Assessing the effects of agroforestry practices on biological control potential in kale (Brassica oleracea acephala) plantations in Western Kenya

Agricultural intensification and extension at the expense of forests are known to have a negative impact on biodiversity and ecosystem services. In Sub-Saharan Africa (SSA), agriculture provides livelihoods for most of the population and forestry is an important additional income. Agroforestry practices may help to compensate for loss of biodiversity. Pests are an important constraint to agricultural production and their biological control is affected by environmental degradation. Management practices such as alteration of the field micro-environment and increases in landscape complexity can be efficient non-chemical methods for reducing pest damage. In this study, I examine how the implementation of agroforestry influences biological control in kale (Brassica oleracea var. acephala) plantations in Western Kenya. Twenty fields, either shaded or open, were selected at four settlements in the Trans-Nzoia district of Kenya. Landscape complexity was defined as the percentage of wooded vegetation within a 50 m radius. Pesticide use, mulching practices and the amount of rainfall were recorded as additional explanatory variables. Predation was assessed by (1) egg removal rates, (2) bird exclusion, and (3) predation marks on plasticine caterpillars. Activity density of ground-dwelling predators was assessed with pitfall traps and foliage-dwelling pests and predators were counted on the plants. Aphid parasitism rates were also estimated by counting live aphids and aphid mummies. The effect of shade and landscape complexity, pesticide use, mulching and rainfall was tested by running generalized linear models and selecting the best models based on Akaike Information Criterion adjusted for small sample-sizes. Presence of shade-trees at the local field level was found to be effective in reducing population of both surveyed pests and in increasing aphid parasitism rates and caterpillar predation by birds. Neither the proportion of wooded vegetation in the landscape nor the interaction between local shade and landscape scale tree cover were retained as significant explanatory variables. However, pesticides negatively influenced aphid abundances, predator abundances and egg removal rates while positively influencing caterpillar populations. I conclude that in kale agro-forestry systems of Western Kenya, local management of shade is effective in increasing biological control of pests, but I found no evidence that the proportion of trees in the landscape is important. This can be explained by the small-scale of the analysis and should be investigated with larger scale and stronger differences between agroforestry versus conventional systems. The negative effect of pesticides is also important to note and should be further investigated in order to improve the sustainability of farming practices

Home food gardening : benefits and barriers during the COVID-19 pandemic in Santiago, Chile

The recent COVID-19 pandemic has changed the way people live in an unprecedented way. This includes severe impacts on people's health and wellbeing such as stress, reduced physical activity and loneliness due to confinement. In parallel, people had to find ways to secure their food, with fresh food especially scarce in some regions due to lockdowns and restricted flow of goods. As in previous massive crises, the practice of home food gardening seemed to have increased during this pandemic. Yet we largely do not know which parts of society took to home food gardening, in which urban setting home food gardening was practiced, and to which extent this practice contributed to people's daily livelihoods during the pandemic. In this case study we explore (a) who practices home food gardening, (b) the garden characteristics, and (c) the main perceived benefits and barriers bound to home food gardening during the pandemic. We set up an online questionnaire targeted at the population of Santiago de Chile, for which we received 305 responses. Our results clearly show that the possibility of being in contact with nature and feeling less stress through practicing home food gardening were the most significant perceived benefits, while lack of or inadequate space to garden and limited knowledge on home food gardening were the main barriers. These findings highlight for the specific context of a metropolitan region in South America that access to gardens and green space could contribute to a just urban society. Likewise, the practice of home food gardening can be a relevant tool to cope with the adverse consequences of the pandemic by informing public initiatives to promote healthier lifestyles during this and future crises contexts and also in the awaited “ordinary” times.German Research Foundation (DFG

Unpacking stakeholder perceptions of the benefits and challenges associated with urban greenspaces in Sub-Saharan Africa

