Journal articles: 'Exotic shrubs'

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Lucero, Jacob E., Taylor Noble, Stephanie Haas, Michael Westphal, H. Scott Butterfield, and Christopher J. Lortie. "The dark side of facilitation: native shrubs facilitate exotic annuals more strongly than native annuals." NeoBiota 44 (April 5, 2019): 75–93. http://dx.doi.org/10.3897/neobiota.44.33771.

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Positive interactions enhance biodiversity and ecosystem function, but can also exacerbate biological invasions. Facilitation of exotic invaders by exotic foundation species (invasional meltdown) has been studied extensively, but facilitation of exotic invaders by native foundation species has attracted less attention. Specifically, very few studies have examined the extent that native foundation species facilitate native and exotic competitors. Understanding the processes that mediate interactions between native and exotic species can help explain, predict, and improve management of biological invasions. Here, we examined the effects of native foundation shrubs on the relative abundance of the annual plant community – including native and exotic taxa – from 2015–2018 in a desert ecosystem at Carrizo Plain National Monument, California, USA (elevation: 723 m). Shrub effects varied by year and by the identity of annual species, but shrubs consistently enhanced the abundance of the annual plant community and facilitated both native (n=17 species) and exotic (n=4 species) taxa. However, at the provenance level, exotic annuals were facilitated 2.75 times stronger in abundance than native annuals, and exotic annuals were always more abundant than natives both near and away from shrubs. Our study reaffirms facilitation as an important process in the organisation of plant communities and confirms that both native and exotic species can form positive associations with native foundation species. However, facilitation by native foundation species can exacerbate biological invasions by increasing the local abundance of exotic invaders. Thus, the force of facilitation can have a dark side relevant to ecosystem function and management.

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Brockerhoff, E. G., and J. Bain. "Biosecurity implications of exotic beetles attacking trees and shrubs in New Zealand." New Zealand Plant Protection 53 (August 1, 2000): 321–27. http://dx.doi.org/10.30843/nzpp.2000.53.3623.

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A survey of exotic beetles that attack trees or shrubs in New Zealand found 51 species of mainly Australian (58) and European (25) origin In addition three biological control agents have been released against woody adventive plant pests The host range of most species is restricted to exotic crop and ornamental plants in New Zealand Nine polyphagous borers sometimes attack dead wood of indigenous species and at least one polyphagous root feeder may attack indigenous trees but the ecological impact of these species on indigenous forests appears negligible However some of the wood and bark borers as well as several defoliators are important pests of exotic crop and amenity plants Although this suggests that exotic phytophagous beetles pose a greater biosecurity threat to exotics than to indigenous species a greater surveillance effort in New Zealands indigenous forests appears necessary to detect potentially harmful invasions

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Bennett, Joseph R., Emily J. Young, David E. Giblin, Peter W. Dunwiddie, and Peter Arcese. "Avian dispersal of exotic shrubs in an archipelago." Écoscience 18, no. 4 (December 2011): 369–74. http://dx.doi.org/10.2980/18-4-3423.

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Madritch, Michael D., and Richard L. Lindroth. "Removal of invasive shrubs reduces exotic earthworm populations." Biological Invasions 11, no. 3 (May 13, 2008): 663–71. http://dx.doi.org/10.1007/s10530-008-9281-7.

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Edalgo, Jennifer A., Holly M. McChesney, Jason P. Love, and James T. Anderson. "Microhabitat use by white-footed mice Peromyscus leucopus in forested and old-field habitats occupied by Morrow’s honeysuckle Lonicera morrowii." Current Zoology 55, no. 2 (April 1, 2009): 111–22. http://dx.doi.org/10.1093/czoolo/55.2.111.

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Abstract We quantified microhabitat use by white-footed mice Peromyscus leucopus in forest and old-field habitats occupied by Morrow’s honeysuckle Lonicera morrowii, an invasive exotic shrub imported from Japan. Microhabitat characteristics were compared between trails used by mice (n = 124) and randomly selected trails (n = 127) in 4 study plots located at Fort Necessity National Battlefield, Farmington, Pennsylvania, USA. We compared 10 microhabitat variables between used and random trails using non-metric multidimensional scaling (NMDS) and classification and regression tree (CART) analysis. Trails used by mice were statistically different from randomly selected trails in both forested plots (P < 0.008) and old-field plots (P < 0.001). In the forested plots, trails of white-footed mice were more often associated with a greater percent cover (% cover) of coarse woody debris (CWD) than were randomly selected trails. In the old-field plots, mouse trails were commonly characterized by having a lower % cover of exotic herbaceous vegetation, a greater % cover of shrubs, and a greater % cover of Morrow’s honeysuckle than randomly selected trails. Our study indicates that white-footed mice do not move randomly and prefer areas of high structural complexity, thereby showing significant microhabitat preference. The preference of white-footed mice for areas with a relatively high percent cover of Morrow’s honeysuckle could 1) be a factor in the aggressive nature of the exotic honeysuckle shrub’s spread throughout the Battlefield or 2) cause the shrub to spread even faster into adjacent areas not yet occupied by Morrow’s honeysuckle.

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Silva, Taline Cristina da, Josilene Marinho da Silva, and Marcelo Alves Ramos. "What Factors Guide the Selection of Medicinal Plants in a Local Pharmacopoeia? A Case Study in a Rural Community from a Historically Transformed Atlantic Forest Landscape." Evidence-Based Complementary and Alternative Medicine 2018 (2018): 1–10. http://dx.doi.org/10.1155/2018/2519212.

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The criteria that local people use for selecting medicinal plants have been a recurrent topic in pharmacology and ethnobotany. Two of the current hypotheses regarding this phenomenon, ecological apparency and diversification, attempt to explain the inclusion of “apparent” and “non-apparent” and native and exotic taxa, respectively, in local pharmacopoeia. This study addresses the following questions: Do “apparent” and “non-apparent” medicinal plants have the same importance in local pharmacopoeia? Do “non-apparent” plants occupy more local categories of diseases than “apparent” plants? Do native and exotic medicinal plants have the same importance? Do exotic and native plants occupy different local categories of diseases? This study was conducted with householders of a community from Northeastern Brazil. Out of the 66 plant species cited, most were herbs (39 species), followed by trees and shrubs (27). Herbaceous species also occupied more local categories of diseases (51) than tree and shrub species (28). Furthermore, most of the species cited by the informants were exotic (42). Out of the 94 therapeutic applications cited in this research, 65 were treated with exotic species and 29 with native species, distributed among 13 body systems. These results support both the hypotheses of ecological apparency and diversification.

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Harrington, Robin A., Becky J. Brown, and Peter B. Reich. "Ecophysiology of exotic and native shrubs in Southern Wisconsin." Oecologia 80, no. 3 (1989): 356–67. http://dx.doi.org/10.1007/bf00379037.

