This study investigated whether preschool children act on the understanding that identical-looking objects can no longer be re-identified once their positions change unnoticed, using an everyday task assessing the ability to avoid misidentification and comparing their performance with that of adults. Although children aged 4 to 7 years (N = 66) reliably and repeatedly identified which of five identical-looking nuggets was a Playmobil figure’s “favorite”, the majority (56 %) nevertheless failed to separate it when tidying up the five nuggets into two opaque bags. In contrast, all adults (N = 66) did so. The fact that the majority of children failed to separate the verbally marked nugget, despite knowing “which one it was”, indicates that they struggle to anticipate that the identity of very similar objects can be maintained only as long as identity-relevant spatial information is available, pointing to a still-developing concept of object identity. Older preschoolers tended to be more successful in separating the figure’s favorite nugget than younger ones, suggesting a developmental progression in how spatial identity criteria for objects are conceptualized. In a condition in which the figure’s favorite nugget was perceptually distinct (different color), 64 % of another group of children (N = 66) packed it separately, even though this was not necessary, indicating that their behavior was strongly driven by perceptual salience. Taken together, these findings suggest that many preschool children still struggle to use spatial criteria of identity to guide their behavior, even in a context that minimizes memory, attentional, and linguistic demands.
Ecological research is undergoing rapid change, driven both by the urgency of the environmental crisis and by the expanded opportunities for collaboration and networking in an increasingly interconnected world. Global collaborative efforts in ecology are needed to address large scale questions and draw strong inferences, but there is no simple recipe for success in scientific ecological networking. This perspective celebrates 20 years of the Mountain Invasion Research Network (MIREN), highlighting its key achievements in advancing the study of plant invasions and plant redistributions in mountain ecosystems and how these results may inform today’s most pressing ecological and conservation issues. As a decentralized global monitoring network built around regional nodes, MIREN has been able to generate replicated evidence across environmental gradients and biogeographical contexts. By surveying non-native plants in mountain regions around the world, the network has produced a uniquely comparable and robust dataset that allows fundamental ecological ideas to be tested with greater consistency and generality and contributes to conservation actions from local to global scales. Maintaining MIREN over the long term requires encouraging a new generation of researchers and conservation practitioners who can build on the network’s legacy while also addressing gaps in resourcing, technical capacity, and regional coverage.
Teachers’ mathematics-related beliefs have a substantial influence on their teaching. Given the variety of opportunities for teaching mathematical modeling supported by digital tools, related beliefs are crucial for classroom implementation. In this paper, we introduce a course that aims to prepare future mathematics teachers for teaching mathematical modeling in school using digital tools (focusing here on MathCityMap as an example). We used linear mixed models to analyze the development of 54 preservice teachers’ beliefs over the course, comparing them with 58 mathematics preservice teachers who did not attend the course. Results show an increase in course participants’ self-concepts about digital tools and mathematical modeling, as well as a tendency toward a more dynamic and less static mathematical worldview. There are hints that different course units contribute differently to the development of beliefs. These results suggest that such a course can provide a foundation for teachers to integrate digitally supported mathematical modeling into the classroom.
The search for predictors of plant diversity has challenged scientists for decades. Here we identify intense photosynthetically active radiation (PAR) as a major factor constraining plant species richness in global grasslands. We show that the strength of the negative relationship between species richness and PAR increases with increasing elevation and that species richness is more strongly correlated with intense PAR than with UV-B radiation, climate variables, and atmospheric nitrogen deposition. In addition to species richness, plant biomass was also negatively correlated with PAR at higher elevations, indicating that intense PAR also constrains plant biomass in montane grasslands. Furthermore, we show that the decrease in plant species richness with increasing PAR is mainly caused by a decrease in species richness of forbs, sedges, and rushes. In contrast, species richness of grasses was only negatively correlated with PAR at high elevations, and species richness of legumes was not significantly correlated with PAR. Our results suggest that PAR constrains plant species richness in global grasslands and limits the extent to which plant species of specific functional groups can migrate uphill in response to climate warming.
Biodiversity-ecosystem functioning (BEF) research has shown that ecosystem functioning and stability are closely linked to biodiversity. A cornerstone of this field is the BEF-China research platform, i.e. the world’s largest forest biodiversity experiment in subtropical China. It has demonstrated that tree diversity enhances productivity, carbon sequestration and ecosystem stability. However, the strength of these positive tree diversity effects varies widely across forests, possibly because higher trophic levels (such as herbivores and predators) mediate how biodiversity influences ecosystem functioning.To better understand how tree diversity influences higher trophic levels and their contributions to forest functioning, the German Research Foundation (DFG) is funding the project MultiTroph. MultiTroph quantifies species interactions and integrates them into food webs to understand when and why ecosystem functions change or destabilise with species loss. We expect that trophic interaction networks reveal how species share or separate their ecological roles, with more niche overlap in species-rich forests and more niche specialisation in species-poor forests.Here, we outline our conceptual framework and research goals. We are convinced that MultiTroph will expand existing BEF research and provide a more holistic understanding of the role of multi-trophic food webs in forest ecosystems.
