-
Welcome to BirdForum, the internet's largest birding community with thousands of members from all over the world. The forums are dedicated to wild birds, birding, binoculars and equipment and all that goes with it.
Please register for an account to take part in the discussions in the forum, post your pictures in the gallery and more.
Crimson Rosella (1 Viewer)
- Thread starter Richard Klim
- Start date
MJB
Well-known member
How many hours does Leo Joseph have in a day? More than the rest of the human race, it seems! Intriguing stuff in this paper...
MJB
Richard Klim
-------------------------
Richard Klim
-------------------------
Daniel Philippe
Well-known member
Peter Kovalik
Well-known member
Raoul F. H. Ribot, Mathew L. Berg, Emanuel Schubert, John A. Endler & Andrew T. D. Bennett. Plumage coloration follows Gloger's rule in a ring species. Journal of Biogeography. First published: 11 February 2019 https://doi.org/10.1111/jbi.13497
Abstract:
Aim
Animal coloration is expected to differ between populations in different habitats according to Gloger's rule, with darker animals found in more humid, vegetated or warmer environments. Yet despite considerable support across the globe, the mechanisms behind this biogeographical rule are currently still unclear. Exploiting a ring species with plumage coloration from crimson to pale yellow, we test Gloger's rule and the mechanisms behind phenotypic divergence.
Location
South‐eastern Australia.
Major taxa studied
Crimson rosellas (Platycercus elegans).
Methods
We combined three modelling approaches (spatial regression; random decision forest species distribution and conditional inference tree) to test the association between 10 environmental variables (based on long‐term climate data and remotely sensed reflectance of the land) and plumage coloration across the distribution of P. elegans. We also took in‐situ measurements of background coloration of dominant vegetation to examine the relationship between (a) background coloration measured locally and remotely, (b) P. elegans coloration and (c) known differences in visual sensitivity of the subspecies using species‐specific visual models.
Results
On both a continental and a local scale, the distribution of yellow‐red plumage coloration was strongly predicted by average rainfall, summer temperature and the Earth's reflectance between 620–670 nm. Remotely sensed radiance measures correlated strongly and positively with reflectance of the leaves of the dominant tree species at sites across the P. elegans distribution. Visual modelling indicated that differences in background colour could affect signalling efficacy in dim‐light conditions.
Main conclusions
Our study shows that the highly variable plumage coloration conforms to Gloger's rule, and indicates that background coloration of the vegetation and thermoregulation are likely to be important mechanisms. Our results also show that Gloger's rule can explain variation in pigmentary systems other than melanin, and highlight that selection from environmental variation could be an important force behind the geographic diversity found in ring species.
Abstract:
Aim
Animal coloration is expected to differ between populations in different habitats according to Gloger's rule, with darker animals found in more humid, vegetated or warmer environments. Yet despite considerable support across the globe, the mechanisms behind this biogeographical rule are currently still unclear. Exploiting a ring species with plumage coloration from crimson to pale yellow, we test Gloger's rule and the mechanisms behind phenotypic divergence.
Location
South‐eastern Australia.
Major taxa studied
Crimson rosellas (Platycercus elegans).
Methods
We combined three modelling approaches (spatial regression; random decision forest species distribution and conditional inference tree) to test the association between 10 environmental variables (based on long‐term climate data and remotely sensed reflectance of the land) and plumage coloration across the distribution of P. elegans. We also took in‐situ measurements of background coloration of dominant vegetation to examine the relationship between (a) background coloration measured locally and remotely, (b) P. elegans coloration and (c) known differences in visual sensitivity of the subspecies using species‐specific visual models.
Results
On both a continental and a local scale, the distribution of yellow‐red plumage coloration was strongly predicted by average rainfall, summer temperature and the Earth's reflectance between 620–670 nm. Remotely sensed radiance measures correlated strongly and positively with reflectance of the leaves of the dominant tree species at sites across the P. elegans distribution. Visual modelling indicated that differences in background colour could affect signalling efficacy in dim‐light conditions.
Main conclusions
Our study shows that the highly variable plumage coloration conforms to Gloger's rule, and indicates that background coloration of the vegetation and thermoregulation are likely to be important mechanisms. Our results also show that Gloger's rule can explain variation in pigmentary systems other than melanin, and highlight that selection from environmental variation could be an important force behind the geographic diversity found in ring species.
Björn Bergenholtz
(former alias "Calalp")
If of interest ...
Fishburn, M. 2022. A Crimson Rosella for Josephine. Journal of the History of Collections 34 (2): pp. 249–258:
Fishburn, M. 2022. A Crimson Rosella for Josephine. Journal of the History of Collections 34 (2): pp. 249–258:
