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Introduction
Professor in Forest Landscape Restoration, Newcastle University, UK. Focus: rural tropical landscapes (primarily Eastern Africa, but also SE Asia); Agroforestry as a conservation and management intervention. Tools: Land systems science, Restoration science, Landscape Ecology, Biodiversity science.
Current institution
Additional affiliations
May 2020 - June 2024
Position
- Research Associate Landscape Ecology
August 2009 - present
Publications
Publications (112)
Background
Riparian zones are vital transitional habitats that bridge the gap between terrestrial and aquatic ecosystems. They support elevated levels of biodiversity and provide an array of important regulatory and provisioning ecosystem services, of which, many are fundamentally important to human well-being, such as the maintenance of water qual...
Background: Above-ground biomass (AGB) and its temporal dynamics are key parameters of forest ecosystems, related to their resilience and capacity to fix atmospheric carbon. AGB is related to species richness, composition, forest structure, soils and climate. In human-modified landscapes, fragmentation and human pressure may change the nature of th...
Lianas (woody vines and climbing monocots) are increasing in abundance in many tropical forests with uncertain consequences for forest functioning and recovery following disturbances. At a global scale, these increases are likely driven by disturbances and climate change. Yet, our understanding of the environmental variables that drive liana preval...
Lianas are important to rainforest ecosystems but often impede tree growth and increase tree mortality and stem damage after disturbances that favor their growth. Understanding how lianas affect biomass recovery and rates of carbon sequestration following disturbance is therefore of crucial importance. In this study, we determine how a tropical for...
Logged and disturbed forests are often viewed as degraded and depauperate environments compared with primary forest. However, they are dynamic ecosystems¹ that provide refugia for large amounts of biodiversity2,3, so we cannot afford to underestimate their conservation value⁴. Here we present empirically defined thresholds for categorizing the cons...
Lianas, or woody vines, are key components of many tropical forests and can have substantial impacts on the dynamics and functioning of these important ecosystems. Their competition with trees for resources, in particular light, can hamper the recovery of forests from disturbances. Yet, it is unclear how forest disturbance interacts with liana–tree...
Bornean Ground-cuckoo Carpococcyx radiceus (sometimes Carpococcyx radiatus) is a ground�dwelling bird endemic to the island of Borneo, first described by Temminck in 1832 (Pontianak district, West Borneo) (Temminck 1832, Long & Collar 2002). It is a large (60 cm) bird, with a purple-glossed black head, a green mantle and back with purple gloss and...
Lianas are common in tropical forests, where they influence forest dynamics, thus impacting the global carbon sink, with implications for climate change mitigation. Despite their increasing competitiveness with trees at the global scale, robust measurements of liana aboveground biomass (AGB) have been limited. Here we use data from destructive samp...
Land-use change for crop production is one of the key drivers of habitat loss and fragmentation and consequently biodiversity loss and change in tropical regions. This may impact biodiversity-regulated ecosystem services; birds are important to crop health regulating services (e.g. seed dispersal, pest control) and disservices (e.g. seed predation,...
The functional stability of ecosystems depends greatly on interspecific differences in responses to environmental perturbation. However, responses to perturbation are not necessarily invariant among populations of the same species, so intraspecific variation in responses might also contribute. Such inter-population response diversity has recently b...
Growing evidence suggests that liana competition with trees is threatening the global carbon sink by slowing the recovery of forests following disturbance. A recent theory based on local and regional evidence further proposes that the competitive success of lianas over trees is driven by interactions between forest disturbance and climate. We prese...
Background and context
The scale of land degradation worldwide has led to nearly one billion hectares committed to restoration globally. However, achieving such restoration targets will necessitate complex trade-offs against limited time, competing knowledge, costs, resources and varying stakeholder and societal preferences. Participatory scenarios...
The discourse of transformation, as currently adopted in policy arenas, has given scarce attention to diverse knowledges, plural pathways, and politics. Narratives about change and agricultural transformation in African landscapes are diverse. However, failure to recognise diversity among narratives of the predominant food producers—smallholder far...
