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Global Change Biology, FS 2017
Anna Spescha
What are the major stumbling stones for halting biodiversity decline?
Date: 08.05.2017
Supervisor: Harald Bugmann
1. Introduction
The Convention on Biological Diversity (CBD, 1992) defines biodiversity as “the variability
among living organisms from all sources including, inter alia, terrestrial, marine and other
aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems”. The Global Biodiversity Outlook 4
(GBO 4, 2014) reported that biodiversity continues to decline and pressures on biodiversity
are still increasing.
To halt the biodiversity decline, the Aichi Biodiversity Targets have been set by the CBD
(2010). Its Strategic Goal B aims to “reduce the direct pressures on biodiversity and promote
sustainable use”, with Targets 5-10: reducing habitat loss, implementing sustainable use of
aquatic resources, sustainable agriculture, aquaculture and forestry, reducing pollution, preventing and controlling invasive alien species, and reducing pressures on vulnerable ecosystems. GBO 4 reports progress towards some targets, but some show no progress (e.g., negative impacts of fisheries) or are even getting worse than better (e.g., nutrient pollution). As
the CBD was signed in 1992, one would expect that effective policies have been implemented to date, and that they should help reaching the Aichi Biodiversity Targets.
2. Questions
What measures have been implemented to decrease biodiversity loss?
Why do policies and actions taken so far fail to halt biodiversity decline?
3. Results
An important strategy to conserve biodiversity is to create Protected Areas (PAs). They “cover nearly 13% of the world’s land surface, with the world’s governments committed to expand
this to 17%” (Butchart et al., 2012). The Alliance for Zero Extinction (AZE) identified important sites for protection. Even though the number of PAs increases, the proportion of important sites for conserving birds, mammals and amphibians decreases (Butchart et al.,
2012). Conde et al. (2016) found that the conservation opportunities in AZE are large if action is taken soon enough. Overall, the selection of PAs as well as their management are
crucial for decreasing the risk of extinction for endangered species (Red List Index, Butchart
et al., 2012).
A good example of what could be evaluated for choosing the right management strategies is
the observational study by Margalida et al. (2011), evaluating the effect of cork harvesting in
Spain on the breeding of cinereous vulture. They found that adults would flee if noise was too
high, and more nestlings died in the harvesting area. However, cork harvesting is necessary
for the preservation of cork oak and brings a massive financial benefit to the population.
Margalida et al. (2011) stated that noise reduction is the more sustainable solution than relinquishing cork harvest. This study shows the complexity and difficulties in biodiversity conservation: it is not enough to install PAs without managing them, and the management needs
to consider the costs and benefits of each strategy. A lot of data is needed (e.g. observational studies, cost/benefit calculations) to evaluate conservation measures. Lack of such data
leads to implementation of actions that may not be sufficient or even counterproductive or to
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Global Change Biology, FS 2017
Anna Spescha
no activity at all, as policy makers have no certainty about the effectiveness of possible conservation measures.
The precautionary principle has been suggested and implemented to avoid inactivity excused
by lack of scientific certainty, as noted in the preamble of the CBD: “Where there is a threat
of significant reduction or loss of biological diversity, lack of full scientific certainty should not
be used as a reason for postponing measures to avoid or minimize such a threat.” (CBD,
1992). Kanongdate et al. (2012) evaluated the implementation of the precautionary principle
on a regional scale. They evaluated four case studies in Germany and rated the success of
biodiversity conservation according to criteria they defined themselves. If no data were available, it was automatically classified as unsuccessful. Thus, two of the four studies were unsuccessful. In another site, biodiversity conservation was unsuccessful because some populations decreased by more than 5% and some protected species were lost. Only at one site
did their test come to the result that the implementation was successful. If it only depended
on the criteria that the area has not been anthropogenically altered, it would have failed as
well, as solar panels were installed on 1% of the conservation area. However, this did not
have a negative influence on species richness, and the protection of this area was even costefficient. Lacking data for species (e.g., population numbers) and for economic values (e.g.,
costs of conservation, costs of species loss) are critical for the success of biodiversity conservation strategies. The authors conclude that “unclear information about species development, budget efficiency and cost effectiveness are presumably the main reasons behind implementation failure.”
A case study on New Zealand (Wallace, 2015) investigated the direct effects of the CBD on
the distribution of six bird species threatened mostly by habitat loss or change and predation
by invasive alien mammals. Although Wallace (2015) recognizes the potential for protection
of the six bird species by the CBD, she criticizes it because of its weak directive obligations.
The precautionary principle is only applied in a light version, and taking actions could easily
be postponed by policy makers with the excuse of lack of full scientific certainty. At least all
nations that signed the convention are forced to elaborate a national biodiversity strategy and
action plans. The Aichi Targets are stricter but still so flexible that nations can avoid implementing effective measures. For example, Aichi Target 12 aims at preventing extinction and
improving the conservation status of threatened species, but even this is formulated in a way
that only species with highest decrease can be considered in policy measures. Similarly,
Target 5, which is addressing habitat loss, has two weaknesses: first, it is difficult to measure
rate of habitat loss, leading to uncertainty if it could be reduced, and secondly, the unclear
formulation “when feasible” excuses minimal action. Altogether, Wallace (2015) concludes
that the “weak directive obligations inhibit the force of the CBD”, which in turn produce a
“strong national focus regarding implementation of the CBD”.
4. Conclusion
Even though more policies were implemented, biodiversity loss has not stopped yet. Many of
them are not strong and clear enough to effectively protect biodiversity. Moreover, the outcome of many policies regarding benefits and costs is unclear. Lacking data (e.g., species
numbers, rate of habitat decrease) and the lacking evaluation of policies also linked to lacking data slow down the planning and implementation of effective policies. Also, many studies
focus on single aspects and most policies attempt to regulate particular processes as well.
These approaches do not match the complexity of biodiversity and the linked ecosystem
functions and services. Trade-offs between conservation and human use of habitats need to
be critically discussed and considered. Lastly, they also need to take into account socioeconomic factors besides the already known drivers of biodiversity loss. Therefore, policies need
to be clear and strict, and they need to integrate the complex environment that is targeted.
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Global Change Biology, FS 2017
Anna Spescha
References
Butchart S, Scharlemann J, Evans M, et al., 2012. Protecting Important Sites for Biodiversity
Contributes to Meeting Global Conservation Targets. PLoS ONE 7: e32529.
Conde D, Colchero F, Güneralp B, et al., 2016. Opportunities and costs for preventing vertebrate extinctions. Current Biology 25: 219-221.
Convention on Biological Diversity (CBD), 1992.
https://www.cbd.int/convention/articles/default.shtml?a=cbd-02, 19.04.2017
Convention on Biological Diversity (CBD), 2010. Aichi Biodiversity Targets.
https://www.cbd.int/sp/targets/
Global Biodiversity Outlook 4, 2014. Secretariat of the Convention on Biological Diversity,
Montréal, 155 pages.
Kanongdate K, Schmidt M, Krawczynski R, Wiegleb G, 2012. Has implementation of the precautionary principle failed to prevent biodiversity loss at the national level? Biodiversity Conservation 21: 3307-3322.
Margalida A, Moreno-Opo R, Arroyo B, Arredondo A, 2011. Reconciling the conservation of
endangered species with economically important anthropogenic activities: interactions between cork exploitation and the cinereous vulture in Spain. Animal Conservation 14: 167174.
Wallace P, 2015. The Reduced Effect of International Conservation Agreements: A New
Zealand Case Study. Journal of Environmental Law 27: 489-516.
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