Forest canopy resists plant invasions: a case study of Chromolaena odorata in Sal (Shorea robusta) forests of Nepal

2022 ◽  
pp. 1-9
Author(s):  
L. N. Sharma ◽  
B. Adhikari ◽  
M. F. Watson ◽  
B. B. Shrestha ◽  
E. Paudel ◽  
...  
Keyword(s):  
Alien Species ◽  
Forest Canopy ◽  
Invasive Alien Species ◽  
Canopy Cover ◽  
Economic Damage ◽  
Shrub Cover ◽  
Chromolaena Odorata ◽  
Alien Plant ◽  
Community Forests ◽  
Shorea Robusta

Abstract Invasive alien species are a major threat to global biodiversity due to the tremendous ecological and economic damage they cause in forestry, agriculture, wetlands, and pastoral resources. Understanding the spatial pattern of invasive alien species and disentangling the biophysical drivers of invasion at the forest stand level is essential for managing forest ecosystems and the wider landscape. However, forest-level and species-specific information on Invasive Alien Plant Species (IAPS) abundance and their spatial extent are largely lacking. In this context, we analysed the cover of one of the world’s worst invasive plants, Chromolaena odorata, in Sal (Shorea robusta) forest in central Nepal. Vegetation was sampled in four community forests using 0.01 ha square quadrats, covering the forest edge to the interior. C. odorata cover, floral richness, tree density, forest canopy cover, shrub cover, tree basal area, and disturbances were measured in each plot. We also explored forest and IAPS management practices in community forests. C. odorata cover was negatively correlated with forest canopy cover, distance to the road, angle of slope, and shrub cover. Tree canopy cover had the largest effect on C. odorata cover. No pattern of C. odorata cover was seen along native species richness gradients. In conclusion, forest canopy cover is the overriding biotic covariate suppressing C. odorata cover in Sal forests.

scholarly journals Forest canopy resists plant invasions: a case study of Chromolaena odorata in sub-tropical Sal (Shorea robusta) forests of Nepal

2019 ◽  
Author(s):  
LN Sharma ◽  
B Adhikari ◽  
MF Watson ◽  
B Karna ◽  
E Paudel ◽  
...  
Keyword(s):  
Invasive Species ◽  
Forest Canopy ◽  
Management Practices ◽  
Forest Ecosystems ◽  
Canopy Cover ◽  
Economic Damage ◽  
Specific Information ◽  
Shrub Cover ◽  
Chromolaena Odorata ◽  
Shorea Robusta

AbstractInvasive Alien Species cause tremendous ecological and economic damage in agriculture, forestry, aquatic ecosystems, and pastoral resources. They are one of the major threats to biodiversity conservation. Understanding the spatial pattern of invasive species and disentangling the biophysical drivers of invasion at forest stand level is essential for managing invasive species in forest ecosystems and the wider landscape. However, forest-level and species-specific information on invasive species abundance and area of extent is largely lacking. In this context, we analysed the cover of one of the world’s worst invasive plant species Chromolaena odorata in Sal (Shorea robusta Gaertn.) forest in central Nepal. Vegetation was sampled in four community-managed forests using 0.01 ha square quadrats, covering forest edge to the interior. Chromolaena cover, floral richness, tree density, forest canopy cover, shrub cover, and tree basal area were measured in each plot. We also estimated the level of disturbance in plots, and calculated distance from the plot to the nearest road. We also explored forest and invasive species management practices in community forests.Chromolaena cover was found to be negatively correlated with forest canopy cover, distance to the nearest road, angle of slope and shrub cover. Canopy cover had the greatest effect on the Chromolaena cover. Chromolaena cover did not show any pattern along native species richness gradients. In conclusion, forest canopy cover is the overriding biotic covariate affecting Chromolaena cover in Sal forests. The practical application of our results in managing Chromolaena in forest ecosystems is discussed.

