Invasive Exotic Plant Species Research Articles

Growth of the Aquatic Plant Southern Naiad in Varying Percentages of Sand and Controlled-release Fertilizer

Native aquatic plants are important to maintaining a balanced ecosystem, but they often are displaced by exotic invasive plant species. The research on the control and growth of the invasive aquatic species hydrilla (Hydrilla verticillata) using sand substrates and controlled-release fertilizers (CRF) provides a potential production technique for other aquatic plants. We questioned if we could use hydrilla production techniques to grow southern naiad (Najas guadalupensis), a Florida-native aquatic plant that is often mistaken for hydrilla. We grew southern naiad cuttings in containers filled with 100:0, 75:25, 50:50, 25:75, or 0:100 coarse builder’s sand and sphagnum moss (by volume). Before planting, containers were fertilized with 0, 1, 2, or 4 g·kg−1 CRF (15N–4P–10K). Containers were submerged in large storage tubs filled with rainwater and grown for 8 weeks. Southern naiad shoot dry weight was greater in the 100% sand substrate than that in the 0% sand substrate. Substrate electrical conductivity (EC) levels were greater in the 0% sand with no difference among the other substrates. Shoot and root dry weight of plants fertilized with 1–2 g·kg−1 CRF were greater than 0 or 4 g·kg−1 CRF. Substrate EC also increased as fertilizer rate increased, with the highest EC observed at 4 g·kg−1 CRF. Based on our results, we would suggest growing southern naiad in substrates with 100% sand and fertilized with 1–2 g·kg−1 CRF.

Invasive plant species thresholds in the forests of Robinson Crusoe Island, Chile

ABSTRACTBackground: Invasion by exotic plants worldwide can lead to the loss of native species, particularly on islands with a high proportion of endemic plants, such as Robinson Crusoe Island (RCI).Aims: We studied the two most invasive exotic plant species occurring in the forest of RCI: Aristotelia chilensis and Rubus ulmifolius. We aimed at establishing thresholds for environmental and microsite variables related to invasion.Methods: Environmental and forest understorey variables, including canopy gaps and invasive species cover were measured in non-invaded and invaded forest sites. We expected more invasion in plots located close to invasive shrublands, and in large gaps with high solar radiation.Results: We found no relationship between the distance to invasive shrublands and invasion probability. Solar radiation tended to be slightly related with a higher cover of R. ulmifolius, the most abundant invasive exotic plant in RCI forests. Overall, the cover of native ferns appeared to inhibit invasion.Conclusions: The identification of variable thresholds related to invasion can be useful for guiding management decisions. Our results suggest that management should consider monitoring forest canopy gap formation and promote the establishment of ferns to reduce the probability of invasive species establishing.

Effects of exotic-native species relationship on naturalization and invasion of exotic plant species

Effects of exotic-native species relationship on naturalization and invasion of exotic plant species

Invasion of <i>Cestrum aurantiacum</i> Lindl. in Kenya

Many forest ecosystems in Kenya are at risk from the invasion of exotic plant species that pose numerous threats like decreasing biodiversity, deteriorating ecosystem processes and degrading their services. They also affect human, other animal health and various angles of the general economy. Cestrum aurantiacum Lindl. is a species with invasive reputation having been reported with very high biological success rating and has been noted in parts of Kenya in proportions that raise concerns. It has negative effects on other plants and animal species function and diversity. These impacts have been recorded in Kenya and elsewhere in this review, I synthesized data from studies that have examined the taxonomy of Cestrum aurantiacum, how this species become part of the ecosystem in Kenya and its ecological and economic impacts. I sourced relevant articles from the internet using keywords relating to the taxonomy, impacts and reports of invasive species and narrowed to records from different parts of Kenya. In this review, I looked across twenty-seven studies, on Cestrum aurantiacum in Kenya and went ahead to review one hundred and thirteen other articles for expanded discussion. Species data in published articles from different parts of Kenya were used as georefences to model overall species distribution which was noted to lie between Mt Kenya, Mt Elgon-Nandi hills and Cherangani hills. It was clearly established that there are major adverse effects associated with species. First, it can change native ecosystem processes such as nutrient cycle or hydrology and contribute significant role on the decrease of native species. A primary risk of Cestrum aurantiacum is that when this species alters the biodiversity, ecosystems are transformed into new configurations with unpredictable consequences to humans and other wildlife in totality. Despite the few positive applications of cestrum species, these can’t compensate for the enormous detrimental consequences associated with the species. Cestrum aurantiacum was introduced in Kenya as an ornamental plant in 1921 by the government and was distributed in several regions of high potential Kenya due to high level of hybridization within the genera, several variables of the species occur. By examining the level of information regarding the taxonomy and impacts of Cestrum aurantiacum on animal and plant species, this study provides pivotal information at the country level with a view to informing monitoring and conservation efforts, such as alien plant removal and control programmes, and ensuring that endemic terrestrial animal and plant diversity are maintained.

