scholarly journals Raised by aliens: constant exposure to an invasive predator triggers morphological but not behavioural plasticity in a threatened species tadpoles

2021 ◽  
Author(s):  
Andrea Melotto ◽  
Gentile Francesco Ficetola ◽  
Roberta Pennati ◽  
Nicoletta Ancona ◽  
Raoul Manenti
Keyword(s):  
Phenotypic Plasticity ◽  
Native Species ◽  
Procambarus Clarkii ◽  
Muscle Size ◽  
Behavioural Plasticity ◽  
The Novel ◽  
Population Declines ◽  
Selective Pressures ◽  
Invasive Predators ◽  
Behavioural Tests

AbstractDuring biotic invasions, native communities are abruptly exposed to novel and often severe selective pressures. The lack of common evolutionary history with invasive predators can hamper the expression of effective anti-predator responses in native prey, potentially accelerating population declines. Nonetheless, rapid adaptation and phenotypic plasticity may allow native species to cope with the new ecological pressures. We tested the hypothesis that phenotypic plasticity is fostered when facing invasive species and evaluated whether plasticity offers a pool of variability that might help the fixation of adaptive phenotypes. We assessed behavioural and morphological trait variation in tadpoles of the Italian agile frog (Rana latastei) in response to the invasive crayfish predator, Procambarus clarkii, by rearing tadpoles under different predation-risk regimes: non-lethal crayfish presence and crayfish absence. After two-month rearing, crayfish-exposed tadpoles showed a plastic shift in their body shape and increased tail muscle size, while behavioural tests showed no effect of crayfish exposure on tadpole behaviour. Furthermore, multivariate analyses revealed weak divergence in morphology between invaded and uninvaded populations, while plasticity levels were similar between invaded and uninvaded populations. Even if tadpoles displayed multiple plastic responses to the novel predator, none of these shifts underwent fixation after crayfish arrival (10–15 years). Overall, these findings highlight that native prey can finely tune their responses to invasive predators through plasticity, but the adaptive value of these responses in whitstanding the novel selective pressures, and the long-term consequences they can entail remain to be ascertained.

scholarly journals Impacts of a Non-indigenous Ecosystem Engineer, the American Beaver (Castor canadensis), in a Biodiversity Hotspot

2021 ◽  
Vol 2 ◽  
Author(s):  
Jonathan Q. Richmond ◽  
Camm C. Swift ◽  
Thomas A. Wake ◽  
Cheryl S. Brehme ◽  
Kristine L. Preston ◽  
...  
Keyword(s):  
Native Species ◽  
Ecosystem Engineer ◽  
Castor Canadensis ◽  
Trophic Dynamics ◽  
The Novel ◽  
Historical Survey ◽  
The Past ◽  
Invasive Predators ◽  
Per Capita ◽  
American Beaver

Non-native species having high per capita impacts in invaded communities are those that modulate resource availability and alter disturbance regimes in ways that are biologically incompatible with the native biota. In areas where it has been introduced by humans, American beaver (Castor canadensis) is an iconic example of such species due to its capacity to alter trophic dynamics of entire ecosystems and create new invasional pathways for other non-native species. The species is problematic in several watersheds within the Southern California-Northern Baja California Coast Ecoregion, a recognized hotspot of biodiversity, due to its ability to modify habitat in ways that favor invasive predators and competitors over the region's native species and habitat. Beaver was deliberately introduced across California in the mid-1900s and generally accepted as non-native to the region up to the early 2000s; however, articles promoting the idea that beaver may be a natural resident have gained traction in recent years, due in large part to the species' charismatic nature rather than by presentation of sound evidence. Here, we discuss the problems associated with beaver disturbance and its effects on conserving the region's native fauna and flora. We refute arguments underlying the claim that beaver is native to the region, and review paleontological, zooarchaeological, and historical survey data from renowned field biologists and naturalists over the past ~160 years to show that no evidence exists that beaver arrived by any means other than deliberate human introduction. Managing this ecosystem engineer has potential to reduce the richness and abundance of other non-native species because the novel, engineered habitat now supporting these species would diminish in beaver-occupied watersheds. At the same time, hydrologic functionality would shift toward more natural, ephemeral conditions that favor the regions' native species while suppressing the dominance of the most insidious invaders.

scholarly journals Seasonal and spatial shifts in feral cat predation on native seabirds vs. non-native rats on Mikura Island, Japan

