scholarly journals Asexual Regeneration Response of Ilex canariensis Poir. to Management of the Canopy of Pinus radiata D.Don

Ecologies ◽  
2020 ◽  
Vol 1 (1) ◽  
pp. 14-21
Author(s):  
José Ramón Arévalo

Exotic afforestation can provide suitable conditions for native shade-tolerant species restoration without threatening native forests. This study analyzes the impact of different thinning intensities of the canopy of an exotic Pinus radiata stand on the asexual regeneration response of Ilex canariensis, a native laurel forest species in the Canary Islands, Spain. The results provide useful indications for how to manage P. radiata stands to promote recovery of native plant communities. For different stand treatments were selected: stand clear cut, low intensity thinning (10–15%), high intensity thinning (25%), and a control. The stand clear cut management revealed Ilex canariensis individuals with a higher number of sprouts and more leaf cover; however, the height of these sprouts two years after the cut did not reach the values of individuals prior to this management. Consequently, the vitality index following clear cut management is significantly lower with respect to the other treatments. Thinning management is shown not to be so useful to promote the growth and vitality of Ilex canariensis individuals. The results suggest that thinning over 50% could be more appropriate in the case of Pinus radiata, allowing resprouting of Ilex canariensis in the understory and improvement in the vitality index.

Land ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 455
Author(s):  
Rebecca M. Swab ◽  
Nicola Lorenz ◽  
Nathan R. Lee ◽  
Steven W. Culman ◽  
Richard P. Dick

After strip mining, soils typically suffer from compaction, low nutrient availability, loss of soil organic carbon, and a compromised soil microbial community. Prairie restorations can improve ecosystem services on former agricultural lands, but prairie restorations on mine lands are relatively under-studied. This study investigated the impact of prairie restoration on mine lands, focusing on the plant community and soil properties. In southeast Ohio, 305 ha within a ~2000 ha area of former mine land was converted to native prairie through herbicide and planting between 1999–2016. Soil and vegetation sampling occurred from 2016–2018. Plant community composition shifted with prairie age, with highest native cover in the oldest prairie areas. Prairie plants were more abundant in older prairies. The oldest prairies had significantly more soil fungal biomass and higher soil microbial biomass. However, many soil properties (e.g., soil nutrients, β-glucosoidase activity, and soil organic carbon), as well as plant species diversity and richness trended higher in prairies, but were not significantly different from baseline cool-season grasslands. Overall, restoration with prairie plant communities slowly shifted soil properties, but mining disturbance was still the most significant driver in controlling soil properties. Prairie restoration on reclaimed mine land was effective in establishing a native plant community, with the associated ecosystem benefits.


2021 ◽  
pp. 1-21
Author(s):  
Davide Vittori

Abstract Scholars have long debated whether populism harms or improves the quality of democracy. This article contributes to this debate by focusing on the impact of populist parties in government. In particular, it inquires: (1) whether populists in government are more likely than non-populists to negatively affect the quality of democracies; (2) whether the role of populists in government matters; and (3) which type of populism is expected to negatively affect the quality of liberal-democratic regimes. The results find strong evidence that the role of populists in government affects several qualities of democracy. While robust, the findings related to (2) are less clear-cut than those pertaining to (1). Finally, regardless of their role in government, different types of populism have different impacts on the qualities of democracy. The results show that exclusionary populist parties in government tend to have more of a negative impact than other forms of populism.


Economies ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 76
Author(s):  
Giedrė Dzemydaitė

The smart specialization concept was implemented in the EU in 2014, stating that regions have to specify specialization areas for development of innovations. Economic specialization reveals a comparative advantage in that field. However, there are different arguments linking specialization to economic development. This study analyzes these arguments and aims to investigate the impact of economic specialization on regional economic development and to give insights into identifying prospective areas in regional economies. A panel fixed effect estimation of industry-level regional data suggests that economic specialization in broader regional employment, called relative specialization, is ambiguously associated with economic development. Our findings suggest that neither economic specialization nor economic diversity are a clear-cut solution for ensuring economic growth. Economic structure in EU regions differs, and there is no one answer for which approach is better for economic development. Specialization measures, particularly the location quotient, cannot fully capture the dynamics in the industry structure that could be essential for formation of regional development strategy.


