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Diversity, Volume 9, Issue 1 (March 2017)

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Editorial

Jump to: Research, Review

Open AccessEditorial Acknowledgement to Reviewers of Diversity in 2016
Diversity 2017, 9(1), 4; doi:10.3390/d9010004
Received: 11 January 2017 / Accepted: 11 January 2017 / Published: 11 January 2017
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Abstract The editors of Diversity would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...] Full article

Research

Jump to: Editorial, Review

Open AccessArticle Environmental Tipping Points for Sperm Motility, Fertilization, and Embryonic Development in the Crown-of-Thorns Starfish
Diversity 2017, 9(1), 10; doi:10.3390/d9010010
Received: 30 November 2016 / Revised: 25 January 2017 / Accepted: 10 February 2017 / Published: 15 February 2017
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Abstract
For broadcast spawning invertebrates such as the crown-of-thorns starfish, early life history stages (from spawning to settlement) may be exposed to a wide range of environmental conditions, and could have a major bearing on reproductive success and population replenishment. Arrested development in response
[...] Read more.
For broadcast spawning invertebrates such as the crown-of-thorns starfish, early life history stages (from spawning to settlement) may be exposed to a wide range of environmental conditions, and could have a major bearing on reproductive success and population replenishment. Arrested development in response to multiple environmental stressors at the earliest stages can be used to define lower and upper limits for normal development. Here, we compared sperm swimming speeds and proportion of motile sperm and rates of fertilization and early development under a range of environmental variables (temperature: 20–36 °C, salinity: 20–34 psu, and pH: 7.4–8.2) to identify environmental tipping points and thresholds for reproductive success. We also tested the effects of water-soluble compounds, derived from eggs, on sperm activity. Our results demonstrate that gametes, fertilization, and embryonic development are robust to a wide range of temperature, salinity, and pH levels that are outside the range found at the geographical limits of adult distribution and can tolerate environmental conditions that exceed expected anomalies as a result of climate change. Water-soluble compounds derived from eggs also enhanced sperm activity, particularly in environmental conditions where sperm motility was initially limited. These findings suggest that fertilization and embryonic development of crown-of-thorns starfish are tolerant to a wide range of environmental conditions, though environmental constraints on recruitment success may occur at later ontogenic stages. Full article
(This article belongs to the Special Issue Biology, Ecology and Management of Crown-of-Thorns Starfish)
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Open AccessArticle Estimating Invasion Success by Non-Native Trees in a National Park Combining WorldView-2 Very High Resolution Satellite Data and Species Distribution Models
Diversity 2017, 9(1), 6; doi:10.3390/d9010006
Received: 14 September 2016 / Revised: 29 December 2016 / Accepted: 10 January 2017 / Published: 18 January 2017
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Abstract
Invasion by non-native tree species is an environmental and societal challenge requiring predictive tools to assess invasion dynamics. The frequent scale mismatch between such tools and on-ground conservation is currently limiting invasion management. This study aimed to reduce these scale mismatches, assess the
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Invasion by non-native tree species is an environmental and societal challenge requiring predictive tools to assess invasion dynamics. The frequent scale mismatch between such tools and on-ground conservation is currently limiting invasion management. This study aimed to reduce these scale mismatches, assess the success of non-native tree invasion and determine the environmental factors associated to it. A hierarchical scaling approach combining species distribution models (SDMs) and satellite mapping at very high resolution (VHR) was developed to assess invasion by Acacia dealbata in Peneda-Gerês National Park, the only national park in Portugal. SDMs were first used to predict the climatically suitable areas for A. dealdata and satellite mapping with the random-forests classifier was then applied to WorldView-2 very-high resolution imagery to determine whether A. dealdata had actually colonized the predicted areas (invasion success). Environmental attributes (topographic, disturbance and canopy-related) differing between invaded and non-invaded vegetated areas were then analyzed. The SDM results indicated that most (67%) of the study area was climatically suitable for A. dealbata invasion. The onset of invasion was documented to 1905 and satellite mapping highlighted that 12.6% of study area was colonized. However, this species had only colonized 62.5% of the maximum potential range, although was registered within 55.6% of grid cells that were considerable unsuitable. Across these areas, the specific success rate of invasion was mostly below 40%, indicating that A. dealbata invasion was not dominant and effective management may still be possible. Environmental attributes related to topography (slope), canopy (normalized difference vegetation index (ndvi), land surface albedo) and disturbance (historical burnt area) differed between invaded and non-invaded vegetated area, suggesting that landscape attributes may alter at specific locations with Acacia invasion. Fine-scale spatial-explicit estimation of invasion success combining SDM predictions with VHR invasion mapping allowed the scale mismatch between predictions of invasion dynamics and on-ground conservation decision making for invasion management to be reduced. Locations with greater potential to suppress invasions could also be defined. Uncertainty in the invasion mapping needs to be accounted for in the interpretation of the results. Full article
(This article belongs to the Special Issue Biodiversity Study by Remote Sensing)
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Open AccessArticle Turnover Dynamics of Breeding Land Birds on Islands: is Island Biogeographic Theory ‘True but Trivial’ over Decadal Time-Scales?
