Limited natural regeneration of unique Scalesia forest following invasive plant removal in Galapagos

More than 60% of the flora of the Galapagos Islands is introduced and some of these species have become invasive, severely altering ecosystems. An example of an affected ecosystem is the Scalesia forest, originally dominated by the endemic giant daisy tree Scalesia pedunculata (Asteraceae). The remnant patches of this unique forest are increasingly being invaded by introduced plants, mainly by Rubus niveus (blackberry, Rosaceae). To help large-scale restoration of this ecologically important forest, we seek to better understand the natural regeneration of S. pedunculata after invasive plant control. We monitored naturally recruited S. pedunculata saplings and young trees over five years in an area where invasive plant species are continuously being removed by manual means. We measured survival, height and growth of S. pedunculata saplings and young trees along permanent transects. Percent cover of surrounding plant species and of canopy shade directly above each S. pedunculata individual were determined, as well as distance to the next mature S. pedunculata tree. We identified potential factors influencing initial sapling survival and growth by applying generalized linear models. Results showed a rapid growth of saplings and young trees of up to 0.45 cm per day and a high mortality rate, as is typical for pioneer species like S. pedunculata. Sapling survival, growth and mortality seemed to be influenced by light availability, surrounding vegetation and distance to the next adult S. pedunculata tree. We concluded that natural regeneration of S. pedunculata was high only five months after the last herbicide application but that 95% of these recruits had died over the 5-year period. Further studies are needed to corroborate whether the number of surviving trees is sufficient to replace the aging adult trees and this way maintain remnants of the Scalesia forest. Urgent action is needed to help improve future restoration strategies to prevent further degradation of this rapidly shrinking threatened forest ecosystem.

Download Full-text

Ecological Impacts of Megaprojects: Species Succession and Functional Composition

Plants ◽

10.3390/plants10112411 ◽

2021 ◽

Vol 10 (11) ◽

pp. 2411

Author(s):

Hamada E. Ali ◽

Solveig Franziska Bucher

Keyword(s):

Plant Species ◽

Large Scale ◽

Invasive Plant ◽

Species Traits ◽

Natural Vegetation ◽

Ecological Impacts ◽

Imperata Cylindrica ◽

Dry Matter Content ◽

Large Scale Disturbance ◽

The Impact

Land-use changes have huge impacts on natural vegetation, especially megaprojects, as the vegetation layer is destroyed in the course of construction works affecting the plant community composition and functionality. This large-scale disturbance might be a gateway for the establishment of invasive plant species, which can outcompete the natural flora. In contrast, species occurring in the area before the construction are not able to re-establish. In this study, we analyzed the impact of a pipeline construction on a wetland nature reserve located in northern Egypt. Therefore, we analyzed the plant species occurrence and abundance and measured each plant species’ traits before the construction in 2017 as well as on multiple occasions up to 2 years after the construction had finished on altogether five sampling events. We found that the construction activity led to the establishment of an invasive species which previously did not occur in the area, namely, Imperata cylindrica, whereas five species (Ipomoea carnea, Pluchea dioscoridis, Polygonum equisetiforme, Tamarix nilotica, and Typha domingensis) could not re-establish after the disturbance. The functionality of ecosystems assessed via the analysis of plant functional traits (plant height, specific leaf area, and leaf dry matter content) changed within species over all sampling events and within the community showing a tendency to approximate pre-construction values. Functional dispersion and Rao’s quadratic diversity were higher after the megaproject than before. These findings are important to capture possible re-establishment and recovery of natural vegetation after construction and raise awareness to the impact of megaprojects, especially in areas which are high priority for conservation.

Download Full-text

Public Reaction to Invasive Plant Species in a Disturbed Colorado Landscape

Invasive Plant Science and Management ◽

10.1614/ipsm-d-09-00047.1 ◽

2010 ◽

Vol 3 (4) ◽

pp. 390-401 ◽

Cited By ~ 12

Author(s):

Michael T. Daab ◽

Courtney G. Flint

Keyword(s):

Plant Species ◽

Invasive Plants ◽

Large Scale ◽

Tree Mortality ◽

Invasive Plant ◽

Public Awareness ◽

Invasive Plant Species ◽

North Central ◽

The Public ◽

Large Scale Disturbance

AbstractInvasive plant species degrade ecosystems in many ways. Controlling invasive plants is costly for government agencies, businesses, and individuals. North central Colorado is currently experiencing large-scale disturbance, and millions of acres are vulnerable to invasion because of natural and socioeconomic processes. Mountain pine beetles typically endemic to this region have reached epidemic proportions, with up to 80% tree mortality, which opens growing space for invasive plants. In socioeconomic terms, the popularity of this amenity-rich region for tourists and in-migrants has resulted in increased development, often bordering the public land that is common in the American West. Increased recreational access and the construction of new roads and infrastructure disturb ecosystems in an increasingly fragmented landscape. A survey was mailed to more than 4,000 households in a five-county region of north central Colorado to gauge public awareness and attitudes regarding invasive plant species, helping to illuminate whether the public shows a capacity to help land managers detect and respond to invasive plants before they profoundly alter the local ecosystem. Although 88% of respondents had heard or read about invasive plant species, far fewer were familiar with specific, locally targeted species, and fewer still had taken any action to control these species. The overall awareness and concern about invasive plants in the area indicated a capacity for more public participation in management.

