Description:
Lake sediments constitute natural archives of past environmental changes. Historically, research has focused mainly on generating regional climate records, but records of human impacts caused by land use and exploitation of freshwater resources are now attracting scientific and management interests. Long-term environmental records are useful to establish ecosystem reference conditions, enabling comparisons with current environments and potentially allowing future trajectories to be more tightly constrained. Here we review the timing and onset of human disturbance in and around inland water ecosystems as revealed through sedimentary archives from around the world. Palaeolimnology provides access to a wealth of information reflecting early human activities and their corresponding aquatic ecological shifts. First human impacts on aquatic systems and their watersheds are highly variable in time and space. Landscape disturbance often constitutes the first anthropogenic signal in palaeolimnological records. While the effects of humans at the landscape level are relatively easily demonstrated, the earliest signals of humaninduced changes in the structure and functioning of aquatic ecosystems need very careful investigation using multiple proxies. Additional studies will improve our understanding of linkages between human settlements, their exploitation of land and water resources, and the downstream effects on continental waters.
Description:
Lake sediments constitute natural archives of past environmental
Description:
Lake sediments constitute natural archives of past environmental changes. Historically, research has focused mainly on generating regional climate records, but records of human impacts caused by land use and exploitation of freshwater resources are now attracting scientific and management interests. Long-term environmental records are useful to establish ecosystem reference conditions, enabling comparisons with current environments and potentially allowing future trajectories to be more tightly constrained. Here we review the timing and onset of human disturbance in and around inland water ecosystems as revealed through sedimentary archives from around the world. Palaeolimnology provides access to a wealth of information reflecting early human activities and their corresponding aquatic ecological shifts. First human impacts on aquatic systems and their watersheds are highly variable in time and space. Landscape disturbance often constitutes the first anthropogenic signal in palaeolimnological records. While the effects of humans at the landscape level are relatively easily demonstrated, the earliest signals of humaninduced changes in the structure and functioning of aquatic ecosystems need very careful investigation using multiple proxies. Additional studies will improve our understanding of linkages between human settlements, their exploitation of land and water resources, and the downstream effects on continental waters.
Description:
Lake sediments constitute natural archives of past environmental
Description:
Evaluation of visual quality is essentially a multi-dimensional and multi-sensory experience of landscape assessment. Visual quality refers to the character, condition and quality of lakes/wetlands. It involves perceiving, preferring and valuing the visual quality by the public. Visual quality is an outcome of the perceptual, cognitive and emotional processes in response to visual stimuli of a lake environment. Visual quality therefore is dependent upon the perceptual and structural aspects of perceived scenes of wetlands. Visual assessment, an evaluating process of gaining non-material or intangible benefits by people from ecosystems, through spiritual enrichment, cognitive development, self-reflection, recreation, and aesthetic experiences, has now become one of significant research areas under cultural components of ecosystem services. Public perception in such studies is composed from both the objective and subjective elements of human–landscape interactions. However, it is still a matter of debate whether subjective–objective realities are dichotomous or supplementary to enhancing the quality of human experiences in natural settings. In fact, much research considers them as inseparable and integral parts of landscape perception, despite the tendency for disintegrating landscapes into their constituent components. There is a fundamental theoretical divergence of opinions over the question whether a landscape has an intrinsic or ‘objective’ beauty, which may be in some ways measurable or comparable, or whether beauty is a value that can be only attributed subjectively to an area or a specific landscape.
Description:
Evaluation of visual quality is essentially a multi-dimensional and multi-sensory experience of landscape assessment. Visual quality refers to the character, condition and quality of lakes/wetlands. It involves perceiving, preferring and valuing the visual quality by the public. Visual quality is an outcome of the perceptual, cognitive and emotional processes in response to visual stimuli of a lake environment. Visual quality therefore is dependent upon the perceptual and structural aspects of perceived scenes of wetlands. Visual assessment, an evaluating process of gaining non-material or intangible benefits by people from ecosystems, through spiritual enrichment, cognitive development, self-reflection, recreation, and aesthetic experiences, has now become one of significant research areas under cultural components of ecosystem services. Public perception in such studies is composed from both the objective and subjective elements of human–landscape interactions. However, it is still a matter of debate whether subjective–objective realities are dichotomous or supplementary to enhancing the quality of human experiences in natural settings. In fact, much research considers them as inseparable and integral parts of landscape perception, despite the tendency for disintegrating landscapes into their constituent components. There is a fundamental theoretical divergence of opinions over the question whether a landscape has an intrinsic or ‘objective’ beauty, which may be in some ways measurable or comparable, or whether beauty is a value that can be only attributed subjectively to an area or a specific landscape.
Description:
In the 12 years since Dudgeon et al. (2006) reviewed major pressures on freshwater ecosystems, the biodiversity crisis in the world's lakes, reservoirs, rivers, streams and wetlands has deepened. While lakes, reservoirs and rivers cover only 2.3% of the Earth's surface, these ecosystems host at least 9.5% of the Earth's described animal species. Furthermore, using the World Wide Fund for Nature's Living Planet Index, freshwater population declines (83% between 1970 and 2014) continue to outpace contemporaneous declines in marine or terrestrial systems. The Anthropocene has brought multiple new and varied threats that disproportionately impact freshwater systems. We document 12 emerging threats to freshwater biodiversity that are either entirely new since 2006 or have since intensified: (i) changing climates; (ii) e-commerce and invasions; (iii) infectious diseases; (iv) harmful algal blooms; (v) expanding hydropower; (vi) emerging contaminants; (vii) engineered nanomaterials; (viii) microplastic pollution; (ix) light and noise; (x) freshwater salinisation; (xi) declining calcium; and (xii) cumulative stressors. Effects are evidenced for amphibians, fishes, invertebrates, microbes, plants, turtles and waterbirds, with potential for ecosystem-level changes through bottom-up and top-down processes. In our highly uncertain future, the net effects of these threats raise serious concerns for freshwater ecosystems. However, we also highlight opportunities for conservation gains as a result of novel management tools (e.g. environmental flows, environmental DNA) and specific conservation-oriented actions (e.g. dam removal, habitat protection policies, managed relocation of species) that have been met with varying levels of success. Moving forward, we advocate hybrid approaches that manage fresh waters as crucial ecosystems for human life support as well as essential hotspots of biodiversity and ecological function. Efforts to reverse global trends in freshwater degradation now depend on bridging an immense gap between the aspirations of conservation biologists and the accelerating rate of species endangerment.
Description:
Lachnagrostis filiformis (frost) Trin, commonly known as fairly grass, is a native grass that has recently become a major concern for rural communities.