Leon Bennun

• Doctor of Philosophy
• Chief Scientist at The Biodiversity Consultancy

The use of life cycle assessment (LCA) methods is rapidly expanding as a means of estimating the biodiversity impacts of organisations across complex value chains. However, these methods have limitations and substantial uncertainties, which are rarely communicated in the results of LCAs. Drawing upon the ecological and LCA literature on uncertainty...

The use of Life cycle assessment (LCA) methods is rapidly expanding as a means of estimating the biodiversity impacts of organisations across complex value chains. However, these methods have limitations and substantial uncertainties, which are rarely communicated in the results of LCAs. Drawing upon the ecological and LCA literature on uncertainty...

Nations have committed to reductions in the global rate of species extinctions through the Sustainable Development Goals 14 and 15, for ocean and terrestrial species, respectively. Biodiversity loss is worsening despite rapid growth in the number and extent of protected areas, both at sea and on land. Resolving this requires targeting the locations...

The 2022 Kunming-Montreal Global Biodiversity Framework calls upon the private sector to take substantial action to mitigate its negative impacts on biodiversity and contribute towards nature recovery. The term ‘Nature Positive’ has gained traction in biodiversity conservation discourse to describe both a societal goal and the ambitions of individu...

There is an increasing expectation on the private sector to address biodiversity impacts and contribute towards global conservation goals. Appropriate evidence use can help businesses avoid biodiversity losses and realise gains, reduce ineffective or suboptimal action, whilst minimising biodiversity‐related risks and securing opportunities from eng...

Bird and bat turbine collision fatalities are a principal biodiversity impact at wind energy facilities. Raptors are a group at particular risk and often the focus of post-construction fatality monitoring programs. To estimate fatalities from detected carcasses requires correction for biases, including for carcasses that are removed or decompose be...

There are growing calls for businesses to implement ‘nature-positive’ strategies. Convergence around a precise definition is now needed. We review definitions of ‘nature-positive’, highlight differences between ‘nature-positive’ and previous iterations of organizational biodiversity strategies (e.g. net positive impact) and propose four key element...

There are growing calls for businesses to implement ‘nature-positive’ strategies. Convergence around a precise definition is now needed. We review definitions of ‘nature-positive’ and propose four key elements for ‘nature-positive’ strategies: 1) demonstrating positive biodiversity outcomes across the entire value chain; 2) measurable outcomes agai...

There is an increasing expectation on the private sector to address biodiversity impacts and contribute towards global conservation goals. Appropriate evidence use can help businesses avoid biodiversity losses and realise gains, reduce resources wasted on ineffective or suboptimal action, whilst minimising biodiversity-related risks and securing op...

The Convention on Biological Diversity’s post-2020 Global Biodiversity Framework will probably include a goal to stabilize and restore the status of species. Its delivery would be facilitated by making the actions required to halt and reverse species loss spatially explicit. Here, we develop a species threat abatement and restoration (STAR) metric...

The mitigation hierarchy (MH) is a prominent tool to help businesses achieve no net loss or net gain outcomes for biodiversity. Technological innovations offer benefits for business biodiversity management, yet the range and continued evolution of technologies creates a complex landscape that can be difficult to navigate. Using literature review, o...

Achieving a climate-resilient future requires rapid, sustained and far-reaching transformations in energy, land-use, infrastructure and industrial systems. Large-scale expansion of renewable energy can play a critical role in meeting the world’s growing energy demands and in the fight against climate change. However, even ‘clean’ energy sources can...

Many nations use ecological compensation policies to address negative impacts of development projects and achieve No Net Loss (NNL) of biodiversity and ecosystem services. Yet, failures are widely reported. We use spatial simulation models to quantify potential net impacts of alternative compensation policies on biodiversity (indicated by native ve...

Increasing exploitation of marine natural resources and expansion of energy infrastructure, shipping, and aquaculture across the oceans are placing increased pressure on marine life. Biodiversity offsets, as the last stage of the mitigation hierarchy, provide an opportunity to promote a more sustainable basis for development by addressing residual...