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Harrington, Robin A., Becky J. Brown, Peter B. Reich, and James H. Fownes. "Ecophysiology of exotic and native shrubs in Southern Wisconsin." Oecologia 80, no. 3 (1989): 368–73. http://dx.doi.org/10.1007/bf00379038.

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Rodewald, Amanda D., Daniel P. Shustack, and Lauren E. Hitchcock. "Exotic shrubs as ephemeral ecological traps for nesting birds." Biological Invasions 12, no. 1 (January 30, 2009): 33–39. http://dx.doi.org/10.1007/s10530-009-9426-3.

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Kanegae, MF, G. Levy, and SR Freitas. "Habitat use by Collared Crescentchest (Melanopareia torquata) in a Cerrado in southeastern Brazil: implications for management." Brazilian Journal of Biology 72, no. 4 (November 2012): 865–71. http://dx.doi.org/10.1590/s1519-69842012000500013.

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The Collared Crescentchest (Melanopareia torquata) is a small insectivore endemic to the Cerrado. We examine the habitat use of this bird in a preserved Cerrado area in southeastern Brazil. Despite its occurrence in grassland with shrubs, the species used these areas less frequently than expected. The Collared Crescentchest mainly used areas of campo cerrado, but it was not recorded in a disturbed one. The common occurrence of exotic grass (U. decumbens) and cattle grazing may have brought about factors for its occurrence. However, the preference for native grasses may indicate an adverse indirect relationship against its occurence as there is competition between native and exotic grasses in the Cerrado. The presence of the Collared Crescentchest included the highest density of tall shrubs (>1 m) and native grasses. Conservation of the species should involve preserved areas of campo cerrado with a dominance of native grasses and tall shrubs.

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Chichizola, Giselle Ailin, Sofía Laura Gonzalez, and Adriana Edit Rovere. "Alien plant species on roadsides of the northwestern Patagonian steppe (Argentina)." PLOS ONE 16, no. 2 (February 11, 2021): e0246657. http://dx.doi.org/10.1371/journal.pone.0246657.

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The introduction of alien species represents one of the greatest threats to biodiversity worldwide. Highway construction increases the dispersal and invasion of exotic plant species. This study examined the assembly process of the plant communities to determine whether the roadsides of the Patagonian steppe represent a reservoir and dispersal source of invasive exotic species. We analyzed the composition of exotic and native species and functional groups present in the established vegetation and seed banks of roadsides and reference areas nearby. The type of dispersal of exotic and native species at the roadsides was also evaluated. Total cover and that of exotic and native species was lower at the roadsides than in the reference areas; however, at the roadsides the cover and seed abundance of exotic species was higher than that of native species. In the roadsides vegetation, native shrubs such as Acaena splendens predominated, along with exotic perennial herbs and grasses which were mainly represented by Rumex acetosella. In the seed bank the predominant species were exotic perennial herbs, also represented by R. acetosella, annual exotic species such as Epilobium brachycarpum and Verbascum thapsus, and annual native species such as Heliotropium paronychioides. No exotic shrubs were found either at the roadsides or in the reference areas. The species at the roadsides did not present a dominant type of dispersal. The abundance of exotic species at the roadsides, both in the aboveground vegetation and the seed bank, may be due to the stressful environment and the characteristics of the species themselves, such as the ability to form seed banks. This work revealed that the roadsides of the Patagonian steppe constitute reservoirs of invasive exotic species, highlighting the importance of identifying them and controlling their spread, with a view to generating ecosystem management programs.

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Kopij, Grzegorz. "Nesting Sites Of The Cape Sparrow Passer Melanurus In Maloti/Drakensber, Southern Africa." International Studies on Sparrows 37, no. 1 (December 1, 2013): 28–31. http://dx.doi.org/10.1515/isspar-2015-0022.

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Abstract In Maloti/Drakensberg region, southern Africa, Cape Sparrow locates nests (N=108) mainly in trees (38.9%), shrubs (27.8%) and man-made structures (29.6%). Most occupied trees were exotic (31.6%), while all (27.8%) occupied shrubs were indigenous. A few nests (3.8%) were found in disused weavers’ nests. Nesting sites ranged in height from 1.5 m to 10 m above the ground; on average – 4.2 m (N=52).

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Borgmann, Kathi L., and Amanda D. Rodewald. "NEST PREDATION IN AN URBANIZING LANDSCAPE:THE ROLE OF EXOTIC SHRUBS." Ecological Applications 14, no. 6 (December 2004): 1757–65. http://dx.doi.org/10.1890/03-5129.

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Applestein, Cara, Matthew J. Germino, and Matthew R. Fisk. "Vegetative Community Response to Landscape-Scale Post-fire Herbicide (Imazapic) Application." Invasive Plant Science and Management 11, no. 3 (September 2018): 127–35. http://dx.doi.org/10.1017/inp.2018.18.

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AbstractDisturbances such as wildfire create time-sensitive windows of opportunity for invasive plant treatment, and the timing of herbicide application relative to the time course of plant community development following fire can strongly influence herbicide effectiveness. We evaluated the effect of herbicide (imazapic) applied in the first winter or second fall after the 113,000 ha Soda wildfire on the target exotic annual grasses and also key non-target components of the plant community. We measured responses of exotic and native species cover, species diversity, and occurrence frequency of shrubs and forbs seeded before (1 to 2 or 9 to 10 mo) herbicide application. Additionally, we asked whether landscape factors, including topography, species richness, and/or soil characteristics, influenced the effectiveness of imazapic. Cover of exotic annual grass cover, but not of deep-rooted perennial bunchgrass, was less where imazapic had been applied, whereas more variability was evident in the response of Sandberg bluegrass (Poa secunda J. Presl) and seeded shrubs and forbs. Regression-tree analysis of the subset of plots measured both before and after the second fall application revealed greater reductions of exotic annual grass cover in places where their cover was <42% before spraying. Otherwise, imazapic effects did not vary with the landscape factors we analyzed.

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Noble, James C., David S. Hik, and Anthony R. E. Sinclair. "Landscape ecology of the burrowing bettong: fire and marsupial biocontrol of shrubs in semi-arid Australia." Rangeland Journal 29, no. 1 (2007): 107. http://dx.doi.org/10.1071/rj06041.

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Prior to European settlement, medium-sized marsupials, especially bettongs (Bettongia spp.), were widely distributed across arid and semi-arid Australia. Most disappeared rapidly in the late 1800s in the earliest settled rangelands such as the West Darling region of western New South Wales following the spread of domestic herbivores, rabbit invasion, exotic predators and loss of habitat. Because the burrowing bettong (Bettongia lesueur) is the only fossorial macropod species, it left a clearly visible record of its past presence, distribution and habitat preferences in the form of substantial relict warrens, particularly in stony, ‘hard-red’ habitats. With the reduction in fire frequency because of excessive grazing pressures following European settlement in the 19th century, there was a rapid increase in the density of unpalatable native shrubs. We examine the hypothesis that periodic wildfires and browsing by bettongs were together able to regulate shrub densities in semi-arid rangelands in Australia. Information from various sources concerning the effects of fire, rainfall and browsing on the demography of shrubs was used to construct a model of shrub population dynamics. The model indicates the potential for two states for a given bettong density: first, a low shrub density maintained by a combination of periodic fire and bettong browsing; and second, a high shrub density in the absence of fire. These results have broad implications for pastoral and conservation management in Australian semi-arid rangelands.

