Influence of Observers and Stream Flow on Northern Two-lined Salamander (Eurycea Bislineata Bislineata) Relative Abundance Estimates in Acadia and Shenandoah National Parks, USA

Abstract. Sukmasuang R, Charaspet K, Panganta T, Pla-ard M, Khioesree N, Thongbanthum J. 2020. Diversity, abundance, activity period, and factors affecting the appearance of wildlife around the corridors between Khao Yai-Thap Lan National Parks, Thailand by camera trapping. Biodiversitas 21: xxxx. The study on diversity, abundance, activity period, and factors affecting the appearance of wildlife around the wildlife corridors was investigated using camera trap method from September 2017 to November 2018. The corridors located at the royal highway in Ban Bu Phram Subdistrict, Na Di District, Prachinburi Province, Thailand. Based on 21 camera locations, 3,172 trap nights and 6,707 captured pictures totally resulted that a total of 37 species represented by 14 orders and 26 families consisting of 13 species of herbivores, 10 species of carnivores, 10 species of aves and 4 species of reptiles were photographically recorded in the area. Among the wildlife species, 4 species were listed as endangered according to IUCN Red List including Malayan pangolin, large-spotted civet, dhole, Asian forest tortoise, 5 species were listed as vulnerable, there were Sumatran serow, gaur, sambar deer, northern pig-tailed macaque, Asian black bear, and 21 species were listed as least concerned, such as lesser oriental chevrotain, Himalayan porcupine, Asian palm civet, large Indian civet, small Indian civet, hog badger, small Asian mongoose, golden jackal, red jungle fowl, Siamese fireback, coral-billed ground cuckoo and so on. Based on photographic rate of each species, the herbivorous wildlife species represented the relative abundance index of 15.04. The carnivorous wildlife species which had the relative abundance index of 4.70, while the RAI of the aves and reptiles were 1.91 and 0.12. The activity period found that the majority were found at night. This study showed that wildlife corridors have a high influence on the appearance of wildlife, demonstrating the potential of the corridors be used by wildlife for travelling. However, the wildlife corridors should be designed to be suitable for the particular types of animals, especially by increasing the construction of underpasses for mammal at locations with the highest and the number of crossings and also must reduce noise from vehicles, especially at night.

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Oligarchic dominance in western Amazonian plant communities

Journal of Tropical Ecology ◽

10.1017/s0266467405002579 ◽

2005 ◽

Vol 21 (6) ◽

pp. 613-626 ◽

Cited By ~ 58

Author(s):

Manuel J. Macía ◽

Jens-Christian Svenning

Keyword(s):

National Parks ◽

Plant Communities ◽

Relative Abundance ◽

Woody Plants ◽

Spatial Scales ◽

Common Species ◽

Taxonomic Rank ◽

The Family ◽

Family Level ◽

Amazonian Forests

The oligarchy hypothesis proposes that large areas of Amazonian plant communities are dominated by limited sets of species. We tested this hypothesis by (1) quantifying dominance of the 10 most common species, genera and families in each region; and (2) assessing the consistency of relative abundance ranks between areas and across scales in dominance patterns for trees and lianas in two distant Amazonian regions (∼1900 km), the Yasuní and Madidi National Parks in Ecuador and Bolivia, respectively. The analyses were based on sixty-nine 0.1-ha plots in which all woody plants with a diameter at breast height (dbh) ≥2.5 cm were inventoried (19 775 individuals and 1729 species in total). The plots were located at two Yasuní and five Madidi sites, with an average of 10 plots per site. Overall, oligarchic dominance was pronounced at all the spatial scales investigated, although decreasing with increasing scale. Cross-scale relative abundance ranks were more consistent in Yasuní than in Madidi, while no such difference was apparent within single sites. Quantitative dominance and consistency of relative abundance ranks increased with taxonomic rank, being stronger at the family level than at genus and species levels. Species-level dominance was somewhat stronger within the 10 most common families in either region, than in other families. Dominance was similarly strong for canopy (dbh ≥10 cm) and understorey trees (dbh <10 cm), and less pronounced among lianas. In conclusion, our results provide strong evidence that western Amazonian forests can be dominated by limited oligarchies of species, genera and families over large expanses.

