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

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.

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Out of the darkness: the first comprehensive survey of the Critically Endangered Anjouan Scops Owl Otus capnodes

Bird Conservation International ◽

10.1017/s0959270914000185 ◽

2014 ◽

Vol 25 (3) ◽

pp. 322-334 ◽

Cited By ~ 1

Author(s):

KATHLEEN E. GREEN ◽

BRONWEN M. DANIEL ◽

SAMUEL P. LLOYD ◽

ISHAKA SAID ◽

AMELAID HOUMADI ◽

...

Keyword(s):

Population Size ◽

Conservation Status ◽

Distance Sampling ◽

Bird Species ◽

Iucn Red List ◽

Critically Endangered ◽

Encounter Rate ◽

Wet Season ◽

Point Counts ◽

Comprehensive Survey

SummaryAlthough birds are among the best studied taxa, many of the globally threatened species lack the information required to fully assess their conservation status and needs. One such species is the Anjouan Scops Owl Otus capnodes which was presumed extinct until its rediscovery to science in 1992. Based on the limited extent and decline of the moist forests in the highlands of Anjouan in the Comoro Islands, a population size of only 100–200 pairs was estimated and the species was classified as ‘Critically Endangered’. The current study is the first comprehensive survey ever conducted on this species, and aimed to establish the current distribution and population size. Point counts with distance sampling were conducted across the agroforestry and forest zones of Anjouan in both a dry and wet season. A niche suitability model predicted the species distribution to be wider than expected with owls observed as low as 300 m altitude and in highly modified agroforestry habitats. However, the encounter rate in natural relatively undisturbed forest was significantly greater than in other habitats. The wider than expected geographic range of O. capnodes supports a possible downlisting of this species on the IUCN Red List to ‘Endangered’. Population size was found to be far greater than previously thought, at approximately 3,450 individual owls in the dry season and 5,450 in the wet season. These results show the importance of investing in robust surveys of poorly known and cryptic bird species, and provide up to date and important information for landscape scale conservation planning in the Comoros Islands.

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Conservation status of birds on Mindoro, Philippines

Bird Conservation International ◽

10.1017/s0959270900002513 ◽

1992 ◽

Vol 2 (4) ◽

pp. 303-325 ◽

Cited By ~ 3

Author(s):

Guy C. L. Dutson ◽

Tom D. Evans ◽

Thomas M. Brooks ◽

Desiderio C. Asane ◽

Robert J. Timmins ◽

...

Keyword(s):

Forest Cover ◽

Conservation Status ◽

Bird Species ◽

Concerted Action ◽

Medium Term ◽

Lowland Forest ◽

Risk Of Extinction ◽

Forest Remnants ◽

The Status

SummaryFour weeks of fieldwork in the forests of Mindoro, Philippines, in 1991 has elucidated the status of the six bird species endemic to the island. Of these, Ducula mindorensis and Otus mindorensis are high-altitude species with restricted ranges and in need of active conservation in the medium term. Three of the four lowland species, Gallicolumba platenae, Centropus steerü and Penelopides mindorensis are under immediate threat of extinction through forest clearance and fragmentation, while the fourth, Dicaeum retrocinctum, s i not under immediate threat but is certainly at risk of extinction in the long term. Whilst deforestation is an enormous problem across the entire Philippines, Mindoro is the smallest centre of endemism with the least forest cover after the Sulu Islands. Extinctions are believed inevitable within the next 10 years unless concerted action is urgently taken. The Halcon range must receive attention in order to conserve the montane species, but more urgent by far is the preservation of lowland forest remnants, concentrating on central-west Mindoro.

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An estimate of the area of occupancy and population size of Brachycephalus tridactylus (Anura: Brachycephalidae) to reassess its conservation status, with a proposal for conservation measures

PeerJ ◽

10.7717/peerj.12687 ◽

2021 ◽

Vol 9 ◽

pp. e12687

Author(s):

Marcos R. Bornschein ◽

Júnior Nadaline ◽

Luiz Fernando Ribeiro ◽

Giovanna Sandretti-Silva ◽

Maria Fernanda Ferreira Rivas ◽

...

