Distribution, habitat and satus of the Carpentarian rock-rat, Zyzomys palatalis

1996 ◽  
Vol 23 (1) ◽  
pp. 77 ◽  
Author(s):  
SK Churchill
Keyword(s):  
Habitat Use ◽  
Population Size ◽  
Fire Regimes ◽  
Critically Endangered ◽  
Suitable Habitat ◽  
Gulf Region ◽  
Relict Vegetation ◽  
Feral Animals ◽  
Monsoon Rainforest

A survey was conducted in the Northern Temtory and Queensland to determine the distribution, status and habitat use of the recently described Carpentarian rock-rat, Zyzomys palatalis. The species was previously known from two localities in the Gulf of Carpentaria, and this survey added only one new population to its known range. The species is restricted to monsoon rainforest on scree slopes. In the Gulf region this habitat is very limited and highly fragmented. The only areas where suitable habitat exists are in relatively inaccessible gorges where permanent springs provide enough moisture to maintain the monsoon rainforests. These patches of relict vegetation may be threatened by feral animals and changing fire regimes. Because of the low population size of Z. palatalis and the small size of suitable habitat available, the species is considered to be critically endangered.

First systematic sampling approach to estimating the global population size of the Critically Endangered Blue-throated Macaw Ara glaucogularis

2020 ◽  
pp. 1-19 ◽  
Author(s):  
SEBASTIAN K. HERZOG ◽  
OSWALDO MAILLARD Z. ◽  
TJALLE BOORSMA ◽  
GUSTAVO SÁNCHEZ-ÁVILA ◽  
VÍCTOR HUGO GARCÍA-SOLÍZ ◽  
...  
Keyword(s):  
Population Size ◽  
Critically Endangered ◽  
Population Estimates ◽  
Suitable Habitat ◽  
Landsat 8 ◽  
Entire Area ◽  
Positive Effects ◽  
Population Size Estimates ◽  
Global Population ◽  
Sampling Approach

Summary Reliable population size estimates are imperative for effective conservation and management of globally threatened birds like the ‘Critically Endangered’ Blue-throated Macaw Ara glaucogularis. Endemic to one of South America’s largest grassland floodplains, the Llanos de Moxos in northern Bolivia, the species’ global population size is uncertain. The region’s inaccessibility renders the application of traditional methods for obtaining bird population estimates impracticable or cost prohibitive. We developed a simultaneous, multilocality, double-sampling approach combined with quantitative habitat availability analyses to obtain the first rigorous population size estimate for the Blue-throated Macaw. We established 11 survey areas across its three subpopulations that were visited twice by one team in each subpopulation over a 23-day period in the 2015 dry season and obtained additional count data from two roost sites. We classified suitable habitat (palm forest islands) using Landsat 8 images and CLASlite forest monitoring software. We extrapolated the number of macaws detected (conservative estimate of the total number of macaws [CETN], highest single count [HSC]) per 100 ha of suitable habitat in each survey area to the entire area of suitable habitat in all subpopulations combined, corrected for the species’ range occupancy of 34.3%. The total number of Blue-throated Macaws detected by survey (CETN) and roost site counts was 137. Across all survey areas, the number of macaws per 100 ha of suitable habitat was 4.7 for the first and 4.4 for the second period for CETN and 3.2 and 3.4, respectively, for HSC data. Corresponding global population estimates were 426–455 (CETN) and 312–329 (HSC) individuals. Other recent research and anecdotal data support these estimates. Although it would be premature to propose downlisting the species to ‘Endangered’, our findings indicate that it has a larger population and slightly larger range than previously thought, and that the positive effects of conservation actions are now becoming apparent.

scholarly journals Status and distribution of the endemic Bali starling Leucopsar rothschildi

