scholarly journals Ecology, Taxonomic Status, and Conservation of the South Georgian Diving Petrel (Pelecanoides georgicus) in New Zealand

2021 ◽  
Author(s):  
◽  
Johannes Fischer

<p>Procellariiformes is a diverse order of seabirds under considerable pressure from onshore and offshore threats. New Zealand hosts a large and diverse community of Procellariiformes, but many species are at risk of extinction. In this thesis, I aim to provide an overview of threats and conservation actions of New Zealand’s Procellariiformes in general, and an assessment of the remaining terrestrial threats to the South Georgian Diving Petrel (Pelecanoides georgicus; SGDP), a Nationally Critical Procellariiform species restricted to Codfish Island (Whenua Hou), post invasive species eradication efforts in particular. I reviewed 145 references and assessed 14 current threats and 13 conservation actions of New Zealand’s Procellariiformes (n = 48) in a meta-analysis. I then assessed the terrestrial threats to the SGDP by analysing the influence of five physical, three competition, and three plant variables on nest-site selection using an information theoretic approach. Furthermore, I assessed the impacts of interspecific interactions at 20 SGDP burrows using remote cameras. Finally, to address species limits within the SGDP complex, I measured phenotypic differences (10 biometric and eight plumage characters) in 80 live birds and 53 study skins, as conservation prioritisation relies on accurate taxonomic classification. The results from the meta-analysis revealed that New Zealand’s Procellariiformes are at risk from various threats (x̅= 5.50 ± 0.34), but species also receive aid from several conservation actions (x̅= 7.19 ± 0.33). Results from a logistic regression showed that smaller species are more threatened onshore than offshore. The majority of the conservation actions appear in place where needed. However, habitat management, native predator control and the mitigation of risks associated with environmental stochasticity may need improvement. Analysis of SGDP nest-site selection showed dependency on mobile, steep, seaward-facing foredunes. Invasive plant species, the presence of conspecifics, or the presence of other seabird species did not influence SGDP nest-site selection. Assessment of interspecific interactions at SGDP burrows showed seven species occurring at burrows, but only Common Diving Petrels (P. urinatrix; CDP) interfered with SGDP breeding success. Assessment of phenotypic differences within the SGDP revealed that the New Zealand SGDP population differs in five biometric and three plumage characters from all other populations and warrants species status based on a species delimitation test with quantitative criteria. I propose to name this Critically Endangered species Pelecanoides taylorii sp. nov. These findings indicate that P. taylorii is of considerable conservation concern and additional measures, even after successful eradication of invasive species, may be required to safeguard this species. Based on the habitat preference, stochastic events, such as storms and storm surges, appear a major threat to P. taylorii. The assessed interspecific interactions at nest-sites, indicate competition with CDPs to be a minor threat. I propose a translocation as a potential strategy to relieve the pressure on P. taylorii, but further monitoring and research is needed to enable the implementation of such a conservation strategy.</p>