Diversity 2017, 9(1), 3; doi:10.3390/d9010003
Received: 28 October 2016 / Revised: 21 December 2016 / Accepted: 28 December 2016 / Published: 11 January 2017
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Abstract
The theory of island biogeography has revolutionised the study of island biology stimulating considerable debate and leading to the development of new advances in related areas. One criticism of the theory is that it is ‘true but trivial’, i.e., on the basis of
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The theory of island biogeography has revolutionised the study of island biology stimulating considerable debate and leading to the development of new advances in related areas. One criticism of the theory is that it is ‘true but trivial’, i.e., on the basis of analyses of annual turnovers of organisms on islands, it has been posited that stochastic turnover mainly comprises rare species, or repeated immigrations and extinctions thereof, and thereby contribute little to the overall ecological dynamics. Here, both the absolute and relative turnover of breeding land birds are analysed for populations on Skokholm, Wales, over census intervals of 1, 3, 6, 12, and 24 years. As expected, over short census intervals (≤6 years), much of the turnover comprised repeated colonisations and extinctions of rare species. However, at longer intervals (12 and 24 years), a sizeable minority of species (11% of the total recorded) showed evidence of colonisation and/or extinction events despite sizeable populations (some upwards of 50 pairs). These results suggest that a longer-term view is required to take into account turnover involving more common species. Full article
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Open AccessArticle Tracking the Recovery of Freshwater Mussel Diversity in Ontario Rivers: Evaluation of a Quadrat-Based Monitoring Protocol
Diversity 2017, 9(1), 5; doi:10.3390/d9010005
Received: 11 November 2016 / Revised: 15 December 2016 / Accepted: 6 January 2017 / Published: 13 January 2017
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Abstract
Watershed inventories and population monitoring are essential components of efforts to conserve and recover freshwater mussel diversity in Canada. We used two datasets to assess the efficacy of a quadrat-based sampling protocol for: (1) detecting mussel species at risk; (2) characterizing species composition;
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Watershed inventories and population monitoring are essential components of efforts to conserve and recover freshwater mussel diversity in Canada. We used two datasets to assess the efficacy of a quadrat-based sampling protocol for: (1) detecting mussel species at risk; (2) characterizing species composition; (3) providing accurate estimates of abundance; and (4) detecting changes in density. The protocol is based on a systematic design (with random starts) that samples 20% of monitoring sites with visual-tactile surface searches and excavation of 1 m2 quadrats. The first dataset included 40 sampling sites in five Ontario rivers, and the second dataset consisted of complete census sampling at two 375 m2 sites that represented contrasting mussel assemblages. Our results show that the protocol can be expected to detect the majority of species present at a site and provide accurate and precise estimates of total mussel density. Excavation was essential for detection of small individuals and to accurately estimate abundance. However, the protocol was of limited usefulness for reliable detection of most species at risk. Furthermore, imprecise density estimates precluded detection of all but the most extreme changes in density of most individual species. Meeting monitoring objectives will require either substantially greater sampling effort under the current protocol, or a fundamental revision of the sampling approach. Full article
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Open AccessArticle Selective Feeding and Microalgal Consumption Rates by Crown-Of-Thorns Seastar (Acanthaster cf. solaris) Larvae
Diversity 2017, 9(1), 8; doi:10.3390/d9010008
Received: 24 November 2016 / Revised: 25 January 2017 / Accepted: 30 January 2017 / Published: 7 February 2017
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Abstract
Outbreaks of the crown-of-thorns seastar (CoTS) represent a major cause of coral loss on the Great Barrier Reef. Outbreaks can be explained by enhanced larval survival supported by higher phytoplankton availability after flood events, yet little is known about CoTS larvae feeding behaviour,
[...] Read more.
