Population ecology and phenological responses of food-producing forest trees to climate change: implications for rural food security

Asuk, Sijeh Agbor ORCID: 0000-0002-4156-0202 (2023). Population ecology and phenological responses of food-producing forest trees to climate change: implications for rural food security. University of Birmingham. Ph.D.

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Abstract

Tropical rainforests are important ecosystems that provide numerous benefits to humans and are home to a rich diversity of flora and fauna. The Afrotropical rainforests are particularly valuable due to their high biodiversity and provision of essential services such as carbon sequestration and water regulation. However, these forests are facing unprecedented threats from various anthropogenic activities, including habitat loss, fragmentation, degradation, and climate change. While studies have focused on the global and regional impacts of these activities on tropical forests, small-scale, less intense, human activities like foraging are modifying the forest in ways that have not been fully evaluated. This doctoral research project aims to address this knowledge gap by exploring the impact of low-intensity anthropogenic activities and environmental drivers on the species composition, structure, and biodiversity of the Oban rainforest in Nigeria. The project comprises four interconnected research objectives: (1) to analyse the impact of human utilization of tree species for food on the diversity, composition, and structure of food-producing and non-food producing tree species; (2) to assesses how human foraging affects regional-scale tree species biodiversity patterns in Nigeria and Cameroon; (3) to evaluate the effect of climate variability on forest phenology (EVI) in Oban rainforest between 2002 and 2022 and (4) to provide baseline monitoring data on the reproductive phenology (time of budding, flowering and fruiting) of tree species in Oban Forest between May 2020 to May April 2022. Findings show that low-intensity human activities such as foraging can significantly impact tree species assemblages in tropical forests, particularly for edible species, potentially leaving long-lasting footprints. The research highlights the complex interplay that environmental, spatial, and human factors have in shaping tree species dissimilarity in the Nigeria-Cameroon forest region, providing valuable insights on the need for further research to better understand the extent and nature of human impacts on regional forest composition. The remote sensing data shows that precipitation is a as the major driver of changes in EVI with up to seven months lagged response. The timing of the peak in EVI showed potential implications for the livelihoods of forest-dependent communities who rely on forest resources for food and income. The seasonal trend in fruit production, occurred in July and August in the first cycle and in July in the second growing season. Continuous production of flowering buds and flowers was observed throughout the year without indicating a clear seasonal cycle. The results highlight the importance of considering the influence of human activities in understanding the dynamics of tropical forests, and further research is needed to explore the different possibilities and validate the findings fully. There is a need to address some key unknowns and uncertainties in the study, such as the impact of extreme weather events and other variables influencing the tropical forest phenological cycle. Collaborating with local communities, policymakers, and modellers could help address these limitations and provide a more comprehensive understanding of the phenological cycle in the Oban Forest. Long-term monitoring of the reproductive phenology of food-producing tree species is an essential approach to generating ground-based data to better understand the response of phenology to environmental and other factors.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):

Supervisor(s)	Email	ORCID
Kettridge, Nicholas	UNSPECIFIED	orcid.org/0000-0003-3995-0305
Sadler, Jon	UNSPECIFIED	orcid.org/0000-0003-0443-4458
Matthews, Thomas	UNSPECIFIED	orcid.org/0000-0002-7624-244X
Pugh, Thomas	UNSPECIFIED	orcid.org/0000-0002-6242-7371