Summary Species coexistence can be promoted by both equalizing mechanisms that increase fitness equivalence among species and stabilizing mechanisms that decrease niche overlap among species. Strength of the coexistence mechanisms can be altered by evolution. In particular, populations evolved in sympatry may show niche divergence due to competition‐mediated selection, whereas populations evolved in allopatry have a chance to become ecologically equivalent competitors which, on secondary contacts, may form ‘neutral communities’. We addressed how evolution may change ecological mechanisms of coexistence with experimental microcosms of Escherichia coli strains that reproduce asexually and can be considered as analogues of species. We obtained five pairs of bacterial strains, within each of which the two strains could coexist stably. We then allowed the bacterial strains to evolve in a chemically defined nutrient medium for ˜1100 generations, under sympatric (in two‐strain mixtures) or allopatric scenarios (in monocultures). The strength of coexistence mechanisms was assessed based on reciprocal invasion assays and measurements of environmental carrying capacity. Our data confirmed that coexistence could be weaken by either fitness difference or niche overlap among competitors. In allopatrically evolved strain pairs, fitness difference among competitors became larger or unchanged; and the magnitude of niche overlap often showed an increase rather than a decline. Sympatrically evolved competitors showed no consistent changing trend in the strength of the coexistence mechanisms. Overall, sympatrically evolved competitor pairs did not differ from allopatrically evolved ones in the magnitude of fitness difference, but had lower levels of niche overlap. The results are consistent with the ‘character displacement’ view that allopatric populations of competing species occupy more similar niche space compared with sympatric populations. However, the pattern observed here resulted from allopatrically evolved competitors showing niche convergence, but not sympatrically evolved competitors consistently showing further niche divergence. The results also suggest that convergent evolution in allopatry followed by secondary contacts is an unlikely mechanism for the origin of ‘neutral communities’.
In order to promote multi-directional exchanges among environmental management departments, enterprises and public to improve capacity of environmental information disclosure, environmental governance open innovation model based on environmental information disclosure should be established to take advantage of the public pressures of environmental governance to promote improvement of environmental behavior of enterprises and government departments. Environmental governance open innovation model is based on the public access to environmental information, thereby establishing a comprehensive environmental information platform is essential. By taking advantage of cloud computing technology features of ultra-large-scale, high scalability and on-demand services, a cloud computing based environment information platform will be established to meet needs of public access to environmental information and environmental participation. The platform can customize different services for different users, and promote the development of environmental governance mode to achieve the improvement of environmental quality.
The role that visual discriminative ability plays among giant pandas in social communication and individual discrimination has received less attention than olfactory and auditory modalities. Here, we used an eye-tracker technology to investigate pupil fixation patterns for eight captive male giant pandas Ailuropoda melanoleuca. We paired images (N = 26) of conspecifics against: 1) sympatric predators (gray wolves, tigers), and non-threatening sympatric species (golden pheasant, golden snub-nosed monkey, takin, red panda), 2) conspecifics with atypical fur coloration (albino, brown), and 3) zookeepers/non-zookeepers wearing either work uniform or plain clothing. For each session, we tracked the panda’s pupil movements and measured pupil first fixation point (FFP), fixation latency, total fixation count (TFC) and duration (TFD) of attention to each image. Overall, pandas exhibited similar attention (FFPs and TFCs) to images of predators and non-threatening sympatric species. Images of golden pheasant, snub-nosed monkey and tiger received less attention (TFD) than images of conspecifics, whereas images of takin and red panda received more attention, suggesting a greater alertness to habitat or food competitors than to potential predators. Pandas’ TFCs were greater for images of black-white conspecifics than for albino or brown phenotypes, implying that familiar color elicited more interest. Pandas reacted differently to images of men vs women. For images of women only, pandas gave more attention (TFC) to familiar combinations (uniformed zookeepers and plain-clothed non-zookeepers), consistent with the familiarity hypothesis. That pandas can use visual perception to discriminate intra-specifically and inter-specifically, including details of human appearance, has applications for panda conservation and captive husbandry.
Infant call structure should have evolved to elicit maximum maternal attention and investment. Neonates of giant pandas produce three types of vocalizations reported to be vitally important in the context of mother–infant communications. However, how cubs, 0–15 days old, communicate with their mothers to elicit maternal care remains unknown. We analyzed 12 different call parameters of 3475 squawks, 1355 squalls, and 491 croaks from 11 captive giant panda (Ailuropoda melanoleuca) neonates from age 0 to 15 days. In playback experiments, we also tested whether mothers could detect ultrasound. Our results show that neonates use broadband calls with ultrasonic frequencies up to 65 kHz to convey information about their physiological needs and to attract maternal care. In playback experiments, we tested if mothers reacted differently to broadband calls (BBC) than to artificially altered calls that included only frequencies <20 kHz (AUDC) or calls that included only frequencies >20 kHz (USC). Playback confirmed that, although adult females responded significantly less often to USC, BBC than to or AUDC, they could detect USC, BBC and generally made appropriate behavioral responses, indicating a potential benefit for neonates to utilize ultrasonic and broadband frequencies. Our findings provide a new insight into mother–infant communication in giant pandas and will be helpful for reducing the mortality of cubs, younger than 1 month old, in captivity.
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