Elevated carbon dioxide and warming impact silicon and phenolic-based defences differently in native and exotic grasses.

Global climate change may increase invasions of exotic plant species by directly promoting the success of invasive/exotic species or by reducing the competitive abilities of native species. Changes in plant chemistry, leading to altered susceptibility to stress, could mediate these effects. Grasses are hyper-accumulators of silicon, which play a crucial function in the alleviation of diverse biotic and abiotic stresses. It is unknown how predicted increases in atmospheric carbon dioxide (CO2 ) and air temperature affect silicon accumulation in grasses, especially in relation to primary and secondary metabolites. We tested how elevated CO2 (eCO2 ) (+240ppm) and temperature (eT) (+4°C) affected chemical composition (silicon, phenolics, carbon and nitrogen) and plant growth in eight grass species, either native or exotic to Australia. eCO2 increased phenolic concentrations by 11%, but caused silicon accumulation to decline by 12%. Moreover, declines in silicon occurred mainly in native species (-19%), but remained largely unchanged in exotic species. Conversely, eT increased silicon accumulation in native species (+19%) but decreased silicon accumulation in exotic species (-10%). Silicon and phenolic concentrations were negatively correlated with each other, potentially reflecting a defensive trade-off. Moreover, both defences were negatively correlated with plant mass, compatible with a growth-defence trade-off. Grasses responded in a species-specific manner, suggesting that the relative susceptibility of different species may differ under future climates compared to current species rankings of resource quality. For example, the native Microlaena stipoides was less well defended under eCO2 in terms of both phenolics and silicon, and thus could suffer greater vulnerability to herbivores. To our knowledge, this is the first demonstration of the impacts of eCO2 and eT on silicon accumulation in grasses. We speculate that the greater plasticity in silicon uptake shown by Australian native grasses may be partly a consequence of evolving in a low nutrient and seasonally arid environment.

Have your cake and eat it too: greater dispersal ability and faster germination towards range edges of an invasive plant species in eastern Australia

The process of range expansion often selects for traits that maximize invasion success at range edges. For example, during range expansion, individuals with greater dispersal and colonization ability will be selected for towards range edges. For wind dispersed plants, however, there exists a fundamental trade-off between dispersal and colonization ability (germination success and growth) that is mediated by seed size; smaller seeds often have greater dispersal ability but poorer colonization ability. We investigated the nature of the dispersal/colonization trade-off by comparing dispersal ability (wing loading ratio: seed mass/wing area), germination success and growth related traits across multiple populations of a coastal exotic invasive plant species (Gladiolus gueinzii Kunze) along its entire introduced distribution in eastern Australia. We found that G. gueinzii had significantly greater dispersal ability towards its range edges which was mediated by a decrease in seed mass. However, this was not associated with a decrease in probability of germination or growth after 3 months. In fact, seeds from range edge populations had significantly faster germination times. Our results suggest that a shift towards greater dispersal ability does not have an associated negative effect on the colonization ability of G. gueinzii and may be a key factor in promoting further range expansion of this exotic invasive species.

Invasive Exotic Plant Species—Major Threats to the Wetland Ecosystem in the Everglades

Invasive Exotic Plant Species—Major Threats to the Wetland Ecosystem in the Everglades

Non‐target impacts of weed control on birds, mammals, and reptiles

AbstractThe impacts of invasive plant control on native animals are rarely evaluated. Using data from an eight‐year study in southeastern Australia, we quantified the effects on native bird, mammal, and reptile species of (1) the abundance of the invasive Bitou Bush, Chrysanthemoides monilifera ssp. rotundata, and (2) a Bitou Bush control program, which involved repeated herbicide spraying interspersed with prescribed burning. We found that overall species richness of birds, mammals, and reptiles and the majority of individual vertebrate species were unresponsive to Bitou Bush cover and the number of plants. Two species including the nationally endangered Eastern Bristlebird (Dasyurus brachypterus) responded positively to measures of native vegetation cover following the control of Bitou Bush. Analyses of the effects of different components of the treatment protocol employed to control Bitou Bush revealed (1) no negative effects of spraying on vertebrate species richness; (2) negative effects of spraying on only one individual species (Scarlet Honeyeater); and (3) lower bird species richness but higher reptile species richness after fire. The occupancy of most individual vertebrates species was unaffected by burning; four species responded negatively and one positively to fire. Our study indicated that actions to remove Bitou Bush generally have few negative impacts on native vertebrates. We therefore suggest that controlling this highly invasive exotic plant species has only very limited negative impacts on vertebrate biota.