Agroforestry systems have the potential to increase carbon and nitrogen content of the soil. The increase of these elements promises agroforestry to be a useful practice for mitigating climate change, through an increased sequestration of carbon, and improving the food security of the area it is implemented. This is particularly important for Niger...
Species sensitivity to forest fragmentation varies latitudinally, peaking in the tropics. A prominent explanation for this pattern is that historical landscape disturbance at higher latitudes has removed fragmentation-sensitive species or promoted the evolution of more resilient survivors. However, it is unclear whether this so-called extinction fi...
The scale of land degradation worldwide has led the UN to declare the Decade of Ecosystem Restoration and movements such as the Bonn Challenge (https://www.bonnchallenge.org/), have placed ecological restoration on the global policy agenda. Achieving such ambitious policy targets and restoration goals will necessitate complex trade-offs against lim...
The scale of land degradation worldwide has led the UN to declare the Decade of Ecosystem Restoration and movements such as the Bonn Challenge (https://www.bonnchallenge.org/), have placed ecological restoration on the global policy agenda. Achieving such ambitious policy targets and restoration goals will necessitate complex trade-offs against lim...
The scale of land degradation worldwide has led the UN to declare the Decade of Ecosystem Restoration and movements such as the Bonn Challenge (https://www.bonnchallenge.org/), have placed ecological restoration on the global policy agenda. Achieving such ambitious policy targets and restoration goals will necessitate complex trade-offs against lim...
The scale of land degradation worldwide has led the UN to declare the Decade of Ecosystem Restoration and movements such as the Bonn Challenge (https://www.bonnchallenge.org/), have placed ecological restoration on the global policy agenda. Achieving such ambitious policy targets and restoration goals will necessitate complex trade-offs against lim...
The scale of land degradation worldwide has led the UN to declare the Decade of Ecosystem Restoration and movements such as the Bonn Challenge (https://www.bonnchallenge.org/), have placed ecological restoration on the global policy agenda. Achieving such ambitious policy targets and restoration goals will necessitate complex trade-offs against lim...
The scale of land degradation worldwide has led the UN to declare the Decade of Ecosystem Restoration and movements such as the Bonn Challenge (https://www.bonnchallenge.org/), have placed ecological restoration on the global policy agenda. Achieving such ambitious policy targets and restoration goals will necessitate complex trade-offs against lim...
Effective restoration planning tools are needed to mitigate global carbon and biodiversity crises. Published spatial assessments of restoration potential are often at large scales or coarse resolutions inappropriate for local action. Using a Tanzanian case study, we introduce a systematic approach to inform landscape restoration planning, estimatin...
Certified community forests combine local governance with forest certification and aim to serve multiple objectives including forest protection, restoration, human wellbeing and equitable governance. However, the causal pathways by which they impact these objectives remain poorly understood. The ability of protected area impact evaluations to ident...
There has never been a more pressing and opportune time for science and practice to collaborate towards restoration of the world's forests. Multiple uncertainties remain for achieving successful, long-term forest landscape restoration (FLR). In this article, we use expert knowledge and literature review to identify knowledge gaps that need closing...
The science guiding design and evaluation of restoration interventions in tropical landscapes is dominated by ecological processes and outcomes and lacks indicators and methods that integrate human wellbeing into the restoration process. We apply a new systems approach framework for tree restoration in forest-agricultural landscapes to show how thi...
Tropical and subtropical regions shelter high levels of biodiversity. A combination of biological, environmental and anthropogenic factors influences tree community diversity and composition. Here, we use data from the IFFSC project to test the effect of conspecific and heterospecific density dependence, canopy cover and distance to edge on sapling...
Millions of people rely on nature-rich farming systems for their subsistence and income. The contributions of nature to these systems are varied and key to their sustainability in the long term. Yet, agricultural stakeholders are often unaware or undervalue the relevance of those contributions, which can affect decisions concerning land management....
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 auton...
Background
The scale of land degradation worldwide has led the UN to declare the Decade of Ecosystem Restoration and movements such as the Bonn Challenge ( https://www.bonnchallenge.org/ ), have placed ecological restoration on the global policy agenda. Achieving such ambitious policy targets and restoration goals will necessitate complex trade-off...