Outbreaks of the crown-of-thorns seastar (CoTS) represent a major cause of coral loss on the Great Barrier Reef. Outbreaks can be explained by enhanced larval survival supported by higher phytoplankton availability after flood events, yet little is known about CoTS larvae feeding behaviour, in particular their potential for selective feeding. Here, single- and mixed-species feeding experiment were conducted on CoTS larvae using five algae (Phaeodactylum tricornutum, Pavlova lutheri, Tisochrysis lutea, Dunaliella sp. and Chaetoceros sp.) and two algal concentrations (1000 and 2500 algae·mL−1). Cell counts using flow-cytometry at the beginning and end of each incubation experiment allowed us to calculate the filtration and ingestion rates of each species by CoTS larvae. In line with previous studies, CoTS larvae ingested more algae when the initial algal concentration was higher. We found evidence for the selective ingestion of some species (Chaetoceros sp., Dunaliella sp.) over others (P. lutheri, P. tricornutum). The preferred algal species had the highest energy content, suggesting that CoTS selectively ingested the most energetic algae. Ultimately, combining these results with spatio-temporal patterns in phytoplankton communities will help elucidate the role of larval feeding behaviour in determining the frequency and magnitude of CoTS outbreaks. Full article
(This article belongs to the Special Issue Biology, Ecology and Management of Crown-of-Thorns Starfish)
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Open AccessArticle Modelling Growth of Juvenile Crown-of-Thorns Starfish on the Northern Great Barrier Reef
Diversity 2017, 9(1), 1; doi:10.3390/d9010001
Received: 18 November 2016 / Revised: 23 December 2016 / Accepted: 26 December 2016 / Published: 29 December 2016
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Abstract
The corallivorous crown-of-thorns starfish (Acanthaster spp.) is a major cause of coral mortality on Indo-Pacific reefs. Despite considerable research into the biology of crown-of-thorns starfish, our understanding of the early post-settlement life stage has been hindered by the small size and cryptic
[...] Read more.
The corallivorous crown-of-thorns starfish (Acanthaster spp.) is a major cause of coral mortality on Indo-Pacific reefs. Despite considerable research into the biology of crown-of-thorns starfish, our understanding of the early post-settlement life stage has been hindered by the small size and cryptic nature of recently settled individuals. Most growth rates are derived from either laboratory studies or field studies conducted in Fiji and Japan. The Great Barrier Reef (GBR) is currently experiencing its fourth recorded outbreak and population models to inform the progression of outbreaks lack critical growth rates of early life history stages. High numbers of 0+ year juveniles (n = 3532) were measured during extensive surveys of 64 reefs on the northern GBR between May and December 2015. An exponential growth model was fitted to the size measurement data to estimate monthly ranges of growth rates for 0+ year juveniles. Estimated growth rates varied considerably and increased with age (e.g., 0.028–0.041 mm·day−1 for one-month-old juveniles versus 0.108–0.216 mm·day−1 for twelve-month-old juveniles). This pioneering study of 0+ year juveniles on the GBR will inform population models and form the basis for more rigorous ongoing research to understand the fate of newly settled Acanthaster spp. Full article
(This article belongs to the Special Issue Biology, Ecology and Management of Crown-of-Thorns Starfish)
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Open AccessCommunication Larval Survivorship and Settlement of Crown-of-Thorns Starfish (Acanthaster cf. solaris) at Varying Algal Cell Densities
Diversity 2017, 9(1), 2; doi:10.3390/d9010002
Received: 14 November 2016 / Revised: 2 January 2017 / Accepted: 4 January 2017 / Published: 10 January 2017
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Abstract
The dispersal potential of crown-of-thorns starfish (CoTS) larvae is important in understanding both the initiation and spread of population outbreaks, and is fundamentally dependent upon how long larvae can persist while still retaining the capacity to settle. This study quantified variation in larval
[...] Read more.