2020 ◽  
Author(s):  
Sarara Azumi ◽  
Yuya Watari ◽  
Nariko Oka ◽  
Tadashi Miyashita
Keyword(s):  
Native Species ◽  
Control Strategies ◽  
Interspecific Interactions ◽  
Rattus Rattus ◽  
Large Body ◽  
Effective Control ◽  
Alternative Prey ◽  
Feral Cat ◽  
Feral Cats ◽  
Invasive Predators

Abstract Understanding how invasive predators impact native species is essential for the development of effective control strategies, especially in insular environments where alternative non-native prey species exist. We examined seasonal and spatial shifts in diet of feral cat Felis silvestris catus focusing on the predation on native streaked shearwaters, Calonectris leucomelas, and introduced rats, Rattus rattus and R. norvegicus, which are alternative prey to shearwaters, on Mikura Island, Japan. Streaked shearwaters breed at low elevations on the island from spring to autumn, whereas rats inhabit the island throughout the year, which makes them an alternative prey when native shearwaters are absent. Fecal analysis revealed that feral cats dramatically shifted their diets from introduced rats in winter to streaked shearwaters in seabird-season in low elevation areas of the island, while cats preyed on rats throughout the year at high altitudes on the island. This finding suggests that feral cats selectively prey on shearwaters. This is probably because of their large body size and less cautious behavior, and because introduced rats sustain the cat population when shearwaters are absent. The number of streaked shearwaters killed was estimated to be 313 individuals per cat per year, which represents an indication of top-down effects of feral cats on streaked shearwaters. Further studies on the demographic parameters and interspecific interactions of the three species are required to enable effective cat management for the conservation of streaked shearwaters on this island.

Effects of geographic isolation on anti-snakes responses in the wall lizard, Podarcis muralis

2012 ◽  
Vol 33 (2) ◽  
pp. 199-206 ◽  
Author(s):  
Jonas Durand ◽  
Arnaud Legrand ◽  
Mélodie Tort ◽  
Alice Thiney ◽  
Radika J. Michniewicz ◽  
...  
Keyword(s):  
Choice Experiment ◽  
Behavioural Plasticity ◽  
The Novel ◽  
Geographic Isolation ◽  
Podarcis Muralis ◽  
Predatory Behaviour ◽  
Snake Species ◽  
Predator Response ◽  
The Cost ◽  
Predatory Pressure

Alteration in anti-predatory behaviour following geographic isolation has been observed in a number of taxa. Such alteration was attributed to the effect of relaxed selection in the novel environment, reinforced by the cost of anti-predatory behaviours. We studied aspects of anti-snake behaviour in 987 adult and juvenile wall lizards Podarcis muralis from two mainland areas (heavy snake predatory pressure) and two islands (low snake predatory pressure), isolated from the mainland 5000 and 7000 years ago. We conducted a scented retreat site choice experiment using the odours of five different snake species (saurophagous, piscivorous or generalist feeder). Mainland lizards avoided shelters scented by saurophagous snakes, but not those scented by non saurophagous snake species. Long isolated lizards (7000 years ago) showed no anti-predator response to any snake, suggesting a total loss of anti-predatory behaviour towards saurophagous snakes. More recently isolated lizards (5000 years ago) however showed anti-snake behaviour towards a former sympatric adder species, and a tendency to avoid the scent of a sympatric generalist feeder snake. There was no difference in the anti-snake responses between adult and juvenile wall lizards from all four sites, suggesting a limited role for experience (behavioural plasticity) in the expression of anti-snake behaviour in wall lizards.

scholarly journals A global threats overview for Numeniini populations: synthesising expert knowledge for a group of declining migratory birds

2017 ◽  
Vol 27 (1) ◽  
pp. 6-34 ◽  
Author(s):  
JAMES W. PEARCE-HIGGINS ◽  
DANIEL J. BROWN ◽  
DAVID J. T. DOUGLAS ◽  
JOSÉ A. ALVES ◽  
MARIAGRAZIA BELLIO ◽  
...  
Keyword(s):  
Climate Change ◽  
Native Species ◽  
Expert Knowledge ◽  
East Asian ◽  
Expert Assessment ◽  
Population Declines ◽  
East Atlantic ◽  
Commercial Development ◽  
Breeding Sites ◽  
Policy Responses

