1-20 von 42 Publikationen

• Zeitschriftenartikel

#### The Role of Socio-Economic Determinants of Horse Farms for Grassland Management, Vegetation Composition and Ecological Value ﻿

Sustainability 2020; 12(24) p.1-18: Art. 10641
Socio-economic context is increasingly seen as a decisive factor for sustainable agricultural land use. The high prevalence of part-time farming and frequent lack of formal agricultural education within the equine sector are often seen as reasons why horse-grazed pastures do not fulfill their biodiversity potential. In spite of the substantial variability within horse farming, little is known about the relationship of socio-economic determinants with vegetation characteristics of horse-grazed grasslands. We surveyed 122 horse farms in Germany, classifying them into four socio-economic classes according to farm income type and farm managers’ agricultural education. We recorded farm structure parameters, grassland management practices and vegetation characteristics. Socio-economic class partly explained the great variability in farm structure that we observed. In contrast to our expectation, income type and agricultural education did not distinctly affect grassland management and were neither directly nor indirectly related to vegetation characteristics. Part-time farming and lack of agricultural education thus did not adversely affect the ecological value of horse-grazed grasslands. By contrast, both farm structure and paddock level management affected grassland vegetation and ecological value. Therefore, the socio-economic context of horse farms should be addressed in further research with strategies targeting the development of sustainable grassland management in horse keeping.
• Zeitschriftenartikel

#### Predicting Tree Sap Flux and Stomatal Conductance from Drone-Recorded Surface Temperatures in a Mixed Agroforestry System—A Machine Learning Approach ﻿

Remote Sensing 2020; 12(24) p.1-20: Art. 4070
Plant transpiration is a key element in the hydrological cycle. Widely used methods for its assessment comprise sap flux techniques for whole-plant transpiration and porometry for leaf stomatal conductance. Recently emerging approaches based on surface temperatures and a wide range of machine learning techniques offer new possibilities to quantify transpiration. The focus of this study was to predict sap flux and leaf stomatal conductance based on drone-recorded and meteorological data and compare these predictions with in-situ measured transpiration. To build the prediction models, we applied classical statistical approaches and machine learning algorithms. The field work was conducted in an oil palm agroforest in lowland Sumatra. Random forest predictions yielded the highest congruence with measured sap flux (r$^2$ = 0.87 for trees and r$^2$ = 0.58 for palms) and confidence intervals for intercept and slope of a Passing-Bablok regression suggest interchangeability of the methods. Differences in model performance are indicated when predicting different tree species. Predictions for stomatal conductance were less congruent for all prediction methods, likely due to spatial and temporal offsets of the measurements. Overall, the applied drone and modelling scheme predicts whole-plant transpiration with high accuracy. We conclude that there is large potential in machine learning approaches for ecological applications such as predicting transpiration.
• Zeitschriftenartikel

#### Review of the mite genus Krantzolaspina Datta & Bhattacharjee (Mesostigmata, Parholaspididae) with re-description of K. angustatus comb. nov. (Ishikawa) from Indonesia ﻿

ZooKeys 2020; 997 p.47-68
Herein, we update the diagnosis and description of the genus Krantzolaspina Datta & Bhattacharjee and provide a list of the three valid species including new combinations and synonyms, as follows: 1) Krant-zolaspina angustatus (Ishikawa, 1987) comb. nov. (= Indutolaelaps jiroftensis Hajizadeh et al., 2017 syn. nov.),2) K. rebatii Datta & Bhattacharjee, 1989 and 3) K. solimani (Metwali, 1983) comb. nov.Finally, we re-describe K. angustatus (Ishikawa, 1987) comb. nov. based on the holotype from Japan, voucher specimens from Iran and additional females that we found in soil samples from oil palm planta-tions in Sumatra, Indonesia.
• Zeitschriftenartikel

#### Evapotranspiration over agroforestry sites in Germany ﻿

Biogeosciences 2020; 17(20) p.5183-5208
In the past few years, the interest in growing crops and trees for bioenergy production has increased. One agricultural practice is the mixed cultivation of fast-growing trees and annual crops or perennial grasslands on the same piece of land, which is referred to as one type of agroforestry (AF). The inclusion of tree strips into the agricultural landscape has been shown – on the one hand – to lead to reduced wind speeds and higher carbon sequestration above ground and in the soil. On the other hand, concerns have been raised about increased water losses to the atmosphere via evapotranspiration (ET). Therefore, we hypothesise that short rotation coppice agroforestry systems have higher water losses to the atmosphere via ET compared to monoculture (MC) agriculture without trees. In order to test the hypothesis, the main objective was to measure the actual evapotranspiration of five AF systems in Germany and compare those to five monoculture systems in the close vicinity of the AF systems. We measured actual ET at five AF sites in direct comparison to five monoculture sites in northern Germany in 2016 and 2017. We used an eddy covariance energy balance (ECEB) set-up and a low-cost eddy covariance (EC-LC) set-up to measure actual ET over each AF and each MC system. We conducted direct eddy covariance (EC) measurement campaigns with approximately 4 weeks' duration for method validation. Results from the short-term measurement campaigns showed a high agreement between ETEC-LC and ETEC, indicated by slopes of a linear regression analysis between 0.86 and 1.3 ($R^2$ between 0.7 and 0.94) across sites. Root mean square errors of $LE_{EC-LC}$ vs. $LE_{EC}$ (where LE is the latent heat flux) were half as small as $LE_{ECEB}$ vs. $LE_{EC}$, indicating a superior agreement of the EC-LC set-up with the EC set-up compared to the ECEB set-up. With respect to the annual sums of ET over AF and MC, we observed small differences between the two land uses. We interpret this as being an effect of compensating the small-scale differences in ET next to and in between the tree strips for ET measurements on the system scale. Most likely, the differences in ET rates next to and in between the tree strips are of the same order of magnitude, but of the opposite sign, and compensate each other throughout the year. Differences between annual sums of ET from the two methods were of the same order of magnitude as differences between the two land uses. Compared to the effect of land use and different methods on ET, we found larger mean evapotranspiration indices (∑ET/∑P ) across sites for a drier than normal year (2016) compared to a wet year (2017). This indicates that we were able to detect differences in ET due to different ambient conditions with the applied methods, rather than the potentially small effect of AF on ET. We conclude that agroforestry has not resulted in an increased water loss to the atmosphere, indicating that agroforestry in Germany can be a land-use alternative to monoculture agriculture without trees.
• Zeitschriftenartikel

#### Knowledge of Student Teachers on Sustainable Land Use Issues–Knowledge Types Relevant for Teacher Education ﻿

Sustainability 2020; 12(20) p.1-20: Art. 8332
For restructuring educational processes and institutions toward Sustainable Development, teachers’ knowledge and competences are crucial. Due to the high relevance of teachers’ content knowledge, this study aimed to (i) assess Sustainable Development-relevant knowledge by differentiating between situational, conceptual and procedural knowledge, (ii) find out via item response theory modelling how these theoretically distinguished knowledge types can be empirically supported, and (iii) link the knowledge dimension(s) to related constructs. We developed a paper-and-pencil test to assess these three knowledge types (N = 314). A two-dimensional structure that combines situational and conceptual knowledge and that distinguishes situational/conceptual knowledge from procedural knowledge, fits the data best (EAP/PV situational/conceptual: 0.63; EAP/PV procedural: 0.67). Student teachers at master level outperformed bachelor level students in situational/conceptual knowledge but master level students did not differ from students at bachelor level regarding procedural knowledge. We observed only slight correlations between the two knowledge dimensions and the content-related motivational orientations of professional action competence. Student teachers’ deficits in procedural knowledge can be attributed to the small number of Education for Sustainable Development-relevant courses attended. Systematically fostering procedural knowledge in teacher education could promote achieving cognitive learning objectives associated with Sustainable Development Goals in the long term.
• Zeitschriftenartikel

#### A new dataset on plant occurrences on smallislands, including species abundances andfunctional traits across different spatial scales ﻿