Oryx ◽  
2000 ◽  
Vol 34 (3) ◽  
pp. 188-197 ◽  
Author(s):  
S. (Bas) van Balen ◽  
I Wayan A. Dirgayusa ◽  
I Made W. Adi Putra ◽  
Herbert H. T. Prins
Keyword(s):  
Population Size ◽  
Small Area ◽  
Small Population ◽  
Critically Endangered ◽  
Suitable Habitat ◽  
Pet Trade ◽  
Monsoon Forest ◽  
Habitat Conversion ◽  
Natural Range ◽  
Precarious Situation

AbstractThe Bali starling Leucopsar rothschildi is a passerine endemic to the dry monsoon forest of the island of Bali, Indonesia. Habitat conversion and excessive capture for the pet trade brought the species to the verge of extinction in the 1980s. The species is critically endangered because of 1) an extremely small population size, 2) restriction to a small area, 3) illegal trapping, and 4) diminishing suitable habitat left within its natural range. An intricate web of factors prevents the Bali starling from emerging from this precarious situation.

Multiscale patterns of habitat use by the Carpentarian rock-rat (Zyzomys palatalis) and the common rock-rat (Z. argurus)

2000 ◽  
Vol 27 (3) ◽  
pp. 319 ◽  
Author(s):  
Colin Trainor ◽  
Alaric Fisher ◽  
John Woinarski ◽  
Sue Churchill
Keyword(s):  
Habitat Use ◽  
Plant Species ◽  
Habitat Requirements ◽  
Suitable Habitat ◽  
Limited Extent ◽  
Environmental Attributes ◽  
Risk Of Extinction ◽  
The Common ◽  
Study Sites ◽  
Monsoon Rainforest

This study examined the habitat requirements of the rare Carpentarian rock-rat (Z. palatalis) and those of the sympatric common rock-rat (Z. argurus). The environmental attributes of 15 study sites, 175 0.1-ha survey quadrats (within 21 sites) and 400 trap cells were summarised by classification and ordination analyses. Whereas Z. argurus was common and widespread throughout much of the environmental variation of sites, quadrats and trap cells, Z. palatalis was recorded from only 4 of 21 sites and 22 of the 175 quadrats. At the three scales examined, Z. palatalis responded strongly to a rockiness gradient, being restricted to the largest, most rugged gorge refuges, and locally was associated with scree piles and rocky slopes vegetated with dry monsoon rainforest and broadleaf woodlands. The richness of all plant species, rainforest plant species, plants bearing dietary items for Zyzomys spp., and shelter were shown to decline with decreasing rockiness and increasing disturbance by fire and cattle. The limited extent of suitable habitat at each of the four known Z. palatalis sites (c. <400 ha each), which is at continual threat from unmanaged fire, in particular, and grazing, will continue to place populations of Z. palatalis at risk of extinction.

scholarly journals Population estimates and habitat use by the Critically Endangered Taita Apalis Apalis fuscigularis in south-eastern Kenya

2010 ◽  
Vol 20 (4) ◽  
pp. 440-455 ◽  
Author(s):  
LUCA BORGHESIO ◽  
DAINA SAMBA ◽  
MWANGI GITHIRU ◽  
LEON BENNUN ◽  
KEN NORRIS
Keyword(s):  
Habitat Use ◽  
Population Size ◽  
Habitat Structure ◽  
Predictive Power ◽  
Total Population ◽  
Distance Sampling ◽  
Critically Endangered ◽  
South Eastern ◽  
Forest Sites ◽  
Global Population

SummaryThe Taita Apalis Apalis fuscigularis (IUCN category: Critically Endangered) is a species endemic to south-eastern Kenya. We assessed population size and habitat use in the three forest sites in which it is known to occur (Ngangao, Chawia and Vuria, totalling 257 ha). The estimate of total population size, derived from distance sampling at 412 sample points, ranged from 310 to 654 individuals, with the northern section of Ngangao fragment having 10-fold higher densities than Chawia (2.47–4.93 versus 0.22–0.41 birds ha−1). Ngangao north alone hosted 50% of the global population of the species. The highly degraded Vuria fragment also had moderately high densities (1.63–3.72 birds ha−1) suggesting that the species tolerates some human disturbance. Taita Apalis prefers vegetation with abundant climbers, but the predictive power of habitat use models was low, suggesting that habitat structure is not a primary cause for the low density of the species in Chawia. Protecting the subpopulation in the northern section of Ngangao is a priority, as is identifying factors responsible of the low abundance in Chawia, because ameliorating conditions in this large fragment could substantially increase the population of Taita Apalis.