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Cleary, Daniel F. R., and Karl A. O. Eichhorn. "Variation in the composition and diversity of ground-layer herbs and shrubs in unburnt and burnt landscapes." Journal of Tropical Ecology 34, no. 4 (July 2018): 243–56. http://dx.doi.org/10.1017/s0266467418000196.

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Abstract:Forest fires pose an important threat to tropical rain-forest biodiversity. In the present study, we assessed ground layer (herb and shrub) communities in six differentially disturbed landscape plots in East Kalimantan, Indonesia, including primary and logged forest and once-, twice- and frequently-burnt forest. Overall, we recorded 175 species of herbs and shrubs; richness was highest in twice-burnt forest and lowest in logged forest. Vegetation and topographical variables including the percentage of the plot burnt and tree abundance were significant predictors of variation in composition. The main compositional gradient showed a clear distinction between subplots in unburnt versus burnt forest. A subset of subplots in burnt forest, however, clustered together with subplots from unburnt forest. These plots were located in a network of relatively unscathed forest along floodplains that persisted in the burnt-forest matrix. Small plant species associated with unburnt forest included several species of Dryopteridaceae, Marantaceae and Rubiaceae. Species associated with once- and twice-burnt forest included Mikania scandens (Compositae), Microlepia speluncae (Dennstaedtiaceae), Nephrolepis cf. biserrata (Nephrolepidaceae), Lygodium microphyllum (Schizaeaceae) and Hornstedtia cf. reticulata (Zingiberaceae). The frequently-burnt landscape plot was characterized by a high cover of the grass species Imperata cylindrica and the invasive exotic shrub Chromolaena odorata. Importantly, these species and other exotics had also invaded the once- and twice-burnt forest and represent a potential threat to forest recovery.

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Brudvig, Lars A., and Christopher W. Evans. "Competitive Effects of Native and Exotic Shrubs on Quercus alba Seedlings." Northeastern Naturalist 13, no. 2 (June 2006): 259–68. http://dx.doi.org/10.1656/1092-6194(2006)13[259:ceonae]2.0.co;2.

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KISSEL, RUTH M., J. BASTOW WILSON, PETER BANNISTER, and ALAN F. MARK. "WATER RELATIONS OF SOME NATIVE AND EXOTIC SHRUBS OF NEW ZEALAND." New Phytologist 107, no. 1 (September 1987): 29–37. http://dx.doi.org/10.1111/j.1469-8137.1987.tb04879.x.

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Miranda, María, Marisa Sicilia, Jordi Bartolomé, Eduarda Molina-Alcaide, Lucía Gálvez-Bravo, and Jorge Cassinello. "Contrasting feeding patterns of native red deer and two exotic ungulates in a Mediterranean ecosystem." Wildlife Research 39, no. 2 (2012): 171. http://dx.doi.org/10.1071/wr11146.

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Context Ungulates have been widely introduced in multiple ecosystems throughout the world due to their value as food and for sport hunting. The identification of foraging preferences of exotic and native ungulates living in sympatry is, therefore, becoming increasingly important in order to assess potential impacts of introduced animals on the host ecosystem. Aims To describe species-specific foraging strategies and infer resource selection overlap between native and exotic ungulates. Methods We compared the trophic ecology of three sympatric ungulate species living in a Mediterranean landscape: the native Iberian red deer Cervus elaphus hispanicus, and two exotic bovids, the European mouflon Ovis orientalis musimon and the aoudad Ammotragus lervia. We simultaneously determined herbivore diet through analyses of botanical content in faeces and assessed the nutritional content of these diets. Key results Higher selection of shrubs by deer was sustained throughout the year, while bovids showed seasonal shifts in forage selection. Both bovids displayed a selective dietary strategy directed towards a higher overall nutritional quality than that of deer. Divergent exploitation patterns between the studied cervid and bovids might be related to body mass and physiological adaptations to overcome secondary defence compounds of shrubs, and were largely affected by seasonal changes in the nutritional value of available vegetation. Ecological theory suggests that diet overlap should be greater between similar-sized species. Indeed, both exotics showed similar, sometimes overlapping, dietary patterns that could lead to potential competition in the use of resources. Native red deer preferences only showed some overlap with those of exotic mouflon under constrained summer conditions. Conclusions Dietary overlap between deer and mouflon and between aoudad and mouflon during limiting summer conditions could entail a potential competitive interaction under more even densities of the study species, since a concurrent habitat overlap between those pairs of species has previously been reported. Implications The outcomes of our study suggest the need for an integration of habitat and ungulate management. Management actions in Mediterranean rangelands should be directed towards protecting habitat conditions so that biodiversity is enhanced along with the presence of sustainable communities of large herbivores. Management directed towards ungulates should maintain moderate stocking rates and monitor and control introduced and native populations.

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Crombie, M. D., R. R. Germain, and P. Arcese. "Nest-site preference and reproductive performance of Song Sparrows (Melospiza melodia) in historically extant and colonist shrub species." Canadian Journal of Zoology 95, no. 2 (February 2017): 115–21. http://dx.doi.org/10.1139/cjz-2016-0189.

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Many studies report mixed results on the influence of invasive plants on native animals, partly due to uncertainties about habitat preference and reproductive performance in native animals before and after plant invasion. We used vegetation surveys 20 years apart and 18 years of breeding data from Song Sparrows (Melospiza melodia (A. Wilson, 1810)) to compare nest-site preference and reproductive performance during the colonization of Mandarte Island, British Columbia, by one shrub species native to the region but historically absent from the island (red elderberry, Sambucus racemosa L.) and another species that is exotic to North America (Himalayan blackberry, Rubus armeniacus Focke = Rubus bifrons Vest). Nest-site preference declined where red elderberry increased but was unrelated to change in the cover of Himalayan blackberry. Song Sparrows nested in trailing blackberry (Rubus ursinus Cham. and Schltdl.) and its exotic congener Himalayan blackberry in preference to two common shrubs native to Mandarte Island (Nootka rose, Rosa nutkana C. Presl; snowberry, Symphoricarpos albus (L.) S.F. Blake) and built just 1 of 1051 nests in red elderberry. In contrast, reproductive performance was similar in all shrub species used regularly as nest substrates. Our results show that Song Sparrow nest-site preference and reproductive performance were independent of plant species origin.