The dispersal potential of crown-of-thorns starfish (CoTS) larvae is important in understanding both the initiation and spread of population outbreaks, and is fundamentally dependent upon how long larvae can persist while still retaining the capacity to settle. This study quantified variation in larval survivorship and settlement rates for CoTS maintained at three different densities of a single-celled flagellate phytoplankton, Proteomonas sulcata (1 × 103, 1 × 104, and 1 × 105 cells/mL). Based on the larval starvation hypothesis, we expected that low to moderate levels of phytoplankton prey would significantly constrain both survival and settlement. CoTS larvae were successfully maintained for up to 50 days post-fertilization, but larval survival differed significantly between treatments. Survival was greatest at intermediate food levels (1 × 104 cells/mL), and lowest at high (1 × 105 cells/mL) food levels. Rates of settlement were also highest at intermediate food levels and peaked at 22 days post-fertilization. Peak settlement was delayed at low food levels, probably reflective of delayed development, but there was no evidence of accelerated development at high chlorophyll concentrations. CoTS larvae were recorded to settle 17–43 days post-fertilization, but under optimum conditions with intermediate algal cell densities, peak settlement occurred at 22 days post-fertilization. Natural fluctuations in nutrient concentrations and food availability may affect the number of CoTS that effectively settle, but seem unlikely to influence dispersal dynamics. Full article
(This article belongs to the Special Issue Biology, Ecology and Management of Crown-of-Thorns Starfish)
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Open AccessArticle Variation in Incidence and Severity of Injuries among Crown-of-Thorns Starfish (Acanthaster cf. solaris) on Australia’s Great Barrier Reef
Diversity 2017, 9(1), 12; doi:10.3390/d9010012
Received: 8 December 2016 / Accepted: 10 February 2017 / Published: 21 February 2017
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Abstract
Despite the presence of numerous sharp poisonous spines, adult crown-of-thorns starfish (CoTS) are vulnerable to predation, though the importance and rates of predation are generally unknown. This study explores variation in the incidence and severity of injuries for Acanthaster cf. solaris from Australia’s
[...] Read more.
Despite the presence of numerous sharp poisonous spines, adult crown-of-thorns starfish (CoTS) are vulnerable to predation, though the importance and rates of predation are generally unknown. This study explores variation in the incidence and severity of injuries for Acanthaster cf. solaris from Australia’s Great Barrier Reef. The major cause of such injuries is presumed to be sub-lethal predation such that the incidence of injuries may provide a proxy for overall predation and mortality rates. A total of 3846 Acanthaster cf. solaris were sampled across 19 reefs, of which 1955 (50.83%) were injured. Both the incidence and severity of injuries decreased with increasing body size. For small CoTS (<125 mm total diameter) >60% of individuals had injuries, and a mean 20.7% of arms (±2.9 SE) were affected. By comparison, <30% of large (>450 mm total diameter) CoTS had injuries, and, among those, only 8.3% of arms (±1.7 SE) were injured. The incidence of injuries varied greatly among reefs but was unaffected by the regulations of local fisheries. Full article
(This article belongs to the Special Issue Biology, Ecology and Management of Crown-of-Thorns Starfish)
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Open AccessArticle The Effects of Salinity and pH on Fertilization, Early Development, and Hatching in the Crown-of-Thorns Seastar
Diversity 2017, 9(1), 13; doi:10.3390/d9010013
Received: 2 December 2016 / Revised: 4 February 2017 / Accepted: 10 February 2017 / Published: 22 February 2017
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Abstract
Understanding the influence of environmental factors on the development and dispersal of crown-of-thorns seastars is critical to predicting when and where outbreaks of these coral-eating seastars will occur. Outbreaks of crown-of-thorns seastars are hypothesized to be driven by terrestrial runoff events that increase
[...] Read more.
