scholarly journals Current status of the threatened Dupont's lark Chersophilus duponti in Spain: overestimation, decline, and extinction of local populations

Oryx ◽  
2005 ◽  
Vol 39 (1) ◽  
pp. 90-94 ◽  
Author(s):  
José L. Tella ◽  
Matthias Vögeli ◽  
David Serrano ◽  
Martina Carrete
Keyword(s):  
Habitat Degradation ◽  
Iucn Red List ◽  
European Population ◽  
Current Status ◽  
Isolated Populations ◽  
Local Populations ◽  
Population Sizes ◽  
Line Transects ◽  
Dupont’S Lark

The European population of Dupont's lark Chersophilus duponti, restricted to Spanish steppe, was estimated to be 13,000 pairs in c. 50 populations in 1988. There is, however, recent evidence that this number was overestimated because of the previous use of line transects for estimating population sizes. In 2002–2004 we surveyed 34 previously known local populations in patches of variable size across half of its Spanish distribution. We found 13 (38%) local populations to be extinct, and a total of only 283–339 territories in 17 of the extant populations, seven of which held <5 territories. This census contrasts dramatically with the estimate of c. 3,000 pairs in the same populations in the 1980s. We estimate that the present Spanish population is c. 1,300 pairs. The discrepancy between this and earlier estimates is partly but not entirely due to previous overestimations. Habitat loss due to ploughing, and possibly habitat degradation and the resulting stochastic extinction of small and isolated populations, have contributed to the species' decline. Urgent research is needed to design and manage an adequate network of steppe patches that will ensure the long-term existence of this species. We recommend that Dupont's lark be categorized on the IUCN Red List as Endangered, both globally and nationally within Spain.

scholarly journals Dramatic decline of the Vulnerable Reeves's pheasant Syrmaticus reevesii, endemic to central China

Oryx ◽  
2014 ◽  
Vol 49 (3) ◽  
pp. 529-534 ◽  
Author(s):  
Chunfa Zhou ◽  
Jiliang Xu ◽  
Zhengwang Zhang
Keyword(s):  
Protected Areas ◽  
Population Decline ◽  
Iucn Red List ◽  
Central China ◽  
Current Status ◽  
Term Survival ◽  
Field Surveys ◽  
Dramatic Decline ◽  
Syrmaticus Reevesii

AbstractThe current status and distribution of the Vulnerable Reeves's pheasant Syrmaticus reevesii, endemic to central China, is poorly known. To obtain updated information on its status we selected 89 candidate sites in six provinces and one municipality in central China and conducted interviews and field surveys from April 2011 to April 2012. Interviews demonstrated the pheasant has disappeared from 46% of the surveyed sites. Our results also revealed a population decline at 46 sites, including protected areas, although population densities in protected areas were higher than those in non-protected areas. Eighty-three, 26 and 20% of the surveyed sites had evidence of poaching, habitat loss and use of poison, respectively, which were the three major threats to this species. To ensure the long-term survival of Reeves's pheasant in China, protection and management need to be enforced in both protected and non-protected areas. We recommend that this species should be upgraded to a national first-level protected species in China and recategorized as Endangered on the IUCN Red List.

Effect of landscape variables on the long-term decline of Great Argus in the rainforest of Southern Thailand

2017 ◽  
Vol 27 (2) ◽  
pp. 282-293 ◽  
Author(s):  
THANEE DAWRUENG ◽  
DUSIT NGOPRASERT ◽  
GEORGE A. GALE ◽  
STEPHEN BROWNE ◽  
TOMMASO SAVINI
Keyword(s):  
Human Disturbance ◽  
Habitat Degradation ◽  
Forest Edge ◽  
Evergreen Forest ◽  
Negative Effects ◽  
Point Counts ◽  
Southern Thailand ◽  
Line Transects ◽  
Long Term Studies

SummaryIn Thailand, as for most of South-East Asia, large vertebrates are declining rapidly due to habitat degradation and increasing hunting pressure. Once relatively common in the evergreen forest of Southern Thailand, the Great ArgusArgusianus argusis currently limited to a few populations, whose status is currently unknown. In this study we investigated changes in Great Argus abundance over the past 13 years in Hala-Bala Wildlife Sanctuary. Our aim was to estimate and compare the abundance and density of this species from an earlier two-year survey in 2001–2002 and ours in 2014, and to assess the effect of landscape change on its status of the species. We conducted surveys from March to August 2014 during the breeding season. We placed point counts that overlapped the line transects from the 2001–2002 survey. The results indicated a decline of > 35% in mean abundance from 2001 to 2014. In addition, male abundance has shifted and is now positively related to distance from the forest edge. High levels of human disturbance close to the forest edge may have resulted in the birds moving to the core of the forest, suggesting a need to increase protection and management of forest edge areas. In common with other studies of large vertebrates, our results confirm the importance of long-term studies to highlight the negative effects of human disturbance.

scholarly journals Current status and conservation strategies for Isoetes in China: a case study for the conservation of threatened aquatic plants

