scholarly journals Macrothelypteris torresiana (swordfern).

Author(s):  
Julissa Rojas-Sandoval

Abstract Macrothelypteris torresiana is a perennial fern native to Asia, Madagascar, the Mascarene Islands and Oceania. It has been widely introduced across the Americas as an ornamental plant. It grows in disturbed areas including roadsides and forest edges and behaves as a weed. It spreads via spores in wind and water but can also spread via stolons and rhizomes in garden waste. Currently, M. torresiana is listed as invasive in Cuba and Brazil and may also be invasive in Hawaii where it is spreading. The impact of this species where it is invasive is largely unknown, but it is possible that its weedy and opportunistic nature results in competition with native species and alteration of successional patterns.

2016 ◽  
Vol 4 ◽  
pp. 257-261
Author(s):  
Barbora Holienková ◽  
Zuzana Krumpálová

Recently, the number of alien landscape species has dramatically increased, and this could be a serious threat, not only for native species but also in cases of outbreaks for farmers. Our objective was to examine the impact of the urban environment (positive or negative) on the diversity of native species; forecast biotic homogenization or diversification of urban fauna; and determine the extent to which each of the zones are affected by invasive species. To examine the effect of urbanization, we selected 16 areas (across three urban zones and one zone in the protected area for comparison) for this study in 2015 in Nitra. We found that snails in open locations had significantly greater species diversity and abundance of individuals than in closed locations. Slightly degraded areas had the most abundant snail species, but areas heavily disturbed had high species diversity and incidence of individuals. It appears that heavily disturbed areas are suitable as new types of refuge for snails, e.g., for Helix lucorum, which was recorded in Slovakia for the first time (numerically recorded at the railway station) in 2014.


2010 ◽  
Vol 26 (3) ◽  
pp. 347-350 ◽  
Author(s):  
Jannie Fries Linnebjerg ◽  
Dennis M. Hansen ◽  
Nancy Bunbury ◽  
Jens M. Olesen

Disruption of ecosystems is one of the biggest threats posed by invasive species (Mack et al. 2000). Thus, one of the most important challenges is to understand the impact of exotic species on native species and habitats (e.g. Jones 2008). The probability that entire ‘invasive communities’ will develop increases as more species establish in new areas (Bourgeois et al. 2005). For example, introduced species may act in concert, facilitating one another's invasion, and increasing the likelihood of successful establishment, spread and impact. Simberloff & Von Holle (1999) introduced the term ‘invasional meltdown’ for this process, which has received widespread attention since (e.g. O'Dowd 2003, Richardson et al. 2000, Simberloff 2006). Positive interactions among introduced species are relatively common, but few have been studied in detail (Traveset & Richardson 2006). Examples include introduced insects and birds that pollinate and disperse exotic plants, thereby facilitating the spread of these species into non-invaded habitats (Goulson 2003, Mandon-Dalger et al. 2004, Simberloff & Von Holle 1999). From a more general ecological perspective, the study of interactions involving introduced and invasive species can contribute to our knowledge of ecological processes – for example, community assembly and indirect interactions.


2021 ◽  
Vol 27 (2) ◽  
pp. 232-237
Author(s):  
Ni Made Armini Wiendi ◽  
Nessa Maulida ◽  
Krisantini Krisantini

Abstract Eleutherine bulbosa is a known ornamental plant of the Iris family, which originated from Central Borneo, Indonesia. The bulbs of E. bulbosa have long been used as a medicinal source by the local people of Borneo. Despite its known medicinal and other values, studies on the morphology and efficiency in bulb production of this species are limited. The aims of our study are to examine the vegetative and reproductive morphology of E. bulbosa, and to determine the effect of various dosages of NPK fertilizer on flowering and bulb production. The plants were grown in pots using potting mix consists of equal volume of burnt rice hulls, cocopeat, and organic manures (1:1:1). Our study showed that E. bulbosa has a cymose rhipidium inflorescence with 25-50 mm long peduncles, have 3-4 umbel on the secondary axis, each consists of 10-12 florets that opens in turn every day. Florets are 20-30 mm long, 20 mm in diameter, 10-15 mm pedicels, and short-lived. The perianth is white, about 25 mm wide with yellow anthers and stigma. Fruits were not formed during the duration of the study. NPK fertilizer application at the lowest dose of 1 g per pot had promoted earlier shoot emergence and vegetative growth, including plant height, leaf number, leaf size, number of tillers, and bulb production compared to control (no fertilizer). Application of fertilizer at 1 and 2 g per plant significantly promoted earlier flowering, whereas application at 3 g per plant delayed and reduced the proportion of flowering plants. The results of this study can aid in taxonomic identification and efficient cultivation of this plant for uses as potted flowering ornamentals or bulb production for different purposes. Higher cultivation and reduced wild harvesting can result in the conservation of this species.