Understanding the influence of environmental factors on the development and dispersal of crown-of-thorns seastars is critical to predicting when and where outbreaks of these coral-eating seastars will occur. Outbreaks of crown-of-thorns seastars are hypothesized to be driven by terrestrial runoff events that increase nutrients and the phytoplankton food for the larvae. In addition to increasing larval food supply, terrestrial runoff may also reduce salinity in the waters where seastars develop. We investigated the effects of reduced salinity on the fertilization and early development of seastars. We also tested the interactive effects of reduced salinity and reduced pH on the hatching of crown-of-thorns seastars. Overall, we found that reduced salinity has strong negative effects on fertilization and early development, as shown in other echinoderm species. We also found that reduced salinity delays hatching, but that reduced pH, in isolation or in combination with lower salinity, had no detectable effects on this developmental milestone. Models that assess the positive effects of terrestrial runoff on the development of crown-of-thorns seastars should also consider the strong negative effects of lower salinity on early development including lower levels of fertilization, increased frequency of abnormal development, and delayed time to hatching. Full article
(This article belongs to the Special Issue Biology, Ecology and Management of Crown-of-Thorns Starfish)
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Open AccessArticle Phenotyping, Genotyping, and Selections within Italian Local Landraces of Romanesco Globe Artichoke
Diversity 2017, 9(1), 14; doi:10.3390/d9010014
Received: 25 November 2016 / Revised: 22 February 2017 / Accepted: 23 February 2017 / Published: 1 March 2017
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Abstract
Ten Italian globe artichoke clones belonging to the Romanesco typology were characterized in the western coastal area of Italy (Cerveteri, Rome), using a combination of morphological (UPOV descriptors), biochemical (HPLC analysis), and molecular (AFLP, ISSR, and SSR markers) traits. Significant differences among clones
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Ten Italian globe artichoke clones belonging to the Romanesco typology were characterized in the western coastal area of Italy (Cerveteri, Rome), using a combination of morphological (UPOV descriptors), biochemical (HPLC analysis), and molecular (AFLP, ISSR, and SSR markers) traits. Significant differences among clones were found for many of the quantitative and qualitative morphological traits. Multivariate analyses (Principal Component Analysis) showed that, of the 47 morphological descriptors assessed, four (i.e., plant height, central flower-head weight, earliness, and total flower-head weight) presented a clear grouping of the clones. Biochemical analyses showed that the clones significantly differed in the polyphenolic profiles of the flower-head, with the suggestion that some of these, such as S2, S3, S5, and S18, are more suitable for the fresh market. The clones, clustered by a UPGMA dendrogram based on 393 polymorphic AFLP and ISSR loci, showed that the clones were genetically separated from each other. This highlights the importance of characterizing, evaluating, and conserving autochthonous germplasm for future plant breeding activities. Overall, these studies resulted in the identification of two new clones, selected on the basis of flower-head morphology and earliness. These clones, named Michelangelo and Raffaello, are registered on the Italian National Register of Varieties (DM n. 6135, 3/29/2013 G.U. 91, 18 April 2013). Full article
(This article belongs to the Special Issue Characterization and Preservation of Plant Genetic Diversity)
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Open AccessArticle Interactive Effects of Endogenous and Exogenous Nutrition on Larval Development for Crown-Of-Thorns Starfish
Diversity 2017, 9(1), 15; doi:10.3390/d9010015
Received: 30 November 2016 / Revised: 22 February 2017 / Accepted: 27 February 2017 / Published: 4 March 2017
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Abstract
Outbreaks of crown-of-thorns starfish are often attributed to step-changes in larval survivorship following anomalous increases in nutrients and food availability. However, larval growth and development is also influenced by the nutritional condition of spawning females, such that maternal provisioning may offset limitations imposed
[...] Read more.
