scholarly journals Abundance, density, and social structure of African forest elephants (Loxodonta cyclotis) in a human-modified landscape in southwestern Gabon

2019 ◽  
Author(s):  
Colin M. Brand ◽  
Mireille B. Johnson ◽  
Lillian D. Parker ◽  
Jesús E. Maldonado ◽  
Lisa Korte ◽  
...  
Keyword(s):  
Social Behavior ◽  
Population Size ◽  
Conservation Status ◽  
Keystone Species ◽  
Limited Information ◽  
Mitochondrial Haplotypes ◽  
Industrial Corridor ◽  
Forest Elephants ◽  
Loxodonta Cyclotis ◽  
Forest Elephant

AbstractThe noninvasive monitoring of population size and demography is critical to effective conservation, but forest living taxa can be difficult to directly observe due to elusiveness and/or inaccessible habitat. This has been true of African forest elephants (Loxodonta cyclotis), for which we have limited information regarding population size and social behavior despite their threatened conservation status. In this study, we estimated demographic parameters focusing specifically on population size and density using genetic capture-recapture of forest elephants in the southern Industrial Corridor of the Gamba Complex of Protected Areas, which is considered a global stronghold for forest elephants in southwestern Gabon. Additionally, we examined forest elephant sociality through analysis of social networks, predicting that we would find matrilineal structure as exhibited by savanna elephants and other forest elephants. Given 95% confidence intervals, we estimate the size of the population in the sampled area to be between 754 and 1,502 individuals and our best density estimate ranges from 0.47 to 0.80 elephants per km2. When extrapolated across the entire Industrial Corridor, this estimate suggests an elephant population size of 3,033 to 6,043 in this area based on abundance or 1,684 to 2,832 based on density, which is 40 – 83% smaller than previously suggested. Furthermore, our social network analysis revealed approximately half of network components included females with different mitochondrial haplotypes; this suggests a wider range of variation in forest elephant sociality than has previously been reported. This study emphasizes the threatened status of forest elephants and demonstrates the need to further refine baseline estimates of population size and knowledge on social behavior in this taxon, both of which will aid in determining how population dynamics in this keystone species may be changing through time in relation to increasing conservation threats.

scholarly journals Combining local knowledge and occupancy analysis for a rapid assessment of the forest elephant Loxodonta cyclotis in Cameroon's timber production forests

Oryx ◽  
2018 ◽  
Vol 54 (1) ◽  
pp. 90-100 ◽  
Author(s):  
Stephanie Brittain ◽  
Madeleine Ngo Bata ◽  
Paul De Ornellas ◽  
E. J. Milner-Gulland ◽  
Marcus Rowcliffe
Keyword(s):  
Large Scale ◽  
Population Change ◽  
Demographic Data ◽  
Rapid Assessment ◽  
Occupancy Models ◽  
Spatial And Temporal Patterns ◽  
Conservation Action ◽  
Forest Elephants ◽  
Loxodonta Cyclotis ◽  
Forest Elephant

AbstractInformation on the distribution and abundance of the forest elephant Loxodonta cyclotis is needed to allocate limited resources appropriately and set conservation goals for the species. However, monitoring at large scales in forest habitats is complicated, expensive and time consuming. We investigated the potential of applying interview-based occupancy analysis as a tool for the rapid assessment of the distribution and relative abundance of forest elephants in eastern Cameroon. Using single-season occupancy models, we explored the covariates that affect forest elephant occupancy and detectability, and identified spatial and temporal patterns in population change and occupancy. Quantitative and qualitative socio-demographic data offer additional depth and understanding, placing the occupancy analysis in context and providing valuable information to guide conservation action. Detectability of forest elephants has decreased since 2008, which is consistent with the decline in perceived abundance in occupied sites. Forest elephants occupy areas outside protected areas and outside the known elephant range defined by IUCN. Critical conservation attention is required to assess forest elephant populations and the threats they face in these poorly understood areas. Interview-based occupancy analysis is a reliable and suitable method for a rapid assessment of forest elephant occupancy on a large scale, as a complement to, or the first stage in, a monitoring process.

scholarly journals The status of the Hoopoe (Upupa epops) in Hungary: a review

2015 ◽  
Vol 23 (2) ◽  
pp. 1-9
Author(s):  
Gergő Halmos ◽  
Károly Nagy ◽  
Zsolt Karcza ◽  
Tibor Szép
Keyword(s):  
Population Size ◽  
Great Plains ◽  
Conservation Status ◽  
Population Level ◽  
Limited Information ◽  
Widespread Species ◽  
The Status ◽  
Bird Census ◽  
Loop Migration ◽  
Size Dispersion

