Moussab/ORKG-training-evaluation-set huggingface dataset:
Research field: Ecology and Evolutionary Biology
Title: Reproductive potential and seedling establishment of the invasive alien tree Schinus molle (Anacardiaceae) in South Africa
Abstract: Schinus molle (Peruvian pepper tree) was introduced to South Africa more than 150 years ago and was widely planted, mainly along roads. Only in the last two decades has the species become naturalized and invasive in some parts of its new range, notably in semi-arid savannas. Research is being undertaken to predict its potential for further invasion in South Africa. We studied production, dispersal and predation of seeds, seed banks, and seedling establishment in relation to land uses at three sites, namely ungrazed savanna once used as a military training ground; a savanna grazed by native game; and an ungrazed mine dump. We found that seed production and seed rain density of S. molle varied greatly between study sites, but was high at all sites (384 864–1 233 690 seeds per tree per year; 3877–9477 seeds per square metre per year). We found seeds dispersed to distances of up to 320 m from female trees, and most seeds were deposited within 50 m of putative source trees. Annual seed rain density below canopies of Acacia tortillis, the dominant native tree at all sites, was significantly lower in grazed savanna. The quality of seed rain was much reduced by endophagous predators. Seed survival in the soil was low, with no survival recorded beyond 1 year. Propagule pressure to drive the rate of recruitment: densities of seedlings and sapling densities were higher in ungrazed savanna and the ungrazed mine dump than in grazed savanna, as reflected by large numbers of young individuals, but adult : seedling ratios did not differ between savanna sites. Frequent and abundant seed production, together with effective dispersal of viable S. molle seed by birds to suitable establishment sites below trees of other species to overcome predation effects, facilitates invasion. Disturbance enhances invasion, probably by reducing competition from native plants.
Extracted statement — Continent: Africa
Research field: Ecology and Evolutionary Biology
Title: Inferring Process from Pattern in Plant Invasions: A Semimechanistic Model Incorporating Propagule Pressure and Environmental Factors
Abstract: Propagule pressure is intuitively a key factor in biological invasions: increased availability of propagules increases the chances of establishment, persistence, naturalization, and invasion. The role of propagule pressure relative to disturbance and various environmental factors is, however, difficult to quantify. We explored the relative importance of factors driving invasions using detailed data on the distribution and percentage cover of alien tree species on South Africa’s Agulhas Plain (2,160 km2). Classification trees based on geology, climate, land use, and topography adequately explained distribution but not abundance (canopy cover) of three widespread invasive species (Acacia cyclops, Acacia saligna, and Pinus pinaster). A semimechanistic model was then developed to quantify the roles of propagule pressure and environmental heterogeneity in structuring invasion patterns. The intensity of propagule pressure (approximated by the distance from putative invasion foci) was a much better predictor of canopy cover than any environmental factor that was considered. The influence of environmental factors was then assessed on the residuals of the first model to determine how propagule pressure interacts with environmental factors. The mediating effect of environmental factors was species specific. Models combining propagule pressure and environmental factors successfully predicted more than 70% of the variation in canopy cover for each species.
Extracted statement — Continent: Africa
Research field: Ecology and Evolutionary Biology
Title: Invasive alien plants infiltrate bird-mediated shrub nucleation processes in arid savanna
Abstract: 1 The cultivation and dissemination of alien ornamental plants increases their potential to invade. More specifically, species with bird‐dispersed seeds can potentially infiltrate natural nucleation processes in savannas. 2 To test (i) whether invasion depends on facilitation by host trees, (ii) whether propagule pressure determines invasion probability, and (iii) whether alien host plants are better facilitators of alien fleshy‐fruited species than indigenous species, we mapped the distribution of alien fleshy‐fruited species planted inside a military base, and compared this with the distribution of alien and native fleshy‐fruited species established in the surrounding natural vegetation. 3 Abundance and diversity of fleshy‐fruited plant species was much greater beneath tree canopies than in open grassland and, although some native fleshy‐fruited plants were found both beneath host trees and in the open, alien fleshy‐fruited plants were found only beneath trees. 4 Abundance of fleshy‐fruited alien species in the natural savanna was positively correlated with the number of individuals of those species planted in the grounds of the military base, while the species richness of alien fleshy‐fruited taxa decreased with distance from the military base, supporting the notion that propagule pressure is a fundamental driver of invasions. 5 There were more fleshy‐fruited species beneath native Acacia tortilis than beneath alien Prosopis sp. trees of the equivalent size. Although there were significant differences in native plant assemblages beneath these hosts, the proportion of alien to native fleshy‐fruited species did not differ with host. 6 Synthesis. Birds facilitate invasion of a semi‐arid African savanna by alien fleshy‐fruited plants, and this process does not require disturbance. Instead, propagule pressure and a few simple biological observations define the probability that a plant will invade, with alien species planted in gardens being a major source of propagules. Some invading species have the potential to transform this savanna by overtopping native trees, leading to ecosystem‐level impacts. Likewise, the invasion of the open savanna by alien host trees (such as Prosopis sp.) may change the diversity, abundance and species composition of the fleshy‐fruited understorey. These results illustrate the complex interplay between propagule pressure, facilitation, and a range of other factors in biological invasions.
