Pollination and food security
Nature provides ecosystem services that make life possible here on earth. There are four types of ecosystem services; provisioning, supporting, cultural and regulating services. In this newsletter issue, we will highlight pollination, one of the regulating ecosystem services essential for food security, food diversity and human nutrition.
What is pollination?
The important priority of every living organism is to creating offspring for the next generation. Plants need to produce fruits and seeds to make offspring, a new plant. Seeds /fruitscan only be produced when pollen grains are transferred from the anther, which is the male part of the flower, to the stigma, a female part of the same species. This process is called pollination.
How does pollination occur?
We know that plants are not able to move from one place to another, so how does pollen get transferred from anther to the stigma? Flowers rely on agents to move pollen from the anther to the stigma of the same or different plant but of the same species. These agents can include wind, water, birds, insects, butterflies, bats, and other animals that visit flowers. Living animals that can transfer pollen are called pollinators. The pollinator is often eating or collecting pollen for its protein and other nutritional characteristics or it is sipping nectar from the flower when pollen grains attach themselves to the animal’s body. Pollination can therefore be called a symbiotic relationship between a plant and pollinator.
Types of pollination
Two types of pollination exist which are cross-pollination and self-pollination. Cross-pollination occurs when pollen grains are transferred from the anther to the stigma of a different plant whereas, in a self-pollination, the transfer of pollen grains is from an anther to a stigma of the same flower or plant. Each of the pollination types has advantages and disadvantages, which we are not going to look at in this issue. What is important to note is that self-pollination occurs in species with closed flowers, therefore, limiting access to pollination agents to flower’s sexual structures.
Each plant posses specific floral characteristics that favour a specific or a group of pollination agents. This includes; flower type, shape, color, odor, nectar, and structure. These floral characteristics and their relationships with the favoured pollinators are called pollination syndromes. Pollination syndromes are a symbiotic relationship between the plants and the agents or animals in which both benefit. Animals forage on the flowers for carbohydrates (in nectar) and proteins (in pollen grains), which are the rewards. On the other hand, the plant provides animals with nectar and pollen to guarantees its pollination and reproduction.
The following pollination syndromes are recognized: cantharophily (beetles), melittophily (bees), myophily (by flies), psychophily (butterflies and moths), chiropterophily (bats), and ornithophily (birds). In these pollination syndromes, the pollen grains are attached to some parts of the animals and become brushed onto the stigma.
Pollination and food security
Pollination is an important ecosystem service for food production therefore, global food security. However, animal pollinators are currently threatened by habitat destruction and unsustainable agricultural practices such as intensification and pesticide misuse, risking global food security. The current increase in the human population (projected to be 9 – 10 billion by 2050) will put more pressure on the food production system. This will have a negative effect on future food security, especially in developing countries like Tanzania.
A balance between plants and pollination agents in ecosystems was maintained for centuries and has been key to sustainable food production and a healthy ecosystem. But the current surge in monoculture farmland, expanding agricultural land wildfires and diseases, the balance is constantly disturbed. The Sustainable Development Goal 2, Zero Hunger is highly dependent on effective pollination and pollinators’ conservation. According to the United Nations, about 2 billion people in the world did not have regular access to safe, nutritious and sufficient food in 2019. With the ongoing destruction of ecosystems and unsustainable agricultural practices, there is little hope that the world will achieve the Zero Hunger target by 2030. Under the business as usual scenario, the number of people affected by hunger would surpass 840 million by 2030.
Nature Tanzania’s Initiatives
Nature Tanzania being a bird focussed NGO, is committed to the conservation and protection of avian pollinators in the country. This includes supporting research on avian pollinators to understand their status and trends. Key to this is the Biodiversity Monitoring (BiMO) project in the East Usambara Mountains, a Nature Tanzania’s project implemented in partnership with the Department of Zoology and Wildlife Conservation of the University of Dar es Salaam.
The project includes two objectives capacity building (bird ringing and monitoring training) and biodiversity monitoring including the avian pollinators. The first bird ringing and monitoring training program was conducted in September and October 2020. Data on avian pollinators were collected by trainees. This will form a baseline of avian pollinators of Eastern Arc Mountain and inform conservation efforts.
To reach the Zero Hunger target by 2030, we need to consider environment-friendly agricultural systems for sustainable food production. This will not be achieved if the pollinators are not protected and conserved. There is a need for advocating and supporting best agricultural management practices that support wild pollinators especially encouraging plant diversity, and controlling pesticide use. We also need to conserve and protect natural forests as they are an important habitat for pollinators, providing refuge and food.
We welcome partners for the BiMO project in the East Usambara Mountains and also the conservation of Long-billed Forest Warbler.
Awoke TG. (2014). Vertebrates’ pollination in angiosperm: Floral syndrome, mode of pollen transfer and pollinators specialization. Research Journal of Agricultural and Environmental Management. 2014;3(12):625-631
Muchhala N, Caiza A, Vizuete JC, Thomson JD. A generalized pollination system in the tropics: Bats, birds and Aphelandra acanthus. Annals of Botany. 2008;103:1481- 1487. DOI: 10.1093/aob/mcn260
Bailes EJ, Ollerton J, Pattrick JG, Glover BJ. How can an understanding of plant–pollinator interactions contribute to global food security? Current Opinion in Plant Biology. 2015;26:72-79.
Nielsen A, Andreas TR, Rinvoll Brysting K. Effects of competition and climate on a crop pollinator community. Agriculture Ecosystems and Environment. 2017;247:253-260.
van der Sluijs, J.P., Vaage, N.S. Pollinators and Global Food Security: the Need for Holistic Global Stewardship. Food ethics 1, 75–91 (2016).