scholarly journals Cryptic diversity and ranavirus infection of a critically endangered Neotropical frog before and after population collapse

2019 ◽  
Vol 22 (5) ◽  
pp. 515-524 ◽  
Author(s):  
R. Puschendorf ◽  
M. Wallace ◽  
M. M. Chavarría ◽  
A. J. Crawford ◽  
F. Wynne ◽  
...  
Keyword(s):  
Critically Endangered ◽  
Cryptic Diversity ◽  
Population Collapse ◽  
Before And After

scholarly journals Hybridization following population collapse in a critically endangered antelope

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Pedro Vaz Pinto ◽  
Pedro Beja ◽  
Nuno Ferrand ◽  
Raquel Godinho
Keyword(s):  
Critically Endangered ◽  
Population Collapse

scholarly journals Integrated conservation of the Whenua Hou Diving Petrel

2021 ◽  
Author(s):  
◽  
Johannes Fischer
Keyword(s):  
Population Growth ◽  
Nest Survival ◽  
Critically Endangered ◽  
Conservation Strategy ◽  
Conservation Strategies ◽  
Commercial Fishing ◽  
Breeding Distribution ◽  
Before And After ◽  
The Impact ◽  
Diving Petrel

<p>Seabirds are one of the most threatened taxa on the planet. These species are also considered ecosystem engineers. Therefore, seabirds are of particular conservation interest. One of the most threatened seabirds is the critically endangered Whenua Hou Diving Petrel (Pelecanoides whenuahouensis; WHDP). The WHDP is restricted to a minute (0.018 km2) breeding colony on a single island — Whenua Hou (Codfish Island), Aotearoa (New Zealand). The WHDP population was estimated at 150 adults in 2005. The WHDP is threatened by storms and storm surges, which erode its breeding habitat (fragile foredunes), and potentially by competition for burrows with congenerics.  I aimed to inform suitable conservation strategies for the WHDP. I first quantified the efficacy of past conservation actions (eradications of invasive predators). I compiled burrow counts across four decades to estimate and compare population growth before and after predator eradications. I then investigated offshore threats using tracking data to quantify WHDP offshore distribution, behaviour, and overlap with commercial fishing efforts. Subsequently, I estimated the potential impact and success of WHDP translocations. Specifically, I combined capture-recapture, nest-monitoring, and count data in an integrated population model (IPM) to predict the impact of harvesting chicks for translocations on the source population and to project the establishment of a second population. I then informed future translocation protocols using nest-monitoring data to quantify nest survival and breeding biology. Finally, I tested if WHDP presence had a positive influence on unrelated species groups. I counted two skink species at sites with and without burrows and used occupancy modelling to quantify the influence WHDP burrows had on skink occurrence.  Estimates of population growth before and after predator eradications illustrated that WHDP population growth remained comparatively low and unaffected by this conservation strategy. Therefore, additional interventions are required. WHDP tracking revealed that the non-breeding distribution did not overlap with commercial fishing efforts. However, considerable fishing efforts were present within the breeding distribution. Despite these findings, onshore threats remain present and conservation strategies aimed at addressing terrestrial threats may be more feasible. Results from my IPM showed that translocations could successfully establish a second WHDP population without impacting the source excessively, provided translocation cohorts remain small and translocations are repeated over long time periods (5-10 years). Nest survival was not clearly influenced by interannual variation, distance to sea, and intra- or interspecific competition. Furthermore, I informed future translocation protocols by identifying the preferred harvest window, measurements of ideal translocation candidates, and feeding regimes. Occurrence of one skink species was 114% higher at sites with burrows than at sites without, suggesting that WHDP presence benefits unrelated species.  The information provided in this thesis facilitates the identification of future management strategies for this critically endangered species. However, future conservation management of the WHDP should be based on structured decision-making frameworks that apply iterative adaptive management loops and must acknowledge the unique position of tangata whenua (people of the land). This approach could address the consequences and trade-offs of each alternative, account for uncertainty, facilitate the decolonisation of conservation biology, and would ultimately result in the best potential outcome of the target species in a truly integrated fashion.</p>

scholarly journals Genomic effects of population collapse in a critically endangered ironwood tree Ostrya rehderiana

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Yongzhi Yang ◽  
Tao Ma ◽  
Zefu Wang ◽  
Zhiqiang Lu ◽  
Ying Li ◽  
...  
Keyword(s):  
Critically Endangered ◽  
Population Collapse ◽  
Genomic Effects

scholarly journals Critically Endangered totoaba Totoaba macdonaldi: signs of recovery and potential threats after a population collapse

2015 ◽  
Vol 29 (1) ◽  
pp. 1-11 ◽  
Author(s):  
F Valenzuela-Quiñonez ◽  
F Arreguín-Sánchez ◽  
S Salas-Márquez ◽  
FJ García-De León ◽  
JC Garza ◽  
...  
Keyword(s):  
Critically Endangered ◽  
Population Collapse ◽  
Totoaba Macdonaldi

scholarly journals Wildlife in the line of fire: evaluating the stress physiology of a critically endangered Australian marsupial after bushfire

