ORCID Profile
0000-0002-8693-9304
Current Organisations
Ghent University
,
Bundesamt für Wasserwirtschaft
,
TU Wien
,
KU Leuven
,
Federal Agency for Water Management
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Publications
Edge influence on understorey plant communities depends on forest management
Publisher: Wiley
Date: 05-02-2020
DOI: 10.1111/JVS.12844
SHui, an EU-Chinese cooperative project to optimize soil and water management in agricultural areas in the XXI century
Publisher: Elsevier BV
Date: 03-2020
Evaluating structural and compositional canopy characteristics to predict the light‐demand signature of the forest understorey in mixed, semi‐natural temperate forests
Publisher: Wiley
Date: 18-10-2020
DOI: 10.1111/AVSC.12532
Sensitivity of Sentinel-1 Backscatter to Vegetation Dynamics: An Austrian Case Study
Publisher: MDPI AG
Date: 09-2018
DOI: 10.3390/RS10091396
Abstract: Crop monitoring is of great importance for e.g., yield prediction and increasing water use efficiency. The Copernicus Sentinel-1 mission operated by the European Space Agency provides the opportunity to monitor Earth’s surface using radar at high spatial and temporal resolution. Sentinel-1’s Synthetic Aperture Radar provides co- and cross-polarized backscatter, enabling the calculation of microwave indices. In this study, we assess the potential of Sentinel-1 VV and VH backscatter and their ratio VH/VV, the cross ratio (CR), to monitor crop conditions. A quantitative assessment is provided based on in situ reference data of vegetation variables for different crops under varying meteorological conditions. Vegetation Water Content (VWC), biomass, Leaf Area Index (LAI) and height are measured in situ for oilseed-rape, corn and winter cereals at different fields during two growing seasons. To quantify the sensitivity of backscatter and microwave indices to vegetation dynamics, linear and exponential models and machine learning methods have been applied to the Sentinel-1 data and in situ measurements. Using an exponential model, the CR can account for 87% and 63% of the variability in VWC for corn and winter cereals. In oilseed-rape, the coefficient of determination ( R 2 ) is lower ( R 2 = 0.34) due to the large difference in VWC between the two growing seasons and changes in vegetation structure that affect backscatter. Findings from the Random Forest analysis, which uses backscatter, microwave indices and soil moisture as input variables, show that CR is by and large the most important variable to estimate VWC. This study demonstrates, based on a quantitative analysis, the large potential of microwave indices for vegetation monitoring of VWC and phenology.
Soil properties and neighbouring forest cover affect above‐ground biomass and functional composition during tropical forest restoration
Publisher: Wiley
Date: 08-02-2018
DOI: 10.1111/AVSC.12363
Resilience of agricultural soils to antibiotic resistance genes introduced by agricultural management practices
Publisher: Elsevier BV
Date: 02-2021
Overstorey composition shapes across‐trophic level community relationships in deciduous forest regardless of fragmentation context
Publisher: Wiley
Date: 26-01-2021
Abstract: Communities across trophic levels, and the functional roles they play, are vital for the sustained provision of ecosystem services. In forest systems, ersification of overstorey composition has been shown to be a key driver of bio ersity, but its influence on across‐trophic level relationships remains scarcely known. Species across trophic levels in varied overstorey compositions are also differentially susceptible to fragmentation context. We hypothesise that fragmentation will disrupt community relationships associated with particular overstorey compositions. We test this hypothesis using a tree ersity research platform across 53 deciduous woodland plots in central Belgium. We estimate species’ abundances within nine, generally taxonomic, community groups across trophic levels: understorey vegetation leaf miners and gall formers woodlice, millipedes carabid beetles, harvestmen, spiders, birds, bats. We use multiple co‐inertia analyses to examine how taxonomic and trophic role community matrices covary across gradients of overstorey composition, via three different tree species ersification pathways, and fragmentation. For all trophic role groups, across all plots, there was at least one significant pairwise comparison. Apart from comparisons involving bats, there was at least one significant pairwise correlation between taxonomic groups too. These results indicate correlated community matrices across trophic levels. Overstorey composition related to community tightness, that is, the level of co‐ordinated change among taxonomic and/or trophic role groups as revealed by multiple co‐inertia analyses. Notably, ersifying woodlands of beech Fagus sylvatica or red oak Quercus rubra with pedunculate oak Quercus robur correlated with increased taxonomic community tightness. Diversifying pedunculate oak forest stands with other overstorey species related to unchanged community tightness. Evidence was lacking for fragmentation affecting community tightness, singly or by interacting with overstorey composition. Synthesis . Overall, changing tree species composition and fragmentation level affected across‐trophic level community relationships differently. Yet, we demonstrated a clear signal that ersifying monoculture stands with particular species correlated with greater community tightness, and co‐ordinated change among sets of community groups, across trophic levels and regardless of fragmentation context. We postulate that having tighter community relationships suggests that measures to improve bio ersity at one trophic level (i.e. trees) could affect other groups, and their associated roles, in a co‐ordinated manner.
