scholarly journals Evolution of defense and herbivory in introduced plants—Testing enemy release using a known source population, herbivore trials, and time since introduction

2020 ◽  
Vol 10 (12) ◽  
pp. 5451-5463
Author(s):  
Claire R. Brandenburger ◽  
Martin Kim ◽  
Eve Slavich ◽  
Floret L. Meredith ◽  
Juha‐Pekka Salminen ◽  
...  
Keyword(s):  
Enemy Release ◽  
Source Population ◽  
Introduced Plants ◽  
Time Since Introduction

The Horseshoe whip snake (Hemorrhois hippocrepis) on Ibiza: predator release in an invasive population

2020 ◽  
pp. 1-6
Author(s):  
Elba Montes ◽  
Mónica Feriche ◽  
Esmeralda Alaminos ◽  
Juan Manuel Pleguezuelos
Keyword(s):  
Lower Incidence ◽  
Enemy Release Hypothesis ◽  
Invasion Success ◽  
Enemy Release ◽  
Source Population ◽  
Invasive Population ◽  
Breakage Rate ◽  
Snake Predators ◽  
Whip Snake ◽  
Predator Release

Abstract The key to fighting a biological invasion may lie in understanding every variable that can explain its success. The Enemy Release Hypothesis (ERH) states that when an invader arrives to a new environment, the absence of its common enemies (predators, parasites and competitors) facilitates the invasion success. The Horseshoe whip snake (Hemorrhois hippocrepis) has been recently introduced from the Iberian Peninsula to the island of Ibiza, and it is currently threatening the only endemic vertebrate, the Ibiza wall lizard (Podarcis pityusensis). We hypothesized that the snake invasion success is caused by the absence of natural predators, and we checked the ERH by relating the tail breakage rate to predation pressure. The invasive population showed a much lower incidence of tail breakage than the source population, which is in agreement with the almost absence of snake predators among the Ibizan reduced and naïve native vertebrate community. These results confirm the ERH, and support the prolongation of invasive snake trapping campaigns.

scholarly journals Rapid evolution of leaf physiology in an introduced beach daisy

2019 ◽  
Vol 286 (1909) ◽  
pp. 20191103 ◽  
Author(s):  
Claire R. Brandenburger ◽  
Julia Cooke ◽  
William B. Sherwin ◽  
Angela T. Moles
Keyword(s):  
Introduced Species ◽  
Photosynthetic Rate ◽  
Nitrogen Use Efficiency ◽  
Rapid Evolution ◽  
Sandy Beaches ◽  
Source Population ◽  
Nitrogen Use ◽  
Introduced Plants ◽  
Introduced Range ◽  
Use Efficiency

Photosynthesis is a key biological process. However, we know little about whether plants change their photosynthetic strategy when introduced to a new range. We located the most likely source population for the South African beach daisy Arctotheca populifolia introduced to Australia in the 1930s, and ran a common-garden experiment measuring 10 physiological and morphological leaf traits associated with photosynthesis. Based on predictions from theory, and higher rainfall in the introduced range, we hypothesized that introduced plants would have a (i) higher photosynthetic rate, (ii) lower water-use efficiency (WUE) and (iii) higher nitrogen-use efficiency. However, we found that introduced A. populifolia had a lower photosynthetic rate, higher WUE and lower nitrogen-use efficiency than did plants from Arniston, South Africa. Subsequent site visits suggested that plants in Arniston may be able to access moisture on a rocky shelf, while introduced plants grow on sandy beaches where water can quickly dissipate. Our unexpected findings highlight that: (1) it is important to compare introduced species to their source population for an accurate assessment of evolutionary change; (2) rainfall is not always a suitable proxy for water availability and (3) introduced species often undergo evolutionary changes, but without detailed ecological information we may not be able to accurately predict the direction of these changes.

scholarly journals Rapid reshaping: the evolution of morphological changes in an introduced beach daisy

2019 ◽  
Vol 286 (1897) ◽  
pp. 20181713 ◽  
Author(s):  
Claire R. Brandenburger ◽  
William B. Sherwin ◽  
Stephanie M. Creer ◽  
Robert Buitenwerf ◽  
Alistair G. B. Poore ◽  
...  
Keyword(s):  
Introduced Species ◽  
Morphological Changes ◽  
Leaf Shape ◽  
Rapid Evolution ◽  
Source Population ◽  
Total Biomass ◽  
Introduced Plants ◽  
Introduced Populations ◽  
Introduced Range ◽  
Eastern Australia

