scholarly journals Contrasting effects of exotic plant invasions and managed honeybees on plant–flower visitor interactions

2020 ◽  
Vol 26 (10) ◽  
pp. 1397-1408
Author(s):  
Daria Corcos ◽  
Andree Cappellari ◽  
Maurizio Mei ◽  
Dino Paniccia ◽  
Pierfilippo Cerretti ◽  
...  
Keyword(s):  
Plant Invasions ◽  
Exotic Plant ◽  
Flower Visitor ◽  
Plant Flower

scholarly journals Exotic plant invasions to the mediterranean region of Chile: causes, history and impacts

2004 ◽  
Vol 77 (3) ◽  
Author(s):  
JAVIER A. FIGUEROA ◽  
SERGIO A. CASTRO ◽  
PABLO A. MARQUET ◽  
FABIAN M. JAKSIC
Keyword(s):  
Mediterranean Region ◽  
Plant Invasions ◽  
Exotic Plant ◽  
The Mediterranean

scholarly journals The association of Lantana camara with elephant (Elephas maximus), their food, habitat use and feeding behaviour in southern India

2021 ◽  
Author(s):  
◽  
Gaius Wilson
Keyword(s):  
Habitat Use ◽  
Feeding Behaviour ◽  
Invasive Plant ◽  
Deciduous Forest ◽  
Plant Invasions ◽  
Lantana Camara ◽  
Exotic Plant ◽  
Species Assemblage ◽  
Grass Cover ◽  
Feeding Rates

<p>Invasive exotic species pose an enormous threat to the world's biological diversity. Invasions can alter native communities, replacing local biotas with non-indigenous species introduced by humans. Exotic plant invasions can have negative effects on native flora, which can be in turn detrimental to the herbivores that depend on the vegetation. In this dissertation, I examined the association of an exotic invasive weed, Lantana camara L., with the Asian elephant (Elephas maximus), its food resources (grass and browse), habitat use and feeding behaviour in Mudumalai Tiger Reserve, southern India.  Exotic plant invasions are often associated with alterations or declines in native floral species. I first examined the association of L. camara and measured environmental covariates with floral species assemblage and richness, elephant browse plants, percentage grass cover and percentage grass occupancy. A multivariate analysis revealed a significant association of L. camara with floral species assemblage and richness, some elephant browse plants and grass cover within the moist deciduous forest (MDF) and dry deciduous forest (DDF), but not in the thorn forest (TF) of Mudumalai. My results suggest that L. camara appears to be capable of altering the floral community in some habitats. These results also suggest that changes in the floral community and a reduction in grass cover due to L. camara invasion could be detrimental to elephant and other herbivores that depend on grass in this reserve.   I then examined the association of L. camara with habitat use by elephant. Elephant dung density was used to assess elephant habitat use from 62 line transects, each 1-km in length. I found no evidence that L. camara was associated with elephant habitat use across habitats, although the interaction term between one habitat (DDF) and L. camara was significantly associated with elephant dung density suggesting that the effect of L. camara was different in different habitats. This indicates that L. camara is associated with elephant habitat use within certain habitats. Habitat and impact of human settlements were significantly associated with elephant habitat use across habitats within Mudumalai. In the DDF, however, only L. camara was associated with elephant habitat use. I conclude that while no significant effects of L. camara were seen across habitats, in specific habitats, negative associations of this invasive plant with elephant habitat use, possibly through the reduction of grass cover, are possible. These results indicate that L. camara appears detrimental to elephant in certain habitats and removal of L. camara in these habitats should be prioritised so as to facilitate growth of grass and native browse species, especially if elephant populations continue to expand.  Lastly, I examined the association of elephant behaviour, assessed from feeding and stepping rates, with variation in L. camara invasion. Fifty-seven elephants were observed for a total of 64.3 hours using the focal-animal sampling method. Elephant were never observed to feed on L. camara, but rather fed on grass and browse that were present within and around L. camara patches. Feeding rates (number of trunksful·min⁻¹) were negatively associated with L. camara invasion. A path analysis, which assesses both direct and indirect effects of independent variables, indicated that the total effect of L. camara on feeding rates was 11% less than the direct negative association owing to a positive indirect relationship between L. camara and feeding rates through grass cover and browse density. Lantana camara was not significantly associated with variation in stepping rates (number of steps·min⁻¹). Rather, stepping rates were negatively associated with grass cover and positively associated with browse density. My results indicate that L. camara is potentially capable of changing elephant feeding rates, likely through a loss of grass areas due to L. camara invasion.  Wild elephants do not eat L. camara, and this invasive plant appears to take the place of an important food source. My results indicate that managers should prioritize their focus on certain habitats to control the impact of L. camara on elephants and vegetation. However, this study was of a correlational nature based on observational data. Experimental work is therefore needed to test for causal relationships among the variables I measured, over multiple seasons and in different habitats. Experimental evidence will enhance our understanding of how invasive weeds modify floral communities, elephant habitat use and behaviour and help determine whether L. camara is a 'passenger' or 'driver' of these changes in this ecosystem.</p>

Species Richness Interacts with Drought to Affect Litter Decomposition via its Effect on Litter Nitrogen Concentration

