Waterbird Communities in Subsidence Wetlands Created by Underground Coal Mining in China : Effects of Multi-Scale Environmental and Anthropogenic Variables
Li, Chunlin ; Yang, Sen ; Zha, Daode ; Zhang, Yong ; Boer, Willem F. de - \ 2019
Environmental Conservation 46 (2019)1. - ISSN 0376-8929 - p. 67 - 75.
Habitat loss - subsidence wetland - waterbird - wetland degradation
SummaryUnderground coal mining in the North China Plain has created large-scale subsidence wetlands that may attract waterbirds that use them as complementary habitats. However, no study has been conducted to understand avian use of these created wetlands, inhibiting the formulation of effective management plans. Here, we carried out 12 semi-monthly surveys in 55 subsidence wetlands during the 2016-2017 migration and wintering period and performed direct multivariate analyses, combined with variance partitioning, to test the effects of multi-scale habitat variables on the waterbird assemblages. A total of 89 349 waterbirds representing 60 species were recorded, with seasonal fluctuations in species richness and bird abundance. Waterbird community structures were shaped by four groups of variables at local, landscape and human levels with different effects among seasons. Anthropogenic disturbance was the most important factor group, negatively affecting most guilds. Waterbirds in this human-dominated environment are under a variety of potential threats that should be further studied. The subsidence wetlands are still expanding, and if managed effectively, may provide important complementary habitats for a wide array of waterbird species, particularly for those migrating along the East Asian-Australasian Flyway. Our study provides key baseline data regarding the waterbird communities and may help with the designing of effective management and conservation plans.
Autonomous Generation and Loading of DNA Guides by Bacterial Argonaute
Swarts, Daan C. ; Szczepaniak, Malwina ; Sheng, Gang ; Chandradoss, Stanley D. ; Zhu, Yifan ; Timmers, Elizabeth M. ; Zhang, Yong ; Zhao, Hongtu ; Lou, Jizhong ; Wang, Yanli ; Joo, Chirlmin ; Oost, John van der - \ 2017
Molecular Cell 65 (2017)6. - ISSN 1097-2765 - p. 985 - 998.
Ago - DNA chopping - Guide generation - Guide loading - PAgo - Prokaryotic argonaute - RNA interference - SiDNA - Small interfering DNA - TtAgo
Several prokaryotic Argonaute proteins (pAgos) utilize small DNA guides to mediate host defense by targeting invading DNA complementary to the DNA guide. It is unknown how these DNA guides are being generated and loaded onto pAgo. Here, we demonstrate that guide-free Argonaute from Thermus thermophilus (TtAgo) can degrade double-stranded DNA (dsDNA), thereby generating small dsDNA fragments that subsequently are loaded onto TtAgo. Combining single-molecule fluorescence, molecular dynamic simulations, and structural studies, we show that TtAgo loads dsDNA molecules with a preference toward a deoxyguanosine on the passenger strand at the position opposite to the 5' end of the guide strand. This explains why in vivo TtAgo is preferentially loaded with guides with a 5' end deoxycytidine. Our data demonstrate that TtAgo can independently generate and selectively load functional DNA guides. Swarts et al. demonstrate that, in absence of a guide, the Argonaute protein from Thermus thermophilus chops (degrades) double-stranded DNA. Chopped DNA is sequence-specifically bound by TtAgo, which results in loading of DNA guides with a 5' end deoxycytidine. The TtAgo-guide complex can subsequently bind and cleave cognate DNA targets.
In-situ carboxylate recovery and simultaneous pH control with tailor-configured bipolar membrane electrodialysis during continuous mixed culture fermentation
Arslan, D. ; Zhang, Y. ; Steinbusch, K.J.J. ; Diels, L. ; Hamelers, Hubertus V.M. ; Buisman, C.J.N. ; Wever, H. de - \ 2017
Separation and Purification Technology 175 (2017). - ISSN 1383-5866 - p. 27 - 35.