scholarly journals Introduction and Spread of the Invasive Alien Species Ageratina altissima in a Disturbed Forest Ecosystem

2021 ◽  
Vol 13 (11) ◽  
pp. 6152
Author(s):  
Eunyoung Kim ◽  
Jaeyong Choi ◽  
Wonkyong Song
Keyword(s):  
Land Use ◽  
South Korea ◽  
Alien Species ◽  
Invasive Alien Species ◽  
Management Policy ◽  
Economic Damage ◽  
Forest Edges ◽  
Forest Interior ◽  
Lower Elevation ◽  
Canopy Area

Invasive alien species (IAS) not only displace nearby indigenous plants and lead to habitat simplification but also cause severe economic damage by invading arable lands. IAS invasion processes involve external forces such as species characteristics, IAS assemblage traits, environmental conditions, and inter-species interactions. In this study, we analyzed the invasion processes associated with the introduction and spread of Ageratina altissima, a representative invasive plant species in South Korea. We investigated 197 vegetation quadrats (2 × 20 m) in regions bordering 47 forests in southern Seoul and Gyeonggi-do, South Korea. A total of 23 environmental variables were considered, which encompassed vegetation, topography, land use, and landscape ecology indices. The model was divided into an edge and an interior model and analyzed using logistic regression and a decision tree (DT) model. The occurrence of Ageratina altissima was confirmed in 61 sites out of a total of 197. According to our analysis, Ageratina altissima easily invaded forest edges with low density. The likelihood of its occurrence increased with lower elevation and gentler slope. In contrast, the spread of Ageratina altissima in the forest interior, especially based on seed spread and permeability, was favored by a lower elevation and gentler slopes. The analysis of Ageratina altissima settlement processes in forest edges coupled with the DT model demonstrated that land characteristics, such as the proximity to urbanized areas and the number of shrub and tree species, play a pivotal role in IAS settlement. In the forest interior, Ageratina altissima did not occur in 68 of the 71 sites where the soil drainage was under 2.5%, and it was confirmed that the tree canopy area had a significant impact on forest spread. Based on these results, it can be assumed that Ageratina altissima has spread in South Korean forests in much the same way as other naturalized species. Therefore, vegetation management strategies for naturalized species should be developed in parallel with land use management policy in regions surrounding forest edges to successfully manage and control Ageratina altissima invasion.

scholarly journals Status and impacts of invasive alien plant species in Parsa National Park, central Nepal

2020 ◽  
Vol 30 (1) ◽  
pp. 21-31 ◽  
Author(s):  
R. Chaudhary ◽  
B. B. Shrestha ◽  
H. Thapa ◽  
M. Siwakoti
Keyword(s):  
Alien Species ◽  
Plant Species ◽  
National Parks ◽  
National Park ◽  
Invasive Alien Species ◽  
Plant Invasions ◽  
Tree Regeneration ◽  
Alien Plant Species ◽  
Alien Plant ◽  
Invasive Alien Plant

Extent of plant invasions has been expected to be low in protected areas such as national parks due to low anthropogenic activities and high wilderness. However, recent researches across the world have revealed that plant invasions can be severe in the national parks with negative impacts on the protected species and ecosystems. Unfortunately, the status of plant invasions in the national parks of Nepal is mostly unknown. In this study, we sampled at seven locations inside the Parsa National Park (PNP) to document diversity and abundance of invasive alien plant species (IAPS) and their impacts on tree regeneration. Altogether, 130 quadrats of 10 m × 10 m were sampled. We recorded 14 IAPS in the PNP. Three of the IAPS (Chromolana odorata, Lantana camara and Mikania micrantha) were among the 100 of the world’s worst invasive alien species. C. odorata was found to be the most frequent IAPS with the highest cover. The frequency and cover of the IAPS were higher at the sites close to the settlements than at the sites away from the settlements. The species richness of the IAPS was also higher at the sites closer to the settlements than away. The sapling density of the tree species was found to have declined with the increasing cover of the IAPS suggesting that the IAPS had negatively affected tree regeneration. Our data revealed that the PNP has already witnessed massive plant invasions with widespread occurrence of three of the world’s worst invasive species. Therefore, it is high time to integrate management of invasive alien species in the management plan of the park.