2021 ◽  
Author(s):  
Jiang Wang ◽  
Yuan Ge ◽  
J. Hans C. Cornelissen ◽  
Xiaoyan Wang ◽  
Song Gao ◽  
...  
Keyword(s):  
Species Richness ◽  
Global Change ◽  
Climatic Change ◽  
Litter Decomposition ◽  
Plant Communities ◽  
Nitrogen Concentration ◽  
Plant Invasions ◽  
Exotic Plant ◽  
Ecological Processes ◽  
Litter Nitrogen

Abstract Biodiversity loss, exotic plant invasions and climatic change are currently the three major challenges to our globe and can each affect various ecological processes, including litter composition. To gain a better understanding of global change impacts on ecological processes, these three global change components need to be considered simultaneously. Here we assembled experimental plant communities with species richness levels (1, 2, 4, 8 or 16) and subjected them to drought (no, moderate or intensive drought) and invasion (invasion by the exotic annual plant Symphyotrichum subulatum or not). We collected litter of the native plant communities and let it decompose for nine months within the communities. Drought decreased litter decomposition, while the exotic plant invasion had no impact. Increasing species richness decreased litter decomposition under the mesic condition (no drought), but had little impact under moderate and intensive drought. A structural equation model showed that drought and species richness affected litter decomposition mainly via influencing litter nitrogen concentration, but not via altering the quantity and diversity of soil meso-fauna or soil physio-chemical properties. The negative impact of species diversity on litter decomposition under the mesic condition was mainly ascribed to a sampling effect, i.e. via particularly low litter nitrogen concentrations in the two dominant species. Our results indicate that species richness can interact with drought to affect litter decomposition via effect on litter nitrogen. We conclude that nitrogen-dependent litter decomposition should be a mechanism to predict integrated effects of plant diversity loss, exotic plant invasions and climatic change on litter decomposition.

Woody exotic plant invasions and fire: reciprocal impacts and consequences for native ecosystems

2011 ◽  
Vol 13 (8) ◽  
pp. 1815-1827 ◽  
Author(s):  
Lisa Mandle ◽  
Jennifer L. Bufford ◽  
Isabel B. Schmidt ◽  
Curtis C. Daehler
Keyword(s):  
Plant Invasions ◽  
Exotic Plant

Roads as Conduits for Exotic Plant Invasions in a Semiarid Landscape

2003 ◽  
Vol 17 (2) ◽  
pp. 420-432 ◽  
Author(s):  
Jonathan L. Gelbard ◽  
Jayne Belnap
Keyword(s):  
Plant Invasions ◽  
Exotic Plant

Post-fire seeding with ryegrass: implications for understorey plant communities and overall effectiveness

2015 ◽  
Vol 24 (4) ◽  
pp. 518
Author(s):  
Melissa A. McMaster ◽  
Andrea Thode ◽  
Michael Kearsley
Keyword(s):  
Ponderosa Pine ◽  
Plant Cover ◽  
Ground Cover ◽  
Plant Invasions ◽  
Bare Soil ◽  
Italian Ryegrass ◽  
Exotic Plant ◽  
Vegetative Cover ◽  
High Severity ◽  
Significant Difference

Seeding following high-severity wildfires is motivated by the goals of increasing vegetative cover and decreasing bare soil in order to minimise soil erosion and exotic plant invasions. We compared the ground cover and vegetation response of seeded versus non-seeded areas located in the Warm Fire in northern Arizona, where post-fire seeding treatments with Italian ryegrass (Lolium perenne spp. multiflorum (L.)) were conducted in 4000 ha of high-severity burned areas. Over the course of the study, we observed no significant difference between seeded and non-seeded plots in percentage of bare soil, total vegetative cover or exotic plant cover. However, there were significant differences in plant community composition as revealed by PERMANOVA and Indicator Species Analysis. Two years post-fire there were significantly fewer ponderosa pine seedlings, and the cover of annual and biennial forbs was significantly lower in plots that were seeded with Italian ryegrass. In the third year, the cover of native bunch grasses was significantly lower in seeded plots. The differences we observed may be due to differences in pre-existing vegetation composition because of the geographic separation of the plots across the landscape. Our results illustrate the ineffectiveness of post-fire seeding in achieving the goals of increasing vegetative cover and decreasing the invasion of non-native plants, and we suggest that alternative post-fire remediation should be considered in the future.

The structure of a high latitude plant-flower visitor system: the dominance of flies

Ecography ◽  
1999 ◽  
Vol 22 (3) ◽  
pp. 314-323 ◽  
Author(s):  
Heidi Elberling ◽  
Jens M. Olesen
Keyword(s):  
High Latitude ◽  
Flower Visitor ◽  
Plant Flower

scholarly journals Moderation is best: effects of grazing intensity on plant-flower visitor networks in Mediterranean communities

2016 ◽  
Vol 26 (3) ◽  
pp. 796-807 ◽  
Author(s):  
Amparo Lázaro ◽  
Thomas Tscheulin ◽  
Jelle Devalez ◽  
Georgios Nakas ◽  
Anastasia Stefanaki ◽  
...  
Keyword(s):  
Grazing Intensity ◽  
Flower Visitor ◽  
Plant Flower ◽  
Mediterranean Communities
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