Thousands of species have been introduced to new ranges worldwide. These introductions provide opportunities for researchers to study evolutionary changes in form and function in response to new environmental conditions. However, almost all previous studies of morphological change in introduced species have compared introduced populations to populations from across the species' native range, so variation within native ranges probably confounds estimates of evolutionary change. In this study, we used microsatellites to locate the source population for the beach daisy Arctotheca populifolia that had been introduced to eastern Australia. We then compared four introduced populations from Australia with their original South African source population in a common-environment experiment. Despite being separated for less than 100 years, source and introduced populations of A. populifolia display substantial heritable morphological differences. Contrary to the evolution of increased competitive ability hypothesis, introduced plants were shorter than source plants, and introduced and source plants did not differ in total biomass. Contrary to predictions based on higher rainfall in the introduced range, introduced plants had smaller, thicker leaves than source plants. Finally, while source plants develop lobed adult leaves, introduced plants retain their spathulate juvenile leaf shape into adulthood. These changes indicate that rapid evolution in introduced species happens, but not always in the direction predicted by theory.

Does time since introduction influence enemy release of an invasive weed?

Oecologia ◽  
2013 ◽  
Vol 173 (2) ◽  
pp. 493-506 ◽  
Author(s):  
Kerinne J. Harvey ◽  
David A. Nipperess ◽  
David R. Britton ◽  
Lesley Hughes
Keyword(s):  
Enemy Release ◽  
Invasive Weed ◽  
Time Since Introduction

Investigation of 18 physiologically dormant Australian native species: germination response, environmental correlations and the implications for conservation

2020 ◽  
pp. 1-9
Author(s):  
Justin C. Collette ◽  
Mark K.J. Ooi
Keyword(s):  
Native Species ◽  
Strong Dependence ◽  
Ex Situ ◽  
Source Population ◽  
Seasonal Temperature ◽  
Environmental Correlations ◽  
Rainfall Season ◽  
Germination Response ◽  
Rainfall Seasonality ◽  
Germination Experiments

Abstract For physiologically dormant (PD) species in fire-prone environments, dormancy can be both complex due to the interaction between fire and seasonal cues, and extremely deep due to long intervals between recruitment events. Due to this complexity, there are knowledge gaps particularly surrounding the dormancy depth and cues of long-lived perennial PD species. This can be problematic for both in situ and ex situ species management. We used germination experiments that tested seasonal temperature, smoke, dark and heat for 18 PD shrub species distributed across temperate fire-prone Australia and assessed how germination was correlated with environmental factors associated with their home environments. We found extremely high levels of dormancy, with only eight species germinating above 10% and three species producing no germination at all. Seven of these eight species had quite specific seasonal temperature requirements and/or very strong responses to smoke cues. The maximum germination for each species was positively correlated with the mean temperature of the source population but negatively correlated with rainfall seasonality and driest months. The strong dependence on a smoke cue for some of the study species, along with examples from other studies, provides evidence that an obligate smoke response could be a fire-adapted germination cue. Germination response correlated with rainfall season of the source populations is a pattern which has often been assumed but little comparative data across sites with different rainfall seasonality exists. Further investigation of a broader range of species from different rainfall season environments would help to elucidate this knowledge gap.

Using novel methodologies to support burden of disease estimates

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
T Hald
Keyword(s):  
International Development ◽  
Traditional Approach ◽  
Source Population ◽  
Surveillance Systems ◽  
Data Generation ◽  
Time Data ◽  
African Countries ◽  
Indirect Measure ◽  
True Incidence ◽  
Laboratory Capacity

Abstract A challenge to estimating burden of diarrheal diseases, particularly in LMICs, where laboratory capacity and surveillance systems are limited, is obtaining valid estimates of etiology proportions of cases. A commonly used method is systematic review of studies reporting pathogen isolation in diarrhea cases. However, studies often differ in design, source population, timeframe, and pathogens included, hampering extrapolation to the target population. In a study co-funded by the Bill and Melinda Gates Foundation and the UK Department for International Development, we explore a novel approach for estimating diarrhea etiology proportions in urban and rural populations in four African countries. We analyse sewage samples using short-read next-generation sequencing (NGS) to determine abundance of genes that can be mapped to specific bacterial genera, providing an estimate of the relative abundance of specific pathogens in each sample. In parallel to collecting sewage samples, a questionnaire-based population survey will estimate diarrheal incidence. By combining results, pathogen-specific incidence will be estimated and compared with incidence estimates from the traditional approach. The application NGS to human sewage has great potential for surveillance of foodborne infections, particularly in resource-poor settings where laboratory capacity for bacterial isolation is limited. First, NGS is a one method takes all approach, as it is based on detection of RNA/DNA, a language common across pathogens. Second, it is culture independent, allowing for real-time data generation and standardized sharing. Finally, few samples are needed to survey large populations for several pathogens at the same time. Thus, surveillance based on NGS of sewage may prove to be an indirect measure of incidence. Although it will not provide an estimate for the true incidence in the population, it will increase our understanding of the burden and as such be a proxy and novel way of ranking diseases.

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