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1Volume 110 | Number 5/6
May/June 2014
South African Journal of Science
News & Views Understanding soil health in South Africa
Page 1 of 4
The unknown underworld:
Understanding soil health in South Africa
The need to provide food security to a growing human population in the face of global threats such as climate
change, land transformation, invasive species and pollution1 is placing increasing pressure on South African soils.
South Africa is losing an estimated 300–400 million tonnes of soil annually2, while soil degradation is a major threat
to agricultural sustainability3. In spite of these problems, treatment of soil health in biodiversity assessment and
planning in South Africa has been rudimentary to date.4,5
Defining soil health
Soil is a crucial component of the pedosphere, which sustains life, and should therefore be regarded as one of the
most important assets held by South Africans. However, in South Africa, soil is a highly neglected research focus
in ecosystem service delivery. Studies of ecosystem services often focus on more elegant and tractable systems,
such as pollination networks.6 Currently in South Africa, soils are viewed in certain sectors as resources that can
be used to generate short-term gains, rather than assets to be protected and developed. Soils form the basis for
food security through agriculture, where processes taking place in the pedosphere result in water retention, nutrient
augmentation and soil biodiversity proliferation.
In an effort to facilitate research on soil health, or at least stimulate debate on the topic, we propose that soil
health be measured by a combination of abiotic (A) and biotic (B) and socio-economic (S) aspects relative to a
benchmark measure, i.e.
Soil health = ∑A. ∑B. ∑S
where A is measured by a subset of soil physicochemical indicators (with subsets determined on the basis of
variable thresholds relating to soil type and soil usage); B is determined by standard biodiversity metrics (e.g.
species richness, abundance, network or species assemblage connectedness), incorporating biodiversity in
the context of applied strategies (e.g. agricultural push–pull systems and mixed cropping) and S is determined
by socio-economic values (e.g. monetary value, equity, human well-being). In order to scale each component,
benchmark values will also have to be determined that will serve as the denominator for calculation of changing
component values over time.7,8
Here we use a similar model to that used in above ground environmental analyses (e.g. the IUCN’s system analysis
in Leverington et al.9), but we recognise that the below ground ‘closed’ medium functions at different tempos
and scales. As such, this model is simplistic, yet a degree of ignorance exists about ‘understanding’ soils,10
strengthening the notion that soils need to be elevated to mainstream research foci where interactions among
the physical, chemical and biological components of soils receive precedence and serve as a point of departure.
For soils to operate in a complex, interacting total system manner, biodiversity in different environments serving
different socio-economic requirements can potentially be temporally and spatially separated, e.g. hydroponic farms
and conservation areas or an ecological network in which all aspects are incorporated. In some cases this can
lead to an overall greater soil health set-up than if all elements were combined in one area at a specific time period
(e.g. debate on conservation versus agriculture, or conservation and agriculture11 and landscape-scale analysis
over seasons12).
The three components of soil defined here all contribute to ecosystem services and intersect to provide healthy
soils. The model for this soil health index (Figure 1), supported by intersection descriptions and more detailed
relevant examples (Figure 2), serves to emphasise that soils are extremely complex and function in multiple
roles, and as such have a pivotal role in ecological function. Based on this framework, we formulated several key
research questions (Table 1).
The need for foundational work on soil organisms
In the last decade, the diverse roles of soil communities in the ecological function of soils has gained global
recognition.13 Several large multidisciplinary projects in Europe (such as ENVASSO and EcoFINDERS) now
focus on soil organisms using holistic approaches incorporating traditional taxonomy14 and modern molecular
techniques15. However, in South Africa, like elsewhere in the world, research in the field of soil biology has been
neglected compared with research in soil chemistry or soil physics. This scenario has started to change over the
past decade or two and South Africa is no exception in this regard. Research on a broad biological basis regarding
South African soils has increased since the mid-1990s and these outcomes are published in journals such as the
European Journal of Soil Science, Soil Biology and Biochemistry, Biogeochemistry, Soil Research, Geoderma and
the South African Journal of Plant and Soil. Sadly, however, this cannot be said of pure foundational research on
soil organisms and, despite some notable pioneering experts (e.g. Lawrence16), our knowledge of South African
soil organisms is largely restricted to taxonomically well-known groups such as ants17-19 and spiders20, and even
then this knowledge is often fragmented and poorly documented. The need to integrate existing research initiatives
was unanimously expressed at a Soil Health Workshop at the XVII Congress of the Entomological Society of
Southern Africa in July 2011. This expression led to the formation of SERG (Soil Ecosystem Research Group) – a
soil biodiversity research group that provides a platform for linking and promoting research on soil organisms.
