scholarly journals Reproductive capacity of an endangered and recovering population of humpback whales in the Southern Hemisphere

2020 ◽  
Vol 643 ◽  
pp. 219-227
Author(s):  
G Chero ◽  
R Pradel ◽  
S Derville ◽  
C Bonneville ◽  
O Gimenez ◽  
...  
Keyword(s):  
New Caledonia ◽  
Monitoring Program ◽  
Humpback Whale ◽  
Breeding Population ◽  
Reproductive Capacity ◽  
Strong Increase ◽  
Past Century ◽  
Mammal Species ◽  
Recovery Potential ◽  
Calving Rate

Estimating demographic parameters is essential to assessing the recovery potential of severely depleted populations of marine mammal species such as the baleen whales, which were decimated by commercial whaling of the past century. The Oceania humpback whale Megaptera novaeangliae population is classified as endangered by the IUCN because of low numbers and a slow recovery rate. Nevertheless, an anomalously strong increase has recently been detected in the New Caledonia breeding population. To determine the drivers of population growth, reproductive parameters were estimated for the first time for a humpback whale population of Oceania. Based on an extensive monitoring program (1995-2018), recapture histories were reconstructed for 607 females and incorporated in multi-event capture-recapture models. As the females’ ages were generally unknown (87%), 2 models with contrasting age scenarios were investigated. For females of unknown age, the mature scenario assumed maturity at the first encounter, while the immature scenario assumed immaturity within 7 yr after the first encounter, unless the female was encountered breeding. These models respectively resulted in a calving interval of 1.49 yr (95% CI: 1.21-2.08) or 2.83 yr (95% CI: 2.28-3.56) and a calving rate of 0.67 or 0.35. The relatively high calving rate modelled by the mature model is consistent with high pregnancy rates recently observed in the migratory corridors of the Kermadec Islands and on the feeding grounds of the Antarctic Peninsula. Therefore, our results suggest that the recovery of the New Caledonia humpback whale population from past exploitation may be partially driven by an increased reproductive capacity.

scholarly journals Migratory insights from singing humpback whales recorded around central New Zealand

2020 ◽  
Vol 7 (11) ◽  
pp. 201084
Author(s):  
Victoria E. Warren ◽  
Rochelle Constantine ◽  
Michael Noad ◽  
Claire Garrigue ◽  
Ellen C. Garland
Keyword(s):  
New Zealand ◽  
East Coast ◽  
New Caledonia ◽  
South Pacific ◽  
Humpback Whale ◽  
Breeding Population ◽  
Population Connectivity ◽  
Humpback Whales ◽  
Migratory Routes ◽  
Migratory Corridor

The migration routes of wide-ranging species can be difficult to study, particularly at sea. In the western South Pacific, migratory routes of humpback whales between breeding and feeding areas are unclear. Male humpback whales sing a population-specific song, which can be used to match singers on migration to a breeding population. To investigate migratory routes and breeding area connections, passive acoustic recorders were deployed in the central New Zealand migratory corridor (2016); recorded humpback whale song was compared to song from the closest breeding populations of East Australia and New Caledonia (2015–2017). Singing northbound whales migrated past New Zealand from June to August via the east coast of the South Island and Cook Strait. Few song detections were made along the east coast of the North Island. New Zealand song matched New Caledonia song, suggesting a migratory destination, but connectivity to East Australia could not be ruled out. Two song types were present in New Zealand, illustrating the potential for easterly song transmission from East Australia to New Caledonia in this shared migratory corridor. This study enhances our understanding of western South Pacific humpback whale breeding population connectivity, and provides novel insights into the dynamic transmission of song culture.

scholarly journals Long-term shifts in the colony size structure of coral populations along the Great Barrier Reef

2020 ◽  
Vol 287 (1936) ◽  
pp. 20201432
Author(s):  
Andreas Dietzel ◽  
Michael Bode ◽  
Sean R. Connolly ◽  
Terry P. Hughes
Keyword(s):  
Great Barrier Reef ◽  
Colony Size ◽  
Size Structure ◽  
Coral Cover ◽  
Spatial Scales ◽  
Reproductive Capacity ◽  
Barrier Reef ◽  
Size Frequency Distribution ◽  
Coral Colony ◽  
Recovery Potential