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Рунова, E. Runova, Гнаткович, and Pavel Gnatkovich. "Prospects for the introduction of exotic species in the range of private gardens, green spaces of Bratsk." Forestry Engineering Journal 4, no. 2 (June 10, 2014): 68–78. http://dx.doi.org/10.12737/4509.

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The possibility of expanding the range of urban green space through the use of exotic species of wood is considered. Due to the lack of specialized institutions dealing with introductory test, it is proposed to use the experience of the introduction of trees and shrubs of private gardens for their subsequent use in green building of Bratsk. Phytopathologic and sanitary evaluation of plantations of private gardens is held, average morphometric parameters, age, life forms and eco-geographical groups of exotic species are defined. Integral evaluation successful introduction was conducted and classes of promising studied plants are defined.

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Borgmann, Kathi L., and Amanda D. Rodewald. "Forest Restoration in Urbanizing Landscapes: Interactions Between Land Uses and Exotic Shrubs." Restoration Ecology 13, no. 2 (June 2005): 334–40. http://dx.doi.org/10.1111/j.1526-100x.2005.00042.x.

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Smith, J. M. B. "Exotic trees and shrubs along a roadside transect between Sydney and Brisbane." Australian Geographer 16, no. 4 (November 1985): 264–71. http://dx.doi.org/10.1080/00049188508702882.

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Shustack, Daniel P., Amanda D. Rodewald, and Thomas A. Waite. "Springtime in the city: exotic shrubs promote earlier greenup in urban forests." Biological Invasions 11, no. 6 (September 12, 2008): 1357–71. http://dx.doi.org/10.1007/s10530-008-9343-x.

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Szwajkowska-Michałek, Lidia, Anna Przybylska-Balcerek, Tomasz Rogoziński, and Kinga Stuper-Szablewska. "Phenolic Compounds in Trees and Shrubs of Central Europe." Applied Sciences 10, no. 19 (October 2, 2020): 6907. http://dx.doi.org/10.3390/app10196907.

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Plants produce specific structures constituting barriers, hindering the penetration of pathogens, while they also produce substances inhibiting pathogen growth. These compounds are secondary metabolites, such as phenolics, terpenoids, sesquiterpenoids, resins, tannins and alkaloids. Bioactive compounds are secondary metabolites from trees and shrubs and are used in medicine, herbal medicine and cosmetology. To date, fruits and flowers of exotic trees and shrubs have been primarily used as sources of bioactive compounds. In turn, the search for new sources of bioactive compounds is currently focused on native plant species due to their availability. The application of such raw materials needs to be based on knowledge of their chemical composition, particularly health-promoting or therapeutic compounds. Research conducted to date on European trees and shrubs has been scarce. This paper presents the results of literature studies conducted to systematise the knowledge on phenolic compounds found in trees and shrubs native to central Europe. The aim of this review is to provide available information on the subject and to indicate gaps in the present knowledge.

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ROOTHAERT, R., S. FRANZEL, and M. KIURA. "ON-FARM EVALUATION OF FODDER TREES AND SHRUBS PREFERRED BY FARMERS IN CENTRAL KENYA." Experimental Agriculture 39, no. 4 (September 29, 2003): 423–40. http://dx.doi.org/10.1017/s0014479703001376.

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The small amount of on-farm research that has been carried out with fodder trees in Africa has mainly involved exotic species selected by researchers rather than farmers. In this study, farmers who had participated in a pre-planting survey chose, during feedback meetings, seedlings of indigenous, naturalized and some exotic fodder trees from a nursery. They planted them on-farm, where the planting niches, management, biomass production, and animal response were evaluated over a short period, and compared with the results of the earlier survey. The farmers came from three agro-ecological zones in central Kenya with respective mean annual rainfall totals of 775, 950 and 1300 mm. Data were collected at two months, one year and two years after planting. The feedback meetings proved important to the understanding of discrepancies between the earlier survey results and farmers' practices. Survival and growth of seedlings, manure application by farmers, and percentage of trees pruned for fodder, differed among species. The farmers showed a strong interest in experimenting with and actively cultivating local fodder trees.

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Bravo, Melissa, Antonio DiTommaso, and David Hayes. "Exotic Plant Inventory, Landscape Survey, and Invasiveness Assessment: Roosevelt-Vanderbilt National Historic Sites, Hyde Park, NY." HortTechnology 22, no. 5 (October 2012): 682–93. http://dx.doi.org/10.21273/horttech.22.5.682.

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An exotic plant cultural landscape inventory, area wide survey, and natural resource area invasiveness assessment was conducted in 2002 at the Roosevelt-Vanderbilt (ROVA) National Historic Sites (NHS) in Hyde Park, NY. At the species level, 40% of 90 assessed landscape species had not escaped cultivation, 44% had escaped and invaded natural resource areas, and 16% were categorized as migratory invaders. The most prolific introduced woody trees and vines at ROVA are members of the trumpetvine, bittersweet, pea, buckthorn, quassia, and grape families (Bignoniaceae, Celastraceae, Fabaceae, Rhamnaceae, Simaroubaceae, and Vitaceae, respectively). Shrub species occurring with more frequency in the natural areas than other escapes are the introduced native atlantic nine bark (Physocarpus opulifolius), burning bush (Euonymus alatus), forsythia (Forsythia sp.), japanese barberry (Berberis thunbergii), morrow’s honeysuckle (Lonicera morrowii), tatarian honeysuckle (Lonicera tatarica), and mock orange (Philadelphus sp.). For the subset of assessed woody vines, shrubs, and tree species found in cultivation for at least 50 to 67 years (the “50 plus club species”), slightly more had escaped from cultivation for the Vanderbilt Mansion (VAMA) and Eleanor Roosevelt (ELRO) estates but for the Franklin Delano Roosevelt (FDR) collection the numbers were equivalent. The approach used in this study illustrates with data the “movement” of exotics over a significant period of time and underscores the importance of site-specific and species-specific assessments. This assessment also emphasizes the value of understanding the history (e.g., cultivated, cultivated escaped, or migratory invaders), purpose (e.g., aquatic, crop garden forb, groundcover, ornamental, or weed), and management over time (e.g., long since abandoned, recently abandoned, or still maintained, etc.) of the geographic area under consideration and the use of available exotic invasive plant lists to conduct such assessments.

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Muñoz-Barcia, C. V., L. Lagos, C. A. Blanco-Arias, R. Díaz-Varela, and J. Fagúndez. "Habitat quality assessment of Atlantic wet heathlands in Serra do Xistral, NW Spain." Cuadernos de Investigación Geográfica 45, no. 2 (September 4, 2019): 533. http://dx.doi.org/10.18172/cig.3628.