Logging and habitat conversion create hotter microclimates in tropical forest landscapes, representing a powerful form of localised anthropogenic climate change. It is widely believed that these emergent conditions are responsible for driving changes in communities of organisms found in modified tropical forests, although the empirical evidence bas...
The Atlantic Forest, a global biodiversity hotspot, has changed dramatically due to land use pressures causing deforestation, degradation, and forest fragmentation. A major challenge is to understand and potentially mitigate the consequences of these changes, for the capacity of forests to deliver essential environmental services to rural areas. He...
The Atlantic Forest, a global biodiversity hotspot, has changed dramatically due to land 12 use pressures causing deforestation, degradation, and forest fragmentation. A major challenge is 13 to understand and potentially mitigate the consequences of these changes, for the capacity of 14 forests to deliver essential environmental services to rural...
Lianas are woody vines, rooted in the soil, and supported physically by trees. Lianas contribute to forest ecosystem functioning globally, but especially in the tropics and subtropics. However, prolific liana growth following heavy disturbance frequently affects subsequent recovery of forest tree diversity, biomass, structure, and function. Underst...
Decades of research suggest that species richness depends on spatial characteristics of habitat patches, especially their size and isolation. In contrast, the habitat amount hypothesis predicts that: 1) species richness in plots of fixed size (species density) is more strongly and positively related to the amount of habitat around the plot than to...
Vulnerability to habitat fragmentation
Habitat fragmentation caused by human activities has consequences for the distribution and movement of organisms. Betts et al. present a global analysis of how exposure to habitat fragmentation affects the composition of ecological communities (see the Perspective by Hargreaves). In a dataset consisting of 448...
Tropical landscapes are changing rapidly due to changes in land use and land management. Being able to predict and monitor land use change impacts on species for conservation or food security concerns requires the use of habitat quality metrics, that are consistent, can be mapped using above-ground sensor data and are relevant for species performan...
The assembly of species communities at local scales is thought to be driven by environmental filtering, species interactions and spatial processes such as dispersal limitation. Little is known about how the relative balance of these drivers of community assembly changes along environmental gradients, especially man‐made environmental gradients asso...
Tropical landscapes are changing rapidly due to changes in land use and land management. Being able to predict and monitor land use change impacts on species for conservation or food security concerns requires the use of habitat quality metrics, that are consistent, can be mapped using above - ground sensor data and are relevant for species perform...
Tropical landscapes are changing rapidly due to changes in land use and land management. Being able to predict and monitor land use change impacts on species for conservation or food security concerns requires the use of habitat quality metrics, that are consistent, can be mapped using above - ground sensor data and are relevant for species perform...
There has been an increasing interest in fodder trees and their potential to help the rural poor. However, few studies have addressed the ecological impacts of fodder tree harvesting. We investigated the species harvested and the techniques used, and the effects of fodder harvesting on (1) species’ populations and (2) forest carbon stocks in three...
Borneo contains some of the world's most biodiverse and carbon-dense tropical forest, but this 750 000 km2 island has lost 62 % of its old-growth forests within the last 40 years. Efforts to protect and restore the remaining forests of Borneo hinge on recognizing the ecosystem services they provide, including their ability to store and sequester ca...
Borneo contains some of the world’s most biodiverse and carbon dense tropical forest, but this 750 000-km2 island has lost 62 % of its old-growth forests within the last 40 years. Efforts to protect and restore the remaining forests of Borneo hinge on recognising the ecosystem services they provide, including their ability to store and sequester ca...
Tropical montane forests are amongst the most threatened ecosystems by climate change. However, little is known about climatic changes already observed in these montane areas in Africa, or the adaptation strategies used by pastoralist communities. This article, focused on three mountains in northern Kenya, aims to fill these knowledge gaps. Focus-g...
