Whole‐community facilitation by beaver: ecosystem engineer increases waterbird diversity

相似文献   

The value of small,natural and man‐made wetlands for bird diversity in the east Colombian Piedmont

相似文献   

Relationships between breeding waterbird abundance,diversity, and clear water status after the restoration of two shallow nutrient‐rich Danish lakes

1. Breeding waterbird communities have suffered globally from the effects of anthropogenic changes in water quality (especially nutrient enrichment) in recent decades, but few studies have demonstrated the positive effects of restorative actions.
2. Annual breeding waterbird surveys in the period 1977–2005 at two restored southern Danish lake basins (combining nutrient load reduction and biomanipulation) showed an up to five‐fold increase in abundance, and considerable changes in species richness and diversity, following restoration to clear water status in both lakes.
3. Parallel surveys at a third lake, which retained clear water quality throughout, offering a form of natural ‘control', showed no such changes over the same time period.
4. Consistent relationships between breeding waterbird abundance, species richness, and diversity with measures of water clarity (Secchi disc depth, chlorophyll a, and suspended matter) suggest that water clarity mainly drives the relationship; inverse relationships between these measures and total nitrogen and phosphorus were less consistent than for water clarity.
5. The results suggest that an improvement in water clarity plays a key role in restoring breeding waterbird communities and suggest that breeding waterbirds can be indicators of the success of lake restoration projects, but more studies are needed to confirm their wider utility under a variety of conditions.

     

Restoration of a small‐scale forest wetland in a Belgian nature reserve: a discussion of factors determining wetland vegetation establishment

• 1. The main aim of this restoration attempt within a nature reserve was to recreate sustainable conditions for wetland species, particularly aquatic plants.
• 2. In the process of restoration, two phases of activity were distinguished: a pre‐restoration phase, during which information on land‐use history and past vegetation was collected and used to establish clear restoration goals; and a restoration phase for stimulating germination and establishment of target species originating from the soil seed bank and species pool.
• 3. Within the first year of the study, pond digging allowed the establishment of extremely rare native species that react positively to mudflat creation and standing water availability. The results of this experiment indicate that pond digging can be a very suitable technique for re‐establishing aquatic and wetland vegetation, providing that the site is well chosen.
• 4. An essential prerequisite for successful restoration is a study of the past vegetation of the target site and its surroundings. This work illustrates the importance of past vegetation in affecting current restoration success and provides an example of how restoration projects benefit from knowledge and understanding of both historical and present conditions.

Copyright © 2004 John Wiley & Sons, Ltd.     

Managing threats and restoring wetlands within catchments of the Great Barrier Reef,Australia

1. The catchments of the Great Barrier Reef (GBR) in Australia include more than one million ha of wetlands, which help to sustain the health and resilience of the reef.
2. This article reviews the status, values, and threats of wetlands in the GBR catchments, as well as the management, protection, and challenges and opportunities for their restoration and rehabilitation.
3. At present, wetlands in the GBR catchments have low rates of area loss and are generally well protected; however, they face major management challenges owing to the intensive land use of the catchments, especially for grazing, agriculture, horticulture, and mining. Major threats to these wetlands include water pollution, invasive species, changes in hydrology, and increasing temperature and salinity resulting from climate change.
4. In recent years wetlands have been considered primarily for their role in improving water quality to ameliorate contaminated terrestrial run‐off to the GBR, with little attention given to their intrinsic value and other ecosystem services.
5. Financial opportunities for wetland restoration in addition to government‐funded schemes include water pollution offsets, payment for ecosystem services, and nitrogen markets.
6. Wetlands need to be protected, managed, and restored for the ecosystem services that they provide to the GBR, but also for their intrinsic value as significant features of coastal landscapes.