SummaryThe Numeniini is a tribe of 13 wader species (Scolopacidae, Charadriiformes) of which seven are Near Threatened or globally threatened, including two Critically Endangered. To help inform conservation management and policy responses, we present the results of an expert assessment of the threats that members of this taxonomic group face across migratory flyways. Most threats are increasing in intensity, particularly in non-breeding areas, where habitat loss resulting from residential and commercial development, aquaculture, mining, transport, disturbance, problematic invasive species, pollution and climate change were regarded as having the greatest detrimental impact. Fewer threats (mining, disturbance, problematic native species and climate change) were identified as widely affecting breeding areas. Numeniini populations face the greatest number of non-breeding threats in the East Asian-Australasian Flyway, especially those associated with coastal reclamation; related threats were also identified across the Central and Atlantic Americas, and East Atlantic flyways. Threats on the breeding grounds were greatest in Central and Atlantic Americas, East Atlantic and West Asian flyways. Three priority actions were associated with monitoring and research: to monitor breeding population trends (which for species breeding in remote areas may best be achieved through surveys at key non-breeding sites), to deploy tracking technologies to identify migratory connectivity, and to monitor land-cover change across breeding and non-breeding areas. Two priority actions were focused on conservation and policy responses: to identify and effectively protect key non-breeding sites across all flyways (particularly in the East Asian- Australasian Flyway), and to implement successful conservation interventions at a sufficient scale across human-dominated landscapes for species’ recovery to be achieved. If implemented urgently, these measures in combination have the potential to alter the current population declines of many Numeniini species and provide a template for the conservation of other groups of threatened species.

scholarly journals Population growth estimates of a threatened seabird indicate necessity for additional management following invasive predator eradications

2020 ◽  
Author(s):  
Johannes Fischer ◽  
GA Taylor ◽  
R Cole ◽  
I Debski ◽  
DP Armstrong ◽  
...  
Keyword(s):  
Population Growth ◽  
Native Species ◽  
Linear Models ◽  
Monitoring Methods ◽  
Apparent Lack ◽  
Zoological Society ◽  
Invasive Predators ◽  
Invasive Predator ◽  
Rate Of Increase ◽  
Log Linear

© 2019 The Zoological Society of London The eradication of invasive predators from islands is a successful technique to safeguard seabird populations, but adequate post-eradication monitoring of native species is often lacking. The Whenua Hou Diving Petrel (Pelecanoides whenuahouensis; WHDP) is a recently-described and ‘Critically Endangered’ seabird, restricted to Codfish Island (Whenua Hou), New Zealand. Invasive predators, considered the major threat to WHDP, were eradicated on Codfish Island in 2000. However, estimates of WHDP population size and trends remain unknown, hindering assessments of the success of the eradications. We collated intermittent burrow counts (n = 20 seasons) conducted between 1978 and 2018. To estimate the population growth rate (λ) before and after predator eradications, we used log-linear models in a Bayesian hierarchical framework while retrospectively accounting for differences in detection probabilities among burrow counts, due to differences in effort, marking and timing. The number of WHDP burrows was estimated at 40 (36–46) in 1978 and 100 (97–104) in 2018. The pre-eradication λ was estimated at 1.023 (0.959–1.088), while the post-eradications λ was estimated at 1.017 (1.006–1.029). The WHDP population appears to be increasing, yet the rate of increase is low compared to other Procellariiformes following predator eradications. The comparatively low post-eradication λ, combined with an apparent lack of change between pre- and post-eradication λ, indicates that additional threats might be limiting WHDP population growth and that further conservation management is required. The continuation of affordable and simple, albeit imperfect, monitoring methods with retrospective corrections facilitated the assessment of invasive predator eradications outcomes and should guide future management decisions. An abstract in Te Reo Māori (the Māori language) can be found in Appendix S1.

scholarly journals Human influences on antipredator behaviour in Darwin’s finches

2019 ◽  
Author(s):  
Kiyoko M. Gotanda
Keyword(s):  
Urban Areas ◽  
Antipredator Behaviour ◽  
Human Populations ◽  
Urban Populations ◽  
Darwin's Finches ◽  
Selective Pressures ◽  
Invasive Predators ◽  
Darwin’S Finches ◽  
History Of ◽  
Predator Eradication

