Proposed Development Sites Research Articles

Corrigendum to: Estimates of abundance and apparent survival of coastal dolphins in Port Essington harbour, Northern Territory, Australia

Context Three dolphin species occur in coastal waters of monsoonal northern Australia: the Australian snubfin (Orcaella heinsohni), humpback (Sousa sp.) and the bottlenose (Tursiops sp.). Their overall population size and trends are poorly known, and their conservation status has been difficult to resolve, but can be expected to deteriorate with likely increased development pressures. Aims We sought to provide an estimate of abundance, and apparent survival, of the three dolphin species at the largely undeveloped harbour of Port Essington (325km2), Northern Territory, with repeated sampling over a 2.9-year period. Given increasing obligations to undertake population assessments for impact studies at proposed development sites, we assess the strengths and limitations of a systematic sampling program.

Multibeam Acoustic Detection of Fish and Water Column Targets at High-Flow Sites

The potential rapid development of tidal energy and accompanying structures in the coastal waters in several regions of Canada, and the world, will require subsurface sampling tools to monitor and evaluate the biological and environmental effects of this new industry. Proposed development sites are characterized by large tidal ranges, strong tidal flows, extreme turbulence, and in some cases sediment-laden water restricting visibility, imposing monitoring challenges. Turbulence-induced acoustic backscatter typically occurs in the top 10–20 m, but can extend from the surface to bottom during some phases of the tide. In Minas Passage, turbulence accounted for 78 % of the total water column backscatter making the separation of fish difficult if not impossible at times. In this paper, we examine operational capabilities of two high-frequency multibeam sonars to meet these monitoring challenges in the nearshore high-flow shallow coastal waters (1–100 m). Observations from proposed sites are used to illustrate the challenges as well as the advantages, and limitations, of multibeam sonars compared to conventional split beam technology in strong tidal currents and turbulent waters. Acoustic multibeam hardware necessary to meet the monitoring demands is currently available, but the processing and analytical software required to advance their application is insufficient to meet the requirements for effects and impact monitoring. It is anticipated that the required advancements will be available within the next 5 years. Challenges associated with equipment deployment, power supply, and communications are also discussed.

Estimates of abundance and apparent survival of coastal dolphins in Port Essington harbour, Northern Territory, Australia

Context Three dolphin species occur in coastal waters of monsoonal northern Australia: the Australian snubfin (Orcaella heinsohni), humpback (Sousa sp.) and the bottlenose (Tursiops sp.). Their overall population size and trends are poorly known, and their conservation status has been difficult to resolve, but can be expected to deteriorate with likely increased development pressures. Aims We sought to provide an estimate of abundance, and apparent survival, of the three dolphin species at the largely undeveloped harbour of Port Essington (325 km2), Northern Territory, with repeated sampling over a 2.9-year period. Given increasing obligations to undertake population assessments for impact studies at proposed development sites, we assess the strengths and limitations of a systematic sampling program. Methods We used photo-identification data collected during systematic boat-based transect surveys undertaken from 2008 to 2010 and Pollock’s robust capture–recapture design model. Key results Total abundance estimates for the three species were variable across different sampling periods. The estimated number of individuals in the sampled area varied per sampling episode from 136 (s.e. 62) to 222 (s.e. 48) for snubfin, from 48 (s.e. 7) to 207 (s.e. 14) for humpbacks and from 34 (s.e. 6) to 75 (s.e. 9) for bottlenose dolphins. Apparent survival was estimated for snubfin at 0.81 (s.e. 0.11), humpbacks at 0.59 (s.e. 0.12) and bottlenose at 0.51 (s.e. 0.17) per annum. Key conclusions (1) The values derived here provide some of the only estimates of local population size for these species across monsoonal northern Australia; (2) population-size estimates varied considerably among seasons or sampling episodes; (3) the low apparent survival probabilities indicated that many individuals may move at scales larger than the study area; (4) density of snubfin and humpback dolphins in the present study area exceeded the few other estimates available for these species elsewhere in Australia. Implications The present study provided the first baseline estimates of abundance and apparent survival for three coastal dolphin species in monsoonal northern Australia. Such information is becoming increasingly important as development pressures intensify in coastal areas. Sampling protocols for future monitoring and impact assessment need an enhanced consideration of seasonality and scale issues.

Mapping Pedestrian Journey Times using a Network-based GIS Model

Please click here to download the map associated with this article. Pedestrian accessibility maps often display a Euclidean distance (straight line between two points) buffer around a destination. This paper presents a map that demonstrates how a pedestrian network can be used to improve the accuracy of these results and model the effect of gradient and demographics on walk speed. A bespoke GIS model was developed to undertake the assessment, which is explained along with the key assumptions made. The model was used to assess pedestrian access levels from five proposed development sites in the West Northamptonshire area to the key local facilities. The results quantified access using defined threshold journey times to provide the percentage of dwellings within this limit. This helped West Northamptonshire Development Corporation to consider the specific pedestrian access issues that each site may have, which forms part of their process of delivering sustainable development. The model developed could be applied to other geographical regions and scenarios. More generally, the study showed that GIS is a key tool for improving the evidence base as part of the spatial planning process.