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The assessment of habitat quality, especially in semi-natural managed systems, provides a powerful tool for monitoring short and long-term conservation actions. The Erica mackayana Atlantic wet heathlands of the Serra do Xistral protected area in Galicia, NW Spain, represent a dynamic system with high conservation value associated to traditional management through grazing of free-ranging cattle and wild ponies. Here, we aimed to develop a spatially-explicit, quantitative method for Habitat Quality Assessment, defining an optimum state and the alternative states that may arise from habitat degradation. Vegetation structure, grass-shrub cover ratio, gorse cover, presence of bracken, exotic species such as pine trees and saplings, erosive events and altered hydrological dynamics were identified as the main indicators of habitat degradation. A heterogeneous vegetation structure with a dominant shrub cover of c.0.5 m height and constant gaps among shrubs, with a limited cover of gorse and absence of pine trees, bramble and bracken, and absence of erosive events was recognized as the optimum state. We applied the Habitat Quality Assessment (HQA) method to a pilot area within the Xistral protected site. Wet heathland was the dominant habitat, covering 37.1% of the area. 7.0% of the assessed heathlands were recognized as in the optimum state for habitat quality. Recommendations are made for habitat management to revert low scores, mainly by the adjustment of livestock numbers and the removal of exotic pine trees.

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Wyse, Sarah V., George L. W. Perry, Dean M. O’Connell, Phillip S. Holland, Monique J. Wright, Catherine L. Hosted, Samuel L. Whitelock, Ian J. Geary, Kévin J. L. Maurin, and Timothy J. Curran. "A quantitative assessment of shoot flammability for 60 tree and shrub species supports rankings based on expert opinion." International Journal of Wildland Fire 25, no. 4 (2016): 466. http://dx.doi.org/10.1071/wf15047.

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Fire is an important ecological disturbance in vegetated ecosystems across the globe, and also has considerable impacts on human infrastructure. Vegetation flammability is a key bottom-up control on fire regimes and on the nature of individual fires. Although New Zealand (NZ) historically had low fire frequencies, anthropogenic fires have considerably impacted indigenous vegetation as humans used fire extensively to clear forests. Few studies of vegetation flammability have been undertaken in NZ and only one has compared the flammability of indigenous plants; this was a qualitative assessment derived from expert opinion. We addressed this knowledge gap by measuring the flammability of terminal shoots from a range of trees and shrubs found in NZ. We quantified shoot flammability of 60 indigenous and exotic species, and compared our experimentally derived ranking with expert opinion. The most flammable species was the invasive exotic shrub Gorse (Ulex europaeus), followed by Manna Gum (Eucalyptus viminalis), Kūmarahou (Pomaderris kumeraho), Rimu (Dacrydium cupressinum) and Silver Beech (Lophozonia menziesii). Our experimentally derived ranking was strongly correlated with expert opinion, lending support to both methods. Our results are useful to ecologists seeking to understand how fires have and will influence NZ’s ecosystems, and for fire managers identifying high-risk landscapes, and low flammability species for ‘green firebreaks’.

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Frank, Graham, Michael Saunders, and Michael Jenkins. "Short-Term Vegetation Responses to Invasive Shrub Control Techniques for Amur Honeysuckle (Lonicera maackii [Rupr.] Herder)." Forests 9, no. 10 (September 30, 2018): 607. http://dx.doi.org/10.3390/f9100607.

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Invasive shrubs in forest understories threaten biodiversity and forest regeneration in the eastern United States. Controlling these extensive monotypic shrub thickets is a protracted process that slows the restoration of degraded forest land. Invasive shrub removal can be accelerated by using forestry mulching heads, but evidence from the western United States indicates that mulching heads can promote exotic species establishment and mulch deposition can reduce native plant species abundance. We compared the effectiveness of the mulching head and the “cut-stump” method for controlling the invasive shrub Amur honeysuckle (Lonicera maackii), as well as their impacts on native plant community recovery, in mixed-hardwood forests of Indiana. After two growing seasons, mulching head treatment resulted in greater L. maackii regrowth and regeneration. The recovery of native plant abundance and diversity following shrub removal did not differ between the two methods. However, mulch deposition was associated with increased abundance of garlic mustard (Alliaria petiolata), an invasive forb. Increasing mulching head treatment depth reduced L. maackii regrowth, but additional study is needed to determine how it affects plant community responses. The mulching head is a promising technique for invasive shrub control and investigating tradeoffs between reducing landscape-scale propagule pressure and increased local establishment will further inform its utility.

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Collette, Liana K. D., and Jason Pither. "Insect assemblages associated with the exotic riparian shrub Russian olive (Elaeagnaceae), and co-occurring native shrubs in British Columbia, Canada." Canadian Entomologist 148, no. 3 (December 7, 2015): 316–28. http://dx.doi.org/10.4039/tce.2015.63.

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AbstractRussian olive (Elaeagnus angustifolia Linnaeus; Elaeagnaceae) is an exotic shrub/tree that has become invasive in many riparian ecosystems throughout semi-arid, western North America, including southern British Columbia, Canada. Despite its prevalence and the potentially dramatic impacts it can have on riparian and aquatic ecosystems, little is known about the insect communities associated with Russian olive within its invaded range. At six sites throughout the Okanagan valley of southern British Columbia, Canada, we compared the diversity of insects associated with Russian olive plants to that of insects associated with two commonly co-occurring native plant species: Woods’ rose (Rosa woodsii Lindley; Rosaceae) and Saskatoon (Amelanchier alnifolia (Nuttall) Nuttall ex Roemer; Rosaceae). Total abundance did not differ significantly among plant types. Family richness and Shannon diversity differed significantly between Woods’ rose and Saskatoon, but not between either of these plant types and Russian olive. An abundance of Thripidae (Thysanoptera) on Russian olive and Tingidae (Hemiptera) on Saskatoon contributed to significant compositional differences among plant types. The families Chloropidae (Diptera), Heleomyzidae (Diptera), and Gryllidae (Orthoptera) were uniquely associated with Russian olive, albeit in low abundances. Our study provides valuable and novel information about the diversity of insects associated with an emerging plant invader of western Canada.

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Scheiber, S. M., E. F. Gilman, D. R. Sandrock, M. Paz, C. Wiese, and Meghan M. Brennan. "Postestablishment Landscape Performance of Florida Native and Exotic Shrubs Under Irrigated and Nonirrigated Conditions." HortTechnology 18, no. 1 (January 2008): 59–67. http://dx.doi.org/10.21273/horttech.18.1.59.