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Distribution, abundance and conservation status of Grauer's gorilla

Oryx ◽

10.1046/j.1365-3008.1998.d01-22.x ◽

1998 ◽

Vol 32 (2) ◽

pp. 122-130 ◽

Cited By ~ 9

Author(s):

Jefferson S. Hall ◽

Kristin Saltonstall ◽

Bila-Lsia Inogwabini ◽

Ilambu Omari

Keyword(s):

National Parks ◽

Human Population ◽

Population Growth Rate ◽

Total Population ◽

Democratic Republic ◽

Democratic Republic Of Congo ◽

Conservation Status ◽

Eastern Region ◽

Wildlife Use ◽

Abundance Estimates

This report updates the distribution and provides abundance estimates for Grauer's gorilla Gorilla gorilla graueri across its 90,000-sq-km range. The authors divide the range of Grauer's gorilla into four regions within which they identify 11 populations and estimate a total of c. 16,900 individuals. Gorillas found in the Kahuzi-Biega lowland-Kasese region represent 86 per cent of the subspecies's total population. Further, approximately 67 per cent of known Grauer's gorillas inhabit Kahuzi-Biega, Maiko and Virunga National Parks. The eastern region of the Democratic Republic of Congo (formerly Zaire) has an extremely high human population growth rate indicating that deforestation and wildlife use trends will continue to increase. Thus, in spite of the encouraging results of surveys to identify populations and characterize abundance, no Grauer's gorilla population should be considered safe from extirpation.

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Calculation of untrawlable areas within the boundaries of a bottom trawl survey

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f03-055 ◽

2003 ◽

Vol 60 (6) ◽

pp. 657-669 ◽

Cited By ~ 20

Author(s):

Mark Zimmermann

Keyword(s):

Relative Abundance ◽

Species Group ◽

Bottom Trawl ◽

Trawl Survey ◽

Gis Analysis ◽

Target Species ◽

Abundance Estimates ◽

Original Target ◽

Catch Rates ◽

Trawl Surveys

A geographic information system (GIS) analysis of 5039 bottom trawl events from U.S. west coast bottom trawl surveys (19771998) estimated that the survey area was about 77% trawlable but five of the 30 strata were less than 50% trawlable. Untrawlable areas, by definition, cannot be surveyed with the bottom trawl; however, there has never been a means of identifying and excluding these areas from relative abundance estimates, which are calculated only from hauls completed in the trawlable portions of each stratum. Unknown amounts of untrawlable habitat are a problem for relative abundance estimation in many bottom trawl surveys. This manuscript describes one method of using the bottom trawling events of a survey, such as ripped-up hauls and abandoned stations, to calculate the amount of area that is untrawlable. A comparison of catch rates between undamaged tows and a limited number of damaged tows, which are normally discarded as faulty samples, showed that Sebastes catch rates were generally higher in damaged tows. Thus untrawlable areas may have substantial importance on relative abundance estimates of Sebastes, the original target species group for this survey.

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Distribution and Abundance of Cetaceans in Icelandic Waters over 30 Years of Aerial Surveys

NAMMCO Scientific Publications ◽

10.7557/3.4805 ◽

2020 ◽

Vol 11 ◽

Author(s):

Daniel Pike ◽

Thorvaldur Gunnlaugsson ◽

Johann Sigurjonsson ◽

Gisli Vikingsson

Keyword(s):

