Browsing by Subject "Pollinators"

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  • Abdi, Abdulhakim; Carrié, Romain; Sidemo-Holm, William; Cai, Zhanzhang; Boke Olén, Niklas; Smith, Henrik G; Eklundh, Lars; Ekroos, Johan Edvard (2021)
    Increasing land-use intensity is a main driver of biodiversity loss in farmland, but measuring proxies for land-use intensity across entire landscapes is challenging. Here, we develop a novel method for the assessment of the impact of land-use intensity on biodiversity in agricultural landscapes using remote sensing parameters derived from the Sentinel-2 satellites. We link crop phenology and productivity parameters derived from time-series of a two-band enhanced vegetation index with biodiversity indicators (insect pollinators and insect-pollinated vascular plants) in agricultural fields in southern Sweden, with contrasting land management (i.e. conventional and organic farming). Our results show that arable land-use intensity in cereal systems dominated by spring-sown cereals can be approximated using Sentinel-2 productivity parameters. This was shown by the significant positive correlations between the amplitude and maximum value of the enhanced vegetation index on one side and farmer reported yields on the other. We also found that conventional cereal fields had 17% higher maximum and 13% higher amplitude of their enhanced vegetation index than organic fields. Sentinel-2 derived parameters were more strongly correlated with the abundance and species richness of bumblebees and the richness of vascular plants than the abundance and species richness of butterflies. The relationships we found between biodiversity and crop production proxies are consistent with predictions that increasing agricultural land-use intensity decreases field biodiversity. The newly developed method based on crop phenology and productivity parameters derived from Sentinel-2 data serves as a proof of concept for the assessment of the impact of land-use intensity on biodiversity over cereal fields across larger areas. It enables the estimation of arable productivity in cereal systems, which can then be used by ecologists and develop tools for land managers as a proxy for land-use intensity. Coupled with spatially explicit databases on agricultural land-use, this method will enable crop-specific cereal productivity estimation across large geographical regions.
  • Sahlberg, Ilse (Helsingin yliopisto, 2020)
    The crops, pollinator species and the agricultural conditions in the Northern agricultural district differ from those in most other areas. For example, in Finland the importance of insect pollination hasn't been researched very broadly. The oil plant widely cultivated in Finland, turnip rape (Brassica rapa subsp. Oleifera) has been discovered to benefit from insect pollination. The aim of this study is to examine whether the yield is different with turnip rapes where insect pollination is free or prevented, and how pollinator species and the number of flower visits affect the turnip rape yield. The study was mainly conducted in July 2017 on field parcels in Uusimaa. In the turnip rape fields, different pollinators and their visits in turnip rape flowers were monitored. To prevent insect pollination, the turnip rapes were covered with gauze bags before flowering began so that several plants came into one bag. This allowed cross-pollination. The total number of flower visits by pollinators was linked to the number of racemes and seeds of the plant: insect pollination decreased the number of racemes and increased the number of seeds per plant. The honeybees and hoverflies were a major group of pollinators explaining the turnip rape yield. Openly pollinated turnip rapes contained fewer racemes and more siliques and seeds per silique than enclosed plants. In addition, the weight of the seeds was higher In this study, it was discovered that there are differences between diverse pollinator species groups when it comes to pollination efficiency. It is still not clear how exactly the diversity of pollinator species affects pollination. Several studies show that after a certain threshold, flower visits by honey bees no more have an increasing effect on crop yields. Thus, other pollinators are also needed for optimal pollination. This study especially highlighted the significance of wild pollinators in pollinating crop plants. There seems to be demand for long-term monitoring of the pollination efficiency of different pollinator groups in the northern agricultural region
  • Järvelä, Riina (Helsingin yliopisto, 2014)
    The diversity of nature has declined significantly over the past decades. The agricultural diversity has the same trend and the agricultural environments includes of high-value habitats and their associated biodiversity. In the EU and in the Finnish environmental schemes, therefore, efforts have been made to protect and increase biodiversity. Since 2009, voluntary nature management fields have been part of the Finnish’s agri-environmental measures in the agri-environment scheme. These nature management fields include perennial grass fields, game fields, landscape fields and meadow fields. Nature management fields are used specifically to maintain the diversity of the agricultural environment. This study examined two types of nature management fields in summer of 2013. The variety of vascular plants, butterflies and bumblebees was observed in Uusimaa, Finland. The study consists of 40 field blocks, divided into perennial grassland fields (3-4 years) and meadow fields (over 8 years). Nature management field types differed from each other by vegetation, establishment and temporal change. The aim of this study was to provide information which can help in the design and management of nature management fields. The intention is to provide insight on what kind of vegetation could be used to encourage increase in the number and diversity of pollinators, as well as, what kind of the nature management fields promote environmental diversity in farmland. This study was conducted as part of Marjaana Toivonen's dissertation project, “Enhancing biodiversity and ecosystem services through environmental Fallows”. Vegetation was clearly influenced by the time and what was sown in the field. The old perennial grassland fields can preserve and safeguard the permanence of species. Young meadow fields are sown usually with flower seed mixtures. Thus, the abundance of flowering plants is high and the plants provide pollen and nectar for the insects. It was also found that the vegetation was divided according to the type of nature management fields. With pollinators, this trend was not observed as clearly. However, bumblebees were most common in meadow fields. Clear division between the types of fields was not seen in butterflies but they appeared to prefer grassland fields. This study shows that both grassland and meadow fields are needed for protecting biodiversity. Nature management fields have an important role as the multi-species vegetation patches which allow organisms to survive, get food and travel in otherwise monocultural farming environments.