Dispersal patterns exhibited by group-living animals play an important role in individual reproductive success and survival, as well as population and social dynamics （Greenwood, 1980; Isbell and van Vuren, 1996; Kap...Dispersal patterns exhibited by group-living animals play an important role in individual reproductive success and survival, as well as population and social dynamics （Greenwood, 1980; Isbell and van Vuren, 1996; Kappeler and van Schaik, 2002）. Dispersing individuals may emigrate voluntarily, or they may be forcibly evicted by other individuals （Pusey and Packer, 1987; Clobert et al. , 2001 ）. One cause of individual dispersal is when an extra-group male compels another male to leave a group of females. This phenomenon has been well documented in primates, especially Old World monkey species （ e.g. Colobus vellerosus ： Saj and Sicotte, 2005 ; Erythrocebus patas ： Ohsawa, 2003 ; Macaca fascicularis ： van Noordwiik and van Schaik, 2001）.展开更多
Arthropod community structure and diversity were investigated in transgenic insect-resistant hybrid poplar 741 field trial plots, which had five isogenic clones with two genes （Bt. toxin [Cry IAc] and arrowhead prote...Arthropod community structure and diversity were investigated in transgenic insect-resistant hybrid poplar 741 field trial plots, which had five isogenic clones with two genes （Bt. toxin [Cry IAc] and arrowhead proteinase inhibitor [API]） in comparison to control plots. Transgenic poplar clones were investigated according to their insect resistance （high and medium resistant clones）, being systematically probed into varying levels with feeding tests before. Investigations were carded out during three years （2002, 2003 and 2005）. The results indicated that among the basal species, transgenic plants in general had lower amounts of phytophagous insects, and an increased quantity of neutral arthropods such as saprophytic and strolling species. Among the top and intermediate species in transgenic variants, the quantity of predatory natural enemies was increased, while the amount of parasitoid ones was slightly reduced. The arthropod community characteristic indices were analyzed from different aspects in the three variants. It was discovered that, not only the characteristic indices of the whole arthropod community, but also the characteristic indices of the sub-communities （such as natural enemy, pest and neutral arthropods） and the functional groups categorized by their feeding patterns, showed a higher diversity and evenness and a lower dominancy concentration indices in the high-resistant and medium-resistant plots compared with the control. Transgenic poplar 741 showed improved ecological effects both in partial and total aspects. It could be concluded that composition and structure of the arthropod community in plots with transgenic insect-resistant poplar were turned to be more reasonable and itsdiversity and stability was enhanced.展开更多
The relationship between body size and stable isotopic signatures of the omnivorous Redfin Culter(C ultrichthys erythropterus),commonly found in East Lake Taihu,was investigated. Previous analyses of C. erythropterus ...The relationship between body size and stable isotopic signatures of the omnivorous Redfin Culter(C ultrichthys erythropterus),commonly found in East Lake Taihu,was investigated. Previous analyses of C. erythropterus stomach contents have shown that this species undergoes a diet switch from being predominantly zooplanktivorous to piscivorous during its life history. This was confirmed by stable carbon isotopic signature(δ 13 C) in this study,in which δ 13 C was positively correlated with both standard length and weight. The importance of littoral-benthic resources in supporting C. erythropterus during its lifespan was also demonstrated using a two-source mixing model,the results of which showed a significant increasing trend in the contribution of littoral-benthic energy. However,the stable nitrogen isotopic signature(δ 15N) exhibited an unusual pattern compared with previous studies. The δ 15 N of C. erythropterus showed no relationship with body size,even though dietary changes were observed. This indicated that δ 15 N alone cannot fully reflect a diet shift in a species and possible variability in isotopic signatures over its life history. This should be considered when using stable isotopic signatures to investigate intra-specific variations and the timing of life-history events,such as estimating the trophic positions of fish species.展开更多
Predation is thought to be one of the main structuring forces in animal communities. However, se- lective predation is often measured on isolated traits in response to a single predatory species, but only rarely are s...Predation is thought to be one of the main structuring forces in animal communities. However, se- lective predation is often measured on isolated traits in response to a single predatory species, but only rarely are selective forces on several traits quantified or even compared between different predators naturally occurring in the same system. In the present study, we therefore measured be- havioral and morphological traits in young-of-the-year Eurasian perch Perca fluviatilis and com- pared their selective values in response to the 2 most common predators, adult perch and pike Esox lucius. Using mixed effects models and model averaging to analyze our data, we quantified and compared the selectivity of the 2 predators on the different morphological and behavioral traits. We found that selection on the behavioral traits was higher than on morphological traits and perch predators preyed overall more selectively than pike predators. Pike tended to positively se- lect shallow bodied and nonvigilant individuals （i.e. individuals not performing predator inspec- tion）. In contrast, perch predators selected mainly for bolder juvenile perch （i.e. individuals spend- ing more time in the open, more active）, which was most important. Our results are to the best of our knowledge the first that analyzed behavioral and morphological adaptations of juvenile perch facing 2 different predation strategies. We found that relative specific predation intensity for the di- vergent traits differed between the predators, providing some additional ideas why juvenile perch display such a high degree of phenotypic plasticity.展开更多
