Habitat-dependent changes in vigilance behaviour of Red-crowned Crane influenced by wildlife tourism

The Endangered Red-crowned Crane (Grus japonensis) is one of the most culturally iconic and sought-after species by wildlife tourists. Here we investigate how the presence of tourists influence the vigilance behaviour of cranes foraging in Suaeda salsa salt marshes and S. salsa/Phragmites australis mosaic habitat in the Yellow River Delta, China. We found that both the frequency and duration of crane vigilance significantly increased in the presence of wildlife tourists. Increased frequency in crane vigilance only occurred in the much taller S. salsa/P. australis mosaic vegetation whereas the duration of vigilance showed no significant difference between the two habitats. Crane vigilance declined with increasing distance from wildlife tourists in the two habitats, with a minimum distance of disturbance triggering a high degree of vigilance by cranes identified at 300 m. The presence of wildlife tourists may represent a form of disturbance to foraging cranes but is habitat dependent. Taller P. australis vegetation serves primarily as a visual obstruction for cranes, causing them to increase the frequency of vigilance behaviour. Our findings have important implications for the conservation of the migratory red-crowned crane population that winters in the Yellow River Delta and can help inform visitor management

Human activities accelerated the degradation of saline seepweed red beaches by amplifying top‐down and bottom‐up forces

Salt marshes dominated by saline seepweed (Suaeda heteroptera) provide important ecosystem services such as sequestering carbon (blue carbon), maintaining healthy fisheries, and protecting shorelines. These salt marshes also constitute stunning red beach landscapes, and the resulting tourism significantly contributes to the local economy. However, land use change and degradation have led to a substantial loss of the red beach area. It remains unclear how human activities influence the top‐down and bottom‐up forces that regulate the distribution and succession of these salt marshes and lead to the degradation of the red beaches. We examined how bottom‐up forces influenced the germination, emergence, and colonization of saline seepweed with field measurements and a laboratory experiment. We also examined whether top‐down forces affected the red beach distribution by conducting a field survey for crab burrows and density, laboratory feeding trials, and waterbird investigations. The higher sediment accretion rate induced by human activities limited the establishment of new red beaches. The construction of tourism facilities and the frequent presence of tourists reduced the density of waterbirds, which in turn increased the density of crabs, intensifying the top‐down forces such as predators and herbivores that drive the degradation of the coastal red beaches. Our results show that sediment accretion and plant–herbivory changes induced by human activities were likely the two primary ecological processes leading to the degradation of the red beaches. Human activities significantly shaped the abundance and distribution of the red beaches by altering both top‐down and bottom‐up ecological processes. Our findings can help us better understand the dynamics of salt marshes and have implications for the management and restoration of coastal wetlands

Burrow ambient temperature influences Helice crab activity and availability for migratory Red-crowned cranes Grus japonensis

© 2020 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd For migratory birds that specialize on particular benthic macroinvertebrate species, the timing of migration is critical since prey availability may be temporally limited and a function of local ambient temperature. Hence, variation in local ambient temperature can influence the diet composition of migrant birds, and, consequently, they may be constrained by which stopover and wintering sites they are able to utilize during periods of colder temperatures. Here, we use fecal analysis, observer-based population counts, digital video recordings, and temperature data to test five predictions regarding the influence of local ambient temperature on the activity and availability of mudflat crabs—a key prey resource at three staging/wintering sites in eastern China, for migratory Red-crowned cranes (Grus japonensis) and how this subsequently influences crane diet and use of wetland sites. Pearson's correlations and generalized linear models revealed that mudflat crabs became significantly more surface active with increasing burrow ambient temperature. Piecewise regression analysis revealed that crab surface activity was largely limited to a burrow ambient temperature threshold between 12 and 13℃ after which activity significantly increased. Crab activity declining temporally during the crane's autumn migration period but increased during spring migration. Crabs accounted for a significant proportion of crane diet at two of three sites; however, the frequency of crab remains was significantly different between sites, and between autumn and spring migration. Analyses of crane count data revealed a degree of congruence between the migration timing of Red-crowned cranes with periods of warmer ambient temperature, and a significant, positive correlation between the percentage of crab remains in crane feces and site ambient temperature. Collectively, our data suggest that temperature-related mudflat crab activity may provide an important time window for migratory Red-crowned cranes to utilize critical stopover sites and the crabs’ food resources

Rapid reclamation and degradation of suaeda salsa saltmarsh along coastal china’s northern yellow sea

