Landscape Heterogeneity Research Articles

The modernisation of newborn screening as a pan-European challenge – An international delphi study

Newborn screening is a public health measure to diagnose rare diseases at birth, thereby minimising negative effects of late treatment. Genomic technologies promise an unprecedented expansion of screened diseases at low cost and with transformative potential for newborn screening programmes. However, barriers to the public funding of genomic newborn screening are poorly understood, particularly in light of the heterogenous European newborn screening landscape. This study therefore aims to understand whether international newborn screening experts share a common understanding of the barriers to fund genomic newborn screening. For this purpose, we convened 21 European newborn screening experts across a range of professions and national backgrounds in a Delphi study. Stable consensus, determined via the Wilcoxon matched-pairs signed-ranks test, was found via three consecutive survey rounds for all presented barriers. Experts generally judged the scenario of genomic newborn screening being available to every newborn in seven years to be unlikely, identifying treatability and the absence of counselling and a skilled workforce as the most significant barriers to public funding. We identify value re-definition for rare disease treatments, centralisation of genomic expertise, and international research consortia as avenues for pan-European actions which build on the consensus achieved by our Delphi panel.

Mapping the heterogeneous removal landscape of wastewater virome in effluents of different advanced wastewater treatment systems of swine farm

In advanced wastewater treatment plants on pig farms, meticulous design aims to eliminate intrinsic pollutants such as organic matter, heavy metals, and biological contaminants. In our field survey across Southern China, a notable disparity in wastewater treatment procedures among various farming facilities lies in the utilization of terminal chemical oxidation post-sedimentation tank. However, recent focus in wastewater surveillance has predominantly centered on antibiotic resistance genes, leaving the efficacy of virus removal in different effluent systems largely unexplored. To profile virus composition at the effluent, assess the virus elimination efficiency of chemical oxidation at the effluent end, and the potential environmental driver of virus abundance, we deployed a meta-transcriptomics approach to first determine the total virome in effluent specimens of terminal clean water tank system (CWT) and terminal chemical oxidation system (TCO) in Southern China pig farms, respectively. From these data, 172 viruses were identified, with a median reads per million (RPM) of 27,789 in CWT and 19,982 in TCO. Through the integration of analyses encompassing the co-occurrence patterns within viral communities, the ecology of viral diversity, and a comparative assessment of average variation degrees, we have empirically demonstrated that the procedure of TCO may perturb viral communities and diminish their abundance, particularly impacting RNA viral communities. However, despite the diminished abundance, pathogenic viruses such as PEDV and PRRSV persisted in the effluent following chemical deoxidation at a moderate RPM value, indicating a substantial in situ presence at effluent. Our environmental driver modeling, employing GLM and mantel tests, substantiated the intricate nature of virus community variation within the effluent, influenced heterogeneously by diverse factors. Notably, pond temperature emerged as the foremost determinant, while fishing farming exhibited a positive correlation with virus diversity (p < 0.05). This revelation of the cryptic persistence of virus communities in wastewater effluent expands our understanding of the varied responses of different virus categories to oxidation. Such insights transcend mere virus characterization, offering valuable implications for enhancing biosafety measures in farming practices and informing wastewater-based epidemiological surveillance.

Patch shape, connectivity and functional groups moderate the responses of bird diversity to agricultural diversification — A meta-analysis

Agricultural expansion and intensification pose significant threats to global biodiversity. However, the conservation of agricultural biodiversity is essential for harmonizing agricultural production with ecological sustainability. Agricultural diversification can mitigate the negative impacts of agriculture on ecosystem functioning and biodiversity. Characteristics of the broader landscape may also play an important moderating role in diversified agricultural landscapes, but are not fully solved. To bridge this gap, we conducted a meta-analysis of peer-reviewed studies to compare bird abundance and species richness in diversified agricultural landscapes compared to those in simplified farmlands and natural landscapes. We also explored the moderating role of species functional groups and 11 metrics of landscape composition, configuration and heterogeneity. We found a generally positive effect of perimeter-to-area ratio of farmland patches, connectivity within farmland patches, and connectivity within patches of natural and semi-natural habitats on bird abundance and species richness. Responses to other landscape metrics were less consistent. For pollinators, the abundance was higher in diversified agricultural landscapes compared to control groups, and particularly when compared to natural landscapes. For natural enemies, the species richness was significantly lower in diversified agricultural landscapes than in natural landscapes, while their abundance was not. The overall abundance and species richness of granivores and frugivores in diversified agricultural landscapes were comparable to those in control landscapes. These results indicated landscape type of control groups, species functional groups, and their interactions had consistent impacts on the responses of bird diversity. We found a vital role of farmland patch shape and connectivity within farmland and habitat patches for bird conservation in diversified agricultural landscapes, which has been rarely reported in previous studies. These insights underscore the need for policymakers and managers to develop farmland management and planning strategies at multiple scales to fulfill growing human demands while achieving biodiversity conservation objectives.