Translocation of black‐headed dwarf chameleons Bradypodion melanocephalum in Durban, KwaZulu‐Natal, South Africa

The coastal population of the black‐headed dwarf chameleon Bradypodion melanocephalum is threatened by rapid urban expansion in and around Durban which lies in the centre of the chameleon population's distribution. Translocations of threatened species from urban development sites is a mitigation method that is used in various parts of the world. The translocation of B. melanocephalum largely by volunteers from a proposed light industrial business park to two neighbouring areas with partially restored habitats was eventually successful in one recipient area and unsuccessful in the other. The results suggest that translocations of B. melanocephalum from development construction sites to recipient areas will only be successful if adequate time and resources are available for: a) finding and securing suitable areas for habitat restoration; b) sufficient restoration of the indigenous vegetation in the recipient areas before the capture and translocation of B. melanocephalum from the proposed development sites; c) searching for, and capture of, all B. melanocephalum on the development sites, and; d) long‐term management of the restored habitat in a manner that does not result in significantly elevated mortality or dispersal of B. melanocephalum. Monitoring of B. melanocephalum numbers in the recipient sites, by at least two people per transect, is important to gauge the success or otherwise of the translocation. Monitoring can give insights into the controllable factors that have an impact on the numbers of chameleons, and provide suggestions as how to improve the management of the habitat.

2D Seismic Refraction Tomography Survey on Metasediment at a Proposed Development Site in Dengkil, Selangor

A geophysical survey using seismic refraction technique was carried out at a proposed development site at MINT­ Oengkil. The aim of the study was to characterize the subsurface materials based on seismic P-S wave velocities as well as to correlate those data with the lithologic logs and the standard penetration test (SPT) N-values. The study area is about 40 km squares, consisting of shale, slate and siltstones of the Kenny Hill Formation. Seismic surveys were carried out using ABEM MK 3 as a recording seismograph, and 24 units of 14Hz-frequency geophones 'to record the incoming seismic waves. The data were processed using an OPTIM software to produce sections of 20 velocity model profiles. Results show P-wave velocity of clayey silt (SPT=3-11) is ranging from 300-500mls and S-wave velocity is ranging from 80-100mls. P-wave velocity value for sandy silt (N=12-16) is ranging from 500-800mls and S-wave velocity is found ranging from 100-300mls. P-wave velocity value representing hard silt with gravel (N=20-50) is ranging from 900-1600mls and S-wave velocity is ranging from 300- 450mls. The S-wave velocity obtained from seismic surveys show only slight difference in values compared with those calculated using SPT N values. The calculated Poisson ratio value ranging from 0.43-0.47, representing clayey-silt and sandy­ silt. Velocity model sections were correlated well with the lithologic and SPT N values at each borehole. In the study area, the SPT test was terminated when the N value reached 50 which corresponds to the hard gravelly silt soil. The SPT test was only conducted in soft soil zone without penetrating the bedrock, whereas for the seismic survey, some of the 20 velocity model cross sections show P-wave velocity values range from 3500 to 4000mls at a depth of more than 15m. This high velocity values can be interpreted as representing slightly weathered to fresh rock.

Indigenous and spontaneous vegetation: their relationship to urban development in the city of Leeds, UK

The concepts of indigenous and spontaneous vegetation are considered as subsets of the broader category, semi-natural vegetation. Indigenous vegetation is conceptualised as that which has originated in a rural landscape and developed over a time period of several centuries or more, either naturally or as a result of traditional management methods, together with the environmental conditions supporting it. In contrast, spontaneous vegetation is that which has naturally colonised derelict urban sites, mainly within the last century. An investigation, using map and aerial photographic data, examined the relative proportions of potentially indigenous and spontaneous vegetation on proposed development sites in Leeds, a large industrial city in the UK. Results suggested that spontaneous vegetation occupied approximately 13% by area of the development sites while possible indigenous vegetation occupied as little as 5%. However, further analysis suggested that approximately 25% of the proposed development sites were within 0.5 km of a designated site containing indigenous vegetation. It is argued that both types of semi-natural vegetation can make positive contributions to the urban environment but that public perception of spontaneous vegetation and, in particular, the locations where it occurs, are often negative. Further research into public perceptions of semi-natural vegetation and ways of incorporating it into urban development are required.

Coastal Vegetation of Taunovo Bay, Pacific Harbour, Viti Levu, Fiji - A Proposed Development Site

Using four 100 � 10 m transects, the coastal vegetation types and their horizontal stratification at Taunovo Bay, Pacific Harbour, were investigated. The common stratification pattern of herb zone, shrub zone (dominated by the invasive species Chrysobalanus icaco) and tree zone was observed. Littoral forest composed of species commonly associated with sandy beaches and species commonly associated lowland rainforest was observed. This vegetation type is here reported for the first time from Fiji and is probably caused by siliceous deposits from a nearby river. A detailed study of the extend, composition and distribution of this unique vegetation type should be conducted before the development project (planned at the study site) is approved.