Relative Abundance ◽

Humpback Whales ◽

Line Transect ◽

Balaenoptera Acutorostrata ◽

Aerial Surveys ◽

Minke Whales ◽

Abundance Estimates ◽

Ecosystem Changes ◽

Common Minke Whale ◽

Icelandic Waters

Beginning in 1986, 7 aerial surveys covering the coastal waters of Iceland have been conducted up to 2016. In addition, several partial surveys covering portions of the same area and at different times of the year have been flown in the same 30 year time span. We present previously unpublished abundance estimates, corrected to the extent feasible for known biases, for common minke whales (Balaenoptera acutorostrata), humpback whales (Megaptera novaeangliae), white-beaked dolphins (Lagenorhynchus albirostris) and harbour porpoises (Phocoena phocoena) from some or all of the 2007, 2009 and 2016 surveys. The relative abundance of most species was comparatively low in the spring and fall, and peaked June and July when all of the main surveys have been carried out. An analysis of changes in line transect density as an index of relative abundance from all surveys indicates that common minke whale abundance decreased by 75% after 2001 and has remained at a relatively low level since then. Relative abundance of humpback whales and white-beaked dolphins has increased over the period 1986-2016. We place these observed changes in context with oceanographic and ecosystem changes documented over the same period.

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Trends in the distribution and abundance of cetaceans from aerial surveys in Icelandic coastal waters, 1986-2001

NAMMCO Scientific Publications ◽

10.7557/3.2710 ◽

2009 ◽

Vol 7 ◽

pp. 117 ◽

Cited By ~ 13

Author(s):

Daniel G Pike ◽

Charles GM Paxton ◽

Thorvaldur Gunnlaugsson ◽

Gísli A Víkingsson

Keyword(s):

Relative Abundance ◽

Minke Whale ◽

Humpback Whales ◽

Line Transect ◽

Survey Area ◽

Balaenoptera Acutorostrata ◽

The North ◽

Aerial Surveys ◽

Minke Whales ◽

Abundance Estimates

Aerial surveys were carried out in coastal Icelandic waters 4 times between 1986 and 2001 as part of the North Atlantic Sightings Surveys. The surveys had nearly identical designs in 3 of the 4 years. The target species was the minke whale (Balaenoptera acutorostrata) but all species encountered were recorded. Sighting rate and density from line transect analysis were used as indices of relative abundance to monitor trends over the period, and abundance estimates corrected for perception biases were calculated for some species from the 2001 survey. More than 11 species were sighted, of which the most common were the minke whale, humpback whale (Megaptera novaeangliae), dolphins of genus Lagenorhychus, and the harbour porpoise (Phocoena phocoena). Minke whales anddolphins showed little change in distribution or abundance over the period. There were an estimated 31,653 (cv 0.30) dolphins in the survey area in 2001. Humpback whales increased rapidly at a rate of about 12%, with much of the increase occurring off eastern and northeastern Iceland. In 2001 there were an estimated 4,928 (cv 0.463) humpback whales in the survey area. The relative abundance of harbour porpoises decreased over the period, but estimates for this species were compromised by uncorrected perception biases and poor coverage. The ecological and historical significance of these findings with respect to previous whaling activities and present-day fisheries is discussed.

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Use of underwater video to assess freshwater fish populations in dense submersed aquatic vegetation

Marine and Freshwater Research ◽

10.1071/mf13230 ◽

2015 ◽

Vol 66 (1) ◽

pp. 10 ◽

Cited By ~ 11

Author(s):

Kyle L. Wilson ◽

Micheal S. Allen ◽

Robert N. M. Ahrens ◽

Michael D. Netherland

Keyword(s):

