The native - exotic plant choice in green roof design: using a multicriteria decision framework to foster urban biodiversity

Green roofs are considered key elements of the urban green infrastructure since they offer several environmental benefits, including habitat provision for arthropods. To achieve these benefits and ensure green roof success, an appropriate plant selection is an important step in the design of these infrastructures, especially where green roof technology is emerging like in South American cities. So far, decisions of using native or exotic plant species in green roofs had never been evaluated taking into account the plant potential to foster beneficial arthropods. By applying an integrative multicriteria decision framework that combined the habitat template hypothesis with the potential of plants to attract floral visitors and natural enemies, we obtained a ranked set of candidate native and exotic plant species. Among the best-ranked candidate species, we further compared the performance of six native and six exotic species in 30 experimental green roofs installed in Cordoba city, Argentina. To evaluate plant success, the occurrence and cover of each species were recorded one year after establishment under two management conditions: regular watering and weeding of spontaneous plants, and no management (15 roofs each). All selected species increased their vegetative cover one year after establishment. More interestingly, native plants had an advantage over exotic plant species as they exhibited a significantly higher occurrence and a slightly higher cover with no management than exotics. Native annuals were able to reseed the following season even in the absence of management, thus highlighting the relative importance of lifespan as a useful plant trait for future studies in green roof design. Given that green roofs are one of the possible solutions to ameliorate the negative effects of urban habitat loss on arthropod diversity, the development of an integrative multicriteria decision framework that takes into account the potential of native and exotic plant species for promoting beneficial arthropods would give a new twist in plant selection processes for green roofs.

Invasive exotic plant monitoring at Dinosaur National Monument: Results of the 2019 field season on the Green River, and the third completed monitoring rotation

Invasive exotic plant (IEP) species are a significant threat to natural ecosystem integrity and biodiversity, and controlling them is a high priority for the National Park Service. The Northern Colorado Plateau Network (NCPN) selected the early detection of IEPs as one of 11 monitoring protocols to be implemented as part of its long-term monitoring program. We also calculated a patch management index (PMI) to quantify the extent and density of invasive patches into a single value that helps identify the scale of the problem. Park managers can use this tool to help prioritize IEP treatment. At Dinosaur National Monument, the NCPN monitors IEPs in the Green and Yampa river corridors. This report summarizes data from monitoring on the Green River in 2019, and monitoring on the Yampa River in 2017, to represent the completion of the third monitoring rotation of the entire river corridor (2002–2005, 2010–2011, 2017–2019). During surveys conducted from June 26 to July 2, 2019, NCPN staff detected 12 priority IEP species and two non-priority species in a 84.6-hectare (209-acre) area along 74.4 kilometers of the Green River above (“upper”) and below (“low-er”) its confluence with the Yampa. A total of 2,535 IEP patches were detected. Of those patches, 24.2% and 15.6% were smaller than 40 m2 on the upper and lower Green River reaches, respectively. The patch management index (PMI) was low or very low for 95.7% of patches on the upper Green River and 90.9% of patches on the lower Green River. Tamarisk (Tamarix sp.), broad-leaf pepperwort (Lepidium latifolium), and yellow sweetclover (Meli-lotus officinalis) were the most widespread species. For the first time, NCPN monitoring detected teasel (Dipsacus sylvestris) on the upper Green River. Yellow sweetclover has increased on all three river reaches during the survey years. Musk thistle (Carduus nutans) was found at considerably lower levels than yellow sweetclover but has also increased on all three river reaches. Leafy spurge is increasing on the lower Green River and Yampa River. Cheatgrass was not monitored in the first rotation, but increased substantially in cover and percent frequency on all three river sections from 2010–2011 to 2017–2019. This increase may be due to a lack of recent high-flow scouring events. The highly regulated upper Green River generally has the highest number of IEPs, while the lower Green River has a moderate amount of IEPs. The largely unregulated flows of the Yampa River continue to result in a lower number of patches per kilometer, lower percent cover, and lower percent frequency than the upper or lower Green River. Network staff will return to the monument in 2022 to begin the fourth monitoring rotation.

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

<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>

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

<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>

Review of Existing Knowledge and Practices of Tarping for the Control of Invasive Knotweeds

Managing invasive exotic plant species is a complex challenge, especially for Asian knotweeds (Reynoutria spp.). Tarping is a regularly cited but poorly documented control method, which consists of covering the ground with a tarp (agricultural tarp, geotextile, geomembrane, etc.) to create a physical barrier to hinder plant growth and deprive the plants of light in order to deplete their rhizomatous reserves. To improve our knowledge of tarping in order to identify the key factors of its success or failure, we reviewed the relevant grey and scientific literature and conducted an international survey among managers to collect feedback on tarping experiments. In the literature, as well as in the field, practices are quite heterogeneous, and the method’s effectiveness is highly contrasted. A better consideration of knotweed biology may improve the efficacy of the method. Based on the bibliography and survey work, we propose practical recommendations including covering the entire stand, extending the tarping up to 2.5 m beyond its edges for a period of at least six years, and ensuring regular monitoring. Even though tarping does not seem to be a one-size-fits-all solution to eradicate knotweed, it could still be a useful control method once knotweed has become a critical management issue.

