Pollination ecosystem services in South African agricultural systems

Abstract

Insect pollinators, both managed and wild, have become a focus of global scientific, political and media attention because of their apparent decline and the perceived impact of this decline on crop production. Crop pollination by insects is an essential ecosystem service that increases the yield and quality of approximately 35% of crops worldwide. Pollinator declines are a consequence of multiple environmental pressures, e.g. habitat transformation and fragmentation, loss of floral resources, pesticides, pests and diseases, and climate change. Similar environmental pressures are faced in South Africa where there is a high demand for pollination services. In this paper, we synthesise data on the importance of different pollinators as a basis for services to South African crops and on the status of managed honeybees. We also focus on insect pollination services for the Western Cape deciduous fruit industry, which is worth ZAR9800 million per year and is heavily reliant on pollination services from managed honeybees. We discuss landscape and regional level floral resources needed to maintain sufficient numbers of managed honeybee colonies. In summary, the available literature shows a lack of data on diversity and abundance of crop pollinators, and a lack of longterm data to assess declines. We highlight key areas that require research in South Africa and emphasise the critical role of floral resource availability at the landscape and regional scale to sustain pollinators. We conclude that understanding the dynamics of how floral resources are used will help inform how landscapes could be better managed in order to provide long-term sustainable pollination services.

Risk hotspots for terrestrial plant invaders under climate change at the global scale

“…Human impact, including human activity in CE ecoregions, may also aid the expansion of TPIs to risk hotspots under climate change (Spear et al 2013;Melin et al 2014). Human activities can provide invasion pathways for TPIs under climate change Donaldson et al 2014;Seebens et al 2015).…”

“…Human activities can provide invasion pathways for TPIs under climate change Donaldson et al 2014;Seebens et al 2015). Globalization facilitates the spread of TPIs as international commerce develops and as plants are introduced for horticulture or commercial purposes (Perrings et al 2005;Bradley et al 2010b;Donaldson et al 2014;Melin et al 2014;Seebens et al 2015). For example, climate change can increase the invasion risk of Lonicera japonica, a common invasive horticultural vine in the USA (www.issg.org).…”

“…Furthermore, intensive anthropogenic activities greatly increase the chances of increasing pathways for TPIs (Spear et al 2013). Hence, we need to integrate introduction dynamics into the management planning for preventing intentional or accidental introduction or dispersal of TPIs (Bradley 2010;Donaldson et al 2014;Melin et al 2014).…”

Western honey bee management for crop pollination

“…In Africa, the use of managed honeybee has been reported only in Tunisia and South Africa (Barbouche, 2009;Allsopp, 2005;Melin et al, 2014). However, this practice has been reported in some scientific experiments in Democratic Republic of Congo with the African melon, Cucumeropsis mannii (Ndola, 2015), in Benin and Ghana with the cashew, Anacardium occidentale (Aidoo et al, 2015) in order to assess its effect on crop yield and farmers income.…”

Modelling plant invasion pathways in protected areas under climate change: implication for invasion management

“…For example, emerging economies in mega-diverse regions expect a strong increase in the number of naturalized plants by 2030(Seebens et al, 2015. Anthropogenic activities, such as agriculture and forestry in regions surrounding PAs, further promote the introduction of IPS Melin et al, 2014;McConnachie et al, 2015). Intensive anthropogenic activities inside PAs and in adjacent areas greatly increase the number of pathways for IPS (Spear et al, 2013;McConnachie et al, 2015).…”