Bipolar membrane - Electrodialysis - Fermentation - ISPR - Short chain carboxylates
Anaerobic fermentation of organic waste streams by mixed culture generates a mixture of short chain carboxylic acids. To avoid inhibitory effects of the acids or their consumption in internal conversion reactions in the mixed culture environment, in-situ recovery of acids can be beneficial. In this study, electrodialysis with bipolar membranes (EDBM) was applied to a mixed culture fermentation on organic waste streams using a novel EDBM stack with “direct contact” operation mode. We could demonstrate simultaneous recovery of carboxylates from the fermenter by the EDBM stack while in-situ generation and transport of hydroxyl ions to the fermenter allowed direct pH control. Experiments showed productivity increase after EDBM coupling to the fermenter, and complete elimination of external base consumption. It was also observed that EDBM was able to drive the mixed culture fermentation towards acetate and propionate type of carboxylates.
Experimental evidence shows the importance of behavioural plasticity and body size under competition in waterfowl
Zhang, Yong ; Prins, Herbert H.T. ; Versluijs, Martijn ; Wessels, Rick ; Cao, Lei ; Boer, Fred de - \ 2016
PLoS ONE 11 (2016)10. - ISSN 1932-6203
When differently sized species feed on the same resources, interference competition may occur, which may negatively affect their food intake rate. It is expected that competition between species also alters behaviour and feeding patch selection. To assess these changes in behaviour and patch selection, we the functional response for each species and then recorded their behaviour and patch selection with and without potential competitors, using different species combinations. Our results showed that all three species acquired the highest nitrogen intake at relatively tall swards (6, 9 cm) when foraging in single species flocks in the functional response experiment. Goose species were offered foraging patches differing in sward height with and without competitors, and we applied an experimental approach using captive birds of three differently sized Anatidae species: wigeon (Anas penelope) (∼600 g), swan goose (Anser cygnoides) (∼2700 g) and bean goose (Anser fabalis) (∼3200 g). We quantified tested for the effect of competition on foraging behaviour. The mean percentage of time spent feeding and being vigilant did not change under competition for all species. However, all species utilized strategies that increased their peck rate on patches across different sward heights, resulting in the same instantaneous and nitrogen intake rate. Our results suggest that variation in peck rate over different swards height permits Anatidae herbivores to compensate for the loss of intake under competition, illustrating the importance of behavioural plasticity in heterogeneous environments when competing with other species for resources.
Taxonomy of the order Mononegavirales : update 2016
Afonso, Claudio L. ; Amarasinghe, Gaya K. ; Bányai, Krisztián ; Bào, Yīmíng ; Basler, Christopher F. ; Bavari, Sina ; Bejerman, Nicolás ; Blasdell, Kim R. ; Briand, François Xavier ; Briese, Thomas ; Bukreyev, Alexander ; Calisher, Charles H. ; Chandran, Kartik ; Chéng, Jiāsēn ; Clawson, Anna N. ; Collins, Peter L. ; Dietzgen, Ralf G. ; Dolnik, Olga ; Domier, Leslie L. ; Dürrwald, Ralf ; Dye, John M. ; Easton, Andrew J. ; Ebihara, Hideki ; Farkas, Szilvia L. ; Freitas-Astúa, Juliana ; Formenty, Pierre ; Fouchier, Ron A.M. ; Fù, Yànpíng ; Ghedin, Elodie ; Goodin, Michael M. ; Hewson, Roger ; Horie, Masayuki ; Hyndman, Timothy H. ; Jiāng, Dàohóng ; Kitajima, Elliot W. ; Kobinger, Gary P. ; Kondo, Hideki ; Kurath, Gael ; Lamb, Robert A. ; Lenardon, Sergio ; Leroy, Eric M. ; Li, Ci Xiu ; Lin, Xian Dan ; Liú, Lìjiāng ; Longdon, Ben ; Marton, Szilvia ; Maisner, Andrea ; Mühlberger, Elke ; Netesov, Sergey V. ; Nowotny, Norbert ; Patterson, Jean L. ; Payne, Susan L. ; Paweska, Janusz T. ; Randall, Rick E. ; Rima, Bertus K. ; Rota, Paul ; Rubbenstroth, Dennis ; Schwemmle, Martin ; Shi, Mang ; Smither, Sophie J. ; Stenglein, Mark D. ; Stone, David M. ; Takada, Ayato ; Terregino, Calogero ; Tesh, Robert B. ; Tian, Jun Hua ; Tomonaga, Keizo ; Tordo, Noël ; Towner, Jonathan S. ; Vasilakis, Nikos ; Verbeek, Martin ; Volchkov, Viktor E. ; Wahl-Jensen, Victoria ; Walsh, John A. ; Walker, Peter J. ; Wang, David ; Wang, Lin Fa ; Wetzel, Thierry ; Whitfield, Anna E. ; Xiè, Jiǎtāo ; Yuen, Kwok Yung ; Zhang, Yong Zhen ; Kuhn, Jens H. - \ 2016
Archives of Virology 161 (2016)8. - ISSN 0304-8608 - p. 2351 - 2360.