Do forest soil microbes have the potential to resist plant invasion? A case study in Dinghushan Biosphere Reserve (South China)

Successful invaders must overcome biotic resistance, which is defined as the reduction in invasion success caused by the resident community. Soil microbes are an important source of community resistance to plant invasions, and understanding their role in this process requires urgent investigation. Therefore, three forest communities along successional stages and four exotic invasive plant species were selected to test the role of soil microbes of three forest communities in resisting the exotic invasive plant. Our results showed that soil microbes from a monsoon evergreen broadleaf forest (MEBF) (late-successional stage) had the greatest resistance to the invasive plants. Only the invasive species Ipomoea triloba was not sensitive to the three successional forest soils. Mycorrhizal fungi in early successional forest Pinus massonina forest (PMF) or mid-successional forest pine-broadleaf mixed forest (PBMF) soil promoted the growth of Mikania micrantha and Eupatorium catarium, but mycorrhizal fungi in MEBF soil had no significant effects on their growth. Pathogens plus other non-mycorrhizal microbes in MEBF soil inhibited the growth of M. micrantha and E. catarium significantly, and only inhibited root growth of E. catarium when compared with those with mycorrhizal fungi addition. The study suggest that soil mycorrhizal fungi of early-mid-successional forests benefit invasive species M. micrantha and E. catarium, while soil pathogens of late-successional forest may play an important role in resisting M. micrantha and E. catarium. The benefit and resistance of the soil microbes are dependent on invasive species and related to forest succession. The study gives a possible clue to control invasive plants by regulating soil microbes of forest community to resist plant invasion.

Spatial modelling of congruence of native biodiversity and potential hotspots of forest invasive species (FIS) in central Indian landscape

The tropical forest ecosystems across the globe are under major threats from spread of exotic invasive plant species. Identification of biodiversity rich areas prone to large-scale plant invasion and their prioritisation is vital for targeting prevention and control programmes. Recent availability of field inventoried forest native and forest invasive species (FIS) data from a nation-wide biodiversity project in India, has served as a valuable source of information for conservation prioritization. Our approach considers prioritisation of phytogeographic areas based on congruence of spatial pattern of phytorichness distribution and spatial pattern of potential spread of hotspots of multiple FIS. We modelled native phytorichness at landscape scale following a three-tier methodology of mapping of habitat types, field sampling of vascular plants and spatial modelling with landscape matrices for central Indian landscape in India. The hotspots of multiple FIS were modelled with occurrences of 98 species, and optimally chosen environmental covariates using MaxEnt. We then integrated phytorichness and FIS invasion hotspots information to identify priority zones (high, medium and low) for informed policy decisions for conservation actions. Study emphasises that potential hotspots of invasive species should be considered for conservation priority setting.

Identifying invasive plant species using field spectroscopy in the VNIR region in successional systems of north-central Virginia

ABSTRACTRemote sensing can potentially be used to monitor the extent and distribution of invasive species across landscapes and regions, thus aiding conservation efforts. We collected ground-level hyperspectral data of six exotic invasive plant species in abandoned agricultural fields at the Blandy Experimental Farm in northern Virginia to determine the degree to which species could be identified using visible and near-infrared wavelengths. The spectral profile from 350 to 1025 nm was used in support vector machine analysis to determine separability of these species. We used sensitivity analyses to determine which spectral regions were most influential to identifying species by removing 50 nm regions and comparing species identification to that using the full spectral profile. Ailanthus altissima, Carduus acanthoides, and Cirsium arvense had high ability to be identified (75%, 87.5%, and 75%, respectively). Galium verum had low ability to be identified (44.4%), perhaps due to high spectral contamination from soil. Celastrus orbiculatus and Rhamnus davurica had low ability to be identified (27.3% and 30.8%, respectively); however, they were often misclassified as each other, due to their physical overlap in the field. The sensitivity analysis revealed that the 350–399, 500–549, 700–749, and 900–949 nm regions were most useful for species identification, while 550–599 and 650–699 nm regions were detrimental, perhaps due to greater intraspecific variability than interspecific variability in these regions. These most influential regions for identification were similar to those found in other studies. Thus, it is possible to identify species using ground-level hyperspectral data.