The age or size structure of a population has a marked influence on its demography and reproductive capacity. While declines in coral cover are well documented, concomitant shifts in the size-frequency distribution of coral colonies are rarely measured at large spatial scales. Here, we document major shifts in the colony size structure of coral populations along the 2300 km length of the Great Barrier Reef relative to historical baselines (1995/1996). Coral colony abundances on reef crests and slopes have declined sharply across all colony size classes and in all coral taxa compared to historical baselines. Declines were particularly pronounced in the northern and central regions of the Great Barrier Reef, following mass coral bleaching in 2016 and 2017. The relative abundances of large colonies remained relatively stable, but this apparent stability masks steep declines in absolute abundance. The potential for recovery of older fecund corals is uncertain given the increasing frequency and intensity of disturbance events. The systematic decline in smaller colonies across regions, habitats and taxa, suggests that a decline in recruitment has further eroded the recovery potential and resilience of coral populations.

scholarly journals Impact of Recent Climate Change on Water-Use Efficiency Strategies of Larix sibirica in the Altai-Sayan Mountain Range

Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1103
Author(s):  
Olga V. Churakova (Sidorova) ◽  
Marina V. Fonti ◽  
Rolf T. W. Siegwolf ◽  
Matthias Saurer ◽  
Vladimir S. Myglan
Keyword(s):  
Water Use ◽  
Air Temperature ◽  
Siberian Larch ◽  
Larix Sibirica ◽  
Strong Increase ◽  
Past Century ◽  
Mountain Range ◽  
The Past ◽  
Recent Climate ◽  
The Impact

A strong increase in the mean annual air temperature during the past 50 years by up to 0.54 °C was recorded in the Altai region (45°–52° N; 84°–99° E) compared to the global value of 0.07 °C over the period 1901–2008. The impact of the climatic changes on the hydrology are complex in these mountainous forest ecosystems and not fully understood. We aim to reveal differences in the intrinsic water-use efficiencies (iWUE) strategy by larch (Larix sibirica Ledeb.) derived from stable carbon isotopes at contrasting sites, ranging from the steppe (Ersin, Chadan) to high-elevation (Mongun, Koksu) sites of the Altai over the past century. The iWUE trends increased rapidly for all study sites except Chadan, where a decreasing trend after 2010 has been observed. This decline can be related to increased amount of precipitation compared to increased drought at the other sites. In general, the iWUE is increased up to 14% (1985–2019 compared to 1919–1984), which is lower compared to other studies across the globe likely due to harsh climatic conditions. Vapor pressure deficit and maximal air temperature are impacting Siberian larch significantly and affecting their iWUE differently at the high-elevated and steppe sites of the Altai over the past century.

Male mate choice and male-male competition coexist in the humpback whale (Megaptera novaeangliae)

2002 ◽  
Vol 80 (4) ◽  
pp. 745-755 ◽  
Author(s):  
Alison S Craig ◽  
Louis M Herman ◽  
Adam A Pack
Keyword(s):  
Mate Choice ◽  
Reproductive Potential ◽  
Humpback Whale ◽  
Male Competition ◽  
Megaptera Novaeangliae ◽  
Reproductive Season ◽  
Humpback Whales ◽  
Male Mate Choice ◽  
Calving Rate ◽  
Male Mate

Male humpback whales (Megaptera novaeangliae) outnumber females on the winter grounds and compete physically for proximity to females. Analyses of identification photographs collected in Hawai'i from 1976 through 1995 and scan samples collected in 1998 showed that (i) reproductive potential (calving rate) for the following winter was greater for females without a calf than females with a calf, (ii) females without a calf were less likely to be found alone and more likely to be found in large pods than females with a calf, (iii) individual females were found in larger pods when without a calf than when with a calf, (iv) the probability of females with a calf being escorted by one or more males increased as the reproductive season progressed, and (v) head lunges occurred more commonly in all-adult pods than in pods containing a calf. We concluded that male humpback whales associate preferentially with females with high reproductive potential, that the attractiveness of individual females varies with their status (with a calf versus without a calf), that males become progressively less choosy over the course of the reproductive season as females without a calf become increasingly rare on the winter grounds, and that males expend more energy in competition over females without a calf than females with a calf.

