scholarly journals Impact of predation by the black rat, rattus rattus, on the breeding success of cory’s shearwater, Calonectris diomedea, on Linosa island (Sicily, Italy)

2012 ◽  
Vol 82 (1/2) ◽  
Author(s):  
Giuseppe Rannisi ◽  
Loredana Murabito ◽  
Marco Gustin ◽  
Bruno Massa
2011 ◽  
Vol 21 (3) ◽  
pp. 342-352 ◽  
Author(s):  
MARTA LOPEZ-DARIAS ◽  
JAVIER LUZARDO ◽  
RAFAEL MARTÍNEZ ◽  
DANIEL GONZÁLEZ ◽  
EDUARDO A. GARCÍA ◽  
...  

SummaryNegative effects of poaching on seabird populations are not usually evaluated quantitatively when assessing seabird colony conservation status, nor are they generally considered a major concern. We demonstrate that poaching is still intense in the Canary Islands, and has negative consequences for the conservation of seabird colonies. We quantified the effects of poaching of Cory’s Shearwater fledglings on breeding success on different islands in the Canaries, comparing colonies that suffer from intense, medium, or no poaching. Poaching reduced the breeding success of affected colonies to almost a third, potentially causing the future extinction of the colony. Only colonies with intense wardening campaigns reached high values of reproductive success, showing that government surveillance in conjunction with volunteers from different NGOs is a very effective approach in reducing poaching. A population sensitivity analysis was also conducted to provide data on the factors that most affect the performance of the model. Although population growth and mean final population size varied with increases and decreases in mortality and carrying capacity, only harvesting resulted in a probability of 100% of extinction in 20–40 years. To promote seabird conservation in regions such as the Canary Islands, a core archipelago for seabird species in the Atlantic, poaching control should be elevated by society to a level of urgency, requiring dedicated funding and mobilisation of experts and volunteers to adequately address it through education, prevention and enforcement.


2019 ◽  
Vol 25 (1) ◽  
Author(s):  
ASHOK KUMAR ◽  
ALPANA PARMAR ◽  
ANAND KUMAR BAJPEYEE

Young female Black rat (Rattus rattus), were administered monthly long acting steroid contraceptive to induce hypertriglyceridemia. It was observed that by 3 weeks of the second injection of estrogen containing mixed type of contraceptive, female rats developed consistent and frank hyperglyceridemia . TG in the treated rats was 195.8 ± 7.44 mg /100 ml as compared to 91.5 ± 6.27 mg/100ml in plasma of the control group.


The Auk ◽  
2000 ◽  
Vol 117 (3) ◽  
pp. 651-662 ◽  
Author(s):  
Corinne Rabouam ◽  
Vincent Bretagnolle ◽  
Yves Bigot ◽  
Georges Periquet

Abstract We used DNA fingerprinting to assess genetic structure of populations in Cory's Shearwater (Calonectris diomedea). We analyzed mates and parent-offspring relationships, as well as the amount and distribution of genetic variation within and among populations, from the level of subcolony to subspecies. We found no evidence of extrapair fertilization, confirming that the genetic breeding system matches the social system that has been observed in the species. Mates were closely related, and the level of genetic relatedness within populations was within the range usually found in inbred populations. In contrast to previous studies based on allozymes and mtDNA polymorphism, DNA fingerprinting using microsatellites revealed consistent levels of genetic differentiation among populations. However, analyzing the two subspecies separately revealed that the pattern of genetic variation among populations did not support the model of isolation by distance. Natal dispersal, as well as historic and/or demographic events, probably contributed to shape the genetic structure of populations in the species.


