Aerial mark - recapture estimates of wild horses using natural markings

2008 ◽  
Vol 35 (4) ◽  
pp. 365 ◽  
Author(s):  
Michelle J. Dawson ◽  
Cameron Miller
Keyword(s):  
National Park ◽  
High Plains ◽  
Population Estimates ◽  
Small Populations ◽  
Horse Population ◽  
Mark Recapture ◽  
Aerial Surveys ◽  
Discrete Population ◽  
Over Time

Aerial mark–recapture population estimates utilising the natural markings of wild horses to identify individuals was applied in the Bogong High Plains, Alpine National Park, Victoria. A discrete population of wild horses occupying an area of 180 km2 was sampled over two days in 2005. This study explored the feasibility of a technique that aimed to enable managers to estimate the size of the horse population and monitor it over time. Four observers (including the pilot) searched for horses from a helicopter. Once horses were sighted, photographic and written observations were used to ‘mark’ each animal. The survey was repeated the following day with observations ‘recapturing’ individuals. Data were analysed using several mark–recapture estimators, and the derived population estimates ranged from 89 (±5.3, s.e.) horses to 94.7 (±7.9, s.e.) horses. We found that the method gave a level of precision relevant to management, but needs refinement. The technique and its assumptions should be tested further by increasing the number of samples and video should be used to improve identification of individuals. We believe that this is a novel application for aerial surveys, which are typically unsuitable for estimating the size of small populations. This technique was developed for horses but may be used on other conspicuous species with unique natural markings.

Estimating brush-tailed rock-wallaby population size using individual animal recognition

2011 ◽  
Vol 33 (2) ◽  
pp. 228
Author(s):  
Karl Vernes ◽  
Stuart Green ◽  
Piers Thomas
Keyword(s):  
Population Size ◽  
National Park ◽  
New South ◽  
Morphological Characters ◽  
Population Estimates ◽  
Individual Animal ◽  
Mark Recapture ◽  
South Wales ◽  
North Eastern ◽  
Estimate Population Size

We undertook surveys of brush-tailed rock-wallabies (Petrogale penicillata) at four colonies in Oxley Wild Rivers National Park, north-eastern New South Wales, with the aim of developing a technique based upon individual animal recognition that could be used to obtain robust population estimates for rock-wallaby colonies. We identified individuals on the basis of distinct morphological characters in each colony using visual observations, and used the data within a ‘mark–recapture’ (or sight–resight) framework to estimate population size. More than 37 h of observations were made over 10 sampling days between 18 May and 9 June 2010. We could identify 91.7% of all rock-wallabies that were independently sighted (143 of 156 sightings of 35 animals). A small percentage of animals could not be identified during a visit because they were seen only fleetingly, were in dense cover, or were partly obscured by rock. The number of new animals sighted and photographed declined sharply at the midpoint of the survey, and there was a corresponding increase in resighting of known individuals. Population estimates using the mark–recapture methodology were nearly identical to estimates of total animals seen, suggesting that this method was successful in obtaining a complete census of rock-wallabies in each colony.

scholarly journals Estimating Population Densities of Black-Tailed Prairie Dogs

1994 ◽  
Vol 18 ◽  
pp. 31-34
Author(s):  
Kieth Severson ◽  
Glenn Plumb
Keyword(s):  
National Park ◽  
Correlation Coefficients ◽  
Cynomys Ludovicianus ◽  
Prairie Dogs ◽  
Population Estimates ◽  
Prairie Dog ◽  
Usda Forest Service ◽  
Mark Recapture ◽  
Black And White ◽  
Park Service

The recent black-footed ferret reintroduction into the Conata Basin area of west­central South Dakota has prompted managers of USDA Forest Service, Buffalo Gap National Grasslands and National Park Service, Badlands National Park, to reassess methods of determining population size of black-tailed prairie dogs Cynomys ludovicianus. Most agencies are currently relying on a protocol developed by Biggins et al. (1993) to assess black-footed ferret habitat, a section of which deals with prey abundance. The protocol is based on population estimates derived from counting the number of active burrows. The justification for this was a set of unpublished data that reported fair and good relationships between counts of active burrows and black- and white-tailed prairie dogs C. leucurus, respectively (Biggins et al. 1993). While there is no other correlative information relative to active burrows, Powell et al. (1994) suggested that counts of active burrows alone may not be a reliable indicator of black-tailed prairie dog populations. Menkens et al. (1988) examined relationships between populations determined by mark-recapture and total burrow counts. They reported that white­tailed prairie dog density was not significantly related to burrow density and was not a useful predictor of population density. However, Fagerstone and Biggins (1986) and Menkens et al. (1990) reported high correlation coefficients when comparing visual counts of white-tailed prairie dogs with mark-recapture densities. The purpose of this study was to examine relationships among population estimates from mark-recapture techniques with visual counts, active burrow counts, and total burrow counts derived by ground and aerial surveys all within the same experimental design.

