Crane Habitat Research Articles

Using movement ecology to evaluate the effectiveness of multiple human-wildlife conflict management practices

Human-wildlife conflicts are universally growing, threatening sustainable coexistence and demanding increasing conservation efforts. While such conflicts are commonly tackled by combining different management practices, how each component contributes to management effectiveness usually remains unclear. This challenge can be addressed by integrating individual-based movement ecology with detailed information on the variety of management practices applied. Using a high-resolution movement dataset of common cranes (Grus grus) wintering at the agricultural landscape of the Hula Valley (Israel), we assessed their individual-level responses to three conflict management activities – intensive scaring, allocation of refuge areas and diversionary feeding – quantified in space and time throughout the wintering period. We found that diversionary feeding combined with active scaring reduced the cranes' core activity area and led to a significant shift in habitat preference. Low refuge area availability combined with low intensity diversionary feeding required compensation by higher scaring efforts. However, even intensive feeding was insufficient to prevent cranes from foraging on sensitive crops when refuge fields were highly limited. While most cranes heavily relied on the feeding station, a smaller group consistently avoided it and relied on refuge areas and sensitive crops despite scaring efforts. To achieve a more balanced management plan in our case study, provisioning of diversionary food should be much lower, and refuge areas should be designated based on crane habitat selection rather than solely on residual crops. Generally, we stress that quantitative behavioral analysis of target species that incorporates sub-populations with consistent behavioral variation, is important for effective combination of multiple management practices.

Habitat changes in the most important stopover sites for the endangered red-crowned crane in China: a large-scale study.

The red-crowned crane (Grus japonensis) is an endangered bird species that has been listed as one of the Class I National Key Protected Wild Animals of China. This study analyzed the habitat changes in the two most important stopover sites for red-crowned crane (Liao River Estuary and Yellow River Delta National Nature Reserves) from 2000 to 2015. The results showed that the landscape patterns of the important stopover sites of red-crowned crane changed obviously and the potential suitable habitat area (tidal flats and marshland) for the red-crowned crane decreased by 183.3 km2, while the area of human activities (including aquaculture waterbodies, farmland and artificial facilities) increased by 140.3 km2. Landscape fragmentation intensified, which could has negative impacts on the survival of the red-crowned crane during migration. A comparative study confirmed that the reduction in marshlands and increasing landscape fragmentation caused by human activities were the main threats in the Liao River Estuary National Nature Reserve, while human activities and natural factors (such as channel flow, rainfall, and sediment discharge) were the jointly driving factors for the reduction in suitable habitats for red-crowned cranes in the Yellow River Delta National Nature Reserve. We suggest there are some loopholes in the management of the two nature reserves, which need to be strengthened urgently in China.

Influences of submerged plant collapse on diet composition, breadth, and overlap among four crane species at Poyang Lake, China

BackgroundInterannual variation in resource abundance has become more unpredictable, and food shortages have increasingly occurred in the recent decades. However, compared to seasonal fluctuations in resource abundance, the influences of interannual variation in resource abundance on the dietary niches of consumers remain poorly understood. Poyang Lake, China, is a very important wintering ground for the globally endangered Siberian Crane (Leucogeranus leucogeranus), White-naped Crane (Grus vipio), and Hooded Crane (G. monacha), as well as the non-endangered Eurasian Crane (G. grus). Tubers of Vallisneria spp., the dominant submerged macrophytes at Poyang Lake, is an important food for cranes. Nevertheless, submerged macrophytes have experienced serious degradation recently. In this study, we used metabarcoding technology to explore the consequences of Vallisneria tuber collapse on the diet compositions, breadths, and overlaps of the four crane species based on fecal samples collected in winter 2017 (a year with tuber collapse) and winter 2018 (a year with high tuber abundance).ResultsCompared to previous studies, our study elucidates crane diets in an unprecedented level of detail. Vallisneria tubers was confirmed as an important food source of cranes. Surprisingly, the grassland plant Polygonum criopolitanum was also found to be an important food source in the feces of cranes. Agricultural fields were important foraging sites for Siberian Cranes, White-naped Cranes, and Hooded Cranes, providing foods that allowed them to survive in winters with natural food shortages. However, the three crane species preferred natural wetlands to agricultural fields when the abundance of natural foods was high. The abundance of Vallisneria tubers, and probably P. criopolitanum, greatly influenced the dietary compositions, breadths and overlap of cranes. During periods of preferred resource shortage, White-naped Cranes and Hooded Cranes widened their dietary niches, while Siberian Cranes maintained a stable niche width. The dietary niche overlap among crane species increased substantially under conditions of plentiful preferred food resources.ConclusionsOur study emphasizes the superior quality of natural wetlands compared to agricultural fields as foraging habitats for cranes. To provide safer and better foraging areas for cranes, it is urgent to restore the submerged plants at Poyang Lake. While high dietary niche overlap is often interpreted as intense interspecific competition, our study highlights the importance of taking food abundance into account.

