Landscape-scale disturbances and regeneration in semi-arid woodlands of southwestern Australia

1994 ◽  
Vol 1 (3) ◽  
pp. 214 ◽  
Author(s):  
Colin J. Yates ◽  
Richard J. Hobbs ◽  
Richard W. Bell
Keyword(s):  
Tree Mortality ◽  
Landscape Scale ◽  
Eucalyptus Species ◽  
Natural Ecosystems ◽  
Fragmented Landscapes ◽  
The Past ◽  
Adult Tree ◽  
Western Australian ◽  
Semi Arid

Woodlands dominated by Eucalyptus salmonophloia occur both in the fragmented landscapes of the Western Australian wheatbelt and in the adjacent unfragmented goldfields area. We examined the responses of the unfragmented woodlands to landscape-scale disturbances caused by fire, floods, windstorms and drought. Sites known to have experienced disturbances of these types over the past 50 years all had cohorts of sapling-stage E. salmonophloia and other dominant Eucalyptus species. Sites disturbed either by fire, flood or storm during 1991-92 displayed adult tree mortality and extensive seedling establishment, although rates of establishment and survival varied between sites. No regeneration was observed at equivalent undisturbed sites. These results indicate that landscape-scale disturbances of several types are important drivers of the dynamics of these semi-arid woodlands. Lack of regeneration of fragmented woodlands in the wheatbelt is likely to be due to changed disturbance regimes coupled with altered physical and biotic conditions within remnants. We argue that it may be difficult to identify processes which are important for the long-term persistence of natural ecosystems in fragmented landscapes without reference to equivalent unfragmented areas.

Impact of wetland disturbance on phosphorus loadings to lakes

2014 ◽  
Vol 71 (11) ◽  
pp. 1695-1703 ◽  
Author(s):  
Kieran C. Pinder ◽  
M. Catherine Eimers ◽  
Shaun A. Watmough
Keyword(s):  
Tree Mortality ◽  
Field Surveys ◽  
The Past ◽  
South Central ◽  
Tree Community ◽  
Dead Trees ◽  
Standing Dead ◽  
Mixed Age ◽  
Wetland Cover

Total phosphorus (TP) concentrations have declined in many lakes and streams across south-central Ontario, Canada, over the past three decades, and changes have been most pronounced in wetland-dominated catchments. In this study, long-term (1980–2007) patterns in TP concentrations in streams were assessed at four wetland-dominated catchments that drain into Dickie Lake (DE) in south-central Ontario. Two of the subcatchments (DE5 and DE6) have particularly large wetland components (31%–34% of catchment area), and these wetlands are characterized by numerous standing dead trees and many young live trees (18–27 years old). These two streams exhibited large peaks in TP and potassium (K) export in the early 1980s. In contrast, TP and K export from DE8 and DE10 (wetland cover 19%–20%) were relatively flat over the entire record (1980–2007), and field surveys indicated negligible standing dead biomass in these wetlands and a relatively healthy, mixed-age tree community. The coincidence of high TP and K concentrations in the DE5 and DE6 streams as well as evidence of a disturbance event in their wetlands during the early 1980s suggest that disturbance events (e.g., flooding) that lead to wetland tree mortality may contribute to patterns in surface water TP observed in this region.

A multi-century spring precipitation history for northern Iran derived from tree-ring δ18O 

2021 ◽  
Author(s):  
Zeynab Foroozan ◽  
Jussi Grießinger ◽  
Kambiz Pourtahmasi ◽  
Achim Bräuning
Keyword(s):  
Tree Ring ◽  
Large Scale ◽  
Regional Climate ◽  
Spring Precipitation ◽  
Northern Iran ◽  
The Past ◽  
Precipitation Record ◽  
Hydroclimatic Variability ◽  
Semi Arid

<p>Knowledge about the long-term hydroclimatic variability is essential to analyze the historic course and recent impact of climate change, especially in semi-arid and arid regions of the world. In this study, we present the first tree-ring δ<sup>18</sup>O chronology for the semi-arid parts of northern Iran based on juniper trees. We were able to reconstruct past hydroclimatic variability for the past 500 years. The highly significant correlation between tree-ring δ<sup>18</sup>O and spring precipitation indicates the primary influence of spring moisture availability on δ<sup>18</sup>O variations. The thereof derived precipitation reconstruction reveals short and long-term variability of precipitation intensity, duration, and frequency of dry/wet events. During the past 500 years, the driest period occurred in the 16<sup>th</sup> century, whereas the 18th century was comparably wet. A gradual decline in the reconstructed spring precipitation is evident since the beginning of the 19th century, culminating in the continuing drought of the 20<sup>th</sup> century. An analysis of dry/wet years indicated that over the last three centuries, the occurrence of years with a relatively dry spring is increasing. In contrast, more humid spring conditions are decreasing. However, the overall frequency of the occurrence of extreme events increased over the past five centuries. In addition, past hydrological disasters recorded in Persian history were well represented in our reconstruction. Correlations between our reconstructed precipitation record and large-scale circulation systems revealed no significant influence of large-scale climatic drivers on spring precipitation variations in north Iran, which therefore seem to be mostly controlled by a regional climate forcing.</p>