Alteration of hydrogeomorphic processes by invasive beavers in southern South America

The North American beaver (Castor canadensis) is an invasive species in southern Patagonia, introduced in 1946 as part of a program by the Argentine government to augment furbearers. Research focus has turned from inventorying the beaver's population and ecosystem impacts toward eradicating it from the region and restoring degraded areas. Successful restoration, however, requires a fuller determination of how beavers have altered physical landscape characteristics, and of what landscape features and biota need to be restored. Our goal was to identify changes to the physical landscape by invasive beaver. We analyzed channel and valley morphology in detail at one site in each of the three major forest zones occurring on the Argentine side of Tierra del Fuego's main island. We also assessed 48 additional sites across the three forest biomes on the island to identify a broader range of aquatic habitat occupied and modified by beaver. Beaver build dams with Nothofagus tree branches on streams, which triggered mineral sediment accretion processes in the riparian zone, but not in ways consistent with the beaver meadow theory and only at a few sites. At the majority of sites, beavers actively excavated peat and mineral sediment, moved thousands of cubic meters of sediment within their occupied landscapes and used it to build dams. Beaver were also common in fen ecosystems where pond formation inundated and drowned peat forming mosses and sedges, and triggered a massive invasion of exotic plant species. Results highlight that restoration of fen ecosystems is a previously unrecognized but pressing and challenging restoration need in addition to reforestation of Nothofagus riparian forests. We recommend that decision-makers include the full ecosystem diversity of the Fuegian landscape in their beaver eradiation and ecosystem restoration plans.

Vegetation structure and composition in the semi-arid Mapungubwe Cultural Landscape

235 ABSTRACT: Mapungubwe Cultural Landscape (MCL) woody vegetation was characterized to establish structural and compositional attributes. Stratified random sampling based on major soil types was used and nine plant variables were measured in 137(20x30) m 2 sampling plots; these being genera, species and family names; basal circumference; plant height; depth and diameter of tree canopy; number of stems per plant; plant life status; number of trees and shrubs; and number of saplings. A total of 3114 woody plants were sampled, comprising an assemblage of 28 families, 63 genera and 106 species. The results suggest alluvial floodplain flanking the Limpopo River is a biodiversity hotspot with high plant species diversity (H �=1.8-2.2) 1/ha, taller trees (P<0.05) with median height per plot ranging between 6.1-10 m, high canopy volume at 105783 (443155m 3 /ha) and basal area (16.9-111m 2 /ha). The Arenosols-Regosol stratum had significantly shorter trees (P<0.05) with median height per plot between 3-4 m, low species diversity (H �=0.8-2.3) 1/ha, low basal area (3.23-48.2m 2 /ha) and low canopy volume (6687.08(155965.00) m 3 /ha. The Cambisol- Luvisol stratum in the western section of MCL had high number of stems/plant at 1.65 (1.40), high woody plant density 483.33 (900.00) 1/ha, F 3,137 =19.07,P<0.05), high density of dead plants 16.67 (133.30) 1/ha and high sapling density 208.33 (850.00) 1/ha. The present study suggests soil type is a key determinant of woody vegetation structure and composition. The study recommends regular vegetation monitoring, periodic update of plant species inventories in protected areas, control of exotic invasive woody plant species found along the Limpopo river floodplain within the biodiversity management framework of Greater Mapungubwe Transfrontier Conservation Area initiative.

The US Wilderness Managers Survey: Charting a Path for the Future

The Wilderness Manager Survey (WMS) was developed in 2014 to support interagency strategic planning for the National Wilderness Preservation System (NWPS) and asked managers about their perceived threats to the NWPS, the need for science information to support decisionmaking, the need for education and training, and the most important problems for managers in the future. The WMS was administered during Feb. 24 to May 19, 2014, to wilderness managers in the four federal agencies who manage the lands of the NWPS, and 368 wilderness managers responded. The important external and internal threats as perceived by managers for the NWPS for the next 20 years were the following: the lack of political and financial support for wilderness protection and management, invasive exotic plant or animal species, disconnected urban audiences unaware of wilderness, adjacent land management and incompatible uses, and legislation designating wilderness that included compromised natural conditions or incompatible special provisions for management.