Schalk v.d.M. Louw1
John R.U. Wilson2,3
Charlene Janion3
Ruan Veldtman2,4
Sarah J. Davies3
Matthew Addison4,5
1Department of Zoology and
Entomology, University of
the Free State, Bloemfontein,
South Africa
2South African National
Biodiversity Institute,
Kirstenbosch National
Botanical Gardens, Cape Town,
South Africa
3Centre for Invasion Biology,
Department of Botany and
Zoology, Stellenbosch University,
Stellenbosch, South Africa
4Department of Conservation
Ecology and Entomology,
Stellenbosch University,
Stellenbosch, South Africa
5Hortgro Science, Stellenbosch,
South Africa
Schalk Louw
Department of Zoology and
Entomology, University of
the Free Sate, PO Box 339,
Bloemfontein 9300, South Africa
soil signature; edaphic factors;
sustainability; food security;
sustainable agriculture
Louw SvdM, Wilson JRU,
Janion C, Veldtman R, Davies
SJ, Addison M. The unknown
underworld: Understanding soil
health in South Africa. S Afr J Sci.
2014;110(5/6), Art. #a0064, 4
© 2014. The Authors.
Published under a Creative
Commons Attribution Licence.
2Volume 110 | Number 5/6
May/June 2014
South African Journal of Science
News & Views Understanding soil health in South Africa
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Conceptual model Area Definition Examples
Happy healthy soils – production landscapes
where the inputs are minimal and biodiversity
is maintained through sustained soil ecosystem
service delivery
Sustainable flower har vesting from the wild
(Figure 2)
Mixed cropping system with conservation tillage
Ecological function – natural ecosystems with
significant functional roles. Ecological processes
and physicochemical cycles are maintained; soil
condition is preserved
Unfarmed Succulent Karoo ecosystems –
dry low primary productivity regions with
low or no animal stocking (Figure 2)
Beneficial organisms – soil organisms are used
by humans for utilitarian purposes
Biological control (e.g. entomo-pathogenic
nematodes) and vermi-composting
Input production – production systems
where physical and chemical properties are
manipulated to maintain production
Mono-cultural intensive agriculture
Biotic – soil biodiversity, including organisms
of all different taxonomic and functional groups,
which together result in multi-trophic interactions
Maputo-Pondoland Centre of Endemism
AAbiotic – physical and chemical properties of soil Iron oxide rich Kalahari sandy soils
SSocio-economic – encompasses ownership and
land use and subsequent production
Hydroponics (Figure 2)
Figure 1: Proposed conceptual scheme for defining soil. We consider healthy soils as those that provide abiotic, biotic and socio-economic services.
Hydroponics Nature reserves in the Succulent Karoo Sustainable harvesting of wild flowers
Approximately 800 ha of hydroponics in RSA in 200221 Knersvlakte Nature Reserve: 24 058 ha22 South Africa’s Agulhas Plain: 30 597 ha23
Productivity via hydroponics, means there is no ‘soil’
at all.24 However, such systems have no ecosystem
functionality. A neighbouring/interlinked soil system
is required for soil processes to continue. System will
require continual inputs.
Succulent Karoo soils are likely to harbour many
endemic species,25 although they have been poorly
studied to date. There are some important functions,
e.g. reducing erosion, but very little productive value
exists, and in many cases such soils are sensitive
to disturbance.26
Several initiatives are in place to combine economic
value with biodiversity conservation. The selling
of flowers (particularly Proteaceae) from nature
reserves as ‘green’ products raises money for
environmental restoration and management, as well
as local development.
Figure 2: Case studies highlighting how ‘soils’ differ in abiotic, biotic and socio-economic aspects (based on examples from Figure 1).
healthy soils
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South African Journal of Science
One of the first priorities identified by SERG was the need to collate and
mobilise data and collections to consolidate and compare the state of
knowledge of each group.
We anticipate that research on soils will be a major initiative linking
fundamental and applied research endeavours in the times ahead,
especially in the context of climate smart management strategies.
Having said this, we do recognise that the establishment of thresholds
for biological indicators of soil health is a far greater challenge than the
establishment of thresholds for either chemical or physical indicators of
soil health, simply because biological indicators are too variable over
short periods. Future research endeavours will therefore have to breach
this complication.