Keyword(s):

New Species ◽

Population Size ◽

Conservation Status ◽

Species Conservation ◽

Type Locality ◽

Area Of Occupancy ◽

Conservation Measures ◽

New Localities ◽

Species Population ◽

Surrounding Areas

Background We are experiencing a global crisis in conservation, which has led to the prioritization of targets, such as nations, regions, and animal groups, which are necessary while resources are disputed. Brazil is a priority not only because of its megadiversity, high rates of endemism, and frequent descriptions of new species but also because of its high levels of deforestation. Among the species groups prioritized for conservation is the anurans (Amphibia: Anura), the population of which is severely declining. One group of anurans is the genus Brachycephalus, which includes 37 endemic species in the Brazilian Atlantic Rainforest. Some of these species have highly restricted distributions (<100 ha). Thirty new species have been described since 2000, and 55.3% of all species are threatened with extinction. Brachycephalus tridactylus was only recently described and remains restricted to its type locality. Because of its reduced geographical distribution (0.41 km2), it has been proposed to be considered as Vulnerable. The objective of this study is to reevaluate the conservation status of Brachycephalus tridactylus and propose conservation measures. Methods We searched for new populations during 2016–2020, evaluated in loco impacts and potential impacts on the species’ population, and performed an analysis of the density of this population and estimated its size. International Union for Conservation of Nature (IUCN) criteria were used to assess the conservation status of the species. Results We recorded the species in seven new localities (from 715–1,140 m above sea level) in the state of São Paulo up to 33 km from the type locality of the species (in state of Paraná). We estimated the area of occupancy as 148.44 km2, densities as one calling male per 4.05 m2 and 130.00 m2, and a total population size of 4,429,722 adult individuals. Based on our finding, we proposed three lines of management: (1) formation of fire brigades, (2) management of residents’ mules in the conservation unit and surrounding areas, and (3) management of degraded areas. We recommend changing the species’ conservation status from Vulnerable to Endangered because of its fragmented distribution and decline in the area of occupancy and in the quality of its habitat. Our results have expanded the species previous geographic distribution and delimited areas without previous records. Our estimates of population density and size are in accordance with those verified for congeners. The conservation of this species benefits the environments and other species that inhabit them, being, therefore, strategic for receiving conservation actions that will spread throughout the ecosystem.

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Conservation status and recovery of Podocarpus angustifolius: a threatened tree of Cuba

Oryx ◽

10.1017/s0030605321000144 ◽

2021 ◽

pp. 1-3

Author(s):

Ernesto Testé ◽

Majela Hernández ◽

Eldis R. Bécquer ◽

Oliver Valle ◽

Luis R. González-Torres

Keyword(s):

Protected Areas ◽

Size Structure ◽

Conservation Status ◽

Population Based ◽

Iucn Red List ◽

Small Population ◽

Red List ◽

Coffee Plantations ◽

Area Of Occupancy ◽

In The Wild

Abstract The recovery of species’ populations is one of the most challenging tasks in conservation, which is why species recovery is most likely to be successful if it involves as many stakeholders as possible. Podocarpus angustifolius, a tree endemic to Cuba, is potentially threatened by overexploitation, deforestation and expansion of exotic species. In December of 2017, in two protected areas containing the only known subpopulations of this species, we recorded the geographical position, height, and diameter at breast height of each individual, and calculated the extent of occurrence (EOO) and area of occupancy (AOO). We recorded a total of 575 individuals, 174 of which were adult (defined as ≥ 6 m height on the basis of the occurrence of reproductive structures), and most of which occurred in Lomas de Banao Ecological Reserve. The EOO and AOO were 125.8 km2 and 6.0 km2, respectively. All P. angustifolius that remain in the wild are within two protected areas, either in rainforest relicts or in coffee plantations. The size structure indicates a growing population. Based on our findings we recommend that P. angustifolius should be recategorized from Vulnerable (on the IUCN Red List) and Critically Endangered (on the national Red List) to Endangered, based on criterion D (small population size). We recommend the continued reinforcement of the population at Topes de Collantes Natural Protected Landscape and the continued engagement of local stakeholders for the long-term conservation of this species.

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Status assessment of the Critically Endangered Azores Bullfinch Pyrrhula murina

Bird Conservation International ◽

10.1017/s0959270911000025 ◽

2011 ◽

Vol 21 (4) ◽

pp. 477-489 ◽

Cited By ~ 9

Author(s):

RICARDO S. CEIA ◽

JAIME A. RAMOS ◽

RUBEN H. HELENO ◽

GEOFF M. HILTON ◽

TIAGO A. MARQUES

Keyword(s):