Background
Canopy structure, defined by leaf area index (LAI), fractional vegetation cover (FCover) and fraction of absorbed photosynthetically active radiation (fAPAR), regulates a wide range of forest functions and ecosystem services. Spatially consistent field-measurements of canopy structure are however lacking, particularly for the tropics. Me...
Changes in structure and functioning of tree communities in response to forest fragmentation may alter tropical forest’s capacity to store carbon and regulate climate. However, evidence for indirect effects of forest fragmentation on above – and belowground carbon pools through changes in forest biodiversity is scarce. Here we focus on understandin...
Canopy structure, defined by leaf area index (LAI), fractional vegetation cover (FCover) and fraction of absorbed photosynthetically active radiation (fAPAR), regulates a wide range of forest functions and ecosystem services. Spatially consistent field-measurements of canopy structure are however lacking, particularly for the tropics. Here, we intr...
Carbon‐based policies provide powerful opportunities to unite tropical forest conservation with climate change mitigation. However, their effectiveness in delivering biodiversity co‐benefits is dependent on high levels of biodiversity being found in high carbon areas. Previous studies have focussed solely on the co‐benefits associated with Reducing...
Forest edges influence more than half of the world's forests and contribute to worldwide declines in biodiversity and ecosystem functions. However, predicting these declines is challenging in heterogeneous fragmented landscapes. Here we assembled a global dataset on species responses to fragmentation and developed a statistical approach for quantif...
South East Asia region is a triple hotspot of carbon, biodiversity, and forest degradation. The latter is leading to heterogeneous forest landscapes with predominant and varying intensity of human modification. Optical Earth observation data offers the most feasible and accessible means of mapping and monitoring the forest cover heterogeneity in th...
Recent work in the tropics has advanced our understanding of the local impacts of land-use change on species richness. However, we still have a limited ability to make predictions about species abundances, especially in heterogeneous landscapes. Species abundances directly affect the functioning of an ecosystem and its conservation value. We applie...
Figure S1. Relationship between catchment forest quality PC1 scores and riparian forest quality PC1 scores for each of the sixteen stream sites
Table S1. Details of how streams will be affected by proposed future logging at the SAFE Project
Table S2. Loading scores showing how original forest quality variables correspond to the principal componen...
Borneo contains some of the world's most biodiverse and carbon dense tropical forest, but this 750,000-km2 island has lost 62% of its old-growth forests within the last 40 years. Efforts to protect and restore the remaining forests of Borneo hinge on recognising the ecosystem services they provide, including their ability to store and sequester car...
Freshwaters provide valuable habitat and important ecosystem services, but are threatened worldwide by habitat loss and degradation. In Southeast Asia, rainforest streams are particularly threatened by logging and conversion to oil palm, but we lack information on the impacts of this on freshwater environmental conditions, and the relative importan...
Fragmentation and habitat loss contribute considerably to global declines of amphibians and reptiles. However, few studies focus on forest edges, created during the fragmentation process, as proximate drivers of the local demographic structure of populations. Here, we use abundance data of amphibians and reptiles to study their responses to forest...
Fragmentation and habitat loss contribute considerably to global declines of amphibians and reptiles. However, few studies focus on forest edges, created during the fragmentation process, as proximate drivers of the local demographic structure of populations. Here, we use abundance data of amphibians and reptiles to study their responses to forest...
South East Asia has the highest rate of lowland forest loss of any tropical region, with logging and deforestation for conversion to plantation agriculture being flagged as the most urgent threats. Detecting and mapping logging impacts on forest structure is a primary conservation concern, as these impacts feed through to changes in biodiversity an...
Freshwaters provide valuable habitat and important ecosystem services, but are threatened worldwide by habitat loss and degradation. In Southeast Asia, rainforest streams are particularly threatened by logging and conversion to oil palm, but we lack information on the impacts of this on freshwater environmental conditions, and the relative importan...
We have limited understanding of how tropical canopy foliage varies along environmental gradients, and how this may in turn affect forest processes and functions. Here, we analyse the relationships between canopy leaf area index (LAI) and above ground herbaceous biomass (AGB H) along environmental gradients in a moist forest and miombo woodland in...