We thank our respective institutions and departments for suppor t in
terms of funding and facilities. We also thank the NRF for funding. An
anonymous reviewer is gratefully acknowledged for providing many
positive and thought-provoking comments which helped improve
the manuscript.
1. Millennium Ecosystem Assessment. Ecosystems and human well-being:
Biodiversity synthesis. Washington, DC: World Resource Institute; 2005.
2. Huntley B, Siegfried R, Sunter C. South African environments into the 21st
century. Cape Town: Human and Rousseau and Tafelberg Publishers; 1989.
3. Du Preez CC, Van Huyssteen CW, Mnkeni PNS. Land use and soil organic
matter in South Africa 2: A review on the influence of arable crop production.
S Afr J Sci. 2011;107(5/6), Art. #358, 8 pages.
4. Department of Environmental Affairs. State of the environment: Land
[homepage on the Internet]. No date [cited 2013 Oct 14]. Available from:
5. Driver A, Sink KJ, Nel JN, Holness S, Van Niekerk L, Daniels F, et al. National
biodiversity assessment 2011: An assessment of South Africa’s biodiversity
and ecosystems. Synthesis report. Pretoria: South African National
Biodiversity Institute and Department of Environmental Affairs; 2012.
6. Carvalheiro LG, Veldtman R, Shenkute A, Tesfay GB, Pirk CWW, Donaldson
JS, et al. Natural and within-farmland biodiversity enhances crop
productivity. Ecol Lett. 2011;14:251–259.
7. Lobry de Bruyn LA, Abbey JA. Characterisation of farmers' soil sense and
the implications for on-farm monitoring of soil health. Aust J Exp Agric.
8. Gugino BK, Idowu OJ, Schindelbeck RR, Van Es HM, Wolfe DW, Moebius
BN, et al. Cornell soil health assessment training manual. New York: Cornell
University; 2007.
9. Leverington F, Hockings M, Lemos Costa K. Management effectiveness
evaluation in protected areas – a global study. Gatton, Australia: IUCN; 2008.
10. Jones DL, Dennis PG, Owen AG, Van Hees PAW. Organic acid behaviour in
soils – misconceptions and knowledge gaps. Plant Soil. 2003;248:31–41.
11. Balmford A, Green R, Phalan B. What conservationists need to know about
farming. Proc R Soc B. 2012;279:2714–2724.
12. Farina A. Principles and methods in landscape ecology. Towards a science of
landscape. Dordrecht: Springer; 2006.
13. Decaëns T, Jiminéz JJ, Gioia C, Measey GJ, Lavelle P. The values of soil
animals for conservation biology. Eur J Soil Biol. 2006;42:S23–S38.
14. Huber S, Prokop G, Arrouays D, Banko G, Bispo A, Jones RJA, et al., editors.
Environmental assessment of soil for monitoring: Volume I. Indicators &
criteria. EUR 23490 EN/1. Luxembourg: Office for the official publications of
the European communities; 2008.
15. Mulder C, Vonk AJ. Nematode traits and environmental constraints in 200
soil systems: Scaling within the 60–6000 µm body size range. Ecology.
16. Lawrence RF. The biology of the cr yptic fauna of forests. With special reference
to the indigenous forests of South Africa. Cape Town: Balkema; 1953.
17. Robertson HG. Afrotropical ants (Hymenoptera: Formicidae): Taxonomic
progress and estimation of species richness. J Hymenopt Res. 2000;9:71–84.
18. Robertson HG. Revision of the ant genus Streblognathus (Hymenoptera:
Formicidae: Ponerinae). Zootaxa. 2002;97:1–16.
19. Parr CL, Robertson HG, Chown SL. Apomyrminae and Aenictogitoninae: Two
new subfamilies of ant (Hymenoptera: Formicidae) for southern Africa. Afr
Entomol. 2003;11:128–129.
20. Foord SH, Dippenaar-Schoeman AS, Haddad CR. Chapter 8 – South African
spider diversity: African perspectives on the conservation of a mega-
diverse group. In: Grillo O, Venora G, editors. Changing diversity in changing
environment. Rijeka, Croatia: InTech Publishing; 2011. p. 163–182.
21. Gull C. Study of Pythium root diseases of hydroponically grown crops, with
emphasis on lettuce [MSc dissertation]. Pretoria: University of Pretoria; 2002.
Table 1: Key research questions/topics in soil ecology in South Africa
1. What are the underlying interactions and independent values of sustainable agriculture and intensive agriculture (ABS & AS), taking cognisance that
intensive agriculture might not necessarily be unsustainable?
