Comparisons through time and space suggest rapid evolution of dispersal behaviour in an invasive species

2009 ◽  
Vol 36 (1) ◽  
pp. 23 ◽  
Author(s):  
Ross A. Alford ◽  
Gregory P. Brown ◽  
Lin Schwarzkopf ◽  
Benjamin L. Phillips ◽  
Richard Shine
Keyword(s):  
Rapid Evolution ◽  
Early Years ◽  
Radio Tracking ◽  
Evolution Of Dispersal ◽  
Dispersal Behaviour ◽  
Invasion Front ◽  
Maximum Period ◽  
Tropical Australia ◽  
Dispersal Abilities ◽  
Free Ranging

During a biological invasion, we expect that the expanding front will increasingly become dominated by individuals with better dispersal abilities. Over many generations, selection at the invasion front thus will favour traits that increase dispersal rates. As a result of this process, cane toads (Bufo marinus) are now spreading through tropical Australia about 5-fold faster than in the early years of toad invasion; but how have toads changed to make this happen? Here we present data from radio-tracking of free-ranging cane toads from three populations (spanning a 15-year period of the toads’ Australian invasion, and across 1800 km). Our data reveal dramatic shifts in behavioural traits (proportion of nights when toads move from their existing retreat-site to a new one, and distance between those successive retreat-sites) associated with the rapid acceleration of toad invasion. Over a maximum period of 70 years (~50 generations), cane toads at the invasion front in Australia apparently have evolved such that populations include a higher proportion of individuals that make long, straight moves.

scholarly journals The effects of weather conditions on dispersal behaviour of free-ranging lizards (Tiliqua, Scincidae) in tropical Australia

2013 ◽  
Vol 28 (2) ◽  
pp. 440-449 ◽  
Author(s):  
Samantha J. Price-Rees ◽  
Tom Lindström ◽  
Gregory P. Brown ◽  
Richard Shine
Keyword(s):  
Weather Conditions ◽  
Dispersal Behaviour ◽  
Tropical Australia ◽  
Free Ranging

scholarly journals Unprecedented account of mortality and morbidity in free ranging Formosan Pangolin (Manis pentadactyla pentadactyla)

2018 ◽  
Author(s):  
Nick Ching-Min Sun ◽  
Bharti Arora ◽  
Jing-Shiun Lin ◽  
Wen-Chi Lin ◽  
Meng-Jou Chi ◽  
...  
Keyword(s):  
Success Rate ◽  
Illegal Trade ◽  
Wild Animals ◽  
Radio Tracking ◽  
Mortality And Morbidity ◽  
Manis Pentadactyla ◽  
Rescue Center ◽  
Free Ranging

AbstractGlobally, pangolins are overt for poaching and illegal trade, but Taiwan projects totally a contrary image where their population is stable and increasing. This paper illustrated the factors responsible for causing mortality and morbidity in free ranging Formosan pangolin (M. pentadactyla pentadactyla). Results from radio-tracking showed that Formosan pangolins are highly susceptible to stuck in tree hallows or ground burrows despite being proficient burrowers, and killed by gin traps, especially during the dryer season. Whilst the data consolidated from the Pingtung Rescue Center for Endangered Wild Animals illustrated the trauma (73.0%) was the major reason of causing morbidity in Formosan pangolin. The gin traps were the leading cause of trauma (77.8%) along with tail injuries caused by dog attack (20.4%). Despite all the pressing data about the injuries Taiwan, it is able to establish substantial success rate in rescuing and releasing pangolins through consolidating and applying valuable information among the rescue centers in the span of two decades. Taiwan has made a phenomenal progress in sustaining a salubrious population of pangolin but the situation requires continuous examination to ensure the existence of this species on the island.

scholarly journals Spinal arthritis in invasive cane toads is linked to rate of dispersal as well as to latitude

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Gregory P. Brown ◽  
Lin Schwarzkopf ◽  
Ross A. Alford ◽  
Deborah Bower ◽  
Richard Shine
Keyword(s):  
Spatial Sampling ◽  
Climatic Effects ◽  
Rhinella Marina ◽  
Invasion Front ◽  
Tropical Conditions ◽  
High Incidence ◽  
Tropical Australia ◽  
Tropical Climates ◽  
Initial Research ◽  
Living Bacteria

Abstract Initial research on the spread of cane toads (Rhinella marina) through tropical Australia reported a high incidence of spinal arthritis (spondylosis) in toads at the invasion front (where toads disperse rapidly), but not in areas colonized earlier (where toads are more sedentary). The idea that spondylosis was a cost of rapid dispersal was challenged by wider spatial sampling which linked rates of spondylosis to hot (tropical) climates rather than to dispersal rates. Here, the authors of these competing interpretations collaborate to reinterpret the data. Our reanalysis supports both previous hypotheses; rates of spondylosis are higher in populations established by fast-dispersing toads, and are higher in tropical than in temperate environments; they are also higher in larger toads. The functional reason for climatic effects is unclear, but might involve effects on the soil-living bacteria involved in the induction of spondylosis; and/or may reflect higher movement (as opposed to dispersal) or more pronounced dry-season aggregation rates of toads in tropical conditions.