Suaeda salsa saltmarshes are an important coastal wetland habitat of China’s northern Yellow Sea, which plays a critical role in sequestering carbon (blue carbon), protecting shorelines, maintaining biodiversity, and has substantial economic value (e.g., ecotourism). However, the area of S. salsa has been rapidly declining due to several different threats from reclamation and invasive species that impact its natural succession. Here, we map the changes in the distribution of the S. salsa saltmarshes along the northern Yellow Sea of China (NYSC) at 5-year intervals by applying the supervised maximum likelihood method to analyze Landsat images from 1988 to 2018 and investigate the potential impact of three important factors on habitat change by analyzing the temporal changes in S. salsa saltmarshes with other land covers. S. salsa saltmarsh areas have decreased by 63% (264 km2 ha to 99 km2 ), and the average loss of S. salsa saltmarshes was 5.5 km2/year along the NYSC over the past three decades. There have been many dramatic declines in the two main distribution areas of S. salsa saltmarshes with a 77% loss of habitat area in Liaodong Bay (from 112 km2 to 26 km2) and a 52% loss in the Yellow River Delta wetland-Guangli-Zhima estuarine wetland (from 137 km2 to 65 km2 ). Land reclamation is the most important impact factor in the loss of S. salsa saltmarshes, while there have been limited effects of natural succession and smooth cordgrass (Spartina alterniflora) invasion. In light of the important ecological services and economic value of the S. salsa habitat, emergency conservation actions (e.g., habitat restoration, strictly supervision) are needed to limit the rapid habitat loss, which should include the immediate cessation of extensive land reclamation along the NYSC

Birds as indicators of change in the freshwater ecosystems of Botswana

Freshwater ecosystems support highly biodiverse plant and animal populations and provide crucial ecosystem services to human communities. Despite this importance, these systems are being degraded faster than terrestrial or marine environments, resulting in large global declines in freshwater biodiversity. To track such environmental change, birds are often used as indicator species. I focused on tracking changes in significant waterbird breeding colonies, rivers and internationally listed wetlands in Botswana facing a wide range of threats. I identified that riparian bird communities along the Chobe River were more biodiverse in sites with the presence of large herbivores, highlighting the direct and indirect relationships between these seemingly unconnected taxa. Using a drone, I explored the relationships between waterbird breeding and river levels and inundation. Drone imagery on the Chobe River provided comprehensive data on the reproductive success, size and composition of the Kasane waterbird breeding colony, which were linked to river levels and inundation, while citizen science collected abundance data helped identify a threshold river level to support large waterbird breeding colonies. This underlined the importance of river flows for waterbird populations and the potential for the breeding of waterbirds to inform river management. Similarly in the Okavango Delta, citizen science data highlighted positive relationships between waterbird abundance and river flows, but there were indications of long-term declines in waterbird abundances. River flows were again important for waterbird breeding, with key waterbird breeding colonies located in areas experiencing moderate to high flood frequencies. I also developed a semi-automated counting technique for investigating colony sizes with a drone, negating the need to physically enter a colony or manually count imagery, saving time in image processing and ensuring researcher safety. Finally, I investigated the potential effects of foraging at landfill on the marabou stork. Plastics formed a significant proportion of marabou regurgitant while trace metal concentrations in feathers were higher than in naturally foraging populations, indicating potential deleterious impacts. My work highlighted the value of riparian bird communities, predominantly waterbirds, as indicators of change, reflecting herbivore population structures, land use alterations and changes in freshwater flows and inundation