2. What is the human carrying capacity of a functional, healthy soil, irrespective of whether it is used for crop farming or stock farming?
3. How much of soil biodiversity is resistant, or resilient or incompatible with disturbance?
4. How can natural benchmarks for soils in South Africa be determined?
5. Can the interactions within the total system, e.g. those among production systems, soil organisms and water-based soil nutrient cycling, be analysed? Such
analysis could include the following:
Interaction and feedback loops between soil organisms and nutrient cycling.
Interaction and feedback loops between plants and soil organisms that affect nutrient cycling.
Interaction and feedback loops between soil nutrient cycling processes and crop yield.
Identification of soil organisms and their nutrient processing qualities.
Quantification of nutrient cycles.
Identification of species assemblages most beneficial to soil processes and crop yield.
News & Views Understanding soil health in South Africa
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South African Journal of Science
22. Desmet PG. A systematic plan for a protected area system in the Knersvlakte
region of Namaqualand. Stellenbosch: World Wildlife Fund; 1999. Available
23. Conradie B. Farmers’ views of landscape initiatives: The case of the
Agulhas plain, CFR. Cape Town: Centre for Social Science Research, UCT;
2010. Available from:
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Wiltshire: The Crowood Press; 2003.
25. Cincotta RP, Wisnewski J, Engelman R. Human population in the biodiversity
hotspots. Nature. 2000;404:990–992.
26. Brooks TM, Mittermeier RA, Mittermeier CG, Da Fonseca GAB, Rylands AB, Konstant
WR, et al. Habitat loss and extinction in the hotspots of biodiversity. Conserv Biol.
News & Views Understanding soil health in South Africa
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... But the necessity of providing food security to a growing human population in the face of climate change, land transformation, biological invasions and pollution (MEA, 2005) is placing increasing pressure on South African soils. Research is urgently needed to understand how abiotic, biotic, and socioeconomic factors interact to affect soil health in southern Africa, with the lack of integrated knowledge on soil biodiversity in the region posing a major current limitation to such understanding (Louw et al., 2014). ...
... With around a quarter of the world's biodiversity hotspots, more Africa-based taxonomists are needed. In South Africa, the need to integrate existing information and work collectively led to the formation of the Soil Ecosystem Research Group (SERG) with the aim to provide a platform for linking and promoting research on soil organisms (Louw et al., 2014). One of the first priorities identified was the need to collate and mobilise data and collections such that the state of knowledge of each group can be consolidated and compared. ...
... In particular, intensified land-use is a threat to soil biodiversity globally (Tsiafouli et al., 2015), and in South Africa (Scholtz and Chown, 1993). The livelihoods of people in South Africa depend in many ways on the continued functioning of the soil ecosystem, so there is an urgent need for basic biodiversity knowledge in order to facilitate the soil ecosystem research required to assess sustainability (Louw et al., 2014). There are clearly some commonalities in how soil biota have been sampled. ...
... However, global change drivers and their synergistic effects (Millennium Ecosystem Assessment 2005) might cause extinctions of species not even known to science (Essl et al. 2013;Costello et al. 2013). One aspect that has often been overlooked is the significant contribution of soil fauna to soil health, below ground diversity, and more broadly to ecosystem functioning (Wardle 2002, Wardle et al. 2004, Louw et al. 2014. ...
... The need to enlarge South Africa's capacity to answer applied and basic research questions on the roles and impacts of earthworms in the functioning of natural ecosystems was unanimously agreed upon during a workshop on soil organisms at the XVII Congress of the Entomological Society of Southern Africa (July 2011), and separately by the CAPE Invasive Alien Animal Working Group (May 2011) (Louw et al. 2014). ...
... To build our ecological and taxonomic knowledge of soil fauna in South Africa, studies of soil organisms need more coordination (Louw et al. 2014). In order to do this, one needs to move away from traditional ad hoc sampling to more coordinated, standardised sampling for comparison with other studies. ...