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Although new and innovative measures to reduce landscape water consumption are being sought, traditional methods of water restrictions and plant selection prevail. Species native to North America are often promoted as drought tolerant with little information to support or refute such claims. Furthermore, species performance is unknown in maintained environments such as commercial and residential landscapes. Thus, 10 native and 10 exotic species, commonly used in landscapes, were evaluated independently for postestablishment growth and aesthetics under irrigated and nonirrigated landscape conditions. Growth indices were recorded monthly, with dieback and plant density evaluated at termination of the experiment. At termination of the experiment, canopy size of eight native [beautyberry (Callicarpa americana), fringe tree (Chionanthus virginicus), yaupon holly (Ilex vomitoria ‘Nana’), virginia sweetspire (Itea virginica), wax myrtle (Myrica cerifera), chickasaw plum (Prunus angustifolia), saw palmetto (Serenoa repens), and coontie (Zamia floridana)] and eight exotic [golden dewdrop (Duranta erecta), cape jasmine (Gardenia augusta), crape myrtle (Lagerstroemia indica), oleander (Nerium oleander), japanese pittosporum (Pittosporum tobira), indian hawthorn (Rhaphiolepis indica), sweet viburnum (Viburnum odoratissimum), and sandankwa viburnum (V. suspensum)] species were similar for irrigated and nonirrigated treatments. Irrigation resulted in larger canopy sizes for two native [walter's viburnum (V. obovatum) and inkberry (I. glabra)] and two nonnative [japanese privet (Ligustrum japonicum) and fringe flower (Loropetalum chinensis)] species. Among the native species with larger canopy sizes under irrigated conditions, all are indigenous to swamps and streams. With the exception of virginia sweetspire, plant density and dieback were similar for irrigated and nonirrigated plants of all taxa examined. Irrigated virginia sweetspire plants had higher plant density and dieback ratings than nonirrigated plants. Results indicate that, aesthetically, irrigated and nonirrigated plants were similar. Data emphasize the importance of selecting plant material adapted to existing environmental landscape conditions.

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Fascella, G., M. M. Mammano, M. Airò, G. Giardina, and M. Lambardi. "Micropropagation of Mediterranean and exotic shrubs: protocols for endangered and high-value plant species." Acta Horticulturae, no. 1285 (July 2020): 51–56. http://dx.doi.org/10.17660/actahortic.2020.1285.8.

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Shiflett, Sheri A., Julie C. Zinnert, and Donald R. Young. "Functional traits of expanding, thicket-forming shrubs: contrasting strategies between exotic and native species." Ecosphere 8, no. 9 (September 2017): e01918. http://dx.doi.org/10.1002/ecs2.1918.

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Reynolds, Lindsay V., and David J. Cooper. "Ecosystem response to removal of exotic riparian shrubs and a transition to upland vegetation." Plant Ecology 212, no. 8 (February 17, 2011): 1243–61. http://dx.doi.org/10.1007/s11258-011-9901-7.

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Horton, David R., Eugene Miliczky, Timothy D. Waters, Daniel Burckhardt, and Susan E. Halbert. "Exotic Psyllids and Exotic Hosts: Accumulation of Nonnative Psylloidea in North America (Hemiptera)." Annals of the Entomological Society of America 114, no. 4 (April 28, 2021): 425–47. http://dx.doi.org/10.1093/aesa/saab014.

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Abstract The Psylloidea (Hemiptera) comprise ~4,000 species of small sap-feeding insects known as psyllids or jumping plant-lice. We summarize species composition of the nonnative psyllid fauna in North America and review detection records, current distributions, host use, life histories, and geographical sources. Forty-six species are considered to be nonnative accounting for ~10% of the known North American psyllid fauna. The family Psyllidae is overrepresented in the pool of exotics (52% of exotic species) relative to global psyllid diversity, whereas Triozidae (at 11% of exotic species) is underrepresented. Records of initial detection range from the 1832 detection of a European pear psyllid to the 2016 detection of a Ficus specialist from Asia. Many species exhibit discontinuous distributions in North America presumably caused by multiple introductions or by secondary spread of established populations. Host plants of nonnative species are almost exclusively trees and shrubs. The factor most correlated with introduction is presence of hosts from the psyllid’s native region. Virtually all host plants in North America have been imported intentionally for human-related use, with initial importation beginning in the 1500s and 1600s. Arrival of host plants in North America often preceded psyllid detection or arrival by decades or centuries. There has been almost no spillover by psyllids onto native plant species reflecting the narrow host range of Psylloidea. A glaring exception is the recent damaging colonization of a native Fraxinus closely related to the psyllid’s European Fraxinus host. Biological and geographical traits correlated with arrival and establishment of nonnative psyllids have shifted through time. Temperate Europe was the source of the earliest arriving species, with initial detection records primarily in New England and eastern Canada. In contrast, recent arrivals are mostly Myrtaceae- and Fabaceae-feeding species from the Neotropics or Australia, with detection records limited mostly to Florida or California. Early-arriving, temperate zone species exhibit a formal winter diapause while recent arrivals from the Neotropics and Australia appear to reproduce more-or-less continuously.

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Gtari, Maher, and Jeffrey O. Dawson. "An overview of actinorhizal plants in Africa." Functional Plant Biology 38, no. 9 (2011): 653. http://dx.doi.org/10.1071/fp11009.

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A compilation and synthesis of information derived from plant databases and other sources on the occurrence, diversity and geographic distribution of actinorhizal plants in Africa is presented in this review. Actinorhizal plants are a specific group of non-leguminous, woody dicots having symbiotic, nitrogen-fixing root nodules that are induced on roots of actinorhizal plant species by soil actinomycetes of the genus Frankia. There is a lack of basic information on actinorhizal plants in Africa compared with other major land masses in the world. Results indicate that most, if not all, African countries and climatic regions have native or introduced actinorhizal species. A synthesis of available information indicates that there are six families, nine genera and 38 reported species of actinorhizal plants in Africa. Of these, 21 species are native and 17 are exotic. The families and corresponding number of species in each genus are: Betulaceae (native Alnus glutinosa (1), exotic Alnus (2)); Casuarinaceae (exotic Casuarina (5), exotic Allocasuarina (3), exotic Gymnostoma deplancheana (1)); Coriariaceae (native Coriaria myrtifolia (1)); Myricaceae (native Morella (19), exotic Morella cerifera (1)); Rhamnaceae (exotic Ceanothus caeruleus (1), exotic Colletia paradoxa (1)); and Elaeagnaceae (exotic Eleaegnus angustifolia (1)). Four reports of native, actinorhizal Ceanothus species in Africa found in the database were determined to be false, instead, being non-actinorhizal species. Widespread plantings of exotic Casuarinaceae have been introduced into tropical and arid zones of Africa as multipurpose trees, especially in arid regions where native species do not occur. There is a diverse assemblage of native species of Morella in Africa, mostly shrubs or small trees, which provide medicine, other useful chemicals and wildlife habitat. Many native Morella species are isolated in montane islands, apparently leading to greater speciation than in Eurasia from where the genus migrated into Africa. The current status and knowledge of African actinorhizal plants indicates a need to focus research on their biogeography, biology, ecology, genetics and use.

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Mexi, Alexandru. "Planting patterns and exotic plants in nineteenth-century Bucharest public gardens." Gardens and Landscapes of Portugal 6, no. 1 (September 1, 2019): 37–47. http://dx.doi.org/10.2478/glp-2019-0011.