Extracted statement — Continent: Africa
Research field: Ecology and Evolutionary Biology
Title: Propagule pressure drives establishment of introduced freshwater fish: quantitative evidence from an irrigation network
Abstract: Propagule pressure is recognized as a fundamental driver of freshwater fish invasions, though few studies have quantified its role. Natural experiments can be used to quantify the role of this factor relative to others in driving establishment success. An irrigation network in South Africa takes water from an inter-basin water transfer (IBWT) scheme to supply multiple small irrigation ponds. We compared fish community composition upstream, within, and downstream of the irrigation network, to show that this system is a unidirectional dispersal network with a single immigration source. We then assessed the effect of propagule pressure and biological adaptation on the colonization success of nine fish species across 30 recipient ponds of varying age. Establishing species received significantly more propagules at the source than did incidental species, while rates of establishment across the ponds displayed a saturation response to propagule pressure. This shows that propagule pressure is a significant driver of establishment overall. Those species that did not establish were either extremely rare at the immigration source or lacked the reproductive adaptations to breed in the ponds. The ability of all nine species to arrive at some of the ponds illustrates how long-term continuous propagule pressure from IBWT infrastructure enables range expansion of fishes. The quantitative link between propagule pressure and success and rate of population establishment confirms the driving role of this factor in fish invasion ecology.
Extracted statement — Continent: Africa
Research field: Ecology and Evolutionary Biology
Title: Comparisons of isotopic niche widths of some invasive and indigenous fauna in a South African river
Abstract: Summary Biological invasions threaten ecosystem integrity and biodiversity, with numerous adverse implications for native flora and fauna. Established populations of two notorious freshwater invaders, the snail Tarebia granifera and the fish Pterygoplichthys disjunctivus, have been reported on three continents and are frequently predicted to be in direct competition with native species for dietary resources. Using comparisons of species' isotopic niche widths and stable isotope community metrics, we investigated whether the diets of the invasive T. granifera and P. disjunctivus overlapped with those of native species in a highly invaded river. We also attempted to resolve diet composition for both species, providing some insight into the original pathway of invasion in the Nseleni River, South Africa. Stable isotope metrics of the invasive species were similar to or consistently mid-range in comparison with their native counterparts, with the exception of markedly more uneven spread in isotopic space relative to indigenous species. Dietary overlap between the invasive P. disjunctivus and native fish was low, with the majority of shared food resources having overlaps of <0.26. The invasive T. granifera showed effectively no overlap with the native planorbid snail. However, there was a high degree of overlap between the two invasive species (˜0.86). Bayesian mixing models indicated that detrital mangrove Barringtonia racemosa leaves contributed the largest proportion to P. disjunctivus diet (0.12–0.58), while the diet of T. granifera was more variable with high proportions of detrital Eichhornia crassipes (0.24–0.60) and Azolla filiculoides (0.09–0.33) as well as detrital Barringtonia racemosa leaves (0.00–0.30). Overall, although the invasive T. granifera and P. disjunctivus were not in direct competition for dietary resources with native species in the Nseleni River system, their spread in isotopic space suggests they are likely to restrict energy available to higher consumers in the food web. Establishment of these invasive populations in the Nseleni River is thus probably driven by access to resources unexploited or unavailable to native residents.