Somatic mutations in 3929 HPV positive cervical cells associated with infection outcome and HPV type

Invasive cervical cancers (ICC), caused by HPV infections, have a heterogeneous molecular landscape. We investigate the detection, timing, and HPV type specificity of somatic mutations in 3929 HPV-positive exfoliated cervical cell samples from individuals undergoing cervical screening in the U.S. using deep targeted sequencing in ICC cases, precancers, and HPV-positive controls. We discover a subset of hotspot mutations rare in controls (2.6%) but significantly more prevalent in precancers, particularly glandular precancer lesions (10.2%), and cancers (25.7%), supporting their involvement in ICC carcinogenesis. Hotspot mutations differ by HPV type, and HPV18/45-positive ICC are more likely to have multiple hotspot mutations compared to HPV16-positive ICC. The proportion of cells containing hotspot mutations is higher (i.e., higher variant allele fraction) in ICC and mutations are detectable up to 6 years prior to cancer diagnosis. Our findings demonstrate the feasibility of using exfoliated cervical cells for detection of somatic mutations as potential diagnostic biomarkers.

Evolution of the correlated genomic variation landscape across a divergence continuum in the genus Castanopsis.

The heterogeneous landscape of genomic variation has been well documented in population genomic studies. However, disentangling the intricate interplay of evolutionary forces influencing the genetic variation landscape over time remains challenging. In this study, we assembled a chromosome-level genome for Castanopsis eyrei and sequenced the whole genomes of 276 individuals from 12 Castanopsis species, spanning a broad divergence continuum. We found highly correlated genomic variation landscapes across these species. Furthermore, variations in genetic diversity and differentiation along the genome were strongly associated with recombination rates and gene density. These results suggest that long-term linked selection and conserved genomic features have contributed to the formation of a common genomic variation landscape. By examining how correlations between population summary statistics change throughout the species divergence continuum, we determined that background selection alone does not fully explain the observed patterns of genomic variation; the effects of recurrent selective sweeps must be considered. We further revealed that extensive gene flow has significantly influenced patterns of genomic variation in Castanopsis species. The estimated admixture proportion correlated positively with recombination rate and negatively with gene density, supporting a scenario of selection against gene flow. Additionally, putative introgression regions exhibited strong signals of positive selection, an enrichment of functional genes, and reduced genetic burdens, indicating that adaptive introgression has played a role in shaping the genomes of hybridizing species. This study provides insights into how different evolutionary forces have interacted in driving the evolution of the genomic variation landscape.

Multiscale spatial analysis of two plant–insect interactions: effects of landscape, resource distribution, and other insects

ContextBiotic resource exploitation is a critical determinant of species’ distributions. However, quantifying resource exploitation patterns through space and time can be difficult, complicating their incorporation in spatial ecology studies. Therefore, understanding the local drivers of spatial patterns of resource exploitation may contribute to better large-scale species distribution models.ObjectivesWe investigated (1) how the resource exploitation patterns of two trophic interactions (plant–insect) are explained by insect behaviour, resource aggregation, and potential insect-insect interactions. We also analyzed how (2) resource patch size and (3) resource accessibility in a heterogeneous landscape affected host exploitation patterns.MethodsWe quantified nectar robbing by insects in the genus Bombus (bumblebees) and seed predation by Brachypterolus vestitus larvae (Antirrhinum beetle) on Antirrhinum majus L. (wild snapdragons) in the Pyrenees Mountains, Catalonia, Spain. We tested hypotheses about resource exploitation by integrating spatial analyses at multiple scales.ResultsBoth trophic interactions were aggregated, explained by the aggregation of their resource. At some scales, nectar robbing is more aggregated than the resource. Trophic interaction abundance is proportional to resource patch size, following the ideal free distribution model. Landscape features do not explain the locations exploited. Nectar robbing and seed predation occur together more often than expected.ConclusionsOur findings suggest that multiple biotic and ecological spatial factors may simultaneously affect resource exploitation at a local scale. These findings should be considered when developing agricultural projects, management plans and conservation policies.