Abstract The Hoopoe is a widespread species in Hungary with the strongest populations on the Great plains. The fact that in 2015 it became ‛The Bird of the Year’ in Hungary offers the possibility to summarise the information about the distribution, population size, dispersion, migration as well as the nature conservation status of the Hoopoe population breeding in Hungary. In the period of 1999–2014 the number of breeding pairs and trend of population level was estimated based on the Common Bird Census database. The population size was estimated as 13,500–17,500 pairs with a stable trend (slope=−1.3%, SE=2.5%) over 1999–2014. There is very limited information on migration from bird ringing, only 8 recoveries between 1928–1963 indicate, that the Hungarian population is migrating on a south-southeast direction in autumn, wintering in the eastern parts of the Sahel, possibly in Chad and Sudan and migrates back in spring following a loop migration pattern further to the east. The main conservation issues are agricultural intensification impacting feeding possibilities, lack of nesting cavities and hunting during migration.

scholarly journals Giant otter Pteronura brasiliensis density and abundance in Llanos Orientales de Colombia in the Orinoco basin

Oryx ◽  
2020 ◽  
pp. 1-4
Author(s):  
Germán Garrote ◽  
Beyker Castañeda ◽  
Jose Manuel Escobar ◽  
Laura Pérez ◽  
Brayan Marín ◽  
...  
Keyword(s):  
South America ◽  
Population Size ◽  
20Th Century ◽  
Conservation Status ◽  
Species Conservation ◽  
Iucn Red List ◽  
Red List ◽  
Recreational Fishing ◽  
Pteronura Brasiliensis ◽  
Direct Counts

Abstract The giant otter Pteronura brasiliensis, categorized as Endangered on the IUCN Red List, was once widely distributed throughout South America. By the middle of the 20th century the giant otter had become locally extinct along the main rivers of the Orinoco basin. Although some populations seem to have recovered, the paucity of information available does not permit a full evaluation of the species' conservation status. The objective of this study was to estimate the abundance and density of the giant otter population along the Orinoco river in the municipality of Puerto Carreño, Vichada, Colombia, where there is important commercial and recreational fishing. Thirty-nine linear km were surveyed, repeatedly, with a total of 315 km of surveys. Population size was estimated by direct counts of individuals. All individuals detected were photographed and identified individually from their throat pelage patterns. In total, 30 otters were identified, giving a minimum density of 0.77 individuals per km, one of the highest reported for the species in Colombia. Given the high density in this well-developed area, our results highlight the importance of this population for the conservation of the species.

scholarly journals An assessment of the distribution, population size and conservation status of the Santa Marta Foliage-gleaner Automolus rufipectus: a Sierra Nevada de Santa Marta endemic

2015 ◽  
Vol 25 (4) ◽  
pp. 451-465 ◽  
Author(s):  
ESTEBAN BOTERO-DELGADILLO ◽  
NICHOLAS BAYLY ◽  
CAMILA GÓMEZ ◽  
PAULO C. PULGARÍN-R. ◽  
CARLOS ANDRÉS PÁEZ
Keyword(s):  
Population Size ◽  
Sierra Nevada ◽  
Forest Cover ◽  
Conservation Status ◽  
Bird Species ◽  
Environmental Niche ◽  
Coffee Plantations ◽  
Habitat Transformation ◽  
Elevation Range ◽  
Area Of Occupancy

SummaryThe Santa Marta Foliage-gleaner Automolus rufipectus is one of 19 endemic bird species found in the Sierra Nevada de Santa Marta (SNSM) in northern Colombia but until recently it was considered a sub-species of the Ruddy Foliage-gleaner Automolus rubiginosus. Consequently, published information on its distribution and ecology is lacking, and while it is classified as near- threatened, this designation was based on limited quantitative data. To improve our knowledge of the Santa Marta Foliage-gleaner’s geographical distribution, elevation range, population density, habitat use and conservation status, we analysed both historical and recent site locality records and carried out variable distance transects within forested habitats and shade coffee plantations. We modelled the environmental niche of the species and subsequently estimated its extent of occurrence and area of occupancy, as well as population size. Our results consistently showed that the distribution of the Santa Marta Foliage-gleaner is more restricted than previously considered, both geographically and by elevation (we redefine elevation range as 600–1,875 m). This suggests that the species is more at risk of habitat transformation and combined with our estimates of population size (< 10,000 individuals), it is likely that the species will be uplisted to a higher threat category. More positively, and contrary to published accounts, we found that approximately 40% of the species’ range lies within protected areas. Nevertheless, we recommend the implementation of strategies to maintain forest cover on the western flank of the SNSM and further research to better define the species’ habitat needs and population dynamics.

