scholarly journals Status of the relict population of the Critically Endangered Madagascar spider tortoise Pyxis arachnoides

Oryx ◽  
2012 ◽  
Vol 46 (3) ◽  
pp. 457-463 ◽  
Author(s):  
Ryan C. J. Walker ◽  
Tsilavo H. Rafeliarisoa
Keyword(s):  
Protected Areas ◽  
Distance Sampling ◽  
Habitat Destruction ◽  
Species Range ◽  
Line Transect ◽  
Anthropogenic Pressures ◽  
Community Based Conservation ◽  
Relict Population ◽  
Distance Model ◽  
C 71

AbstractThe Madagascar spider tortoise Pyxis arachnoides is endemic to the coastal dry forests of south-west Madagascar. In recent years its range has been reduced by c. 71%, with the species now confined to eight fragmented populations occupying a total of 2,464 km2. These remaining populations are facing a significant threat of extinction because of habitat destruction and other anthropogenic pressures. We developed methodology for a line transect distance sampling survey and applied it systematically across the species' range. The resulting distance model estimated a mean density of 226.9 tortoises km−2 (95% confidence interval, CI, 168.1–306.3) and a total population of 664,980 (95% CI 492,680–897,550). Fragmentation of the species’ range suggests the current population could be <30% of the historical population. Of the remaining population 73.5% falls within protected areas. However, nine of these 12 protected areas are designated as IUCN category III, V or VI parks, allowing some extractive activities to be undertaken. The most effective strategy for the conservation of P. arachnoides would be to reduce the threats to this species and its habitat, and to develop and expand the current community-based conservation and poverty alleviation programmes in the region.

scholarly journals Distance sampling reveals Cambodia's Eastern Plains Landscape supports the largest global population of the Endangered banteng Bos javanicus

Oryx ◽  
2012 ◽  
Vol 46 (4) ◽  
pp. 563-566 ◽  
Author(s):  
Thomas N. E. Gray ◽  
Sovanna Prum ◽  
Chanrattana Pin ◽  
Channa Phan
Keyword(s):  
Protected Areas ◽  
Land Use Planning ◽  
Distance Sampling ◽  
Line Transect ◽  
Robust Estimate ◽  
Bos Javanicus ◽  
Transect Sampling ◽  
Line Transects ◽  
Dry Seasons ◽  
Global Population

AbstractThe banteng Bos javanicus is a globally threatened species of wild cattle restricted to South-East Asia. We report the first robust estimate of banteng density and population size from anywhere in the species' global range, using distance-based line transect sampling within two protected areas, Mondulkiri Protected Forest and Phnom Prich Wildlife Sanctuary, which form part of the Eastern Plains Landscape, Cambodia. We surveyed 110 line transects multiple times during the dry seasons of 2009–2010 and 2010–2011. In a total survey effort of 1,310 km there were 63 encounters with banteng. The mean estimate of the population across the 3,406 km2 study area is 3,200 (95% confidence interval 1,980–5,170). This suggests that the protected area complex of the Eastern Plains Landscape supports the majority of the global population of banteng. Stronger protection, both in the form of increased anti-hunting and poaching patrols and integrated land-use planning to prevent habitat loss within protected areas, is essential for securing wild cattle populations in the Eastern Plains Landscape.

scholarly journals Getting the Most From Surveys: How Method Selection and Method Modification Impact Butterfly Survey Data

2021 ◽  
Author(s):  
Katherine C Kral-O’Brien ◽  
Adrienne K Antonsen ◽  
Torre J Hovick ◽  
Ryan F Limb ◽  
Jason P Harmon
Keyword(s):  
Species Richness ◽  
New Species ◽  
Count Data ◽  
Distance Sampling ◽  
Line Transect ◽  
Similar Species ◽  
Method Selection ◽  
M 10 ◽  
Sampling Procedures

Abstract Many methods are used to survey butterfly populations, with line transect and area surveys being prominent. Observers are typically limited to search within 5 or 10 m from the line, while observers are unrestricted in larger specified search regions in area surveys. Although methods differ slightly, the selection is often based on producing defendable data for conservation, maximizing data quality, and minimizing effort. To guide method selection, we compared butterfly surveys using 1) line versus area methods and 2) varying width transects (5 m, 10 m, or unrestricted) using count data from surveys in North Dakota from 2015 to 2018. Between line and area surveys, we detected more individuals with area surveys, even when accounting for effort. However, both methods accumulated new species at similar rates. When comparing transect methodology, we detected nearly 60% more individuals and nine more species when transect width increased from 5 m to unrestricted, despite similar effort across methodology. Overall, we found line surveys slightly less efficient at detecting individuals, but they collected similar species richness to area surveys when accounting for effort. Additionally, line surveys allow the use of unrestricted-width transects with distance sampling procedures, which were more effective at detecting species and individuals while providing a means to correct count data over the same transect length. Methods that reduce effort and accurately depict communities are especially important for conservation when long-term datasets are unavailable.

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.

