Literature type: Scientific
Journal: Ecological Engineering
Volume: 88 , Pages: 90–98.
Full reference: Guan, L., Lei, J., Zuo, A., Zhang, H., Lei, G. & Wen, L. 2016. Optimizing the timing of water level recession for conservation of wintering geese in Dongting Lake, China. Ecological Engineering 88: 90–98. https://www.dx.doi.org/10.1016/j.ecoleng.2015.12.009
Habitat suitability and selection are key concepts in wildlife management, especially in protection of critical habitat and conservation of sensitive and endangered populations. In recent years, many approaches have been developed to link habitat suitability with animal occurrence and abundance. These approaches typically involve identifying existing habitats, defining habitat quality metrics, and estimating the association between animal occurrence/abundance and measured habitat metrics. In this study, we first tested whether we could measure habitat quality at Dongting Lake, China, one of the most important migratory waterbird wintering sites in the East Asian Flyway, for a group of Anatidae using metrics derived from the freely available multi-temporal MODIS vegetation index. The results showed that goose counts could be sufficiently modelled using mean winter season EVI (enhanced vegetation index) and habitat size computed from EVI time series and topographic wetness index (TWI). We then quantified the relationships between hydrological regimes and the habitat quality metrics. Our findings suggested that the timing of optimal water draw down should be early to mid October to ensure quality food sources for the wintering geese in Dongting Lake. The results have direct conservation implications as water recession timing is highly manageable through water flow regulation.
Literature type: Scientific
Journal: Environmental management
Volume: 54 , Pages: 1331–1341
Full reference: Guan, L., Wen, L., Feng, D., Zhang, H., & Lei, G. 2014. Delayed flood recession in central Yangtze floodplains can cause significant food shortages for wintering geese: results of inundation experiment. Environmental management 54: 1331–1341 https://www.dx.doi.org/10.1007/s00267-014-0350-7
Carex meadows are critical habitat for wintering geese in the floodplains of the middle and lower reaches of Yangtze River, China. These meadows follow a growth cycle closely tied to the seasonal hydrological fluctuation: as water levels recede in the fall, exposed mudflats provide habitat for Carex spp. growth. The seasonal growth of Carex overlaps the arrival of wintering geese and provides an important food source for the migrants. Recent alterations to the Yangtze's hydrology, however, have disrupted the synchronous relationship between water levels, Carex growth and wintering geese at Dongting Lake. In October 2012, we carried out an outdoor mesocosm experiment to investigate potential impacts of delayed water recession on the germination and growth of Carex heterolepis, the dominant Carex species at Dongting Lake, to understand how changes in hydrology might impact wintering goose habitat. Results showed that the delayed flood recession exerted significant impact on the first growth cycle of Carex growth. Prolonged inundation significantly lowered the intrinsic growth rate (P = 0.03) and maximum growth rates (P = 0.02). It also took significantly longer time to reach the peak growth rate (P = 0.04 and 0.05 for number of shoot and biomass, respectively). As a result, biomass accumulation was reduced by 45, 62 and 90 % for 10-day, 20-day and 30-day inundation treatments, respectively. These results indicate a severe risk of food shortage for wintering geese when water recession delayed. This potential risk should be taken into consideration when operating any hydrological control structures that alter the flood regimes in Dongting Lake.
Number of results: 2