Outbreaks of crown-of-thorns starfish are often attributed to step-changes in larval survivorship following anomalous increases in nutrients and food availability. However, larval growth and development is also influenced by the nutritional condition of spawning females, such that maternal provisioning may offset limitations imposed by limited access to exogenous sources of nutrients during the formative stages of larval development. This study examined the individual, additive, and interactive effects of endogenous (maternal diet: Acropora, Porites, mixed, and starved) and exogenous (larval diet: high concentration at 104 cells·mL−1, low concentration at 103 algal cells·mL−1, and starved) nutrition on the survival, growth, morphology, and development of larvae of the crown-of-thorns starfish. Female starfish on Acropora and mixed diet produced bigger oocytes compared to Porites-fed and starved treatments. Using oocyte size as a proxy for maternal provisioning, endogenous reserves in the oocyte had a strong influence on initial larval survival and development. This suggests that maternal reserves can delay the onset of obligate exogenous food acquisition and allow larvae to endure prolonged periods of poor environmental nutritive conditions or starvation. The influence of exogenous nutrition became more prominent in later stages, whereby none of the starved larvae reached the mid-to-late brachiolaria stage 16 days after the onset of the ability to feed. There was no significant difference in the survival, development, and competency of larvae between high and low food treatments. Under low algal food conditions, larvae compensate by increasing the length of ciliated feeding bands in relation to the maximum length and width, which improve food capture and feeding efficiency. However, the effects of endogenous nutrition persisted in the later developmental stages, as larvae from starved females were unable to develop larger feeding structures in response to food-limiting conditions. Phenotypic plasticity influenced by endogenous provisions and in response to exogenous food availability may be an important strategy in boosting the reproductive success of crown-of-thorns starfish, leading to population outbreaks. Full article
(This article belongs to the Special Issue Biology, Ecology and Management of Crown-of-Thorns Starfish)
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Open AccessArticle Microsatellites Reveal Genetic Homogeneity among Outbreak Populations of Crown-of-Thorns Starfish (Acanthaster cf. solaris) on Australia’s Great Barrier Reef
Diversity 2017, 9(1), 16; doi:10.3390/d9010016
Received: 30 November 2016 / Revised: 5 March 2017 / Accepted: 7 March 2017 / Published: 10 March 2017
Cited by 1 | PDF Full-text (804 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Specific patterns in the initiation and spread of reef-wide outbreaks of crown-of-thorns starfish are important, both to understand potential causes (or triggers) of outbreaks and to develop more effective and highly targeted management and containment responses. Using analyses of genetic diversity and structure
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Specific patterns in the initiation and spread of reef-wide outbreaks of crown-of-thorns starfish are important, both to understand potential causes (or triggers) of outbreaks and to develop more effective and highly targeted management and containment responses. Using analyses of genetic diversity and structure (based on 17 microsatellite loci), this study attempted to resolve the specific origin for recent outbreaks of crown-of-thorns on Australia’s Great Barrier Reef (GBR). We assessed the genetic structure amongst 2705 starfish collected from 13 coral reefs in four regions that spanned ~1000 km of the GBR. Our results indicate that populations sampled across the full length of the GBR are genetically homogeneous (G’ST = −0.001; p = 0.948) with no apparent genetic structure between regions. Approximate Bayesian computational analyses suggest that all sampled populations had a common origin and that current outbreaking populations of crown-of-thorns starfish (CoTS) in the Swains are not independent of outbreak populations in the northern GBR. Despite hierarchical sampling and large numbers of CoTS genotyped from individual reefs and regions, limited genetic structure meant we were unable to determine a putative source population for the current outbreak of CoTS on the GBR. The very high genetic homogeneity of sampled populations and limited evidence of inbreeding indicate rapid expansion in population size from multiple, undifferentiated latent populations. Full article
(This article belongs to the Special Issue Biology, Ecology and Management of Crown-of-Thorns Starfish)
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Open AccessFeature PaperArticle Age and Growth of An Outbreaking Acanthaster cf. solaris Population within the Great Barrier Reef
Diversity 2017, 9(1), 18; doi:10.3390/d9010018
Received: 20 December 2016 / Revised: 6 March 2017 / Accepted: 8 March 2017 / Published: 14 March 2017
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Abstract
Despite having been studied for more than 40 years, much about the basic life history of crown-of-thorns starfish (CoTS; Acanthaster spp.) remains poorly understood. Size at age—a key metric of productivity for any animal population—has yet to be clearly defined, primarily due to
[...] Read more.