The Holocene ◽  
2011 ◽  
Vol 22 (7) ◽  
pp. 801-808 ◽  
Author(s):  
Juan Carlos Rando ◽  
Josep Antoni Alcover ◽  
Jacques Michaux ◽  
Rainer Hutterer ◽  
Juan Francisco Navarro

The Lava mouse ( Malpaisomys insularis), and the Canarian shrew ( Crocidura canariensis) are endemic of the Eastern Canary Islands and islets. The former is extinct while Canarian shrew survives in the two main islands and two islets. In order to provide insights regarding causes and processes contributing to the extinction of these endemic mammals: (i) we established last occurrence dates for Lava mouse, and first records for two exotic species – House mouse ( Mus musculus) and Black rat ( Rattus rattus) – through direct 14C AMS dating of collagen from bones; (ii) we analysed recent material from Barn owl ( Tyto alba gracilirostris) roosting sites to evaluate its impact on Canarian shrew in the presence of introduced rodents. The new data strongly suggest that the extinction of Lava mouse was the result of an accumulative process of independent disappearances (or ‘local extinctions’) affecting the isolated populations. The timing of the introduction of the Black rat on the main islands (before Middle Age European contact in Lanzarote and after Middle Age European contact in Fuerteventura) matches with the last occurrence dates for the presence of Lava mouse on these islands, and are very probably their cause. The losses of these Lava mouse populations occurred in an asynchronous way, spreading across at least six centuries. On small islands, hyperpredation emerges as the most plausible process to explain the disappearance of the Lava mouse in the absence of rat populations, although stochastic processes can not be definitively excluded.


2008 ◽  
Vol 86 (9) ◽  
pp. 1068-1073 ◽  
Author(s):  
L. Ruffino ◽  
K. Bourgeois ◽  
E. Vidal ◽  
J. Icard ◽  
F. Torre ◽  
...  

The mechanisms by which introduced predators and long-lived seabirds interact and even coexist are still poorly known. Here, the interactions between the widely introduced black rat ( Rattus rattus (L., 1758)) and an endemic Mediterranean cavity-nesting seabird, the yelkouan shearwater ( Puffinus yelkouan (Acerbi, 1827)), were for the first time investigated for a set of 60 suitable breeding cavities throughout the entire breeding cycle of this seabird. Our results pointed out that rat visits to cavities were significantly higher when shearwaters had left the colony for their interbreeding exodus. Among the set of suitable breeding cavities, yelkouan shearwaters preferentially selected the deepest and the most winding cavities for breeding. Very few rat visits were recorded at the shearwater-occupied cavities and no predation event was recorded. These intriguing results reveal a low level of interaction between introduced black rats and yelkouan shearwaters, which may have facilitated their long-term coexistence for thousands of years on some Mediterranean islands.


2015 ◽  
Vol 42 (2) ◽  
pp. 86 ◽  
Author(s):  
Peter B. Banks ◽  
Helen M. Smith

Exotic species have had devastating impacts worldwide and are a major threat to native wildlife. Human commensal species (hereafter commensals) are a special class of exotic species that live largely off the resources associated with human activity. The encroachment of commensals from an urban area into surrounding bushland has been frequently overlooked as an important component of urban impacts, even though human-commensals are common to many urban regions globally. In this review, we present theoretical and empirical evidence for the processes and outcomes occurring when exotic commensal species encroach into native bushland. Specifically we ask when, how and why exotic commensal species encroach into bushland, what determines whether they establish, and what are the ecological consequences. We focus on the black rat, Rattus rattus, arguably the archetypal commensal species with a cosmopolitan distribution and the greatest potential for ecological damage of all the commensal rodents. We expect that the processes that we outline apply to other commensal species more broadly. We argue that commensals are in fact natives of the urban milieu and only become alien when they encroach into peri-urban bushland. We propose that the mechanisms of this encroachment will be different from those of other, non-commensal exotic species because urban areas act as dispersal hubs to overcome many of the barriers of invasion that other exotic species face. We suggest that resource supplementation by urban areas creates a great potential for promoting encroachment, invasion as well as impact. However, biotic and abiotic barriers to invasion are still relevant for commensals, highlighting the need to maintain the integrity of ecosystems and wildlife populations in urban edges so as to prevent commensal incursion. We examine how commensal black rats affect wildlife via three fundamental mechanisms, namely, predation, disease transfer and competition for resources, and also consider their possible positive impacts acting as functional replacements for lost natives. We conclude the review with an outline of research priorities and future directions that are essential for progressing our understanding of the ecology of commensal species.


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