Migrating Whooping Cranes avoid wind-energy infrastructure when selecting stopover habitat.

Electricity generation from renewable-energy sources has increased dramatically worldwide in recent decades. Risks associated with wind-energy infrastructure are not well understood for endangered Whooping Cranes (Grus americana) or other vulnerable Crane populations. From 2010 to 2016, we monitored 57 Whooping Cranes with remote-telemetry devices in the United States Great Plains to determine potential changes in migration distribution (i.e., avoidance) caused by presence of wind-energy infrastructure. During our study, the number of wind towers tripled in the Whooping Crane migration corridor and quadrupled in the corridor's center. Median distance of Whooping Crane locations from nearest wind tower was 52.1km, and 99% of locations were >4.3km from wind towers. A habitat selection analysis revealed that Whooping Cranes used areas ≤5.0km (95% confidence interval [CI]4.8-5.4) from towers less than expected (i.e., zone of influence) and that Whooping Cranes were 20 times (95% CI 14-64) more likely to use areas outside compared to adjacent to towers. Eighty percent of Whooping Crane locations and 20% of wind towers were located in areas with the highest relative probability of Whooping Crane use based on our model, which comprised 20% of the study area. Whooping Cranes selected for these places, whereas developers constructed wind infrastructure at random relative to desirable Whooping Crane habitat. As of early 2020, 4.6% of the study area and 5.0% of the highest-selected Whooping Crane habitat were within the collective zone of influence. The affected area equates to habitat loss ascribed to wind-energy infrastructure; losses from other disturbances have not been quantified. Continued growth of the Whooping Crane population during this period of wind infrastructure construction suggests no immediate population-level consequences. Chronic or lag effects of habitat loss are unknown but possible for long-lived species. Preferentially constructing future wind infrastructure outside of the migration corridor or inside of the corridor at sites with low probability of Whooping Crane use would allow for continued wind-energy development in the Great Plains with minimal additional risk to highly selected habitat that supports recovery of this endangered species.

Assessing habitat suitability and habitat fragmentation for endangered Siberian cranes in Poyang Lake region, China

Poyang Lake is located in the middle and lower reaches of the Yangtze River in China. It is the most important wintering area for the endangered Siberian cranes. Identifying the scale characteristics of habitat selection for Siberian cranes is essential for habitat conservation. In this study, a habitat suitability index (HSI) model based on multiscale habitat features was developed to assess the distribution and fragmentation degree of the suitable habitat for Siberian cranes before and after the construction of the proposed Poyang Lake Hydraulic Project (PLHP). The habitat of the entire lake area was divided into four ranks on the basis of HSI values. 2D shallow-water equations (SWEs), combined with remote sensing and geographic information system technology, were utilized to determine the key habitat features. Results indicated that the established HSI model could effectively recognize the potentially suitable habitats for Siberian cranes in Poyang Lake. The highly suitable habitat in the wet year was larger than that in the dry year, and the complexity of patch shapes and patch fragmentation increased. The influence of the PLHP on the suitable habitat for cranes mainly depended on its regulated water level, and this project could promote the formation and reduce the fragmentation degree of the suitable habitat under a properly regulated water level in the dry year. However, a higher regulated water level may cause a considerable negative impact on the distribution of suitable habitats in both years. This study provided a quantitative method to evaluate the potentially suitable habitats for Siberian cranes, and it could serve as a reference for the water level management of the proposed PLHP.

