| Seed dispersal by ants(myrmecochory)is an important way of plant seed dispersal,widely distributed in a variety of ecosystems.During seeds dispersal by ants,ants benefit by gaining nutrition and energy from consuming a lipid-rich appendage on the seed(oleosome)and in return provide seed dispersal service to the plant,the interaction between both sides can get benefits.There are many factors affect seed dispersal,including biotic factors(such as phenology,characteristics of diaspore,characteristics of ants etc.)and abiotic factors(such as light,temperature,rainfall,flood,etc.).Previous studies have shown that habitat change will influence seed dispersal through affect the richness and the abundance of ants,and also affect the rates of seed dispersal by ants.Former research on the impact of habitat change for myrmecochory most concentrated in a larger scale habitat change or anthropogenic disturbance for ant community composition,only a few of research pay attention to small scale habitat heterogeneity for ant-mediated seed dispersal,especially for the plants which distributed in patch pattern,we didn't known whether the change of plant abundance and density will affect the ant community composition,the abundance and species of disperser,and future affect seed dispersal by ants.Field experiments were conducted with four species of plants which are belong to Corydalis DC.(Papaveraceae),including C.hemsleyana Franch.ex Prain,C.acuminata Franch.,C.sheareri Moore,C.giraldii Fedde to explore the ant community composition and the abundance of ants in the study sites,and compare the rates of seed dispersal by ants,in order to offer some information for further study on population maintian and spread of the plants which is seed dispersal by ants.The main findings are as follows:1.In forest interior study site of C.hemsleyana,5 ant species were captured,the ants of Formica fusca,Pheidole sp.1,Lasius sp.2 didn't removaling seed,only 2 species of ants are dispersers,including Myrmica sp.l and Paratrechina vividula,the dominant disperser was Myrmica sp.1 accounted for about 81.7%of the total seeds removed;the study site of Roadsite 1,7 ant species were captured,the ants of Paratrechina sp.2 didn't removaling seed,6 species of dispersers,including Lasius alienus,Paratrechina vividula,Formica fusca,Pheidole sp.1,Myrmica sp.1 and Lasius sp.2,the dominant disperser were Lasius alienus and Paratrechina vividula accounted for about 39.25%and 27.15%of the total seeds removed respectively;the study site of Roadsite 2,4 ant species were captured,the ants of Myrmica sp.1 didn't removing seed,3 species of dispersers,including Lasius alienus,Pheidole sp.1 and Paratrechina sp.2,the dominant disperser was Lasius alienus and Pheidole sp.1,accounted for about 42.92%and 51.60%of the total seeds removed respectively.Statistical analysis shown that:among the 3 study sites,ant community composition and the species of dominant dispersers the relative contributions of seed dispersed were changed,abundance of removing ant were significantly different in disperser abundance(P<0.05),abundance of removing ant in forest interior site was significantly lower than the site of roadside 2(P<0.05).Rates of seeds dispersal by ants also significantly different(P<0.05).The rate of seed dispersal by ants didn't shown a significant difference between two roadsite study sites which have different plant abundance(P>0.05),in roadsite 2 the rate of seed dispersal by ants was significantly higher than forest interior study site(P<0.05).2.In forest interior study site of C.acuminata,7 ant species were captured,the ants of Myrmica sp.l and Paratrechina sp.3 didn't removaling seed,5 species of dispersers,including Formica sp.l and Pheidole sp.1,Formica fusca,Lasius alienus,Paratrechina vividula,the dominant disperser was Myrmica sp.1 accounted for about 81.7%of the total seeds removed;the study site of forest interior 2,5 ant species were captured,the ants of Formica fusca,Pheidole sp.1 and Paratrechina vividula didn't removaling seed,2 species of dispersers,including Formica sp.1 and Lasius alienus,the dominant disperser was Formica sp.l accounted for about 81.6%of the total seeds removed.In the study site of Roadsite 1,5 ant species were captured,the ants of Odontomachus sp.and Paratrechina vividula didn't removaling seed,3 species of dispersers,including Formica sp.1,Lasius alienus and Formica fusca,the dominant disperser was Myrmica sp.1 and Lasius alienus.accounted for about 66.20%and 30.77%of the total seeds removed respectively.In the study site of Roadsite 2,3 ant species were captured,all of dispersers,including Formica fusca,Formica sp.l and Lasius alienus,accounted for about 49.82%,27.90%and 22.28%of the total seeds removed respectively.Statistical analysis shown that:among the 4 study sites,ant community composition and the species of dominant dispersers the relative contributions of seed dispersed were