Importance of bumble bee community evenness for crop pollination : a simulation analysis of Swedish red clover seed production

The red clover seed production systems are dependent on pollinators for increase in red clover seed yield and its stability. When compared to domesticated honey bees, the wild bumble bees are highly efficient in pollinating the red clover crop due to its relatively longer tongue length. Longer dependence on single pollinator species i.e., honey bees has proved that reliance on single pollinator population is highly inefficient especially when the highly managed systems are prone to ecological surprises like colony collapse disorder. Therefore, global agro-ecosystem management has begun to increase their efforts of harnessing the pollination potential from diverse wild pollinator communities like bumble bees and non-bee pollinators. However, the agricultural intensification led landscape and environmental homogenisation has caused the populations of the wild pollinators decline, resulting in reduced pollination service from wild bumble bee diversity, necessitating conservation of bumble bees. Among bumble bees the long tongue (LT) bumble bees are highly efficient pollinators, whereas short tongue (ST) bumble bees are relatively least efficient or unproductive because of their short tongue length and their one third proportion engages in robbery of nectar without pollinating the flowers. However, ST bumble bees are highly mobile and highly populated generalist functional group, contrasting specialist LT species in red-clover production systems. To investigate the impact of declining evenness in this 10-species community comprising of 5 LT and 5 ST, the empirical proportional abundance data from historic field investigations (1940’s, 1960’s & 2010) were modelled as temporal replication scenarios for 100 years in a model called FunBumble prepared for this study using empirical parameter estimates. The early 1940’s & 1960’s scenarios had one dominant and 3 co-dominant identities and the contemporary 2010 scenarios had one dominant and co-dominant identity. Throughout since 1960’s to 2010, B. terrestris is the dominant species. Thus, the 10-species community comprised of totally 5 dominant species, these each dominance identities taken as scenarios were designed as nested evenness levels namely, high evenness, medium evenness and low evenness scenarios. The FunBumble model investigation of these scenarios, showed that as community evenness increased the temporal seed yield stability too increased due to portfolio effect and species asynchrony in the presence high evenness. Whereas, the low magnitude increases or decreases of temporal productivity depended largely on sign of selection effect and contributions of co-dominance identities. For example, when unproductive ST species B. terrestris is dominant due to negative selection effect, the co-dominant highly productive LT species contributed positively resulting in over yielding of productivity and enhanced species co-existence causing positive influence on biodiversity. This mechanistic understanding of biodiversity, productivity and stability relationship of realistic B. terrestris dominance identity scenarios showed that the bumble bee community composition since 1940’s in red clover production system had acted as species co-existence promoting buffering mechanism under the presence of selection processes like landscape and environmental homogenisation due to agricultural intensification. Especially the contemporary (2010) least evenness scenario with no LT species as co-dominant illustrates the reasons for current decline in both stability and productivity of red clover seed yield. This necessitates, the need for local and landscape scale management measures for increasing relative abundance of LT species, through nesting and floral resource facilitation in crop production systems

Effect of restoration and surrounding grassland proportion on the dung beetle metapopulation abundance in the fragmented semi-natural grasslands : dung beetles in restored semi-natural grasslands

The importance of landscape composition surrounding the local habitats is increasingly recognized, especially with goal of enhancing the understanding about its role in various conservation frameworks. The dung beetles which depend on human mediated ephemeral resources (Dung from domestic animal) gives a valuable opportunity for understanding landscape moderated effects of both the landscape structure as well as sensitive grazing management on the local populations of semi-natural grasslands in Sweden. The objectives of this study was to investigate the influence of surrounding landscape grassland proportion gradient and grassland management history on dung beetle species richness and composition. Dung pats (n=200) where collected from the 10 pairs (restored and continuously managed) of pastures. The local abundance and species richness was statistically tested using GLM and regression analysis for the effect of habitat type (restored or continuously grazed grassland) &/or grassland proportion (at 1km & 5km scale) and time since restoration respectively. The field sampling yielded 4784 beetles of 17 species (Aphodius and Geotrupes) belonging to 14 functional guilds of which two generalist species A. rufipes and A. rufus itself contributed 2664 individuals. The total abundance was higher in restored pastures and total species richness was higher in continuously managed pastures. GLM analysis showed that independent of surrounding landscape grassland proportion the habitat type had an effect on abundance of A. fossor (Pasture specialist) and domestic feeder guild positively on continuously managed pastures. The 1km scale surrounding grassland proportion had positive influence on total abundance and abundance of various functional guilds confounded by metapopulation dynamics of generalist species in respective guilds. Whereas 5km scale grassland proportion had both independent and interactive (with habitat management) positive influence on species specific models. This study concludes surrounding grassland proportion influences the local dung beetle abundance and the restored pastures has a delay in recovery of the population abundance of pasture specialists and intermediate species guild similar to continuously managed pastures. Further research is needed to increase the understanding about the persistence of species and species guilds which experience narrow niches in their life history

Tropical Grassland Ecosystems and Climate Change

Grasses are unique group of flowering plants that form the foundation for the trophic structure in terrestrial communities. The grasses are found in every conceivable habitat where plants can thrive – from sea to deserts and from wetlands to peaks of highest mountains. The grasses form a distinct biome – a major ecological formation in the global classification of vegetation

See Through the Fog: Curriculum Learning with Progressive Occlusion in Medical Imaging

In recent years, deep learning models have revolutionized medical image interpretation, offering substantial improvements in diagnostic accuracy. However, these models often struggle with challenging images where critical features are partially or fully occluded, which is a common scenario in clinical practice. In this paper, we propose a novel curriculum learning-based approach to train deep learning models to handle occluded medical images effectively. Our method progressively introduces occlusion, starting from clear, unobstructed images and gradually moving to images with increasing occlusion levels. This ordered learning process, akin to human learning, allows the model to first grasp simple, discernable patterns and subsequently build upon this knowledge to understand more complicated, occluded scenarios. Furthermore, we present three novel occlusion synthesis methods, namely Wasserstein Curriculum Learning (WCL), Information Adaptive Learning (IAL), and Geodesic Curriculum Learning (GCL). Our extensive experiments on diverse medical image datasets demonstrate substantial improvements in model robustness and diagnostic accuracy over conventional training methodologies.Comment: 20 pages, 3 figures, 1 tabl

Some Experimental Investigations for the Development of Integrated Model of a Structure with the Controllable Fluid Damper

This paper presents a brief overview of research being conducted in the area of Seismic Hazards Mitigation. The focus of the study has been on the development of integrated model of a structure with controllable fluid damper. The damper is used with an objective of reducing the dynamic wave propagation potential in the structure, upon the structural excitation. Before its employability to serve the intended purpose, the system identification and the model validation are the pre-requisites for the optimal functioning of the damper. A phenomenological model of the controllable fluid damper-Magnetorheological damper is used along with other Smart materials in the experiments conducted under controlled conditions. The experimental results are used to verify the integrated system model. The experimental results obtained indicate that high performance can be attained with controllable fluid damper to meet the requirements associated with seismic response reduction in civil engineering structures