Larval intraspecific competition for food in the European grapevine moth Lobesia botrana

2014 ◽  
Vol 104 (4) ◽  
pp. 517-524 ◽  
Author(s):  
D. Thiéry ◽  
K. Monceau ◽  
J. Moreau
Keyword(s):  
Life History ◽  
Intraspecific Competition ◽  
Life History Traits ◽  
Larval Mortality ◽  
Lobesia Botrana ◽  
Reproductive Capacity ◽  
Strong Increase ◽  
European Grapevine Moth ◽  
Grapevine Moth ◽  
Larval Crowding

AbstractEffective pest management with lower amounts of pesticides relies on accurate prediction of insect pest growth rates. Knowledge of the factors governing this trait and the resulting fitness of individuals is thus necessary to refine predictions and make suitable decisions in crop protection. The European grapevine moth, Lobesia botrana, the major pest of grapes in Europe, is responsible for huge economic losses. Larvae very rarely leave the grape bunch on which they were oviposited and thus cannot avoid intraspecific competition. In this study, we determined the impact of intraspecific competition during the larval stage on development and adult fitness in this species. This was tested by rearing different numbers of larvae on an artificial diet and measuring developmental and reproductive life history traits. We found that intraspecific competition during larval development has a slight impact on the fitness of L. botrana. The principal finding of this work is that larval density has little effect on the life history traits of survivors. Thus, the timing of eclosion, duration of subsequent oviposition, fecundity appears to be more uniform in L. botrana than in other species. The main effect of larval crowding was a strong increase of larval mortality at high densities whereas the probability of emergence, sex ratio, pupal mass, fecundity and longevity of mated females were not affected by larval crowding. Owing to increased larval mortality at high larval densities, we hypothesized that mortality of larvae at high densities provided better access to food for the survivors with the result that more food was available per capita and there were no effect on fitness of survivors. From our results, larval crowding alters the reproductive capacity of this pest less than expected but this single factor should now be tested in interaction with limited resources in the wild.

The effectiveness and cost of camera traps for surveying small reptiles and critical weight range mammals: a comparison with labour-intensive complementary methods

2015 ◽  
Vol 42 (5) ◽  
pp. 414 ◽  
Author(s):  
Dustin J. Welbourne ◽  
Christopher MacGregor ◽  
David Paull ◽  
David B. Lindenmayer
Keyword(s):  
Monitoring Program ◽  
Camera Traps ◽  
Camera Trapping ◽  
Mammal Species ◽  
Critical Weight ◽  
Complementary Methods ◽  
Incidence Data ◽  
Trapping Method ◽  
The Difference

Context Biodiversity studies often require wildlife researchers to survey multiple species across taxonomic classes. To detect terrestrial squamate and mammal species, often multiple labour-intensive survey techniques are required. Camera traps appear to be more effective and cost-efficient than labour-intensive methods for detecting some mammal species. Recent developments have seen camera traps used for detecting terrestrial squamates. However, the performance of camera traps to survey terrestrial squamate and mammal species simultaneously has not been evaluated. Aim We compared the effectiveness and financial cost of a camera trapping method capable of detecting small squamates and mammals with a set of labour-intensive complementary methods, which have been used in a long-term monitoring program. Methods We compared two survey protocols: one employed labour-intensive complementary methods consisting of cage traps, Elliott traps and artificial refuges; the second utilised camera traps. Comparisons were made of the total number of species detected, species detectability, and cost of executing each type of survey. Key results Camera traps detected significantly more target species per transect than the complementary methods used. Although camera traps detected more species of reptile per transect, the difference was not significant. For the initial survey, camera traps were more expensive than the complementary methods employed, but for realistic cost scenarios camera traps were less expensive in the long term. Conclusions Camera traps are more effective and less expensive than the complementary methods used for acquiring incidence data on terrestrial squamate and mammal species. Implications The camera trapping method presented does not require customised equipment; thus, wildlife managers can use existing camera trapping equipment to detect cryptic mammal and squamate species simultaneously.