     

Land use surrounding wetlands influences urban populations of a freshwater turtle

1. Urbanization is one of the most influential land use changes globally and continues to affect wetland ecosystems and their biota. Freshwater turtles, which rely on both terrestrial and aquatic habitats to complete their life cycles, are one of the most endangered vertebrate groups, with approximately 60% of species threatened. Although habitat alteration caused by urbanization is recognized as one of the main threats to freshwater turtles, there is a paucity of studies quantifying the effects of terrestrial habitat change on turtle populations.
2. The aim of this study was to determine how terrestrial land use change, associated with urbanization, influences the viability of freshwater turtle populations. Thirty‐three wetlands were sampled for the southwestern snake‐necked turtle (Chelodina colliei Gray, 1856) (Chelidae) between October 2016 and February 2017 within a region of continuing urban intensification. Land use and habitat types were classified at the aquatic–terrestrial interface and within a 300‐m band around each wetland. Generalized linear mixed models were used to identify the land use variables that best explained the relative abundance of C. colliei.
3. Turtle abundance and population structure varied widely among wetlands. The percentage of residential land use, and the presence and accessibility of fringing native vegetation, was positively associated with the relative abundance of C. colliei. The association with residential land use may be an artefact of historical land use, whereas the association with native vegetation is probably because adjacent vegetation provides connectivity with suitable nesting sites, and thus facilitates increased recruitment.
4. This study shows how the modification of terrestrial habitat around wetlands may directly influence the population viability of freshwater turtles. Protection and restoration of native vegetation fringing urban wetlands is crucial to support the viability of remnant freshwater turtle populations.

     

Linking vegetation patterns,wetlands conservation,and ecosystem services provision: From publication to application

1. Natural wetlands emerge as the best sites to preserve the diversity of aquatic and riparian vegetation; however, especially in the lowlands, pristine wetlands and aquatic ecosystems have almost completely disappeared through land reclamation and agricultural development. Actions are needed, therefore, to maintain and recreate a wide network of wetlands able to preserve adequate levels of vegetation diversity.
2. Focusing on a complex wetland system located in an overexploited plain, the article entitled ‘The importance of being natural in a human‐altered riverscape: Role of wetland type in supporting habitat heterogeneity and the functional diversity of vegetation’, published in 2016 in Aquatic Conservation: Marine and Freshwater Ecosystems (AQC) explored the role of wetland origin and hydrology as the main drivers of physical and vegetation functional diversity, following a hierarchical sampling approach.
3. The main results reinforced the key contribution of natural sites in maintaining vegetation diversity in heavily impaired riverine contexts, suggesting a direct effect of the interannual and seasonal dynamics of water‐level variations in the observed vegetation patterns.
4. The article offered an important contribution to our knowledge of vegetation patterns in wetlands, partly attributed to the innovative functional, hierarchical approach applied which is able to guarantee reliable data on the distribution patterns of physical heterogeneity and wetland vegetation.
5. The findings of the article have been applied and adopted in a series of technical handbooks designed, inter alia, to support the monitoring programmes of habitats of community interest or vegetation of relevance for aquatic biodiversity conservation. In addition, this article has helped to raise awareness of the essential roles played by wetlands in agricultural landscapes and has emphasized the need for a better synergy between the European Habitats Directive and the Water Framework Directive. Several ecological recovery projects have been funded in line with the results described in the AQC article.

     

Salinity tolerance during early development of threatened Murray hardyhead (Craterocephalus fluviatilis) to guide environmental watering

1. The worldwide reduction in wetlands has led to the large‐scale decline of wetland‐dependent species. In Australia, to redress some of the decline, partial restoration of the hydrology of a small number of wetlands has been attempted using allocations of environmental water.
2. A common goal of the watering is the maintenance and enhancement of native fish communities, which historically have included populations of the salt tolerant Murray hardyhead (Craterocephalus fluviatilis), a small, short‐lived fish, endemic to the lower Murray–Darling Basin.
3. Despite the addition of environmental water to several sites at which the species is known to persist, populations continue to decline. This decline is, at least in part, suspected to be a consequence of salinities that conflict with the breeding ecology and survival of early life stages.
4. Here the effect of salinity on egg hatch rate and the upper salinity tolerance of larval and juvenile Murray hardyhead was determined under laboratory conditions. It was found that eggs were vulnerable to elevated salinities, whereas juveniles were capable of tolerating salinities up to 105 ppt.
5. Based on the results of the experiment, brackish wetlands managed for Murray hardyhead should be maintained, where possible, between 12 and 45 ppt. Such a salinity regime will necessitate less intensive management of salinity, and a reduced volume of environmental water, providing both environmental and fiscal benefits. The research highlights the benefits of investment in targeted research.