In temperate agroecosystems, avian responses in abundance and distribution to landscape attributes may be exacerbated by the coupling of natural seasons and farming practices. We assessed the sea- sonal roles of field...In temperate agroecosystems, avian responses in abundance and distribution to landscape attributes may be exacerbated by the coupling of natural seasons and farming practices. We assessed the sea- sonal roles of field type, field use in the surroundings, and distance from a field to the nearest woodlot on the abundance of seed-eating birds in a 225,000 km2 study area in the Pampas of central Argentina. During spring-summer and autumn of 2011-2013, we randomly selected 392 fields and used transect samples to collect data on abundance and presence of seed-eating bird species. We recorded a total of 11,579 individuals belonging to 15 seed-eating bird species. We used generalized lineal mixed models to relate bird abundance to field type, field use in the surroundings, and distance to the nearest woodlot. In spring-summer （breeding season） most bird responses were associated with their nesting requirements. Species that build their nests in trees, such as eared doves Zenaida auriculata, picazuro pigeons Patagioenas picazuro, and monk parakeets Myiopsitta monachus, were more abundant in fields closer to woodlots, whereas grassland yellow-finches Sicalis luteola, which nest at areas with tall grasses, were more abundant in fields with livestock use patches in the field surroundings. In au- tumn （non-breeding season）, most bird responses were associated with foraging and refuge needs. The high abundance of eared doves in crop stubbles and the association of pigeons at field surroundings dominated by croplands or at crop stubbles surrounded by livestock use fields revealed the intimate association of these species to sites with high availability of food resources. In addition, both picazuro pigeons and spot-winged pigeons Patagioenas maculosa were associated with woodlots, which provide suitable roosting sites. Our results show that in temperate agroecosystems, the relationships between field characteristics and seed-eating bird abundances vary with season.展开更多
基金funded by Natural Science Foundation of China(No.30770375,No.30570312,No.30630016)Cosmo Oil Eco Card Fund of Japan(2005-2010)Northwest University Doctorate Dissertation of Excellence Funds(07YYB06)
文摘Dispersal patterns exhibited by group-living animals play an important role in individual reproductive success and survival, as well as population and social dynamics （Greenwood, 1980; Isbell and van Vuren, 1996; Kappeler and van Schaik, 2002）. Dispersing individuals may emigrate voluntarily, or they may be forcibly evicted by other individuals （Pusey and Packer, 1987; Clobert et al. , 2001 ）. One cause of individual dispersal is when an extra-group male compels another male to leave a group of females. This phenomenon has been well documented in primates, especially Old World monkey species （ e.g. Colobus vellerosus ： Saj and Sicotte, 2005 ; Erythrocebus patas ： Ohsawa, 2003 ; Macaca fascicularis ： van Noordwiik and van Schaik, 2001）.
文摘Arthropod community structure and diversity were investigated in transgenic insect-resistant hybrid poplar 741 field trial plots, which had five isogenic clones with two genes （Bt. toxin [Cry IAc] and arrowhead proteinase inhibitor [API]） in comparison to control plots. Transgenic poplar clones were investigated according to their insect resistance （high and medium resistant clones）, being systematically probed into varying levels with feeding tests before. Investigations were carded out during three years （2002, 2003 and 2005）. The results indicated that among the basal species, transgenic plants in general had lower amounts of phytophagous insects, and an increased quantity of neutral arthropods such as saprophytic and strolling species. Among the top and intermediate species in transgenic variants, the quantity of predatory natural enemies was increased, while the amount of parasitoid ones was slightly reduced. The arthropod community characteristic indices were analyzed from different aspects in the three variants. It was discovered that, not only the characteristic indices of the whole arthropod community, but also the characteristic indices of the sub-communities （such as natural enemy, pest and neutral arthropods） and the functional groups categorized by their feeding patterns, showed a higher diversity and evenness and a lower dominancy concentration indices in the high-resistant and medium-resistant plots compared with the control. Transgenic poplar 741 showed improved ecological effects both in partial and total aspects. It could be concluded that composition and structure of the arthropod community in plots with transgenic insect-resistant poplar were turned to be more reasonable and itsdiversity and stability was enhanced.
