Adaptive line transect survey for harbor porpoises

2021 ◽  
pp. 3-11
Author(s):  
D. Palka ◽  
J. Pollard
Keyword(s):  
Line Transect ◽  
Line Transect Survey ◽  
Harbor Porpoises

PROFIL KERAGAMAN VEGETASI EKOSISTEM MANGROVE DI DESA TAMUKU KABUPATEN LUWU UTARA

2019 ◽  
Vol 5 ◽  
pp. 104
Author(s):  
Suhendra Purnawan ◽  
Subari Yanto ◽  
Ernawati S.Kaseng
Keyword(s):  
Survey Methods ◽  
Mangrove Ecosystem ◽  
Line Transect ◽  
Mangrove Forests ◽  
Vegetation Diversity ◽  
Line Transect Survey ◽  
Analysis Technique ◽  
Mangrove Vegetation ◽  
Data Collection Technique ◽  
The Impact

This study aims to describe the profile of vegetation diversity in the mangrove ecosystem in Tamuku Village, Bone-Bone-Bone District, North Luwu Regency. This research is a qualitative research using survey methods. The data collection technique uses the Quadrant Line Transect Survey technique. The data analysis technique uses the thinking flow which is divided into three stages, namely describing phenomena, classifying them, and seeing how the concepts that emerge are related to each other. The results of this study are the profile of mangrove vegetation in Tamuku Village, which is still found 16 varieties of true mangrove vegetation and 7 varieties of mangrove vegetation joined in the coastal area of Tamuku Village, Bone-Bone District, North Luwu Regency, South Sulawesi. The condition of mangrove vegetation in Tamuku Village is currently very worrying due to human activities that cause damage such as the project of normalization of flow, opening of new farms, disposal of garbage, water pollution due to chemicals, and exploitation of mangrove forests for living needs. The impact is ecosystem damage and reduced vegetation area as a place to grow and develop mangroves.

Harbor porpoise (Phocoena phocoena) recovery in the inland waters of Washington: estimates of density and abundance from aerial surveys, 2013–2015

2016 ◽  
Vol 94 (7) ◽  
pp. 505-515 ◽  
Author(s):  
Thomas A. Jefferson ◽  
Mari A. Smultea ◽  
Sarah S. Courbis ◽  
Gregory S. Campbell
Keyword(s):  
Puget Sound ◽  
Distance Sampling ◽  
Line Transect ◽  
Inland Waters ◽  
San Juan ◽  
Phocoena Phocoena ◽  
Harbor Porpoise ◽  
San Juan Islands ◽  
Juan De Fuca ◽  
Harbor Porpoises

The harbor porpoise (Phocoena phocoena (L., 1758)) used to be common in Puget Sound, Washington, but virtually disappeared from these waters by the 1970s. We conducted systematic aerial line-transect surveys (17 237 km total effort) for harbor porpoises, with the goal of estimating density and abundance in the inland waters of Washington State. Surveys in Puget Sound occurred throughout the year from 2013 to 2015, and in the Strait of Juan de Fuca and the San Juan Islands (and some adjacent Canadian waters) in April 2015. We used a high-wing, twin-engine Partenavia airplane and four observers (one on each side of the plane, one looking through a belly port, and one recording data). A total of 1063 harbor porpoise groups were sighted. Density and abundance were estimated using conventional distance sampling methods. Analyses were limited to 447 harbor porpoise groups observed during 5708 km of effort during good sighting conditions suitable for line-transect analysis. Harbor porpoises occurred in all regions of the study area, with highest densities around the San Juan Islands and in northern Puget Sound. Overall, estimated abundance for the Washington Inland Waters stock was 11 233 porpoises (CV = 37%, 95% CI = 9 616 – 13 120). This project clearly demonstrated that harbor porpoises have reoccupied waters of Puget Sound and are present there in all seasons. However, the specific reasons for their initial decline and subsequent recovery remain uncertain.

scholarly journals The Last-Surviving Moroccan Dorcas Gazelle (Gazella dorcas massaesyla) Viability Analysis [M’Sabih Talaa Reserve, Morocco]

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Ait Baamrane Moulay Abdeljalil ◽  
Znari Mohammed ◽  
El Mercht Said ◽  
Bellout Siham ◽  
Naimi Mohamed
Keyword(s):  
Population Viability Analysis ◽  
Environmental Stochasticity ◽  
General Interest ◽  
Line Transect ◽  
Catastrophic Events ◽  
Viability Analysis ◽  
Line Transect Survey ◽  
Management Measures ◽  
Feral Dogs ◽  
Considerable Impact

The single remnant Moroccan dorcas gazelle (Gazella dorcas massaesyla) has been isolated for more than five decades in the M’Sabih Talaa reserve, an arid area of west-central Morocco. This population has been subject to different disturbances, especially poaching and depredation by feral dogs. A five-season line transect survey revealed that the population size has been halved in less than 15 years with a lower apparent fecundity rate. In the present work, we carried out a population viability analysis simulating different scenarios using VORTEX software based on available demographic and life-history data from captive populations,. A sensitivity analysis revealed that inbreeding depression and possible catastrophic events could have a considerable impact on the population’s prospects. Scenarios of splitting population into two subpopulations with different management measures reducing/deleting mortality sources, is proposed. Such scenarios resulted in reducing the consequences of catastrophic events would significantly mitigate the harmful effects of both inbreeding and environmental stochasticity. These results may be of a general interest to conservationists dealing with this unique and imperiled population.