Biodiversity Data Journal 2020; 8 p.1-16: Art. e55275
Background We introduce a new dataset of woody plants on 60 small tropical islands located in the Raja Ampat archipelago in Indonesia. The dataset includes incidence, abundance and functional trait data for 57 species. All islands were sampled using a standardised transect and plot design providing detailed information on plant occurrences at different spatial scales ranging from the local (plot and transect scale) to the island scale. In addition, the dataset includes information on key plant functional traits linked to species dispersal, resource acquisition and competitive strategies. The dataset can be used to address ecological questions connected to the species-area relationship and community assembly processes on small islands and in isolated habitats. New information The dataset yields detailed information on plant community structure and links incidence, abundance and functional trait data at different spatial scales. Furthermore, this is the first plant-island dataset for the Raja Ampat archipelago, a remote and poorly studied region, and provides important new information on species occurrences.
• Zeitschriftenartikel

#### Quantitative Modelling and Perspective Taking: Two Competencies of Decision Making for Sustainable Development ﻿

Sustainability 2020; 12(17) p.1-32: Art. 6980
Land use change, natural resource use and climate change are challenging Sustainable Development issues (SDGs 13–15). Fostering the competencies to deal with such issues is one core task for current educational endeavors. Among these competencies, decision-making competencies are central. In detail, we investigate how learners evaluate alternative decision-making options to improve existing competence models. We exemplify our competence modelling approach using the designation of a Marine Protected Area. The cross-sectional sample consists of secondary school students and student teachers (N = 760). Partial Credit modelling shows that quantitative modelling of decision-making options is a different competence dimension than perspective taking if contextualized for Sustainable Development. In quantitative modelling, mathematical modelling is used to evaluate and reflect on decision-making options. Perspective taking covers the ability to consider different normative perspectives on Sustainable Development issues. Both dimensions show plausible (latent) correlations with related constructs within the nomological net, i.e., with qualitative arguing, economic literacy, mathematical competencies, reading competencies and analytical problem solving. Furthermore, person-abilities increase with level of education for both dimensions. The identified competence dimensions quantitative modelling and perspective taking were successfully modelled and shown to be distinct; the resulting measuring instrument is reliable and valid.
• Zeitschriftenartikel

#### Trophic level and basal resource use of soil animals are hardly affected by local plant associations in abandoned arable land ﻿

Ecology and Evolution 2020; 10(15) p.8279-8288
Plants provide resources and shape the habitat of soil organisms thereby affecting the composition and functioning of soil communities. Effects of plants on soil communities are largely taxon‐dependent, but how different functional groups of herbaceous plants affect trophic niches of individual animal species in soil needs further investigation. Here, we studied the use of basal resources and trophic levels of dominating soil meso‐ and macrofauna using stable isotope ratios of carbon and nitrogen in arable fallow systems 3 and 14–16 years after abandonment. Animals were sampled from the rhizosphere of three plant species of different functional groups: a legume (Medicaco sativa), a nonlegume herb (Taraxacum officinale), and a grass (Bromus sterilis). We found virtually no consistent effects of plant identity on stable isotope composition of soil animals and on thirteen isotopic metrics that reflect general food‐web structure. However, in old fallows, the carbon isotope composition of some predatory macrofauna taxa had shifted closer to that of co‐occurring plants, which was particularly evident for Lasius, an aphid‐associated ant genus. Trophic levels and trophic‐chain lengths in food webs were similar across plant species and fallow ages. Overall, the results suggest that variations in local plant diversity of grassland communities may little affect the basal resources and the trophic level of prey consumed by individual species of meso‐ and macrofauna belowground. By contrast, successional changes in grassland communities are associated with shifts in the trophic niches of certain species, reflecting establishment of trophic interactions with time, which shapes the functioning and stability of soil food webs.
• Zeitschriftenartikel