Full-text available
Earthworms are an important component of southern African invertebrate diversity, due both to their influential roles in soil ecosystems, and the relatively large number of species. As of 2010, there were 282 indigenous earthworm species (most endemic) known to South Africa belonging to three families: Microchaetidae, Tritogeniidae and Acanthodrilidae. In addition, 44 introduced species from six families had been recorded. However, earthworms are rarely included in environmental monitoring or conservation programmes—partly because sampling and species identification are difficult and many sampling methods are destructive and/or toxic. In this paper we review the earthworm sampling techniques most commonly used by screening data from a digitised literature collection on South African earthworms and on-line global searches. By examining a case study sampling of three vegetation types, this paper highlights taxonomic challenges and the effort required to properly curate specimens. The study provides recommendations for future sampling and highlights some key priorities for future work on the group. From the literature review in early 2012, it is clear that collection techniques are often insufficiently recorded in published work. A total of 10 938 publications from the period 1950 to 2012 were found from the literature search and digitised collection and from these only 32 papers recorded the sampling methodology (mainly hand sorting) for South African research, pointing to the need to adopt standard sampling and reporting protocols. We also tested two of the most popular methodologies in the field. Sampling was conducted in January and February 2012 at four sites, with 24 plots at each site (12 digging and 12 using mustard extraction). A total of 2 094 earthworms collected could be assigned a species name, with introduced species predominating at both disturbed and natural sites. It took a team of three to five people digging and hand collecting all earthworm specimens encountered in a plot of 50 cm × 50 cm × 20 cm deep around 45 to 60 minutes. However, much more time was spent curating and identifying samples. While we recommend following the ISO (ISO11268-3, ISO23611-1) protocol for collecting introduced taxa, to get a complete inventory of South African earthworms a range of sampling techniques will be required; in particular, a large 1 m × 1 m × 20 cm plot is required for many large bodied native taxa, and the collection of giant earthworms will require different approaches. The identification of specimens requires skills that are scarce in the country and so there is an urgent need for training and funding for fundamental work on earthworm taxonomy. An atlasing project could serve as a focal point for future research. In providing some general recommendations based on the long and fruitful history of research on earthworms in South Africa, we are optimistic that a better understanding of the group will help us to both improve our usage of natural resources and provide insights into this vitally important edaphic group.
... This knowledge will in future become increasingly important as environmental conditions change as a result of climate and other changes. Soil is a service-providing asset under growing pressure (vdM Louw et al. 2014). It is home to an array of species of soil invertebrates which is enormous, encompassing virtually all terrestrial invertebrate phyla. ...
... This, in turn, influences the productivity of the soil, along with its resilience (i.e. the capacity of the soil to return to a normal state after a perturbation; see Mitchell et al. 2000), and its ability to provide other important ecosystem services (Woomer & Swift 1994;Robinson et al. 2012). In general, there is limited knowledge on the diversity of soil fauna and their linkage to the entire ecosystem structure and functioning (Warren & Zou 2002;Barrios 2007) and baseline information (regarding diversity, assemblage composition and their responses to environmental and anthropogenic factors) on this diverse group of organisms is lacking (Louw et al. 2014;Janion-Scheepers et al. 2016). ...
Many wetland systems are being lost or degraded by human activities such as plantation forestry. Therefore, efforts to restore these wetland systems are important for biodiversity recovery. We assess the recovery of arthropod assemblages that occupy hydromorphic grassland topsoil and leaf litter after the removal of exotic pine trees. We sampled arthropods in three biotopes (natural untransformed hydromorphic grasslands, restored hydromorphic grasslands and commercial pine plantations) replicated across a large‐scale timber‐grassland mosaic in the KwaZulu‐Natal Midlands, South Africa. In the restored sites, overall species richness, as well as species richness of spiders, ants and orthopterans was significantly higher than in plantations, and was as high as in natural, untransformed sites. Additionally, overall assemblage structure along with spider, beetle, ant, and orthopteran assemblages showed no significant differences between restored and natural grasslands. Therefore, pine tree removal enables recovery of these arthropod taxa to levels similar to those in natural hydromorphic grassland. Recovery was rapid, with the assemblages in some restored sites resembling those in untransformed sites after only six years, indicating a high level of resilience and recovery in these systems. Contrary to expectations, time since pine removal had a negative effect on arthropod recovery. This was due to the strongly negative effect of alien invasive American bramble (Rubus cuneifolius), which was most common in older restored sites, causing deviation from their restoration trajectory. The potential for arthropod recovery in these hydromorphic grasslands is high, but successful restoration is dependent on ongoing appropriate grassland management, especially removal of bramble. This article is protected by copyright. All rights reserved.