Coffee production is one of the main economic activities in Ethiopia, representing about 40% of the country’s economy. Coffee is particularly important in the Ethiopian highlands, where appropriate climate allows higher productivity and quality. The Ethiopian highlands also host an outstanding biodiversity, being considered one of the world’s most...
Invertebrates are dominant species in primary tropical rainforests, where their abundance and diversity contributes to the functioning and resilience of these globally important ecosystems. However, more than one-third of tropical forests have been logged, with dramatic impacts on rainforest biodiversity that may disrupt key ecosystem processes. We...
Despite a large increase in the area of selectively logged tropical forest worldwide, the carbon stored in deadwood across a tropical forest degradation gradient at the landscape scale remains poorly documented. Many carbon stock studies have either focused exclusively on live standing biomass or have been carried out in primary forests that are un...
Background . At least a fifth of tropical forests have been logged in the recent past. This practice is an important source of timber but there are concerns about its long-sustainability and impacts on biodiversity and carbon storage. However, there is wide variation in the impacts of logging, making generalisation, and thus policy implementation,...
Background . At least a fifth of tropical forests have been logged in the recent past. This practice is an important source of timber but there are concerns about its long-sustainability and impacts on biodiversity and carbon storage. However, there is wide variation in the impacts of logging, making generalisation, and thus policy implementation,...
Land use change is a major threat to biodiversity. One mechanism by which land use change influences biodiversity and ecological processes is through changes in the local climate. Here, the relationships between leaf area index and five climate variables – air temperature, relative humidity, vapour pressure deficit, specific humidity and soil tempe...
Anthropogenic global change compromises forest resilience, with profound impacts to ecosystem functions and services. This synthesis paper reflects on the current understanding of forest resilience and potential tipping points under environmental change and explores challenges to assessing responses using experiments, observations and models.
Fores...
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PHOTOS: (DOGS) ROGER DE LA HARPE/WWW.AFRICAIMAGERY.COM; (ELEPHANTS) LAUREN EVANS/WWW.GEOG.CAM.AC.UK/PEOPLE/L.EVANS AND WWW.SPACEFORGIANTS.ORG
Human-driven habitat fragmentation reduces global biodiversity and ecosystem functioning ([ 1 ][2]). R. Woodroffe et al. (“To fence or
Habitat fragmentation studies have produced complex results that are challenging to synthesize. Inconsistencies among studies may result from variation in the choice of landscape metrics and response variables, which is often compounded by a lack of key statistical or methodological information. Collating primary datasets on biodiversity responses...
The recent Global Inventory Modeling and Mapping Studies (GIMMS) LAI3g product provides a 30-year global times-series of remotely sensed leaf area index (LAI), an essential variable in models of ecosystem process and productivity. In this study, we use a new dataset of field-based LAITrue to indirectly validate the GIMMS LAI3g product, LAIavhrr, in...
Carbon-based forest conservation requires the establishment of ‘reference emission levels’ against which to measure a country or region’s progress in reducing their carbon emissions. In East Africa, landscape-scale estimates of carbon fluxes are uncertain and factors such as deforestation poorly resolved due to a lack of data. In this study, trends...
Creel et al. argue against the conservation effectiveness of fencing based on a population measure that ignores the importance of top predators to ecosystem processes. Their statistical analyses consider, first, only a subset of fenced reserves and, second, an incomplete examination of 'costs per lion.' Our original conclusions remain unaltered.
Conservationists often advocate for landscape approaches to wildlife management while others argue for physical separation between protected species and human communities, but direct empirical comparisons of these alternatives are scarce. We relate African lion population densities and population trends to contrasting management practices across 42...
In East Africa, human population growth and demands for natural resources cause forest loss contributing to increased carbon emissions and reduced biodiversity. Protected Areas (PAs) are intended to conserve habitats and species. Variability in PA effectiveness and 'leakage' (here defined as displacement of deforestation) may lead to different tren...
Information on management of eight randomly selected effective protected areas in East Africa.
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Comparison of forest loss within PA and within their buffer zones to country-specific background forest loss (BFL).
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