Extracted statement — Continent: Africa
Research field: Ecology and Evolutionary Biology
Title: Predicting the landscape-scale distribution of alien plants and their threat to plant diversity
Abstract: Abstract: Invasive alien organisms pose a major threat to global biodiversity. The Cape Peninsula, South Africa, provides a case study of the threat of alien plants to native plant diversity. We sought to identify where alien plants would invade the landscape and what their threat to plant diversity could be. This information is needed to develop a strategy for managing these invasions at the landscape scale. We used logistic regression models to predict the potential distribution of six important invasive alien plants in relation to several environmental variables. The logistic regression models showed that alien plants could cover over 89% of the Cape Peninsula. Acacia cyclops and Pinus pinaster were predicted to cover the greatest area. These predictions were overlaid on the current distribution of native plant diversity for the Cape Peninsula in order to quantify the threat of alien plants to native plant diversity. We defined the threat to native plant diversity as the number of native plant species (divided into all species, rare and threatened species, and endemic species) whose entire range is covered by the predicted distribution of alien plant species. We used a null model, which assumed a random distribution of invaded sites, to assess whether area invaded is confounded with threat to native plant diversity. The null model showed that most alien species threaten more plant species than might be suggested by the area they are predicted to invade. For instance, the logistic regression model predicted that P. pinaster threatens 350 more native species, 29 more rare and threatened species, and 21 more endemic species than the null model would predict. Comparisons between the null and logistic regression models suggest that species richness and invasibility are positively correlated and that species richness is a poor indicator of invasive resistance in the study site. Our results emphasize the importance of adopting a spatially explicit approach to quantifying threats to biodiversity, and they provide the information needed to prioritize threats from alien species and the sites that need urgent management intervention.
Extracted statement — Continent: Africa
Research field: Ecology and Evolutionary Biology
Title: Herbivores, but not other insects, are scarce on alien plants
Abstract: Abstract Understanding how the landscape-scale replacement of indigenous plants with alien plants influences ecosystem structure and functioning is critical in a world characterized by increasing biotic homogenization. An important step in this process is to assess the impact on invertebrate communities. Here we analyse insect species richness and abundance in sweep collections from indigenous and alien (Australasian) woody plant species in South Africa's Western Cape. We use phylogenetically relevant comparisons and compare one indigenous with three Australasian alien trees within each of Fabaceae: Mimosoideae, Myrtaceae, and Proteaceae: Grevilleoideae. Although some of the alien species analysed had remarkably high abundances of herbivores, even when intentionally introduced biological control agents are discounted, overall, herbivorous insect assemblages from alien plants were slightly less abundant and less diverse compared with those from indigenous plants – in accordance with predictions from the enemy release hypothesis. However, there were no clear differences in other insect feeding guilds. We conclude that insect assemblages from alien plants are generally quite diverse, and significant differences between these and assemblages from indigenous plants are only evident for herbivorous insects.
Extracted statement — Continent: Africa
Research field: Ecology and Evolutionary Biology
Title: Plant invasions in Taiwan: Insights from the flora of casual and naturalized alien species
Abstract: Data on floristic status, biological attributes, chronology and distribution of naturalized species have been shown to be a very powerful tool for discerning the patterns of plant invasions and species invasiveness. We analysed the newly compiled list of casual and naturalized plant species in Taiwan (probably the only complete data set of this kind in East Asia) and found that Taiwan is relatively lightly invaded with only 8% of the flora being casual or naturalized. Moreover, the index of casual and naturalized species per log area is also moderate, in striking contrast with many other island floras where contributions of naturalized species are much higher. Casual and naturalized species have accumulated steadily and almost linearly over the past decades. Fabaceae, Asteraceae, and Poaceae are the families with the most species. However, Amaranthaceae, Convolvulaceae, and Onagraceae have the largest ratios of casual and naturalized species to their global numbers. Ipomoea, Solanum and Crotalaria have the highest numbers of casual and naturalized species. About 60% of all genera with exotic species are new to Taiwan. Perennial herbs represent one third of the casual and naturalized flora, followed by annual herbs. About 60% of exotic species were probably introduced unintentionally onto the island; many species imported intentionally have ornamental, medicinal, or forage values. The field status of 50% of these species is unknown, but ornamentals represent noticeable proportions of naturalized species, while forage species represent a relatively larger proportion of casual species. Species introduced for medicinal purposes seem to be less invasive. Most of the casual and naturalized species of Taiwan originated from the Tropical Americas, followed by Asia and Europe.
Extracted statement — Continent: Asia
Research field: Ecology and Evolutionary Biology
Title: Distributions of exotic plants in eastern Asia and North America
Abstract: Although some plant traits have been linked to invasion success, the possible effects of regional factors, such as diversity, habitat suitability, and human activity are not well understood. Each of these mechanisms predicts a different pattern of distribution at the regional scale. Thus, where climate and soils are similar, predictions based on regional hypotheses for invasion success can be tested by comparisons of distributions in the source and receiving regions. Here, we analyse the native and alien geographic ranges of all 1567 plant species that have been introduced between eastern Asia and North America or have been introduced to both regions from elsewhere. The results reveal correlations between the spread of exotics and both the native species richness and transportation networks of recipient regions. This suggests that both species interactions and human-aided dispersal influence exotic distributions, although further work on the relative importance of these processes is needed.
