Rubus alceifolius (giant bramble).

2021 ◽  
Author(s):  
Chris Parker
Keyword(s):  
Wind Damage ◽  
Primary Forest ◽  
Invasive Weeds ◽  
La Réunion ◽  
Joint Project ◽  
Plant Invaders ◽  
Indian Ocean Island ◽  
The Indian Ocean ◽  
Risk Of Wind Damage ◽  
The Tropics

Abstract R. alceifolius is a robust, aggressive perennial scrambling shrub, spreading by long arching spiny stems, rooting at their tips, as well as by bird-dispersed seeds. It can develop dense impenetrable thickets. It is native to tropical SE Asia but has been introduced to a number of other territories, most notably the Indian Ocean island of La Réunion, where it is one of the eight most threatening plant invaders to become established on the island and occurs not only on sites disturbed by man but also in primary forest with minimal disturbance (Macdonald et al., 1991). It can behave as a liana, climbing into the canopy of forest trees and increasing the risk of wind damage. It occurs also on the islands of Mayotte, Mauritius and Madagascar (Vos, 2004; Kueffer and Lavergne, 2004a,b) and in Queensland, Australia where it is invading pastures, roadsides, creekbanks, sugarcane plantations and the edges of rainforest (Queensland Government, 2012). Holm et al. (1979) record it as a 'principal' weed in Australia, and risk assessment by the Australian method gave a score of 11 (PIER, 2012). Binggeli et al. (1998) classified it as highly invasive in the tropics. In a joint project between USDA and the Weed Science Society of America it was identified among the highest-ranked potential future invasive weeds in USA (Parker et al., 2007; WSSA, 2012).

Life-style services and yield from south-Swedish forests adaptively managed against the risk of wind damage: a simulation study

2014 ◽  
Vol 15 (8) ◽  
pp. 1489-1500 ◽  
Author(s):  
Mikael Andersson ◽  
Seppo Kellomäki ◽  
Barry Gardiner ◽  
Kristina Blennow
Keyword(s):  
Simulation Study ◽  
Life Style ◽  
Wind Damage ◽  
Risk Of Wind Damage

scholarly journals Triggering the Indian Ocean Dipole from the Southern Hemisphere

2021 ◽  
Author(s):  
Lian-Yi Zhang ◽  
Yan Du ◽  
Wenju Cai ◽  
Zesheng Chen ◽  
Tomoki Tozuka ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Southern Hemisphere ◽  
Indian Ocean Dipole ◽  
Southern Oscillation ◽  
Southern Annular Mode ◽  
Triggering Mechanism ◽  
Phase Development ◽  
The Indian Ocean ◽  
High System ◽  
The Tropics

<p>This study identifies a new triggering mechanism of the Indian Ocean Dipole (IOD) from the Southern Hemisphere. This mechanism is independent from the El Niño/Southern Oscillation (ENSO) and tends to induce the IOD before its canonical peak season. The joint effects of this mechanism and ENSO may explain different lifetimes and strengths of the IOD. During its positive phase, development of sea surface temperature cold anomalies commences in the southern Indian Ocean, accompanied by an anomalous subtropical high system and anomalous southeasterly winds. The eastward movement of these anomalies enhances the monsoon off Sumatra-Java during May-August, leading to an early positive IOD onset. The pressure variability in the subtropical area is related with the Southern Annular Mode, suggesting a teleconnection between high-latitude and mid-latitude climate that can further affect the tropics. To include the subtropical signals may help model prediction of the IOD event.</p>

Biotic resistance to plant invasions.

2020 ◽  
pp. 177-191
Author(s):  
John D. Parker ◽  
◽  
John L. Devaney ◽  
Nathan P. Lemoine ◽  
◽  
...  
Keyword(s):  
Biotic Resistance ◽  
Propagule Pressure ◽  
Empirical Support ◽  
Plant Invasions ◽  
Plant Invaders ◽  
History Of Research ◽  
History Of ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts ◽  
The Tropics

Biotic resistance to plant invasions takes many forms: consumption by native herbivores, competition with native plants and infection by native pathogens. But how often does biotic resistance prevent the damaging monocultures that typify the most problematic plant invaders, and how often is biotic resistance overwhelmed by the direct and indirect impacts of human activities? This chapter attempts to answer these questions, drawing on the long history of research into biotic resistance. We first briefly describe the major forms of biotic resistance to exotic plant invasions as an antecedent to other, more detailed chapters on competition, herbivory and pathogens. We then describe a new neutral model where variance in disturbance promotes invasions over the short term, but over longer timescales only propagule pressure drives invasions. These findings are a cautionary tale; pending increases in global trade and travel, particularly to the tropics, may provide the prerequisite disturbance and propagule pressure needed to ultimately stoke further invasions. Finally, we highlight case studies where invasions have been mitigated by restoration of biotic resistance from native herbivores and competitors. These studies provide strong empirical support that conservation of native biodiversity can be a nature-based solution to some invasions, although it remains to be seen if climate change will alter these effects over longer timescales.

scholarly journals Does Variable-Density Thinning Increase Wind Damage in Conifer Stands on the Olympic Peninsula?

