Olivier Honnay

KU Leuven | ku leuven · Department of Biology

In tropical regions, the extent of agricultural land is rapidly increasing at the expense of natural forest with associated losses of biodiversity and ecosystem services. Agroforestry has long been proposed as a more sustainable agricultural system, conserving biodiversity and ecosystem services, while providing significant local livelihood. In thi...

Species diversity is commonly hypothesized to result from trade-offs for different limiting resources, providing separate niches for coexisting species. As soil nutrients occur in multiple chemical forms, plant differences in acquisition of the same element derived from different compounds may represent unique niche dimensions. Because plant produc...

Despite the ecological significance of ericoid mycorrhizal fungi, little is known about the abiotic and biotic factors driving their diversity and community composition. To determine the relative importance of abiotic and biotic filtering in structuring ericoid mycorrhizal fungal communities, we established 156 sampling plots in two highly contrast...

Understanding how biological and environmental factors interactively shape the global distribution of plant and animal genetic diversity is fundamental to biodiversity conservation. Genetic diversity measured in local populations (GD P ) is correspondingly assumed representative for population fitness and eco-evolutionary dynamics. For 8356 populat...

Climate change and the resulting increased drought frequencies pose considerable threats to forest herb populations, particularly where additional environmental challenges jeopardize responses to selection. Specifically, habitat fragmentation may hamper climate adaptation by altering the distribution of adaptive genetic variation and may also induc...

Background and aims Plant breeders are increasingly turning to crop wild relatives (CWRs) to ensure global food security amidst a rapidly changing environment. However, CWR populations are confronted with various human-induced threats, including hybridisation with their nearby cultivated crops, posing a significant threat to the wild gene pool. Her...

Although coffee leaf rust (CLR), caused by Hemileia vastatrix, poses an increasing threat to coffee production in Ethiopia, little is known regarding its genetic diversity and structure and how these are affected by coffee management. Here, we used genetic fingerprinting based on sequence-related amplified polymorphism (SRAP) markers to genotype H....

Cultivation of Robusta coffee is likely to gain importance because of its high disease resistance and climate envelope. Robusta coffee genetic resources conserved in field genebanks can play an important role to further improve its cupping quality and other agronomic traits, but such Coffea canephora collections are limited and still poorly charact...

The current rise in the prevalence of allergies to aeroallergens is incompletely understood and attributed to interactions with environmental changes and lifestyle changes. Environmental nitrogen pollution might be a potential driver of this increasing prevalence. While the ecological impact of excessive nitrogen pollution has been widely studied a...

Recent insect pollinator declines, mainly due to the expansion and intensification of agricultural land use, are jeopardizing ecosystem service provisioning in agroecosystems. Organic farming has been suggested as a biodiversity-friendly alternative to conventional farming, but additional insights evaluating its effectiveness in perennial cropping...

Climate change and the resulting increased drought frequencies pose considerable threats to forest herb populations, particularly where additional environmental challenges jeopardize responses to selection. Specifically, habitat fragmentation may impede climate adaptation through its impact on the distribution of adaptive genetic variation, and cau...

Questions: Woody plant encroachment is known to adversely affect the biodiversity and functioning of savannah ecosystems, yet removal strategies have been shown to have variable success. Here we evaluated the effectiveness of three woody removal methods or treatments for controlling the leguminous thorny shrub Dichrostachys cinerea, and assessed pl...

Ancient semi-natural grasslands in Europe are important for ecosystem service (ES) provision. Often, the surrounding matrix contains 'Grassland Green Infrastructure' (GGI) that contain grassland species which have the potential to supplement grassland ES provision across the landscape. Here we investigate the potential for GGI to deliver a set of c...

Degradation and regeneration of tropical forests can strongly affect gene flow in understorey species, resulting in genetic erosion and changes in genetic structure. Yet, these processes remain poorly studied in tropical Africa. Coffea canephora is an economically important species, found in the understorey of tropical rainforests of Central and We...

Food security and nutrition security raise multiple questions at both the local and global levels. Experts have formulated three major challenges for the 21st century in this regard: the depletion of natural materials, the loss of environmental quality, and the assurance or guarantee of food supplies. Will we be able to produce enough food for an e...

