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.

scholarly journals Conservation priorities in an endangered estuarine seahorse are informed by demographic history

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Thomas Kalama Mkare ◽  
Bettine Jansen van Vuuren ◽  
Peter R. Teske
Keyword(s):  
Genetic Diversity ◽  
Population Size ◽  
Demographic History ◽  
Conservation Status ◽  
Limited Range ◽  
The Other ◽  
Conservation Priorities ◽  
Population Declines ◽  
Term Survival

AbstractHistorical demographic events shape genetic diversity that remains evident in the genomes of contemporary populations. In the case of species that are of conservation concern, this information helps to unravel evolutionary histories that can be critical in guiding conservation efforts. The Knysna seahorse, Hippocampus capensis, is the world’s most endangered seahorse species, and it presently survives in only three estuaries on the South African south coast. Factors that contributed to the species becoming endangered are unclear; additionally, the lack of information on whether the three populations should be managed separately because of potential long-term isolation hampers effective management efforts. In the present study, we reconstructed the seahorses’ demographic history using a suite of microsatellite loci. We found that the largest population (Knysna Estuary) has colonised the other estuaries relatively recently (< 450 years ago), and that its population size is comparatively large and stable. Neither of the other two populations shows signs of long-term reductions in population size. The high conservation status of the species is thus a result of its limited range rather than historical population declines. Our findings indicate that the long-term survival of H. capensis depends primarily on the successful management of the Knysna population, although the other estuaries may serve as reservoirs of genetic diversity.

scholarly journals Defining favourable reference values for bird populations in Italy: setting long-term conservation targets for priority species

2010 ◽  
Vol 21 (1) ◽  
pp. 107-118 ◽  
Author(s):  
MATTIA BRAMBILLA ◽  
MARCO GUSTIN ◽  
CLAUDIO CELADA
Keyword(s):  
Population Size ◽  
Reference Values ◽  
Spatial Scales ◽  
Conservation Status ◽  
Bird Species ◽  
Population Viability Analysis ◽  
Breeding Density ◽  
Isolated Populations ◽  
Conservation Targets

SummarySetting favourable reference values (FRV) for conservation targets may help in assessing the conservation status of species and habitats. FRVs should be expressed through population size or demographic parameters that are likely to ensure the long-term persistence of a species across its range. We developed a conceptual framework for defining FRVs for Italian birds included in Annex I of the European Union’s Wild Birds Directive 79/409/CEE. The approach was based on demographic trends, current population size and the minimum viable population concept. We subdivided bird species according to abundance at the national scale, spatial distribution in discrete isolated populations and/or biogeographic categories. FRVs based on population viability analysis (PVA) were provided for populations of less than 2,500 pairs. For species with more than 2,500 pairs and a wide, more or less continuous range, the FRV was expressed in terms of breeding density at different spatial scales for non-colonial species. Out of the 88 species considered, we were able to formulate FRVs based on PVA for 47 populations belonging to 21 species, and breeding density for 15 further species; lack of adequate data prevented us from defining FRVs for the remaining species. Further work should focus on the translation of FRV density values into population size and on the definition of reference values for range and habitat.

scholarly journals Purging of highly deleterious mutations through severe bottlenecks in Alpine ibex

2019 ◽  
Author(s):  
Christine Grossen ◽  
Frederic Guillaume ◽  
Lukas F. Keller ◽  
Daniel Croll
Keyword(s):  
Deleterious Mutation ◽  
Conservation Status ◽  
Population Bottlenecks ◽  
Deleterious Mutations ◽  
Population Declines ◽  
Mutation Load ◽  
Current Conservation ◽  
Term Survival ◽  
Alpine Ibex ◽  
Species Survival