The combined effects of climate and canopy cover changes on understorey plants of the Hyrcanian forest biodiversity hotspot in northern Iran
Publisher: Wiley
Date: 08-11-2021
DOI: 10.1111/GCB.15946
Abstract: Understanding forest understorey community response to environmental change, including management actions, is vital given the understorey's importance for bio ersity conservation and ecosystem functioning. The Natural World Heritage Hyrcanian temperate forests (Iran) provide an ideal template for furnishing an appreciation of how management actions can mitigate undesired climate change effects, due to the forests’ broad environmental gradients, isolation from colonization sources and varied light environments. We used records of 95 understorey plant species from 512 plots to model their probability of occurrence as a function of contemporary climate and soil variables, and canopy cover. For 65 species with good predictive accuracy, we then projected two climate scenarios in the context of either increasing or decreasing canopy cover, to assess whether overstorey management could mitigate or aggravate climate change effects. Climate variables were the most important predictors for the distribution of all species. Soil and canopy cover varied in importance depending on understorey growth form. Climate change was projected to negatively affect future probabilities of occurrence. However, management, here represented by canopy cover change, is predicted to modify this trajectory for some species groups. Models predict increases in light‐adapted and generalist forbs with reduced canopy cover, while graminoids and ferns still decline. Increased canopy cover is projected to buffer an otherwise significant decreasing response of cold‐adapted species to climate change. However, increasing canopy cover is not projected to buffer the predicted negative impact of climate change on shade‐adapted forest specialists. Inconsistent responses of different species and/or growth forms to climate change and canopy cover reflect their complicated life histories and habitat preferences. Canopy cover management may help prevent the climate change induced loss of some important groups for bio ersity conservation. However, for shade‐adapted forest specialists, our results imply a need to adopt other conservation measures in the face of anticipated climate change.
Development and analysis of the Soil Water Infiltration Global database
Publisher: Copernicus GmbH
Date: 10-07-2018
DOI: 10.5194/ESSD-10-1237-2018
Abstract: Abstract. In this paper, we present and analyze a novel global database of soil infiltration measurements, the Soil Water Infiltration Global (SWIG) database. In total, 5023 infiltration curves were collected across all continents in the SWIG database. These data were either provided and quality checked by the scientists who performed the experiments or they were digitized from published articles. Data from 54 different countries were included in the database with major contributions from Iran, China, and the USA. In addition to its extensive geographical coverage, the collected infiltration curves cover research from 1976 to late 2017. Basic information on measurement location and method, soil properties, and land use was gathered along with the infiltration data, making the database valuable for the development of pedotransfer functions (PTFs) for estimating soil hydraulic properties, for the evaluation of infiltration measurement methods, and for developing and validating infiltration models. Soil textural information (clay, silt, and sand content) is available for 3842 out of 5023 infiltration measurements (∼ 76%) covering nearly all soil USDA textural classes except for the sandy clay and silt classes. Information on land use is available for 76 % of the experimental sites with agricultural land use as the dominant type (∼ 40%). We are convinced that the SWIG database will allow for a better parameterization of the infiltration process in land surface models and for testing infiltration models. All collected data and related soil characteristics are provided online in *.xlsx and *.csv formats for reference, and we add a disclaimer that the database is for public domain use only and can be copied freely by referencing it. Supplementary data are available at 0.1594/PANGAEA.885492 (Rahmati et al., 2018). Data quality assessment is strongly advised prior to any use of this database. Finally, we would like to encourage scientists to extend and update the SWIG database by uploading new data to it.
