Biophysical correlates of relative abundances of marine megafauna at Ningaloo Reef, Western Australia

2007 ◽  
Vol 58 (7) ◽  
pp. 608 ◽  
Author(s):  
Jai C. Sleeman ◽  
Mark G. Meekan ◽  
Steven G. Wilson ◽  
Curt K. S. Jenner ◽  
Micheline N. Jenner ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Linear Models ◽  
Aerial Survey ◽  
Generalised Linear Models ◽  
Chl A ◽  
Ningaloo Reef ◽  
Minke Whales ◽  
Model Combining ◽  
Whale Sharks ◽  
Marine Megafauna

Changes in the relative abundance of marine megafauna (whales, dolphins, sharks, turtles, manta rays, dugongs) from aerial survey sightings in the waters adjacent to Ningaloo Reef between June 2000 and April 2002 are described. Generalised linear models were used to explore relationships between different trophic guilds of animals (based on animal sighting biomass estimates) and biophysical features of the oceanscape that were likely to indicate foraging habitats (regions of primary/secondary production) including sea surface temperature (SST), SST gradient, chlorophyll-a (Chl-a), bathymetry (BTH) and bathymetry gradient (BTHg). Relative biomass of krill feeders (i.e. minke whales, whale sharks, manta rays) were related to SST, Chl-a and bathymetry (model [AICc] weight = 0.45) and the model combining these variables explained a relatively large amount (32.3%) of the variation in relative biomass. Relative biomass of fish/cephalopod feeders (dolphins, sharks) were weakly correlated with changes in SST, whereas that of other invertebrate/macroalgal feeders (turtles, dugong) was weakly correlated with changes in steepness of the shelf (bathymetry gradient). Our results indicate that biophysical variables describe only a small proportion of the variance in the relative abundance and biomass of marine megafauna at Ningaloo reef.

Distribution and Abundance of Dugongs, Turtles, Dolphins and other Megafauna in Shark Bay, Ningaloo Reef and Exmouth Gulf, Western Australia

1997 ◽  
Vol 24 (2) ◽  
pp. 185 ◽  
Author(s):  
A. R. Preen ◽  
H. Marsh ◽  
I. R. Lawler ◽  
R. I. T. Prince ◽  
R. Shepherd
Keyword(s):  
Western Australia ◽  
Bottlenose Dolphins ◽  
Large Population ◽  
World Heritage ◽  
Shark Bay ◽  
Ningaloo Reef ◽  
Marine Park ◽  
Whale Sharks ◽  
Exmouth Gulf ◽  
Marine Megafauna

Strip-transect aerial surveys of Shark Bay, Ningaloo Reef and Exmouth Gulf were conducted during the winters of 1989 and 1994. These surveys were designed primarily to estimate the abundance and distribution of dugongs, although they also allowed sea turtles and dolphins, and, to a lesser extent, whales, manta rays and whale sharks to be surveyed. Shark Bay contains a large population of dugongs that is of international significance. Estimates of approximately 10000 dugongs resulted from both surveys. The density of dugongs is the highest recorded in Australia and the Middle East, where these surveys have been conducted. Exmouth Gulf and Ningaloo Reef are also important dugong habitats, each supporting in the order of 1000 dugongs. The estimated number of turtles in Shark Bay is comparable to the number in Exmouth Gulf plus Ningaloo Reef (7000–9000). The density of turtles in Ningaloo Reef and, to a lesser extent, Exmouth Gulf is exceptionally high compared with most other areas that have been surveyed by the same technique. Shark Bay supports a substantial population of bottlenose dolphins (2000–3000 minimum estimate). Exmouth Gulf and Ningaloo Reef were not significant habitats for dolphins during the winter surveys. Substantial numbers of whales (primarily humpbacks) and manta rays occur in northern and western Shark Bay in winter. Ningaloo Reef is an important area for whale sharks and manta rays in autumn and winter. The Shark Bay Marine Park excludes much of the winter habitats of the large vertebrate fauna of Shark Bay. In 1989 and 1994, more than half of all the dugongs were seen outside the Marine Park (57·4 and 50·7%, respectively). Approximately one-third to one-half of turtles and dolphins were seen outside the Marine Park (in 1989 and 1994 respectively: turtles, 43 and 27%; dolphins, 47 and 32%). Almost all the whales and most of the manta rays were seen outside the Marine Park. Expansion of the Shark Bay Marine Park, to bring it into alignment with the marine section of the Shark Bay World Heritage Area, would facilitate the appropriate management of these populations. This would also simplify the State– Commonwealth collaboration necessary to meet the obligations of World Heritage listing. The coastal waters of Western Australia north of the surveyed area (over 6000 km of coastline) are relatively poorly known and surveys of their marine megafauna are required for wise planning and management.

scholarly journals Does bathymetry drive coastal whale shark (Rhincodon typus)aggregations?