Continuing Long-Term Studies of the Tropics Panama Oil and Dispersed Oil Spill Sites

2003 ◽  
Vol 2003 (1) ◽  
pp. 259-267 ◽  
Author(s):  
Greg A. Ward ◽  
Bart Baca ◽  
Wendy Cyriacks ◽  
Richard E. Dodge ◽  
Anthony Knap
Keyword(s):  
Crude Oil ◽  
Oil Spill ◽  
Tree Mortality ◽  
Oil Pollution ◽  
Bocas Del Toro ◽  
The Past ◽  
Dispersed Oil ◽  
Present Information ◽  
The Tropics

ABSTRACT The TROPICS (Tropical Oil Pollution Investigations in Coastal Systems) oil spill experiment was conducted on the Caribbean coast of Panama, near Bocas del Toro. In November 1984, crude and dispersed crude oil were released in two separate boom-enclosed areas representative of intertidal mangrove and subtidal seagrass/coral ecosystems. The present information is based on site visits over the past two years, including 2002. Following the degradation of oil over the past 18 years, sheen identified from the spilled oil in 1994 is still visible in non-dispersed Oil Site sediments. In mangroves, previously denuded areas exposed to crude oil are currently occupied by new seedlings and saplings, which are growing rapidly but with morphological prop-root deformations. Tree mortality occurred in both the Dispersed Oil and Reference Sites, but was non-localized and appeared as natural mortality in aged trees. Recent data have revealed an invasion of seagrass beds by finger coral at the Oil Site. Since treatment, percent coverage of corals at this site has grown from a pretreatment value of 33.5% in March 1984 to 67.5% in June 2001.

Lethal biological control of rabbits – the most powerful tools for landscape-scale mitigation of rabbit impacts in Australia

2019 ◽  
Vol 40 (1) ◽  
pp. 118-128 ◽  
Author(s):  
Tanja Strive ◽  
Tarnya E. Cox
Keyword(s):  
Population Control ◽  
Landscape Scale ◽  
Myxoma Virus ◽  
Effective Control ◽  
Rabbit Haemorrhagic Disease Virus ◽  
The Past ◽  
Rabbit Haemorrhagic Disease ◽  
Domestic Rabbits ◽  
Haemorrhagic Disease

ABSTRACT The viral biocontrol agents Myxoma virus (MYXV) and Rabbit Haemorrhagic Disease Virus (RHDV1), released in 1950 and 1996 respectively, are the only control tools to have resulted in significant and lasting landscape-scale suppression of rabbit populations in Australia. Multiple conservation benefits and significant economic savings have resulted from the long-term and widespread reductions in rabbit numbers and impacts. In an effort to ‘boost’ rabbit biocontrol, an additional variant of RHDV1 ('K5') was recently released nationwide to counteract the decreasing effectiveness of both RHDV1 and MYXV that results from the evolutionary ‘arms race’ between viruses and their hosts. Two years prior to the K5 release, an exotic RHDV strain (RHDV2) appeared in Australia. The commercially available vaccine used to protect pet and farmed rabbits against the officially released K5 was ineffective against the exotic RHDV2, resulting in numerous deaths of domestic rabbits. This created substantial confusion about which strain was released as a biocontrol tool, as well as renewed concerns amongst pet rabbit owners and rabbit farmers about the use of viruses as lethal rabbit control tools in general. Ongoing effective control of wild rabbits in Australia is absolutely essential to protect the substantial conservation gains made by the long-term suppression of rabbit numbers over the past decades, and there is currently no alternative population control tool to achieve this at the required landscape scale. Vaccine formulations need updating to protect non-target farmed and pet rabbits from circulating field variants, including RHDV2, and to increase public acceptance for the ongoing use of viral biocontrol for feral rabbit populations.