2021 ◽  
Author(s):  
◽  
Johannes Fischer

<p>Procellariiformes is a diverse order of seabirds under considerable pressure from onshore and offshore threats. New Zealand hosts a large and diverse community of Procellariiformes, but many species are at risk of extinction. In this thesis, I aim to provide an overview of threats and conservation actions of New Zealand’s Procellariiformes in general, and an assessment of the remaining terrestrial threats to the South Georgian Diving Petrel (Pelecanoides georgicus; SGDP), a Nationally Critical Procellariiform species restricted to Codfish Island (Whenua Hou), post invasive species eradication efforts in particular. I reviewed 145 references and assessed 14 current threats and 13 conservation actions of New Zealand’s Procellariiformes (n = 48) in a meta-analysis. I then assessed the terrestrial threats to the SGDP by analysing the influence of five physical, three competition, and three plant variables on nest-site selection using an information theoretic approach. Furthermore, I assessed the impacts of interspecific interactions at 20 SGDP burrows using remote cameras. Finally, to address species limits within the SGDP complex, I measured phenotypic differences (10 biometric and eight plumage characters) in 80 live birds and 53 study skins, as conservation prioritisation relies on accurate taxonomic classification. The results from the meta-analysis revealed that New Zealand’s Procellariiformes are at risk from various threats (x̅= 5.50 ± 0.34), but species also receive aid from several conservation actions (x̅= 7.19 ± 0.33). Results from a logistic regression showed that smaller species are more threatened onshore than offshore. The majority of the conservation actions appear in place where needed. However, habitat management, native predator control and the mitigation of risks associated with environmental stochasticity may need improvement. Analysis of SGDP nest-site selection showed dependency on mobile, steep, seaward-facing foredunes. Invasive plant species, the presence of conspecifics, or the presence of other seabird species did not influence SGDP nest-site selection. Assessment of interspecific interactions at SGDP burrows showed seven species occurring at burrows, but only Common Diving Petrels (P. urinatrix; CDP) interfered with SGDP breeding success. Assessment of phenotypic differences within the SGDP revealed that the New Zealand SGDP population differs in five biometric and three plumage characters from all other populations and warrants species status based on a species delimitation test with quantitative criteria. I propose to name this Critically Endangered species Pelecanoides taylorii sp. nov. These findings indicate that P. taylorii is of considerable conservation concern and additional measures, even after successful eradication of invasive species, may be required to safeguard this species. Based on the habitat preference, stochastic events, such as storms and storm surges, appear a major threat to P. taylorii. The assessed interspecific interactions at nest-sites, indicate competition with CDPs to be a minor threat. I propose a translocation as a potential strategy to relieve the pressure on P. taylorii, but further monitoring and research is needed to enable the implementation of such a conservation strategy.</p>


2019 ◽  
Vol 129 (2) ◽  
pp. 388-397
Author(s):  
Benjamin J Muller ◽  
Robin M Andrews ◽  
Lin Schwarzkopf ◽  
David A Pike

Abstract Microhabitat orientation and structure and the presence of conspecifics may strongly influence the choice of habitat. We studied how these variables influence retreat- and nest-site selection in gravid females of a globally successful invasive species, the Asian house gecko (Hemidactylus frenatus). When provided with various substrates (vertical and horizontal ceramic tiles, vertical and horizontal plywood tiles, horizontal bark over leaf litter, vertical bark over a log, and sand) gravid female geckos preferred to retreat to, and nest in, materials with crevices commonly found in urban habitats. When housed alone, gravid females most frequently retreated to vertical ceramic tile or wooden crevices, and 66.7% nested in vertical ceramic tiles. When housed with two other conspecifics, gravid females most frequently retreated to vertical ceramic tiles, but selected a wider range of nest sites. Overall, gravid geckos housed alone typically nested in the same substrates that they used as diurnal retreats; when housed in groups, however, females oviposited in locations different from those they selected as retreats. Thus, H. frenatus females use a wider range of substrates when conspecifics are present. Invasion success in this species might be driven, in part, by preferences for retreat and nest substrates that are common in human-dominated habitats.


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Marta Maziarz ◽  
Richard K. Broughton ◽  
Luca Pietro Casacci ◽  
Grzegorz Hebda ◽  
István Maák ◽  
...  

Abstract Background Interspecific interactions within ecological networks can influence animal fitness and behaviour, including nest-site selection of birds and ants. Previous studies revealed that nesting birds and ants may benefit from cohabitation, with interspecific attraction through their nest-site choice, but mutual interactions have not yet been tested. We explored a previously undescribed ecological link between ground-nesting birds and ants raising their own broods (larvae and pupae) within the birds’ nests in a temperate primeval forest of lowland Europe. We tested whether the occurrence of ant broods within bird nests resulted from a mutual or one-sided interspecific attraction that operated through nest-site choice and was modified by weather conditions. Results We found a non-random occupation of bird nests by ants raising their own broods within them, which indicated interspecific attraction driven solely by the ants. The birds’ preference to nest near tussocks of vegetation showed little overlap with the most frequent placement of ant colonies among fallen deciduous tree-leaves, dead wood and moss. Additionally, birds did not appear to select forest localities with high densities of ant colonies. The occurrence of ant broods within bird nests was also unrelated to bird nest placement near to specific habitat features. The attractiveness of bird nests to ants appeared to increase with the thermal activity of the birds warming their nests, and also during cool and wet weather when the occurrence of ant broods within bird nests was most frequent. Ants often remained in the nests after the birds had vacated them, with only a slight reduction in the probability of ant brood occurrence over time. Conclusions The natural patterns of bird nest colonisation by ants support the hypothesis of ants’ attraction to warm nests of birds to raise their broods under advantageous thermal conditions. Similar relationships may occur between other warm-blooded, nest-building vertebrates and nest-dwelling invertebrates, which depend on ambient temperatures. The findings advance our understanding of these poorly recognised interspecific interactions, and can inform future studies of ecological networks.