scholarly journals Host plant preference of Metcalfa pruinosa (Say, 1830) (Hemiptera: Flatidae) in the north of Hungary

2015 ◽  
pp. 84-95
Author(s):  
András Bozsik
Keyword(s):  
Population Density ◽  
Alien Species ◽  
Invasive Alien Species ◽  
Ornamental Plants ◽  
Economic Damage ◽  
Fruit Crops ◽  
Railway Line ◽  
The North ◽  
Significant Damage ◽  
Long Time

Citrus flatid planthopper, a native insect to North America had for a long time a scarce economic importance there. However, being polyphagous made little damage on citrus trees and some ornamentals. In 1979 it was introduced to Italy where it established and spread quickly. It is now an invasive alien species continually spreading in South and Central Europe causing considerable damage in fruit crops and various ornamentals. Present study shows the results of a series of observations carried out from 2011 to 2015 at a number of habitats in north of Hungary. The pest could be found at each habitat but the hedge, the tree row, the gardens and the orchard/vineyard were the most infested. Frequency and population density of Metcalfa pruinosa were considerable on Asteraceae, Cannabaceae, Fabaceae, Juglandaceae, Lamiaceae, Rosaceae and Sapindaceae. Typical vegetation could be functionally classified as ornamental plants, trees/shrubs, fruit plants, weeds and feral plants. Feral plants – some of them also invasive alien species – were found at each habitat. Plant species native to America were among them the most populated. As the hedgerows were neglected, and most gardens, orchards and vineyards abandoned, these are excellent conditions for the quick and long-lasting establishment of the pest as well as they may be reservoirs to infest cultivated fruit crops and ornamentals. The hedgerow was situated along a railway line. The length of similar hedges can be merely in Pest county several hundred km, which means M. pruinosa has plenty of opportunity for spreading along the railway and infest agricultural and ornamental cultures. On the surveyed alfalfa and maize fields, accidentally very few nymphs and adults were observed. Although, the population density of M. pruinosa was considerable on many hostplants, economic damage or yield losses could not be detected. Economic or significant damage was observed only on roses, raspberries and stinging nettle. This later is cultivated in Germany and Finland. The applied horticultural oil was efficient.

scholarly journals Assessing the relative potential ecological impacts and invasion risks of emerging and future invasive alien species

NeoBiota ◽  
2018 ◽  
Vol 40 ◽  
pp. 1-24 ◽  
Author(s):  
James W.E. Dickey ◽  
Ross N. Cuthbert ◽  
Michael Rea ◽  
Ciaran Laverty ◽  
Kate Crane ◽  
...  
Keyword(s):  
Alien Species ◽  
Attack Rate ◽  
Feeding Rate ◽  
Invasive Alien Species ◽  
Propagule Pressure ◽  
Ecological Impacts ◽  
Economic Damage ◽  
Functional Responses ◽  
Invasion Risk ◽  
Pet Trade