Australian And New Zealand Fur Seals At The Skerries, Victoria: Recovery Of A Breeding Colony

2002 ◽  
Vol 24 (1) ◽  
pp. 57 ◽  
Author(s):  
CL Littnan ◽  
AT Mitchell
Keyword(s):  
New Zealand ◽  
Population Size ◽  
Arithmetic Mean ◽  
Aerial Photographs ◽  
Population Estimates ◽  
Breeding Colony ◽  
Mark Recapture ◽  
Aerial Surveys ◽  
Fur Seals ◽  
Breeding Seasons

The population size of Australian fur seals Arctocephalus pusillus doriferus and New Zealand fur seals A. forsteri at The Skerries, Victoria was estimated in two consecutive breeding seasons, 1999-2000 and 2000-2001 using both mark-recapture procedures and aerial surveys. 675 and 746 A. p. doriferus pups and 37 and 47 A. forsteri pups were captured and marked in 1999-2000 and 2000-2001, respectively. Resights (1999-2000 N = 3; 2000-2001 N = 6) were conducted 2 - 3 days after marking and pup population estimates were calculated using a modified Lincoln-Petersen estimate. The arithmetic mean for A. p. doriferus pup abundance was 1,867 in the first season and 2,237 in the second. A. forsteri abundance was 75 and 78, respectively. The A. p. doriferus population is estimated to have increased an average of 19.7% (r = 0.18) between 1999 and 2000. The arithmetic mean from five counts of aerial photographs of total animals present at the colony was 1,758 in 1999-2000 and 2,965 in 2000-2001. Due to high variation between counts, aerial surveys proved to be an inconsistent and inaccurate method for estimating the population of fur seals at The Skerries.

scholarly journals Population estimates of Antillean manatees in Puerto Rico: an analytical framework for aerial surveys using multi-pass removal sampling

2019 ◽  
Vol 100 (4) ◽  
pp. 1340-1349
Author(s):  
Jaime A Collazo ◽  
Matthew J Krachey ◽  
Kenneth H Pollock ◽  
Francisco J Pérez-Aguilo ◽  
Jan P Zegarra ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Detection Probability ◽  
Analytical Framework ◽  
Population Estimates ◽  
High Concentration ◽  
Imperfect Detection ◽  
Factors Affecting ◽  
Management Actions ◽  
Aerial Surveys ◽  
Population Size Estimates