Long-Term Effects of White-Tailed Deer Exclusion on the Invasion of Exotic Plants: A Case Study in a Mid-Atlantic Temperate Forest.

Exotic plant invasions and chronic high levels of herbivory are two of the major biotic stressors impacting temperate forest ecosystems in eastern North America, and the two problems are often linked. We used a 4-ha deer exclosure maintained since 1991 to examine the influence of a generalist herbivore, white-tailed deer (Odocoileus virginianus), on the abundance of four exotic invasive (Rosa multiflora, Berberis thunbergii, Rubus phoenicolasius and Microstegium vimineum) and one native (Cynoglossum virginianum) plant species, within a 25.6-ha mature temperate forest dynamics plot in Virginia, USA. We identified significant predictors of the abundance of each focal species using generalized linear models incorporating 10 environmental and landscape variables. After controlling for those predictors, we applied our models to a 4-ha deer exclusion site and a 4-ha reference site, both embedded within the larger plot, to test the role of deer on the abundance of the focal species. Slope, edge effects and soil pH were the most frequent predictors of the abundance of the focal species on the larger plot. The abundance of C. virginianum, known to be deer-dispersed, was significantly lower in the exclosure. Similar patterns were detected for B. thunbergii, R. phoenicolasius and M. vimineum, whereas R. multiflora was more abundant within the exclosure. Our results indicate that chronic high deer density facilitates increased abundances of several exotic invasive plant species, with the notable exception of R. multiflora. We infer that the invasion of many exotic plant species that are browse-tolerant to white-tailed deer could be limited by reducing deer populations.

Biodiversity conservation through totem, taboo and magico-religious beliefs in the eastern Himalaya of India: an ethno botanical study

The present article deals with the documentation of plant species used by local tribes of one of the biggest districts in eastern Himalayan region of India for totem, taboo, avoidance and magico-religious purposes. In total, 72 plant species belonging to 28 families were recorded in the study area of Upper Subansiri District of Arunachal Pradesh. Dioscoreaceae, Poaceae and Araceae were the dominant families with 15, 7 and 6 plant species respectively. Some local issues like encroachments, forest fires, over exploitation, habitat destruction, lack of plantation and regeneration activities in time and invasion of exotic plant species, which require the State Government's immediate attention for overall conservation of forests of the region, have been discussed in the article.

Biodiversity conservation through totem, taboo and magico-religious beliefs in the eastern Himalaya of India: an ethno botanical study

The present article deals with the documentation of plant species used by local tribes of one of the biggest districts in eastern Himalayan region of India for totem, taboo, avoidance and magico-religious purposes. In total, 72 plant species belonging to 28 families were recorded in the study area of Upper Subansiri District of Arunachal Pradesh. Dioscoreaceae, Poaceae and Araceae were the dominant families with 15, 7 and 6 plant species respectively. Some local issues like encroachments, forest fires, over exploitation, habitat destruction, lack of plantation and regeneration activities in time and invasion of exotic plant species, which require the State Government's immediate attention for overall conservation of forests of the region, have been discussed in the article.

Semi-parametric Geographically Weighted Regression (S-GWR): a Case Study on Invasive Plant Species Distribution in Subtropical Nepal