#### Land-Use and Health Issues in Malagasy Primary Education—A Delphi Study ﻿

Sustainability 2020; 12(15) p.1-31: Art. 6212
Education for Sustainable Development (ESD) plays a key role in Sustainable Development. In low-income countries like Madagascar, this key role is particularly relevant to primary education. However, the curricula lack a comprehensive ESD approach that incorporates regional issues. In Madagascar, sustainable land-use practices (Sustainable Development Goals 12, 15) and health prevention (SDGs 2, 3, 6) are educational challenges. Procedural knowledge allows problem-solving regarding unsustainable developments. We adapted and further developed a measure of ESD-relevant procedural knowledge. Considering curricula, sustainability standards, research, and a two-round Delphi study (n = 34 experts), we identified regionally relevant land-use practices and health-protective behavior. After the experts rated the effectiveness and possibility of implementation of courses of actions, we calculated an index of what to teach under given Malagasy (regional) conditions. Combined with qualitative expert comments, the study offers insights into expert views on land-use and health topics: For example, when teaching ESD in Northeast Madagascar, sustainable management of cultivation and soil is suitable, particularly when linked to vanilla production. Health-protective behavior is ultimately more difficult to implement in rural than in urban areas. These results are important for further curricula development, for ESD during primary education, and because they give insights into the topics teacher education should address.
• Zeitschriftenartikel

#### Target‐oriented habitat and wildlife management: estimating forage quantity and quality of semi‐natural grasslands with Sentinel‐1 and Sentinel‐2 data ﻿

Remote Sensing in Ecology and Conservation p.1-18
Semi‐natural grasslands represent ecosystems with high biodiversity. Their conservation depends on the removal of biomass, for example, through grazing by livestock or wildlife. For this, spatially explicit information about grassland forage quantity and quality is a prerequisite for efficient management. The recent advancements of the Sentinel satellite mission offer new possibilities to support the conservation of semi‐natural grasslands. In this study, the combined use of radar (Sentinel‐1) and multispectral (Sentinel‐2) data to predict forage quantity and quality indicators of semi‐natural grassland in Germany was investigated. Field data for organic acid detergent fibre concentration (oADF ), crude protein concentration (CP ), compressed sward height (CSH ) and standing biomass dry weight (DM ) collected between 2015 and 2017 were related to remote sensing data using the random forest regression algorithm. In total, 102 optical‐ and radar‐based predictor variables were used to derive an optimized dataset, maximizing the predictive power of the respective model. High $R^2$ values were obtained for the grassland quality indicators oADF ($R^2$ = 0.79, RMSE = 2.29%) and CP ($R^2$ = 0.72, RMSE = 1.70%) using 15 and 8 predictor variables respectively. Lower R 2 values were achieved for the quantity indicators CSH ($R^2$ = 0.60, RMSE = 2.77 cm) and DM ($R^2$ = 0.45, RMSE = 90.84 g/m²). A permutation‐based variable importance measure indicated a strong contribution of simple ratio‐based optical indices to the model performance. In particular, the ratios between the narrow near‐infrared and red‐edge region were among the most important variables. The model performance for oADF , CP and CSH was only marginally increased by adding Sentinel‐1 data. For DM , no positive effect on the model performance was observed by combining Sentinel‐1 and Sentinel‐2 data. Thus, optical Sentinel‐2 data might be sufficient to accurately predict forage quality, and to some extent also quantity indicators of semi‐natural grassland.
• Zeitschriftenartikel

#### Effect of Grazing System on Grassland Plant Species Richness and Vegetation Characteristics: Comparing Horse and Cattle Grazing ﻿

Sustainability 2020; 12(8) p.1-17: Art. 3300
Horses are of increasing relevance in agriculturally managed grasslands across Europe. There is concern to what extent grazing with horses is a sustainable grassland management practice. The effect of longer-term horse grazing on the vegetation characteristics of grasslands has received little attention, especially in comparison to grazing cattle. Our study analyses the relative importance of grazing system (grazer species and regime) and grassland management for vegetation characteristics in grasslands as indicator for sustainable management. We monitored grassland vegetation in western central Germany and compared paddocks grazed by horses under two different regimes, continuous (HC) vs. rotational (HR), to paddocks grazed by cattle (C) under similar trophic site conditions. We observed more plant species and more High Nature Value indicator species on HC compared to C. The vegetation of C was more grazing tolerant and had higher forage value than HC. Regardless of the grazing regime, the competitive component was lower, the stress-tolerant component higher and the floristic contrast between patch-types stronger on HC and HR paddocks compared to C. Species richness was strongly influenced by the extent of the floristic contrast. Our results emphasize the potential of horse grazing for biodiversity in agriculturally managed grasslands.
• Zeitschriftenartikel