Habitat loss is threatening natural communities worldwide. Small and isolated populations suffer from inbreeding and genetic drift, which jeopardize their long-term survival and adaptive capacities. However, the consequences of habitat loss for reciprocal coevolutionary interactions remain poorly studied. In this study, we investigated the effects...

Elevated levels of inbreeding increase the risk of inbreeding depression and extinction, yet many inbred species are widespread, suggesting that inbreeding has little impact on evolutionary potential. Here, we explore the potential for transposable elements (TEs) to maintain genetic variation in functional genomic regions under extreme inbreeding....

Ethiopian Arabica coffee is produced in different agroforestry systems which differ in forest management intensity. In forest coffee systems (FC), coffee shrubs grow naturally in the understory of Afromontane forests with little human intervention, whereas in semi-forest coffee systems (SFC) thinning of the canopy and removal of the understory is a...

Biological pest control, relying on naturally occurring predator–prey dynamics, is considered a key element to achieve more sustainable farming systems. However, the combined effects of local management and landscape factors on communities of natural enemies as well as the cascading effects on pest infestations are rarely addressed, especially in p...

Degradation and regeneration of tropical forests can strongly affect gene flow in understorey species, resulting in genetic erosion and changes in genetic structure. Yet, these processes remain poorly studied in tropical Africa. Coffea canephora is an economically important species, found in the understorey of tropical rainforests of Central and We...

Climate change is increasingly impacting temperate forest ecosystems and many forest herbs might be unable to track the changing climate due to dispersal limitation. Forest herbs with a low adaptive capacity may therefore benefit from conservation strategies that mitigate dispersal limitation and evolutionary constraints, such as assisted migration...

Species may benefit from green infrastructure, i.e. the network of natural and anthro-pogenic habitat remnants in human-dominated landscapes, if it helps isolated populations in remaining habitat patches to be functionally connected. The importance of green infrastructure is therefore increasingly emphasized in conservation policy to counter biodiv...

Despite their key role in biodiversity conservation, forests in the Congo Basin are increasingly threatened by human activities, but it remains challenging to assess the impact of forest deg- radation under a more or less intact canopy. Likewise, forest recovery following agricultural abandonment remains poorly understood in the Congo Basin. Here,...

Aims In low-input agricultural systems, arbuscular mycorrhizal fungi (AMF) play a role in plant nutrition, protection and water use. Evaluating how agricultural practices affect the composition of AMF communities is therefore an important step towards sustainable intensification. We characterized the AMF communities in enset (Ensete ventricosum) ro...

Epigenetic inheritance can drive adaptive evolution independently of DNA sequence variation. However, to what extent epigenetic variation represents an autonomous evolutionary force remains largely elusive. Through gene ontology and comparative analyses of genomic and epigenomic variation of wild strawberry plants raised in distinct drought setting...

Climate change is increasingly impacting temperate forest ecosystems and many forest herbs might be unable to track the changing climate due to dispersal limitations. Forest herbs with a low adaptive capacity are prone to climate change effects and may benefit from conservation strategies mitigating dispersal limitations and evolutionary constraint...

Conventional wisdom states that genetic variation reduces disease levels in plant populations. Nevertheless, crop species have been subject to a gradual loss of genetic variation through selection for specific traits during breeding, thereby increasing their vulnerability to biotic stresses such as pathogens. We explored how genetic variation in Ar...

Tropical moist evergreen forests provide key ecosystem services for human well‐being. However, due to human pressure, Afromontane forests have lost much of their natural species composition and structure. In this study, vegetation surveys were carried out with the aim of investigating woody species composition and structure and their drivers of deg...

Background Attempts to restore degraded highlands by tree planting are common in East Africa. However, up till now, little attention has been given to effects of tree species choice on litter decomposition and nutrient recycling. Method In this study, three indigenous and two exotic tree species were selected for a litter decomposition study. The...

Conversion of natural ecosystems into agricultural land may strongly affect the soil microbiome and the functioning of the soil ecosystem. Alternative farming systems, such as organic farming, have therefore been advocated to reduce this impact, yet the outcomes of different agricultural management regimes often remain ambiguous and their evaluatio...