2007 ◽  
Vol 22 (4) ◽  
pp. 285-296 ◽  
Author(s):  
Scott D. Roberts ◽  
Constance A. Harrington ◽  
Karl R. Buermeyer
Keyword(s):  
Structural Diversity ◽  
Variable Density ◽  
Canopy Gaps ◽  
Wind Damage ◽  
Olympic Peninsula ◽  
Growing Seasons ◽  
Silvicultural Treatments ◽  
Stand Structural Diversity ◽  
Risk Of Wind Damage ◽  
Damage Risk

Abstract Silvicultural treatments designed to enhance stand structural diversity may result in increased wind damage. The ability to avoid conditions that might lead to excessive wind damage would benefit forest managers. We analyzed wind damage following implementation of a variable-density thinning at four sites on the Olympic National Forest in northwest Washington. The prescription created small canopy gaps and retained unthinned patches within a uniformly thinned matrix, thus creating substantial amounts of internal edge. Our objective was to determine whether variable-density thinning resulted in elevated wind damage and whether the damage was spatially related to elements of the treatment, i.e., canopy gaps and uncut patches. Wind damage on the thinned plots averaged slightly more than 8.0 trees/ha. Although precise determinations of residual stem densities were not available, we estimate that total wind damage amounted to 1.3% of total stems remaining following treatment. Approximately 80% of the wind damage was blowdown, the remaining damage being stem breakage, leaning, or bowing. Nearly 54% of the damaged stems were less than 20 cm dbh. The maximum amount of damage observed was 51 trees/ha, but only 3 of 13 thinned plots had wind damage exceeding 7 trees/ha. The overall level of wind damage across all thinned plots after two growing seasons was not statistically greater than on unthinned control plots. Internal edges created by gaps, skid trails, and unthinned patches did not inherently increase wind damage risk; however, where gaps were located in topographically vulnerable positions, greater wind damage did occur. Overall wind damage was not excessive on any of the plots, and after 2 years, all residual stands remained intact and in a manageable condition. Our preliminary results suggest that variable-density thinning that includes creation of small canopy gaps does not necessarily predispose stands to greater risk of wind damage than uniform thinning. However, care must be taken in locating gaps and skid trails away from topographically vulnerable positions.

scholarly journals Similarities in Leptospira Serogroup and Species Distribution in Animals and Humans in the Indian Ocean Island of Mayotte

2012 ◽  
Vol 87 (1) ◽  
pp. 134-140 ◽  
Author(s):  
Amélie Desvars ◽  
Florence Naze ◽  
Gwenaël Vourc'h ◽  
Alain Michault ◽  
Eric Cardinale ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Species Distribution ◽  
Ocean Island ◽  
Indian Ocean Island ◽  
The Indian Ocean

Seasonal variations in the Indian Ocean along 110°E. I. Hydrological structure of the upper 500 m

1969 ◽  
Vol 20 (1) ◽  
pp. 1 ◽  
Author(s):  
DJ Rochford
Keyword(s):  
Indian Ocean ◽  
Surface Waters ◽  
Water Masses ◽  
Surface Currents ◽  
Temperature Changes ◽  
East Indian ◽  
Hydrological Structure ◽  
The Indian Ocean ◽  
The Tropics ◽  
East Indian Ocean

Tropical and subtropical water masses at surface and subsurface depths were separated by their salinity, temperature, oxygen, and nutrient characteristics. The annual mean depths and latitudinal extent of these water masses were determined. Annual changes in the upper 50 m were generally so small relative to those found in other oceans that advection and mixing must have been less important in their genesis than local climatic changes. There was a barely significant seasonal rhythm in surface phosphate and nitrate, with peak occurrences of each some 6 months apart. At each latitude the permanent thermal discontinuity centred around a particular isotherm varied little in intensity during the year, but rose and fell in accordance with surface currents. The thermocline south of c. 18�S. varied little in depth but greatly in intensity during the summer. The depth of the mixed layer was much less in summer and at all times shallower in the tropics. The depth of this layer was governed more by the accumulation of surface waters by zonal currents and eddies, than by wind stress or convective overturn. Therefore there was little difference from south to north, or month to month, in average nutrient values of this mixed column. The movement of the various surface waters, deduced from salinity and temperature changes during the year, usually agrees with geostrophic currents across 110�E, and ships' observations of surface currents in the south-east Indian Ocean.