scholarly journals Breeding population dynamics of Common Tern Sterna hirundo and associated gull species with overview of conservation management in continental Slovenia

Acrocephalus ◽  
2019 ◽  
Vol 40 (180-181) ◽  
pp. 5-48
Author(s):  
Damijan Denac ◽  
Luka Božič
Keyword(s):  
Breeding Population ◽  
Breeding Habitat ◽  
Common Tern ◽  
Strong Increase ◽  
Special Focus ◽  
Moderate Increase ◽  
Sterna Hirundo ◽  
Danube Basin ◽  
Conservation Measures

AbstractAn overview of the long-term (1980–2019) population development of colonial Laridae species in continental part of Slovenia, their nest sites at anthropogenic water bodies, and various conservation measures with special focus on Common Tern Sterna hirundo along the Slovenian/border part of the Drava River is given. Breeding of these species occurs only on the westernmost fringes of the Pannonian plain, on lowland floodplains of the main rivers of the Danube Basin. Altogether, breeding of Common Tern and Black-headed Gull Larus ridibundus was recorded at 11 and 10 sites, respectively. Lake Ptuj is the single site with mixed-species colony residing there in all years of the study period, while at Ormož (two sites) it was established during the early 1990s in the Slovenian territory but moved completely to the Croatian side by the second half of the 2010s. At all other sites, a suitable breeding habitat became available or was provided by management in just a few years, or created only recently. The percentage of Common Tern national population breeding in continental Slovenia was usually well above 50% throughout the 1980s and 1990s (52–136 pairs), while in the last 16 years (77–258 pairs) it ranged between 40.8% and 69.0%. Breeding of Black-headed Gull remains largely limited to continental Slovenia. Overall, continental populations of both species in the last few years have been substantially higher compared to the most of the study period. Long-term trends were estimated as a moderate increase for Common Tern and a strong increase for Black-headed Gull. Since 2006, the Mediterranean Gull L. melanocephalus has been a regular breeder at Lake Ptuj (up to 28 pairs), the only such site in Slovenia. Three general types of conservation measures implemented at different nesting locations are described in detail: (1) measures to create/increase the total surface of breeding habitat – the construction of new breeding structures, such as artificial islands and nesting rafts, (2) measures to maintain and enhance breeding habitat through recurring management activities, and (3) measures aimed to increase chick/nest survival and improve breeding success.

scholarly journals A Convolutional Neural Network for Automated Detection of Humpback Whale Song in a Diverse, Long-Term Passive Acoustic Dataset

2021 ◽  
Vol 8 ◽  
Author(s):  
Ann N. Allen ◽  
Matt Harvey ◽  
Lauren Harrell ◽  
Aren Jansen ◽  
Karlina P. Merkens ◽  
...  
Keyword(s):  
Neural Network ◽  
Convolutional Neural Network ◽  
Characteristic Curve ◽  
Humpback Whale ◽  
Learning Approaches ◽  
Spatial And Temporal Patterns ◽  
Mammal Species ◽  
Diverse Range ◽  
Acoustic Data ◽  
Passive Acoustic

Passive acoustic monitoring is a well-established tool for researching the occurrence, movements, and ecology of a wide variety of marine mammal species. Advances in hardware and data collection have exponentially increased the volumes of passive acoustic data collected, such that discoveries are now limited by the time required to analyze rather than collect the data. In order to address this limitation, we trained a deep convolutional neural network (CNN) to identify humpback whale song in over 187,000 h of acoustic data collected at 13 different monitoring sites in the North Pacific over a 14-year period. The model successfully detected 75 s audio segments containing humpback song with an average precision of 0.97 and average area under the receiver operating characteristic curve (AUC-ROC) of 0.992. The model output was used to analyze spatial and temporal patterns of humpback song, corroborating known seasonal patterns in the Hawaiian and Mariana Islands, including occurrence at remote monitoring sites beyond well-studied aggregations, as well as novel discovery of humpback whale song at Kingman Reef, at 5∘ North latitude. This study demonstrates the ability of a CNN trained on a small dataset to generalize well to a highly variable signal type across a diverse range of recording and noise conditions. We demonstrate the utility of active learning approaches for creating high-quality models in specialized domains where annotations are rare. These results validate the feasibility of applying deep learning models to identify highly variable signals across broad spatial and temporal scales, enabling new discoveries through combining large datasets with cutting edge tools.