In 2016, the order Mononegavirales was emended through the addition of two new families (Mymonaviridae and Sunviridae), the elevation of the paramyxoviral subfamily Pneumovirinae to family status (Pneumoviridae), the addition of five free-floating genera (Anphevirus, Arlivirus, Chengtivirus, Crustavirus, and Wastrivirus), and several other changes at the genus and species levels. This article presents the updated taxonomy of the order Mononegavirales as now accepted by the International Committee on Taxonomy of Viruses (ICTV).
Variation in elevation and sward height facilitate coexistence of goose species through allometric responses in wetlands
Zhang, Yong ; Prins, Herbert H.T. ; Cao, Lei ; Zhao, Meijuan ; Boer, Fred de - \ 2016
Waterbirds 39 (2016)1. - ISSN 1524-4695 - p. 34 - 44.
Anser albifrons - Anser fabalis - Bean Goose - body size - forage quality - forage quantity - grassland - Greater White-fronted Goose - habitat selection - heterogeneity
Allometric scaling law predicts that herbivores respond differently to the availability of resources, mediated by body size. However, studies of allometric responses have often focused on animals with a relatively large difference in body size. Here, using a correlative field study, habitat use by two herbivorous species, the Bean Goose (Anser fabalis) and the Greater White-fronted Goose (A. albifrons), with a relatively small difference in body size was investigated during the wintering period. Both a generalized linear mixed model and a mixed logistic regression model showed that both species selected lower lying areas that were recently exposed, and, as expected, the smaller Greater White-fronted Goose showed a stronger selection of foraging habitat than the larger Bean Goose. Sward height also influenced habitat selection by both species, and the smaller species selected shorter swards than the larger species. In terms of forage quality, both models failed to detect a significant effect of nitrogen content on goose habitat selection. A logistic regression model showed that structural heterogeneity of the sward negatively correlated with the patch selection of the smaller species, but for the larger species such a correlation was not found. In agreement with our hypotheses, our results provide some preliminary indication that coexistence of the two goose species studied here might be mediated by an allometric response even if the difference in body size is relatively small.
Wild geese of the Yangtze River : their ecology and conservation
Zhang, Y. - \ 2016
Wageningen University. Promotor(en): Herbert Prins; Fred de Boer; L. Cao. - Wageningen : Wageningen University - ISBN 9789462576049 - 147
geese - anatidae - anser - animal ecology - wildlife management - nature conservation - hydrology - habitat selection - rivers - china - ganzen - anatidae - anser - dierecologie - wildbeheer - natuurbescherming - hydrologie - habitatselectie - rivieren - china
Habitat selection is a process in which organisms decide to choose a suitable site for nesting, roosting or foraging. The question where the organisms are, and when they will leave are two of the fundamental questions frequently asked by ecologists. Habitat selection is affected by various abiotic and biotic determinants, varying over different spatial and temporal scales. In addition, an animal’s body size, determining its daily demands and its digestion capacity, plays an important role in foraging and habitat selection. This is because forage quality often decreases with increasing forage quantity. Therefore, herbivores often face a trade-off between forage quality and quantity. Although studies on habitat selection have offered substantial insights into the effect of various ecological factors, myriad effects of habitat and its’ surrounding are still not clearly understood, as former studies concerning this topic normally focus on a single species or a single spatial scale.