scholarly journals Update of distribution, habitats, population size, and threat factors for the West African crocodile in Mauritania

2016 ◽  
Vol 37 (3) ◽  
pp. 325-330 ◽  
Author(s):  
João Carlos Campos ◽  
Fernando Martínez-Freiría ◽  
Fábio Vieira Sousa ◽  
Frederico Santarém ◽  
José Carlos Brito
Keyword(s):  
Population Size ◽  
Conservation Status ◽  
West African ◽  
Conservation Strategies ◽  
Temperature Extremes ◽  
Local Conservation ◽  
The West ◽  
Water Abstraction ◽  
New Localities ◽  
Domestic Use

The West African crocodile (Crocodylus suchus) is an emblematic species from the Sahara-Sahel with scarce knowledge on distribution and conservation status. This study updated the knowledge on distribution, occupied habitats, population size, and factors that threaten C. suchus and its habitats in Mauritania. Five field expeditions to Mauritania (2011-2016), allowed the detection of 26 new localities, increasing by 27% the current number of all known locations (adding up to ). In most localities less than five individuals were observed, and in all visiting sites the number of observed individuals ranged from one to 23. Eleven threat factors were identified, being droughts and temperature extremes (100% localities affected) and water abstraction for domestic use and nomadic grazing (94%) the most frequent. These findings suggest that crocodiles are apparently vulnerable in Mauritania and that future local conservation strategies are needed to assure the continuity of its fragile populations and preserve their habitats.

scholarly journals Density and population viability of coastal marten: a rare and geographically isolated small carnivore

2017 ◽  
Author(s):  
Mark A Linnell ◽  
Katie Moriarty ◽  
David S Green ◽  
Taal Levi
Keyword(s):  
Population Size ◽  
Extinction Risk ◽  
Conservation Status ◽  
Population Viability Analysis ◽  
Credible Interval ◽  
The United States ◽  
Population Viability ◽  
Coastal Forests ◽  
Private Lands ◽  
Geographically Isolated

Pacific martens (Martes caurina) in coastal forests of Oregon and northern California in the United States are rare and geographically isolated, prompting a petition for listing under the Endangered Species Act. If listed, regulations have the potential to substantially influence land-use decisions and forestry on public and private lands, but no estimates of population size, density, and viability of remnant marten populations are available for evaluating their conservation status. We used GPS telemetry, territory mapping, and spatial mark-recapture to estimate population size and density within the current extent of Pacific martens in central Oregon, within coastal forest in the Oregon dunes national recreational area. We then estimated population viability at differing levels of human-caused mortality (e.g. roadkill). We estimated 63 adult martens (95% Credible Interval: 58-73) and 73 (range: 46-91) potential territories across two subpopulations separated by a large barrier (Umpqua River). Marten density was 1.02 per km2, the highest reported in North America. Using population viability analysis, extinction risk for a subpopulation of 30 martens ranged from 34% to 100% with two or more annual human-caused mortalities. Absent broad-scale restoration of forest to conditions which support marten populations, limiting human-caused mortalities would likely have the greatest conservation impact.

scholarly journals Dramatic decline of François' langur Trachypithecus francoisi in Guangxi Province, China

Oryx ◽  
2007 ◽  
Vol 41 (1) ◽  
pp. 38-43 ◽  
Author(s):  
Youbang Li ◽  
Chengming Huang ◽  
Ping Ding ◽  
Zheng Tang ◽  
Chris Wood
Keyword(s):  
Population Size ◽  
Conservation Status ◽  
Guangxi Province ◽  
Isolated Populations ◽  
Term Survival ◽  
Management Planning ◽  
Management Measures ◽  
Species Survival ◽  
Dramatic Decline ◽  
Trachypithecus Francoisi

Interviews with local people and a survey were carried out in 23 counties of south-west Guangxi Province from April 2002 to June 2003 to evaluate the conservation status of François' langur Trachypithecus francoisi and assess the extent and nature of threats to the species' survival. François' langurs were found in only 10 counties compared with their presence in 23 counties before 1990. The total population size is estimated to be 307 individuals in 14 isolated populations. This represents a 90% decrease in population size since the early 1980s and an 85% decrease since the mid 1990s. The primary threat to the langur is hunting, mainly for traditional medicine. Our results suggest that conservation efforts for the species have been ineffectual during the last decade and, even within reserves, few direct management measures seem to have been taken to protect and conserve the langurs. Without the instigation of such measures it seems likely that François' langur will disappear both inside and outside reserves. To ensure the long-term survival of Francois' langur in Guangxi Province increased investment and improved management, planning, and training of reserve managers and staff is required, with a particular focus on the key remaining reserves and sites for the langur. Some of this work is now underway.

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