more species are lost.

    What He and Hubbell explain is that in establishing the species – area curves, species are added to the count as they are encountered. The survey area necessary for a first encounter with a species is necessarily smaller than the area that encompasses 100% of that species (except in the trivial case of there being only one single individual of the species).

    This larger area, which harbours 100% of the species, is the one which should be used for calculating species extinction from habitat loss. As a result, the species – area relationship gives less species going extinct for a given area of habitat loss… Makes sense doesn’t it?

    The authors insist that their point does not mean that biodiversity is not being lost at an alarming rate. That also makes sense of course.

    The ideals of ecosystem service research

    Thursday, March 3rd, 2011

    Ralf Seppelt and his co-authors from the Helmholtz Centre for Environmental Research in Leipzig (Germany) recently published an interesting inquiry into how ecosystem service research is actually conducted (pdf available here). They draw conclusions on how it should be done.

    They focused on ecosystem service studies at the regional scale, looking at 153 publications. Most studies focused on single ecosystem services (usually provisioning), using proxy-data (such as land-use or land-cover maps). Interestingly, the authors conclude that less than one third of the studies they reviewed provided a sound basis for their conclusions…

    From their review, R. Seppelt and his co-authors suggest four key components for high quality ecosystem service research:

  • Establishing the biophysical basis for ecosystem service delivery
  • Analysing trade-offs between multiple ecosystem services, in a context of environmental change and ecosystem management decisions
  • Analysing off-site effects of ecosystem management decisions on ecosystem services
  • Involving stakeholders in identifying ecosystem services, ground-truthing conclusions and management options
  • They list key criteria on which to assess whether a particular ecosystem service study actually follows their suggested guidelines. Table 1 below is taken from their paper.

    Table 1 from Seppelt et al. (2011) in Journal of Applied Ecology

    The authors mention biophysical realism as a necessary criteria for ecosystem services studies to provide a sound basis for decision making. It could be argued that the same could apply to “socio-political” or “socio-economic” realism. Stakeholder involvement does not necessarily guarantee such realism, especially when stakeholders have very heterogeneous needs and preferences and/or where there are important power asymmetries between stakeholders.

    Conservation biology for all… for free!

    Tuesday, February 22nd, 2011

    Navjot S. Sodhi of Singapore and Paul R. Ehrlich of California edited a text book on conservation biology : “Conservation Biology for All“. They published it in a free and open access format in an effort to make conservation knowledge available to as many people as possible.

    You can access the pdf version of the book (or specific chapters) through Mongabay’s website. Enjoy the read!

    Vulnerability, resilience and sustainability

    Sunday, January 2nd, 2011

    In an interesting review paper published in Global Environmental Change, Billie L. Turner outlines the separate trajectories of vulnerability and resilience research and argues that both could “join forces” and contribute to the wider goals of sustainability science. One of his main claims is that this can be done if both fields of enquiry explicitly address trade-offs in ecosystem services.

    According to Billie Turner, vulnerability has mainly focused on the effects of abrupt, external changes, on human societies and communities. In doing so, it has generated a strong literature on human adaptation and adaptive capacity (one of the three pillars of vulnerability with exposure and sensitivity). Multiple ecosystem services, and their inherent trade-offs, are however rarely addressed.

    On the contrary, while they also investigate the capacity of socio-ecological systems to self-organize and to learn and adapt, most studies of resilience have focused more strongly on the response of ecosystem-level properties to external shocks. In doing so, trade-offs between multiple ecosystem processes and functions are investigated but rarely linked to human well-fare (security, health, material well-being, social relations etc.).

    Billie Turner tells us that because decision making actually compares alternatives in terms of human well-fare (in a broad sense), the multiple pathways between it and ecosystem properties – which operate at multiple spatial scales and with multiple underlying values – must be investigated. Trade-off analysis enables us to track such pathways.

    Within sustainability science and assisted by researchers working at the interface of research-application and open to multiple explanatory perspectives, efforts have begun that point to improved integration of vulnerability and resilience research.

    He concludes that both vulnerability and resilience research would usefully contribute to furthering our understanding of trade-offs between multiple ecosystem services in a manner conductive to decision-making and sustainability.

    Ecosystem services and the Global Land Project

    Tuesday, December 14th, 2010

    The Global Land Project (GLP) is one of the main fora for ecosystem service science.