The productivity-stability trade-off in global food systems.

Historically, humans have managed food systems to maximize productivity. This pursuit has drastically modified terrestrial and aquatic ecosystems globally by reducing species diversity and body size while creating very productive, yet homogenized, environments. Such changes alter the structure and function of ecosystems in ways that ultimately erode their stability. This productivity-stability trade-off has largely been ignored in discussions around global food security. Here, we synthesize empirical and theoretical literature to demonstrate the existence of the productivity-stability trade-off and argue the need for its explicit incorporation in the sustainable management of food systems. We first explore the history of human management of food systems, its impacts on average body size within and across species and food web stability. We then demonstrate how reductions in body size are symptomatic of a broader biotic homogenization and rewiring of food webs. We show how this biotic homogenization decompartmentalizes interactions among energy channels and increases energy flux within the food web in ways that threaten their stability. We end by synthesizing large-scale ecological studies to demonstrate the prevalence of the productivity-stability trade-off. We conclude that management strategies promoting landscape heterogeneity and maintenance of key food web structures are critical to sustainable food production.

Taxonomic diversity of amphibians (Amphibia, Anura) and reptiles (Reptilia, Testudines, Squamata) in a heterogeneous landscape in west-central Mexico: a checklist and notes on geographical distributions.

In Mexico, land use changes have significantly impacted the diversity of amphibians and reptiles in a negative way. In light of this, we evaluate the alpha and beta components of the taxonomic diversity of amphibians and reptiles in a heterogeneous landscape in west-central Mexico. Additionally, we provide a checklist of amphibian and reptile species recorded over nine years of observations within the studied landscape and surrounding areas. The land cover/use types with the highest species richness and alpha taxonomic diversity differed between amphibians and reptiles. Overall beta taxonomic diversity was high for both groups, but slightly higher in reptiles. This taxonomic differentiation mainly corresponded to a difference in the turnover component and was greater in pristine habitats compared to disturbed ones. The checklist records 20 species of amphibians (ten of which are endemic) and 48 of reptiles (30 endemics). Additionally, the study expands the known geographical distribution range of one species of frog and three species of snakes. Our findings suggest that heterogeneous landscapes with diverse land cover/use types can provide essential habitats for the conservation of amphibian and reptile species.

Mesopredators have differing influences on prey habitat use and diel activity in a multipredator landscape

AbstractResource distribution, habitat structure, and predators greatly influence spatial and temporal landscape use by prey species. The “risky places” hypothesis establishes prey will proactively respond to predators' presence based on habitat cues, whereas the “risky times” hypothesis predicts prey will reactively respond by increasing vigilance in the presence of predators regardless of habitat cues. We fit a multiscale, Bayesian species interaction occupancy model with detection/non‐detection data to evaluate black‐tailed jackrabbit (Lepus californicus) and eastern cottontail rabbit (Sylvilagus floridanus) habitat use in the presence and absence of coyotes (Canis latrans), American badgers (Taxidea taxus), and swift foxes (Vulpes velox). We also evaluated how species‐specific predator presence modified temporal activity patterns of prey. Jackrabbits decreased habitat use in areas with greater forage and opted to use areas with greater visibility when coyotes or swift foxes were present. However, cottontails used habitat in open areas with greater visibility when American badgers were present and all other predators absent, suggesting dissimilar habitat‐use patterns dictated by predator‐specific risks. Both lagomorph species are nocturnal with segregated peaks of activity compared with predators, suggesting fine‐scale temporal use partitioning. Our results provide insights into predator–prey dynamics across heterogenous landscapes in a multi‐predator system.

Evidence of longitudinal differences in spring migration strategies of an Arctic-nesting goose.

During spring, migratory birds are required to optimally balance energetic costs of migration across heterogeneous landscapes and weather conditions to survive and reproduce successfully. Therefore, an individual's migratory performance may influence reproductive outcomes. Given large-scale changes in land use, climate, and potential carry-over effects, understanding how individuals migrate in relation to breeding outcomes is critical to predicting how future scenarios may affect populations. We used GPS tracking devices on 56 Greater White-fronted Geese (Anser albifrons) during four spring migrations to examine whether migration characteristics influenced breeding propensity and breeding outcome. We found a strong longitudinal difference in arrival to the breeding areas (18 days earlier), pre-nesting duration (90.9% longer), and incubation initiation dates (9 days earlier) between western- and eastern-Arctic breeding regions, with contrasting effects on breeding outcomes, but no migration characteristic strongly influenced breeding outcome. We found that breeding region influenced whether an individual likely pursued a capital or income breeding strategy. Where individuals fell along the capital-income breeding continuum was influenced by longitude, revealing geographic effects of life-history strategy among conspecifics. Factors that govern breeding outcomes likely occur primarily upon arrival to breeding areas or are related to individual quality and previous breeding outcome, and may not be directly tied to migratory decision-making across broad scales.