Invasive alien species (IAS) cause myriad negative impacts, such as ecosystem disruption, human, animal and plant health issues, economic damage and species extinctions. There are many sources of emerging and future IAS, such as the poorly regulated international pet trade. However, we lack methodologies to predict the likely ecological impacts and invasion risks of such IAS which have little or no informative invasion history. This study develops the Relative Impact Potential (RIP) metric, a new measure of ecological impact that incorporates per capita functional responses (FRs) and proxies for numerical responses (NRs) associated with emerging invaders. Further, as propagule pressure is a determinant of invasion risk, we combine the new measure of Pet Propagule Pressure (PPP) with RIP to arrive at a second novel metric, Relative Invasion Risk (RIR). We present methods to calculate these metrics and to display the outputs on intuitive bi- and triplots. We apply RIP/RIR to assess the potential ecological impacts and invasion risks of four commonly traded pet turtles that represent emerging IAS: Trachemysscriptascripta, the yellow-bellied slider; T.s.troostii, the Cumberland slider; Sternotherusodoratus, the common musk turtle; and Kinosternonsubrubrum, the Eastern mud turtle. The high maximum feeding rate and high attack rate of T.s.scripta, combined with its numerical response proxies of lifespan and fecundity, gave it the highest impact potential. It was also the second most readily available according to our UK surveys, indicating a high invasion risk. Despite having the lowest maximum feeding rate and attack rate, S.odoratus has a high invasion risk due to high availability and we highlight this species as requiring monitoring. The RIP/RIR metrics offer two universally applicable methods to assess potential impacts and risks associated with emerging and future invaders in the pet trade and other sources of future IAS. These metrics highlight T.s.scripta as having high impact and invasion risk, corroborating its position on the EU list of 49 IAS of Union Concern. This suggests our methodology and metrics have great potential to direct future IAS policy decisions and management. This, however, relies on collation and generation of new data on alien species functional responses, numerical responses and their proxies, and imaginative measures of propagule pressure.

scholarly journals Missing the Boat on Invasive Alien Species: A Review of Post-Secondary Curricula in Canada

1969 ◽  
Vol 41 (1) ◽  
pp. 34-47
Author(s):  
Andrea L. Smith ◽  
Dawn R. Bazely ◽  
Norman D. Yan
Keyword(s):  
Alien Species ◽  
Invasive Alien Species ◽  
Interdisciplinary Approach ◽  
Economic Damage ◽  
Social Scientists ◽  
Post Secondary ◽  
Global Challenge ◽  
Effective Strategies ◽  
Training Professionals ◽  
University Curricula

Invasive alien species (IAS) cause major environmental and economic damage worldwide, and also threaten human food security and health. The impacts of IAS are expected to rise with continued globalization, land use modification, and climate change. Developing effective strategies to deal with IAS requires a collaborative, interdisciplinary approach, in which scientists work co-operatively with social scientists and policy-makers. Higher education can contribute to this process by training professionals to balance the ecological, economic, and social dimensions of the IAS problem. We examined the extent of such training in Canada by reviewing undergraduate and graduate university curricula at all 94 member institutions of the Association of Universities and Colleges of Canada for IAS content. We found that degree and diploma programs focusing on IAS issues are lacking at Canadian post-secondary institutions. Furthermore, few courses are devoted solely to IAS, and those that are typically adopt an ecological perspective. We argue that the absence of interdisciplinary university curricula on IAS in Canada negatively affects our ability to respond to this growing global challenge. We present several international educational programs on IAS as case studies on how to better integrate training on invasive species into university curricula in Canada.

scholarly journals SABANA DI JAWA BALI LOMBOK SERTA KEKUNOAN SABANA BALURAN (Sabana in Java Bali Lombk and Ancient of Baluran Sabana)

2019 ◽  
Vol 11 (1) ◽  
pp. 19-27
Author(s):  
Sutomo ◽  
Eddie van Etten
Keyword(s):  
Alien Species ◽  
Invasive Alien Species ◽  
Climatic Factors ◽  
Floristic Composition ◽  
Fire Regimes ◽  
Lantana Camara ◽  
Acacia Nilotica ◽  
Grass Species ◽  
Eastern Region ◽  
Chromolaena Odorata

