Background:The abundance of insects has decreased considerably during recent decades,resulting in current abundance showing 70-80%reductions in more than 15 studies across temperate climate zones.Dramatic reduc-tions ...Background:The abundance of insects has decreased considerably during recent decades,resulting in current abundance showing 70-80%reductions in more than 15 studies across temperate climate zones.Dramatic reduc-tions in the abundance of insects are likely to have consequences for other taxa at higher trophic levels such as preda-tors and parasites.Pesticides,fertilizers and agricultural land use are likely candidates accounting for such reductions in the abundance of insects.Methods:Here we surveyed the abundance of flying insects,and the reduction in the abundance of insects as a consequence of intensive reduction in agricultural practice linked to fertilizer use and pesticide use.Finally we dem-onstrated consistency in abundance of birds among study sites.Results:We demonstrated that the use of fertilizers and pesticides had reduced the abundance of insects,with consequences for the abundance of insectivorous bird species such as Barn Swallows(Hirundo rustica),House Martins(Delichon urbicum)and Swifts(Apus apus).Juvenile Barn Swallows were negatively affected by the reduced abundance of insects and hence the reproductive success of insectivorous bird species.These effects imply that the abundance of insects could be reduced by the availability of insect food.Conclusions:These effects of intensive agriculture on insect food abundance are likely to have negative impacts on populations of insects and their avian predators.This hypothesis was validated by a reduction in the abundance of insects,linked to an increase in the abundance of fertilizers and a general change in farming practice.展开更多
Assemblages of forest insects across two high mountains （Mt. Hallasan： JJ and Mt. Jirisan： JR） in South Korea were compared by collecting insects using an ultraviolet light trap at 20 sites （200-1700 m elevation ...Assemblages of forest insects across two high mountains （Mt. Hallasan： JJ and Mt. Jirisan： JR） in South Korea were compared by collecting insects using an ultraviolet light trap at 20 sites （200-1700 m elevation ranges） from May to October 2013. A total of 2960 individuals, representing 481 species of 10 orders, were collected on JJ, compared with 7080 individuals representing 769 species of 14 orders on JR. The estimated number of species on JJ was 667 compared with 952 on JR. The differentiation among habitats （[3-diversity） was higher on JJ （4.95） than JR （4.33） because of the island characteris- tics of JJ. Six insect orders （Lepidoptera, Coleoptera, Diptera, Hymenoptera, Hemiptera and Trichoptera） were dominant on both mountains, suggesting that the light trap captures represented well the insect fauna and is an effective method for investigating forest insect diversity. We concluded that forest insect assemblages on mountains are mainly affected by the elevation and the dominant forest in each elevation. In addition, the insect fauna on each mountain was differentiated by the habitat, which could be correlated with geological history.展开更多
Common pastures were once the dominant type of land use in many Euro-pean regions.However,during the past 150 years,they have declined dramatically.Recent studies have shown that they are hotspots for rare plant,butte...Common pastures were once the dominant type of land use in many Euro-pean regions.However,during the past 150 years,they have declined dramatically.Recent studies have shown that they are hotspots for rare plant,butterfly,and bird species in the study area,the Bavarian pre-Alps(southern Germany).However,studies on the value of these pastures for Orthoptera(hereinafter termed"grasshoppers")have been scarce.Here,we studied the effects of traditional summer grazing in common pastures on grasshopper assemblages.Our study revealed that grasshopper species richness did not differ between common pastures(n=57)and controls(n=57).By contrast,density of all and of threat-ened species varied between common pastures and controls in all plots and within the two vegetation types with the highest grasshopper abundance,grasslands on mineral soil and fens.Two threatened species,Pseudochorthippus montanus and Stethophyma grossum,were identified as indicators for common pastures;controls had no indicative species.Traditional low-intensity grazing in common pastures has resulted in open and heteroge-neous swards with some bare ground,a low cover of litter and an intermediate vegetation height favouring high densities of grasshopper species in general and threatened species in particular.This is especially true for the two most productive vegetation types,grasslands on mineral soil and fens.To promote biodiversity in general and grasshopper densities in particular,we recommend maintaining traditional cattle grazing(stocking capacities:0.5-2.0 livestock units/ha)in common pastures.Where possible,this grazing regime should also be introduced in the surrounding landscape.展开更多