2021 ◽  
Author(s):  
Jian Li ◽  
Zhanrui Leng ◽  
Yueming Wu ◽  
Yizhou Du ◽  
Zhicong Dai ◽  
...  

Abstract Global changes have altered the distribution pattern of the plant communities, including invasive species. Anthropogenic contamination may reduce native plant resistance to the invasive species. Thus, the focus of the current review is on the contaminant biogeochemical behavior among native plants, invasive species and the soil within the plant-soil ecosystem to improve our understanding of the interactions between invasive plants and environmental stressors. Our studies together with synthesis of the literature showed that a) the impacts of invasive species on environmental stress were heterogeneous, b) the size of the impact was variable, and c) the influence types were multidirectional even within the same impact type. However, invasive plants showed self-protective mechanisms when exposed to heavy metals (HMs) and provided either positive or negative influence on the bioavailability and toxicity of HMs. On the other hand, HMs may favor plant invasion due to the widespread higher tolerance of invasive plants to HMS together with the “escape behavior” of native plants when exposed to toxic HM pollution. However, there has been no consensus on whether elemental compositions of invasive plants are different from the natives in the polluted regions. A quantitative research comparing plant, litter and soil contaminant contents between native plants and the invaders in a global context is an indispensable research focus in the future.


2019 ◽  
pp. 107-120
Author(s):  
Robert Chazan

Beginning in the twelfth century, edicts of expulsion set in motion for the first time since early antiquity forced Jewish population movement. There have arguably been two further sources of pre-modern involuntary Jewish migration—repressive governmental edicts that made Jewish life spiritually or materially impossible and popular violence so threatening as to necessitate flight. Neither of these pressures is clear-cut in its impact, as were the edicts of expulsion from European states. This chapter considers the impact of both these pressures on Jewish population movement. It describes instances of abrogation of basic Jewish religious rights, expressed as governmental demands that Jews convert to the ruling faith.


Biologia ◽  
2017 ◽  
Vol 72 (7) ◽  
Author(s):  
Mária Petrášová-Šibíková ◽  
Igor Matečný ◽  
Eva Uherčíková ◽  
Peter Pišút ◽  
Silvia Kubalová ◽  
...  

AbstractHuman alteration of watercourses is global phenomenon that has had significant impacts on local ecosystems and the services they provide. Monitoring of abiotic and biotic changes is essential to mitigating long-lasting effects, and the 23-year dataset from the Gabčíkovo Waterworks provided a rare opportunity to assess the impact of groundwater regimes on vegetation. The main aim of this study was to describe the effect of the Gabčíkovo Waterworks on vegetation structure and species composition of the adjacent riparian floodplain forests over the past 23 years. The results are based on studies of three permanent monitoring plots (PMPs) located in the Danube inland delta – two outside (PMP 1 and 3) and one (PMP 2) fully under the influence of the artificial supply system. Our results demonstrate that the Danube inland delta was negatively affected by the Gabčíkovo construction, particularly for sites outside of the artificial supply system. There was a significant decrease in soil moisture and increase in nitrogen at both external PMPs (1 and 3). Alter soil conditions were accompanied by negative changes in plant species composition demonstrated by decreases in the number of typical floodplain forest species that are characteristic for the alliance