基金Supported by the National Natural Science Foundation of China(No.41206124)the Ph.D Programs Foundation of Ministry of Education of China(No.23104120001)the "Chen Guang" Project(No.10CG52)
文摘The relationship between body size and stable isotopic signatures of the omnivorous Redfin Culter(C ultrichthys erythropterus),commonly found in East Lake Taihu,was investigated. Previous analyses of C. erythropterus stomach contents have shown that this species undergoes a diet switch from being predominantly zooplanktivorous to piscivorous during its life history. This was confirmed by stable carbon isotopic signature(δ 13 C) in this study,in which δ 13 C was positively correlated with both standard length and weight. The importance of littoral-benthic resources in supporting C. erythropterus during its lifespan was also demonstrated using a two-source mixing model,the results of which showed a significant increasing trend in the contribution of littoral-benthic energy. However,the stable nitrogen isotopic signature(δ 15N) exhibited an unusual pattern compared with previous studies. The δ 15 N of C. erythropterus showed no relationship with body size,even though dietary changes were observed. This indicated that δ 15 N alone cannot fully reflect a diet shift in a species and possible variability in isotopic signatures over its life history. This should be considered when using stable isotopic signatures to investigate intra-specific variations and the timing of life-history events,such as estimating the trophic positions of fish species.
文摘Predation is thought to be one of the main structuring forces in animal communities. However, se- lective predation is often measured on isolated traits in response to a single predatory species, but only rarely are selective forces on several traits quantified or even compared between different predators naturally occurring in the same system. In the present study, we therefore measured be- havioral and morphological traits in young-of-the-year Eurasian perch Perca fluviatilis and com- pared their selective values in response to the 2 most common predators, adult perch and pike Esox lucius. Using mixed effects models and model averaging to analyze our data, we quantified and compared the selectivity of the 2 predators on the different morphological and behavioral traits. We found that selection on the behavioral traits was higher than on morphological traits and perch predators preyed overall more selectively than pike predators. Pike tended to positively se- lect shallow bodied and nonvigilant individuals （i.e. individuals not performing predator inspec- tion）. In contrast, perch predators selected mainly for bolder juvenile perch （i.e. individuals spend- ing more time in the open, more active）, which was most important. Our results are to the best of our knowledge the first that analyzed behavioral and morphological adaptations of juvenile perch facing 2 different predation strategies. We found that relative specific predation intensity for the di- vergent traits differed between the predators, providing some additional ideas why juvenile perch display such a high degree of phenotypic plasticity.
文摘In temperate agroecosystems, avian responses in abundance and distribution to landscape attributes may be exacerbated by the coupling of natural seasons and farming practices. We assessed the sea- sonal roles of field type, field use in the surroundings, and distance from a field to the nearest woodlot on the abundance of seed-eating birds in a 225,000 km2 study area in the Pampas of central Argentina. During spring-summer and autumn of 2011-2013, we randomly selected 392 fields and used transect samples to collect data on abundance and presence of seed-eating bird species. We recorded a total of 11,579 individuals belonging to 15 seed-eating bird species. We used generalized lineal mixed models to relate bird abundance to field type, field use in the surroundings, and distance to the nearest woodlot. In spring-summer （breeding season） most bird responses were associated with their nesting requirements. Species that build their nests in trees, such as eared doves Zenaida auriculata, picazuro pigeons Patagioenas picazuro, and monk parakeets Myiopsitta monachus, were more abundant in fields closer to woodlots, whereas grassland yellow-finches Sicalis luteola, which nest at areas with tall grasses, were more abundant in fields with livestock use patches in the field surroundings. In au- tumn （non-breeding season）, most bird responses were associated with foraging and refuge needs. The high abundance of eared doves in crop stubbles and the association of pigeons at field surroundings dominated by croplands or at crop stubbles surrounded by livestock use fields revealed the intimate association of these species to sites with high availability of food resources. In addition, both picazuro pigeons and spot-winged pigeons Patagioenas maculosa were associated with woodlots, which provide suitable roosting sites. Our results show that in temperate agroecosystems, the relationships between field characteristics and seed-eating bird abundances vary with season.