Urban greenspaces underpin ecosystem service provision in cities and are therefore indispensable for human well-being. Nevertheless, they are increasingly disappearing from cities in Sub-Saharan Africa. Understanding how the stakeholders influencing urban greenspace management perceive the benefits provided by urban greenspaces and the challenges to its conservation and management is critical for reversing this trend. Using Malawi’s capital city, Lilongwe, as a case study, we conducted 44 semi-structured interviews to explore the profiles and perceptions of stakeholders who currently hold influence over greenspace planning, conservation and management. Stakeholders with influence over urban greenspace management described the main focus of their organisation as relating to urban planning, natural resources protection and management, development work, or the hospitality business sector. Critically, only a third of all stakeholders focused on natural resources protection and management. Stakeholders had nuanced and varied appreciations of the benefits that greenspaces provide. Regulation and maintenance ecosystem services, as well as cultural services were frequently mentioned. However, provisioning services were mostly mentioned by those in development work. Stakeholders also identified an additional suite of societal benefits that do not directly map onto ecosystem service frameworks, such as the generation of financial income and the provision of employment opportunities. Challenges identified as hampering the planning, conservation and management of greenspaces included inappropriate urbanisation, lack of coordination and participation, and population growth. Lack of coordination was however not widely acknowledged among those focusing on natural resources protection, who conversely identified population growth more often than any other groups. Highlighting how stakeholders with varying priorities perceive ecosystem services a first step towards improving greenspaces management both for their better acceptation and for improving their potential for biodiversity conservation. Specifically, we bring attention to need for stakeholders working with natural resources protection to recognise more the need for collaborations and engagement. Additional research is also necessary to understand how those different perspectives might be integrated into ongoing processes and procedures to manage greenspaces in Sub-Saharan Africa

Meeting sustainable development goals via robotics and autonomous systems

Robotics and autonomous systems are reshaping the world, changing healthcare, food production and biodiversity management. While they will play a fundamental role in delivering the UN Sustainable Development Goals, associated opportunities and threats are yet to be considered systematically. We report on a horizon scan evaluating robotics and autonomous systems impact on all Sustainable Development Goals, involving 102 experts from around the world. Robotics and autonomous systems are likely to transform how the Sustainable Development Goals are achieved, through replacing and supporting human activities, fostering innovation, enhancing remote access and improving monitoring. Emerging threats relate to reinforcing inequalities, exacerbating environmental change, diverting resources from tried-and-tested solutions and reducing freedom and privacy through inadequate governance. Although predicting future impacts of robotics and autonomous systems on the Sustainable Development Goals is difficult, thoroughly examining technological developments early is essential to prevent unintended detrimental consequences. Additionally, robotics and autonomous systems should be considered explicitly when developing future iterations of the Sustainable Development Goals to avoid reversing progress or exacerbating inequalities

A global horizon scan of the future impacts of robotics and autonomous systems on urban ecosystems

Technology is transforming societies worldwide. A major innovation is the emergence of robotics and autonomous systems (RAS), which have the potential to revolutionize cities for both people and nature. Nonetheless, the opportunities and challenges associated with RAS for urban ecosystems have yet to be considered systematically. Here, we report the findings of an online horizon scan involving 170 expert participants from 35 countries. We conclude that RAS are likely to transform land use, transport systems and human–nature interactions. The prioritized opportunities were primarily centred on the deployment of RAS for the monitoring and management of biodiversity and ecosystems. Fewer challenges were prioritized. Those that were emphasized concerns surrounding waste from unrecovered RAS, and the quality and interpretation of RAS-collected data. Although the future impacts of RAS for urban ecosystems are difficult to predict, examining potentially important developments early is essential if we are to avoid detrimental consequences but fully realize the benefits

Understanding the conservation potential of urban greenspaces in Sub-Saharan Africa

With more than half of the world population living in cities, land-use changes associated with urban growth are one of the main threats to biodiversity. However, it is generally accepted that urban greenspaces can mitigate this threat by providing habitat for a wide variety of species as well as improving urban liveability through ecosystem services ranging from recreation to food or shade provision. In Africa, cities are expanding at the fastest rates globally and increasingly encroach on biodiversity hotspots. Yet we know little about their potential for maintaining biodiverse greenspaces, their ability to provide ecosystem services, the social context shaping their governance or the preferences people hold for them. This thesis begins to fill those gaps by assessing how ecosystem services are maintained, governed and valued in Sunyani and Techiman, two fast-growing cities in Ghana. Small African cities contain greenspaces that can maintain pollinator populations of similar abundances to those found in the surrounding landscapes, albeit with variations linked to greenspace management and shifts in community structure. However, the social interactions at play in the urban landscape threaten such greenspaces. Social network analysis revealed that the stakeholders with the greatest influence on their retention have mixed attitudes towards them, contrasting with the fact that stakeholders generally value the ecosystem services provided by greenspaces. Nevertheless, perceptions of ecosystem services are diverse, highlighting the need to identify particular services around which conservation efforts and messaging can build consensus across society, while simultaneously targeting particular messages to certain influential groups. Doing so may help promote urban greenspace conservation across residents, businesses, civil society and public authorities. By taking an inter-disciplinary approach to urban ecosystem services, this thesis provides a holistic understanding of the potential and challenges facing urban greenspace conservation in the rarely studied context of small urban areas of Sub-Saharan African