India’s Strategic Interests and Partnership with Island States of Africa in the Western Indian Ocean Region

2020 ◽  
Vol 7 (2) ◽  
pp. 227-243
Author(s):  
Raghvendra Kumar
Keyword(s):  
Indian Ocean ◽  
Western Indian Ocean ◽  
Power Dynamics ◽  
Indian Ocean Region ◽  
Island States ◽  
Global Power ◽  
Challenges And Opportunities ◽  
Ocean Region ◽  
Indian Ocean Island ◽  
The Indian Ocean

The Indian Ocean has turned into the new geographical centre of power, where global power dynamics is being revealed. It has been transformed into a geostrategic heartland, forecasting new challenges and opportunities, and at the core of this is an emerging power, India, which, being located at a strategic juncture in the Indian Ocean, shapes much of this geostrategic transformation. Therefore, sustaining and improving security and continuing economic expansion, with an increased strategic presence in the region to safeguard its national, regional and global interests are some of the elements which greatly influence India’s involvement with the strategic island states of Africa in the Western Indian Ocean Region. In this backdrop, this article has tried to contextualise the ‘Western Indian Ocean Region’ and ‘situate the actors’ to explore the various contours of geostrategic engagements the region is witnessing. Further, the article examines India’s strategic interests in the Western Indian Ocean, which are critical for its global power aspirations. It discusses the linkages between India and the Western Indian Ocean island states of Africa, which would become the precursor for newer strategies and help in harnessing the potential of mutually beneficial cooperation. Lastly, the article seeks to re-engage with the island states of Africa to help forge a deeper cultural and strategic bond, which would be crucial in balancing the power equation in the region.

Integrating the risk of wind damage into forest planning

2009 ◽  
Vol 258 (7) ◽  
pp. 1567-1577 ◽  
Author(s):  
T. Heinonen ◽  
T. Pukkala ◽  
V.-P. Ikonen ◽  
H. Peltola ◽  
A. Venäläinen ◽  
...  
Keyword(s):  
Wind Damage ◽  
Forest Planning ◽  
Risk Of Wind Damage

Interactions of the Indian Ocean climate with other tropical oceans

2020 ◽  
Author(s):  
Matthieu Lengaigne ◽  
Keyword(s):  
Indian Ocean ◽  
Climate Variability ◽  
Future Climate ◽  
Future Climate Change ◽  
The Pacific ◽  
Ocean Atmosphere ◽  
The Indian Ocean ◽  
The Tropics ◽  
Modes Of Climate Variability ◽  
The Tropical Pacific

<p>Ocean-atmosphere interactions in the tropics have a profound influence on the climate system. El Niño–Southern Oscillation (ENSO), which is spawned in the tropical Pacific, is the most prominent and well-known year-to-year variation on Earth. Its reach is global, and its impacts on society and the environment are legion. Because ENSO is so strong, it can excite other modes of climate variability in the Indian Ocean by altering the general circulation of the atmosphere. However, ocean-atmosphere interactions internal to the Indian Ocean are capable of generating distinct modes of climate variability as well. Whether the Indian Ocean can feedback onto Atlantic and Pacific climate has been an on-going matter of debate. We are now beginning to realize that the tropics, as a whole, are a tightly inter-connected system, with strong feedbacks from the Indian and Atlantic Oceans onto the Pacific. These two-way interactions affect the character of ENSO and Pacific decadal variability and shed new light on the recent hiatus in global warming.</p><p>Here we review advances in our understanding of pantropical interbasins climate interactions with the Indian Ocean and their implications for both climate prediction and future climate projections. ENSO events force changes in the Indian Ocean than can feed back onto the Pacific. Along with reduced summer monsoon rainfall over the Indian subcontinent, a developing El Niño can trigger a positive Indian Ocean Dipole (IOD) in fall and an Indian Ocean Basinwide (IOB) warming in winter and spring. Both IOD and IOB can feed back onto ENSO. For example, a positive IOD can favor the onset of El Niño, and an El Niño–forced IOB can accelerate the demise of an El Niño and its transition to La Niña. These tropical interbasin linkages however vary on decadal time scales. Warming during a positive phase of Atlantic Multidecadal Variability over the past two decades has strengthened the Atlantic forcing of the Indo-Pacific, leading to an unprecedented intensification of the Pacific trade winds, cooling of the tropical Pacific, and warming of the Indian Ocean. These interactions forced from the tropical Atlantic were largely responsible for the recent hiatus in global surface warming.</p><p>Climate modeling studies to address these issues are unfortunately compromised by pronounced systematic errors in the tropics that severely suppress interactions with the Indian and Pacific Oceans. As a result, there could be considerable uncertainty in future projections of Indo-Pacific climate variability and the background conditions in which it is embedded. Projections based on the current generation of climate models suggest that Indo-Pacific mean-state changes will involve slower warming in the eastern than in the western Indian Ocean. Given the presumed strength of the Atlantic influence on the pantropics, projections of future climate change could be substantially different if systematic model errors in the Atlantic were corrected. There is hence tremendous potential for improving seasonal to decadal climate predictions and for improving projections of future climate change in the tropics though advances in our understanding of the dynamics that govern interbasin linkages.</p>

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