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Abstract The first two public gardens in Bucharest, as well as some of the oldest in the South and East regions of nowadays country of Romania, were designed, built and planted around the mid-nineteenth century by a German-born landscape gardener named Carl Friedrich Wilhelm Meyer. These two public gardens were designed according to modern nineteenth century landscaping concepts and were planted with exotic species of flowers, shrubs and trees not common at that time either in Bucharest or anywhere in the Romanian provinces south or east of the Carpathians. To better understand the design, development, and meaning of these gardens, this paper aims to analyze the specific palette of ornamental species of plants and the planting patterns that were used for the Kiseleff and Cișmigiu gardens in Bucharest and to outline the importance of their use.

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C. Horvitz, Carol, Anthony L. Koop, and Kelley D. Erickson. "Time-invariant and stochastic disperser-structured matrix models: Invasion rates of fleshy-fruited exotic shrubs." Discrete & Continuous Dynamical Systems - B 20, no. 6 (2015): 1639–62. http://dx.doi.org/10.3934/dcdsb.2015.20.1639.

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Vergara-Tabares, David L., Martín Toledo, Emiliano García, and Susana I. Peluc. "Aliens will provide: avian responses to a new temporal resource offered by ornithocorous exotic shrubs." Oecologia 188, no. 1 (June 26, 2018): 173–82. http://dx.doi.org/10.1007/s00442-018-4207-2.

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Nield, Andrew P., Philip G. Ladd, and Colin J. Yates. "Reproductive biology, post-fire succession dynamics and population viability analysis of the critically endangered Western Australian shrub Calytrix breviseta subsp. breviseta (Myrtaceae)." Australian Journal of Botany 57, no. 6 (2009): 451. http://dx.doi.org/10.1071/bt09043.

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Calytrix breviseta Lindl. subsp. breviseta is a critically endangered, obligate-seeder shrub within fire-prone kwongan of south-west Western Australia. Little is known about the species’ reproductive biology and how threatening processes, particularly altered fire regimes and exotic species invasion, will impact the long-term viability of the species. This study aims to elucidate the species’ reproductive biology and patterns of seedling recruitment during succession after fire. The effects of changes to the fire return interval and exotic species invasion on the long-term viability of the species is also described. The species exhibits abundant recruitment following fire and the application of a smoke treatment significantly improves germination, similar to many other Western Australian shrubs. However, significant inter-fire recruitment was observed up to 10 years following fire, leading to the presence of multi-aged subpopulations, although seedling recruitment was negligible >20 years after fire. The juvenile period is short at 3–4 years to first flowering. Population viability analysis (PVA) predicted that the optimal fire return interval to maintain C. breviseta subsp. breviseta was dependent on the carrying capacity (K) of the community and the number of individuals present. Carrying capacity will be related to site quality and competition from invasive species. PVA showed that if K remains high, then the optimal fire return interval is ~15–20 years, but under lower carrying capacity, (i.e. weed competition) fires decrease the likelihood of population survival.

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Davies, Kirk W., and Jon D. Bates. "Re-introducing fire in sagebrush steppe experiencing decreased fire frequency: does burning promote spatial and temporal heterogeneity?" International Journal of Wildland Fire 29, no. 8 (2020): 686. http://dx.doi.org/10.1071/wf20018.

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Fire frequency has decreased in many shrub-steppe communities. Re-introducing fire may be needed to increase spatial and temporal variability in vegetation, but is often hindered by concerns of undesired vegetation shifts. These concerns arise, in part, because long-term effects of fire re-introduction in these communities after prolonged fire exclusion and other departures from historical conditions are unknown. To better understand the effects of re-introducing fire, we evaluated plant community response to re-introducing fire for 12 years post fire in six mountain big sagebrush communities. Herbaceous biomass production was 1.7-fold greater in burned compared with unburned areas at the conclusion of the study. Exotic annual grasses appeared to be problematic in the first 8 years post fire, but became inconsequential (~1% cover) by the end of the study. Re-introducing fire promoted other shrubs (excluding sagebrush) that were probably inhibited by competition from sagebrush. Sagebrush cover and density remained low in burned areas for the duration of the study, because of limited recruitment in the years immediately post fire and competition from herbaceous vegetation. Re-introducing fire appears to increase temporal and spatial heterogeneity in shrub-steppe communities experiencing prolonged fire exclusion and, therefore, may be needed to maintain a diversity of plant communities.

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Kleinhesselink, Andrew R., Susan M. Magnoli, and J. Hall Cushman. "Shrubs as ecosystem engineers across an environmental gradient: effects on species richness and exotic plant invasion." Oecologia 175, no. 4 (May 29, 2014): 1277–90. http://dx.doi.org/10.1007/s00442-014-2972-0.

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Domic, Alejandra, José Capriles, Katerine Escobar-Torrez, Calogero Santoro, and Antonio Maldonado. "Two Thousand Years of Land-Use and Vegetation Evolution in the Andean Highlands of Northern Chile Inferred from Pollen and Charcoal Analyses." Quaternary 1, no. 3 (December 19, 2018): 32. http://dx.doi.org/10.3390/quat1030032.

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The European conquest of the New World produced major socio-environmental reorganization in the Americas, but for many specific regions and ecosystems, we still do not understand how these changes occurred within a broader temporal framework. In this paper, we reconstruct the long-term environmental and vegetation changes experienced by high-altitude wetlands of the southcentral Andes over the last two millennia. Pollen and charcoal analyses of a 5.5-m-long core recovered from the semi-arid puna of northern Chile indicate that while climatic drivers influenced vegetation turnaround, human land use and management strategies significantly affected long-term changes. Our results indicate that the puna vegetation mostly dominated by grasslands and some peatland taxa stabilized during the late Holocene, xerophytic shrubs expanded during extremely dry events, and peatland vegetation persisted in relation to landscape-scale management strategies by Andean pastoralist societies. Environmental changes produced during the post-conquest period included the introduction of exotic taxa, such as clovers, associated with the translocation of exotic herding animals (sheep, cattle, and donkeys) and a deterioration in the management of highland wetlands.

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Lei, Yuan, Zhao-lu Wu, Liang-zao Wu, Hui-ling Shi, Hao-tian Bai, Wei Fu, and Yuan Ye. "Interspecific correlation between exotic and native plants under artificial wetland forests on the Dianchi lakeside, south-west China." Marine and Freshwater Research 69, no. 5 (2018): 669. http://dx.doi.org/10.1071/mf17177.

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The core issue of community ecology and biodiversity is the coexistence of species in a real community, but few studies have considered species coexistence in artificial wetland forests. The present study focused on interspecific correlations of exotic and native species in 8-year-old artificial wetland forests. Four large plots (each 1500m2) were established to record the species and abundance of all plants; 160 quadrats (1×1m) were set to record the number, height and coverage of each plant species. In the large plots, 78 species (6 trees, 11 shrubs and 61 herbs) were recorded. The interspecific relationships of major species (frequency >3%) from quadrats were analysed using the Chi-Square test and Spearman rank correlation coefficient index. Of 253 species pairs, 49 and 45 were significant (P<0.05), with positive and negative correlations respectively, showing intense interspecific competition. Ward’s method of hierarchical clustering was used to divide the major species from quadrats into three and five ecological species groups at a rescaled distance cluster combine of 20 and 10 respectively. Dominant invasive species (Solidago canadensis, Ageratina adenophora and Bidens pilosa) formed monodominant patches; however, species of different sizes and ecological demands, whether exotic or native, could coexist. These findings imply that exotic species can coexist with native species and become a common species composition when they have existed for a sufficient period time in artificial wetland forests.