Growing concerns about the negative environmental impacts of agriculture have resulted in the increasing adoption of farming systems that try to reconcile crop production with environmental sustainability, such as organic farming. As organic farming refrains from using synthetic inputs, it heavenly reli es on maintaining soil health. However, it is...

Cassava, forming starch-rich, tuberous roots, is an important staple crop in smallholder farming systems in sub-Saharan Africa. Its relatively good tolerance to drought and nutrient-poor soils may be partly attributed to the crop’s association with arbuscular mycorrhiza fungi (AMF). Yet insights into AMF-community composition and richness of cassav...

Ons voedselsysteem, en meer in het bijzonder de manier waarop we aan landbouw doen, legt momenteel een onhoudbare druk op milieukwaliteit, biodiversiteit en klimaat. In deze bijdrage formuleren de auteurs eerst een reeks bedenkingen bij een eerder in Natuurfocus verschenen artikel waarin als oplossing voor dit probleem de agro-ecologische landbouw...

Background: Attempts to restore degraded highlands by tree planting are common in East Africa. However, up till now, little attention has been given to effects of tree species choice on litter decomposition and nutrient recycling. Method: In this study, three indigenous and two exotic tree species were selected for a litter decomposition study. The...

Background: Ecosystem restoration is as a critical tool to counteract the decline of biodiversity and recover vital ecosystem services. Restoration efforts, however, often fall short of meeting their goals. Although functionally important levels of biodiversity can significantly contribute to the outcome of ecosystem restoration, they are often ov...

We tested whether roots from indigenous wild enset in Southern Ethiopia harboured a more diverse and different AMF community compared to cultivated enset. Illumina MiSeq amplicon sequencing showed that AMF communities in both cultivated and wild enset were dominated by Glomeraceae which accounted for 64% of the 145 OTUs recorded. The majority of ra...

Despite their key role in biodiversity conservation, forests of the Congo Basin are increasingly threatened by human activities. Whereas deforestation is very conspicuous, it remains challenging to monitor the impact of forest degradation under a more or less intact canopy. Likewise, the outcomes of forest regeneration following agricultural abando...

Interspecific hybridization events have played a major role in plant speciation, yet, the evolutionary origin of hybrid species often remains enigmatic. Here, we inferred the evolutionary origin of the allotetraploid species Coffea arabica, which is widely cultivated for Arabica coffee production. We estimated genetic distances between C. arabica a...

Drastic loss in the area and quality of natural and semi‐natural habitats over the last hundred years has placed biodiversity and related ecosystem functions under substantial threat. Restoration of degraded ecosystems is among the main solutions to counteract this trend. However, past restoration efforts have not always led to the anticipated halt...

Leaf mass per area (LMA), leaf dry matter content (LDMC) and leaf water content/ equivalent water thickness (EWT) are commonly used functional plant traits in ecology. Whereas spectroscopy has recently proven to be a powerful tool to collect such functional trait information across large scales, it remains unclear whether these reflectance-based tr...

Background Ecosystem restoration is as a critical tool to counteract the decline of biodiversity and recover vital ecosystem services. Restoration efforts, however, often fall short of meeting their goals. Although functionally important levels of biodiversity can significantly contribute to the outcome of ecosystem restoration, they are often over...

Aim Forest herbs might be unable to track shifts in habitat suitability due to rapid climate change and habitat fragmentation. In this study, we quantified the role of dispersal limitation and the potential mitigating effect of large-scale reforestation on the redistribution of the herbaceous forest plant species Primula elatior under climate chang...

ContextHabitat fragmentation and land use intensification are major threats to biodiversity worldwide, affecting both species (SD) and genetic (GD) diversity. It remains unclear whether SD and GD respond to the same components of landscape changes and to what extent they correlate in fragmented systems.Objectives We explore the role of current and...

Aims The aim of the study was to explore whether the encroachment of an East-African savannah ecosystem by the invasive shrub Dichrostachys cinerea L. Wight & Arn has resulted in changes in the Arbuscular Mycorrhizal Fungus (AMF) communities which are associated with roots of the extant herbaceous plant communities. We hypothesized that this could...

Arbuscular mycorrhizal fungi (AMF) are ubiquitous in agroecosystems, but their role in mediating agricultural yield remains contested. Field experiments testing effects of realistic agronomic practices of intensification on AM fungus composition and yields are scarce, especially in the low-input systems of sub-Saharan Africa. A large, full-factoria...