Download Full-text

Composting Invasive Plants in the Rio Grande River

Invasive Plant Science and Management ◽

10.1614/ipsm-d-13-00089.1 ◽

2014 ◽

Vol 7 (3) ◽

pp. 473-482 ◽

Cited By ~ 6

Author(s):

Erica J. Meier ◽

Tina M. Waliczek ◽

Michael L. Abbott

Keyword(s):

Invasive Species ◽

Plant Species ◽

Large Scale ◽

Invasive Plant ◽

Giant Reed ◽

Invasive Plant Species ◽

Whole Plant ◽

Germination And Growth ◽

Vegetative Propagules ◽

The U.S

AbstractThe purpose of this study was to determine the effect of whole-plant composting on the viability of seeds and other propagules of the invasive plant species waterhyacinth, waterlettuce, hydrilla, and giant reed while producing a valuable compost product. Invasive species were subjected to preliminary germination and growth tests and oven mortality tests to evaluate whether species distribution was via seeds, vegetative propagules, or both, as well as whether the composting process had the potential, through the high temperatures obtained, to kill seeds and other propagules. Germination and growth tests determined the means by which invasive species spread. Oven tests determined the temperatures at which unscarified and scarified seeds and propagules were rendered inviable. Achieving temperatures of at least 57.2 C was necessary within constructed compost piles to effectively kill the plants without the danger of redistribution. In the field, the study successfully developed a large-scale composting operation using invasive plant species as the primary feedstock. Analysis of field-scale composting showed final materials were within satisfactory to ideal levels for samples analyzed by the U.S. Compost Council's Seal of Testing Assurance Program and were, therefore, a valuable compost product.

Download Full-text

Hurricane Activity and the Large-Scale Pattern of Spread of an Invasive Plant Species

PLoS ONE ◽

10.1371/journal.pone.0098478 ◽

2014 ◽

Vol 9 (5) ◽

pp. e98478 ◽

Cited By ~ 23

Author(s):

Ganesh P. Bhattarai ◽

James T. Cronin

Keyword(s):

Plant Species ◽

Large Scale ◽

Invasive Plant ◽

Invasive Plant Species ◽

Hurricane Activity

Download Full-text

EFFECTS OF THE ABUNDANCE OF PARTHENIUM HYSTEROPHORUS ON THE COMPOSITION AND DIVERSITY OF OTHER HERBACEOUS PLANT SPECIES IN SIMANJIRO RANGELAND, TANZANIA

International Journal of Engineering Technologies and Management Research ◽

10.29121/ijetmr.v7.i5.2020.631 ◽

2020 ◽

Vol 7 (5) ◽

pp. 11-20

Author(s):

Leticia J. Musese ◽

Samora M. Andrew ◽

Deo D. Shirima ◽

Arne Witt ◽

Ramadhan Kilewa

Keyword(s):

Plant Species ◽

Invasive Plant ◽

Linear Models ◽

Similarity Index ◽

Parthenium Hysterophorus ◽

Herbaceous Plant ◽

Potential Threat ◽

Significant Difference ◽

Abundance And Diversity ◽

Jaccard's Similarity Index

Parthenium hysterophorus is an annual herbaceous plant native to tropical America; and an invasive plant in Africa causing distressing effects on natural flora. This study investigated the effects of P. hysterophorus on the composition and diversity of native herbaceous plant species in Simanjiro rangeland, Tanzania. Plant species count data were collected from 60 (1m2) quadrats. Using generalized linear models (GLM), the abundance of P. hysterophorus was regressed against the abundance and diversity of the native herbaceous plants. Also, Jaccard’s similarity index was used to compare species composition. Results showed that there were 14 herbaceous plant species belonging to 13 genera and 10 families in the study area. Parthenium hysterophorus was the most dominant species recorded. The abundance of P. hysterophorus has a substantial negative effect on the abundance and diversity of other herbaceous plant species. Moreover, Jaccard’s similarity index showed a slightly significant difference between the infested and non-infested areas. This finding suggests that P. hysterophorus has a substantial potential threat on other herbaceous flora which are sources of food and nutrients to livestock and wild animals in the area. Thus, integrated management strategies are required to control the weed from spreading to other nearby rangelands.