AbstractHuman activity caused dramatic population declines in many wild species. The resulting bottlenecks have a profound impact on the genetic makeup of a species with unknown consequences for health. A key genetic factor for species survival is the evolution of deleterious mutation load, but how bottleneck strength and mutation load interact lacks empirical evidence. Here, we take advantage of the exceptionally well-characterized population bottlenecks of the once nearly extinct Alpine ibex. The species survived one of the most dramatic bottlenecks known for successfully restored species. We analyze 60 complete genomes of six ibex species and the domestic goat. We show that historic bottlenecks rather than the current conservation status predict levels of genome-wide variation. By retracing the recolonization of the Alps by Alpine ibex, we find genomic evidence of concurrent purging of highly deleterious mutations but accumulation of mildly deleterious mutations. This demonstrates how human-induced severe bottlenecks caused both relaxed selection and purging, thus reshaping the landscape of deleterious mutation load. Our findings also highlight that even populations of ~1000 individuals can accumulate mildly deleterious mutations. Hence, conservation efforts should focus on preventing population declines below such levels to ensure long-term survival of species.

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 Small population size and low genomic diversity have no effect on fitness in experimental translocations of a wild fish

2019 ◽  
Vol 286 (1916) ◽  
pp. 20191989 ◽  
Author(s):  
M. C. Yates ◽  
E. Bowles ◽  
D. J. Fraser
Keyword(s):  
Genetic Diversity ◽  
Body Size ◽  
Population Size ◽  
Brook Trout ◽  
Habitat Degradation ◽  
Species Conservation ◽  
Empirical Work ◽  
Genomic Diversity ◽  
Effective Population ◽  
Isolated Populations

Little empirical work in nature has quantified how wild populations with varying effective population sizes and genetic diversity perform when exposed to a gradient of ecologically important environmental conditions. To achieve this, juvenile brook trout from 12 isolated populations or closed metapopulations that differ substantially in population size and genetic diversity were transplanted to previously fishless ponds spanning a wide gradient of ecologically important variables. We evaluated the effect of genome-wide variation, effective population size ( N e ), pond habitat, and initial body size on two fitness correlates (survival and growth). Genetic variables had no effect on either fitness correlate, which was determined primarily by habitat (pond temperature, depth, and pH) and initial body size. These results suggest that some vertebrate populations with low genomic diversity, low N e , and long-term isolation can represent important sources of variation and are capable of maintaining fitness in, and ultimately persisting and adapting to, changing environments. Our results also reinforce the paramount importance of improving available habitat and slowing habitat degradation for species conservation.

scholarly journals Natura 2000 sites and fisheries in German offshore waters

2008 ◽  
Vol 66 (1) ◽  
pp. 155-169 ◽  
Author(s):  
Søren Anker Pedersen ◽  
Heino Fock ◽  
Jochen Krause ◽  
Christian Pusch ◽  
Anne L. Sell ◽  
...  
Keyword(s):  
Marine Mammals ◽  
Fishery Management ◽  
Conservation Status ◽  
Natura 2000 ◽  
Management Measures ◽  
Favourable Conservation Status ◽  
Management Plans ◽  
Natura 2000 Site ◽  
Environmentally Sound ◽  
Fishing Impacts

Abstract Pedersen, S. A., Fock, H., Krause, J., Pusch, C., Sell, A. L., Böttcher, U., Rogers, S. I., Sköld, M., Skov, H., Podolska, M., Piet, G. J., and Rice, J. C. 2009. Natura 2000 sites and fisheries in German offshore waters.–ICES Journal of Marine Science, 66: 155–169. The principal objective of sites selected as part of Natura 2000 is to achieve or maintain a favourable conservation status of habitats and species named in the EU Birds and Habitats directives. In the German exclusive economic zone, the habitat types protected by this legislation are sandbanks and reefs; protected species include marine mammals, seabirds, and specific migratory fish species. The ICES project Environmentally Sound Fishery Management in Protected Areas (EMPAS) aims to answer two questions: (i) To what extent do specific fishing activities significantly threaten attainment of the conservation objectives of the Natura 2000 sites? (ii) What management measures would reduce these conflicts and how effective would they be at helping to ensure the favourable condition of these sites? Assessments of fishing impacts on Natura 2000 sites require basic data on the conservation status of individual habitats and species, as well as data for fine-scale distributions of ongoing fishing activities. This paper describes and discusses the process used by the EMPAS project in developing fishery-management plans for each Natura 2000 site in German offshore waters.

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.

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