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4904 ◽  
Author(s):  
Joshua P. Copping ◽  
Bryce D. Stewart ◽  
Colin J. McClean ◽  
James Hancock ◽  
Richard Rees
Keyword(s):  
Primary Productivity ◽  
Linear Models ◽  
Prey Availability ◽  
Extensive Literature ◽  
Whale Shark ◽  
Generalised Linear Models ◽  
Rhincodon Typus ◽  
Bathymetric Data ◽  
Mesopelagic Zone ◽  
Whale Sharks

BackgroundThe whale shark (Rhincodon typus) is known to aggregate in a number of coastal locations globally, however what causes these aggregations to form where they do is largely unknown. This study examines whether bathymetry is an important driver of coastal aggregation locations forR. typusthrough bathymetry’s effect on primary productivity and prey availability. This is a global study taking into account all coastal areas withinR. typus’range.MethodsR. typusaggregation locations were identified through an extensive literature review. Global bathymetric data were compared atR. typusaggregation locations and a large random selection of non-aggregation areas. Generalised linear models were used to assess which bathymetric characteristic had the biggest influence on aggregation presence.ResultsAggregation sites were significantly shallower than non-aggregation sites and in closer proximity to deep water (the mesopelagic zone) by two orders of magnitude. Slope at aggregation sites was significantly steeper than non-aggregation sites. These three bathymetric variables were shown to have the biggest association with aggregation sites, with up to 88% of deviation explained by the GLMs.DiscussionThe three key bathymetric characteristics similar at the aggregation sites are known to induce upwelling events, increase primary productivity and consequently attract numerous other filter feeding species. The location of aggregation sites in these key areas can be attributed to this increased prey availability, thought to be the main reasonR. typusaggregations occur, extensively outlined in the literature. The proximity of aggregations to shallow areas such as reefs could also be an important factor why whale sharks thermoregulate after deep dives to feed. These findings increase our understanding of whale shark behaviour and may help guide the identification and conservation of further aggregation sites.

scholarly journals Factors affecting presence and relative abundance of the Endangered volcano rabbit Romerolagus diazi, a habitat specialist

Oryx ◽  
2021 ◽  
pp. 1-10
Author(s):  
Felipe Osuna ◽  
Roger Guevara ◽  
Enrique Martínez-Meyer ◽  
Raúl Alcalá ◽  
Alejandro Espinosa de los Monteros
Keyword(s):  
Sierra Nevada ◽  
Relative Abundance ◽  
Linear Models ◽  
Cattle Grazing ◽  
Patch Occupancy ◽  
Factors Affecting ◽  
Rock Cover ◽  
Volcanic Fields ◽  
Mountain Grasslands ◽  
Insight Into

Abstract Habitat specialists are particularly vulnerable to extinction when habitat conditions are altered. Information on the habitat use of such species is thus important because it provides insight into factors that influence distribution and abundance, which is crucial for conservation. Here, we aimed to identify factors that influence the patterns of presence and abundance of the Endangered volcano rabbit Romerolagus diazi, a rare leporid with a patchy distribution. Through exhaustive sampling of its range in the Sierra Chichinautzin and Sierra Nevada volcanic fields, Mexico, and using generalized linear models, we found that the probability of patch occupancy was higher where bunchgrass cover exceeded 75%, rock cover exceeded 5%, no cattle grazing was observed and human settlements were at least 7 km away. Patches with greater relative abundance were those with similar characteristics, but located at elevations > 3,600 m, and with rock cover < 15%. Cattle grazing was identified as a major threat to local populations of the volcano rabbit, particularly in the Sierra Chichinautzin. Because of the significance of bunchgrasses for this species, the protection of the mountain grasslands is required in both volcanic fields.