Migrating goose species are herbivorous with more or less similar habitat requirements and hence often mix in the field. Studying habitat selection of different goose species is attractive as they are from the same guild but differ in body size. In this thesis, I study the effects of various variables on habitat selection of different Anatidae species over different spatial scales, answering the question how ecological and anthropogenic variables affect Anatidae species habitat selection and population sizes and if these effects vary over different spatial scales.
First, I studied the habitat selection of Anatidae species under the condition with and without interference competition using an experimental approach in Chapter 2. To do this, I offered geese and ducks foraging patches with various swards heights. My results showed that all three species acquired the highest nitrogen intake at relatively tall swards (on 6 or 9 cm, but not on 3 cm) when foraging in single species flocks in the functional response experiment. When they were offered foraging patches differing in sward height with and without competitors, their mean percentage of feeding time did not change, whereas all species increased their percentage of time being vigilant except for the dominant swan goose. All species utilized strategies that increased their peck rate on patches across different sward heights when foraging together with other species, resulting in the same instantaneous and nitrogen intake rate than when foraging in a single species flocks. My results suggest that variation in peck rate over different swards height permits Anatidae herbivores to increase nitrogen intake under competition to compensate for the loss of intake, illustrating the importance of behavioural plasticity in heterogeneous environments when competing with other species for resources.
In Chapter 3, using a correlative field study, I analysed the habitat selection of two differently sized grazing goose species at site level. I found that both species selected lower lying area where the swards became recently exposed, due to receding water levels. However, the smaller species was more sensitive to this elevation gradient. Moreover, sward height negatively affected both species habitat selection with a stronger effect on the smaller species. This result highlighted the importance of body size on facilitating species coexistence and habitat segregation. Not in agreement with the results from most experimental studies, I found that nitrogen content did not influence habitat selection of both species. This conflicting result suggests that additional factors should be carefully considered when applying outcomes from experimental studies to field situations.
In Chapter 4, I studied habitat selection of the two goose species at a lake level by analysing the effect of ecological and anthropogenic variables. My results supported the individual-area relationship as only patch area had a significant effect on both species habitat selection, and other variables that were related to food availability and disturbance, were not significant. In addition, a facilitation effect of grazing livestock on geese habitat selection was detected, indicating that larger grazing herbivores can facilitate geese foraging by removing the taller and lower quality food from the top. As patch area size in wetlands is directly linked to water levels fluctuations, this result demonstrated that modifying hydrological regimes can enlarge the capacity of wetlands for migratory birds.
In Chapter 5, I further expanded my study area to the flood plain level of the Yangtze, testing for the effect of various abiotic and biotic variables on several Anatidae species habitat selection and population trends. I showed that slope and climate factors were the most important ones affecting habitat selection and distribution of Anatidae species. Furthermore, I demonstrated that the current protection policies may not stop the declining population trends but might buffer to some extent against a rapid decline in numbers in wetlands with a higher level protection status. This result points out that the conservation effectiveness is still low and larger conservation efforts are urgently needed to maintain the Anatidae populations, especially in wetlands with a lower level protection status. I recommend several protection measures to stop the decline of Anatidae species in wetlands of the Yangtze River flood plain and I called for more research efforts in this area in particularly, but also at a larger scale, the entire East Asian-Australasian Flyway.
In Chapter 6, I synthesized these results and draw conclusions from the preceding chapters, and highlighted the importance of spatial scales when studying the effect of abiotic and biotic variables on animals’ habitat selection. I also propose to modify hydrological regimes, aimed at creating enhanced habitat and improved forage accessibility conditions over the entire wintering period for herbivorous birds species in the Yangtze River flood plain. In summary, this thesis offers a framework for the effects of various variables on habitat selection and population sizes of herbivorous Anatidae species over different spatial scales, and a scientific basis for policy-makers and managers to enhance the efficiency of conservation actions in wetlands along the Yangtze River flood plain and also for similar ecological systems.