#### Performance of Modern Varieties of Festuca arundinacea and Phleum pratense as an Alternative to Lolium perenne in Intensively Managed Sown Grasslands ﻿

Agronomy 2020; 10(4) p.1-13: Art. 540
In future, grass swards need to be adapted to climate change and interactions of management and site are becoming more important. The persistence of Lolium perenne on peatland or during dry periods is limited and alternative forage species are required. We tested the performance of a modern variety of Festuca arundinacea and Phleum pratense as an alternative to Lolium perenne on clay, peat, and sandy soils. Each of these grasses was sown as main species in mixture with Poa pratensis and Trifolium repens and the mixtures were subjected to different frequencies of defoliation. Differences in yield proportions in the third year were significantly influenced by main species, site and their interaction. Remaining mass proportions of main species after three years were smallest on peat; on all sites Festuca arundinacea showed the highest persistence and largest yield, followed by Lolium perenne. Mass proportions of Phleum pratense were small on peat soils and Phleum had been replaced there by Holcus lanatus, and by Lolium perenne and Poa pratensis on the clay and sandy soils. We conclude that the choice of grass species in mixtures is a management tool to control stability and productivity of grass swards under specific site conditions.
• Zeitschriftenartikel

#### Airborne Tree Crown Detection for Predicting Spatial Heterogeneity of Canopy Transpiration in a Tropical Rainforest ﻿

Remote Sensing 2020; 12(4) p.1-16: Art. 651
Tropical rainforests comprise complex 3D structures and encompass heterogeneous site conditions; their transpiration contributes to climate regulation. The objectives of our study were to test the relationship between tree water use and crown metrics and to predict spatial variability of canopy transpiration across sites. In a lowland rainforest of Sumatra, we measured tree water use with sap flux techniques and simultaneously assessed crown metrics with drone-based photogrammetry. We observed a close linear relationship between individual tree water use and crown surface area (R$^2$ = 0.76, n = 42 trees). Uncertainties in predicting stand-level canopy transpiration were much lower using tree crown metrics than the more conventionally used stem diameter. 3D canopy segmentation analyses in combination with the tree crown–water use relationship predict substantial spatial heterogeneity in canopy transpiration. Among our eight study plots, there was a more than two-fold difference, with lower transpiration at riparian than at upland sites. In conclusion, we regard drone-based canopy segmentation and crown metrics to be very useful tools for the scaling of transpiration from tree- to stand-level. Our results indicate substantial spatial variation in crown packing and thus canopy transpiration of tropical rainforests.
• Zeitschriftenartikel

#### Using a Citizen Science Approach with German Horse Owners to Study the Locomotion Behaviour of Horses on Pasture ﻿

Sustainability 2020; 12(5) p.1-12: Art. 1835
Engaging farmers as citizen scientists may be a cost-effcient way to answering applied research questions aimed at more sustainable land use. We used a citizen science approach with German horse farmers with a dual goal. Firstly, we tested the practicability of this approach for answering ‘real-life’ questions in variable agricultural land-use systems. Secondly, we were interested in the knowledge it can provide about locomotion of horses on pasture and the management factors influencing this behaviour. Out of 165 volunteers, we selected 40 participants to record locomotion of two horses on pasture and provide information on their horse husbandry and pasture management. We obtained complete records for three recording days per horse from 28 participants, resulting in a dataset on more individual horses than any other Global Positioning System study published in the last 30 years. Time spent walking was greatest for horses kept in box-stall stables, and walking distance decreased with increasing grazing time. This suggests that restrictions in pasture access may increase stress on grass swards through running and trampling, severely challenging sustainable pasture management. Our study, involving simple technology, clear instructions and rigorous quality assessment, demonstrates the potential of citizen science actively involving land managers in agricultural research.
• Zeitschriftenartikel

#### The Economy of Canopy Space Occupation and Shade Production in Early- to Late-Successional Temperate Tree Species and Their Relation to Productivity ﻿