     

Contrasting influences of inundation and land use on the rate of floodplain restoration

1. This study examined the assisted natural restoration of native vegetation in an Australian floodplain wetland where flows were reinstated and the river was reconnected to the floodplain, following cessation of agricultural cultivation.
2. Extant vegetation was surveyed three times during an inundation event at plots with different land‐use histories.
3. Restoration rate was more influenced by past land use than long‐term inundation frequency and success decreased with antecedent land‐use intensity. Prolonged land‐use history (>3 years cultivation) restricted restoration success. Sites with longer cultivation histories tended to have fewer aquatic species, more terrestrial species and exotic species. For example, amphibious responders with floating leaves were found only in reference plots and less frequently in farmed treatment plots. In this scenario, increased persistence of exotics and dryland species suggested alternative trajectories. Fields with a short land‐use history (1–3 years of clearing and cultivation) resembled undisturbed floodplain communities, consistent with a ‘field of dreams’ hypothesis.
4. Although river–floodplain reconnections can restore wetlands, legacy effects of past land use may limit the pace and outcomes of restoration.

     

Brazilian wetlands: their definition,delineation, and classification for research,sustainable management,and protection

相似文献   

The characterization and classification of the Black River Upper Morass,Jamaica, using the three‐parameter test of vegetation,soils and hydrology

• 1. The characterization and classification of the Black River Upper Morass was conducted using the criteria of the three‐parameter test for vegetation, soils and hydrology at 14 sites within the study area.
• 2. The Upper Morass exhibited 71% hydrophytic vegetation typical of wetlands (vascular and non‐vascular plants including Cladium jamaicense, Phragmites australis, Typha angustifolia and Sagittaria lancifolia) and 29% vegetation atypical of wetlands.
• 3. The Upper Morass is classified as a Palustrine System with sub‐classes of Aquatic Bed and Persistent Emergent Wetland.
• 4. The presence throughout the Upper Morass of monoculture stands of the invasive species Eichhornia crassipes and Typha domingensis, which are known to invade disturbed or partially drained wetlands, confirmed that the study area was a disturbed ecosystem.
• 5. The Upper Morass exhibited hydric (flood‐water and groundwater) soils, which, in association with its temporarily flooded and saturated wetland hydrology, indicated that it is groundwater‐driven.
• 6. Application of the three‐parameter test indicated a linkage between the functions of the Upper Morass and the Lower Morass, and thus a need for conservation of the Black River Morass System as a single unit rather than two independent wetlands. Two key instruments of conservation will be further detailed ecological assessments and the implementation of a management plan.

Copyright © 2006 John Wiley & Sons, Ltd.     

Desktop classification of inland wetlands for systematic conservation planning in data‐scarce countries: mapping wetland ecosystem types,disturbance indices and threatened species associations at country‐wide scale

相似文献   

Genetic structuring among populations of the great egret,Ardea alba egretta,in major Brazilian wetlands

相似文献   

Integrating freshwater wetland science into planning for Great Barrier Reef sustainability

