| Biodiversity is the basis of agro-ecosystems,which plays an important huge role in maintaining the stability and material circulation of agro-ecosystems.Non-agricultural habitats such as nature and semi-natural are embedded in the agricultural landscape ecosystem,the existence of non-agricultural habitats provides a rich source of food for pollinating insects,suitable habitats and breeding grounds,shelters and other resources,while maintaining agricultural landscapes.The stability of the level of biodiversity plays a crucial role.Pollination of crops and wild plants is one of the most important ecosystem services,pollinators play a vital role in it.On the other hand,the pollinating insect group can reflect the ecological environment by changing its own population structure and quantity and its response to the environment.Landscape mosaics composed of different types of semi-natural habitats(such as farmland boundaries,flaky woodlands,ditches and hedges)and intensive agricultural land,resulting in heterogeneous agricultural landscapes at multiple scales.The existence of heterogeneity is important for maintaining the level of biodiversity in agro-ecosystems.Changes in land use patterns in intensive agricultural production patterns have led to increased habitat fragmentation in agricultural landscapes,and habitat destruction is a major threat to ecosystems,an important cause of the sharp decline in global biodiversity in recent years.In agro-ecosystems,the loss of pollinator diversity leads to a decline in agricultural production levels,which is detrimental to the stability of ecosystem services and functions.In order to explore the diversity characteristics of pollinator communities under large landscape scales,Gongyi City and Minquan County were selected as research areas in the landscape of western Henan and the landscape of Yudong Plain in this study.The three habitat types of farmland,plantation andnatural forest were taken as research objects to explore the influence of landscape heterogeneity level on pollinator community structure at landscape scale and habitat scale.On the landscape scale,the remote sensing images of the two study areas were extracted for vector analysis,the landscape index was extracted,and the land use classification map was made to explore the differences in landscape heterogeneity between the two study areas.Intercepting different radius buffers and analyzing the optimal scale characteristics of pollinators in different landscape compositions.Field sampling was conducted from April to May in spring and September to October in autumn in 2017,using three-color trapping methods to sample pollinators in the two study areas.The response of pollinator diversity to landscape heterogeneity and seasonal dynamics of pollinators in different research areas were analyzed at the habitat scale.By analyzing the diversity characteristics and seasonal changes of pollinating insect communities under different landscape heterogeneity levels,the responses of pollinating insect group characteristics to landscape scale were explored.Pearson correlation analysis was used to analyze the correlation of pollinating insect communities,and the 95% confidence coefficient interval and correlation degree(P value)were used to compare the correlation of dominant pollinator communities in different habitats to identify pollinator biodiversity in different habitats.The processing and analysis of landscape data used ARCGIS 10.3 and Fragstats 4.0.The main findings are as follows:(1)In the spring Gongyi study area,18,576 pollinating insects were collected,a total of 10 orders,94families;in autumn,27,167 pollinating insects were captured,a total of 9 orders,88 families.In the spring Minquan research area,a total of 18,518 pollinating insects were captured,divided into 9 orders,84 families.In autumn,18,289 pollinating insects were captured,totaling 8 orders and 81 families.The main pollinating insect functional groups are Diptera,Hymenoptera,Coleoptera,and Lepidoptera;Among them,the dominant group coexisting in the two research areas in spring is Vespidae,Apidea,and in autumn,thegenus Callidum and Calliphoridae.The number of insects caught in farmland habitats is the highest in different seasons.In the farmland habitats of the two springs,the diptera was the most abundant and the number of individuals was the most;the natural forests and plantations in the Gongyi study area had the largest number of Vespidae in the Diptera;plantation of Minquan study area was double.The most common species of the genus Tenthredinidae.In the farmland habitats of both autumns,Syrphidae is the most abundant;The dominant group of Gongyi plantation and natural forest are Mycetophilidae and Mycetophilidae,and Minquan plantation is dominated by Mydaidae.The changes of pollination group in spring and autumn are mainly reflected in Diptera and Hymenoptera.(2)The Gongyi study area with higher landscape heterogeneity maintained a higher level of pollinator diversity.The biodiversity index in spring and autumn showed that the diversity,richness and evenness of pollinators in the Gongyi study area were significantly higher than those in the Minquan research area(P<0.05).However,the Minquan research area in spring is more conducive to the distribution of a larger number of pollinators,of which pollinators are most widely distributed in civil rights farmland;The abundance of pollinating insects in woodland was lower than that in farmland.In the autumn,the species richness of Gongyi plantation was significantly higher than that of Gongyi natural forest.On the landscape scale,the species richness of farmland habitat in Gongyi district was significantly higher than that of civil rights farmland,while Gongyi plantation was significantly higher than forest land of Minquan.(3)From the perspective of landscape index,the landscape heterogeneity level of Gongyi is significantly higher than that of Minquan,and the level of biodiversity changes with the change of landscape scale.At the level of landscape index,patch density index(PD),patch richness index(PR)and Shannon diversity index(SHDI)all showed that Gongyi was greater than Minquan.According to the trend of landscape index,the three indices of CONTAG,PR and SHDI in the two study areas all showed anincrease with the increase of landscape scale,while PD showed a decrease with the increase of landscape scale.However,the four indexes of CONTAG,PD,PR and SHDI in the Minquan research area were significantly smaller than the Gongyi study area.In the Gongyi study area,the correlation between pollinator diversity and landscape index was the most significant at 2000 m,the characteristic scale of 2000 m can be used as the optimal characteristic scale of pollinating insects in Gongyi.The Minquan were on the500 m feature scale,and the pollinator diversity responded most significantly to the landscape,and the characteristic scale of 2000 m can be used as the optimal characteristic scale of pollinating insects in Minquan.(4)There are differences in the indication functions of the main functional groups of pollinators in different habitat types.The main functional groups of pollinators in spring and autumn also have different responses to pollinator communities in habitats.Coleoptera and Lepidoptera were most significantly associated with pollinator community in the Gongyi plantation in autumn(P<0.01).In the Minquan zone,Diptera,Hymenoptera and Lepidoptera showed the most significant correlation with pollinator community in plantations,and the Lepidoptera was still significantly associated with pollinator community in plantations in spring.Regardless of seasonal changes,Lepidoptera can be used as an indicator group in plantations.The impact of landscape heterogeneity on biodiversity is significant,and high levels of landscape complexity and better habitat connectivity can better maintain biodiversity levels.Appropriately increase the connectivity of habitats in landscapes,and the heterogeneity of non-agricultural habitats in agricultural landscapes,adjust the heterogeneity of configuration between different habitats,and rational spatial allocation of landscapes can effectively increase biodiversity.In agricultural production,the protection of semi-natural habitats and the optimization of landscape composition and configuration are importantmeasures to achieve agricultural landscape biodiversity conservation and maintain agricultural landscape ecological functions.At the same time,focus on different insect communities on a small scale,and protect them to maximize the level of biodiversity. |
PDF Full Text Request