Restoring tropical forest composition is more difficult, but recovering tree-cover is faster, when neighbouring forests are young
Publisher: Springer Science and Business Media LLC
Date: 19-05-2020
Thermal differences between juveniles and adults increased over time in European forest trees
Publisher: Wiley
Date: 12-09-2021
Abstract: Woody species' requirements and environmental sensitivity change from seedlings to adults, a process referred to as ontogenetic shift. Such shifts can be increased by climate change. To assess the changes in the difference of temperature experienced by seedlings and adults in the context of climate change, it is essential to have reliable climatic data over long periods that capture the thermal conditions experienced by the in iduals throughout their life cycle. Here we used a unique cross‐European database of 2,195 pairs of resurveyed forest plots with a mean intercensus time interval of 37 years. We inferred macroclimatic temperature (free‐air conditions above tree canopies—representative of the conditions experienced by adult trees) and microclimatic temperature (representative of the juvenile stage at the forest floor, inferred from the relationship between canopy cover, distance to the coast and below‐canopy temperature) at both surveys. We then address the long‐term, large‐scale and multitaxa dynamics of the difference between the temperatures experienced by adults and juveniles of 25 temperate tree species. We found significant, but species‐specific, variations in the perceived temperature (calculated from presence/absence data) between life stages during both surveys. Additionally, the difference of the temperature experienced by the adult versus juveniles significantly increased between surveys for 8 of 25 species. We found evidence of a relationship between the difference of temperature experienced by juveniles and adults over time and one key functional trait (i.e. leaf area). Together, these results suggest that the temperatures experienced by adults versus juveniles became more decoupled over time for a subset of species, probably due to the combination of climate change and a recorded increase of canopy cover between the surveys resulting in higher rates of macroclimate than microclimate warming. Synthesis . We document warming and canopy‐cover induced changes in the difference of the temperature experienced by juveniles and adults. These findings have implications for forest management adaptation to climate change such as the promotion of tree regeneration by creating suitable species‐specific microclimatic conditions. Such adaptive management will help to mitigate the macroclimate change in the understorey layer.
TRY plant trait database – enhanced coverage and open access
Publisher: Wiley
Date: 31-12-2019
DOI: 10.1111/GCB.14904
Abstract: Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to bio ersity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on in idual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
How do trees respond to species mixing in experimental compared to observational studies?
Publisher: Wiley
Date: 10-09-2019
DOI: 10.1002/ECE3.5627
Understorey removal effects on tree regeneration in temperate forests: A meta‐analysis
Publisher: Wiley
Date: 23-11-2020
Abstract: The unwanted development of dense understorey vegetation composed of resource‐acquisitive, tall plant species competing strongly with tree regeneration can pose formidable problems for managers attempting to regenerate temperate forests. Despite many studies on the effects of understorey removal, no comprehensive review has summarised and quantified its effects on subsequent life stages of tree regeneration in temperate forests. We synthesised data from 32 experimental studies from temperate forest regions. We used meta‐analytic techniques to find general patterns in terms of the characteristics of the understorey, overstorey and characteristics of the regenerating tree species, which are most responsible for possible positive understorey removal effects on early life stages of tree regeneration, i.e. emergence, survival and growth. Both seedling survival and growth increased in response to understorey removal emergence did not show a clear pattern. Seedlings growing free from competition mainly increased their biomass growth (total and above‐ground), whereas diameter and height growth responded less. These positive effects were largest when removing denser understorey vegetation and under more open overstorey conditions. Multiple management options influenced the regeneration responses to understorey removal. For instance, growth of older, planted seedlings responded less to removal, whereas protection against large browsers increased growth responses. Tree species with differing strategies responded differently to understorey removal. Growth and survival responses of early‐successional species responded more strongly to understorey removal than mid‐ or late‐successional tree species. Synthesis and applications . Our study showed that understorey removal can have strong positive effects on tree regeneration across temperate forest contexts. The magnitude of these effects depended on overstorey and understorey conditions, but also on the type of tree species that is regenerated. Our results can support forest managers in their decision‐making and help assess under what conditions understorey removal will be most justified.
Drivers of above‐ground understorey biomass and nutrient stocks in temperate deciduous forests
Publisher: Wiley
Date: 11-12-2019
Interactive effects of past land use and recent forest management on the understorey community in temperate oak forests in South Sweden
Publisher: Wiley
Date: 22-06-2019
DOI: 10.1111/JVS.12770
Light availability and land‐use history drive biodiversity and functional changes in forest herb layer communities
Publisher: Wiley
Date: 24-01-2020
Related Organisations
University College For Agrarian And Environmental Pedagogy
Location: Austria
Related Funding Activities
No related grants have been discovered for Peter Strauss.