2016 ◽  
Vol 64 (6) ◽  
pp. 385 ◽  
Author(s):  
Stephanie Hing ◽  
Krista L. Jones ◽  
Christine Rafferty ◽  
R. C. Andrew Thompson ◽  
Edward J. Narayan ◽  
...  
Keyword(s):  
Body Condition ◽  
Population Level ◽  
Parasite Load ◽  
Critically Endangered ◽  
Stress Physiology ◽  
Sample Collection ◽  
Bettongia Penicillata ◽  
Before And After ◽  
The Impact ◽  
Australian Marsupial

Australian native fauna are thought to be well adapted to fire-prone landscapes, but bushfires may still pose considerable challenges or stressors to wildlife. We investigated the impact of bushfire on the stress physiology of the woylie (brush-tailed bettong, Bettongia penicillata) a critically endangered Australian marsupial, and assessed whether fitness indices (body condition and parasite load) influenced stress physiology before and after the fire. We hypothesised that there would be a significant change in stress physiology indicators (in the form of faecal cortisol metabolites, FCM) following the fire, compared with the months previous. We trapped woylies (n = 19) at Whiteman Park Reserve in Perth, Western Australia, two days after a major bushfire and measured FCM concentration by enzyme immunoassay. Population-level comparisons of FCM were made between these samples and those collected in previous months (n = 58). While mean FCM varied by month of sample collection, it was not higher after the fire. We suggest that woylies may be able to maintain homeostasis through change (allostasis), at least in the period immediately after the fire. This is supported by our finding that FCM did not relate significantly to body condition or parasite load. Our results potentially highlight the physiological and behavioural adaptations of woylies to fire, which could be further explored in future studies.

scholarly journals Genetic Diversity Despite Population Collapse in a Critically Endangered Marine Fish: The Smalltooth Sawfish (Pristis pectinata)

2011 ◽  
Vol 102 (6) ◽  
pp. 643-652 ◽  
Author(s):  
Demian D. Chapman ◽  
Colin A. Simpfendorfer ◽  
Tonya R. Wiley ◽  
Gregg R. Poulakis ◽  
Caitlin Curtis ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Marine Fish ◽  
Critically Endangered ◽  
Population Collapse ◽  
Pristis Pectinata

scholarly journals Range‐wide breeding habitat use of the critically endangered Yellow‐breasted Bunting Emberiza aureola after population collapse

2021 ◽  
Author(s):  
Ilka Beermann ◽  
Alexander Thomas ◽  
Yury Anisimov ◽  
Marc Bastardot ◽  
Nyambayar Batbayar ◽  
...  
Keyword(s):  
Habitat Use ◽  
Breeding Habitat ◽  
Critically Endangered ◽  
Population Collapse

scholarly journals Integrated conservation of the Whenua Hou Diving Petrel

2021 ◽  
Author(s):  
◽  
Johannes Fischer
Keyword(s):  
Population Growth ◽  
Nest Survival ◽  
Critically Endangered ◽  
Conservation Strategy ◽  
Conservation Strategies ◽  
Commercial Fishing ◽  
Breeding Distribution ◽  
Before And After ◽  
The Impact ◽  
Diving Petrel

<p>Seabirds are one of the most threatened taxa on the planet. These species are also considered ecosystem engineers. Therefore, seabirds are of particular conservation interest. One of the most threatened seabirds is the critically endangered Whenua Hou Diving Petrel (Pelecanoides whenuahouensis; WHDP). The WHDP is restricted to a minute (0.018 km2) breeding colony on a single island — Whenua Hou (Codfish Island), Aotearoa (New Zealand). The WHDP population was estimated at 150 adults in 2005. The WHDP is threatened by storms and storm surges, which erode its breeding habitat (fragile foredunes), and potentially by competition for burrows with congenerics.  I aimed to inform suitable conservation strategies for the WHDP. I first quantified the efficacy of past conservation actions (eradications of invasive predators). I compiled burrow counts across four decades to estimate and compare population growth before and after predator eradications. I then investigated offshore threats using tracking data to quantify WHDP offshore distribution, behaviour, and overlap with commercial fishing efforts. Subsequently, I estimated the potential impact and success of WHDP translocations. Specifically, I combined capture-recapture, nest-monitoring, and count data in an integrated population model (IPM) to predict the impact of harvesting chicks for translocations on the source population and to project the establishment of a second population. I then informed future translocation protocols using nest-monitoring data to quantify nest survival and breeding biology. Finally, I tested if WHDP presence had a positive influence on unrelated species groups. I counted two skink species at sites with and without burrows and used occupancy modelling to quantify the influence WHDP burrows had on skink occurrence.  Estimates of population growth before and after predator eradications illustrated that WHDP population growth remained comparatively low and unaffected by this conservation strategy. Therefore, additional interventions are required. WHDP tracking revealed that the non-breeding distribution did not overlap with commercial fishing efforts. However, considerable fishing efforts were present within the breeding distribution. Despite these findings, onshore threats remain present and conservation strategies aimed at addressing terrestrial threats may be more feasible. Results from my IPM showed that translocations could successfully establish a second WHDP population without impacting the source excessively, provided translocation cohorts remain small and translocations are repeated over long time periods (5-10 years). Nest survival was not clearly influenced by interannual variation, distance to sea, and intra- or interspecific competition. Furthermore, I informed future translocation protocols by identifying the preferred harvest window, measurements of ideal translocation candidates, and feeding regimes. Occurrence of one skink species was 114% higher at sites with burrows than at sites without, suggesting that WHDP presence benefits unrelated species.  The information provided in this thesis facilitates the identification of future management strategies for this critically endangered species. However, future conservation management of the WHDP should be based on structured decision-making frameworks that apply iterative adaptive management loops and must acknowledge the unique position of tangata whenua (people of the land). This approach could address the consequences and trade-offs of each alternative, account for uncertainty, facilitate the decolonisation of conservation biology, and would ultimately result in the best potential outcome of the target species in a truly integrated fashion.</p>