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Prasad, Ayesha E. "Landscape-scale relationships between the exotic invasive shrub Lantana camara and native plants in a tropical deciduous forest in southern India." Journal of Tropical Ecology 28, no. 1 (December 8, 2011): 55–64. http://dx.doi.org/10.1017/s0266467411000563.

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Abstract:Understanding exotic–native plant relationships within the context of landscape-scale environmental factors such as rainfall, topography, disturbance and forest structure, is important for distinguishing the role of invasions in native plant community change. In this study, the relationship between Lantana camara invasion and native forest understorey vegetation was described after accounting for environmental influences. Rainfall, terrain slope, altitude and fire frequency were measured from GIS layers, and tree density, dry above-ground L. camara biomass, and native plant abundance and species richness were measured in nested plots (four 1 × 1-m plots for grass, tree seedlings and L. camara within one 5-m-radius plot for tree saplings and herbs and shrubs within one 10-m-radius plot for trees) at 80 locations distributed across Bandipur Tiger Reserve, a tropical deciduous forest in southern India. Relationships between environmental factors and L. camara abundance were described using a multiple regression. Further, the role of L. camara abundance in explaining residual variation in native vegetation, after accounting for environmental influences, was described using linear models. Lantana camara abundance decreased with increasing tree density, supporting the notion that it thrives in disturbed forest with fewer trees. Whereas native tree seedling and herb and shrub density showed no relationship to L. camara abundance, both tree sapling density and grass volume decreased under L. camara biomass exceeding 2 kg m−2. These data suggest that, by association with grass decline and decreased recruitment of tree saplings, L. camara may be linked to the gradual transition of these tropical deciduous forests into exotic-dominated shrubland, and overall native biodiversity loss.

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Noumi, Zouhaier. "Effects of exotic and endogenous shrubs on understory vegetation and soil nutrients in the south of Tunisia." Journal of Arid Land 7, no. 4 (April 6, 2015): 481–87. http://dx.doi.org/10.1007/s40333-015-0047-7.

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McWilliams, Edward L. "669 The Impact of Gulf Coast Hurricanes on Pecans, Ornamental Trees, and Invasive Exotic Species." HortScience 34, no. 3 (June 1999): 563D—563. http://dx.doi.org/10.21273/hortsci.34.3.563d.

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Hurricanes strike the Gulf Coast of the United States every few years. We briefly describe generalized hurricane tracks for the Gulf Coast and vegetation damage using NDVI satellite imagery as well as slides of damaged urban trees in Florida. The impact of recent hurricanes on both pecan defoliation and production and on initial damage and subsequent recovery of various ornamental trees is described. Pecan harvests were greatly reduced by hurricanes that struck late in the season in both Alabama and Texas. Varieties of pecans varied in their susceptibility to various stresses. Pine forests were sometimes devastated by certain hurricanes while live oaks, various shrubs, and important insects often survived the same storms with little damage. Many exotic ornamental plants including Chinese tallow are either adventive or invasive along the Gulf Coast. Species escape from cultivation over a long period of time and exhibit different invasion lag phases. In Texas and Louisiana, hurricane damage to native trees allowed Chinese tallow seedlings and saplings to subsequently dominate some areas as a result of the disturbance. One delayed ecological response to hurricanes and typhoons is an acceleration of ongoing exotic plant invasions.

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M. Date, E., H. F. Recher, H. A. Ford, and D. A. Stewart. "The conservation and ecology of rainforest pigeons in northeastern New South Wales." Pacific Conservation Biology 2, no. 3 (1995): 299. http://dx.doi.org/10.1071/pc960299.

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A survey of conservation reserves, rainforest remnants and agricultural districts in northeastern New South Wales was conducted to determine the abundance, movements and habitat requirements of rainforest pigeons, to evaluate the extent and use of suitable habitat in conservation reserves, and to provide guidelines for the conservation and management of rainforest pigeons. Eight species of rainforest pigeon occur in northeastern New South Wales. Commencing with the clearing of rainforest in the 1860s for agriculture, rainforest pigeons declined in abundance throughout New South Wales and by the 1970s five species were thought to be threatened in the state. Since then, rainforest pigeons have apparently increased in abundance and distribution, but the Wompoo, Rose-crowned and Superb Pigeons continue to be listed by the New South Wales National Parks and Wildlife Service as vulnerable and rare. However, populations of all species of rainforest pigeons in New South Wales are relatively small and vulnerable to further loss of habitat. Most rainforest pigeons show a preference for subtropical rainforest habitat, but moist eucalypt forests, gardens and weedy exotic vegetation along roads and on abandoned farmland are also frequented to varying degrees by different species. To investigate recent trends in pigeon abundance we used data collected for up to 12 years from eight sites and during 1988, 1989 and 1990 from 17 rainforest remnants in northeastern New South Wales. The data suggest that rainforest pigeons now occur more frequently in lowland agricultural areas than in the recent past and tend to confirm an increase in abundance since the 1970s. Nesting and foraging habitats for rainforest pigeons are extensive in the conservation reserve system of northeastern New South Wales, but these habitats, which are largely at high elevations, lack winter food resources. Instead, pigeons congregate in remnant rainforest and exotic berry-bearing trees and shrubs in agricultural areas at lower elevations and near the coast. They rely on these habitats for food during winter and it is the restricted extent of this habitat that probably limits their abundance, not the area or quality of habitat at higher elevations. The conservation and management of rainforest pigeons requires the protection of low elevation and coastal rainforest remnants. As development of northeastern New South Wales proceeds, to avoid a decline in the abundances of rainforest pigeons it will be necessary to protect sclerophyll forest with native or exotic fruit bearing trees and shrubs and to extend the area of suitable habitat by the regeneration of rainforest and by the planting of native species used by pigeons as a food source. This will become increasingly important as the control and removal of exotic plants, such as Lantana Lantana camara and Camphor Laurel Cinnamonum camphora, on which some pigeons depend as a winter food source, becomes more successful.

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Kalio, G. A., U. I. Oji, and A. Larbi. "Preference and Palatability of Indigenous and Exotic Acid Soil-tolerant Multipurpose Trees and Shrubs by West African Dwarf Sheep." Agroforestry Systems 67, no. 2 (June 2006): 123–28. http://dx.doi.org/10.1007/s10457-005-4278-z.

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Journal articles on the topic 'Exotic shrubs'

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