Casey M. Ryan

Casey M. Ryan
The University of Edinburgh | UoE · School of GeoSciences

Ph.D Ecosystem Science

About

120
Publications
68,834
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Introduction
I'm interested in the socio-ecology of land use transitions, meaning the ways that land use change impacts livelihoods and ecosystems. I teach mixed methods, ecosystem ecology and run professional placements. My research mixes methods including remote sensing, ecological fieldwork and modelling, household surveys and interviews. I've applied these to understand a range of land use transitions in southern Africa and elsewhere.

Publications

Publications (120)
Article
Understanding the contribution of forests to poverty alleviation and human well-being has never been more important. The effects of the COVID-19 pandemic are erasing gains in poverty reduction achieved over the past several decades. At the same time, climate change is increasing the frequency of extreme weather events and natural disasters, especia...
Article
Full-text available
Data capturing multiple axes of tree size and shape, such as a tree's stem diameter, height and crown size, underpin a wide range of ecological research - from developing and testing theory on forest structure and dynamics, to estimating forest carbon stocks and their uncertainties, and integrating remote sensing imagery into forest monitoring prog...
Article
Data on tropical forests are in high demand. But ground forest measurements are hard to sustain and the people who make them are extremely disadvantaged compared to those who use them. We propose a new approach to forest data that focuses on the needs of data originators, and ensures users and funders contribute properly.
Article
Full-text available
Over the past decade, several global maps of above-ground biomass (AGB) have been produced, but they exhibit significant differences that reduce their value for climate and carbon cycle modelling, and also for national estimates of forest carbon stocks and their changes. The number of such maps is anticipated to increase because of new satellite mi...
Article
Millions of people rely on potentially sustainable harvesting for their income and energy. Yet specious assumptions about deforestation continue to drive ineffective bans on these practices. This occurs at the peril of the climate and the poor.
Article
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Land use is central to addressing sustainability issues, including biodiversity conservation, climate change, food security, poverty alleviation, and sustainable energy. In this paper, we synthesize knowledge accumulated in land system science, the integrated study of terrestrial social-ecological systems, into 10 hard truths that have strong, gene...
Article
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Soil moisture effects limit radar-based aboveground biomass carbon (AGBC) prediction accuracy as well as lead to stripes between adjacent paths in regional mosaics due to varying soil moisture conditions on different acquisition dates. In this study, we utilised the semi-empirical water cloud model (WCM) to account for backscattering from soil mois...
Article
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For monitoring and reporting forest carbon stocks and fluxes, many countries in the tropics and subtropics rely on default values of forest aboveground biomass (AGB) from the Intergovernmental Panel on Climate Change (IPCC) Guidelines for National Greenhouse Gas (GHG) Inventories. Default IPCC forest AGB values originated from 2006, and are relativ...
Article
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Non-pharmaceutical interventions (NPIs) such as social distancing and travel restrictions have been introduced to prevent the spread of the novel coronavirus (hereinafter Covid). In many countries of the Global South, NPIs are affecting rural livelihoods, but in-depth empirical data on these impacts are limited. We traced the differentiated impacts...
Article
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Land use change (LUC) is the leading cause of biodiversity loss worldwide. However, the global understanding of LUC's impact on biodiversity is mainly based on comparisons of land use endpoints (habitat vs non-habitat) in forest ecosystems. Hence, it may not generalise to savannas, which are ecologically distinct from forests, as they are inherentl...
Article
The alleviation of global poverty is a major objective of the 2030 UN Sustainable Development Goals (notably SDG1 “to end poverty in all its forms everywhere”). Many rural people experiencing poverty often rely on forests and tree-based systems, such as agroforestry, suggesting the existence of links between such systems and poverty outcomes. This...
Article
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Positive biodiversity‐ecosystem function relationships (BEFRs) have been widely documented, but it is unclear if BEFRs should be expected in disturbance‐driven systems. Disturbance may limit competition and niche differentiation, which are frequently posited to underlie BEFRs. We provide the first exploration of the relationship between tree specie...
Preprint
Full-text available
Land use change (LUC) is the leading cause of biodiversity loss worldwide. However, the global understanding of LUC's impact on biodiversity is mainly based on comparisons of land use endpoints (habitat vs non-habitat) in forest ecosystems. Hence, it may not generalise to savannas, which are ecologically distinct from forests, as they are inherentl...
Article
Full-text available
It is often asserted that secondary forests (SF) provide inferior forest-based ecosystem services (ES), but there is limited research to generalize this claim. Here, we review comparisons between ES provision in SFs and other land uses in shifting cultivation landscapes. We searched the peer-reviewed literature and selected only studies that compar...
Article
Tropical forests are the most diverse and productive ecosystems on Earth. While better understanding of these forests is critical for our collective future, until quite recently efforts to measure and monitor them have been largely disconnected. Networking is essential to discover the answers to questions that transcend borders and the horizons of...
Article
Full-text available
Global change has resulted in chronic shifts in fire regimes. Variability in the sensitivity of tree communities to multi-decadal changes in fire regimes is critical to anticipating shifts in ecosystem structure and function, yet remains poorly understood. Here, we address the overall effects of fire on tree communities and the factors controlling...
Article