A global goal of no net loss of natural ecosystems or better has recently been proposed, but such a goal would require equitable translation to country-level contributions. Given the wide variation in ecosystem depletion, these could vary from net gain (for countries where restoration is needed), to managed net loss (in rare circumstances where nat...

de Castro, J.J., Capstick, P.B., Nokoe, S., Kiara, H., Rinkanya, F., Slade, R., Okello, O. and Bennun, L., 1991. Towards the selection of cattle for tick resistance in Africa. Exp. Appl. Acarol., 12: 219-227. Half-body tick collections and visual assessment of tick burdens were performed monthly over six months on 100 bulls at the Kenya National Bo...

Loss of habitats or ecosystems arising from development projects (e.g., infrastructure, resource extraction, urban expansion) are frequently addressed through biodiversity offsetting. As currently implemented, offsetting typically requires an outcome of “no net loss” of biodiversity, but only relative to a baseline trajectory of biodiversity declin...

Over US$60 trillion is predicted to be spent on new infrastructure globally by 2040. Is it possible to meet UN Sustainable Development Goal (SDG) 9 (develop infrastructure networks) without sacrificing goals 14 and 15 (ending biodiversity loss)? We explore the potential role of “no net loss” (NNL) policies in reconciling these SDGs. We assess count...

Systematic conservation planning and Key Biodiversity Areas (KBAs) are the two most widely used approaches for identifying important sites for biodiversity. However, there is limited advice for conservation policy makers and practitioners on when and how they should be combined. Here we provide such guidance, using insights from the recently develo...

Important Bird and Biodiversity Areas (IBAs) are sites identified as being globally important for the conservation of bird populations on the basis of an internationally agreed set of criteria. We present the first review of the development and spread of the IBA concept since it was launched by BirdLife International (then ICBP) in 1979 and examine...

Critical Habitat has become an increasingly important concept used by the finance sector and businesses to identify areas of high biodiversity value. The International Finance Corporation (IFC) defines Critical Habitat in their highly influential Performance Standard 6 (PS6), requiring projects in Critical Habitat to achieve a net gain of biodivers...

Further datasets considered and justification for exclusion. Includes information on which element of the PS6 Critical Habitat they align with, the dataset investigated and the reason it was excluded from the global screening layer. (DOCX)

Relevance of regional-scale designations to Critical Habitat criteria. (DOCX)

Global screening layer (1x1 km raster) for terrestrial Critical Habitat. A GIS dataset of the terrestrial Critical Habitat screening layer is available on request for research and conservation purposes from information@unep-wcmc.org. (DOCX)

Biodiversity features included in the screening layer for the identification of Critical Habitat. Includes information on which element of the PS6 Critical Habitat they align with, the dataset used, their classification as likely or potential Critical Habitat and justification based on the degree of alignment with the PS6 definition and the certain...

Proposed alignment between the KBA criteria in the new global standard for the identification of KBAs (IUCN 2016) and IFC Critical Habitat (CH) criteria. (DOCX)

A workshop held at the University of Cambridge in May 2017 brought developers, researchers, knowledge brokers, and users together to discuss user-centred design of decision support tools. Decision support tools are designed to take users through logical decision steps towards an evidence-informed final decision. Although they may exist in different...

The IUCN Red List of Threatened Species provides assessments of extinction risk for over 80,000 species. It has become an important tool for conservation and for informing natural resource policy and management more broadly. Over the last 10–15 years, the role of the Red List in business decision-making has become increasingly significant. We descr...

Increasingly, development projects are managing biodiversity and ecosystem service risk through the application of IFC's Performance Standard 6. Central to PS6 is the identification of Critical Habitat, which in turn requires the definition of one or more Discrete Management Units. Guidance for this is limited, and DMU delineation can be especially...

Engaging constructively with stakeholders is vital to managing Biodiversity and Ecosystem Services (BES) risks successfully. Understanding and engaging with stakeholders is relevant at both corporate and operational levels and is necessary throughout the project life cycle. We have identified a wide range of potential stakeholders who have BES inte...

The Australian and Queensland governments have established the Reef Trust to strategically deliver funding to address high priority threats to the Great Barrier Reef (GBR). A component of Reef Trust funds will be derived from the pooling of offsets funds to compensate for residual significant impacts on the Great Barrier Reef. This report investiga...

World governments have committed to increase the global protected areas coverage by 2020, but the effectiveness of this commitment for protecting biodiversity depends on where new protected areas are located. Threshold-based and complementarity-based approaches have been independently used to identify important sites for biodiversity. Here we bring...

As November's IUCN World Park Congress approaches, and the IUCN develops a policy on biodiversity offsets, we sense increasing excitement about the potential for biodiversity offsets as an innovative financing mechanism for protected areas.This article is protected by copyright. All rights reserved.