1. The paper ‘Biodiversity values of remnant freshwater floodplain lagoons in agricultural catchments: evidence for fish of the Wet Tropics bioregion, northern Australia’, published in Aquatic Conservation: Marine and Freshwater Ecosystems in 2015, has contributed in several ways to the integration of freshwater wetland science within new catchment management policies and practices for Great Barrier Reef (GBR) sustainability.
2. The Tully–Murray biodiversity study developed novel protocols to sample larval, juvenile, and adult fish life‐history stages in floodplain lagoons using a combination of boat‐based backpack electrofishing and fyke netting. In addition, hydrological and hydrodynamic models were applied in a completely new way to quantify the timing, extent, and duration of water connectivity across floodplain streams, cane drains, and wetlands. Combining the two novel approaches enabled an analysis of lagoon fish assemblage patterns in relation to environmental gradients, especially floodplain hydrology, connectivity patterns, and measures related to agricultural land use.
3. In demonstrating the importance of different levels of connectivity for different biodiversity outcomes in freshwater floodplain lagoons of the Tully–Murray catchment, the subject paper established that floodplain connectivity needs to be taken into consideration in wetland management practices.
4. The timing of the subject publication was fortuitous. It coincided with the preparation of the evidence‐based 2017 Scientific Consensus Statement on land‐based water quality impacts on the GBR. As one of the few freshwater wetland ecology publications for the catchments of the GBR at that time, this paper played an important role in demonstrating freshwater wetland values, fish conservation options, and management imperatives to sustain wetland ecological health and services in GBR catchments.
5. By advancing the understanding of factors driving biodiversity patterns, and the importance of connectivity and ecohydrological processes in freshwater floodplain wetlands of the GBR catchment, the Tully–Murray study helped to drive new policy directives for the protection and restoration of catchment, floodplain, and estuary functions, and connectivity, now embedded in the Reef 2050 Long‐Term Sustainability Plan 2018, an overarching strategy for managing the GBR over the next 35 years, and complementary Queensland environmental legislation.

     

Willow (Salix spp.) and aspen (Populus tremula) regrowth after felling by the Eurasian beaver (Castor fiber): implications for riparian woodland conservation in Scotland

• 1. A proposed trial reintroduction of the Eurasian beaver (Castor fiber L.) to Scotland has recently been approved (May 2008). A previous proposal was turned down by the licensing authority, partly over the perceived risks to woodland within a Special Area of Conservation.
• 2. This paper presents data on two years of willow (Salix spp.) and aspen (Populus tremula L.) regrowth following tree felling by captive beavers within two large semi‐natural enclosures in eastern Scotland. Both willow and aspen are highly preferred by beavers.
• 3. Regrowth of willow stems was quantified from cut stumps, felled logs and partially severed (‘incompletely felled’) trees, and compared with growth of stems in the canopies of untouched willows.
• 4. Maximum annual regrowth was observed in incompletely felled trees, followed by cut stumps and then unfelled control trees. Mean regrowth rates were ca 18 m regrowth per metre of measured tree section per year in incompletely felled trees. This was approximately 12 times more annual regrowth than that observed in unfelled trees, despite apparently selective browsing of the regrowth of incompletely felled trees by roe deer.
• 5. Although incompletely felled willows represent a relatively small component of felling activity (9% of all felled willow), they contribute disproportionately to the biomass of beaver‐engineered riparian woodlands, creating a more multi‐layered habitat structure.
• 6. Willow regrowth in inundated areas was avoided by deer, and harvesting of regrowth by beavers was rare.
• 7. Significant regrowth from 11 stumps of aspen in 2 years post‐felling occurred by suckering, with 85 suckers of mean height 2.1 m being recorded, all of which were subsequently avoided by browsing deer and beavers.
• 8. These data suggest that rapid regeneration of willow and aspen will occur in riparian woodlands in the event of major felling activity by Eurasian beaver, even in the presence of low to moderate levels of roe deer browsing, and that the conservation status of both these trees or the wider habitats that they form would not be threatened by a well planned and managed reintroduction of beavers to Scotland.

Copyright © 2008 John Wiley & Sons, Ltd.     

Assessing the extent to which temporal changes in waterbird community composition are driven by either local,regional or global factors

相似文献   

Stable isotope ratios of egg albumen of three waterbird species nesting in the Colorado River Delta indicate differences in foraging ground and isotopic niche breadth

相似文献   

Wetland edges as peak refugia from an introduced piscivore

相似文献   

Managed and natural inundation: benefits for conservation of native fish in a semi‐arid wetland system

相似文献   

Coastal wetlands of Victoria,south‐eastern Australia: providing the inventory and condition information needed for their effective management and conservation

相似文献