Extracted statement — Continent: Asia
Research field: Ecology and Evolutionary Biology
Title: Metazoan parasites of introduced round and tubenose gobies in the Great Lakes: Support for the "Enemy Release Hypothesis"
Abstract: ABSTRACT Recent invasion theory has hypothesized that newly established exotic species may initially be free of their native parasites, augmenting their population success. Others have hypothesized that invaders may introduce exotic parasites to native species and/or may become hosts to native parasites in their new habitats. Our study analyzed the parasites of two exotic Eurasian gobies that were detected in the Great Lakes in 1990: the round goby Apollonia melanostoma and the tubenose goby Proterorhinus semilunaris. We compared our results from the central region of their introduced ranges in Lakes Huron, St. Clair, and Erie with other studies in the Great Lakes over the past decade, as well as Eurasian native and nonindigenous habitats. Results showed that goby-specific metazoan parasites were absent in the Great Lakes, and all but one species were represented only as larvae, suggesting that adult parasites presently are poorly-adapted to the new gobies as hosts. Seven parasitic species are known to infest the tubenose goby in the Great Lakes, including our new finding of the acanthocephalan Southwellina hispida, and all are rare. We provide the first findings of four parasite species in the round goby and clarified two others, totaling 22 in the Great Lakes—with most being rare. In contrast, 72 round goby parasites occur in the Black Sea region. Trematodes are the most common parasitic group of the round goby in the Great Lakes, as in their native Black Sea range and Baltic Sea introduction. Holarctic trematode Diplostomum spathaceum larvae, which are one of two widely distributed species shared with Eurasia, were found in round goby eyes from all Great Lakes localities except Lake Huron proper. Our study and others reveal no overall increases in parasitism of the invasive gobies over the past decade after their establishment in the Great Lakes. In conclusion, the parasite “load” on the invasive gobies appears relatively low in comparison with their native habitats, lending support to the “enemy release hypothesis.”
Extracted statement — Continent: Asia
Research field: Economics
Title: Regional Competitiveness as an Aspect Promoting Sustainability of Latvia
Abstract: Providing of sustainability is one of the main priorities in normative documents in various countries. Factors affecting regional competitiveness is seen as close to them determining sustainability in many researches. The aim of this research was to identify and evaluate main factors of competitiveness for statistical regions of Latvia to promote sustainable development of the country, applying the complex regional competitiveness assessment system developed by the author. The analysis of the Regional Competitiveness Index (RCI) and its sub-indexes showed that each statistical region has both: factors promoting and hindering competitiveness. Overall the most competitive is Riga statistical region, but the last place takes Latgale statistical region. It is possible to promote equal regional development and sustainability of Latvia by implementing well-developed regional development strategy and National Action Plan. To develop such strategies, it is necessary to understand the concept of sustainable competitiveness. To evaluate sustainable competitiveness of Latvia and its regions it is necessary to develop further the methodology of regional competitiveness evaluation.
Extracted statement — State: Latvia
Research field: Energy Systems
Title: Optimal Sizing and Scheduling of Hybrid Energy Systems: The Cases of Morona Santiago and the Galapagos Islands
Abstract: Hybrid energy systems (HESs) generate electricity from multiple energy sources that complement each other. Recently, due to the reduction in costs of photovoltaic (PV) modules and wind turbines, these types of systems have become economically competitive. In this study, a mathematical programming model is applied to evaluate the techno-economic feasibility of autonomous units located in two isolated areas of Ecuador: first, the province of Galapagos (subtropical island) and second, the province of Morona Santiago (Amazonian tropical forest). The two case studies suggest that HESs are potential solutions to reduce the dependence of rural villages on fossil fuels and viable mechanisms to bring electrical power to isolated communities in Ecuador. Our results reveal that not only from the economic but also from the environmental point of view, for the case of the Galapagos province, a hybrid energy system with a PV–wind–battery configuration and a levelized cost of energy (LCOE) equal to 0.36 $/kWh is the optimal energy supply system. For the case of Morona Santiago, a hybrid energy system with a PV–diesel–battery configuration and an LCOE equal to 0.37 $/kWh is the most suitable configuration to meet the load of a typical isolated community in Ecuador. The proposed optimization model can be used as a decision-support tool for evaluating the viability of autonomous HES projects at any other location.
Extracted statement — Country of study: Ecuador