scholarly journals Capitoline Dolphins: Residency Patterns and Abundance Estimate of Tursiops truncatus at the Tiber River Estuary (Mediterranean Sea)

Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 275
Author(s):  
Daniela Silvia Pace ◽  
Chiara Di Marco ◽  
Giancarlo Giacomini ◽  
Sara Ferri ◽  
Margherita Silvestri ◽  
...  
Keyword(s):  
Population Size ◽  
Tursiops Truncatus ◽  
Site Fidelity ◽  
Bottlenose Dolphins ◽  
River Estuary ◽  
Suitable Habitat ◽  
Tyrrhenian Sea ◽  
Abundance Estimate ◽  
Photo Identification ◽  
Tiber River

Periodic assessments of population status and trends to detect natural influences and human effects on coastal dolphin are often limited by lack of baseline information. Here, we investigated for the first time the site-fidelity patterns and estimated the population size of bottlenose dolphins (Tursiops truncatus) at the Tiber River estuary (central Mediterranean, Tyrrhenian Sea, Rome, Italy) between 2017 and 2020. We used photo-identification data and site-fidelity metrics to study the tendency of dolphins to remain in, or return to, the study area, and capture–recapture models to estimate the population abundance. In all, 347 unique individuals were identified. The hierarchical cluster analysis highlighted 3 clusters, labeled resident (individuals encountered at least five times, in three different months, over three distinct years; n = 42), part-time (individuals encountered at least on two occasions in a month, in at least two different years; n = 73), and transient (individuals encountered on more than one occasion, in more than 1 month, none of them in more than 1 year; n = 232), each characterized by site-fidelity metrics. Open POPAN modeling estimated a population size of 529 individuals (95% CI: 456–614), showing that the Capitoline (Roman) coastal area and nearby regions surrounding the Tiber River estuary represent an important, suitable habitat for bottlenose dolphins, despite their proximity to one of the major urban centers in the world (the city of Rome). Given the high number of individuals in the area and the presence of resident individuals with strong site fidelity, we suggest that conservation plans should not be focused only close to the Tiber River mouths but extended to cover a broader scale of area.

Assisted colonisation trial of the eastern barred bandicoot (Perameles gunnii) to a fox-free island

2017 ◽  
Vol 44 (7) ◽  
pp. 484 ◽  
Author(s):  
Rebecca Groenewegen ◽  
Dan Harley ◽  
Richard Hill ◽  
Graeme Coulson
Keyword(s):  
Habitat Use ◽  
Body Condition ◽  
Red Fox ◽  
Suitable Habitat ◽  
Viable Option ◽  
Predator Exclusion ◽  
In The Wild ◽  
Radio Transmitters ◽  
Release Group ◽  
Small Sites