Forests 2020; 11(3) p.1-18: Art. 317
Light capture is linked to occupation of canopy space by tree crowns, which requires investment of carbon and nutrients. We hypothesize that (i) late-successional trees invest more in casting shade than in occupying space than early-successional trees, and (ii) shade production and crown volume expansion are generally greater in more productive species. For six Central European early-successional (Betula pendula, Pinus sylvestris), mid/late-successional (Quercus petraea, Carpinus betulus), and late-successional tree species (Tilia cordata, Fagus sylvatica), we measured through full-tree harvests (1) crown volume, (2) the costs of canopy space exploration (carbon (C) and nutrients invested to fill crown volume), of space occupation (annual foliage production per volume), and of shade production (foliage needed to reduce light transmittance), and (3) related the costs to aboveground productivity (ANPP). The C and nutrient costs of canopy volume exploration and occupation were independent of the species’ seral stage, but increased with ANPP. In contrast, the cost of shade production decreased from early-to late-successional species, suggesting that the economy of shade production is more decisive for the competitive superiority of late-successional species than the economy of canopy space exploration and occupation.
• Zeitschriftenartikel

#### Diverse Swards and Mixed-Grazing of Cattle and Sheep for Improved Productivity ﻿

Frontiers in Sustainable Food Systems 2020; 3 p.1-14: Art. 125
Increasing sward phytodiversity has been suggested as having potential to increase primary production of grasslands, but whether any such gains are converted into secondary production, through improved performance of grazing livestock, remains uncertain. Animal production by cattle and sheep can also be enhanced by mixed-grazing. To our knowledge, this effect has never been studied in relation to differences in sward phytodiversity. Therefore, a rotational grazing experiment was conducted over 5 years (2007–2011) on permanent grassland in Germany using sheep and cattle in mono- (single-species) or mixed-grazing of swards differing in plant species richness. Herbicides against dicotyledonous plant species were used to create different sward types: species-poor, grass-dominated swards in contrast to untreated “diverse” control swards. We found no differences in herbage production between the sward types. However, compared to the grass-dominated sward, the diverse sward showed greater concentrations of crude protein and lower contents of acid detergent fiber in the herbage dry-matter. Lamb live weight gains were slightly greater on the diverse-swards (P < 0.05), but calf performance was unaffected by sward type. Mixed-grazing increased daily average live weight gains of suckler cows (g cow⁻¹ d⁻¹) (P < 0.05) as well as area-related daily live weight gains (kg ha⁻¹ d⁻¹) and total live weight gains (kg ha⁻¹) during the complete grazing season (P < 0.001). This indicates advantages of combining livestock species, attributed to complementary pasture use. We suggest that mixed-grazing of cattle and sheep on phytodiverse swards is an effective and sustainable means to enhance ecological and agronomic traits such as livestock production and plant species conservation. Lamb production especially showed benefits under mixed-grazing, with a 17% increase in live weight gain. Compared to the grass-dominated sward, diverse swards resulted in an average 12% increase of live weight gains (across grazing systems and livestock species).
• Zeitschriftenartikel

#### Facultative mycorrhizal associations promote plant naturalization worldwide ﻿

Ecosphere 2019; 10(11): Art. e02937
Mycorrhizal symbiosis has received relatively little attention as a mechanism explaining plant naturalizations at a global scale. Here, we combined data on vascular plant species occurrences in over 840 mainland and island regions from the Global Naturalized Alien Flora (GloNAF) database with up-to-date databases of mycorrhizal associations. We tested whether the mycorrhizal type (arbuscular, AM; ectomycorrhizal, ECM; and non-mycorrhizal, NM) and status (facultative and obligate) were associated with two measures of naturalization success, (1) naturalization incidence (reflecting the ability to naturalize, and expressed as whether or not a plant species is recorded as naturalized anywhere in the world) and (2) naturalization extent (expressed as the number of GloNAF regions where the species occurs). In total, we found information on mycorrhizal type and status for 3211 naturalized plant species and 4200 non-naturalized plant species. Mycorrhizal plant species, both AM and ECM, were more likely to be naturalized and naturalized to a greater extent than NM plants. The effect of being an AM species was always stronger, with AM species having a greater naturalization extent than ECM species. Being the same mycorrhizal type or status, annual species were generally more likely to be naturalized than perennials. Species with facultative mycorrhizal associations were more successful than those with obligate mycorrhizal associations, but both groups tended to have a greater chance of being naturalized than NM species. These results indicate that being NM is generally less favorable for naturalization. Overall, our results confirm, at the global scale, those of regional studies that facultative association with AM provides plant species with a naturalization advantage. For the first time, we have shown that being mycorrhizal contributes not only to the size of the naturalized range, reflecting the ability to spread, but also to the ability to become naturalized in the first instance.
• Zeitschriftenartikel

