Evidence and people's perceptions of the importance of biodiversity and integrated land use management for ecosystem services and local livelihoods

Evidence and people's perceptions of the importance of biodiversity and integrated land use management for ecosystem services and local livelihoods

Pollination by bees, and other species, has been proven extremely important for the production of many agricultural crops (see Ricketts et al. (2008) and Farwig et al. (2009) for an overview). Recent studies have mapped and modelled pollination on a regional (Petz and Van Oudenhoven 2012) and larger scale (Schulp et al. 2012), but it has to be noted that most of these models are heavily dependent on secondary data and making generalised assumptions. Pollination studies have unearthed a few trends, for instance relationships between pollination rate and fruit set as well as pollinators' distance to fields and crop yield increase (Ricketts et al. 2008). However, there is still a need for primary data on pollinators' diversity contributions, drivers of pollinators' population numbers and regional differences of crop yield increase as a result of pollination (Farwig et al. 2009). In this issue, Munyuli (2012) describes a study on the influence of drivers to pollinators' abundance and diversity on different spatial scales, ranging from microscale to regional scale. By comparing primary data from 30 different coffee farms in Uganda, Munyuli was able to deduce that distance to forest and/or wetlands and intensity of farming were negatively correlated with the potential yield of coffee fields. In addition, the effects of different pollination treatments were compared to those of natural habitats. His study calls for the establishment of coffee fields in the vicinity of natural habitats as well as establishing pollinator-friendly farms. The findings of this study can help farmers to consider best practices that guarantee sufficiently high numbers of pollinators and thus stable coffee harvests.

The word ‘biodiversity’ can have many different meanings to people, even if they have considerable knowledge and are aware of the phenomenon. Jalilova and Vacik (2012) studied local people's understanding of biodiversity in a country of which the valleys and forests can be characterised as extremely rich in biodiversity: Kyrgyzstan. Fruits and nuts are especially abundant and diverse in certain areas in Kyrgyzstan, but the biodiversity of walnut fruit trees is under pressure due to anthropogenic factors. Apart from occupation, the dependence on forest biodiversity was shown to have a strong influence on how biodiversity was perceived. Although local people were willing to conserve the forest biodiversity, most people also stated that their current socio-economic situation left them with no choice but to exploit the walnut forests in a way that can only be described as unsustainable. The findings by Jalilova and Vacik are all the more interesting when compared to results that were published earlier by Gos and Lavorel (2012). The authors studied people's perceptions and expectations of forest ecosystem services in the French Alps region and also related this to what it would mean for biodiversity hot spots. Similarly to Jalilova and Vacik (2012), the authors emphasized the importance of taking into account people's views on ecosystem services and biodiversity.

Perhaps the most studied ecosystem service is carbon sequestration. In order to provide reliable information of forests' potential to sequester carbon, it is crucial to estimate how the carbon stocks of forests have changed over time (Bala et al. 2007). Land use practices such as logging, agro-forestry and others have a considerable effect on forest ecology and diversity and consequently on its carbon stock (Edwards et al. 2010). Asase et al. (2012) compared the long-term effect of logging on tree diversity and carbon stocks in forests in Ghana. It was found that tree diversity of both smaller and larger trees was significantly higher in unlogged forests. In addition, the carbon stock was larger in unlogged forests as well, although it has to be noted that this large difference was not significant. More long-term studies like this should be conducted in order to better quantify the impact of logging and other land use practices on forest biodiversity and carbon sequestration.

Land use also has a large influence on plant density and diversity in the Ugandan savannah, as was shown by Kalema and Witkowski (2012). In a savannah ecosystem where charcoal production dominated, plant density was higher compared to areas that were used primarily for cultivation and grazing. The authors found not only that species composition and diversity was strongly influenced by land use, but also that unsustainable harvesting for charcoal and intensive land use resulted in generally low woody species diversity and richness. Considering the local people's dependence on the ecosystem for charcoal as well as other goods and services, these findings can help in developing more sustainable land use management.