GIScience 2016 Short Paper Proceedings Semi-parametric Geographically Weighted Regression (S- GWR): a Case Study on Invasive Plant Species Distribution in Subtropical Nepal Qunshan Zhao 1 , Elizabeth A. Wentz 1 , Stewart Fotheringham 1 , Scott T. Yabiku 2 , Sharon J. Hall 3 , Jennifer E. Glick 2 , Jie Dai 4 , Michele Clark 3 , Hannah Heavenrich 3 Center for Geographical Information Science, School of Geographical Sciences and Urban Planning, Arizona State University, Tempe, AZ 85287, USA Email: {qszhao; wentz; sfotheri}@asu.edu Department of Sociology and Criminology, Pennsylvania State University, University Park, PA 16802, USA Email: {sty105; jeg115}@psu.edu School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA Email: {sharonjhall; mdclar10; hheavenr}@asu.edu Department of Geography, San Diego State University, San Diego, CA 92182, USA Email: jdai@rohan.sdsu.edu Abstract Geographically weighted regression (GWR) is a spatial statistical methodology to explore the impact of non-stationarity on the interaction between spatially measured dependent and inde- pendent variables. In this paper we use a semi-parametric geographically weighted regression (S- GWR) and demonstrate the effectiveness of the method on a case study on socio-ecological fac- tors on forest vulnerability. The case study is based on community forests in and around the buffer zone of Chitwan National Park, Nepal, a biodiversity hotspot that is being rapidly degrad- ed by exotic invasive plant species. This research integrated heterogeneous data sources such as observational ecological surveys, household interviews, and remotely sensed imagery. These data were utilized to extract and represent invasive plant species coverage, human activity inten- sity, topographical parameters and vegetation greenness indices. Research findings both demon- strate the S-GWR method and offer possible interventions that could slow the catastrophic spread of invasive plant species in Chitwan, Nepal. 1. Introduction Geographically weighted regression (GWR) is a spatial analysis method that uses the spatial dis- tribution of dependent and independent variables to specify non-stationarity to quantify the driv- ers of spatially dependent processes. GWR has been widely applied in application domains such as species distribution modeling in ecology and crime analysis in sociology (Foody 2004; Zhang and Song 2013). This paper presents a semi-parametric geographically weighted regression (S- GWR) method to model the factors that influence the spatial distribution of invasive plants in Nepal. We chose to use a semi-parametric model to include both parametric and non-parametric variables in the model specification. The S-GWR is implemented in a case study on the relation- ship between socio-ecological factors and invasive plant species in Chitwan, Nepal. Invasive plant species are considered as a serious global environmental threat to ecosystem structure and function by creating disturbances in ecosystems, reducing native species diversity and abundance, limiting human usage of ecosystems and triggering environmental changes. It is an emergent research topic to prevent invasive plant species spread and alleviate their influences in forest ecosystems. The case study aims to quantify the relationships between invasive plant species coverage and socio-ecological factors in community forests (CFs) in Chitwan, Nepal. We

Spatial patterns and determinants of species richness of alien and native plants in the Nujiang River valley

Biological invasion has attracted widespread attention because invasive species threaten native biodiversity and weaken ecosystem services. Based on field investigation of vegetation in Nujiang River valley, Northwest Yunnan, we analyzed the spatial patterns of native and invasive species richness, and the effects of topography, climate, and roadside habitat disturbance on the invasive versus native plant species richness. We recorded 26 exotic invasive plant species that belong to 13 families and 21 genera, and 1,145 native plant species, belonging to 158 families and 628 genera. Along the Nujiang River valley, species richness of invasive plants decreased with increasing latitude and altitude, while species richness of native plants increased with increasing latitude, and showed a hump-shaped pattern with elevation. A generalized linear model was used to estimate the roles of roadside disturbance, climate, topography and soil nutrients on the distribution of both native and invasive species richness. Results of hierarchical variation partitioning revealed that roadside habitat disturbance had primary impact on the distribution of two groups of species. Pre·研究报告· 390 生 物 多 样 性 Biodiversity Science 第 24 卷 cipitation was the climatic determinant of invasive species diversity, and small-scale topographic factors, especially aspect, mainly affected native species diversity. It is likely that native species became drought-resistant in the evolutionary process while invasive species failed to adapt themselves to the local arid environments due to the short colonization time. This research supports the hypothesis that resource availability is the main factor limiting plant invasion, and highlights the negative effects of human activity on biodiversity. In addition, results of structural equation modelling revealed that native communities aren’t resistant to plant invasion. The negative relationship between invasive and native species richness reflects the different responses of the two group species to environmental factors.

Distinguishing Early Successional Plant Communities Using Ground-Level Hyperspectral Data

Abandoned agricultural fields have recently become more abundant in the U.S. and remain susceptible to species invasions after cultivation disturbance. As invasive species become more widespread with increases in anthropogenic activities, we need more effective ways to use limited resources for conservation of native ecosystems. Remote sensing can help us monitor the spread and effects of invasive species, and thus determine the species and locations to target for conservation. To examine this potential, we studied plant communities dominated by exotic invasive plant species in secondary successional fields in northern Virginia using ground-level hyperspectral data. Within these communities, ordination analyses of vegetation surveys revealed differences in species compositions among plots and fields. These differences among communities were also observed in the spectral data. Stepwise multiple linear regression analyses to determine which species influenced the ordination axes revealed that many of the influential species are considered invasive, again underscoring the influence of invasive species on community properties. Stepwise regression analyses also revealed that the most influential wavelengths for discrimination were distributed along the spectral profile from the visible to the near-infrared regions. A discriminant analysis using wavelengths selected with a principal components analysis demonstrated that different plant communities were separable using spectral data. These spectrally observable differences suggest that we can use hyperspectral data to distinguish among invasive-dominated successional plant communities in this region.