Despite having been studied for more than 40 years, much about the basic life history of crown-of-thorns starfish (CoTS; Acanthaster spp.) remains poorly understood. Size at age—a key metric of productivity for any animal population—has yet to be clearly defined, primarily due to difficulties in obtaining validated ages and potentially indeterminate growth due to factors such as starvation; within-population variability is entirely unknown. Here we develop age and growth estimates for an outbreaking CoTS population in Australian waters by integrating prior information with data from CoTS collected from multiple outbreaking reefs. Age estimates were made from un-validated band counts of 2038 individual starfish. Results from our three-parameter von Bertalanffy Bayesian hierarchical model show that, under 2013–2014 outbreak conditions, CoTS on the GBR grew to a 349 (326, 380) mm (posterior median (95% uncertainty interval)) total diameter at a 0.54 (0.43, 0.66) intrinsic rate of increase. However, we also found substantial evidence (ΔDIC > 200) for inter-reef variability in both maximum size (SD 38 (19, 76)) and intrinsic rate of increase (SD 0.32 (0.20, 0.49)) within the CoTS outbreak initiation area. These results suggest that CoTS demography can vary widely with reef-scale environmental conditions, supporting location-based mechanisms for CoTS outbreaks generally. These findings should help improve population and metapopulation models of CoTS dynamics and better predict the potential damage they may cause in the future. Full article
(This article belongs to the Special Issue Biology, Ecology and Management of Crown-of-Thorns Starfish)
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Review

Jump to: Editorial, Research

Open AccessReview Potential Population Genetic Consequences of Habitat Fragmentation in Central European Forest Trees and Associated Understorey Species—An Introductory Survey
Diversity 2017, 9(1), 9; doi:10.3390/d9010009
Received: 15 November 2016 / Revised: 20 January 2017 / Accepted: 7 February 2017 / Published: 14 February 2017
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Abstract
Habitat fragmentation threatens the maintenance of genetic diversity of affected populations. Assessment of the risks associated with habitat fragmentation is a big challenge as the change in population genetic diversity is a dynamic process, often acting over long time periods and depending on
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Habitat fragmentation threatens the maintenance of genetic diversity of affected populations. Assessment of the risks associated with habitat fragmentation is a big challenge as the change in population genetic diversity is a dynamic process, often acting over long time periods and depending on various characteristics pertaining to both species (life history traits) and their populations (extrinsic characteristics). With this survey, we provide an introductory overview for persons who have to make or are interested in making predictions about the fate of forest-dwelling plant populations which have recently become fragmented and isolated from their main occurrences. We provide a concise introduction to the field of population genetics focusing on terms, processes and phenomena relevant to the maintenance of genetic diversity and vitality of plant populations. In particular the antagonistic effects of gene flow and random genetic drift are covered. A special chapter is devoted to Central European tree species (including the Carpathians) which we treat in detail with reference to an extensive literature survey on population genetic studies assembled from the whole of Europe. We further provide an overview of the population biology of associated understorey species. We conclude with recommended steps to be taken for the evaluation of potential perils of habitat fragmentation or population thinning for the genetics of tree populations. The complexity of effects exerted by life history traits and extrinsic characteristics of populations suggest population genetic development is strongly situation dependent. Therefore, we recommend following a case-by-case approach ideally supported by computer simulations to predict future population genetic development of both trees and associated understorey species. Full article
(This article belongs to the Special Issue Characterization and Preservation of Plant Genetic Diversity)
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Open AccessReview Known Predators of Crown-of-Thorns Starfish (Acanthaster spp.) and Their Role in Mitigating, If Not Preventing, Population Outbreaks
Diversity 2017, 9(1), 7; doi:10.3390/d9010007
Received: 20 November 2016 / Revised: 3 January 2017 / Accepted: 17 January 2017 / Published: 22 January 2017
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Abstract
Predatory release has long been considered a potential contributor to population outbreaks of crown-of-thorns starfish (CoTS; Acanthaster spp.). This has initiated extensive searches for potentially important predators that can consume large numbers of CoTS at high rates, which are also vulnerable to over-fishing
[...] Read more.