Oryx ◽  
2005 ◽  
Vol 39 (3) ◽  
pp. 335-338 ◽  
Author(s):  
Xing Liu ◽  
Jing-Yuan Wang ◽  
Qing-Feng Wang
Keyword(s):  
Habitat Degradation ◽  
Conservation Status ◽  
Mainland China ◽  
Iucn Red List ◽  
Habitat Characteristics ◽  
Wild Plants ◽  
Current Status ◽  
Conservation Strategies ◽  
The Government

There are four known species of Isoetes (Family Isoetaceae) from China: I. hypsophila, I. sinensis and I. yunguiensis on the mainland, and I. taiwanensis on Taiwan. In a 4-year study we documented the distribution and habitat characteristics of all four species and evaluated their conservation status using IUCN criteria. All four species are facing a high risk of extinction and should be categorized as Critically Endangered on the IUCN Red List. Habitat degradation and loss, water pollution and eutrophication, competitive exclusion, and human disturbance are the main factors causing the decline and extirpation of Isoetes. Only I. taiwanensis is protected in situ in Yangmingshan National Park on Taiwan. None of the species or habitats of Isoetes on mainland China are presently protected, although all species have been designated by the government as State Key Protected Wild Plants. Our results suggest that conservation strategies should be implemented urgently, particularly on the mainland.

scholarly journals Current population status of the endangered Hog Deer Axis porcinus (Mammalia: Cetartiodactyla: Cervidae) in the Terai grasslands: a study following political unrest in Manas National Park, India ­

2019 ◽  
Vol 11 (13) ◽  
pp. 14655-14662
Author(s):  
Alolika Sinha ◽  
Bibhuti Prasad Lahkar ◽  
Syed Ainul Hussain
Keyword(s):  
National Park ◽  
Invasive Plant ◽  
Habitat Degradation ◽  
Distance Sampling ◽  
Current Status ◽  
Population Declines ◽  
Population Status ◽  
Illegal Hunting ◽  
Current Population ◽  
Line Transects

The Endangered Hog Deer Axis porcinus has experienced drastic population declines throughout its geographical range.  There is limited knowledge of its current population status, particularly from northeastern India.  In this study the population density of Hog Deer was assessed in Manas National Park, which was a deer stronghold prior to the armed conflict that lasted for almost two decades, resulting in depressed deer populations.  With the cessation of conflict, efforts were invested by both government and conservation organisations for the recovery and conservation of charismatic fauna in the park.  Studies on Hog Deer populations, however, were lacking and thus reliable information on current status is unavailable.  Current population status and threats faced by Hog Deer were assessed to aid informed conservation decisions.  Distance sampling techniques (line transects) were applied in the grassland habitat during the dry season of two consecutive years.  The estimated Hog Deer density was 18.22±3.32 km-2.  The potential threats to Hog Deer identified in Manas include habitat loss, habitat degradation due to spread of invasive plant species, illegal hunting, and other anthropogenic disturbances.  Our study suggests that the Hog Deer population, though reviving, needs immediate conservation attention.

scholarly journals Trends in extinction and persistence of diurnal primates in the fragmented lowland rainforests of the Upper Brahmaputra Valley, north-eastern India

Oryx ◽  
2012 ◽  
Vol 46 (2) ◽  
pp. 308-311 ◽  
Author(s):  
Narayan Sharma ◽  
M. D. Madhusudan ◽  
Prabal Sarkar ◽  
Mayur Bawri ◽  
Anindya Sinha
Keyword(s):  
Census Data ◽  
Habitat Degradation ◽  
Current Status ◽  
Human Populations ◽  
Forest Fragments ◽  
Brahmaputra Valley ◽  
North Eastern ◽  
Key Informant ◽  
Indian State

AbstractThe historical deforestation of the Upper Brahmaputra Valley in the Indian state of Assam has resulted in the transformation of its once-contiguous lowland rainforests into many isolated forest fragments that are still rich in species, including primates. We report the recent history and current status of six diurnal primates in one large (2,098 ha) and three small (<500 ha) fragments of the Upper Brahmaputra Valley. We censused primates in the small fragments during 2002, 2005, 2009, in the large fragment in 2008, and used other published census data to derive population trends. We also used key informant surveys to obtain historical occurrence data for these populations. Our analyses reveal the recent extinction of some populations and the simultaneous long-term persistence of others in these fragments over 16 years. Most populations appeared to have declined in the small fragments but primate abundance has increased significantly in the largest fragment over the last decade. Addressing the biomass needs of the local human populations, which appears to drive habitat degradation, and better protection of these forests, will be crucial in ensuring the future survival of this diverse and unique primate assemblage in the last rainforest fragments of the human-dominated Upper Brahmaputra Valley.

scholarly journals Population densities and conservation status of Norfolk Island forest birds