1996 ◽  
Vol 23 (3) ◽  
pp. 267-278 ◽  
Author(s):  
Graeme P. Elliott ◽  
Peter J. Dilks ◽  
Colin F.J. O'Donnell

2017 ◽  
Vol 28 (2) ◽  
pp. 216-227 ◽  
Author(s):  
JOHANNES H. FISCHER ◽  
IGOR DEBSKI ◽  
GRAEME A. TAYLOR ◽  
HEIKO U. WITTMER

SummarySmall seabird species are often threatened by predation from invasive species at their breeding colonies and considerable efforts are invested into mitigating this threat. However, invasive predators may not be the only onshore threat affecting small seabird species. The South Georgia Diving-petrel Pelecanoides georgicus (SGDP) is a small seabird species, considered ‘Nationally Critical’ in New Zealand. Our objective was to identify terrestrial threats to the species at their sole remaining breeding colony in New Zealand, Codfish Island (Whenua Hou), following the successful eradication of invasive predators. To achieve our objective, we assessed the influence of five physical, three competition/attraction and three plant variables on SGDP nest site selection with generalised linear models (GLMs) and compared models using an information theoretic approach. Models including the distance to sea, slope, aspect, and sand flux outperformed other models and showed selection for steep seaward-facing foredunes with mobile soils. No invasive plant and competition/attraction variables were included in the best performing models. These results suggest that, due to the proximity of their preferred nesting habitat to the springtide line and the overall fragility of the foredunes, SGDPs on Codfish Island are extremely vulnerable to stochastic events and catastrophes, such as storms and storm surges. Eradication efforts directed at invasive predators on Codfish Island appear thus insufficient to safeguard this SGDP colony, necessitating further conservation strategies to secure the continued survival of this population.


2019 ◽  
Author(s):  
Lauren Schaale ◽  
◽  
Joseph Baxley ◽  
Narcisa Pricope ◽  
Raymond M. Danner

2021 ◽  
Vol 26 ◽  
pp. e01524
Author(s):  
Karim Loucif ◽  
Mohamed Cherif Maazi ◽  
Moussa Houhamdi ◽  
Haroun Chenchouni

The Auk ◽  
2001 ◽  
Vol 118 (3) ◽  
pp. 727-735 ◽  
Author(s):  
Jason Jones ◽  
Raleigh J. Robertson

Abstract We examined habitat selection by breeding Cerulean Warblers (Dendroica cerulea) at three spatial scales in eastern Ontario over three years (1997–1999). Territories were characterized by well-spaced large trees, with high canopies and dense foliage cover at heights between 12–18 m. Nesting habitat additionally was characterized by dense foliage cover above 18 m. The results of our nest-patch (0.04 ha circle around nest) and nest-site (0.01 ha circle) analyses indicate that male Cerulean Warblers may take active roles in nest-site selection when selecting territories. We conclude from our nest-patch and nest-site selection analyses that territories likely contain multiple nest patches and sites and that male Cerulean Warblers may defend areas with multiple nest patches or sites, which may attract females to settle with them. Whether or not Cerulean Warbler females use nest-site availability as a mate- or territory-choice cue remains unknown. We also tested the validity of a commonly made assumption that a random sampling of habitat by researchers is representative of the habitat actually available to birds and found that, in our study area, the assumption was invalid. Taken together, our results point toward the need to maintain sizeable stands of mature, deciduous forest to ensure the persistence of Cerulean Warblers in eastern Ontario. Population characteristics such as lower minimum area requirements and a resilience to habitat disturbance may make that an easier job in eastern Ontario than elsewhere in this species' breeding range.


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