Population Size ◽

Conservation Status ◽

Distance Sampling ◽

Iucn Red List ◽

Range Size ◽

Critically Endangered ◽

Survey Method ◽

Mountain Range ◽

Laurel Forest ◽

Area Of Occupancy

SummaryThe Azores Bullfinch is endemic to the island of São Miguel (Azores, Portugal). Its status was uplisted to Critically Endangered in 2005 on the basis of an extremely small and declining population that was considered to be restricted to a very small mountain range (43 km2), in a single location, within which the spread of invasive plants constituted a threat to habitat quality. Nevertheless, information was mostly inferred, or the product of, non-systematic studies. In order to carry out a complete assessment of the conservation status we analysed: (i) population trend, calculated from annual monitoring 1991–2008, (ii) population size, and (iii) range size, obtaining estimates in a single morning study in 2008 involving the simultaneous participation of 48 observers. Contrary to previous inferences, the population is no longer decreasing, although quality of laurel forest habitat continues to decline due to the persistent threat of invasive species. Population size (mean ± SE) was estimated at 1,064 ± 304 individuals using distance sampling methods, although the estimate was very sensitive to the survey method used. Range size estimates (extent of occurrence and area of occupancy) were 144 km2 and 83 km2 respectively. Given the present information, we propose the downlisting of Azores Bullfinch to Endangered on the IUCN Red List.

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

Bird Conservation International ◽

10.1017/s0959270910000407 ◽

2010 ◽

Vol 21 (1) ◽

pp. 107-118 ◽

Cited By ~ 8

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.

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Evaluating the conservation status of the Black-fronted Francolin Pternistis atrifrons

Bird Conservation International ◽

10.1017/s0959270917000363 ◽

2017 ◽

Vol 28 (4) ◽

pp. 653-661 ◽

Cited By ~ 2

Author(s):

KAI GEDEON ◽

DENNIS RÖDDER ◽

CHEMERE ZEWDIE ◽

TILL TÖPFER

Keyword(s):

Population Size ◽

Conservation Status ◽

Field Studies ◽

Grazing Pressure ◽

Iucn Red List ◽

Southern Ethiopia ◽

Current Conservation ◽

Area Of Occupancy ◽

Conservation Actions ◽

Iucn Red List Criteria

SummaryThe occurrence of the Black-fronted Francolin Pternistis atrifrons is restricted to a tiny area in southern Ethiopia. Based on field studies from 2012 to 2014, we modelled the range and estimated the population size of the species in order to evaluate its current conservation status. Annual mean temperature (relatively low) and precipitation (relatively high) proved to be key factors for the probability of its occurrence. The modelled range is 1,286 km2 (“extent of occurrence” according to the IUCN Red List criteria). However, only about one third of the modelled range is actually populated by the Black-fronted Francolin. This area, around 385 km2, corresponds to the IUCN’s “area of occupancy”. The total population size is estimated at 1,100 to 2,100 mature individuals. Thus, we conclude that the species should be classified as Endangered, criteria: A2c+B1ab(i,iii,v) + B2ab(i,iii,v); population trend: decreasing. This means that the Black-fronted Francolin is one of Africa’s most endangered galliforms. Major threats are range and habitat losses due to agricultural expansion, grazing pressure, commercial firewood and timber exploitation, and hunting. Furthermore, expected climate changes in south-east Ethiopia (higher temperatures, less precipitation) could further exacerbate these threats. We propose urgent conservation actions, including the extension of the currently projected Borana National Park.

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Conservation biology of threatened Mediterranean chasmophytes: The case of Asperula naufraga endemic to Zakynthos island (Ionian islands, Greece)

PLoS ONE ◽

10.1371/journal.pone.0246706 ◽

2021 ◽

Vol 16 (2) ◽

pp. e0246706 ◽

Cited By ~ 1

Author(s):

Anna-Thalassini Valli ◽

Vassiliki Lila Koumandou ◽

Gregoris Iatrou ◽

Marios Andreou ◽

Vasileios Papasotiropoulos ◽

...

Keyword(s):

Genetic Diversity ◽

Population Size ◽

Extinction Risk ◽

Conservation Status ◽

Small Population ◽

Ex Situ ◽

Current Conservation ◽

Ionian Islands ◽

Small Population Size ◽

Area Of Occupancy

Asperula naufraga is a rare and threatened obligate chasmophyte, endemic to Zakynthos island (Ionian islands, Greece). In this study, we provide a combined approach (including monitoring of demographic and reproductive parameters and study of genetic diversity) to assess the current conservation status of the species and to estimate its future extinction risk. The five subpopulations of A. naufraga were monitored for five years (2014–2018). Population size markedly fluctuated between 68–130 mature individuals during the monitoring period. The extent of occurrence (EOO) was estimated at 28.7 km2 and the area of occupancy (AOO) was 8 km2. Stage-structure recordings were similar for all subpopulations, characterized by high proportions of adult and senescent individuals, following a common pattern, which has been observed in other cliff-dwelling plants. Preliminary genetic analysis with SSRs markers revealed low heterozygosity within subpopulations and significant departure from H-W equilibrium, which combined with small population size suggest increased threat of genetic diversity loss. Our results indicate that the species should be placed in the Critically Endangered (CR) IUCN threat category, while according to Population Viability Analysis results its extinction risk increases to 47.8% in the next 50 years. The small population size combined with large fluctuations in its size, low recruitment and low genetic diversity, indicate the need of undertaking effective in situ and ex situ conservation measures.