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This paper responds to calls for more normative research on biodiversity accounting and reporting. It develops a model for reporting on biodiversity informed by earlier work on biodiversity reporting, ecological reporting and extinction accounting as well as the guidance on integrated and sustainability reporting developed by the International Integrated Reporting Council (IIRC) and the Global Reporting Initiative (GRI) respectively. The resulting ‘integrated biodiversity reporting mode’ is designed to provide a more nuanced tool for reporting on biodiversity. While the model is intended to be used by multiple organisations, its application is illustrated using the South African National Parks (SANParks). A detailed content analysis of the SANParks’ annual reports over seven years (2013–2019) is used to identify different types of disclosures, categorised according to the type of environmental information being reported and the associated capitals outlined by the IIRC. Applying the model to SANParks reveals how it is possible to provide a more detailed report on biodiversity than would be the case if only existing reporting frameworks are used. The proposed reporting model is not without challenges, but it can be applied to report more effectively on biodiversity-related risks and the interconnections between biodiversity and the different resources/capitals which are required to manage it. As a result, this paper contributes to the debate on how to report on biodiversity and demonstrates how the largely theoretical work on biodiversity reporting can be applied in practice.
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This discursive paper develops a normative model for accounting for soil health inspired by earlier work on biodiversity reporting, ecological accounting and extinction accounting. The model provides a framework for reporting on the biological context, strategic relevance and policy implications of soil degradation at an organisational level. It offers suggestions on how to report on environmental performance and post-implementation reviews using the guidelines provided by the Global Reporting Initiative (GRI) and the International Integrated Reporting Council (IIRC) as a frame of reference. While the model focuses specifically with soil health, it can be readily adapted to deal with other environmental issues. It should be relevant for practitioners considering how to deal with emerging environmental issues in their sustainability or integrated reporting. At the same time, the paper answers calls for additional research on the change potential of accounting systems which bridges the gap between theory and practice.
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Purpose We are currently experiencing what is often called the sixth period of mass extinction on planet Earth, caused undoubtedly by the impact of human activities and businesses on nature. The purpose of this paper is to explore the potential for accounting and corporate accountability to contribute to extinction prevention. The paper adopts an interdisciplinary approach, weaving scientific evidence and theory into organisational disclosure and reporting in order to demonstrate linkages between extinction, business behaviour, accounting and accountability as well as to provide a basis for developing a framework for narrative disclosure on extinction prevention. Design/methodology/approach The paper is theoretical and interdisciplinary in approach, seeking to bring together scientific theories of extinction with a need for corporate and organisational accountability whilst recognising philosophical concerns in the extant environmental accounting literature about accepting any business role and capitalist mechanisms in ecological matters. The overarching framework derives from the concept of emancipatory accounting. Findings The outcome of the writing is to: present an emancipatory “extinction accounting” framework which can be embedded within integrated reports, and a diagrammatic representation, in the form of an “ark”, of accounting and accountability mechanisms which, combined, can assist, the authors argue, in preventing extinction. The authors suggest that the emancipatory framework may also be applied to engagement meetings between the responsible investor community (and non-governmental organisations (NGOs)) and organisations on biodiversity and species protection. Research limitations/implications The exploratory extinction accounting and accountability frameworks within this paper should provide a basis for further research into the emancipatory potential for organisational disclosures and mechanisms of governance and accountability to prevent species extinction. Practical implications The next steps for researchers and practitioners involve development and implementation of the extinction accounting and engagement frameworks presented in this paper within integrated reporting and responsible investor practice. Social implications As outlined in this paper, extinction of any species of flora and fauna can affect significantly the functioning of local and global ecosystems, the destruction of which can have, and is having, severe and dangerous consequences for human life. Extinction prevention is critically important to the survival of the human race. Originality/value This paper represents a comprehensive attempt to explore the emancipatory role of accounting in extinction prevention and to bring together the linkages in accounting and accountability mechanisms which, working together, can prevent species extinction.
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If farmers are to determine whether their farm goals for resource condition are being met, and whether changes in farm management are leading towards a more sustainable farming system, then they need to be able to monitor these areas. Yet to date, an easy to use, practical and reliable method to be used by farmers to monitor trends in soil health has not been developed. This has been a consequence mainly of developing soil monitoring packages in isolation from the end user, and relying on 'expert' advice to guide farmers' management of the soil rather than empowering them to be more self-reliant in this area. This study sought to collaborate with farmers in the development of a soil health checklist. The research process acknowledged the importance of local conditions, farmers' existing knowledge on soils and their preferences for delivery and presentation of the final product. The study focused on farmers located in the north-west cropping region of New South Wales, Australia. This article reports on a prototype for a farmer's soil health checklist — the features they use, how they recognise those features, especially the language they use to describe a healthy and unhealthy soil, and finally the techniques they use to determine those features.