Spatiotemporal Variation of Siberian Crane Habitats and the Response to Water Level in Poyang Lake Wetland, China

The Poyang Lake wetland in China is the largest wintering destination for Siberian cranes worldwide. Understanding the spatiotemporal characteristics of crane habitats is of great importance for ecological environment governance and biodiversity protection. The shallow water, grassland, and soft mudflat regions of the Poyang Lake wetland are ideal habitats for wintering Siberian cranes. Based on Landsat Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+), and Operational Land Imager (OLI) remote sensing images, habitat areas were extracted and associated with various water levels taken on multiple dates. Landscape metrics were applied to describe the spatial structural characteristics of the crane habitats, and spatial statistics are used to explore the cold and hot spots of their distribution. Moreover, three indicators including sustainability, stability, and variety were applied to evaluate the vulnerability of the crane habitats under different hydrological conditions. Our findings indicate: (a) The main crane habitats exhibit a gradual decreasing degree of fragmentation in time, an obvious uncertainty of shape complexity and a relatively stable connectivity. (b) The crane habitats have a consistent spatial pattern of highly aggregated distributions associated with various water levels. (c) The hot spots of the habitats formed multiple “sheet” belts centered on the “Lake Enclosed in Autumn” regions, while the cold spots indicate a spatial pattern of axial distributions. (d) The majority of the hot spots of the habitats were distributed in sub-lakes found in the southeast part of the Poyang Lake watershed and the Nanjishan and Wucheng nature reserves, while the cold spots were mainly distributed in the main channels of the basins of Poyang Lake. (e) The sustainable habitats were mainly distributed in the “Lake Enclosed in Autumn” regions and intensively aggregated in two national nature reserves. (f) Under conditions of extremely low to average water levels (5.3–11.46 m), an increase of water level causes a decrease of the stability and variety of the crane habitats and weakens the aggregation structure.

The Path Forward: Conservation of Climate Change-Affected Breeding Habitat of Red-crowned Cranes near Zhalong Reserve, China

The Path Forward: Conservation of Climate Change-Affected Breeding Habitat of Red-crowned Cranes near Zhalong Reserve, China

Pattern change of the coastal wetland system and its dynamic impact on the habitat of red-crowned cranes in Yancheng， Jiangsu Province

Pattern change of the coastal wetland system and its dynamic impact on the habitat of red-crowned cranes in Yancheng， Jiangsu Province

Spatial Analysis of Potential Nesting Habitat for Florida Sandhill Cranes

AbstractThe Florida sandhill crane Antigone canadensis pratensis is designated as threatened by the state of Florida, where there is an urgent need to map and quantify available habitat. First, we used habitat suitability index (HSI) modelling to map and assess potential nesting habitat for sandhill cranes in Florida. Second, we used spatial optimization approaches to calculate the maximum number of breeding pairs that can simultaneously occupy potential nests given that they both must be of some minimum quality and must be spaced some minimal distance apart. Mapping results reveal that nesting habitat is concentrated in the central portion of the state, with adequate brooding habitat appearing to be the most limiting factor affecting habitat suitability. Assuming nesting only occurs in habitat rated as high quality (HSI ≥ 0.7) and spacing between adjacent nests is ≥1,000 m, we conservatively estimate that 5,540 nesting pairs of Florida sandhill cranes can potentially be supported. Additional nesting pairs may be supported in habitats of marginal (HSI ≥ 0.3; 14,530) to moderate (HSI ≥ 0.5; 8,723) quality. The suitability maps and breeding pair estimates can be used to identify important habitat areas to focus crane conservation efforts, determine potentially limiting habitat features across the landscape, and potentially guide future population monitoring efforts. For example, grassland or prairie restoration could be used to potentially increase nesting pairs in the southern portion of the state where emergent wetlands are abundant but brooding habitat is lacking.

Predicted effects of Chinese national park policy on wildlife habitat provisioning: Experience from a plateau wetland ecosystem

Abstract Understanding the ecological consequences of conservation policies on wildlife is critical for species conservation and policy implementation. China began to call for establishing a national park system in 2013 and used national parks as the predominant feature for its system of protected areas in 2019. Payment for ecosystem services (PES) and relocation constitute two important management strategies in new Chinese national parks and protected area system. To better understand the potential outcomes of such programs, we studied the winter foraging distribution of the threatened Black-necked Crane (Grus nigricollis), a flagship species of plateau wetlands, in Dashanbao Protected Area, SW China. Field survey data were combined with environmental variables and land use maps to model winter foraging habitat with respect to human settlements subject to PES and relocation. High suitability for foraging was mapped in the core zone around crane roosting sites, villages, and far from disturbance (e.g. main roads). Aiming at converting farmland to wetland, the payment for ecosystem services programs increased probability of occurrence of cranes by changing land cover in appropriate areas relative to crane roosts and other spatially distributed variables. Surprisingly, areas within 1 km of villages were recognized as highly suitable foraging habitats for cranes, which depend on waste grain in farmland in winter, revealing the potential risk of relocation-induced food shortage for wintering cranes. We argue that as an effective strategy in improving wildlife habitat, PES should be encouraged and relocation programs that change the existing long-term established human-wildlife interactions should be implemented only under full understanding of these relationships. As a pioneer study of the effects of conservation policy on wetland ecosystems in China, this study could shed light on conservation management for such ecosystem and species showing high dependence on a human modified environment. Future work should also focus on the social effects of these conservation strategies, especially relocation, during national park planning in China.