The idea that tropical forest and savanna are alternative states is crucial to how we manage these biomes and predict their future under global change. Large-scale empirical evidence for alternative stable states is limited, however, and comes mostly from the multimodal distribution of structural aspects of vegetation. These approaches have been cr...
Article
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Tropical forest degradation is widely recognised as a driver of biodiversity loss and a major source of carbon emissions. However, in contrast to deforestation, the more gradual changes from degradation are challenging to detect, quantify, and monitor. Here we present a field protocol for rapid, area-standardised quantifications of forest condition...
Article
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The terrestrial forest carbon pool is poorly quantified, in particular in regions with low forest inventory capacity. By combining multiple satellite observations of synthetic aperture radar (SAR) backscatter around the year 2010, we generated a global, spatially explicit dataset of above-ground live biomass (AGB; dry mass) stored in forests with a...
Article
Emerging narratives call for recognising and engaging constructively with small-scale farmers who have a leading role in shaping the current irrigation dynamics in sub-Saharan Africa. This paper explores whether new irrigation data can usefully inform these narratives. It argues that, for a variety of reasons, official irrigation data in sub-Sahara...
Article
Full-text available
Aim Tree crowns determine light interception, carbon and water exchange. Thus, understanding the factors causing tree crown allometry to vary at the tree and stand level matters greatly for the development of future vegetation modelling and for the calibration of remote sensing products. Nevertheless, we know little about large‐scale variation and...
Article
Full-text available
Aim: Tree crowns determine light interception, carbon and water exchange. Thus, understanding the factors causing tree crown allometry to vary at the tree and stand level matters greatly for the development of future vegetation modelling and for the calibration of remote sensing products. Nevertheless, we know little about large‐scale variation and...
Article
Shifting cultivation systems of Southeast Asia are rapidly intensifying, especially through shortening of the fallow periods. It is typically assumed that intensification will result in a depletion of soil organic carbon (SOC) stocks, but existing estimates of carbon stocks in these systems are variable, and there is little certainty about the carb...
Article
The idea that tropical forest and savanna are alternative states is crucial to how we manage these biomes and predict their future under global change. Large-scale empirical evidence for alternative stable states is limited, however, and comes mostly from the multimodal distribution of structural aspects of vegetation. These approaches have been cr...
Chapter
Full-text available
This chapter reports on evidence about the role of forests and trees in alleviating poverty and supporting wider human well-being. It considers how, whether, where, when and for whom forests and trees are important in forest-poverty dynamics. We organise the evidence according to four possible relationships between forest products and ecosystem ser...
Article
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A major challenge for forest landscape restoration initiatives is the lack of quantitative evidence on how social factors drive environmental outcomes. Here we conduct an interdisciplinary quantitative analysis of the environmental and social drivers of tree biomass accumulation across 639 smallholder farms restoring native tree species in Mexico,...
Chapter
We describe the current land cover of the miombo woodlands and review both current and future drivers of change that may influence land cover in years to come. We also explore possible future ecological and socio-economic outcomes for the miombo in light of the projected futures for the miombo countries in particular, and for the continent in gener...
Preprint
Full-text available
Global change has shifted fire regimes, but the long-term consequences for ecosystems are uncertain because of variability in environmental conditions, fire types, and plant composition. We tested how fire-frequency manipulations of 16-64 years affect tree communities and traits using 374 plots from 29 sites on four continents. More frequently burn...
Preprint
Full-text available
The terrestrial forest carbon pool is poorly quantified, in particular in regions with low forest inventory capacity. By combining multiple satellite observations of synthetic aperture radar (SAR) backscatter around the year 2010, we generated a global, spatially explicit dataset of above-ground forest biomass (dry mass, AGB) with a spatial resolut...
Article
Full-text available
Seasonally dry woodlands are the dominant land cover across southern Africa. They are biodiverse, structurally complex, and important for ecosystem service provision. Species composition and structure vary across the region producing a diverse array of woodland types. The woodlands of the Huíla plateau in southwest Angola represent the extreme sout...
Article
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Environmental resources are often cited as important for households coping with hazards in the Global South. However, a recent large-scale analysis has challenged the narrative of ‘forest as safety net’. Clarifying this contradiction is important given the anticipated increase in the frequency of severe hazards due to climate change, and also becau...
Article
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A network to understand the changing socio-ecology of the southern African woodlands (SEOSAW): Challenges, benefits, and methods The SEOSAW partnership* This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly ci...
Article
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Intensifying land use is often seen as a corollary of improving rural livelihoods in developing countries. However, land use intensification (LUI) frequently has unintended impacts on ecosystem services (ES), which may undermine the livelihoods of the same people who could benefit from intensification. Poorer households are disproportionately depen...
Article
Agriculture is one of the main engines for prosperity and economic growth in Africa but effective agricultural strategies to support rural development and poverty alleviation are not yet identified. While state investment in the small-scale farming sector is minimal, and the medium-scale “emergent” household farm sector remains underrepresented, la...
Article