AbstractEffective management of the threatened Antillean manatee (Trichechus manatus manatus) in Puerto Rico requires reliable estimates of population size. Estimates are needed to assess population responses to management actions, and whether recovery objectives have been met. Aerial surveys have been conducted since 1976, but none adjusted for imperfect detection. We summarize surveys since 1976, report on current distribution, and provide population estimates after accounting for apparent detection probability for surveys between June 2010 and March 2014. Estimates in areas of high concentration (hotspots) averaged 317 ± 101, three times higher than unadjusted counts (104 ± 0.56). Adjusted estimates in three areas outside hotspots also differed markedly from counts (75 ± 9.89 versus 19.5 ± 3.5). Average minimum island-wide estimate was 386 ± 89, similar to the maximum estimate of 360 suggested in 2005, but fewer than the 700 recently suggested by the Puerto Rico Manatee Conservation Center. Manatees were more widespread than previously understood. Improving estimates, locally or island-wide, will require stratifying the island differently and greater knowledge about factors affecting detection probability. Sharing our protocol with partners in nearby islands (e.g., Cuba, Jamaica, Hispaniola), whose populations share genetic make-up, would contribute to enhanced regional conservation through better population estimates and tracking range expansion.El manejo efectivo del manatí antillano amenazado en Puerto Rico requiere estimados de tamaños de poblaciónes confiables. Dichas estimaciones poblacionales son necesarias para evaluar las respuestas a las acciones de manejo, y para determinar si los objetivos de recuperación han sido alcanzados. Se han realizado censos aéreos desde 1976, pero ninguno de ellos han sido ajustados para detecciones imperfectas. Aquí resumimos los censos desde 1976, actualizamos la distribución, y reportamos los primeros estimados poblacionales ajustados para la probabilidad de detección aparente en los censos de Junio 2010 a Marzo 2014. Las estimaciones poblacionales en áreas de mayor concentración del manatí promedió 317 ± 103, tres veces más abundante que los conteos sin ajuste (104 ± 0.56). Las estimaciones poblacionales en tres áreas fuera de las áreas de mayor concentración del manatí también fueron marcadamente diferentes (75 ± 9.89 vs 19.5 ± 3.5). El estimado mínimo poblacional en la isla entera fue de 386 ± 89, similar al estimado máximo de 360 sugerido en el año 2005, pero menor a los 700 sugeridos recientemente por el Centro de Conservación de Manatíes de Puerto Rico. Documentamos que el manatí tiene una distribución más amplia de lo que se sabía con anterioridad. El mejoramiento de los estimados poblacionales locales o a nivel de isla requerirá que se estratifique a la isla en forma diferente y que se investiguen los factores que influencian a la probabilidad de detección. Compartir protocolos como este con colaboradores de islas vecinas (por. ej., Cuba, Jamaica, Española), cuyas poblaciones de manatíes comparten material genético, contribuiría a la conservación regional mediante mejores estimaciones poblacionales y monitoreo de la expansión de su ámbito doméstico.

scholarly journals The dynamics of questing ticks collected for 164 consecutive months off the vegetation of two landscape zones in the Kruger National Park (1988–2002). Part II. Rhipicephalus appendiculatus and Rhipicephalus zambeziensis

2011 ◽  
Vol 78 (1) ◽  
Author(s):  
Arthur M. Spickett ◽  
Gordon J. Gallivan ◽  
Ivan G. Horak
Keyword(s):  
Population Dynamics ◽  
Relative Humidity ◽  
National Park ◽  
Rhipicephalus Appendiculatus ◽  
Kruger National Park ◽  
Large Herbivore ◽  
Questing Ticks ◽  
Over Time

The study aimed to assess the long-term population dynamics of questing Rhipicephalus appendiculatus and Rhipicephalus zambeziensis in two landscape zones of the Kruger National Park (KNP). Ticks were collected by dragging the vegetation monthly in three habitats (grassland, woodland and gully) at two sites in the KNP (Nhlowa Road and Skukuza) from August 1988 to March 2002. Larvae were the most commonly collected stage of both species. More R. appendiculatus were collected at Nhlowa Road than at Skukuza, with larvae being most abundant from May to August, while nymphs were most abundant from August to December. Larvae were most commonly collected in the gullies from 1991 to 1994, but in the grassland and woodland habitats from 1998 onwards. Nymphs were most commonly collected in the grassland and woodland. More R. zambeziensis were collected at Skukuza than at Nhlowa Road, with larvae being most abundant from May to September, while nymphs were most abundant from August to November. Larvae and nymphs were most commonly collected in the woodland and gullies and least commonly in the grassland (p < 0.01). The lowest numbers of R. appendiculatus were collected in the mid-1990s after the 1991/1992 drought. Rhipicephalus zambeziensis numbers declined after 1991 and even further after 1998, dropping to their lowest levels during 2002. The changes in numbers of these two species reflected changes in rainfall and the populations of several of their large herbivore hosts, as well as differences in the relative humidity between the two sites over time.

scholarly journals Changes in number and distribution of hippoptamus (Hippopotamus amphibius) in the Sabie River, Kruger National Park, during the 1992 drought

Koedoe ◽  
1995 ◽  
Vol 38 (2) ◽  
Author(s):  
P.C. Viljoen
Keyword(s):  
Southern Africa ◽  
National Park ◽  
Dry Season ◽  
Kruger National Park ◽  
Population Densities ◽  
Drought Period ◽  
Aerial Surveys ◽  
Hippopotamus Amphibius ◽  
Reduced Flow