Experimental evidence shows the importance of behavioural plasticity and body size under competition in waterfowl
Zhang, Y. ; Prins, H.H.T. ; Versluijs, Martijn ; Wessels, R. ; Cao, L. ; Boer, W.F. de - \ 2015
Wageningen University & Research
competition - waterbirds - behavioral - niche
Effect of conservation efforts and ecological variables on waterbird population sizes in wetlands of the Yangtze River
Zhang, Yong ; Jia, Qiang ; Prins, H.H.T. ; Cao, Lei ; Boer, W.F. de - \ 2015
Scientific Reports 5 (2015). - ISSN 2045-2322
Forage quality and availability, climatic factors, and a wetland's conservation status are expected to affect the densities of wetland birds. However, the conservation effectiveness is often poorly studied. Here, using twelve years' census data collected from 78 wetlands in the Yangtze River floodplain, we aimed to understand the effect of these variables on five Anatidae species, and evaluate the effectiveness of the conservation measures by comparing population trends of these species among wetlands that differ in conservations status. We showed that the slope angle of a wetland and the variation thereof best explain the differences in densities of four species. We also found that the population abundances of the Anatidae species generally declined in wetlands along the Yangtze River floodplain over time, with a steeper decline in wetlands with a lower protection status, indicating that current conservation policies might deliver benefits for wintering Anatidae species in China, as population sizes of the species were buffered to some extent against decline in numbers in wetlands with a higher level protection status. We recommend several protection measures to stop the decline of these Anatidae species in wetlands along the Yangtze River floodplain, which are of great importance for the East Asian-Australasian Flyway.
Avoiding Competition? Site Use, Diet and Foraging Behaviours in Two Similarly Sized Geese Wintering in China
Zhao, Meijuan ; Cao, Lei ; Klaassen, Marcel ; Zhang, Yong ; Fox, Anthony D. - \ 2015
Ardea 103 (2015)1. - ISSN 0373-2266 - p. 27 - 38.
Anser albifrons - Anser fabalis - dietary composition - feeding ecology - interspecific competition
Competition may occur when two species with similar feeding ecologies exploit the same limited resources in time and space. In recent years, the Eastern Tundra Bean Goose Anser fabalis serrirostris and Greater White-fronted Goose Anser albifrons frontalis have increased in wintering numbers at Shengjin Lake, China. To examine the potential for coexistence and possible avoidance strategies, we studied (1) their habitat use, (2) foraging behaviours and (3) diets of birds foraging in mixed- and single-species flocks. Both species extensively exploited sedge meadows, where they showed considerable overlap in spatial distribution and diet. The percentage feeding time and diet of both species were unaffected by the presence of the other. Greater White-fronted Geese appeared diurnal sedge meadow specialists, almost never feeding in other habitats. Eastern Tundra Bean Geese were less selective, exploiting other habitats, which they increasingly exploited at night in mid-winter. The use of alternative habitats and night feeding may have avoided interspecific competition. While the specialised feeding ecology of Greater White-fronted Geese may make them particularly vulnerable to loss of sedge meadow habitat, Eastern Tundra Bean Geese may be able to adjust because of their use of alternative habitats and a less restricted diet.
Individual-area relationship best explains goose species density in wetlands
Zhang, Y. - \ 2015
Use MCMCglmm to analysis the effect of ecological and human disturbance on two goose species densities in wetland.
Individual-area relationship best explains goose species density in wetlands
Zhang, Y. ; Jia, Q. ; Prins, H.H.T. ; Cao, L. ; Boer, W.F. de - \ 2015
PLoS ONE 10 (2015)5. - ISSN 1932-6203 - 11 p.
human disturbance - habitat heterogeneity - mammalian herbivores - population-density - african elephant - forage quality - barnacle geese - body-mass - diversity - selection
Explaining and predicting animal distributions is one of the fundamental objectives in ecology and conservation biology. Animal habitat selection can be regulated by top-down and bottom-up processes, and is mediated by species interactions. Species varying in body size respond differently to top-down and bottom-up determinants, and hence understanding these allometric responses to those determinants is important for conservation. In this study, using two differently sized goose species wintering in the Yangtze floodplain, we tested the predictions derived from three different hypotheses (individual-area relationship, food resource and disturbance hypothesis) to explain the spatial and temporal variation in densities of two goose species. Using Generalized Linear Mixed Models with a Markov Chain Monte Carlo technique, we demonstrated that goose density was positive correlated with patch area size, suggesting that the individual area-relationship best predicts differences in goose densities. Moreover, the other predictions, related to food availability and disturbance, were not significant. Buffalo grazing probably facilitated greater white-fronted geese, as the number of buffalos was positively correlated to the density of this species. We concluded that patch area size is the most important factor determining the density of goose species in our study area. Patch area size is directly determined by water levels in the Yangtze floodplain, and hence modifying the hydrological regimes can enlarge the capacity of these wetlands for migratory birds.