Forest and woodland resources can play a key role in rural livelihoods in the Global South, making it critical to understand what forest change could mean for rural wellbeing. Calculating environmental income has become a popular method of highlighting the importance of environmental resources in livelihoods, but few studies have quantified both pr...
Data
This dataset includes data collected as part of the Abrupt Changes in Ecosystem Services (ACES) project on the composition, income (including consumption and sale of environmental resources), ownership of assets (e.g. farming equipment, household furnishings and own transport) and wellbeing of respondent households in rural Mozambique. Data are als...
Article
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Context Humans and elephants are major disturbance agents in the African savanna woodlands. While both species remove trees, humans selectively harvest larger stems, which are less vulnerable to elephants. Increasing human pressures raise the question of how the altered disturbance regime will modify woodland structure, and in turn biodiversity and...
Article
Aim In tropical Africa, savannas cover huge areas, have high plant species richness and are considered as a major natural resource for most countries. There is, however, little information available on their floristics and biogeography at the continental scale, despite the importance of such information for our understanding of the drivers of speci...
Research
Full-text available
Sustainable agricultural intensification appears in the United Nations Sustainable Development Goals (SDGs) as a key strategy for ending hunger (SDG2) and achieving sustainable use of terrestrial ecosystems (SDG15). Yet, it is not clear whether such twin benefits - for both human wellbeing and ecosystems - are actually achieved, especially in low a...
Article
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The Bateke Plateau in the Republic of Congo is one of the last frontiers for ecology, with little known about its floristics and physiognomy. Despite occupying 89,800 km² and its importance for local livelihoods, its ecology and ecosystem functions are poorly understood. Situated on Kalahari sands, the Bateke has a complex evolutionary history, mai...
Article
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Sub-Saharan Africa's charcoal sector is rarely considered a mechanism for rural development or poverty alleviation; instead, current regulations often marginalise rural producers. The development of a sustainable sector, that does not further marginalise rural populations, is restricted by limited understanding of these stakeholders. We assess the...
Article
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Land use carbon fluxes are major uncertainties in the global carbon cycle. This is because carbon stocks, and the extent of deforestation, degradation and biomass growth remain poorly resolved, particularly in the densely populated savannas which dominate the tropics. Here we quantify changes in aboveground woody carbon stocks from 2007-2010 in the...
Article
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Globally, marginal lands, or less favored areas (LFAs), cover significant areas with large human populations, yet are relegated in policy making due to their perceived low agricultural value and a lack of information about other ecosystem services (ES) they may provide. Here we applied a simple, inclusive and qualitative ES inventory and Bayesian B...
Article
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In the version of this Review originally published, the top heading in the first column of Fig. 2 was mistakenly written ‘Food poisoning’; it should have read ‘Food provisioning’. This has now been corrected.
Article
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Land-use intensification in agrarian landscapes is seen as a key strategy to simultaneously feed humanity and use ecosystems sustainably, but the conditions that support positive social-ecological outcomes remain poorly documented. We address this knowledge gap by synthesizing research that analyses how agricultural intensification affects both eco...
Article
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African savannas and dry forests represent a large, but poorly quantified store of biomass carbon and biodiversity. Improving this information is hindered by a lack of recent forest inventories, which are necessary for calibrating earth observation data and for evaluating the relationship between carbon stocks and tree diversity in the context of f...
Article
The African land system is undergoing rapid change, and novel approaches are needed to understand the drivers and consequences of land use intensification. Human Appropriation of Net Primary Productivity (HANPP) is a powerful indicator of land use intensity, but has rarely been calculated at high spatial resolutions. Based on data from six villages...
Article
Full-text available
Charcoal is an important source of energy and income for millions of people in Africa. Its production often drives forest degradation and deforestation which have impacts on the local people that remain poorly understood. We present a novel methodology for analysing the contribution of woodland ecosystem services (ES) to rural well-being and povert...
Article
Agriculture needs to reduce inputs of inorganic fertilizers and close the loop on nutrients that can otherwise become environmental pollutants. This can be achieved by promoting recycling of nutrients within the agricultural landscape. We investigated the extent to which plants found in riparian buffer zones have the potential to provide nutrients...
Data
This dataset comprises 259 smallholder agricultural field surveys collected from twenty-six villages across three Districts in Mozambique, Africa. Surveys were conducted in ten fields in each of six villages in Mabalane District, Gaza Province, ten villages in Marrupa District, Niassa Province, and ten villages in Gurue District, Zambezia Province....
Article
Full-text available
Monitoring is a key aspect of payments for ecosystem services (PES) schemes, providing a basis for payments. PES monitoring however presents challenges, including in balancing technical accuracy with cost, local equity and legitimacy. This is particularly true in smallholder carbon PES, where managers have limited resources and capacity. Here we ex...
Article
Full-text available
Charcoal production constitutes a key ecosystem service in Mozambique, with an estimated market value of US$400 million a year. Due to the central role the charcoal industry plays in local livelihoods, availability of suitable wood for charcoal production has decreased because of changes in land use and land cover (LULC). This paper applied a proba...