Identification of the Breeding Range of the Hooded Crane

Abstract The Hooded Crane Grus monacha remains the least known crane species in terms of its breeding range. Since 1985, typical wetlands meeting the characteristics of the typical Hooded Crane habitat have been surveyed between 56° and 66°N and between 108° and 136°E. Within the Lena River Basin, well-defined extensive breeding grounds of the Hooded Crane have been observed in the middle Aldan River Basin. Surveys of representative swampy headwaters, river reaches, and large watershed depressions, have revealed no other similar breeding grounds within the rest of the Lena River Basin, including areas attributed to the only known breeding grounds outside Manchuria. Within the extent of occurrence in the Lena River Basin and adjoining areas of the Olenyek, Khatanga and Yenisei river basins, breeding Hooded Cranes are presumably highly scattered. Solitary pairs are likely to breed hundreds of kilometers apart. Based on the distribution of wetlands, breeding grounds comparable to the middle Aldan River may occur in the basins of the upper Vilyui and the adjoining Moero and Kotui rivers. Evidence suggests that reports from local people are mostly plausible and consistent with maps and satellite images showing wetland habitat similar to that used by the Hooded Crane. Therefore, in the absence of direct data, the reports of the occurrence/nesting of Hooded Cranes beyond the Arctic Circle, particularly in the Olenyek River Basin quoted by Andreev ( 1974 ), should be given credence when delineating the breeding range. The region, including the Lena River Basin is too vast and difficult of access for aerial surveys to be practical. Tracking, based on navigation satellite systems, rather than stepwise ground surveys, is the only practical method for obtaining significant information over a short period of time.

Ecological Security Assessment of the Yancheng National Nature Reserve Based on GIS

This study used remote sensing and GIS to analyze the landscape pattern changes in the Yancheng Nature Reserve from 1983 to 2018, established an evaluation index system based on the regional natural-socio-economic complex ecosystem security pattern, and then analyzed the spatial characteristics of ecological security changes and discusses reasons for these changes. The results show that the landscape pattern changed dramatically from natural landscape to a mixture of natural landscape and artificial landscape from 1983 to 2018 due to the intensification of human activities. At present, the ecological security status of the protected areas is not optimistic. From the perspective of the survival status of red-crowned cranes, the protected areas are suitable. However, due to the increase of human activities and policy adjustments, the habitat of red-crowned cranes is fragmented. The red-crowned crane currently gathers in localized areas such as the core area and the buffer zone. We should pay more attention to management, policy development and the environmental awareness of local residents. At the same time, it is necessary to reduce the intensity of human activities within the reserve.

Grey Crowned Crane and Shoebills Conservation Status and Linkage to Livelihoods of Lake Victoria Shores Adjacent Communities in Mayuge District, Eastern Uganda

This research was done among communities living adjacent to Lake Victoria Shores in Mayuge District to generate knowledge on Shoebill, Grey Crowned Crane conservation status and linkage to livelihoods. This knowledge was necessary to guide design and implementation of interventions that would deliver on the species conservation and adjacent communities’ livelihood benefits at the same time. We obtained information through individual interviews with 101 members of households from targeted communities and key informers-technical officials from the district, and analysed this data using Statistical Package for the Social Sciences (SPSS) by Bryman and Cramer, (2011) Version 20. The results were then subjected to validation using focus group discussions with 10 groups of between 8 - 15 individuals representing the targeted communities and other stakeholders and the results from this further validated with ≥250 representatives of these stakeholders in a one day workshop and with evidences collected during field observations, before synthesis. The findings show: Grey Crowned Crane habitats declining due to mining, agriculture, fishing activities by adjacent communities for their livelihoods (food and income from sale of produce obtained from the species’ habitats). The communities say they need to be engaged in development and implementation of integrated interventions that will improve their livelihoods while securing conservation for Grey Crowned Cranes. They among others propose ecotourism enterprises, training and sensitization on environment and wildlife conservation practices, policies and laws to enhance their knowledge and compliance in management. The fisher folk say fish is often found within Grey Crowned Cranes’ habitats and breeding grounds in the Lake and to avoid destroying the habitats, they need engine boats and standard fishing nets to enable fishing far away in the deeper waters. Crop farming communities say they need commercial, soil fertility improving tree species to plant boundary to the buffer zones so that they can prevent cultivation encroachment on Grey Crowned Crane habitats in the Lake Shores. The findings also reveal need for Grey Crowned Crane population structure studies, and, that of shoebill presence to determine management strategies for their survival in habitats.