    GLP’s 2010 Open Science Conference was held in Arizona in October and several of the presentations by key-note speakers have been put on-line and several of them are particularly interesting.

  • Bob Scholes: Thinking of linking – Biodiversity, Ecosystem Services and Human Wellbeing
  • Sandra Díaz: Incorporating functional diversity and social heterogeneity in the assessment of ecosystem services
  • Steve Polasky: Ecosystem Services: Provision, Value & Policy
  • Charles Perrings: The paper from the Apache Room (on the scope and limites of monetary valuation)
  • Restoration fundamentals

    Thursday, October 28th, 2010

    The following is a modified version of discussions on the ECOLOG-L discussion list (with contributions by Wayne Tyson and Eric Branton). It summarizes the fundamentals of a successful restoration programme.

    Design and implement the required restoration actions
    Step 1: Assess current ecosystem condition (structure and processes)
    Step 2: Describe and agree on desired future/restored ecosystem condition.
    Step 3: Define and agree on actions needed to reach desired condition (taking into account feasibility, reliability and costs of the proposed actions).
    Step 4: Take bold but safe-to-fail actions (i.e. taking a “what-if” approach).

    Put adaptive management in place
    Step 5: Monitor and evaluate results from desired ecosystem condition perspective.
    Step 6: Modify actions and/or expectations in light of results.
    Step 7: Continue with revised actions and monitoring.

    Note that conditions to be evaluated should include processes (population fluctuations, properly functioning soil microbial communities, forest succession) as well as the components (species present, habitat types and proportions). This prevents a project site from being considered “restored” the second the last native grass has been planted.

    Defining desired ecosystem condition may be the most challenging step: Do we want a pristine, zero human disturbance condition? E.g., a mature mixed conifer-deciduous woodland cycled with infrequent wildfires and no management of invasive species. Do we want a slightly human-controlled condition? E.g., a mature mixed conifer-deciduous woodland preserved through fire prevention and some management of invasives. Do we want a slightly more human-managed condition? E.g., oak savannahs maintained by periodic controlled burns, conifer removals and intensive invasive species removals.

    13 important isssues for developing practical conservation goals

    Monday, March 1st, 2010

    In a review published in 2008 in Ecology Letters, David Lindenmayer and a long list of co-authors discuss some of the most important concepts used in describing, understanding and managing biodiversity and ecological processes at the landscape scale. These include classifying landscapes into habitats, describing and assessing their internal structure and condition, describing their disposition in space and time as well as their connections and hedge-effects.

    Their review of these concepts is relatively broad but difficult to follow. It does not offer a very satisfying conclusion, except a worthwhile attempt to synthesize how these concepts relate to each other in a box-and-arrow diagram.

    The more interesting part of their review is their suggestion of 13 important issues to be considered in developing practical goals for conservation. These are the following:

  • Develop long-term shared visions and quantifiable objectives
  • Manage the entire mosaic, not just the pieces
  • Consider both the amount and configuration of habitat and particular land cover types
  • Identify disproportionately important species, processes and landscape elements
  • Integrate aquatic and terrestrial environments
  • Use landscape classification and conceptual models appropriate to objectives
  • Maintain the capability of landscapes to recover from disturbances
  • Manage for change
  • Time lags between events and consequences are inevitable
  • Manage in a experimental framework
  • Manage both species and ecosystems
  • Manage at multiple scales
  • Allow for contingency
  • Each one of these issues is discussed in the paper and although they might seem trivial to some, lack of time or expertise often means they are not appropriately accounted for in the design of conservation policies. This situation makes the paper a useful reminder! The authors conclude by listing some key research topics including the challenge of making the enormous mass of ecological knowledge relevant to on-the-ground management of ecosystems and biodiversity. That’s a hard one!

    What about glacial melt in the Andes?

    Monday, February 15th, 2010

    Following the debate on the IPCC’s mistake on the future of Himalayan glaciers, and their statement (see previous post), the Inter-American Institute for Global Change Research (IAI) has asked its scientists to offer their perspective on glacial melt in the Andes. The report is available here (pdf).

    In summary, most glaciers are shrinking and although some may survive and others disappear (particularly in tropical and subtropical regions) the key message is that people who depend on rivers fed by glaciers and snow must already learn to adapt to changes in seasonal water flows.