Abstract1) Humans exert dramatic influences upon the environment, creating novel selective pressures to which organisms must adapt. On the Galapagos, humans have established a permanent presence and have altered selective pressures through influences such as invasive predators and urbanization, affecting iconic species such as Darwin’s finches.2) Here, I ask two key questions: (i) does antipredator behaviour (e.g. FID) change depending on whether invasive predators are historically absent, present, or eradicated? and (ii) to what degree does urbanization affect antipredator behaviour? This study is one of the first to quantify antipredator behaviour in endemic species after the eradication of invasive predators. This will help to understand the consequences of invasive predator eradication and inform conservation measures.3) I quantified flight initiation distance (FID), an antipredator behaviour, in Darwin’s finches, across multiple islands in the Galapagos that varied in the presence, absence, or successful eradication of invasive predators. On islands with human populations, I quantified FID in urban and non-urban populations of finches.4) FID was higher on islands with invasive predators compared to islands with no predators. On islands from which invasive predators were eradicated ∼11 years previously, FID was also higher than on islands with no invasive predators. Within islands that had both urban and non-urban populations of finches, FID was lower in urban finch populations, but only above a threshold human population size. FID in larger urban areas on islands with invasive predators was similar to or lower than FID on islands with no history of invasive predators.5) Overall, these results suggest that invasive predators can have a lasting effect on antipredator behaviour, even after eradication. Furthermore, the effect of urbanization can strongly oppose the effect of invasive predators, reducing antipredator behaviour to levels lower than found on pristine islands with no human influences. These results improve our understanding of human influences on antipredator behaviour which can help inform future conservation and management efforts on islands.

scholarly journals Quantitative Assessment of Handedness and Cerebral Lateralization

2021 ◽  
Vol 2 (1) ◽  
pp. 6-22
Author(s):  
Beauty Das ◽  
Jed Meltzer ◽  
Blair Armstrong
Keyword(s):  
Performance Measures ◽  
Continuous Variable ◽  
Accurate Estimate ◽  
Brain Lateralization ◽  
The Novel ◽  
Cerebral Lateralization ◽  
Left Handed ◽  
Valid Assessment ◽  
Behavioural Tests ◽  
The Relationship

  Handedness is the most studied human asymmetry due to its connection to various lateralized behaviours and hence many studies have focused on developing a valid assessment. One of the most popular is the Edinburgh Handedness Inventory (EHI), however, its psychometric properties have been questioned and due to its complex response format, various modified versions of EHI are in use. One of them is a 7-item questionnaire produced by Dragovic and Milenkovic (2013), which seeks to reduce a potentially continuous variable to a categorical one by clearly classifying people as right- or left- handed. The purpose of this study was to develop a questionnaire to more accurately quantify mixed-handedness as a continuous variable, and to investigate the correlation between Dragovic’s modified 7-item EHI, new items created for this study, and three performance measures (grooved pegboard, finger-tapping and grip strength/dynamometer). A total of 113 self-reported right-, left- and mixed-handed participants were randomly recruited to complete the questionnaire and behavioural measures. The questionnaire data was submitted to exploratory factor analysis and resulting factor scores were examined for correlations with behavioural tests. Compared to the modified EHI, the questionnaire showed a more continuous grading of handedness. Moreover, the degree of handedness on the questionnaire showed a stronger correlation with all the performance measures than the performance measures had amongst themselves. These findings show that the novel questionnaire with modern-day items can provide an accurate estimate of the degree of mixed-handedness in both right- and left-handed individuals. Future studies should examine these measures on a larger sample of left-handed and ambidextrous people, who tend to be more variable than right-handers in their usage. The questionnaire can also be suitable for studying the relationship between variable handedness and other aspects of brain lateralization.

scholarly journals Population Ecology and Genetic Diversity of the Invasive Alien Species Procambarus clarkii in Lake Trasimeno (Italy)

Biology ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1059
Author(s):  
Ambrosius Josef Martin Dörr ◽  
Melissa Scoparo ◽  
Irene Cardinali ◽  
Gianandrea La Porta ◽  
Barbara Caldaroni ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Alien Species ◽  
Population Ecology ◽  
Native Species ◽  
Invasive Alien Species ◽  
Procambarus Clarkii ◽  
Central Italy ◽  
Monitoring Program ◽  
Mitochondrial Haplotypes ◽  
Management Plans

