The Effects Of Non-random Species Loss On Arthropod Diversity In An Alpine Meadow On The Tibetan Plateau

The loss of global biodiversity has brought about some irreversible impacts on human environment.In recent years,due to climate change,overgrazing and other factors,the alpine meadow community biodiversity loss and local grassland degradation,which has a certain impact on the stability and function of grassland ecosystem.Species loss in natural grassland communities occurs mostly through non-random circumstances.Based on the above reasons,in the alpine meadow in the eastern margin of Qinghai-Tibet Plateau,this study has conducted a systematic series of artificial removing experiments according to different height and plant functional groups(tall grasses and sedges,tall forbs,medium forbs and short forbs)in the past 10 years.Through the influence of non-random species loss,in order to understand the effects on plant diversity and arthropod diversity and ecosystem stability in natural communities.Affecting plant communities from the loss of original plant species,plant species diversity,aboveground biomass,and functional traits(plant height and coverage)are included.Changes in plant species can further affect the diversity of arthropods(flower-visiting insects and surface arthropods)and the composition of arthropod species.This study is conducive to providing scientific theoretical basis for the arthropod-mediated grassland ecosystem restoration in the alpine meadow ecosystem.The main conclusions of this study are as follows:(1)The removal of different plant functional groups changed plant community composition and functional traits in alpine grassland.All treatments were compared with natural controls,different from the removal of tall forbs,medium forbs and tall grasses and sedges functional groups,the removal of short forbs significantly reduced the species richness,biomass and weighted height of the plant community,that is,the compensation effect of the grassland community was minimal.The weighted height of plant community also decreased significantly after medium forbs were removed.After medium forbs functional groups and tall grasses and sedges functional groups were removed,the weighted height of flowering plants decreased significantly,indicating that plant species in the next layer would not compete for height growth after getting sufficient light resources,which may be reflected in flower size.(2)The removal of plant functional groups of different heights significantly affected the pollination network structure,and the effect on functional groups was different.The diversity of diptera pollinators at community level was significantly increased after the removal of tall grasses and sedges functional groups.After all treatments were compared with the control,the Simpson diversity index of total pollinators was significantly reduced after mediun forbs,which was different from other functional group removal treatments.At the same time,the removal of medium forbs significantly reduced the stability of pollination network.It may be that medium forbs contain dominant species of flowering plants,and these species play a key role in maintaining the stability of pollination network structure.(3)The removal of different plant functional groups in alpine meadow had different effects on the surface arthropod community and its functional groups.After the removal of tall and medium forbs,the species and number of surface arthropods increased significantly,which may be related to the fact that forbs groups are not favored by surface arthropods,so it is consistent with the result of resource concentration hypothesis.Compared with tall forbs and medium forbs.The species and number of surface arthropods increased most significantly after the removal of short forbs,maybe because the short forbs are closest to the surface,the increase of surface space after the removal of short forbs is more conducive to the increase of the mobility of surface arthropods.Compared with forbs groups,the surface arthropod community in the alpine meadow was more dependent on tall grasses and sedges,indicating that the Shannon diversity of phytophagans decreased while that of predators decreased significantly after the removal of tall grasses and sedges.Treatment and plant biomass were the main factors affecting the number and species of surface arthropods.At the same time,the microenvironment under different treatments may also affect the number of surface arthropods.The above results show that the alpine meadow of Qinghai-Tibet Plateau.With short forbs loss,the grassland community had the lowest compensation effect and was more likely to increase the mobility of surface arthropods.Medium forbs play a key role in maintaining the diversity of pollinator and the stability of pollinate networks.Our results also demonstrate that surface arthropods are more dependent on grasses and sedges than on forbs.At the same time,our results also verified that the removal of tall grasses and sedges was more conducive to the interaction between pollinators and flowering plants.This study provides a new insight into the mechanism of non-random plant species diversity loss on arthropod diversity.