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Traits of 29,552 individual soil nematodes were recorded in 200 (agro)ecosystems across The Netherlands. In addition to the body size (length and width) and body mass of soil nematodes, this new data set includes information on taxonomy, life stage, sex, feeding habit, trophic level, geographic location, sampling period, ecosystem type, soil type, and basic chemistry (pH in water, organic carbon, total nitrogen and phosphorus contents, and soil nutrient ratios). All the physical, chemical and biological information were accumulated and organized over different environmental categories regarding soil and land use (4 soil types and 3 land-use types resulting in 7 combinations). We envisage that our data will be of interest to researchers dealing with applied soil ecology, as well as those interested in allometry, biological stoichiometry, and soil food webs. Given the data paucity to address the relationships among habitat and nematode growth and size reported by Yeates and Boag (2003), these data can provide empirical more evidence for such investigations.
Full-text available
The decline of soil organic matter as a result of agricultural land use was identified for a review with the ultimate aim of developing a soil protection strategy and policy for South Africa. Such a policy is important because organic matter, especially the humus fraction, influences the characteristics of soil disproportionately to the quantities thereof present. Part 1 of this review dealt with the spatial variability of soil organic matter and the impact of grazing and burning under rangeland stock production. In this second part of the review, the impact of arable crop production on soil organic matter is addressed. A greater number of studies have addressed the degradation of soil organic matter that is associated with arable crop production than the restoration. However, cropping under dryland has been found to result in significant losses of soil organic matter, which is not always the case with cropping under irrigation. Restoration of soil organic matter has been very slow upon the introduction of conservational practices like zero tillage, minimal tillage, or mulch tillage. Reversion of cropland to perennial pasture has also been found to result in discouragingly slow soil organic matter restoration. Although increases or decreases in soil organic matter levels have occurred in the upper 300 mm, in most instances this took place only in the upper 50 mm. The extent of these changes was dependent inter alia on land use, soil form and environmental conditions. Loss of soil organic matter has resulted in lower nitrogen and sulphur reserves, but not necessarily lower phosphorus reserves. Depletion of soil organic matter coincided with changes in the composition of amino sugars, amino acids and lignin. It also resulted in a decline of water stable aggregates which are essential in the prevention of soil erosion. Although much is known about how arable crop production affects changes in soil organic matter, there are still uncertainties about the best management practices to maintain and even restore organic matter in degraded cropland. Coordinated long-term trials on carefully selected ecotopes across the country are therefore recommended to investigate cultivation practices suitable for this purpose.
The southern African ant genus Streblognathus has long been regarded as being monotypic but a morphological reappraisal of available specimens shows that there are two species: Streblognathus aethiopicus (F. Smith), which occurs in the southern karoo of the Eastern Cape, and Streblognathus peetersi sp. nov., which occurs in the eastern grasslands of southern Africa. Workers and males are described and keyed. Male genitalia are illustrated and the significance of the large barbs on the penis valves is discussed.
Principles and methods of landscape ecology are intensively used to model and to manage disturbed landscapes and menaced pristine areas as well. Students and professionals can find a new version of "Principles and Methods in Landscape Ecology" firstly published in 1998 by Chapman & Hall (London). Landscape ecology is an integrative and multi-disciplinary science and "Principles and Methods in Landscape Ecology" reconciles the geological, botanical, zoological and human perspectives. In particular new paradigms and theories like percolation, metapopulation, hierarchies, source-sink models, have been integrated, in this last edition, with the recent theories on bio-complexity, information and cognitive sciences. Methods for studying landscape ecology are covered including spatial geometry models and remote sensing in order to create confidence toward techniques and approaches that require a high experience and long-time dedication. Principles and Methods in Landscape Ecology is a textbook useful to present the landscape in a multi-vision perspective for undergraduate and graduate students of biology, ecology, geography, forestry, agronomy, landscape architecture and planning. Sociology, economics, history, archaeology, anthropology, ecological psychology are some sciences that can benefit of the holistic vision offered by this texbook. A relevant goal of this second edition is to increase confidence in the new generations of students and practitioners for considering the ecological systems as the result of the integration between ecosystemic (non spatial) and landscape (spatial) patterns and processes.