Semi-natural grasslands harbour many of Europe's species of conservation interest. Although larger grasslands are the focus of most conservation activity, many grassland fragments are scattered across landscapes –in small patches or along linear elements– which can form Grassland Green Infrastructure (GGI). GGI has the potential to enhance landscap...

AimsArbuscular Mycorrhizal Fungi (AMF) are ubiquitous soil microorganisms playing a vital role in the functioning of agricultural ecosystems. Although AMF are generally considered to have a low host specificity, it has been suggested that modern plant breeding has selected crop genotypes that are more selectively associated with AMF, possibly resul...

Currently, one of the most important challenges is to provide sufficient and affordable food and energy for a fast-growing world population, alongside preserving natural habitats and maintaining biodiversity. About 35% of the global food production depends on animals for pollination. In recent years, an alarming worldwide decline in pollinators has...

Adaptive evolution is generally thought to be the result of natural selection predominantly acting upon pre-existing DNA sequence polymorphisms through gene-environment interactions. Epigenetic inheritance is, however, recently considered an additional molecular force driving adaptive evolution independent of DNA sequence variation. Through compara...

Alien plant species invasiveness and impact on diversity (i.e. species richness and composition) can be driven by the altered competitive interactions experienced by the invader in its invaded range compared to its native range. Trait‐based competition effects on invasiveness can be mediated through size‐asymmetric competition, i.e. a trait suit of...

Context Functional connectivity is vital for plant species dispersal, but little is known about how habitat loss and the presence of green infrastructure interact to affect both functional and structural connectivity, and the impacts of each on species groups. Objectives We investigate how changes in the spatial configuration of species-rich grass...

‘Conference’ (Pyrus communis L.) is a self-incompatible cultivar, although it can also set fruit parthenocarpically. Stimulating parthenocarpy through gibberellin (GA) applications increases the fruit set, but it may also negatively affect the fruit size and shape. The aim of this study was to investigate the effects of a bumblebee (BB) amendment i...

Invasieve uitheemse soorten worden gezien als een van de grote bedreigingen voor onze biodiversiteit. Aan de Belgische kust blijkt ondertussen 60% van de flora uitheems te zijn. Een aantal van deze soorten beginnen zich invasief te gedragen. Een van de meest problematische invasieve uitheemse soorten in de duinen is Rimpelroos Rosa rugosa, waarvan...

Worldwide, invasive alien plant species (IAS) threaten the biodiversity and the functioning of ecosystems. Most invasion research so far has focused on the properties underlying species invasiveness and community invasibility, yet IAS impact and the underlying causal pathways remain largely unknown. Here we dealt with this knowledge gap by extendin...

Our ability to measure plant characteristics across space and time is crucial for understanding and tracking the diversity and functioning of ecosystems. Ecological approaches to synthesize these characteristics have evolved from allocating species to predefined conventional plant functional types (cPFTs) to describing vegetation through delineatin...

Epigenetic change is considered relatively unstable and short‐lived, raising questions of its contribution to long‐term adaptive potential. However, epigenetic modifications can accumulate in the presence of environmental stress, resulting in beneficial epigenetic memories where environments are challenging. Diverging epigenetic memories have been...

Questions: Woody encroachment is increasingly affecting biodiversity and ecosystem functioning of savannah ecosystems worldwide, yet the direction and magnitude of these impacts often seem context‐dependent. Here, we investigated the potential of a trait‐based framework to understand the effect of the encroaching shrub Dichrostachys cinerea on plan...

Soil salinization due to sea level rise and groundwater irrigation has become an important agronomic problem in many parts of the world. Symbiosis between crop species and arbuscular mycorrhizal fungi (AMF) may alleviate salt stress-induced detrimental effects on crop growth and yield, for example, through helping the host plant to selectively abso...

De bomen in de stad vormen samen het stadsbos en spelen een cruciale rol voor de leefbaarheid van de stad (Straatsburg). Bomen leveren onmisbare diensten aan de stad, maar ze worden vaak geconfronteerd met een moeilijke en stres-serende groeiomgeving. In de natuur dragen ectomycorrhizale bodemschimmels bij aan de groei en gezondheid van bomen. Toch...