Behaviour ◽  
2021 ◽  
pp. 1-21
Author(s):  
Pooja Panwar ◽  
Pilar Angélica Gómez-Ruiz ◽  
Matthew N. Zipple ◽  
Luis Sandoval

Abstract Studies on the impact of human activity on animal behaviour are critical for understanding the extent to which humans affect ecological dynamics. Previous studies have found that human presence alters antipredator behaviours, which can be measured by flight initiation distance (FID). We investigated escape behaviour of 96 black iguanas (Ctenosaura similis) across a gradient of human disturbance in six sites inside a protected area in Costa Rica. We used a field experiment to test for effect of human disturbance on FID. We found that individuals from higher disturbance sites had shorter FIDs, meaning that black iguanas from disturbed areas allow closer approaches. This finding is consistent with the prediction that some animals become more habituated to human presence as the degree of human disturbance increases. We propose that black iguanas’ ability to alter their behaviour in response to humans’ presence could make them especially adept at invading new environments.


2021 ◽  
Author(s):  
Julissa Rojas-Sandoval

Abstract Oldenlandia corymbosa is a widespread polymorphic weed with a pantropical distribution. It is fast-growing and can rapidly colonize disturbed areas, open sites, gardens, farmlands, forest edges, grasslands, roadsides and riverbanks. O. corymbosa also produces large volumes of tiny seeds that can be easily dispersed by water, animals and vehicles, or as a contaminant in soil and agricultural produce. Its weedy habit, preference for disturbed sites and tiny seeds all facilitate its spread and colonization of new habitats.


2021 ◽  
Vol 71 (2) ◽  
pp. 95-100
Author(s):  
G. B. Lindsey ◽  
T. L. Amburgey ◽  
H. M. Barnes

Abstract The objective of this study was to determine the impact on termite feeding of wood sample size and species and test photoperiod in standard tests. Native species (Reticulitermes flavipes) and introduced species (Coptotermes formosanus) were tested in an American Wood-Preservers' Association E1 standard laboratory test. For testing involving treated wood, southern yellow pine was determined to be preferable to spruce based on its treatability and availability. Test blocks of 25 by 25 by 6 mm were deemed adequate for testing, with large blocks presenting difficulty with retrieval of termites to determine mortality and smaller blocks being consumed too rapidly by the termites in the test. Photoperiod comparisons were not significantly different for R. flavipes; however, C. formosanus indicated a preference for 100 percent darkness. Therefore, the recommendation is to maintain tests using each species in a 100 percent dark environment.


2019 ◽  
Vol 12 (1) ◽  
pp. 204 ◽  
Author(s):  
Yang Cao ◽  
Yosihiro Natuhara

Riparian areas are local hot spots of biodiversity that are vulnerable and easily degraded. Comparing plant communities in habitats with different degrees of urbanization may provide valuable information for the management and restoration of these vulnerable habitats. In this study, we explored the impact of urbanization on vegetation communities between artificial and semi-natural habitats within two rivers with different levels of development. We compared species richness, types of vegetation, and composition patterns of the plants in our study. In artificial habitats, the sites with relatively high levels of urbanization had the highest species richness, while in semi-natural habitats, the highest species richness was recorded in the less urbanized sites. Furthermore, every component of urbanization that contributed to the variation of species richness was examined in the current study. In artificial habitats, the proportion of impervious surface was the strongest predictor of the variation in species richness and was associated with the richness of alien, native, and riparian species. In semi-natural habitats, most of the richness of alien and native species were associated with the distance to the city center, and the number of riparian and ruderal species was significantly related to the proportion of impervious surface. Moreover, we found that a high level of urbanization was always associated with a large abundance of alien and ruderal species in both artificial and in semi-natural habitats. We recommend the methods of pair comparison of multiple rivers to analyze the impact of urbanization on plant species in riparian areas and have suggested various management actions for maintaining biodiversity and sustainability in riparian ecosystems.