In their letter, Sheil et al. appear to have misinterpreted several key points. Far from ignoring local opportunity costs, we assumed that for reasons of fairness and effectiveness, establishing new protected areas "will require the full opportunity costs of conservation to be paid" (Supplementary

World governments have committed to halting human-induced extinctions and safeguarding important sites for biodiversity by 2020, but the financial costs of meeting these targets are largely unknown. We estimate the cost of reducing the extinction risk of all globally threatened bird species (by ≥1 International Union for Conservation of Nature Red...

There is an increased appreciation of the need for horizon scanning: the identification and assessment of issues that could be serious in the future but have currently attracted little attention. However, a process is lacking to identify appropriate responses by policy makers and practitioners. We thus suggest a process and trial its applicability....

Protected areas (PAs) are a cornerstone of conservation efforts and now cover nearly 13% of the world's land surface, with the world's governments committed to expand this to 17%. However, as biodiversity continues to decline, the effectiveness of PAs in reducing the extinction risk of species remains largely untested. We analyzed PA coverage and t...

Coverage of IBAs and AZEs by PAs and by internationally designated sites, and site-scale conservation under climate change. (DOC)

Red List Index of species survival for species triggering IBAs of which over 50% are completely protected, compared with those for which≤50% are completely protected. Shading indicates the 95% confidence intervals based on uncertainty around the estimated value that is introduced by Data Deficient species. (TIF)

Observed annual percentage declines in Red List Index (RLI) are significantly different from those expected by chance based on 10,000 randomisations for (A) bird species (during 1988–2008) with>50% of IBAs completely protected (N = 1,004, P<0.001), and (B) for bird (1988–2008), mammal (1996–2008) and amphibian species (1980–2004) restricted to sing...

Completely protected IBAs (n = 737) are significantly less threatened than partially/unprotected IBAs (n = 1,263; chi-squared test: χ2 = 19.0, df = 3, P <0.001), but almost half (47%) face ‘high’ or ‘very high’ threats. (TIF)

Annual percentage decline in Red List Index for bird species (during 1988–2008) with different proportions of IBAs completely protected. Numbers within each bar refer to the number of species. Error bars show 95% confidence intervals based on uncertainty around the estimated value that is introduced by Data Deficient species. (TIF)

List of countries excluded from the analysis of PA coverage of IBAs owing to incomplete data on IBAs and/or their PA coverage. (DOCX)

Trends in mean % area protected for IBAs in different (A) habitats and (B) regions. Shading shows 95% confidence intervals based on uncertainty around date of protection (and, for a small subset of IBAs, proportion protected). (TIF)

PA coverage (% area) for IBAs in different ecosystems, habitats, regions, and relevant to different Multilateral Environmental Agreements. (DOCX)

Costs of IBA management. (DOCX)

Our aim in conducting annual horizon scans is to identify issues that, although currently receiving little attention, may be of increasing importance to the conservation of biological diversity in the future. The 15 issues presented here were identified by a diverse team of 22 experts in horizon scanning, and conservation science and its applicatio...

The target adopted by world leaders of significantly reducing the rate of biodiversity loss by 2010 was not met but this stimulated a new suite of biodiversity targets for 2020 adopted by the Parties to the Convention on Biological Diversity (CBD) in October 2010. Indicators will be essential for monitoring progress towards these targets and the CB...

This review describes outcomes of a 2010 horizon-scanning exercise building upon the first exercise conducted in 2009. The aim of both horizon scans was to identify emerging issues that could have substantial impacts on the conservation of biological diversity, and to do so sufficiently early to encourage policy-relevant, practical research on thos...

We completely agree with Wu and Petriello that a connection exists between the biodiversity crisis and threats to indigenous communities. Indeed, there are remarkable parallels between the geographic pattern of threats to biodiversity and threats to indigenous languages ([ 1 ][1]). Although this

Many migratory bird populations are in decline, with 14% of 2274 migratory species listed on the IUCN Red List as globally threatened or near-threatened with extinction, 42 of these being in the Africa-Eurasia flyway. There are many challenges in implementing effective conservation for species that cross national boundaries on migratory journeys th...