Nonnull asymptotic distributions of three classic criteria in generalised linear models

Biometrika ◽  
1994 ◽  
Vol 81 (4) ◽  
pp. 709-720 ◽  
Author(s):  
GAUSS M. CORDEIRO ◽  
DENISE A. BOTTER ◽  
SILVIA L. DE PAULA FERRARI
Keyword(s):  
Linear Models ◽  
Asymptotic Distributions ◽  
Generalised Linear Models

scholarly journals Spatial and temporal patterns of nature-based tourism interactions with whale sharks (Rhincodon typus) at Ningaloo Reef, Western Australia

2014 ◽  
Vol 148 ◽  
pp. 109-119 ◽  
Author(s):  
Douglas J. Anderson ◽  
Halina T. Kobryn ◽  
Brad M. Norman ◽  
Lars Bejder ◽  
Julian A. Tyne ◽  
...  
Keyword(s):  
Western Australia ◽  
Temporal Patterns ◽  
Spatial And Temporal Patterns ◽  
Rhincodon Typus ◽  
Ningaloo Reef ◽  
Whale Sharks

Forty years of dietary studies on barn owl (Tyto alba) reveal long term trends in diversity metrics of small mammal prey

2018 ◽  
Vol 68 (2) ◽  
pp. 129-146 ◽  
Author(s):  
Giuliano Milana ◽  
Luca Luiselli ◽  
Giovanni Amori
Keyword(s):  
Species Richness ◽  
Relative Abundance ◽  
Negative Correlation ◽  
Linear Models ◽  
Prey Availability ◽  
Diversity Indices ◽  
Barn Owl ◽  
Tyto Alba ◽  
Local Conditions ◽  
Over Time

AbstractThe diet of predators is influenced by local conditions (e.g., characteristics of habitat and microhabitat, seasonality, prey availability) and therefore tends to change across time. In this paper, the diet composition of the barn owl (Tyto alba) in Italy was studied using a meta-analysis of 47 articles (covering 212 independent sites, with multiple surveys for some sites, thus giving a total of 290 datasets) between 1972 and 2012. General Linear Models were used to assess the effects of year and study site on four distinct diversity indices (species richness, dominance, Shannon-Weaver diversity and equitability). The year of data collection was a factor used in all analyses. Year had a greater effect than study site on all diversity indices, but the effect was not significant for the evenness and the species richness. However, dietary dominance increased significantly over the years, the Shannon-Weaver index of diversity decreased significantly over time, and equitability also decreased significantly over time. The relative abundance of various species of rodents did not increase/decrease progressively over the years, although there were inter-annual fluctuations. On the other hand, the relative abundance of insectivores tended to decrease with time, and there was a significantly negative correlation between year and the frequency of consumption of Sorex spp. and a marginally significant negative correlation for Crocidura leucodon.

Second order asymptotics for score tests in generalised linear models

Biometrika ◽  
1995 ◽  
Vol 82 (2) ◽  
pp. 426-432 ◽  
Author(s):  
FRANCISCO CRIBARI-NETO ◽  
SILVIA L. P. FERRARI
Keyword(s):  
Linear Models ◽  
Second Order ◽  
Generalised Linear Models ◽  
Score Tests ◽  
Second Order Asymptotics

Intensification of future low-flow events in relation to projected changes in large-scale climate drivers due to climate change

2021 ◽  
Author(s):  
Pallavi Goswami ◽  
Arpita Mondal ◽  
Christoph Rüdiger ◽  
Tim J. Peterson
Keyword(s):  
Climate Change ◽  
Large Scale ◽  
Linear Models ◽  
Southern Oscillation ◽  
Value Theory ◽  
Extreme Value ◽  
Low Flow ◽  
Generalised Linear Models ◽  
Southeast Australia ◽  
The Future

&lt;p&gt;Large-scale climate processes such as the El Nino Southern Oscillation (ENSO), Indian Ocean Dipole (IOD) and Southern Annular Mode (SAM) influence the hydro-climatology of Southeast Australia (SEA). In the present study, we show that low-flow events in many catchments in SEA are significantly influenced by variability in these climate drivers. Extreme value distributions and Generalised Linear Models (GLMs) are used here to model low-flow characteristics such as intensity, duration and frequency with respect to these climate drivers. Further, we study how the future projections of ENSO, IOD and SAM are likely to evolve under climate change by examining the projected values of their representative indices and how they will impact low-flow events in the region. It is found that the future dry phases of these climate drivers are likely to be more dry than those in the historic period. This in turn is expected to lead to intensification of low-flow events in the future, resulting in lower availability of fresh water during occurrences of the dry phases of these climate drivers. Thus, climate change in the future is expected to significantly influence future low-flow events in the region thereby making it even more crucial for water managers to adequately manage and ensure water availability.&lt;/p&gt;&lt;p&gt;&lt;br&gt;Keywords: low-flows, ENSO, IOD, SAM, Extreme Value Theory, Generalised Linear Models, Southeast Australia, CMIP5, RCP8.5.&lt;/p&gt;

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