Context Assisted colonisation has the potential to protect species from intractable threats within their historical ranges. The Australian mainland subspecies of the eastern barred bandicoot (Perameles gunnii) is extinct in the wild, with surviving populations restricted to small sites protected by predator–barrier fences. PVA modelling shows that a self-sustaining bandicoot population would require an area free of the introduced red fox (Vulpes vulpes) of at least 2500ha. French Island is outside the historic range of the species, but is fox-free and contains around 9000ha of potentially suitable habitat. Aims This study will assess the suitability of French Island as a potential site for a self-sustaining eastern barred bandicoot population by conducting a 1-year assisted colonisation trial to assess habitat use, body condition and survival. Methods Between July and September 2012, 18 adult bandicoots were released. We radio-tracked bandicoots using intraperitoneal radio-transmitters for up to 122 days and trapped fortnightly. Key results The release group met the three measures of success: (1) appropriate habitat use; (2) recovery of post-release bodyweight; and (3) founder survival exceeding 100 days. Habitat use and body condition throughout the trial reflected that of mainland populations, and seven bandicoots survived longer than 100 days. Mortality was greatest in the first month, with veterinary investigations confirming two deaths due to cat predation, two deaths from toxoplasmosis and one unknown cause of death. Bandicoots that survived longer than 100 days occupied higher, drier ground than those that did not. Toxoplasmosis cases were associated with lower topographic position on the site. Conclusions Our results suggest that French Island provides suitable habitat for the establishment of a population of eastern barred bandicoots. On French Island, toxoplasmosis was identified as an important source of mortality in addition to cat predation, and warrants further investigation. Implications Given the costs and challenges of predator control and the maintenance of predator exclusion fences, assisted colonisation to one or more fox-free islands remains the most viable option to establish self-sustaining bandicoot populations. Our results highlight the value in conducting trial releases ahead of major translocations.

scholarly journals Distribution and habitat associations of the Critically Endangered frog Walkerana phrynoderma (Anura: Ranixalidae), with an assessment of potential threats, abundance, and morphology

2018 ◽  
Vol 17 (1) ◽  
pp. 21
Author(s):  
Arun Kanagavel ◽  
Sethu Parvathy ◽  
Abhiijth P. Chundakatil ◽  
Neelesh Dahanukar ◽  
Benjamin Tapley
Keyword(s):  
Western Ghats ◽  
Tamil Nadu ◽  
Habitat Associations ◽  
Critically Endangered ◽  
Suitable Habitat ◽  
Time Activity ◽  
Western Ghats Of India ◽  
Pesticide Runoff ◽  
The Impact ◽  
The Western Ghats

Distribution and habitat associations of the Critically Endangered frog Walkerana phrynoderma (Anura: Ranixalidae), with an assessment of potential threats, abundance, and morphology. Little is known about Walkerana phrynoderma, a frog endemic to the Anamalai Hills of the Western Ghats of India. Baseline information (i.e., distribution, threats, habitat characteristics, activity patterns, and relative abundance) is provided for this species, with the aim of improving our understanding of the status of the species in the wild. Visual-encounter, transect, and time-activity budget surveys were conducted in and around the Anamalai Hills of the Western Ghats. The frog skin was swabbed to determine the presence/absence of Batrachochytrium dendrobatidis, and habitat and environmental characteristics were recorded at sites where W. phrynoderma was found. These data were compared with those of sites apparently lacking this species that had suitable habitat. Walkerana phrynoderma is restricted to evergreen forests between 1300 and 1700 m a.s.l. in the Anamalai Tiger Reserve and at Munnar; thus, its range was extended from the state of Tamil Nadu to the adjoining state of Kerala. Pesticide runoff and human disturbance are the most severe threats to the species; B. dendrobatidis was not detected. This nocturnal anuran prefers forest edges and is associated with well-shaded forest foors in cool areas near freshwater streams. Walkerana phrynoderma is rarely encountered whereas its congener, W. leptodactyla, is more common. The impact of anthropogenic disturbances, especially waste disposal and development of tourism infrastructure, should be evaluated. The land that is owned by the Forest Department peripheral to the protected areas could be designated as eco-sensitive sites to prevent changes in land use that could have an adverse effect on W. phrynoderma.

Global population size of a critically endangered lemur, Perrier's sifaka

2007 ◽  
Vol 10 (2) ◽  
pp. 254-262 ◽  
Author(s):  
M. A. Banks ◽  
E. R. Ellis ◽  
Antonio ◽  
P. C. Wright
Keyword(s):  
Population Size ◽  
Critically Endangered ◽  
Global Population
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