SummaryThe Taita Apalis Apalis fuscigularis (IUCN category: Critically Endangered) is a species endemic to south-eastern Kenya. We assessed population size and habitat use in the three forest sites in which it is known to occur (Ngangao, Chawia and Vuria, totalling 257 ha). The estimate of total population size, derived from distance sampling at 41...

Assessing Biodiversity Declines Understanding human impact on biodiversity depends on sound quantitative projection. Pereira et al. (p. 1496 , published online 26 October) review quantitative scenarios that have been developed for four main areas of concern: species extinctions, species abundances and community structure, habitat loss and degradati...

The continued growth of human populations and of per capita consumption have resulted in unsustainable exploitation of Earth’s biological diversity, exacerbated by climate change, ocean acidification, and other anthropogenic environmental impacts. We argue that effective conservation of biodiversity is essential for human survival and the maintenan...

Important Bird Areas (IBAs) form a network of priority sites that are critical for the conservation of birds and biodiversity. A standard framework for monitoring IBAs is being implemented by the BirdLife Partnership globally. Scores are assigned on a simple ranked scale for state (condition), pressure (threats) and response (conservation action) a...

White-breasted Cormorant (Phalacrocorax carbo) breeding timing and reproductive success were documented in 1995 and 1996 at Lake Naivasha, Kenya (0°49'S), considered to be seasonally constant. In both years, pairs breeding earlier fledged significantly more chicks per breeding attempt than pairs breeding later. Smaller brood sizes later in the seas...

The Alliance for Zero Extinction (AZE), a partnership comprising 67 of the world's biodiversity conservation non-governmental organizations, has pinpointed where Endangered and Critically Endangered species exist at one remaining known location [1xPinpointing and preventing imminent extinctions. Ricketts, T.H. et al. Proc. Natl. Acad. Sci. U. S. A....

Coordinated waterbird counts have been carried out in major Kenyan wetlands annually over the last decade. The lakes of Naivasha, Elmenteita, Nakuru (counted since 1991) and Bogoria are close to each other in the southern Rift Valley and hold the bulk of both resident and migrant waterbirds counted each year. Levels of the four lakes fluctuate subs...

Robust and rapid ways of assessing and monitoring forest biodiversity are increasingly necessary. To this end, we present a classification of forest birds in Kenya and Uganda into three simple categories: forest-specialists (FF species), forest generalists (F species) and forest visitors (f species). FF and F species, but not f species, are depende...

Habitat attrition may affect ranging patterns of individuals in natural populations, e.g. by engendering larger territory sizes as the preferred habitat decreases. Radio-telemetry was used to explore the ranging behaviour of the white-starred robin Pogonocichla stellata in the highly fragmented Taita Hills landscape, south-east Kenya. Thirty-one ma...

Our study focused on the Taita White-eye Zosterops silvanus, one of three bird species endemic to the Taita Hill forests, south-east Kenya. Formerly considered Critically Endangered, Taita White-eye has been down-listed to Endangered following the findings of this study. Between November 1998 and September 1999 we counted this species along line tr...

Sound knowledge of underlying mechanisms is essential for understanding how species respond to habitat fragmentation. Because most threatened species are typically the first ones to suffer local extinctions with forest fragmentation, studying why they fare poorly at the broader landscape scale is difficult. Related, sympatric but common species may...

Governments are often accused of responding only to short-term and parochial considerations. It is therefore remarkable that representatives of 190 countries recently committed themselves at the Convention on Biological Diversity to reducing biodiversity loss. This presents conservation biologists with perhaps their greatest challenge of the decade...

In 2005 and 2006, highly pathogenic avian influenza H5N1 infected wild birds or poultry in at least 55 countries in Asia, Europe, and Africa. Scientists still have limited understanding of how these wild birds were infected and of how the virus behaves in a field setting. Better ecological and ornithological data are essential to resolve these unce...

We studied the presence of 'floaters', i.e. non-territorial individuals roaming occupied territories awaiting future breeding opportunities, in two separate White-starred Robin (Pogonocichla stellata) populations at the Taita Hills, Kenya, using a removal experiment. Previous vegetation analyses at this site had showed that 'population Ngangao' occ...

The need for effective global monitoring of biodiversity is clearer than ever, but our measurements remain patchy and inadequate. In the biodiversity-rich tropics, a central problem is the sustainability of monitoring schemes. Locally-based, participatory approaches show promise in overcoming this problem, but may not contribute effectively to moni...