基金supported by the Latvian Council of Science (grants lzp-2018/2-00057 and lzp-2020/2-0271)supported by the National Natural Science Foundation of China (Grant Nos. 31772453 and 31970427)
文摘Background:The abundance of insects has decreased considerably during recent decades,resulting in current abundance showing 70-80%reductions in more than 15 studies across temperate climate zones.Dramatic reduc-tions in the abundance of insects are likely to have consequences for other taxa at higher trophic levels such as preda-tors and parasites.Pesticides,fertilizers and agricultural land use are likely candidates accounting for such reductions in the abundance of insects.Methods:Here we surveyed the abundance of flying insects,and the reduction in the abundance of insects as a consequence of intensive reduction in agricultural practice linked to fertilizer use and pesticide use.Finally we dem-onstrated consistency in abundance of birds among study sites.Results:We demonstrated that the use of fertilizers and pesticides had reduced the abundance of insects,with consequences for the abundance of insectivorous bird species such as Barn Swallows(Hirundo rustica),House Martins(Delichon urbicum)and Swifts(Apus apus).Juvenile Barn Swallows were negatively affected by the reduced abundance of insects and hence the reproductive success of insectivorous bird species.These effects imply that the abundance of insects could be reduced by the availability of insect food.Conclusions:These effects of intensive agriculture on insect food abundance are likely to have negative impacts on populations of insects and their avian predators.This hypothesis was validated by a reduction in the abundance of insects,linked to an increase in the abundance of fertilizers and a general change in farming practice.
基金supported from the Korea Research Foundation grant(KRF-2012R1A2A2A01003910)
文摘Assemblages of forest insects across two high mountains （Mt. Hallasan： JJ and Mt. Jirisan： JR） in South Korea were compared by collecting insects using an ultraviolet light trap at 20 sites （200-1700 m elevation ranges） from May to October 2013. A total of 2960 individuals, representing 481 species of 10 orders, were collected on JJ, compared with 7080 individuals representing 769 species of 14 orders on JR. The estimated number of species on JJ was 667 compared with 952 on JR. The differentiation among habitats （[3-diversity） was higher on JJ （4.95） than JR （4.33） because of the island characteris- tics of JJ. Six insect orders （Lepidoptera, Coleoptera, Diptera, Hymenoptera, Hemiptera and Trichoptera） were dominant on both mountains, suggesting that the light trap captures represented well the insect fauna and is an effective method for investigating forest insect diversity. We concluded that forest insect assemblages on mountains are mainly affected by the elevation and the dominant forest in each elevation. In addition, the insect fauna on each mountain was differentiated by the habitat, which could be correlated with geological history.
文摘Common pastures were once the dominant type of land use in many Euro-pean regions.However,during the past 150 years,they have declined dramatically.Recent studies have shown that they are hotspots for rare plant,butterfly,and bird species in the study area,the Bavarian pre-Alps(southern Germany).However,studies on the value of these pastures for Orthoptera(hereinafter termed"grasshoppers")have been scarce.Here,we studied the effects of traditional summer grazing in common pastures on grasshopper assemblages.Our study revealed that grasshopper species richness did not differ between common pastures(n=57)and controls(n=57).By contrast,density of all and of threat-ened species varied between common pastures and controls in all plots and within the two vegetation types with the highest grasshopper abundance,grasslands on mineral soil and fens.Two threatened species,Pseudochorthippus montanus and Stethophyma grossum,were identified as indicators for common pastures;controls had no indicative species.Traditional low-intensity grazing in common pastures has resulted in open and heteroge-neous swards with some bare ground,a low cover of litter and an intermediate vegetation height favouring high densities of grasshopper species in general and threatened species in particular.This is especially true for the two most productive vegetation types,grasslands on mineral soil and fens.To promote biodiversity in general and grasshopper densities in particular,we recommend maintaining traditional cattle grazing(stocking capacities:0.5-2.0 livestock units/ha)in common pastures.Where possible,this grazing regime should also be introduced in the surrounding landscape.