The 1991/92 drought in Southern Africa and the effect of the resultant reduced flow of the Sabie River on hippopotami was investigated. Hippopotami are counted annually in the Kruger National Park's (KNP) major rivers as part of the park's monitoring pro- gramme. Two additional aerial surveys were conducted to document changes in hippopotamus population densities in the Sabie River during the drought period. The hippopotamus population decreased during the drought by 12.6 to 672 animals between July 1991 and October 1992. The highest and lowest hippopotamus densities recorded were 11.6 and 2.2 animals/km river length respectively in different river sections. Only 12 hippopotamus mortalities were recorded at the end of the 1992 dry season (October).

scholarly journals Dispersão de Espécie Exótica no Parque Nacional da Lagoa do Peixe e Seu Entorno (Dispersion of Exotic Vegetation Into and Around the Lagoa do Peixe National Park)

2011 ◽  
Vol 4 (1) ◽  
pp. 33 ◽  
Author(s):  
Luana Portz ◽  
Rogério Portantiollo Manzolli ◽  
Dejanira Luderitz Saldanha ◽  
Iran Carlos Stalliviere Correa
Keyword(s):  
Native Species ◽  
National Park ◽  
Rio Grande ◽  
Multispectral Images ◽  
Rio Grande Do Sul ◽  
Field Verification ◽  
Exotic Vegetation ◽  
Manual Classification ◽  
Natural Dispersal ◽  
Over Time

O Parque Nacional da Lagoa do Peixe está localizado no litoral sul do estado do Rio Grande do Sul. Dentre os conflitos existentes dentro da área do parque e no seu entorno, o aumento e a dispersão da vegetação exótica, vem gerando inúmeras discussões. Neste contexto o objetivo do presente trabalho foi identificar a distribuição espacial, ao longo do tempo, das áreas de plantações de Pinus sp. Para tanto foram utilizadas imagens multiespectrais de sensoriamento remoto (TM-Landsat 5), com datas entre 1986 e 2009, sendo realizada a classificação manual por meio da vetorização, verificação de campo e análise quantitativa e qualitativa dos resultados obtidos. O problema principal da dispersão natural de Pinus sp. é encontrado na margem da lagoa principal, margeada por banhados e por pinus, cuja dispersão espontânea está competindo com o crescimento da vegetação natural e alterando o cenário típico da região. De 1986, data de criação do parque, até hoje a área de pinus, no entorno desta lagoa, cresceu de 61 para 252 ha. Este aumento da área de ocorrência de Pinus sp, em mais de 4 vezes, torna necessária a sua extração, a fim de preservar as espécies nativas da região, bem como a diversidade biológica a ela associada. A expansão da silvicultura é preocupante, pois assumiu uma grande proporção em área, não se encontrando ações que indiquem uma desaceleração deste processo. Além de diminuir o valor estético da paisagem natural esta invasão poderá comprometer o potencial turístico e principalmente de preservação ambiental ao qual o título de Parque Nacional exige.Palavras chaves: Pinus sp., Landsat, impactos. Dispersion of Exotic Vegetation Into and Around the Lagoa do Peixe National Park  ABSTRACTLagoa do Peixe National Park presents a great variety of fragile ecosystems. Among the conflicts present into and around the Park is the increase and dispersion of exotic vegetation, that is generating several discussions. In this context, the objective of this paper was identifying the spatial distribution, over time, of the Pinus sp. plantations in this area. For both researches, it was used multispectral images (Landsat), with dates between 1986 and 2009, and performed the manual classification, field verification and analysis of quantitative and qualitative results. The main problem related to the natural dispersal of Pinus sp. is found on the shore of the park’s main lagoon. This area is bordered by marshes and Pinus sp. whose spontaneous dispersion is competing with the natural vegetation and altering the typical scenery of this region. Since the creation of the park (1986) until today, the area of pinus, around the lagoon, has grown from 61 to 252 ha. This increase, more than four times, makes it necessary its extraction in order to preserve the native species and the biodiversity associated. The expansion of forestry in the Lagoa do Peixe National Park is worrisome because it has been taking a great extent of the area, and there are no actions that indicate a slowdown of this process.Keyword: Pinus sp., Landsat, impact.