A study by Akwetaireho and Getzner (2010) quantified the value of ecosystem services that naturally functioning wetlands near Lake Victoria (Uganda) provide. The fact that wetlands are vital for local households has been supported by many other studies, but it is important to realise that the contribution of services varies strongly per country and region, depending on the local socio-economic and environmental context. This is underlined by a new study by Adekola et al. (2012), who quantified the contribution of provisioning services to local livelihoods by a relatively small (1 km²) wetland in South Africa. Through a number of interesting data collection approaches, the authors were able to estimate that the wetland's contribution to local people's income represented about 15% of the average 2006 household income. Moreover, it was found that wetland services are essential for household subsistence and social activities like providing gifts to neighbours and relatives (values of these activities were not monetized). Unfortunately, it was also shown that due to a lack of alternative income sources, the wetland is being degraded, which in turn reduces the incomes generated by the wetland. More information on drivers of wetland degradation and how that impacts local communities can be found in earlier work by Adekola and Mitchell (2011) and Iftekhar (2008).

Forested areas are not only important on large spatial scales. In urban, densely populated areas forests also have the potential to provide important ecosystem services. Literature on urban ecosystem services, particularly local climate regulation, air quality regulation and carbon sequestration, is scarce due to various reasons. The uncertainties related to air quality regulation assessments (O₃, PM10 and NO _x , among others) are considerable, and therefore it is important to increase the number of highly detailed and relatively large scale studies that not only measure but also model air quality capture by vegetation. Studies in the United Kingdom (Beckett et al. 1998; Bealey et al. 2007) as well as the Chicago area (Nowak et al. 2006) are perhaps the best known. Carbon storage or sequestration has not been studied intensively in an urban context yet (see Pouyat et al. (2006) for an example from the United States), which is largely due to data unavailability (especially for the long term) and uncertainties related to fluctuating land cover (Lorenz and Lal 2009). A recent study by Martin et al. (2012) not only studied air quality regulation and carbon sequestration, but also compared the results between protected and maintained urban forests. Through a combination of field inventories and modelled analyses, the team was able to demonstrate the importance of protected areas even with the urban context. Carbon storage was nearly seven times higher in protected forest areas compared to maintained areas, and air pollution capture was eight times higher. Although the authors highlight the importance of protected or undisturbed stretches of forest in and around cities, it is important to note that even the contributions of maintained (less ‘wild’) trees and plants were considerable. Green infrastructure in general has the potential to provide important ecosystem services, and studies like the one done by Martin et al. (2012) illustrate that sound management and urban planning can only help to improve the health and livelihoods of city dwellers.

The issue of how quantification and valuation of marine ecosystem services can support the development of marine protected areas (MPAs) is relatively new. In previous issues, Busch et al. (2011) dealt with trade-offs between marine ecosystem services and offshore wind farming parks off the coast of northern Germany, and Guerry et al. (2012) modelled various marine ecosystem services to inform coastal and marine planning. In this issue, Rees et al. (2012) have added two important findings to the scientific literature. Their ‘service-orientated’ framework helps decision-makers to grasp the complex linkages between ecological functioning and indirect services, the latter being a category that is largely overlooked in marine spatial planning. However, the authors also emphasize that it is extremely difficult to isolate the contribution of individual ecosystem services because of the close linkages that can be found in the delivery pathway. Mapping and valuing individual indirect ecosystem services would offer a limited picture on how this and other closely related marine ecosystem services actually contribute to human well-being. From Rees et al. (2012) it becomes clear that numerous challenges remain in the assessment of MPAs' ecosystem functioning and, in line with that, the planning and management of MPAs.

Alexander P.E. van Oudenhoven and Rudolf S. de Groot

Environmental Systems Analysis Group, Wageningen

University, Wageningen, The Netherlands