Download Full-text

Combining local- and large-scale models to predict the distributions of invasive plant species

Ecological Applications ◽

10.1890/08-2261.1 ◽

2010 ◽

Vol 20 (2) ◽

pp. 311-326 ◽

Cited By ~ 59

Author(s):

Chad C. Jones ◽

Steven A. Acker ◽

Charles B. Halpern

Keyword(s):

Plant Species ◽

Large Scale ◽

Invasive Plant ◽

Invasive Plant Species ◽

Scale Models

Download Full-text

Invasive Earthworms and Plants in Indiana Old- and Second-Growth Forests

Invasive Plant Science and Management ◽

10.1614/ipsm-d-12-00046.1 ◽

2013 ◽

Vol 6 (1) ◽

pp. 161-174 ◽

Cited By ~ 3

Author(s):

Kevin D. Gibson ◽

Patricia M. Quackenbush ◽

Nancy C. Emery ◽

Michael A. Jenkins ◽

Eileen J. Kladivko

Keyword(s):

Plant Species ◽

Invasive Plant ◽

Stand Structure ◽

Hardwood Forests ◽

Percent Cover ◽

Native Plant ◽

Native Plant Species ◽

Second Growth ◽

Multiflora Rose ◽

Understory Plant

AbstractHardwood forests in eastern North America are being colonized by multiple nonnative plant and animal species. Colonization rates can be affected by stand structure and distance from edge. We sampled earthworm densities and understory plant species cover in transects located in paired old- and second-growth forests in Indiana. Two 100-m transects were established within each forest stand during late April to early May in each year. One transect was placed parallel to and within 5 m of a south- or west-facing edge. The second transect was placed parallel to the first. but at no less than 100 m from any edge. Nonnative earthworms and plants were found in forest edge and interior regardless of structural stage (second-growth vs. old-growth). The number of native plant species decreased linearly as the densities of adult Lumbricus and Aporrectodea earthworms and the percent cover of multiflora rose (an invasive plant species) increased. Densities of L. terrestris and Aporrectodea earthworms and percent cover of multiflora rose cumulatively explained 39% of the variation in the number of native plant species found in transects across the state. However, multivariate analyses suggested that the species composition of Indiana understory plant communities was affected more by geography than by earthworm densities. Our results suggest that nonnative earthworms and plants are ubiquitous in Indiana hardwood forests and that they may reduce the number of native plant species.

Download Full-text

Trait differentiation between native and introduced populations of the invasive plant Sonchus oleraceus L. (Asteraceae)

NeoBiota ◽

10.3897/neobiota.55.49158 ◽

2020 ◽

Vol 55 ◽

pp. 85-115

Author(s):

Melodie Ollivier ◽

Elena Kazakou ◽

Maxime Corbin ◽

Kevin Sartori ◽

Ben Gooden ◽

...

Keyword(s):

Grain Yield ◽

Plant Species ◽

Dry Matter ◽

Invasive Plant ◽

Native Plants ◽

Germination Rate ◽

Invasive Plant Species ◽

Stem Biomass ◽

Sonchus Oleraceus ◽

Introduced Plants

There is growing evidence that rapid adaptation to novel environments drives successful establishment and spread of invasive plant species. However, the mechanisms driving trait adaptation, such as selection pressure from novel climate niche envelopes, remain poorly tested at global scales. In this study, we investigated differences in 20 traits (relating to growth, resource acquisition, reproduction, phenology and defence) amongst 14 populations of the herbaceous plant Sonchus oleraceus L. (Asteraceae) across its native (Europe and North Africa) and introduced (Australia and New Zealand) ranges. We compared traits amongst populations grown under standard glasshouse conditions. Introduced S. oleraceus plants seemed to outperform native plants, i.e. possessing higher leaf and stem dry matter content, greater number of leaves and were taller at first flowering stage. Although introduced plants produced fewer seeds, they had a higher germination rate than native plants. We found strong evidence for adaptation along temperature and precipitation gradients for several traits (e.g. shoot height, biomass, leaf and stem dry matter contents increased with minimum temperatures, while germination rate decreased with annual precipitations and temperatures), which suggests that similar selective forces shape populations in both the native and invaded ranges. We detected significant shifts in the relationships (i.e. trade-offs) (i) between plant height and flowering time and (ii) between leaf-stem biomass and grain yield between native and introduced plants, indicating that invasion was associated with changes to life-history dynamics that may confer competitive advantages over native vegetation. Specifically, we found that, at first flowering, introduced plants tended to be taller than native ones and that investment in leaf and stem biomass was greater in introduced than in native plants for equivalent levels of grain yield. Our study has demonstrated that climatic conditions may drive rapid adaption to novel environments in invasive plant species.

Download Full-text