The deliberate or accidental introduction of invasive alien species (IAS) causes negative ecological and economic impacts altering ecosystem processes, imperiling native species and causing damage to human endeavors. A monthly monitoring program was performed in Lake Trasimeno (Central Italy) from July 2018 to July 2019 in order to provide an upgrade of the population ecology of Procambarus clarkii and to assess the genetic diversity by analyzing the relationships among mitochondrial DNA diversity. Our results confirmed that P. clarkii is well acclimatized in the lake, revealing a stable population structure favored by the resources and conditions typical of this ecosystem, which seem to be optimal for the maintenance of the species. Four distinct mitochondrial haplotypes were detected, but one of them was clearly overrepresented (76%), suggesting that a single predominant introduction event may have occurred in this area, likely followed by secondary events. The identification of the typical genetic variants provides a better understanding of the evolutionary scenarios of P. clarkii in this biotope and it can be helpful in management plans concerning the expanding populations of this invasive alien species.

scholarly journals Whole genome resequencing data enables a targeted SNP panel for conservation and aquaculture of Oreochromis cichlid fishes

2021 ◽  
Author(s):  
Adam Ciezarek ◽  
Antonia Ford ◽  
Graham Etherington ◽  
Kasozi Nasser ◽  
Milan Malinsky ◽  
...  
Keyword(s):  
Native Species ◽  
Cichlid Fish ◽  
Snp Markers ◽  
Whole Genome ◽  
The Novel ◽  
Genome Resequencing ◽  
Genome Wide ◽  
In The Wild ◽  
Snp Panel ◽  
Whole Genome Resequencing

Cichlid fish of the genus Oreochromis form the basis of the global tilapia aquaculture and fisheries industry. Non-native farmed tilapia populations are known to be widely distributed across Africa and to hybridize with native Oreochromis species. However, many species are difficult to distinguish morphologically, hampering attempts to maintain good quality farmed strains or to identify pure populations of native species. Here, we describe the development of a single nucleotide polymorphism (SNP) genotyping panel from whole-genome resequencing data that enables targeted species identification in Tanzania. We demonstrate that an optimized panel of 96 genome-wide SNPs based on FST outliers performs comparably to whole genome resequencing in distinguishing species and identifying hybrids. We also show this panel outperforms microsatellite-based and phenotype-based classification methods. Case studies indicate several locations where introduced aquaculture species have become established in the wild, threatening native Oreochromis species. The novel SNP markers identified here represent an important resource for assessing broodstock purity and helping to conserve unique endemic biodiversity, and in addition potentially for assessing broodstock purity in hatcheries.

scholarly journals Nests in the cities: adaptive and non-adaptive phenotypic plasticity and convergence in an urban bird

2020 ◽  
Vol 287 (1941) ◽  
pp. 20202122
Author(s):  
Samuel A. Bressler ◽  
Eleanor S. Diamant ◽  
Morgan W. Tingley ◽  
Pamela J. Yeh
Keyword(s):  
Phenotypic Plasticity ◽  
Los Angeles ◽  
San Diego ◽  
Critical Role ◽  
Urban Ecosystems ◽  
Urban Environments ◽  
Behavioural Plasticity ◽  
Nesting Biology ◽  
Urban Populations ◽  
Rapid Responses

Phenotypic plasticity plays a critical role in adaptation to novel environments. Behavioural plasticity enables more rapid responses to unfamiliar conditions than evolution by natural selection. Urban ecosystems are one such novel environment in which behavioural plasticity has been documented. However, whether such plasticity is adaptive, and if plasticity is convergent among urban populations, is poorly understood. We studied the nesting biology of an ‘urban-adapter’ species, the dark-eyed junco ( Junco hyemalis ), to understand the role of plasticity in adapting to city life. We examined (i) whether novel nesting behaviours are adaptive, (ii) whether pairs modify nest characteristics in response to prior outcomes, and (iii) whether two urban populations exhibit similar nesting behaviour. We monitored 170 junco nests in urban Los Angeles and compared our results with prior research on 579 nests from urban San Diego. We found that nests placed in ecologically novel locations (off-ground and on artificial surfaces) increased fitness, and that pairs practiced informed re-nesting in site selection. The Los Angeles population more frequently nested off-ground than the San Diego population and exhibited a higher success rate. Our findings suggest that plasticity facilitates adaptation to urban environments, and that the drivers behind novel nesting behaviours are complex and multifaceted.

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