Rapid expansion of the cane toad (Bufo marinus) invasion front in tropical Australia

2007 ◽  
Vol 32 (2) ◽  
pp. 169-176 ◽  
Author(s):  
BENJAMIN L. PHILLIPS ◽  
GREGORY P. BROWN ◽  
MATTHEW GREENLEES ◽  
JONATHAN K. WEBB ◽  
RICHARD SHINE
Keyword(s):  
Bufo Marinus ◽  
Rapid Expansion ◽  
Cane Toad ◽  
Invasion Front ◽  
Tropical Australia ◽  
Toad Bufo

Dispersal of Juvenile Brushtail Possums, Trichosurus vulpecula, after a Control Operation

1997 ◽  
Vol 24 (3) ◽  
pp. 279 ◽  
Author(s):  
P. E. Cowan ◽  
R. E. Brockie ◽  
R. N. Smith ◽  
M. E. Hearfield
Keyword(s):  
Initial Density ◽  
Early Spring ◽  
Late Winter ◽  
Trichosurus Vulpecula ◽  
Radio Tracking ◽  
Dispersal Behaviour ◽  
Long Distance ◽  
Control Operation ◽  
Preferred Direction ◽  
One Year

Long-distance movements of juvenile brushtail possums (Trichosurus vulpecula) from three habitats on farmland in Hawke’s Bay, New Zealand, were studied by radio-tracking after a poisoning operation. In the five years after the possum population on the study site had been reduced by 90%, the population recovered to about half its initial density. During that time, about 25% of radio-tagged juveniles dispersed 2 km or more, a maximum of 12·8 km from their natal area, with no significantly preferred direction. A greater proportion of males dispersed than females. All but one of the juveniles dispersing did so before they were one year old, and most made several moves before settling. The bimodal timing of dispersal in summer and late winter–early spring reflected an underlying similar pattern of breeding. A higher proportion of possums dispersed from the low-density pastoral and cropping habitat than from the higher-density habitats of swamp and willows. The dispersal behaviour of juveniles after the control operation differed little from that before, suggesting that dispersal of possums is not strongly influenced by density-dependent factors at the natal site.

scholarly journals Toad on the road: Use of roads as dispersal corridors by cane toads (Bufo marinus) at an invasion front in tropical Australia

2006 ◽  
Vol 133 (1) ◽  
pp. 88-94 ◽  
Author(s):  
Gregory P. Brown ◽  
Benjamin L. Phillips ◽  
Jonathan K. Webb ◽  
Richard Shine
Keyword(s):  
Bufo Marinus ◽  
Invasion Front ◽  
The Road ◽  
Tropical Australia ◽  
Dispersal Corridors ◽  
On The Road

scholarly journals Increased rates of dispersal of free-ranging cane toads (Rhinella marina) during their global invasion

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Richard Shine ◽  
Ross A. Alford ◽  
Ryan Blennerhasset ◽  
Gregory P. Brown ◽  
Jayna L. DeVore ◽  
...  
Keyword(s):  
French Guiana ◽  
Native Range ◽  
Rhinella Marina ◽  
Range Edge ◽  
Population Spread ◽  
Eastern Australia ◽  
Tropical Australia ◽  
Free Ranging ◽  
Global Invasion ◽  
Daily Changes

AbstractInvasions often accelerate through time, as dispersal-enhancing traits accumulate at the expanding range edge. How does the dispersal behaviour of individual organisms shift to increase rates of population spread? We collate data from 44 radio-tracking studies (in total, of 650 animals) of cane toads (Rhinella marina) to quantify distances moved per day, and the frequency of displacement in their native range (French Guiana) and two invaded areas (Hawai’i and Australia). We show that toads in their native-range, Hawai’i and eastern Australia are relatively sedentary, while toads dispersing across tropical Australia increased their daily distances travelled from 20 to 200 m per day. That increase reflects an increasing propensity to change diurnal retreat sites every day, as well as to move further during each nocturnal displacement. Daily changes in retreat site evolved earlier than did changes in distances moved per night, indicating a breakdown in philopatry before other movement behaviours were optimised to maximise dispersal.

scholarly journals The accelerating anuran: evolution of locomotor performance in cane toads ( Rhinella marina , Bufonidae) at an invasion front

2020 ◽  
Vol 287 (1938) ◽  
pp. 20201964 ◽  
Author(s):  
Cameron M. Hudson ◽  
Marta Vidal-García ◽  
Trevor G. Murray ◽  
Richard Shine
Keyword(s):  
Morphological Traits ◽  
High Speed ◽  
Morphological Changes ◽  
Locomotor Performance ◽  
Rhinella Marina ◽  
Invasion Front ◽  
In Captivity ◽  
Tropical Australia ◽  
Range Core ◽  
Locomotor Ability

As is common in biological invasions, the rate at which cane toads ( Rhinella marina ) have spread across tropical Australia has accelerated through time. Individuals at the invasion front travel further than range-core conspecifics and exhibit distinctive morphologies that may facilitate rapid dispersal. However, the links between these morphological changes and locomotor performance have not been clearly documented. We used raceway trials and high-speed videography to document locomotor traits (e.g. hop distances, heights, velocities, and angles of take-off and landing) of toads from range-core and invasion-front populations. Locomotor performance varied geographically, and this variation in performance was linked to morphological features that have evolved during the toads' Australian invasion. Geographical variation in morphology and locomotor ability was evident not only in wild-caught animals, but also in individuals that had been raised under standardized conditions in captivity. Our data thus support the hypothesis that the cane toad's invasion across Australia has generated rapid evolutionary shifts in dispersal-relevant performance traits, and that these differences in performance are linked to concurrent shifts in morphological traits.

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