The benefits of being big: effects of body size on energy budgets of three wintering goose species grazing Carex beds in the Yangtze River floodplain
Wang, X. ; Zhang, Y. ; Zhao, M. ; Cao, L. ; Fox, A. - \ 2013
Journal of Ornithology 154 (2013)4. - ISSN 2193-7192 - p. 1095 - 1103.
east dongting lake - herbivorous anatidae - abdominal profiles - anser-erythropus - patch selection - barnacle geese - quality - energetics - allometry - ruminants
Herbivores of different body size vary in food selection because of their different metabolic requirements and abilities to harvest and digest food. Compared with smaller grazers, larger ones require higher food quantity but can tolerate poorer quality. This divergence may also explain habitat partitioning in the distribution of closely related species. By estimating daily energy expenditure (based on observed activity budgets) and energy intake (using the indigestible marker method in food and faeces), we compared the field energy budgets of three wintering herbivorous goose species differing in body size feeding on the same Carex meadows. Throughout the winter, the larger Bean Geese Anser fabalis serrirostris and Greater White-fronted Geese Anser albifrons maintained positive energy budgets grazing lower quality Carex, in contrast to the smaller Lesser White-fronted Geese Anser erythropus which failed to do so and could only maintain positive energy budgets by grazing high-quality Alopecurus, Cynodon and Eleocharis. However, all three species failed to maintain positive energy balance and lost mass in midwinter. These results have important implications for explaining the divergent distribution patterns of these species on their wintering grounds in China.
Declines in the tuber-feeding waterbird guild at Shengjin Lake National Nature Reserve, China - a barometer of submerged macrophyte collapse
Fox, A. ; Cao, L. ; Zhang, Y. ; Barter, M. ; Zhao, M.J. ; Meng, F.J. ; Wang, S.L. - \ 2011
Aquatic conservation: marine and freshwater ecosystems 21 (2011)1. - ISSN 1052-7613 - p. 82 - 91.
yangtze-river basin - vallisneria-spiralis - shallow lakes - poyang lake - birds - impacts - identification - phosphorus - province - swans
1. The Yangtze floodplain is globally unique for its extensive ephemeral wetlands, recharged by summer monsoon precipitation. The annual cycle of inundation and water table recession favours submerged macrophytes, including Vallisneria that overwinters in desiccated substrates as tubers, which provide high-energy winter food for tuber-feeding waterbirds that were formerly abundant in the region. 2. Large declines among the tuber-feeding waterbirds swan goose Anser cygnoides (L.), tundra swan Cygnus columbianus (Ord) and hooded crane Grus monacha Temminck between 2004/2005 and 2009/2010 at Shengjin Lake, Anhui Province, suggest that major changes in food availability have occurred there. 3. Based on observations of feeding behaviour and energy budgets of these species, it was calculated that at least 5.0 and 8.9¿km2 of Vallisneria beds in 2004 and 2005, respectively, would be needed to support observed numbers of these species, compared with less than 1.5¿km2 found in 2009 and 2010. 4. An incomplete macrophyte survey in summer 2000 located at least 7.7¿km2 of Vallisneria beds in the Upper Lake, where none was present during resurveys in 2008 and 2009. Declines in tuber-feeding waterbirds at Shengjin Lake coincide with the disappearance of their submerged macrophyte food plants, possibly as a result of eutrophication since the mid-2000s. 5. Widespread declines and concentration of tuber-eating wintering waterbirds at other sites elsewhere in the Yangtze floodplain may also reflect the local collapse of submerged macrophytes and of ecosystem services that these wetlands provide to the human communities.
Changing distribution and abundance of Swan Goose Anser cygnoides in the Yangtze River floodplain: the likely loss of a very important wintering site
Zhang, Y. ; Cao, L. ; Barter, M. ; Fox, A.D. ; Zhao, M. ; Meng, F. ; Shi, H. ; Jiang, Y. ; Zhu, W. - \ 2011
Bird Conservation International 21 (2011). - ISSN 0959-2709 - p. 36 - 48.
poyang lake - china
Virtually the entire population of the globally ‘Vulnerable’ Swan Goose Anser cygnoides winters in the Yangtze floodplain. Historically, the species was widely distributed throughout the floodplain but now approximately 95% of the population is confined to three closely-situated wetlands in Anhui and Jiangxi Provinces. Recent counts indicate that at one of these sites, Shengjin Lake (in Anhui), a decline of about 10,000–20,000 birds, to about 1,000 currently, has taken place during the last five years. The likely cause of the decline in Swan Goose abundance at Shengjin Lake is the recent decrease in submerged vegetation, particularly tuber-producing Vallisneria which is the species’s main food; this decrease has been linked with the introduction of intensive aquaculture in the main areas used by Swan Geese within the lake. Earlier range contractions in the Yangtze floodplain may also be linked to reductions in submerged vegetation cover at other sites, where intensive aquaculture has also been implicated. Changes in lake hydrology following construction of the Three Gorges Dam may also have adversely affected submerged vegetation productivity. Key information needs for the effective implementation of conservation measures for Swan Goose include an understanding of (1) the fitness consequences of Swan Geese being forced to switch to different foods; (2) how aquaculture can be managed to minimise impacts on submerged vegetation; (3) the impact of changing lake hydrology on key Swan Goose food plants; and (4) the optimal management of wetlands to ensure that adequate food is both produced during the summer period and is available throughout the winter.
Anatidae in eastern China during the non-breeding season: Geographical distributions and protection status
Cao, L. ; Zhang, Y. ; Barter, M. ; Lei, G. - \ 2010
Biological Conservation 143 (2010)3. - ISSN 0006-3207 - p. 650 - 659.
wetlands - birds
Eastern China’s Anatidae are globally important, occurring in large numbers and exhibiting very high diversity; however populations have declined greatly since the 1950s due to habitat loss and degradation, and poaching. To meet the urgent need for up-to-date conservation information, we conducted extensive surveys of the region’s inland and coastal wetlands to collect data on current Anatidae numbers, distributions and key sites. This paper provides information on the non-breeding distributions of 27 species and how these have changed during the last 30 years, and discusses the protection status afforded to Anatidae and their habitats. About 80% of eastern China’s Anatidae occur at inland wetlands, predominantly within the Yangtze River floodplain. Current distributions of most species are different to those of the late-1970s; range contraction, range shift and northward expansion have occurred. Approximately 45% of the total Anatidae population, and high proportions of five globally threatened species populations, were located within National Nature Reserves; coverage could be increased to ca. 65% by inclusion of additional important Anatidae sites within the National Reserve system. However, a number of important issues, such as management skilling and control of land use within reserves, need to be addressed if National Nature Reserves are to provide satisfactory protection for Anatidae. It is also highly desirable that the China National List of Protected Animals include all the relevant Anatidae species on the IUCN Red List to provide a high level of protection for globally threatened species
|Chapter 6. Non-tidal wetlands.
Öquist, M.G. ; Svensson, B.H. ; Groffman, P. ; Bartlett, K.B. ; Boko, M. ; Brouwer, J. ; Canziani, O.F. ; Craft, C.B. ; Laine, J. ; Larson, D. ; Martikainen, P.J. ; Matthews, E. ; Mullie, W. ; Page, S. ; Richardson, C.J. ; Rieley, J. ; Roulet, N. ; Silvola, J. ; Zhang, Y. - \ 1996
In: Climate Change 1995: Impact, adaptions and mitigation of climate change. Scientific-Technical Analyses / Watson, R.T., - p. 215 - 239.