1997 ◽  
Vol 45 (4) ◽  
pp. 439-450 ◽  
Author(s):  
R.G.A. Boot

Tropical rain forests are rich in plant and animal species. The sustainable extraction of non-timber forest products has been advocated as a strategy to best conserve this diversity. However, the development and implementation of such exploitation systems, which aim to reconcile conservation and economic development, are still hampered by the lack of information on the biological sustainability of these systems, the impact of these exploitation systems on the biological diversity and the insufficient knowledge of the role of forest products in the household economy of forest dependent people and hence their prospects for economic development. Whether the exploitation of non-timber forest products from tropical rain forests is sustainable or not is still open to question, but data presently available on the biological, social and economic aspects of these extraction systems point at an interesting question: does diversity come at a price? Namely, low density of conspecifics, and thus products, and hence low productivity for those involved in the collection of forest resources. The paper will further discuss whether domestication of forest species provides an alternative for some of these species. Species are part of a complex ecosystem and their functioning is partly depended on the presence of other species in the system. The attributes of the species which have to be taken into account in order to make domestication of forest species successful are considered. Finally, the paper returns to the question of how to reconcile conservation and use of tropical rain forests. It will present a case for domesticating the forest instead of the species or, in other words, changing the forest composition without changing its structure and functioning, and maintaining acceptable levels of biodiversity.


2020 ◽  
Vol 125 (6) ◽  
pp. 955-967 ◽  
Author(s):  
Mireia Gomez-Gallego ◽  
Nari Williams ◽  
Sebastian Leuzinger ◽  
Peter Matthew Scott ◽  
Martin Karl-Friedrich Bader

Abstract Background and Aims Biotic and abiotic stressors can cause different defoliation patterns within trees. Foliar pathogens of conifers commonly prefer older needles and infection with defoliation that progresses from the bottom crown to the top. The functional role of the lower crown of trees is a key question to address the impact of defoliation caused by foliar pathogens. Methods A 2 year artificial defoliation experiment was performed using two genotypes of grafted Pinus radiata to investigate the effects of lower-crown defoliation on carbon (C) assimilation and allocation. Grafts received one of the following treatments in consecutive years: control–control, control–defoliated, defoliated–control and defoliated–defoliated. Results No upregulation of photosynthesis either biochemically or through stomatal control was observed in response to defoliation. The root:shoot ratio and leaf mass were not affected by any treatment, suggesting prioritization of crown regrowth following defoliation. In genotype B, defoliation appeared to impose C shortage and caused reduced above-ground growth and sugar storage in roots, while in genotype A, neither growth nor storage was altered. Root C storage in genotype B decreased only transiently and recovered over the second growing season. Conclusions In genotype A, the contribution of the lower crown to the whole-tree C uptake appears to be negligible, presumably conferring resilience to foliar pathogens affecting the lower crown. Our results suggest that there is no C limitation after lower-crown defoliation in P. radiata grafts. Further, our findings imply genotype-specific defoliation tolerance in P. radiata.


Agronomy ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 300 ◽  
Author(s):  
Pradeep Wagle ◽  
Prasanna Gowda

Adoption of better management practices is crucial to lessen the impact of anthropogenic disturbances on tallgrass prairie systems that contribute heavily for livestock production in several states of the United States. This article reviews the impacts of different common management practices and disturbances (e.g., fertilization, grazing, burning) and tallgrass prairie restoration on plant growth and development, plant species composition, water and nutrient cycles, and microbial activities in tallgrass prairie. Although nitrogen (N) fertilization increases aboveground productivity of prairie systems, several factors greatly influence the range of stimulation across sites. For example, response to N fertilization was more evident on frequently or annually burnt sites (N limiting) than infrequently burnt and unburnt sites (light limiting). Frequent burning increased density of C4 grasses and decreased plant species richness and diversity, while plant diversity was maximized under infrequent burning and grazing. Grazing increased diversity and richness of native plant species by reducing aboveground biomass of dominant grasses and increasing light availability for other species. Restored prairies showed lower levels of species richness and soil quality compared to native remnants. Infrequent burning, regular grazing, and additional inputs can promote species richness and soil quality in restored prairies. However, this literature review indicated that all prairie systems might not show similar responses to treatments as the response might be influenced by another treatment, timing of treatments, and duration of treatments (i.e., short-term vs. long-term). Thus, it is necessary to examine the long-term responses of tallgrass prairie systems to main and interacting effects of combination of management practices under diverse plant community and climatic conditions for a holistic assessment.


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