Evaluation of analystical procedures for density estimation from line-transect data: data grouping, data truncation and the unit of analysis

1993 ◽  
Vol 20 (4) ◽  
pp. 433 ◽  
Author(s):  
C Southwell ◽  
K Weaver
Keyword(s):  
Cluster Analysis ◽  
Survey Data ◽  
Density Estimation ◽  
Line Transect ◽  
Density Estimates ◽  
Unit Of Analysis ◽  
Line Transect Survey ◽  
Data Truncation ◽  
Data Grouping ◽  
Non Parametric

We examined three aspects of line-transect analytical procedures: data grouping, data truncation and the use of individuals or clusters as the analytical unit. Bias and precision of density estimation in relation to various levels of these factors were assessed for 4 types of line-transect estimator (simple parametric, generalised parametric, non-parametric and quasi-strip) using line-transect survey data from macropod populations of known density. The effect of data grouping on bias and precision varied between estimators. Bias was stable across all grouping levels tested for the simple parametric estimator, and stable across aU but the coarsest grouping level for the generalised parametric and non-parametric estimators, but varied substantially across the range of levels tested for the quasi-strip estimator. Precision improved as the number of grouping levels increased for all estimators tested, but the extent of improvement varied between estimators, and for the estimator most affected, improvement was marginal beyond intermediate grouping levels. Density estimates were generally more accurate and precise when analysed in ungrouped form than in grouped form. No effects of truncation on bias or precision were detected. Varying the analytical unit did not affect bias, but precision was significantly lower for cluster analysis than individual analysis for all estimators.

scholarly journals Aerial line transect survey to estimate abundance of marsh deer (Blastocerus dichotomus) (Illiger, 1815)

2005 ◽  
Vol 48 (5) ◽  
pp. 807-814 ◽  
Author(s):  
Artur Andriolo ◽  
Ubiratan Piovezan ◽  
Mateus José Rodrigues Paranhos da Costa ◽  
Jeff Laake ◽  
José Maurício Barbanti Duarte
Keyword(s):  
Population Size ◽  
River Basin ◽  
Distance Sampling ◽  
Aerial Survey ◽  
Line Transect ◽  
Sampling Methodology ◽  
Future Analysis ◽  
Line Transect Survey ◽  
Blastocerus Dichotomus ◽  
The Impact

The objective was to estimate abundance of marsh deer in the Paraná River basin of this work. The results provided information to support further analysis of the impact of the Porto Primavera flooding lake over population. Sixty-nine animals were recorded by aerial survey using distance sampling methodology. Animals were widely distributed throughout the study area. The uncorrected data resulted in a estimate density of 0.0035 ind/ha and a population size of 636 individuals. Correcting the g for the animals that could be missed the calculated abundance was 896 (CV=0.27) individuals. This methodology was applied with success to survey marsh deer. The result was important to evaluate the marsh deer status in the area, and for future analysis of the impact of the flooding dam.

The April 2009 Gulf of Alaska Line-Transect Survey (Goals) in the Navy Training Exercise Area

2009 ◽  
Author(s):  
Brenda K. Rone ◽  
Annie B. Douglas ◽  
Phil Clapham ◽  
Anthony Martinez ◽  
Laura J. Morse ◽  
...  
Keyword(s):  
Gulf Of Alaska ◽  
Line Transect ◽  
Training Exercise ◽  
Line Transect Survey

scholarly journals Estimation of Kapapa Bajing Population (Callosciurus notatus Boddaert, 1785) Family Sciuridae in Nagari Koto Dalam, Padang Sago, Sumatera Barat

2018 ◽  
Vol 5 (2) ◽  
pp. 210
Author(s):  
Lusi Andalisa ◽  
Rizaldi Rizaldi ◽  
Jabang Nurdin
Keyword(s):  
Population Density ◽  
Survey Method ◽  
Line Transect ◽  
Line Transect Survey ◽  
West Sumatra ◽  
Estimate Population Density

Estimation of the plantain squirrel (Callosciurus notatus Boddaert, 1785) population was conducted from Februari to May 2016. This study aimed to estimate population density in the traditional coconut plantation, Nagari Koto Dalam, Padang Pariaman. The population density was estimated using line transect survey method. Population density of the squirrels in Nagari Koto Dalam was 5.5 ind/ha. This study shows that population density of the squirrel comparable to previous studies in West Sumatra.

scholarly journals The Use of Global Positioning Systems to Record Distances in a Helicopter Line-Transect Survey

2006 ◽  
Vol 34 (3) ◽  
pp. 759-763 ◽  
Author(s):  
TIAGO A. MARQUES ◽  
MAGNUS ANDERSEN ◽  
SIGNE CHRISTENSEN-DALSGAARD ◽  
STANISLAV BELIKOV ◽  
ANDREI BOLTUNOV ◽  
...  
Keyword(s):  
Line Transect ◽  
Global Positioning Systems ◽  
Positioning Systems ◽  
Line Transect Survey ◽  
Global Positioning
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