Biology subjects

Grytnes, J.-A.

Publications and source records attributed to Grytnes, J.-A..

3 recordsLinked to original sources

bioRxiv2026

Addressing Data Fragmentation in Biodiversity: A Workflow for integrated Species Distribution Models

AimA comprehensive understanding of the spatial distribution of biodiversity is hindered by fragmented datasets, sampling biases, and inconsistent observation protocols. Here, we present a workflow that integrates disparate datasets to produce large scale maps of biodiversity metrics as a basis for management-relevant information tools. We use integrated species distribution modeling (iSDM) to account for sampling biases and disparate data collection techniques, taking advantage of the vast numbers of open datasets available in data aggregators like GBIF. LocationNorway (excluding Svalbard and Jan Mayen) TaxonVascular plants MethodsThe workflow consists of four main steps: data acquisition, data integration, integrated species distribution modelling (iSDM), and the production of derived outputs. Input data include structured surveys, opportunistic observations, and environmental covariates. These are standardised and integrated into a point-processed based iSDM framework to produce species richness maps, associated uncertainties, and sampling effort maps. The outputs are further processed to identify biodiversity hotspots or to summarise species-environment relationships. The workflow used vascular plant data from Norway, combining occurrence-only and presence-absence datasets with environmental covariates. Outputs were generated at a spatial resolution of 500 x 500 meters, balancing accuracy, computational feasibility and relevance for management decisions. High-performance computing resources were utilized for model fitting and predictions. A subset of available data was used to validate the species richness maps. ResultsWe produced detailed maps of species richness, uncertainties and sampling intensity across Norways heterogeneous landscape, incorporating 1218 species in our final results. The species richness patterns highlight patterns consistent with previous mapping efforts. Validation showed an increase in model accuracy when compared to models which did not use an iSDM framework. The workflow highlights limitations in the infrastructure of the currently openly accessible data, particularly the need for more structured presence-absence datasets and standardized metadata. Main conclusionsThis study underscores the potential of workflows that integrate disparate datasets for biodiversity modeling. To maximize accuracy and utility, future efforts should focus on improving data standardization, the publication and collection of more structured data, and fostering data-sharing collaborations. Advances in the workflow itself, including optimising modelling covariates and integrating more comprehensive spatio-temporal aspects, will also increase the relevance of the outputs. These advances will increase our ability to estimate species richness with a precision and accuracy that can reliably inform conservation and management decisions.

ecology↗

bioRxiv2024

Long-term homogenization of vascular plant and lichen communities across Fennoscandian heathlands and tundra is connected to the expansion of an allelopathic dwarf shrub

Boreal and tundra plant communities are expected to change in biodiversity due to increasing global change pressures such as climate warming. One long-term scenario is increasing compositional similarity, i.e., biotic homogenization, which has been relatively little studied in high-latitude plant communities. Here, we study how the composition and diversity of heathland and tundra plant communities have changed in northern Fennoscandia over several decades. In 2013-2023, we resurveyed 275 historic vegetation plots, originally surveyed in 1964-1975, with percentage covers for vascular plant, bryophyte and lichen species. We analyzed temporal changes in community composition and diversity across the study area and in different habitat types, biogeographic zones, and along the continentality-humidity gradient. We found a strong trend across the study area, with plant communities becoming more similar in composition over the decades. The observed homogenization was associated with compositional changes in vascular plant and lichen communities, and in particular with the encroachment of the evergreen dwarf shrub Empetrum nigrum. In comparison to vascular plants and lichens, the diversity of bryophytes generally remained more stable over time. Our findings suggest that Fennoscandian heathland and tundra vegetation is transforming towards a more homogenous evergreen dwarf shrub dominated system, which may threaten ecosystem multifunctionality. Our results highlight the importance of exploring biodiversity among different metrics and growth forms to understand the overall changes in heathland and tundra biodiversity.

ecology↗

bioRxiv2020

Trait-based responses to forestry and grazing modify long-term changes in biodiversity hot-spots of boreal forests

AimLand use is the foremost cause of global biodiversity decline, but species do not respond equally to land-use practices. Instead, it is suggested that responses vary with species traits, but long-term data on the trait-mediated effects of land-use on communities is scarce. Here we study how forest understory communities have been affected by two land-use practices during 4-5 decades, and whether changes in plant diversity are related to changes in functional composition. LocationFinland Time period1968-2019 Major taxa studiedVascular plants MethodsWe resurveyed 245 vegetation plots in boreal herb-rich forest understories, and used hierarchical Bayesian linear models to relate changes in diversity, species composition, average plant size, and leaf economic traits to reindeer abundance, forest management intensity, and changes in climate, canopy cover and composition. ResultsIntensively managed forests decreased in species richness and had increased turnover, but management did not affect functional composition. Increased reindeer densities corresponded with increased leaf dry matter content, evenness and diversity, and decreased height and specific leaf area. Successional development in the canopy was associated with increased specific leaf area and decreased leaf dry matter content and height in the understory over the study period. Effects of reindeer abundance and canopy density on diversity were partially mediated by vegetation height, which had a negative relationship with evenness. Observed changes in climate had no discernible effect on any variable. Main conclusionsFunctional traits are useful in connecting vegetation changes to the mechanisms that drive them, and provide unique information compared to turnover and diversity metrics. These trait-dependent selection effects could inform whether species benefit or suffer from land use changes and explain observed biodiversity changes under global change.

ecology↗