#### Response of tree diversity and community composition to forest use intensity along a tropical elevational gradient ﻿

Applied Vegetation Science 2019; 23(1) p.69-79
Question: Land-use change and intensification are currently the most pervasive threats to tropical biodiversity. Yet, their effects on biodiversity change with eleva-tion are unknown. Here, we examine how tree diversity and community composition vary with elevation and how the effects of forest use intensity on tree diversity and community composition change within elevations.Location: Eastern slopes of the Cofre de Perote mountain, state of Veracruz, Mexico.Methods: We assessed tree diversity and composition using a sampling design in which elevation was crossed with three levels of forest use intensity: old-growth, degraded, and secondary forests. We established 120 20 m × 20 m forest plots, lo-cated at eight sites between 0 m and 3,545 m. At each site, five replicate plots were inventoried for each level of forest use intensity.Results: Our analyses revealed an interactive effect between elevation and forest use intensity affecting tree diversity and community composition along the eleva-tional gradient. Contrasting effects of forest use intensity within elevation resulted in tree diversity following a low-plateau pattern for old-growth and a bimodal pat-tern for degraded and secondary forests. Along the entire elevational gradient, there were 217 tree species distributed within 154 genera and 80 families. Species accu-mulation curves revealed that forests at 0 m and 1,500 m elevation showed differ-ences in species richness among forest use intensities. In contrast, species richness did not differ between old-growth forest and the other forest use intensities in five of the eight studied elevations. In terms of community composition, secondary forests differed from old-growth and degraded forests.Conclusion: Our results suggest that the interactive effects of elevation and for-est use intensity change tree diversity patterns and community composition along a tropical elevational gradient. Degraded forests were similar to old-growth forests in terms of species diversity and composition, suggesting that they may act as a safe-guard of tree diversity in human-dominated tropical landscapes.
• Zeitschriftenartikel

#### TRY plant trait database – enhanced coverage and open access ﻿

Global Change Biology 2019; 26(1) p.119-188
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 biodiversity 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 individual 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.
• Zeitschriftenartikel

#### Student Teachers’ Knowledge to Enable Problem-Solving for Sustainable Development ﻿

Sustainability 2020; 12(1): Art. 79
Education is a central strategy in terms of sustainable development (SD) and can contribute to solving global challenges like biodiversity loss and climate change. Content knowledge represents one base for teaching education for sustainable development (ESD). Therefore, identifying teaching and learning prerequisites regarding SD challenges in teacher education is crucial. The focus of the paper was to assess and learn more about student teachers’ procedural knowledge regarding issues of biodiversity and climate change, by using an expert benchmark. The aims of the study are to describe and identify (i) di erences between students’ and experts’ e ectiveness estimations, (ii) di erences in bachelor and master students’ procedural knowledge, and (iii) di erences between procedural knowledge of students studying di erent ESD-relevant subjects. Student teachers at eight German universities (n = 236) evaluated the e ectiveness of solution strategies to SD challenges. The results showed high deviations in the e ectiveness estimations of experts and students and, therefore, di ering procedural knowledge. The lack of student teachers’ interdisciplinary knowledge to reduce biodiversity loss and climate change seemed to be largely independent of their study program and ESD-relevant subject. One reason for this may be the generally low number of ESD-relevant courses they attended. This study suggests further longitudinal research in order to make clear statements about changes in SD-related knowledge during teacher education.