Nearly half the world's vascular plant species and one-third of terrestrial vertebrates are endemic to 25 “hotspots” of biodiversity, each of which has at least 1500 endemic plant species. None of these hotspots have more than one-third of their pristine habitat remaining. Historically, they covered 12% of the land's surface, but today their intact habitat covers only 1.4% of the land. As a result of this habitat loss, we expect many of the hotspot endemics to have either become extinct or—because much of the habitat loss is recent—to be threatened with extinction. We used World Conservation Union [ IUCN ] Red Lists to test this expectation. Overall, between one-half and two-thirds of all threatened plants and 57% of all threatened terrestrial vertebrates are hotspot endemics. For birds and mammals, in general, predictions of extinction in the hotspots based on habitat loss match numbers of species independently judged extinct or threatened. In two classes of hotspots the match is not as close. On oceanic islands, habitat loss underestimates extinction because introduced species have driven extinctions beyond those caused by habitat loss on these islands. In large hotspots, conversely, habitat loss overestimates extinction, suggesting scale dependence (this effect is also apparent for plants). For reptiles, amphibians, and plants, many fewer hotspot endemics are considered threatened or extinct than we would expect based on habitat loss. This mismatch is small in temperate hotspots, however, suggesting that many threatened endemic species in the poorly known tropical hotspots have yet to be included on the IUCN Red Lists. We then asked in which hotspots the consequences of further habitat loss (either absolute or given current rates of deforestation) would be most serious. Our results suggest that the Eastern Arc and Coastal Forests of Tanzania-Kenya, Philippines, and Polynesia-Micronesia can least afford to lose more habitat and that, if current deforestation rates continue, the Caribbean, Tropical Andes, Philippines, Mesoamerica, Sundaland, Indo-Burma, Madagascar, and Chocó–Darién–Western Ecuador will lose the most species in the near future. Without urgent conservation intervention, we face mass extinctions in the hotspots. Resumen: Casi la mitad del total de plantas vasculares del mundo y un tercio de los vertebrados terrestres son endémicos en 25 “áreas críticas” para la biodiversidad, cada una de las cuales tiene por lo menos 1500 especies de plantas endémicas. En ninguno de estos sitios permanece más de un tercio de su hábitat prístino. Históricamente, cubrían 12% de la superficie terrestre, pero en la actualidad su hábitat intacto cubre solo 1.4% del terreno. Como resultado de esta pérdida de hábitat esperamos que muchas de las especies endémicas a estos sitios estén extintas o – porque la pérdida de hábitat es reciente – se encuentren amenazadas de extinción. Utilizamos Listas Rojas de UICN para comprobar esta predicción. En general, entre la mitad y dos tercios de las plantas amenazadas y el 57% de los vertebrados terrestres amenazados son endémicos de áreas críticas para la biodiversidad. Para aves y mamíferos en general, las predicciones de extinción en las áreas críticas para la biodiversidad, basadas en la pérdida de hábitat, coinciden con el número de especies consideradas extintas o amenazadas independientemente. En dos clases de áreas críticas para la biodiversidad la coincidencia no es muy grande. En islas oceánicas, la pérdida de hábitat subestima la extinción porque las especies introducidas han causado más extinciones que las producidas por la reducción del hábitat. Por lo contrario, la pérdida de hábitat sobrestima la extinción en áreas críticas para la biodiversidad extensas, lo que sugiere una dependencia de escala (este efecto también es aparente para plantas). Para reptiles, anfibios y plantas mucho menos especies endémicas son consideradas amenazadas o extintas por pérdida de hábitat. Sin embargo, esta discordancia es pequeña en áreas críticas para la biodiversidad en zonas templadas templadas, lo que sugiere que muchas especies endémicas amenazadas en las poco conocidas áreas críticas para la biodiversidad en zonas tropicales aun están por incluirse en las Listas Rojas. Posteriormente nos preguntamos en que áreas críticas para la biodiversidad serían más serias las consecuencias de una mayor pérdida de hábitat (absoluta o con las tasas actuales de deforestación). Nuestros resultados sugieren que el Arco Oriental y los Bosques Costeros de Tanzania/Kenia, Filipinas, Polinesia/Micronesia no pueden soportar mayores pérdidas y que, si continúan las tasas de deforestación actuales, el Caribe, Andes Tropicales, Filipinas, Mesoamérica, Sundaland, Indo-Burma, Madagascar y Chocó/Darién/Ecuador Occidental perderán más especies en el futuro. Sin acciones urgentes de conservación, habrá extinciones masivas en las áreas críticas para la biodiversidad.