Encounters on the Frontier: Banteng in Australia’s Northern Territory

2014 ◽  
Vol 22 (1) ◽  
pp. 26-41 ◽  
Author(s):  
Vanessa deKoninck
Keyword(s):  
Introduced Species ◽  
National Park ◽  
Genetic Resource ◽  
Northern Territory ◽  
Nonhuman Animal ◽  
The North ◽  
Bos Javanicus ◽  
Environmental Threat ◽  
Tropical Australia ◽  
Over Time

Abstract This paper considers the case of an introduced species that resides in what is now a jointly managed national park in the north of tropical Australia. Banteng (Bos javanicus) are a peculiar feral nonhuman animal in that they constitute a potential environmental threat within the domestic conservation goals of the park, but they also hold the prospect of being a major genetic resource in the international conservation of the species. Thus, perspectives on the use and management of these animals are varied between different actors in the park landscape, and are subject to fluctuations over time, especially in response to wider social and political circumstances. This paper argues that seemingly objective views of these animals are actually a series of subjectivities, which have less to do with any concrete aspects of the animals themselves and more to do with the way that particular people orient themselves toward, and within, the landscape.

scholarly journals Unexpected heterozygosity in an island mouflon population founded by a single pair of individuals

2006 ◽  
Vol 274 (1609) ◽  
pp. 527-533 ◽  
Author(s):  
Renaud Kaeuffer ◽  
David W Coltman ◽  
Jean-Louis Chapuis ◽  
Dominique Pontier ◽  
Denis Réale
Keyword(s):  
Genetic Diversity ◽  
Wild Population ◽  
Ovis Aries ◽  
Stochastic Simulations ◽  
Single Pair ◽  
Small Populations ◽  
Short Period ◽  
Large Populations ◽  
History Of ◽  
Over Time

In population and conservation genetics, there is an overwhelming body of evidence that genetic diversity is lost over time in small populations. This idea has been supported by comparative studies showing that small populations have lower diversity than large populations. However, longitudinal studies reporting a decline in genetic diversity throughout the whole history of a given wild population are much less common. Here, we analysed changes in heterozygosity over time in an insular mouflon ( Ovis aries ) population founded by two individuals in 1957 and located on one of the most isolated locations in the world: the Kerguelen Sub-Antarctic archipelago. Heterozygosity measured using 25 microsatellite markers has actually increased over 46 years since the introduction, and exceeds the range predicted by neutral genetic models and stochastic simulations. Given the complete isolation of the population and the short period of time since the introduction, changes in genetic variation cannot be attributed to mutation or migration. Several lines of evidence suggest that the increase in heterozygosity with time may be attributable to selection. This study shows the importance of longitudinal genetic surveys for understanding the mechanisms that regulate genetic diversity in wild populations.

scholarly journals Prospects and Constraints of Madhupur National Park Management

2012 ◽  
Vol 5 (1) ◽  
pp. 151-158
Author(s):  
MY Mia ◽  
MU Hossain ◽  
S Farzana
Keyword(s):  
Natural Resources ◽  
National Parks ◽  
National Park ◽  
Deciduous Forest ◽  
Anthropogenic Disturbances ◽  
Park Management ◽  
Reserve Forest ◽  
Agro Forestry ◽  
Over Time ◽  
Local Leaders

The study was conducted in Madhupur National Park (MNP), which is very well known for its characteristics as deciduous forest.  This study examined the constraints of park management, causes of deforestation and prospects of Madhupur Sal forests of Bangladesh. Data were collected from the Madhupur National Park authority and a study was done to have clear scenario of the park management and status of forest over time. It is evident from the study that due to various factors like anthropogenic disturbances, political abusement, absence of proper rules and regulations, willingless of the authority, encroachment of forest by locals/local leaders, illegal cutting of Sal trees, agro-forestry, and lack of adequate budget are main constraints for managing MNP. The study also revealed that about 1-3% of the forest is depleted each year, and about 50-80 years later, the forest will be completely vanished or scattered in somewhere. However, MNP will be a sustainable reserve forest for Sal trees and other flora and fauna, and also be a potential ecotourism spot, if it is properly managed. Findings of the study will help to identify the prospects and constraints of MNP and also in other National Parks in Bangladesh which ultimately conserve the biodiversity and help to maintain natural balance. DOI: http://dx.doi.org/10.3329/jesnr.v5i1.11570 J. Environ. Sci. & Natural Resources, 5(1): 151 - 158, 2012

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