2003 ◽  
Vol 30 (6) ◽  
pp. 565 ◽  
Author(s):  
A. D. Arthur ◽  
R. P. Pech ◽  
A. Drew ◽  
E. Gifford ◽  
S. Henry ◽  
...  

We investigated experimentally the influence of habitat structure on the population dynamics of house mice. Three habitat types were used. In one, dense stands of regenerating cypress pine were felled and left in situ to cover at least 40% of experimental plots, providing high complexity at ground level; in another, dense stands of regenerating pine were left intact, providing low complexity at ground level; in the third, open grassland adjacent to dense stands of regenerating pine also provided low complexity at ground level. Mouse populations occurred at higher densities in felled pine plots compared with both the standing pine and grassland plots, consistent with the hypothesis that the presence of increased habitat complexity at ground level reduced the impact of predation. Even though populations responded to the felled pine, they dropped to very low densities over winter, suggesting that the habitat was still marginal for the persistence of mice, probably due to a lack of food. The results are discussed with reference to their implications for the influence that habitat structure may have on the impact of introduced predators on native species.


Proceedings ◽  
2019 ◽  
Vol 18 (1) ◽  
pp. 10 ◽  
Author(s):  
Federico Filipponi ◽  
Giacinto Manfron

Information related to the impact of wildfire disturbances on ecosystems is of paramount interest to account for environmental loss, to plan strategies for facilitating ecosystem restoration, and to monitor the dynamics of vegetation restoration. Phenological metrics can represent a good candidate to monitor and quantify vegetation recovery after natural hazards like wildfire disturbances. Satellite observations have been demonstrated to be a suitable tool for wildfire disturbed areas monitoring, allowing both the identification of burned areas and the monitoring of vegetation recovery. This research study aims to identify post-fire vegetation restoration dynamics for the area surrounding Naples (Italy), affected by severe wildfires events in 2017. Sentinel-2 satellite data were used to extract phenological metrics from the estimated Leaf Area Index (LAI) and to relate such metrics to environmental variables in order to evaluate the vegetation restoration and landslide susceptibility for different land use classes.


Parasitology ◽  
2020 ◽  
Vol 147 (6) ◽  
pp. 706-714 ◽  
Author(s):  
John Rhidian Thomas ◽  
Chloe V. Robinson ◽  
Agata Mrugała ◽  
Amy R. Ellison ◽  
Emily Matthews ◽  
...  

AbstractThe spread of invasive, non-native species is a key threat to biodiversity. Parasites can play a significant role by influencing their invasive host's survival or behaviour, which can subsequently alter invasion dynamics. The North American signal crayfish (Pacifastacus leniusculus) is a known carrier of Aphanomyces astaci, an oomycete pathogen that is the causative agent of crayfish plague and fatal to European crayfish species, whereas North American species are considered to be largely resistant. There is some evidence, however, that North American species, can also succumb to crayfish plague, though how A. astaci affects such ‘reservoir hosts’ is rarely considered. Here, we tested the impact of A. astaci infection on signal crayfish, by assessing juvenile survival and adult behaviour following exposure to A. astaci zoospores. Juvenile signal crayfish suffered high mortality 4-weeks post-hatching, but not as older juveniles. Furthermore, adult signal crayfish with high-infection levels displayed altered behaviours, being less likely to leave the water, explore terrestrial areas and exhibit escape responses. Overall, we reveal that A. astaci infection affects signal crayfish to a much greater extent than previously considered, which may not only have direct consequences for invasions, but could substantially affect commercially harvested signal crayfish stocks worldwide.


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