The importance of survey design in distance sampling: field evaluation using domestic sheep

2011 ◽  
Vol 38 (3) ◽  
pp. 221 ◽  
Author(s):  
Tom A. Porteus ◽  
Suzanne M. Richardson ◽  
Jonathan C. Reynolds
Keyword(s):  
Population Size ◽  
Survey Design ◽  
Distance Sampling ◽  
Field Evaluation ◽  
Stage I ◽  
Stage Ii ◽  
Line Transect ◽  
Domestic Sheep ◽  
Management Decisions ◽  
Mobile Species

Context Sampling methods to estimate animal density require good survey design to ensure assumptions are met and sampling is representative of the survey area. Management decisions are often made based on these estimates. However, without knowledge of true population size it is not possible for wildlife biologists to evaluate how biased the estimates can be if survey design is compromised. Aims Our aims were to use distance sampling to estimate population size for domestic sheep free-ranging within large enclosed areas of hill country and, by comparing estimates against actual numbers, examine how bias and precision are impaired when survey design is compromised. Methods We used both line and point transect sampling to derive estimates of density for sheep on four farms in upland England. In Stage I we used limited effort and different transect types to compromise survey design. In Stage II we increased effort in an attempt to improve on the Stage I estimates. We also examined the influence of a walking observer on sheep behaviour to assess compliance with distance sampling assumptions and to improve the fit of models to the data. Key results Our results show that distance sampling can lead to biased and imprecise density estimates if survey design is poor, particularly when sampling high density and mobile species that respond to observer presence. In Stage I, walked line transects were least biased; point transects were most biased. Increased effort in Stage II reduced the bias in walked line transect estimates. For all estimates, the actual density was within the derived 95% confidence intervals, but some of these spanned a range of over 100 sheep per km2. Conclusions Using a population of known size, we showed that survey design is vitally important in achieving unbiased and precise density estimation using distance sampling. Adequate transect replication reduced the bias considerably within a compromised survey design. Implications Management decisions based on poorly designed surveys must be made with an appropriate understanding of estimate uncertainty. Failure to do this may lead to ineffective management.

scholarly journals Description of two new species of Avicularia Lamarck 1818 and redescription of Avicularia diversipes (C. L. Koch 1842) (Araneae, Theraphosidae, Aviculariinae)—three possibly threatened Brazilian species

Zootaxa ◽  
2009 ◽  
Vol 2223 (1) ◽  
pp. 25-47 ◽  
Author(s):  
ROGÉRIO BERTANI ◽  
CAROLINE SAYURI FUKUSHIMA
Keyword(s):  
New Species ◽  
Protected Areas ◽  
Conservation Status ◽  
Original Description ◽  
Color Pattern ◽  
Habitat Destruction ◽  
Southern State ◽  
Two New Species ◽  
Specimen Identification ◽  
Brazilian Atlantic Rainforest

Avicularia diversipes (C. L. Koch 1842) known previously only from its original description is redescribed along with Avicularia sooretama sp. nov. and Avicularia gamba sp. nov. The three species are endemic to Brazilian Atlantic rainforest. With other Avicularia species, they share a procurved anterior eye row, slender embolus and medially folded spermathecae, whereas they have unusual characters, such as a very long and spiraled embolus (A. diversipes) and spermathecae with multilobular apex (A. sooretama sp. nov.). Furthermore, the three species lack a tibial apophysis in males and share a distinctive color pattern ontogeny that is not known in any other Avicularia species. The conservation status of the three species is discussed, especially with respect to endemism, illegal trafficking and habitat destruction. The creation of protected areas in southern State of Bahia, Brazil, is recommended, as well as the inclusion of these species in IUCN and CITES lists. Appendices with figures and species information are presented to facilitate correct specimen identification by custom officers, in order to limit illegal traffic.

scholarly journals The influence of animal mobility on the assumption of uniform distances in aerial line-transect surveys

2008 ◽  
Vol 35 (4) ◽  
pp. 275 ◽  
Author(s):  
Rachel M. Fewster ◽  
Colin Southwell ◽  
David L. Borchers ◽  
Stephen T. Buckland ◽  
Anthony R. Pople
Keyword(s):  
Survey Design ◽  
Distance Sampling ◽  
High Mobility ◽  
Line Transect ◽  
Transect Line ◽  
Aerial Surveys ◽  
Pack Ice ◽  
Capture Recapture ◽  
Distance Data ◽  
Crabeater Seals

Line-transect distance sampling is a widely used method for estimating animal density from aerial surveys. Analysis of line-transect distance data usually relies on a requirement that the statistical distribution of distances of animal groups from the transect line is uniform. We show that this requirement is satisfied by the survey design if all other assumptions of distance sampling hold, but it can be violated by consistent survey problems such as responsive movement of the animals towards or away from the observer. We hypothesise that problems with the uniform requirement are unlikely to be encountered for immobile taxa, but might become substantial for species of high mobility. We test evidence for non-uniformity using double-observer distance data from two aerial surveys of five species with a spectrum of mobility capabilities and tendencies. No clear evidence against uniformity was found for crabeater seals or emperor penguins on the pack-ice in East Antarctica, while minor non-uniformity consistent with responsive movement up to 30 m was found for Adelie penguins. Strong evidence of either non-uniformity or a failure of the capture–recapture validating method was found for eastern grey kangaroos and red kangaroos in Queensland.