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Conservation status of the threatened and endemic Rufous-throated Dipper Cinclus schulzi in Argentina

Bird Conservation International ◽

10.1017/s0959270919000467 ◽

2019 ◽

Vol 30 (3) ◽

pp. 396-405

Author(s):

NATALIA POLITI ◽

SEBASTIÁN MARTINUZZI ◽

PATRICIA SARDINA ARAGÓN ◽

VERÓNICA MIRANDA ◽

SEBASTIÁN ALBANESI ◽

...

Keyword(s):

Population Size ◽

National Parks ◽

Potential Distribution ◽

Conservation Status ◽

Iucn Red List ◽

Red List ◽

Mountain Forest ◽

Suitable Habitat ◽

Area Of Occupancy ◽

North Western

SummaryThe Rufous-throated Dipper Cinclus schulzi is endemic to the Southern Yungas of north-western Argentina and southern Bolivia. The species is categorised as ‘Vulnerable’ on the IUCN Red List on the basis of small population size and restricted range. The purpose of our study was to determine the distribution of potentially suitable habitat for the Rufous-throated Dipper, estimate its population size, and assess potential distribution within strict protected areas, in north-western Argentina. We surveyed 44 rivers in the Southern Yungas of Argentina from 2010 to 2013 to determine dipper density (i.e. the number of individuals detected per km surveyed). The dipper’s potential distribution was assessed using a maximum entropy modeling approach based on 31 occurrence points and eight bioclimatic and two topographic variables as predictors. The species is dependent on mountain forest rivers, so the potential distribution was restricted to rivers. We estimated dipper population size by multiplying density by the potential distribution along rivers. Finally, we calculated the extent of suitable habitat contained within the boundaries of Argentina´s National Parks. Dipper density was 0.94 ± 1.55 individuals/km. We estimate that within north-west Argentina there are ~2,815 km of river that are potential habitat, with an area of occupancy of 141 km2 and a population size of 2,657 ± 4,355 dippers. However, of this river extent, less than 5% is within National Parks. Our results highlight the need to create new and to enlarge existing National Parks that protect the potentially suitable habitat of the species. Although more information is needed for Bolivia, the country-level area of occupancy and population size of the dipper found in Argentina provides strong evidence that the IUCN Red List classification of this species as ‘Vulnerable’ is warranted.

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Conservation status of the narrow endemic gypsophile Ononis tridentata subsp. crassifolia in southern Spain: effects of habitat disturbance

Oryx ◽

10.1017/s0030605312001688 ◽

2013 ◽

Vol 47 (2) ◽

pp. 199-202 ◽

Cited By ~ 5

Author(s):

Miguel Ballesteros ◽

Ana Foronda ◽

Eva María Cañadas ◽

Julio Peñas ◽

Juan Lorite

Keyword(s):

Population Size ◽

Seedling Recruitment ◽

Conservation Status ◽

Iucn Red List ◽

Endemic Plant ◽

Negative Effects ◽

Field Surveys ◽

Narrow Endemic ◽

Area Of Occupancy ◽

Species Area

AbstractOnonis tridentata L. subsp. crassifolia (Leguminosae) is a narrow endemic plant restricted to gypsum outcrops in south-east Spain. Its habitat and populations are currently threatened by anthropogenic disturbance. Because of the paucity of information concerning its distribution, abundance and response to disturbance, we assessed its status and evaluated the impacts of quarrying, ploughing, grazing and afforestation. Distribution and population size were estimated by field surveys, censuses and mapping. We measured cover, plant volume, fruit and seed production, seed predation and seedling recruitment to asses any effects of disturbance. The species’ area of occupancy is 1.6 km2 and its extent of occurrence 337 km2, in 29 habitat patches and 16 populations between 705 and 1,125 m altitude, and its population size was estimated to be 531,605. Quarrying, ploughing, overgrazing and afforestation negatively affected the species, in this order. We recommend this subspecies be categorized as Vulnerable on the IUCN Red List. A species recovery plan is required, and the ecological restoration of altered areas would mitigate negative effects on the species and improve the overall conservation of gypsum habitats.

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