NUP98 oncofusions in myeloid malignancies: An update on molecular mechanisms and therapeutic opportunities.

Acute myeloid leukemia (AML) is an aggressive hematological malignancy with a heterogeneous molecular landscape. In the pediatric context, the NUP98 gene is a frequent target of chromosomal rearrangements that are linked to poor prognosis and unfavorable treatment outcomes in different AML subtypes. The translocations fuse NUP98 to a diverse array of partner genes, resulting in fusion proteins with novel functions. NUP98 fusion oncoproteins induce aberrant biomolecular condensation, abnormal gene expression programs, and re-wired protein interactions which ultimately cause alterations in the cell cycle and changes in cellular structures, all of which contribute to leukemia development. The extent of these effects is steered by the functional domains of the fusion partners and the influence of concomitant somatic mutations. In this review, we discuss the complex characteristics of NUP98 fusion proteins and potential novel therapeutic approaches for NUP98 fusion-driven AML.

Single-Cell RNA Sequencing Reveals Transcriptional Landscape of Neutrophils and Highlights the Role of TREM-1 in EAE.

Neutrophils, underestimated in multiple sclerosis (MS), are gaining increased attention for their significant functions in patients with MS and the experimental autoimmune encephalomyelitis (EAE) animal model. However, the precise role of neutrophils in cervical lymph nodes (CLNs), the primary CNS-draining lymph nodes where the autoimmune response is initiated during the progression of EAE, remains poorly understood. Applying single-cell RNA sequencing (scRNA-seq), we constructed a comprehensive immune cell atlas of CLNs during development of EAE. Through this atlas, we concentrated on and uncovered the transcriptional landscape, phenotypic and functional heterogeneity of neutrophils, and their crosstalk with immune cells within CLNs in the neuroinflammatory processes in EAE. Notably, we observed a substantial increase in the neutrophil population in EAE mice, with a particular emphasis on the significant rise within the CLNs. Neutrophils in CLNs were categorized into 3 subtypes, and we explored the specific roles and developmental trajectories of each distinct neutrophil subtype. Neutrophils were found to engage in extensive interactions with other immune cells, playing crucial roles in T-cell activation. Moreover, our findings highlighted the strong migratory ability of neutrophils to CLNs, partly regulated by triggering the receptor expressed on myeloid cells 1 (TREM-1). Inhibiting TREM1 with LR12 prevents neutrophil migration both in vivo and in vitro. In addition, in patients with MS, we confirmed an increase in peripheral neutrophils with an upregulation of TREM-1. Our research provides a comprehensive and precise single-cell atlas of CLNs in EAE, highlighting the role of neutrophils in regulating the periphery immune response. In addition, TREM-1 emerged as an essential regulator of neutrophil migration to CLNs, holding promise as a potential therapeutic target in MS.

Unravelling tectonic and lithological effects on transient landscapes in the Gulf of Corinth, Greece

AbstractLandscapes are the integrated product of external forcings (e.g. tectonics and climate) and intrinsic characteristics (e.g. bedrock erodibility). In principle, hard bedrock with low erodibility can steepen rivers in a similar way to tectonic uplift. A key challenge in geomorphic analysis is thus separating the tectonic and lithological effects on landscapes. To address this, we focus on multiple rivers that are transiently incising through contrasting lithologies in the Gulf of Corinth, Greece, where tectonic history is broadly well constrained. We first exploit topographic metrics and river long profiles to demonstrate that landscapes are responding to both tectonics and lithology. In particular, the long profiles are divided into knickpoint‐bounded segments, and at this scale, channel steepness is shown to be more sensitive to lithology than the entire catchment, possibly due to relatively uniform erosion rate at the segment scale. We then use segment‐scale steepness variations between different lithologies to constrain their relative erodibilities (Klime:Kcong.:Ksand‐silt:Kp‐con sed. = 1:2:3:4), which are further converted into actual lithology‐dependent erodibilities by modelling a well‐constrained, ca. 700 ka knickpoint in the Vouraikos catchment. The effectiveness of lithology‐dependent erodibilities is supported by the observation that if lithology‐dependent erodibilities are used to calibrate studied river long profiles in χ distance, we obtain long profile concavities that fall within the theoretical range. Finally, we use lithology‐calibrated metrics to provide new geomorphic constraints on the timing and magnitude of tectonic perturbations in these catchments. These geomorphic results are interpreted in conjunction with previous onshore and offshore studies to shed new light on fault growth and linkage history in the Gulf of Corinth. Our study therefore provides a topographic analysis‐based approach to quantify lithological effects on transient catchments, with important implications for tectonic interpretations of topographic metrics in lithologically heterogenous landscapes.

