Study Of Pollinator Diversity Under Different Time And Habitat Types

Biodiversity is the foundation of the agricultural ecosystem,which plays an important role in maintaining agricultural ecosystem stability,material recycle and so on.To grain stable and increased production requires the agriculture biodiversity to provide necessary ecological services in the future.Habitat loss and fragmentation caused by the land-use pattern of modern agriculture have become an important cause of global biodiversity loss.At the same time,species diversity tends to show a different pattern under different time scales.Although land use patterns and time scales play an important role when we study species diversity in fragmented habitats,the research in this area is rare.To study the influence of time scales and habitat types on pollinator communities,pollinator richness were surveyed in different areas with different landscape complexity.Our aim was to study:(1)the difference of species richness and biodiversity of three kinds of pollinating insects(honey bees,butterflies and syrphus flies)under different time scales;(2)the effects of habitat types on three kind of pollinating insects in farmland ecosystem;(3)the sampling estimation of pollinator diversity among various sample numbers and habitat types.This was an innovative approach combining different time scales across habitat types and landscape gradients.Knowledge of how a species community responds to the surrounding landscape will be helpful to understand the biodiversity patterns,and this study will provide a reference for the formulation of strategies of the conservation and restoration of agricultural biodiversity.This study sampled respectively in four periods:March 2015 and 2016(during oilseed rape flowering)and April 2015 and 2016(after oilseed rape flowering).We investigated the pollination insect in different habitat types,and CCA was used to analyze which habitat types of farmland has the strongest impact on the pollinator community of farmland ecosystem.In this study,we also focused on species richness of pollinating insects in agricultural landscapes and analyzed how semi-natural habitat types and landscape composition contribute to reliable estimates.We also compared pollinating insects richness predictions based on samples collected only in one habitat type(semi-natural habitats or oilseed rape fields)with samples placed systematically throughout the landscape which covering all available habitat types.The results showed that:(1)There were 1960 Apoidea insects had been collected,which belongs to 3 families and 15 species,including 839 honey bees(Apis mellifera Ligustica Spinola),and 1299 wild bees;952 butterflies,most of which were Pieris rapae;and 221 syrphus flies.The results show that the local pollinator community in the investigated area has relatively abundant species richness and diversity with large quantities.The dominant species were Apis mellifera Ligustica Spinola,Seladonia Magnus Ebmer and Pieris rapae Linnaeus.The number of Apis mellifera and Pieris rapae were significant higher during oilseed rape flowering than after oilseed rape flowering;the number and types of syrphus flies were not significant during oilseed rape flowering and after oilseed rape flowering.In contrast with 2015,the total species number of wild pollinators in 2016 relatively increased,while the number of honeybees declined.(2)Wether the oilseed rape were during the flowering period or not and the cultivated area of oilseed rape had significant effects on pollinator abundance and pollinator community structure.Pollinator community richness index,evenness index and diversity index were higher during oilseed rape flowering than after oilseed rape flowering.CCA analysis results showed that the area of oilseed rape was the main type of landuse effecting pollinator community structure,followed by the wasteland,the ridge,ditch and semi-natural habitats.We hypothesized that the proportion of flowering plants perhaps was a determinant of pollinator species richness.(3)Sampling only in one habitat type would lead to an estimation bias in landscape pollinator species richness.Even if the number of samples in this habitat was increased,the estimation bias still exists.Species richness can be overestimated when only sampled in semi natural habitats,meanwhile species richness is underestimated only in oilseed rape fields.In addition,the number of samples also affects the accuracy of estimation,and as the number of samples increases,the estimation accuracy also increases.