Biodiversity

Biodiversity is a concept developed by E.O. Wilson in 1988, which refers to the totality of genetic variation present in life forms, from species to biomes (Wilson 1988). However, the Convention on Biological Diversity (CBD; 2007), expanded Wilson’s definition as follows: ‘Biological diversity means 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’.

Unfortunately, biodiversity has been dramatically reduced in the last 50 years due to climate and land use change (Sala et al. 2000), so that biodiversity loss is one of the biggest problems that humans face in the Anthropocene (Steffen et al. 2011, 2015). As biodiversity plays an important role in ecosystem function (Cardinale et al. 2012; Lefcheck et al. 2015; Gurr et al. 2017), stability (Tilman et al. 2006), resilience (Folke et al. 2004), as well as human well-being (Cardinale et al. 2012; Roberts et al. 2015), its conservation (and enhancement within degraded ecosystems) is crucial for sustaining the increasing human population through the provision of multiple ecosystem services (Wratten et al. 2012) while minimising ecosystem dis-services (Gillespie and Wratten 2017). Conventional monoculture-based agriculture is considered to be the leading cause of biodiversity loss (Sala et al. 2000; Steffen et al. 2015; Lichtenberg et al. 2017).

Biodiversity and its functions can be restored to some extent by multiple ecologically-based strategies (Tomich et al. 2011; Kremen and Miles 2012; Wezel et al. 2014; Gurr et al. 2017). As an example, habitat manipulation using floral resources that enhance arthropod ‘fitness’ and diversity has been successfully applied to manage several pest species around the world (Collins et al. 2002; Koohafkan et al. 2011; Wezel et al. 2014; Gurr et al. 2016; Lichtenberg et al. 2017), reducing the need for synthetic pesticides (Scarratt et al. 2008; Gurr et al. 2016).

Although an increase in biodiversity in agroecosystems can drastically increase its sustainability through the provision of key ecosystem functions and services (Altieri 1999), there are some cases where biodiversity enhancement can have detrimental or neutral effects on ecosystem functions (Tscharntke et al. 2016). For this reason, agricultural techniques that aim at increasing biodiversity in agroecosystems need appropriate research that takes into account the effect of local, cultural, economic and environmental conditions on different management strategies (Karp et al. 2018). For example, the provision of shelter, nectar, alternative food and pollen (SNAP) can increase the efficacy of biological control of pests (Gurr et al. 2017). Successful examples of increasing biodiversity, and thus promoting ecosystem functions within agroecosystems can be found in South-East Asia (Gurr et al. 2016), Oceania (Scarratt et al. 2008), Central Africa (Pickett et al. 2014), South America (Altieri and Toledo 2011) and elsewhere (Kremen and Miles 2012; Wezel et al. 2014; Lichtenberg et al. 2017, Pretty et al. 2018).

Due to recent scientific advances of biodiversity-based research on the relationship between diversity and agroecosystem functions, and the need for sustainable agricultural methods that satisfy current environmental problems, the spiral concept, proposed here, can be a crucial component in developing future sustainable agricultural systems. However, enhancing appropriate biodiversity within agroecosystems requires a series of crucial steps and the interactive web-based spiral approach developed here illustrates such a pathway.

Extracted pages from E. O. Wilson 1988 about biodiversity.

Examples of high- and low-diversity farmland

A video explaining biodiversity by E. O. Wilson

Phacelia tanacetifolia Benth. in maize fields to produce shelter, nectar, alternative food and pollen (SNAP) for natural enemies (Gurr et al. 2017).

A diversified farmland to enhance several ecosystem services.Illustration: Andrew Holder / Xerces Society.

A lettuce monoculture as an example of low-diversity farmland. Photo: Allistair Pullin.

References

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Altieri MA, Toledo VM, 2011. The agroecological revolution in Latin America: rescuing nature, ensuring food sovereignty and empowering peasants. Journal of Peasant Studies 38:587–612.

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Collins KL, Boatman ND, Wilcox A, Holland JM, Chaney K, 2002. Influence of beetle banks on cereal aphid predation in winter wheat. Agriculture, Ecosystems & Environment 93: 337-350. DOI: 10.1016/S0167-8809(01)00340-1

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Pickett JA, Woodcock CM, Midega CAO, Khan ZR, 2014. Push-pull farming systems. Current Opinion in Biotechnology 26:125–132.

Pretty J, Benton TG, Pervez Bharucha Z, Dicks L, Butler Flora C, Godfray C, Goulson D, Hartley S, Lampkin N, Morris C, Pierzynski G,

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Roberts L, Brower A, Kerr G, et al, 2015. The Nature of Wellbeing: How Nature’s ecosystem services contribute to the wellbeing of New Zealand and New Zealanders. New Zealand Department of Conservation, Wellington, New Zealand.

Sala OE, Chapin III FS, Armesto JJ, et al, 2000. Global biodiversity scenarios for the year 2100. Science 287:1770–1774.

Scarratt SL, Wratten SD, Shishehbor P, 2008. Measuring parasitoid movement from floral resources in a vineyard. Biological Control 46:107–113.

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Steffen W, Richardson K, Rockström J, et al, 2015. Planetary boundaries: Guiding human development on a changing planet. Science 347:1259855.

Tilman D, Reich PB, Knops JMH, 2006. Biodiversity and ecosystem stability in a decade-long grassland experiment. Nature 441:629–632.

Tomich TP, Brodt S, Ferris H, et al, 2011. Agroecology: A Review from a global-change perspective. Annual Review of Environment and Resources 36:193–222.

Tscharntke T, Karp DS, Chaplin-kramer R, et al, 2016. When natural habitat fails to enhance biological pest control – Five hypotheses. Biological Conservation 204 B: 449-458.

Wezel A, Casagrande M, Celette F, et al, 2014. Agroecological practices for sustainable agriculture. A review. Agronomy for Sustainable Development 34:1–20.

Wilson EO (1988) Biodiversity. National Academy Press, Washington DC, Estados Unidos.

Wratten SD, Gillespie M, Decourtye A, et al, 2012. Pollinator habitat enhancement: Benefits to other ecosystem services. Agriculture, Ecosystems and Environment 159:112–122.