2012 ◽  
Vol 23 (3) ◽  
pp. 271-282 ◽  
Author(s):  
GUY DUTSON
Keyword(s):  
National Park ◽  
Conservation Status ◽  
Bird Species ◽  
Iucn Red List ◽  
Small Population ◽  
Population Densities ◽  
Point Counts ◽  
Norfolk Island ◽  
Population Sizes ◽  
Line Transects

SummaryThree weeks of intensive surveys in Norfolk Island National Park in 2009 failed to find White-chested White-eye Zosterops albogularis and it was calculated that there was a less than 17% probability that a population of 10 birds had been overlooked. The last multi-observer record of this species was in 1978, and it is recommended that the species’ IUCN Red List status of “Critically Endangered” is tagged as “Possibly Extinct”. During these surveys, the population densities of seven bird species were calculated from 352 independent point counts. Causes of imprecision and bias were investigated, suggesting a small underestimation. Other species were recorded too infrequently, or their distributions were too biased, for analysis. The population densities of the extant endemic taxa were relatively high and suggest no current declines, and the population estimates were consistent with previous studies. This study recommends monitoring most species by point counts, or line transects if resources are limited, supplemented with specific monitoring of Tasman (Norfolk Island) Parakeet Cyanoramphus cookii, Pacific Robin Petroica multicolor, Southern Boobook Ninox novaeseelandiae and seabirds. Ongoing monitoring of these birds is needed to help inform management of the National Park and the island in general, given their small population sizes and their likely susceptibility to rat and cat predation, competition from alien species and drought.

scholarly journals Long Term Interactions of Native and Invasive Species in a Marine Protected Area Suggest Complex Cascading Effects Challenging Conservation Outcomes

Diversity ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 71
Author(s):  
Charalampos Dimitriadis ◽  
Ivoni Fournari-Konstantinidou ◽  
Laurent Sourbès ◽  
Drosos Koutsoubas ◽  
Stelios Katsanevakis
Keyword(s):  
Invasive Species ◽  
Native Species ◽  
High Performance ◽  
Marine Protected Area ◽  
Habitat Degradation ◽  
Population Increase ◽  
Rocky Reef ◽  
Cascading Effects ◽  
High Level

Understanding the interactions among invasive species, native species and marine protected areas (MPAs), and the long-term regime shifts in MPAs is receiving increased attention, since biological invasions can alter the structure and functioning of the protected ecosystems and challenge conservation efforts. Here we found evidence of marked modifications in the rocky reef associated biota in a Mediterranean MPA from 2009 to 2019 through visual census surveys, due to the presence of invasive species altering the structure of the ecosystem and triggering complex cascading effects on the long term. Low levels of the populations of native high-level predators were accompanied by the population increase and high performance of both native and invasive fish herbivores. Subsequently the overgrazing and habitat degradation resulted in cascading effects towards the diminishing of the native and invasive invertebrate grazers and omnivorous benthic species. Our study represents a good showcase of how invasive species can coexist or exclude native biota and at the same time regulate or out-compete other established invaders and native species.

scholarly journals Global extinction risk for seahorses, pipefishes and their near relatives (Syngnathiformes)

Oryx ◽  
2021 ◽  
pp. 1-10
Author(s):  
Riley A. Pollom ◽  
Gina M. Ralph ◽  
Caroline M. Pollock ◽  
Amanda C.J. Vincent
Keyword(s):  
Threatened Species ◽  
Habitat Degradation ◽  
Extinction Risk ◽  
Conservation Status ◽  
Field Research ◽  
Selective Extraction ◽  
Iucn Red List ◽  
Point Estimate ◽  
Conservation Action ◽  
Data Deficient

Abstract Few marine taxa have been comprehensively assessed for their conservation status, despite heavy pressures from fishing, habitat degradation and climate change. Here we report on the first global assessment of extinction risk for 300 species of syngnathiform fishes known as of 2017, using the IUCN Red List criteria. This order of bony teleosts is dominated by seahorses, pipefishes and seadragons (family Syngnathidae). It also includes trumpetfishes (Aulostomidae), shrimpfishes (Centriscidae), cornetfishes (Fistulariidae) and ghost pipefishes (Solenostomidae). At least 6% are threatened, but data suggest a mid-point estimate of 7.9% and an upper bound of 38%. Most of the threatened species are seahorses (Hippocampus spp.: 14/42 species, with an additional 17 that are Data Deficient) or freshwater pipefishes of the genus Microphis (2/18 species, with seven additional that are Data Deficient). Two species are Near Threatened. Nearly one-third of syngnathiformes (97 species) are Data Deficient and could potentially be threatened, requiring further field research and evaluation. Most species (61%) were, however, evaluated as Least Concern. Primary threats to syngnathids are (1) overexploitation, primarily by non-selective fisheries, for which most assessments were determined by criterion A (Hippocampus) and/or (2) habitat loss and degradation, for which assessments were determined by criterion B (Microphis and some Hippocampus). Threatened species occurred in most regions but more are found in East and South-east Asia and in South African estuaries. Vital conservation action for syngnathids, including constraining fisheries, particularly non-selective extraction, and habitat protection and rehabilitation, will benefit many other aquatic species.

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