Mapping of temperate upland habitats using high-resolution satellite imagery and machine learning

Upland habitats provide vital ecological services, yet they are highly threatened by natural and anthropogenic stressors. Monitoring these vulnerable habitats is fundamental for conservation and involves determining information about their spatial locations and conditions. Remote sensing has evolved as a promising tool to map the distribution of upland habitats in space and time. However, the resolutions of most freely available satellite images (e.g., 10-m resolution for Sentinel-2) may not be sufficient for mapping relatively small features, especially in the heterogeneous landscape—in terms of habitat composition—of uplands. Moreover, the use of traditional remote sensing methods, imposing discrete boundaries between habitats, may not accurately represent upland habitats as they often occur in mosaics and merge with each other. In this context, we used high-resolution (2 m) Pleiades satellite imagery and Random Forest (RF) machine learning to map habitats at two Irish upland sites. Specifically, we investigated the impact of varying spatial resolutions on classification accuracy and proposed a complementary approach to traditional methods for mapping complex upland habitats. Results showed that the accuracy generally improved with finer spatial resolution data, with the highest accuracy values (80.34% and 79.64%) achieved for both sites using the 2-m resolution datasets. The probability maps derived from the RF-based fuzzy classification technique can represent complex mosaics and gradual transitions occurring in upland habitats. The presented approach can potentially enhance our understanding of the spatiotemporal dynamics of habitats over large areas.

Comprehensive and open model structure for the design of future energy systems with sector coupling

Energy system modeling supports the identification of the optimal technology mix to achieve decarbonization targets across multiple sectors. Especially when sector coupling is considered for future technology landscapes, the large solution space leads to a complex optimization problem in terms of computational feasibility and data requirements. The authors identify a research gap in developing an open-source model structure with consideration of the relevant future technologies of power, heat, other conversions, transport, and industry defined with a new level of detail in a sector-coupled energy world and in including detailed insights into the accompanying definition process. A strong focus is set on the transparency and reproducibility of the provided open-source structure and its flexible and consistent application to different framework families to foster the ease of applicability of this work. The paper first gives a detailed description of the model base, including an overview of the model frame definition process, the core adjustments to model sector coupling appropriately, and the measures to make the resulting problem computationally feasible. The core result of this work is the presentation of a detailed model structure to model sector coupling for a German energy system, yielding approximately 2000 processes that characterize the heterogeneous and technology-open landscape of existing and possible future technologies across relevant energy sectors. This supports energy system modelers in understanding and reproducing energy system models based on open-source data and thereby tries to accelerate the research on sector coupling and its role in the energy transition.

Testing a trapping protocol for generic surveillance of wood-boring beetles in heterogeneous landscapes

Testing a trapping protocol for generic surveillance of wood-boring beetles in heterogeneous landscapes

Analyzing the Spatial Distribution of Immune Cells in Lung Adenocarcinoma.

(1) Background: This study investigates the tumor immune microenvironment, focusing on immune cell distribution in lung adenocarcinoma. (2) Methods: We evaluated fifty cases of lung adenocarcinoma, and suitable areas for further studies were annotated on the histological slides. Two tumor cores per case were obtained, one from the tumor's center and another from its periphery, and introduced into three paraffin receptor blocks for optimized processing efficiency. The 4-micrometer-thick tissue microarray sections were stained for H&E and for CD68, CD163, CD8, CD4, and PD-L1; (3) Results: Our investigation revealed significant correlations between PD-L1 expression in tumor cells and the presence of CD163+ macrophages, between CD4+ cells and CD8+, CD68+, and CD163+ cells, and also between CD8+ T cells and CD163+ cells. Additionally, while we observed some differences in cellular components and densities between the tumor center and periphery, these differences were not statistically significant. However, distinct correlations between PD-L1 and immune cells in these regions were identified, suggesting spatial heterogeneity in the immune landscape. (4) Conclusions: These results emphasize the intricate interactions between immune cells and tumor cells in lung adenocarcinoma. Understanding patient spatial immune profile could improve patient selection for immunotherapy, ensuring that those most likely to benefit are identified.