Research on the influence of land use change to habitat of cranes in Shengjin Lake wetland.

Shengjin Lake wetland reserve is an important habitat for the winter cranes of our country, and the change of land use structure in the area have had a vital influence on the winter cranes and their habitat. The TM remote sensing images of 1986-2015years were selected in this paper, and the land use change model and gray relational analysis model were used to analyze the effect of land use degree on the habitat of the winter crane and correlation degree between cranes and land use of Shengjin lake wetland. The land use transformation method was employed to analyze the transfer of the habitat of cranes and the relationship between the size of the cranes habitat and the number of populations. The results showed that the degree of land use change fluctuated greatly in different periods, and comprehensive index of land use degree between 220 and 260, also the land use was based on woodland, grassland, and water and their effect on the habitat was limited; the marsh land had the highest retention rate among the cranes habitat being 34.44%. While the reed flat had the lowest rate, only 15.36%, and the reed breach land was mainly transferred to marsh and dry land, 23.22% and 18.16%, respectively. The mud was mainly transferred to water and farmland, respectively, for 31.79% and 27.75%; except the period from 2011 to 2015, the change of habitat area was basically consistent with the change of the number of cranes.

Speciation and Ecological Risks of Cobalt and Antimony in Black-Necked Crane (<i>Grus nigricollis</i>) Habitat Sediments in China’s Caohai Lake

Speciation and Ecological Risks of Cobalt and Antimony in Black-Necked Crane (<i>Grus nigricollis</i>) Habitat Sediments in China’s Caohai Lake

Habitat quality of overwintering red-crowned cranes based on ecological niche modeling

Ecological niche modeling is particularly valuable for predicting the true and potential distribution of wild birds. The core zone of the Yancheng National Nature Reserve (YNNR) is the largest overwintering habitat of red-crowned cranes in the world. Based on a GF-2 image in 2015 and field data related to micro-habitats of cranes, five functional factors were selected and analyzed with maximum entropy (MaxEnt) and boosted regression tree (BRT) models. The prediction results of the MaxEnt and BRT algorithms reached outstanding levels. Landscape type was the most important environmental factor affecting the habitat quality of overwintering cranes, while distance to water sources was the least contributing factors in both models. The response curve of the BRT was more reasonable than the MaxEnt at explaining habitat selection and utilization by cranes. It revealed that superior habitats are principally distributed in Suaeda salsa in natural wetlands. This habitat currently faces serious fragmentation and islandization. This study evaluates the quality of overwintering habitat for red-crowned cranes based on ecological niche modeling. The results provide a scientific basis for the protection of the overwintering habitat of this species of crane, and it is critical for species protection and management planning of nature reserves.

Effects of land-use change on the distribution of the wintering red-crowned crane (Grus japonensis) in the coastal area of northern Jiangsu Province, China

The coastal area of northern Jiangsu (CNJ) is the largest silt coastal zone along the western Pacific Coast. This area is a newly established world natural heritage site and is also the largest winter habitat for the red-crowned crane in the world. However, rapid economic development in the study area has led to great changes in the types and intensities of land-use, which has had an effect on the distribution of wintering red-crowned cranes. In this paper, we first analyzed land-use change and determined the spatiotemporal evolution of land-use types and intensities in the study area. Then, the distribution of the red-crowned cranes was analyzed over various years. Finally, a geographically weighted regression (GWR) model was adopted to study the spatial differences in the effects of land-use types and intensity changes on the distribution of the cranes. The results showed that salt marsh (p<0.01), salt field (p<0.05) and paddy field (p<0.05) were positively correlated with red-crowned cranes. Dry land (p<0.05), construction land (p<0.01) and aquaculture pond (p<0.05) were negatively correlated with red-crowned cranes. There was a strongly negative correlation between land-use intensity and the red-crowned cranes (p<0.01). These positive and negative factors had significant spatial heterogeneity. Given these differences and the current local economic and land policies, we proposed the concrete countermeasures for red-crowned crane habitat protection and established a “friendly” land-use pattern that is beneficial for the protection of the crane population and restoration of its habitat.