Savanna is a type of ecosystem in the lowlands or highlands, where the community consists of several trees that are spread unevenly and the lower layers are dominated by grasses. Savanna is very common in very dry areas in Nusa Tenggara. However, in some places in Java, Savanna can also be found. The widest Savanna in Java is Savanna in Baluran National Park, East Java. Information about the occurrence and formation (composition of vegetation) of Savanna in Indonesia, especially in wet areas, such as Java, Bali and Lombok, is still very rare. This paper compares and distinguishes the characteristics of vegetation from four Savanna (Java - Bali - Lombok) in the ‘wet’ area ‘which has a higher rainfall than the eastern region where savanna is more common in the Indonesian archipelago, to find out what the vegetation features are like can tell us about the origin, maintenance and age of this savanna. The results of this study indicate there are different gradients in elevation (along with related climatic factors such as temperature and rainfall) and fire regimes associated with floristic composition in Savanna Java, Bali and Lombok. Each Savanna is characterized by a variety of different woody and grass species, where Invasive Alien Species (IAS), such as Acacia nilotica, Lantana camara and Chromolaena odorata, are very important in distinguishing between Savanna and other savannas? The characteristics of the species from Savanna Baluran indicate that this ecosystem may be an old Savanna, while other Savanna may be newly formed and their existence is maintained by fire or fire. ABSTRAKSabana adalah tipe ekosistem di dataran rendah atau dataran tinggi yang komunitasnya terdiri atas beberapa pohon yang tersebar tidak merata dan lapisan bawahnya didominasi oleh suku rumput-rumputan. Sabana sangat umum dijumpai di wilayah yang sangat kering di Nusa Tenggara. Meskipun demikian, di beberapa tempat di Pulau Jawa juga dapat dijumpai sabana. Sabana terluas di Pulau Jawa adalah sabana di Taman Nasional Baluran, Jawa Timur. Informasi tentang bagaimana terjadinya serta formasi (komposisi vegetasi) sabana di Indonesia, terutama di daerah basah, seperti Jawa, Bali, dan Lombok, masih sangat jarang. Makalah ini membandingkan dan membedakan karakteristik vegetasi antara empat sabana daerah ‘basah’ di Jawa, Bali, dan Lombok yang memiliki curah hujan lebih tinggi dibanding sabana di kawasan timur Kepulauan Indonesia. Perbandingan ini dilakukan untuk mengetahui fitur vegetasi yang memuat informasi tentang asal-usul, pemeliharaan (maintenance), dan usia sabana ini. Hasil penelitian menunjukkan bahwa terdapat gradien yang berbeda dalam hal elevasi (bersama dengan faktor iklim terkait, seperti suhu dan curah hujan) dan rezim api terkait dengan komposisi floristik di sabana Jawa, Bali, dan Lombok. Setiap sabana dicirikan oleh berbagai spesies berkayu dan rumput yang berbeda yang di dalamnya Invasive Alien Species (IAS), seperti Acacia nilotica, Lantana camara, dan Chromolaena odorata, menjadi jenis yang sangat penting untuk membedakan antara sabana dan sabana yang lain. Karakteristik spesies sabana Baluran menunjukkan bahwa ekosistem ini mungkin merupakan sabana tua, sedangkan sabana yang lain mungkin baru terbentuk dan keberadaannya tetap terpelihara oleh adanya api atau kebakaran.

scholarly journals Assessing the relative potential ecological impacts and invasion risks of emerging and future invasive alien species

NeoBiota ◽  
2018 ◽  
Vol 39 ◽  
pp. 103-126
Author(s):  
James W.E. Dickey ◽  
Ross N. Cuthbert ◽  
Michael Rea ◽  
Ciaran Laverty ◽  
Kate Crane ◽  
...  
Keyword(s):  
Alien Species ◽  
Attack Rate ◽  
Feeding Rate ◽  
Invasive Alien Species ◽  
Propagule Pressure ◽  
Ecological Impacts ◽  
Economic Damage ◽  
Functional Responses ◽  
Invasion Risk ◽  
Pet Trade