scholarly journals Assessment of the main factors impacting community members’ attitudes towards tourism and protected areas in six southern African countries

Koedoe ◽  
2014 ◽  
Vol 56 (2) ◽  
Author(s):  
Susan Snyman
Keyword(s):  
Protected Areas ◽  
Southern Africa ◽  
Formal Education ◽  
Benefit Sharing ◽  
Community Members ◽  
Conservation Areas ◽  
African Countries ◽  
Conservation Implications ◽  
Community Based Conservation ◽  
Future Success

In southern Africa, many early conservation efforts from the late 1800s and early 1900s either displaced local communities or restricted their access to natural resources. This naturally affected community attitudes towards protected areas and efforts were later made to rectify growing tensions. In the last few decades of the 20th century, these efforts led to conservation and ecotourism models that increasingly included communities in the decision-making and benefit-sharing process in order to garner their support. Although the results of these policies were mixed, it is clear that the future success of conservation and, consequently, ecotourism in many areas will depend on the attitudes and behaviour of communities living in or adjacent to protected areas. Managing and understanding community expectations and attitudes under varying socio-economic circumstances will lead to more efficient, equitable and sustainable community-based conservation and ecotourism models. This study was based on 1400 community interview schedules conducted in Botswana, Malawi, Namibia, South Africa, Zambia and Zimbabwe, allowing for an accurate comparison of attitudes across countries, protected areas and communities. The results highlighted important demographic and socio-economic factors to consider in terms of understanding the attitudes of those living in and around protected areas. Suggestions were put forward for managing community relationships and garnering long-term support for protected areas and ecotourism. Conservation implications: It was observed that, in general, community members living in or adjacent to conservation areas in southern Africa have an understanding and appreciation of the importance of conservation. Formal education was found to positively impact attitudes and human–wildlife conflict negatively impacted attitudes, highlighting important policy focus areas.

scholarly journals Registro de la Serpiente Coral de Steindachneri Micrurus steindachneri (Squamata: Elapidae) en el Área Ecológica de Conservación Municipal Tinajillas-Río Gualaceño

2016 ◽  
Vol 8 (14) ◽  
Author(s):  
Veronica Lorena Urgiles ◽  
Juan Carlos Sánchez ◽  
Pedro Xavier Astudillo
Keyword(s):  
Protected Areas ◽  
Protected Area ◽  
Habitat Destruction ◽  
Coral Snake

Registramos a la Serpiente Coral de Steindachner Micrurus steindachneri en el Área Ecológica de Conservación Municipal Tinajillas-Río Gualaceño, provincia de Morona Santiago, Ecuador. La especie ha sido previamente registrada en solo dos áreas protegidas nacionales en Ecuador. Este reporte es el primero en una zona protegida local y resalta la importancia de los sistemas naturales de protección municipal para la conservación de especies sensibles a la destrucción de su hábitat.  Record of Steindachner Coral Snake Micrurus steindachneri (Squamata: Elapidae) in the Municipal Conservation Ecological Area Tinajillas-Río GualaceñoWe registered the Steindachner Coral Snake Micrurus steindachneri in the Municipal Conservation Ecological Area Tinajillas-Río Gualaceño, province of Morona Santiago, Ecuador. The species has been previously recorded in just two national protected areas in Ecuador. This report is the first in a local protected area, and highlights the importance of municipal protection for conservation of species that are vulnerable to habitat destruction.

scholarly journals Estimating abundance of the Endangered onager Equus hemionus onager in Qatruiyeh National Park, Iran

Oryx ◽  
2013 ◽  
Vol 47 (2) ◽  
pp. 266-272 ◽  
Author(s):  
Mahmoud-Reza Hemami ◽  
Moslem Momeni
Keyword(s):  
Growth Rate ◽  
Protected Area ◽  
National Park ◽  
Natural Populations ◽  
Distance Sampling ◽  
Line Transect ◽  
Management Interventions ◽  
Equus Hemionus ◽  
Wild Ass ◽  
Semi Arid

AbstractHistorically, the onager or Persian wild ass Equus hemionus onager, endemic to Iran, was widespread on the arid and semi-arid central steppes but only two natural populations remain. We estimated the population density of the onager in Qatruiyeh National Park using line transect distance sampling. Transects were surveyed on three plains in the Park and the results compared with total counts conducted by the Department of Environment. Our estimate (109 onagers per 100 km2; 95% confidence interval 67–179) is similar to that obtained by the total counts (137 onagers per 100 km2). Distance sampling is therefore a promising method for estimating the abundance of the onager. Using the annual censuses performed by the Department of Environment over the last 13 years we estimated that the population has a growth rate of 0.09. During the same period the onager population in the Touran Protected Complex has experienced a severe decline. The high density of onagers within the National Park indicates the unsuitability of adjacent habitats, including Bahram-e-Goor Protected Area, for this species. Lack of sufficient security and poorly distributed water sources appear to be the main reasons discouraging onagers from entering the Bahram-e-Goor Protected Area. We recommend and describe management interventions that could potentially assist in maintaining the last surviving onager populations in Iran.

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