Cisuralian plant fossils from Khenifra (Central Morocco): Palaeoenvironmental and palaeobiogeographical reconstructions

This study focuses on newly collected plant fossils from the Cisuralian successions of the Khenifra Basin in Central Morocco, revealing a diverse assemblage dominated by conifers, pteridosperms, and sphenophytes. The assemblage includes eleven taxa of vegetative and reproductive organs preserved as compressions and impressions. Two pteridosperm species taxa (Neurodontopteris auriculata, Odontopteris subcrenulata) are recorded for the first time from Central Morocco, whereas other taxa are known from the early Permian deposits of Bou Achouch and Tiddas basins. Contrary to previous interpretations, the flora is does not exhibit a mixed character, but instead exhibits a distinct Euramerican affinity, despite the absence of the widespread callipterids Autunia conferta and A. naumannii. These similarities between this flora and coeval Euramerican floras highlight the significant biogeographical connections across Pangea during the Cisuralian. The plant fossil assemblage is dominated by meso- to xerophilous species adapted to drought, with rare hygrophilous elements adapted to humid habitats, reflecting a heterogeneous landscape with various vegetation types.

Single-cell landscape of intratumoral heterogeneity and tumor microenvironment remolding in pre-nodal metastases of breast cancer

BackgroundThe metastasis of cancer cells is influenced by both their intrinsic characteristics and the tumor microenvironment (TME). However, the molecular mechanisms underlying pre-nodal metastases of breast cancer remain unclear.MethodsWe integrated a total of 216,963 cells from 54 samples across 6 single-cell datasets to profile the cellular landscape differences between primary tumors and pre-nodal metastases.ResultsWe revealed three distinct metastatic epithelial cell subtypes (Epi1, Epi2 and Epi3), which exhibited different metastatic mechanisms. Specifically, the marker gene KCNK15 of the Epi1 subtype exhibited increased gene expression along the cell differentiation trajectory and was specifically regulated by the transcription factor ASCL1. In the Epi3 subtype, we highlighted NR2F1 as a regulator targeting the marker gene MUCL1. Additionally, we found that the Epi2 and Epi3 subtypes shared some regulons, such as ZEB1 and NR2C1. Similarly, we identified specific subtypes of stromal and immune cells in the TME, and discovered that vascular cancer-associated fibroblasts might promote capillary formation through CXCL9+ macrophages in pre-nodal metastases. All three subtypes of metastatic epithelial cells were associated with poor prognosis.ConclusionsIn summary, this study dissects the intratumoral heterogeneity and remodeling of the TME in pre-nodal metastases of breast cancer, providing novel insights into the mechanisms underlying breast cancer metastasis.

Consequences of intraspecific competition for floral resources in heterogeneous landscapes for eusocial bees

Agricultural intensification is widely recognised as a primary driver of pollinator loss, but the success of land-management actions designed to remediate its impact is often mixed. Payments to farmers to increase habitat connectivity or the availability of floral and nesting resources may only result in short-term gains or even unintended consequences. The reasons may lie in changes to interaction networks or competition intensity that remain poorly understood. Models of pollination service typically implicitly assume pollinator population dynamics are regulated by nest-site availability, even though empirical evidence suggests nest-site occupancy is likely at least in part dependent on floral resource availability. To investigate the consequences of competition for floral resources in coarse-grained agricultural landscapes we extended an established model for bees combining optimal foraging and population dynamics, to include new functions for floral resource depletion and realistic colony dynamics. We find that intra-specific competition occurs late in the season forcing bees to forage underutilised sites situated further towards their foraging range limits. A lower rate of energy acquisition ultimately limits the size of the colony peak and delays its timing. Consequently, competition for floral resources can limit population size and distribution while at the same time contributing to a more stable and efficacious pollination service. Although competition was not found to be important in nest-site establishment success, the effect of a hunger gap early in the season on nest-site occupancy indirectly influences competition later in the season leading to complex outcomes.