We studied the spatial and temporal variation in fruit abundance and frugivorous bird densities in a large-sized (135ha), a medium-sized (95ha) and five small-sized (each 2-8ha) forest fragments in the Taita Hills, Kenya. The large and medium patches were respectively divided into six and three plots, while the small patches were each treated as a...

The World Conservation Union (IUCN) Red List is widely recognized as the most authoritative and objective system for classifying species by their risk of extinction. Red List Indices (RLIs) illustrate the relative rate at which a particular set of species change in overall threat status (i.e. projected relative extinction-risk), based on population...

The rapid destruction of the planet's biodiversity has prompted the nations of the world to set a target of achieving a significant reduction in the rate of loss of biodiversity by 2010. However, we do not yet have an adequate way of monitoring progress towards achieving this target. Here we present a method for producing indices based on the IUCN...

The rapid destruction of the planet's biodiversity has prompted the nations of the world to set a target of achieving a significant reduction in the rate of loss of biodiversity by 2010. However, we do not yet have an adequate way of monitoring progress towards achieving this target. Here we present a method for producing indices based on the IUCN...

Site conservation is among the most effective means to reduce global biodiversity loss. Therefore, it is critical to identify those sites where unique biodiversity must be conserved immediately. To this end, the concept of key biodiversity areas (KBAs) has been developed, seeking to identify and, ultimately, ensure that networks of globally importa...

Index Values: Values for T, P, and I for Each Period and for Each Index (66 KB DOC).

Calculating Error Bars: Simulated P-Values (Proportional Change in the Index Score T) Used to Determine Error Bars for 2004 RLI Value Lists the simulated p-values (proportional change in the index score T) based on the assumption that an additional six genuine changes occurred from 2000 to 2004 but have not yet been identified owing to time lags in...

Variation in gonadal size of shot black-faced sandgrouse, Pterocles decoratus, and chestnut-bellied sandgrouse, P. exustus, considered to be indicative of their breeding condition, was studied to examine whether or not breeding seasons fall within the set shooting seasons for different parts of Kenya, and to reveal a possible relationship between r...

1 Royama, T. (1992) Analytical Population Dynamics, Chapman & Hall2 Johst, K. and Wissel, C. (1997) Extinction risk in a temporallycorrelated environment. Theor. Popul. Biol. 52, 91–1003 McCarthy, M. and Lindenmayer, D.B. (2000) Spatially correlatedextinction in a metapopulation model of Leadbeater’s Possum. Biodiv.Conserv. 9, 47–634 Engen, S. et a...

Between January 1993 and January 1995, the number of Great Cormorants (Phalacrocorax carbo) using Lake Naivasha, Kenya (00 45 S, 36 20 E) for foraging and resting increased 56%, while the number of sympatric Long-tailed Cormorants (Phalacrocorax africanus) decreased 64%. In 1995 and 1996, we documented habitat changes and conducted monthly populati...

The Kinangop highland grasslands, the world stronghold of the endangered Sharpe's longclaw (Macronyx sharpei), consist almost entirely of privately owned land. As human population in the grasslands increases, the mean acreage of land holdings decreases and more grassland is being converted to other uses. Land subdivision information, existing human...

Reproductive success and the intensity of five separate seasonal sexual characters, expressed similarly in both sexes and likely to be dependent on age and/or individual condition, were documented at a colony of great cormorants at Lake Naivasha, Kenya (00°46′ S, 36°22′ E) in 1996. The characters assessed were head filoplumes, thigh patch feathers,...

The earth's biodiversity currently faces an extinction crisis that is unprecedented. Conservationists attempt to intervene in the extinction process either locally by protecting or restoring important species and habitats, or at national and international levels by influencing key policies and promoting debate. Reliable information is the foundatio...

Montane grassland is a severely threatened habitat in Kenya. Despite a high level of faunal endemism, it has received very little conservation attention. We investigated habitat selection in a threatened grassland endemic bird species, Sharpe's longclaw (Macronyx sharpei) (family Motacillidae), in order to understand its likely response to land-use...

Fruit-eating birds play an important role in the seed dispersal of many tropical plants (e.g. Herrera 1984), and the foraging behaviour of avian frugivores may affect their seed-dispersal capabilities (Loiselle & Blake 1999,Schupp 1993, Traveset 1994). For instance,shorter visits tend to produce less clumped seed distributions (Graham et al. 1995)....