Selection for increased cranial capacity in small mammals during a century of urbanization

2020 ◽  
Author(s):  
C DePasquale ◽  
X Li ◽  
M Harold ◽  
S Mueller ◽  
S McLaren ◽  
...  
Keyword(s):  
Small Mammal ◽  
Brain Size ◽  
Behavioral Flexibility ◽  
Rural Populations ◽  
Past Century ◽  
Cranial Capacity ◽  
Carnegie Museum ◽  
Mammal Species ◽  
Rapid Urbanization ◽  
Urban Populations

Abstract Urbanization is a selective force that is known to drive changes in the population dynamics of wildlife. How animals adapt to changing environmental conditions is crucial to their survival in these environments. Relative brain size, or cranial capacity, is a known proxy of behavioral flexibility, and can be used to assess how well a species has adapted to a particular environment. We examined changes in cranial capacity in a time series of small mammal skulls collected from urban and rural populations in southwestern Pennsylvania. Skulls from urban populations were collected from Allegheny County, an area that experienced rapid urbanization over the past century, and skulls of rural populations from the Powdermill Nature Reserve of the Carnegie Museum, which has remained relatively unchanged forest over the same period. Our results show that Peromyscus leucopus and Microtus pennsylvanicus from urban populations had significantly greater cranial capacity than their rural counterparts, but the opposite was true for Eptesicus fuscus. We found no difference in relative cranial capacity across time in any of the small mammal species. Our results suggest that a larger cranial capacity is selected for in an urban environment and reinforces the hypothesis that behavioral flexibility is important for animals to adapt to novel environments.

Introduced species in New Zealand ? Their impacts on a biodiversity hotspot

2010 ◽  
Vol 16 (4) ◽  
pp. 230 ◽  
Author(s):  
Mark N. H. Seabrook-Davision ◽  
Dianne H. Brunton
Keyword(s):  
New Zealand ◽  
Introduced Species ◽  
New Caledonia ◽  
Biodiversity Hotspot ◽  
Rapid Expansion ◽  
Brushtail Possum ◽  
Mammal Species ◽  
Mustela Nivalis ◽  
Mammalian Predators ◽  
Mustela Furo

The issue of naturalization of introduced species to New Zealand was raised in an article in Nature (Ritchie 1922a Thompson 1922) 88 years ago. Here, we take the opportunity to assess the impacts of introduced species to the islands of New Zealand, one of the only entire countries, such as Madagascar, Japan, Philippines and New Caledonia to be described as a biodiversity hotspot (Reid 1998; Abbitt et al. 2000; Smith et al. 2001; Mittermeier et al. 2004). Between 1769 and 1919, 1170 species were recorded as being introduced to New Zealand (Thompson 1922) (Table 1). Ritchie (1922) reviewed the publication of Thompson?s inventory and warned against the introduction of exotic species without proper planning and assessment of the impacts on the existing biota. The warning was given because of New Zealand?s biodiversity had evolved in the absence of mammalian predators. Many bird, reptile and invertebrate species had limited defences against mammal species such as rats Rattus spp, mustelids (Stoat Mustela erminea, Ferret Mustela furo and Weasel Mustela nivalis vulgari), Brushtail Possum Trichosurus vulpectula and Cat Felis cattus. At the beginning of the 20th century, most of New Zealand?s large land vertebrates were extinct or threatened with extinction. The rapid expansion of mustelids, rats and Cat had caused considerable contractions in the distribution of large ground birds such as Kakapo Strigops habroptilus, South Island Takahe Porphyrio mantelli hochstetteri and species of waterfowl.

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