Invasive alien species (IAS) cause myriad negative impacts, such as ecosystem disruption, human, animal and plant health issues, economic damage and species extinctions. There are many sources of emerging and future IAS, such as the poorly regulated international pet trade. However, we lack methodologies to predict the likely ecological impacts and invasion risks of such IAS which have little or no informative invasion history. This study develops the Relative Impact Potential (RIP) metric, a new measure of ecological impact that incorporates per capita functional responses (FRs) and proxies for numerical responses (NRs) associated with emerging invaders. Further, as propagule pressure is a determinant of invasion risk, we combine the new measure of Pet Propagule Pressure (PPP) with RIP to arrive at a second novel metric, Relative Invasion Risk (RIR). We present methods to calculate these metrics and to display the outputs on intuitive bi- and triplots. We apply RIP/RIR to assess the potential ecological impacts and invasion risks of four commonly traded pet turtles that represent emerging IAS: Trachemysscriptascripta, the yellow-bellied slider; T.s.troostii, the Cumberland slider; Sternotherusodoratus, the common musk turtle; and Kinosternonsubrubrum, the Eastern mud turtle. The high maximum feeding rate and high attack rate of T.s.scripta, combined with its numerical response proxies of lifespan and fecundity, gave it the highest impact potential. It was also the second most readily available according to our UK surveys, indicating a high invasion risk. Despite having the lowest maximum feeding rate and attack rate, S.odoratus has a high invasion risk due to high availability and we highlight this species as requiring monitoring. The RIP/RIR metrics offer two universally applicable methods to assess potential impacts and risks associated with emerging and future invaders in the pet trade and other sources of future IAS. These metrics highlight T.s.scripta as having high impact and invasion risk, corroborating its position on the EU list of 49 IAS of Union Concern. This suggests our methodology and metrics have great potential to direct future IAS policy decisions and management. This, however, relies on collation and generation of new data on alien species functional responses, numerical responses and their proxies, and imaginative measures of propagule pressure.

scholarly journals The utility of Sentinel-2 Vegetation Indices (VIs) and Sentinel-1 Synthetic Aperture Radar (SAR) for invasive alien species detection and mapping

2019 ◽  
Vol 35 ◽  
pp. 41-61 ◽  
Author(s):  
Perushan Rajah ◽  
John Odindi ◽  
Onisimo Mutanga ◽  
Zolo Kiala
Keyword(s):  
Remote Sensing ◽  
Alien Species ◽  
Invasive Alien Species ◽  
Vegetation Indices ◽  
Cost Effective ◽  
Synthetic Aperture ◽  
Land Use Land Cover ◽  
Alien Plant ◽  
New Generation ◽  
Sentinel 2

The threat of invasive alien plant species is progressively becoming a serious global concern. Alien plant invasions adversely affect both ecological services and socio-economic systems. Hence, accurate detection and mapping of invasive alien species is valuable in mitigating adverse ecological and socio-economic effects. Recent advances in active and passive remote sensing technology have created new and cost-effective opportunities for the application of remote sensing to invasive species mapping. In this study, new generation Sentinel-2 (S2) optical imagery was compared to S2 derived Vegetation Indices (VIs) and S2 VIs fused with Sentinel-1 (S1) Synthetic Aperture Radar (SAR) imagery for detecting and mapping the American Bramble (Rubuscuneifolius). Fusion of S2 VIs and S1SAR imagery was conducted at pixel level and multi-class Support Vector Machine (SVM) image classification was used to determine the dominant land use land cover classes. Results indicated that S2 derived VIs were the most accurate (80%) in detecting and mapping Bramble, while fused S2 VIs and S1SAR were the least accurate (54%). Findings from this study suggest that the application of S2 VIs is more suitable for Bramble detection and mapping than the fused S2 VIs and S1SAR. The superior performance of S2 VIs highlights the value of the new generation S2 VIs for invasive alien species detection and mapping. Furthermore, this study recommends the use of freely available new generation satellite imagery for cost effective and timeous mapping of Bramble from surrounding native vegetation and other land use land cover types.

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