Relative Abundance ◽

Largemouth Bass ◽

Aquatic Vegetation ◽

Micropterus Salmoides ◽

Hydrilla Verticillata ◽

Submersed Aquatic Vegetation ◽

Underwater Video ◽

Point Counts ◽

Abundance Estimates ◽

Total Fish

Underwater video cameras (UVC) provide a non-lethal technique to sample fish in dense submersed aquatic vegetation. Fish often inhabit densely vegetated areas, but deficiencies of most sampling gears bias relative abundance estimates that inform fisheries management. This study developed methods using UVC to estimate relative abundance in dense vegetation using three experimental ponds covered with surface-matted hydrilla (Hydrilla verticillata) stocked at different densities of Lepomis spp. and largemouth bass (Micropterus salmoides). We conducted UVC point counts over 13 weeks to measure relative fish abundance and occurrence from video analysis. Ponds were then drained to obtain true fish densities. In total, fish were detected in 55% of all counts and juvenile and adult Lepomis spp. and largemouth bass were enumerated. End-of-season true fish densities ranged across ponds (from 52 to 37000 fishha–1). Additionally, pond 2’s true density changed substantially from 370 to 12300 fishha–1. True population size was accurately reflected in differences in estimated relative abundances obtained from fish counts, as in pond 2 where mean fish counts increased from 0.10 in week 1 to 2.33 by week 13. Underwater video accurately and precisely quantified relative abundance at naturally-occurring fish densities, but this success was reduced at low densities.

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Accounting for spatial dependence improves relative abundance estimates in a benthic marine species structured as a metapopulation

Fisheries Research ◽

10.1016/j.fishres.2021.105960 ◽

2021 ◽

Vol 240 ◽

pp. 105960

Author(s):

Joaquin Cavieres ◽

Cole C. Monnahan ◽

Aki Vehtari

Keyword(s):

Relative Abundance ◽

Spatial Dependence ◽

Marine Species ◽

Abundance Estimates

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A standardised monitoring protocol for the black caiman (Melanosuchus niger)

Wildlife Research ◽

10.1071/wr19135 ◽

2020 ◽

Vol 47 (4) ◽

pp. 317

Author(s):

Adrián Naveda-Rodríguez ◽

Víctor Utreras B. ◽

Galo Zapata-Ríos

Keyword(s):

Relative Abundance ◽

Survey Design ◽

Conservation Status ◽

Absolute Abundance ◽

Imperfect Detection ◽

Monitoring Protocol ◽

Abundance Estimates ◽

Consistent Manner ◽

Status Assessment ◽

The Individual

Abstract ContextEstimating population abundance can be plagued by the violation of methodological assumptions, which can be overcome with standardised protocols. The black caiman (BC) is considered a conservation-dependent species, and previous abundance estimates are surrounded by uncertainty and flaws in the survey (e.g. different survey design and efforts) and analytical approach used (e.g. relative abundance index, which ignores imperfect detection). Its conservation status assessment demands the implementation of a standardised monitoring protocol. AimsThe protocol provides guidelines to collect and analyse data in a consistent manner to survey BC. Besides accounting for imperfect detection to produce reliable abundance estimates, the protocol aimed to be easily implemented by park rangers, and to fit field observations into a hierarchical modelling approach to assess how environmental variables affects detectability and abundance. MethodsThe protocol subdivides a 20-km transect into 10 2-km segments; each transect is surveyed four consecutive nights, starting at 1900 hours and finishing when the 20km are completed. For each caiman detected, the observers estimated head size to classify the individual by age. We tested the protocol in Ecuador during January and December 2017, and field data were analysed using N-mixture models. We compared abundance estimates derived with this protocol with commonly used relative abundance indexes. Key resultsWe surveyed 460km that resulted in 177 detections. Percentage of moonlight and distance from human settlement best explained detectability and abundance respectively. Mean detection probability was 0.14 (95% BCI: 0.1–0.18), whereas absolute abundance was 196 (95% BCI: 147–370). The overall adult to immature ratio was 1:1.3. ConclusionsThis is the first estimate of detectability and absolute abundance for BC by using a standardised survey with a clearly defined and repeatable survey and analysis methods. Relative abundance indexes did not reflect absolute abundance estimates. We recommend the use of this protocol in future surveys across the Amazon region to effectively evaluate BC conservation status. ImplicationsPopulation size cannot be estimated from relative abundance indexes; they lead to bias estimates for ignoring imperfect detection. We discourage the use of relative abundance indexes to evaluate the conservation status of this species.

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