Prescribed versus wildfire impacts on exotic plants and soil microbes in California grasslands

1. Prescribed fire is often used as a management tool to decrease exotic plant cover and increase native plant cover in grasslands. These changes may also be mediated by fire impacts on soil microbial communities, which drive plant productivity and function. Yet, the ecological effects of prescribed burns compared to wildfires on either plant or soil microbial composition remain unclear. 2. Here, we investigated the impacts of a spring prescribed fire versus a fall wildfire on plant cover and community composition and bacterial and fungal richness, abundance, and composition in a California grassland. We used qPCR of 16S and 18S to assess impacts on bacterial and fungal abundance and Illumina MiSeq of 16S and ITS2 to assess impacts on bacterial and fungal richness and composition. 3. Wildfire had stronger impacts than prescribed fire on microbial communities and both fires had similar impacts on plants with both prescribed and wildfire reducing exotic plant cover but neither reducing exotic plant richness. Fungal richness declined after the wildfire but not prescribed fire, but bacterial richness was unaffected by either. Yet increasing char levels in both fire types resulted in reduced bacterial and fungal biomass, and both fire types slightly altered bacterial and fungal composition. 4. Exotic and native plant diversity differentially affected soil microbial diversity, with native plant diversity leading to increased arbuscular mycorrhizal fungal richness while exotic plant diversity better predicted bacterial richness. However, the remainder of the soil microbial communities were more related to aspects of soil chemistry including cation exchange capacity, organic matter, pH and phosphorous. 5. Synthesis and applications. Understanding the different ecological effects of prescribed fires and wildfires on plant and soil communities are key to enhancing a prevalent management action and to guide potential management opportunities post wildfires. Our coupled plant and soil community sampling allowed us to capture the sensitivity of the fungal community to fire and highlights the importance of potentially incorporating management actions such as soil or fungal amendments to promote this critical community that mediates native plant performance.

Levoglucosan Emission From Different Indigenous and Exotic Plant Species in Bangladesh

Levoglucosan is a biomarker for biomass burning with high emission efficiency. Both indigenous and exotic plant species (biomass) are common in Bangladesh and used as a fuel source in rural areas for cooking purposes. Three indigenous plants, Mango (Mangifera indica), Jackfruit (Artocarpus heterophyllus), Coconut (Cocos nucifera) and three exotic plants, Mahogany (Swietenia mahagoni), Koroi (Albizia lebbeck), Guava (Psidium guajava), were selected for this experiment. The study was carried out to determine and compare the levoglucosan emission for these selected indigenous and exotic plants upon burning at the typical rural cooking stove in the laboratory scale. PM10 samples were collected on top of the cooking stove using a low volume air sampler (LVAS). The concentration was determined quantitatively by UV-visible spectrophotometer using anthrone-sulfuric acid reagent. The exotic plant samples (7.47 mg/m3) emitted a higher concentration of levoglucosan than the indigenous plant samples (6.49 mg/m3). Among the six different leaf samples, S. mahagoni leaves showed the highest emission of levoglucosan (6.31 mg/m3) and C. nucifera leaves showed the lowest levoglucosan (5.74 mg/m3) due to their individual cellulose content and combustion efficiency. Among the six wood samples, S. mahagoni woods showed the maximum concentration (9.63 mg/m3) and C. nucifera coir showed the minimum concentration (6.631 mg/m3) of levoglucosan emission. The soft leaf samples (6.02 mg/m3) showed lower emission than the hardwood (7.97 mg/m3) samples because of their diverse structural pattern and combustion efficiency. Comparing the emission factors, the exotic wood and leaf samples (EF=2.89*10– 3g/kg) showed higher emission than the indigenous wood and leaf samples (EF=2.55*10–3g/kg) J. Biodivers. Conserv. Bioresour. Manag. 2020, 6(2): 1-10

Panini’s Astadhyayi in the Eyes of Plant Invasion on Indian Subcontinent

Indigenous plantlore is a manifestation in a given community, based on adaptation and wisdom of local people and environment. It develops over times and continues so also. This treasure of traditional knowledge is used to sustain the community and its bioculture. In long past, people of great understanding, christalized their wisdom in some treatises such as the Panini’s Astadhyayi. This treatise is understood and well known for the genesis and development of Sanskrit knowledge. Ancient Sanskrit scripts usually contain information concerning culture and sustenance based on plant world. The present author analysed it in view of plant invasion on Indian landmass in Panini’s time. Total 45 exotic plant species belonging to 44 genera and 29 angiospermic families are divulged from it. These belong to nearly all corners of the Old and New Worlds. Majority of them (28 species) are cultigens and still continue even in modern period in India. Of course, rest of them are wild, naturalised and presently constitute integral part of Indian biodiversity. The importance of such ancient treatises is dilated in this communication.