changed,abundance of removing ant were significantly different in disperser abundance(P<0.05),but it didn't have significantly difference for each other.The rates of seeds dispersal by ants also significantly different(P<0.05).The forest interior 2 which have less plant abundance the rate of seed dispersal by ants was significantly higher than forest interior 1 study site which have more plant abundance(P<0.05),the rate of seed dispersal by ants didn't shown a significant difference between two roadsite study sites which have different plant abundance of(P>0.05),the rate of seed dispersal by ants in roadsite lwas significantly higher than forest interior 2 study site,both have similar plant abundance(P<0.05).3.In forest interior study site of C.sheareri,4 ant species were captured,the ants of Formica sp.1,Pheidole sp.l and Paratrechina vividula didn't removaling seed,only Myrmica sp.1 was disperser,accounted for about 100.00%of the total seeds removed;the study site of Roadsite 1,6 ant species were captured,the ants of Paratrechina sp.2 and Paratrechina vividula didn't removaling seed,4 species of dispersers,including Lasius alienus,Pheidole sp.1,Formica sp.1 and Myrmica sp.1,the dominant disperser was Lasius alienus and Pheidole sp.1,accounted for about 52.07%and 33.88%of the total seeds removed respectively.the study site of Roadsite 2,4 ant species were captured,the ants of Odontomachus sp.and Paratrechina vividula didn't removaling seed,2 species of dispersers,including Pheidole sp.1 and Lasius alienus,the dominant disperser was Pheidole sp.1,accounted for about 91.14%of the total seeds removed.Statistical analysis shown that:among the 3 study sites,ant community composition and the species of dominant dispersers the relative contributions of seed dispersed were changed,abundance of removing ant idn't shown a significantly different(P>0.05).The rate of seed dispersal by ants in two roadsite study sites were significantly higher than forest interior study site(P<0.05),the rate of seed dispersal by ants didn't shown a significant difference between two roadsite study sites(P>0.05).4.According to the number of individuals in 1m2,the study sites of C.giraldii divide into high density(5.400 ± 0.812 individuals/m2),medium density(3.000 ± 0.362 individuals/m2),low density(1.200 ± 0.490 individuals s/m2)(n=5)and none C.giraldii distribution,results show that:(1)A total of 9 ant species were captured in four different density study sites including Pheidole nietneri,Myrmica ruginodis,Lasius sp.1,Paratrechina sp.1,Aphaenogaste smythiesii,Lasius alienus,Formica fusca,Terramorium caespitum and Odontomachus sp.The study site with high density of plants,7 ant species were captured,only 2 species of dispersers,including Aphaenogaste smythiesii and Lasius alienusa,the dominant disperser was Aphaenogaste smythiesii,accounted for about 88.89%of the total seeds removed;medium density study site,9 ant species were captured,2 species of dispersers,including L Aphaenogaste smythiesii and asius alienusa,the dominant disperser was asius alienusa,accounted for about 81.82%of the total seeds removed;low density study site,7 ant species were captured,5 species of dispersers,including Paratrechina sp.1,Aphaenogaste smytythiesii;Lasius alienusa,Formica fusca,Terramorium caespitum,the dominant disperser was Paratrechina sp.1,accounted for about 55.41%of the total seeds removed;none C.giraldii distribut study site,8 ant species were captured,only 1 species of dispersers,Aphaenogaste smythiesii accounted for about 100.00%of the total seeds removed.Statistical analysis shown that:among the 4 study sites,the species of ants was similar common,the species of dominant dispersers the relative contributions of seed dispersed were changed,abundance of removing ant were significantly different(P<0.05),Ant abundance in low density site was significantly higher than other study sites(P<0.05),didn't shown significant differences among other study sites.The rates of seeds dispersal.by ants also significantly different(P<0.05),In low density site the rate of seed dispersal by ants was significantly higher than high and medium density study site(P<0.05),the rate of seed dispersal by ants in the site of none C.giraldii distribution was lower than low density,and higher than high density and medium density site,but didn't significant.Our research showed that difference of habitat,plant abundance density will influence the ant community composition and the species of dispersers for conspecies,but for diffenent species these differences may have inconsistent effect for disperser abundance,it may be related to plant traits.The results may provide information for the future study of ants-plant(seed)mutualism interation and its effect factors,also provide reference for further research on population spatial distribution pattern and its colonization of myrmecochore. |
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