Red-crowned crane (Grus japonensis) prefers postharvest reed beds during winter period in Yancheng National Nature Reserve.

Reed beds represent an important habitat for the survival of birds by providing favorable foraging and reproduction conditions. Reed management, as a traditional agricultural activity, primarily includes water level control and vegetation removal by cutting. Red-crowned crane (Grus japonensis) is one of the most endangered cranes, and their population continues to decline due to habitat loss caused by artificial activities. A lack of research relating to how reed management affects crane habitat distribution patterns throughout the wintering period hinders our ability to offer conservation recommendations. In the present study, we explored the effect of reed management on the habitat distribution patterns and analyzed the food resources of red-crowned crane in the Yancheng National Nature Reserve (YNNR). According to the reed management activities in December, we divided the wintering period into two phases: the preharvest period and the postharvest period. Throughout the wintering period, the number of cranes recorded in the common seepweed (Suaeda glauca) tidal flats remained stable, but cranes were rarely recorded in the smooth cordgrass (Spartina alterniflora) tidal flats and aquaculture fish ponds. The number of cranes, however, showed a noticeable fluctuation in the reed beds during the two periods. Before the reed harvest, only a small proportion of cranes were recorded in the reed beds (relative abundance = 2.9%). However, more cranes (relative abundance = 61.0%) were recorded after the reed harvest. Water was introduced from adjacent rivers and fish ponds to submerge the cut reed beds. Changes in potential animal food resources (items and biomass) might be one of the vital reasons for the preference of cranes to the postharvest reed beds. Our results suggest that traditional reed management in the YNNR could benefit this flagship crane species that winters in the wetland system. However, as reed harvest has been forbidden in the core zone for conservation purposes since 2016, further research is needed to verify whether forbidding the harvest of reeds is reasonable.

Potential habitat and priority protection area of cranes with climate change in the Great Xing'an Mountains, China

To clarify the impacts of climate change on the potential distribution of six crane species in the Great Xing'an Mountains region, and promote the effective protection of these species, we selected key environmental variables such as climate, topography, and vegetation type based on Pearson correlation and Jackknife analysis, and modeled the potential distribution of six crane species in the Great Xing'an Mountains using MaxEnt with the current and the future climate change scenarios (RCP4.5 and RCP8.5). We identified the priority protection areas (PPAs) and the target PPAs by zonation and ArcGIS. The results showed that with the current climate condition, the sui-table habitats of these species were mainly distributed in the central and the northwest part of the Great Xing'an Mountains. With RCP4.5 and RCP8.5 scenarios, the suitable habitats of Grus monacha, Grus japonensis, Grus vipio, Grus grus and Anthropoides virgo would decrease, while that of Grus leucogeranus would expand by 5.4%-6.3%. With current and the future climate change scenarios, the PPAs of these species were mainly distributed in the northwest, southeast and west-central parts of the Great Xing'an Mountains. The protect rate could reach about 20.1%-23.8% of the target PPAs conserved by protected areas (PAs). The protection gaps were mainly distributed in the west of Mohe County, the north-central of Ergun, the central and east of Genhe, the northeast of Yakeshi, and the south of Oroqen Autonomous Banner. We proposed to expand PAs to provide a strong guarantee for the effective protection of cranes species.

Effects of Spartina alterniflora invasion on quality of the red-crowned crane (Grus japonensis) wintering habitat.

The core zone of the Yancheng National Natural Reserve (YNNR) in China is the largest wintering habitat of red-crowned cranes (cranes) in the world. However, the invasion of Spartina alterniflora (S. alterniflora) not only changed the original landscape structure of the wetlands but also impacted the cranes' habitats in the YNNR. In this paper, field investigation data and landscape pattern indices were used to analyze the effects of the S. alterniflora invasion on the habitat quality of wintering cranes. The results indicate that the seep weed (Suaeda salsa) in the natural wetland and the common reed (Phragmites australis) in the managed wetland both provide suitable habitats for cranes. However, the cranes prefer the natural wetland more. The explosive growth of S. alterniflora in the natural area has led to a significant reduction of the cranes' habitat. The area of crane habitat decreased from 52.07km2 in 2000 to 22.36km2 in 2015. As a result of the S. alterniflora invasion, the benthic biomass has declined, which has negatively impacted the quantity and structure of the food utilized by the cranes. This study has both theoretical and practical significance and provides a scientific basis for protecting the wintering habitat of the red-crowned cranes.