scholarly journals Partial recovery of Critically Endangered Gyps vulture populations in Nepal

2019 ◽  
Vol 30 (1) ◽  
pp. 87-102 ◽  
Author(s):  
TOBY H. GALLIGAN ◽  
KRISHNA P. BHUSAL ◽  
KHADANANDA PAUDEL ◽  
DEVENDRA CHAPAGAIN ◽  
ANKIT B. JOSHI ◽  
...  
Keyword(s):  
Free Food ◽  
Critically Endangered ◽  
Rapid Decline ◽  
Partial Recovery ◽  
Safe Alternative ◽  
Closed Population ◽  
Piecewise Regression ◽  
Before And After ◽  
Vulture Conservation ◽  
Gyps Bengalensis

SummaryPopulations of Critically Endangered White-rumped Gyps bengalensis and Slender-billed G. tenuirostris Vultures in Nepal declined rapidly during the 2000s, almost certainly because of the effects of the use in livestock of the non-steroidal anti-inflammatory drug diclofenac, which is nephrotoxic to Gyps vultures. In 2006, veterinary use of diclofenac was banned in Nepal and this was followed by the gradual implementation, over most of the geographical range of the two vulture species in Nepal, of a Vulture Safe Zone (VSZ) programme to advocate vulture conservation, raise awareness about diclofenac, provide vultures with NSAID-free food and encourage the veterinary use in livestock of a vulture-safe alternative NSAID (meloxicam). We report the results of long-term monitoring of vulture populations in Nepal before and after this programme was implemented, by means of road transects. Piecewise regression analysis of the count data indicated that a rapid decline of the White-rumped Vulture population from 2002 up to about 2013 gave way to a partial recovery between about 2013 and 2018. More limited data for the Slender-billed Vulture indicated that a rapid decline also gave way to partial recovery from about 2012 onwards. The rates at which populations were increasing in the 2010s exceeded the upper end of the range of increase rates expected in a closed population under optimal conditions. The possibility that immigration from India is contributing to the changes cannot be excluded. We present evidence from open and undercover pharmacy surveys that the VSZ programme had apparently become effective in reducing the availability of diclofenac in a large part of the range of these species in Nepal by about 2011. Hence, community-based advocacy and awareness-raising actions, and possibly also provisioning of safe food, may have made an important contribution to vulture conservation by augmenting the effects of changes in the regulation of toxic veterinary drugs.

Deformation Replication

1970 ◽  
Vol 28 ◽  
pp. 280-281
Author(s):  
J. Temple Black
Keyword(s):  
Cutting Speed ◽  
Machining Process ◽  
Depth Of Cut ◽  
Rake Face ◽  
Orthogonal Machining ◽  
Aluminum Chips ◽  
Before And After ◽  
Materials Used ◽  
Glass Knife ◽  
Very High

Tool materials used in ultramicrotomy are glass, developed by Latta and Hartmann (1) and diamond, introduced by Fernandez-Moran (2). While diamonds produce more good sections per knife edge than glass, they are expensive; require careful mounting and handling; and are time consuming to clean before and after usage, purchase from vendors (3-6 months waiting time), and regrind. Glass offers an easily accessible, inexpensive material ($0.04 per knife) with very high compressive strength (3) that can be employed in microtomy of metals (4) as well as biological materials. When the orthogonal machining process is being studied, glass offers additional advantages. Sections of metal or plastic can be dried down on the rake face, coated with Au-Pd, and examined directly in the SEM with no additional handling (5). Figure 1 shows aluminum chips microtomed with a 75° glass knife at a cutting speed of 1 mm/sec with a depth of cut of 1000 Å lying on the rake face of the knife.

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