Towards adaptive management of high-altitude grasslands: Ingula as a case study

Includes bibliographical referencesEastern high - altitude grasslands of South Africa are centres for endemism and harbour fauna and flora of regional and international conservation concern. This area also provides important ecological services such as provision of water to communities downstream. Sweet and sour veld support beef livestock farming during summer months. The aesthetic beauty of the region makes the area a prime tourist destination too. More recently the area is becoming a target of other agricultural projects such man - made forests. Other new developments that need to be mitigated against are development of renewable energy projects such as pumped water schemes to generate electricity or wind farms. Additional habitat is lost when these projects are connected to the national grid. In this thesis, I use bird data and vegetation data to compare, contrast and suggest management tools to manage this area. I present data that I collected at Ingula Pumped Storage Scheme spanning five years from the beginning of the construction of the scheme to near its completion in 2012 as a case study to manage similar habitats. Chapter 1 presents a brief overview of ecological importance of this area and the history behind the construction of pumped storage scheme at Ingula. A literature review in Chapter 2 investigates management tools to manage these grasslands for avian diversity. Fire and grazing is a key management tool cited to make habitat suitable for birds. While few studies from this type of grassland exist, studies from outside South Africa suggest that fire and grazing supplement each other as management tool to make habitat suitable for species with contrasting ecological requirements. A mosaic of grass heights and cover across the landscape translates to species habitat suitability. Chapter 3 explores species richness through years, seasons and impact of grass height and cover on bird species richness. Species richness was highest in summer suggesting that management should make habitat for species suitable in summer when most priority species are likely to use the habitat. The main disadvantage of using bird species richness is that fieldworkers must know their species well. Secondly, use of species richness must be treated with caution because this method does not account for species detectability in time and in space. In Chapter 4 I use hierarchical distance sampling models which take into account both the detection and the biological process. To demonstrate this I used common grassland bird species which can easily be identified during monitoring. The downside of this approach is that because these species are common and therefore occur almost everywhere, they may not easily respond to lack of habitat heterogeneity. The technical disadvantage of using this method is to accurately allocate species to within distance bands, making this method challenging for fieldworkers. Chapter 5 presents random plot occupancy which records only detection - nondetection of birds during repeated plot surveys. This method accounts for observational and biological processes too and in addition implements rigorous statistical inferences to predict how birds respond to habitat variable s as influenced by management decision on fire and grazing. Finally, adverse weather conditions may hamper surveying all plots in some years. Through occupancy modelling it is possible to predict species occupancy on plots that were not surveyed during some years and finally this method has been improved to include rare species. This is my preferred method to monitor management effect on habitat suitability for birds at Ingula. Adaptive management, a pillar of which is adaptive monitoring is a new paradigm shift in conservation. In Chapter 6, I capture interactions between burning and grazing and effects on grass height and cover to predict habitat suitability for birds including large threatened Ingula birds using a simulation models. This model sets a stage for implementing adaptive management through experimental plots to capture a set of management uncertainties regarding the use of fire and grazing as management tools. Chapter 7 summarizes the thesis and acknowledges that Ingula consists of other equally important habitat and ecosystem such as cool moist mountain forest and matrix of grassland wetland that equally need to be conserved

Ecological baseline surveys of Lake Bisina, Lake Opeta, Lake Mburo and Nakivali wetlands systems

Wetlands cover about 30,000 km2 of Uganda’s land area and are considered to be important ecosystems, which contribute considerably to the national economy and rural livelihoods. However, these important ecosystems are currently under increasing pressure due to factors such as population growth, economic reforms, climate change and the desire for increase in per capita income and other pressures of the development process. Threats include among others uncontrolled conversion of the wetlands into agricultural areas and unplanned developments and wetland uses which may have adverse effects on the capacity of the wetlands to perform natural functions. In order to address these threats, there is need to promote wise use of the wetland ecosystem. This can be done using existing guidelines or by developing other guidelines that will assist the various districts in developing ordinances and bye-laws to regulate the use of wetlands in their areas of jurisdictio

Evaluation of potential habitat with an integrated analysis of a spatial conservation strategy for David’s deer, Elaphurus davidians

How to assess the potential habitat integrating landscape dynamics and population research, and how to reintroduce animals to potential habitats in environments highly human disturbed are still questions to be answered in conservation biology. According to behavioral research on Elaphurus davidians, we have developed a suitability index and a risk index to evaluate the potential habitats for the deer. With these indices, we conducted two transect assessments to evaluate the gradient change of the target region. Then, taking rivers as border lines, we tabulated the forest areas, high grassland area and total area and then compared the forest and high grassland area in each subregion. Furthermore, we computed the land use transfer matrix for the whole Yancheng coast during 1987–2000. We also computed human modified index (HMI) in six subregions. Lastly with a geographical information system support we obtained the spatial distribution of the indices and evaluation of the whole potential habitats from a neighborhood analysis. The transect assessment showed that the suitability of the coastal area was higher than that of the inland area for the deer, while the southern area was higher than the northern. Landscape metrics and HMI analysis showed that different landscape patterns and different anthropogenic disturbance existed within the region, and the increasing human disturbance was the key factor causing the pattern dynamics. The evaluation of potential habitats showed that there was an estimated carrying capacity of no more than 10,000 for David’s deer reintroduction into the natural area. Also the reintroduction strategy was discussed. This integrated approach linked the population research and the landscape metrics, and the dataset with different scale; thus, it is an approach likely to be useful for the protection of other large animal in a landscape highly disturbed by humans