The Black-necked Grebe (Podiceps nigricollis) is a national second-class protected bird in China. In the present study, the nest sites of the Black-necked Grebe in Ordos Relict Gull National Nature Reserve were investigated from June to July, 2022 to protect them. A principal component analysis method and logistics regression model were used to analyze the relationship between nest site selection and 8 habitat factors, including concealment of the nest, plant coverage in the area, and the abundance of invertebrates surrounding the nest site. The results revealed that the black-necked grebe mainly nested in shallow water areas (water depth was 10.56 cm) with a higher degree of concealment that were not affected by the prevailing wind. The main nest materials were Zannichelia palustris, Spirogyra communs, animal feathers and plant branches. The concealment, plant coverage and invertebrate abundance of the black-necked grebe nest site quadrat (n=20) were significantly higher than those of the control quadrat (n=20, p<0.01). There was a significant difference between the nested and control quadrat on the factors of whether they were affected by the prevailing wind (χ²=26.302, df=1, p<0.001). These results indicated that plant coverage, invertebrate abundance, concealment of the nest, and whether affected by the prevailing wind were the main factors affecting the nesting of black-necked grebe. In order to better protect the breeding population of black necked grebe in the Ordos Relict Gull National Nature Reserve, it is recommended to continuously replenish water to maintain the stability of the water environment and the coverage of aquatic plants in the reserve, and to conduct long-term monitoring of the replenishment source to ensure water quality. Increasing the abundance of invertebrates in the water to provide sufficient food for black necked grebes and other breeding birds. In addition, plants should be reasonably planted on the south bank of the island in the center of the lake, and construct a three sided earth dam enclosure in the area where black necked grebes nest to improve the concealment of the nest and reduce the impact of the prevailing wind on them.

The wetlands are the habitats and the stopover sites of the waterfowls, the fishes in the wetlands are the important food basis of the waterfowls. Jilin Momoge National Nature Reserve is an important resting place for the migration of rare and endangered birds, such as Grus leucogeranus and Ciconia boyciana, it was included in the list of international important wetlands in 2013. In recent years, the suitability of the fish habitat in this area has weakened, the proliferation capacity of fish resources has declined, and the suitability of wetlands as waterfowl habitats and stopover sites has decreased. In order to increase the fish resources in the wetlands and improve the suitability of the wetlands as waterfowl habitat and stopover site, from 2016 to 2017, the natural habitats of fish in the shallow water area near shore and floodplain area of Nenjiang River were repaired by the method of wetland hydrology and substrate restoration. Before and after the restoration of fish habitats, fish samples were collected and investigated in September 2015 and November 2017 to September 2021, respectively. The composition and structural characteristics of fish communities before and after the restoration of fish habitats were studied, and the restoration effect of fish habitat was evaluated. The results showed that compared with the natural habitats of fish, the number of fish species in the restored habitat increased significantly, while the relative population biomass and relative population number of economic fish decreased by 16.02% and 39.98%, respectively. The relative population biomass and relative population number of small non-economic fish increased by 1.43 times and 63.54%, respectively, compared with the original habitat. The existing resources of fish, the average annual fish resources and the average annual fish distribution density increased significantly. The values of Simpson diversity index and Pielou evenness index of the fish community in the restored habitat were 31.98% and 34.42% lower than those in the natural habitat, respectively. The wetland hydrology and substrate restoration methods adopted by improved the suitability of the restored habitat for fish, promoted the natural proliferation of fish resources and the self-development of the population, and realized the sustainability of the functions of the shallow water area near shore and the floodplain area of the Nenjiang River as the habitats and migration stopover sites of waterfowls, which made up for the defects of poor suitability of the natural habitats, low natural proliferation ability of fish and unsustainable population development. This restoration method could provide reference for the restoration of fish habitats in the nature reserves for the wetlands in Songnen Plain.

In order to understand the law of embryonic development of Leuciscus idus, the wild population was used as the parent, and the fertilized eggs were obtained by artificial insemination. The time sequence of embryonic development and the characteristics of each stage were observed, described, recorded and analyzed in detail. The results showed that under the condition of 13.34 ℃ water temperature, the embryos of Leuciscus idus underwent 234 h and 20 min of hatching, requiring the total accumulated temperature of 3 136.36 ℃·h. The embryonic development of Leuciscus idus has undergone 7 stages (further subdivided into 26 stages), including germinal, cleavage, blastocyst, gastrula, neural, organ formation and incubation stages. Among them, the accumulated temperature required in incubation stage was the most, followed by the organ formation stage, and the accumulated temperature needed in the blastocyst, cleavage, thneural, gastrula stage, and the germinal stage decreased in turn; after 96 h, the eye, digestive tract, gill lid and other organs of larvae in hatching were fully formed, and the mouth had been opened for feeding; however, at this time, it was the mode of mixed absorption of endogenous and exogenous nutrients, until the 5th day, the yolk sac was absorbed, and completely converted into exogenous nutrient absorption mode. In the early growth and development process, Leuciscus idus could enhance their adaptability to the environment and improve the survival rate through a series of physiological changes, such as the rapid transformation of food sources and rapid development of organs. Therefore, in-depth research on the biological characteristics of Leuciscus idus during their early development stage of great significance for improving the survival rate of its seeds and further carrying out the artificial breeding of this species in the future.

From May to September 2021, 5 field surveys were conducted on the vascular plants Inner Mongolia Honghuaerji Yiminhe National Wetland Park, using the line sampling method and quadrat method, and the composition characteristics of vascular plants and the flora of families, genera, and species in the wetland park were analyzed, aiming to lay a theoretical foundation for plant restoration, biodiversity protection, and rational utilization of vascular plant resources in the park. The research results indicated that 445 species of vascular plants belonging to 241 genera and 63 families were recorded in the wetland park during the survey period; the numbers of species in Asteraceae, Poaceae, Rosaceae, Ranunculaceae, and Fabaceae were 78 species, 47 species, 34 species, 29 species, and 22 species, respectively, accounting for 47.19% of the total species in the wetland park; the species numbers of Artemisia, Potentilla, and Carex rank among the top 3 in 241 genera, with 15 species, 12 species, and 10 species respectively; the 155 genera were the genera with single species, accounting for 64.32% of the total number of genera; 63 families belong to 5 distribution zone types and 3 forms, 241 genera belong to 12 distribution zone types and 8 forms, 445 genera belong to 8 distribution zone types and 20 forms. The flora of families, genera, and species were the most in temperate zone, especially about the flora of genera, which account for 94.30% of the non world distribution genera; most of the flora in the area were young floristic elements, without endemic elements.