Predatory release has long been considered a potential contributor to population outbreaks of crown-of-thorns starfish (CoTS; Acanthaster spp.). This has initiated extensive searches for potentially important predators that can consume large numbers of CoTS at high rates, which are also vulnerable to over-fishing or reef degradation. Herein, we review reported predators of CoTS and assess the potential for these organisms to exert significant mortality, and thereby prevent and/or moderate CoTS outbreaks. In all, 80 species of coral reef organisms (including fishes, and motile and sessile invertebrates) are reported to predate on CoTS gametes (three species), larvae (17 species), juveniles (15 species), adults (18 species) and/or opportunistically feed on injured (10 species) or moribund (42 species) individuals within reef habitats. It is clear however, that predation on early life-history stages has been understudied, and there are likely to be many more species of reef fishes and/or sessile invertebrates that readily consume CoTS gametes and/or larvae. Given the number and diversity of coral reef species that consume Acanthaster spp., most of which (e.g., Arothron pufferfishes) are not explicitly targeted by reef-based fisheries, links between overfishing and CoTS outbreaks remain equivocal. There is also no single species that appears to have a disproportionate role in regulating CoTS populations. Rather, the collective consumption of CoTS by multiple different species and at different life-history stages is likely to suppress the local abundance of CoTS, and thereby mediate the severity of outbreaks. It is possible therefore, that general degradation of reef ecosystems and corresponding declines in biodiversity and productivity, may contribute to increasing incidence or severity of outbreaks of Acanthaster spp. However, it seems unlikely that predatory release in and of itself could account for initial onset of CoTS outbreaks. In conclusion, reducing anthropogenic stressors that reduce the abundance and/or diversity of potential predatory species represents a “no regrets” management strategy, but will need to be used in conjunction with other management strategies to prevent, or reduce the occurrence, of CoTS outbreaks. Full article
(This article belongs to the Special Issue Biology, Ecology and Management of Crown-of-Thorns Starfish)
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Open AccessReview Diversity of the Mountain Flora of Central Asia with Emphasis on Alkaloid-Producing Plants
Diversity 2017, 9(1), 11; doi:10.3390/d9010011
Received: 22 November 2016 / Revised: 11 February 2017 / Accepted: 13 February 2017 / Published: 17 February 2017
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Abstract
The mountains of Central Asia with 70 large and small mountain ranges represent species-rich plant biodiversity hotspots. Major mountains include Saur, Tarbagatai, Dzungarian Alatau, Tien Shan, Pamir-Alai and Kopet Dag. Because a range of altitudinal belts exists, the region is characterized by high
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The mountains of Central Asia with 70 large and small mountain ranges represent species-rich plant biodiversity hotspots. Major mountains include Saur, Tarbagatai, Dzungarian Alatau, Tien Shan, Pamir-Alai and Kopet Dag. Because a range of altitudinal belts exists, the region is characterized by high biological diversity at ecosystem, species and population levels. In addition, the contact between Asian and Mediterranean flora in Central Asia has created unique plant communities. More than 8100 plant species have been recorded for the territory of Central Asia; about 5000–6000 of them grow in the mountains. The aim of this review is to summarize all the available data from 1930 to date on alkaloid-containing plants of the Central Asian mountains. In Saur 301 of a total of 661 species, in Tarbagatai 487 out of 1195, in Dzungarian Alatau 699 out of 1080, in Tien Shan 1177 out of 3251, in Pamir-Alai 1165 out of 3422 and in Kopet Dag 438 out of 1942 species produce alkaloids. The review also tabulates the individual alkaloids which were detected in the plants from the Central Asian mountains. Quite a large number of the mountain plants produce neurotoxic and cytotoxic alkaloids, indicating that a strong chemical defense is needed under the adverse environmental conditions of these mountains with presumably high pressure from herbivores. Full article
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Open AccessReview Potential Enhanced Survivorship of Crown of Thorns Starfish Larvae due to Near-Annual Nutrient Enrichment during Secondary Outbreaks on the Central Mid-Shelf of the Great Barrier Reef, Australia
Diversity 2017, 9(1), 17; doi:10.3390/d9010017
Received: 7 December 2016 / Revised: 6 March 2017 / Accepted: 7 March 2017 / Published: 12 March 2017
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Abstract
The Great Barrier Reef (GBR) is currently experiencing widespread crown of thorns starfish (CoTS) outbreaks, as part of the fourth wave of outbreaks since 1962. It is believed that these outbreaks have become more frequent on the GBR and elsewhere in the Indo-Pacific
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The Great Barrier Reef (GBR) is currently experiencing widespread crown of thorns starfish (CoTS) outbreaks, as part of the fourth wave of outbreaks since 1962. It is believed that these outbreaks have become more frequent on the GBR and elsewhere in the Indo-Pacific and are associated with anthropogenic causes. The two widely accepted potential causes are (1) anthropogenic nutrient enrichment leading to the increased biomass of phytoplankton, the food of the planktonic stage of larval CoTS; and (2) the overfishing of predators in the juvenile to adult stages of CoTS, for example, commercially fished species such as coral trout. In this study, we show that the evidence for the nutrient enrichment causation hypothesis is strongly based on a large number of recent studies in the GBR. We also hypothesise that secondary outbreaks in the region between Cairns and Townsville can also be enhanced by nutrient enriched conditions associated with the annual nutrient discharge from Wet Tropics rivers. Full article
(This article belongs to the Special Issue Biology, Ecology and Management of Crown-of-Thorns Starfish)
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