Two Hundred Years of Land Use and Vegetation Change in a Remnant Coastal Woodland in Southern Australia

1998 ◽  
Vol 46 (6) ◽  
pp. 629 ◽  
Author(s):  
Ian D. Lunt
Keyword(s):  
Land Use ◽  
Vegetation Change ◽  
Eucalyptus Species ◽  
Ecological Studies ◽  
The Past ◽  
Fire Exclusion ◽  
Settlement Changes ◽  
Term Response ◽  
Aboriginal Burning

Post-settlement changes in vegetation and land use were examined in a reputedly undisturbed woodland remnant at Ocean Grove, southern Victoria, the site of earlier ecological studies. The vegetation has passed through at least three structural phases since European colonisation: an open grassy woodland dominated by Allocasuarina and Eucalyptus species and Banksia marginata Cav. with few shrubs; an open scrub of Acacia pycnantha Benth.; and a closed scrub of Allocasuarina littoralis (Salisb.) L.A.S.Johnson, which now dominates the reserve. Tree and shrub density has progressively increased, from perhaps less than 20 trees ha–1 in the early 1800s, to over 3000 trees ha–1 in 1996. Most large Allocasuarina trees established in the late 1930s or early 1940s, and Allocasuarina littoralis appears to have invaded rapidly thereafter. Surprisingly, A. littoralis was not recorded in an 1894 plant census, and might have been locally rare last century. Vegetation changes over the past 200 years can be attributed to the long-term absence of fire. The abundant recruitment of Acacia species in the mid- to late-1800s may have been a rapid response to the curtailment of Aboriginal burning, and the more recent invasion of A. littoralis a longer-term response to fire exclusion. The importance of active vegetation management for biodiversity conservation in the future is stressed.

Enabling Community Well-being Self-Monitoring in the Context of Mining: The Naskapi Nation of Kawawachikamach

2016 ◽  
Vol 1 (2) ◽  
Author(s):  
Robert Klinck ◽  
Ben Bradshaw ◽  
Ruby Sandy ◽  
Silas Nabinacaboo ◽  
Mannie Mameanskum ◽  
...  
Keyword(s):  
Indigenous Peoples ◽  
Well Being ◽  
Aboriginal Community ◽  
Self Monitoring ◽  
Community Engaged Research ◽  
The Past ◽  
Mineral Development ◽  
Iron Deposits ◽  
Term Monitoring

The Naskapi Nation of Kawawachikamach is an Aboriginal community located in northern Quebec near the Labrador Border. Given the region’s rich iron deposits, the Naskapi Nation has considerable experience with major mineral development, first in the 1950s to the 1980s, and again in the past decade as companies implement plans for further extraction. This has raised concerns regarding a range of environmental and socio-economic impacts that may be caused by renewed development. These concerns have led to an interest among the Naskapi to develop a means to track community well-being over time using indicators of their own design. Exemplifying community-engaged research, this paper describes the beginning development of such a tool in fall 2012—the creation of a baseline of community well-being against which mining-induced change can be identified. Its development owes much to the remarkable and sustained contribution of many key members of the Naskapi Nation. If on-going surveying is completed based on the chosen indicators, the Nation will be better positioned to recognize shifts in its well-being and to communicate these shifts to its partners. In addition, long-term monitoring will allow the Naskapi Nation to contribute to more universal understanding of the impacts of mining for Indigenous peoples.

Courting the Youth Vote in 2008: The Obama Effect

2009 ◽  
Vol 5 ◽  
Author(s):  
Lindsey C Bohl
Keyword(s):  
Presidential Elections ◽  
Voter Registration ◽  
The Internet ◽  
The Past ◽  
Several Variables ◽  
High Turnout ◽  
Short And Long Term ◽  
Use Of The Internet ◽  
Youth Vote

This paper examines a few of the numerous factors that may have led to increased youth turnout in 2008 Election. First, theories of voter behavior and turnout are related to courting the youth vote. Several variables that are perceived to affect youth turnout such as party polarization, perceived candidate difference, voter registration, effective campaigning and mobilization, and use of the Internet, are examined. Over the past 40 years, presidential elections have failed to engage the majority of young citizens (ages 18-29) to the point that they became inclined to participate. This trend began to reverse starting in 2000 Election and the youth turnout reached its peak in 2008. While both short and long-term factors played a significant role in recent elections, high turnout among youth voters in 2008 can be largely attributed to the Obama candidacy and campaign, which mobilized young citizens in unprecedented ways.

Impact of FII’s and FDI’s on Indian Stock Market

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Dr. Kamlesh Kumar Shukla
Keyword(s):  
Stock Market ◽  
Financial Markets ◽  
Global Economy ◽  
Short Term ◽  
Earnings Growth ◽  
The Past ◽  
Bull Market ◽  
Indian Stock Market

FIIs are companies registered outside India. In the past four years there has been more than $41 trillion worth of FII funds invested in India. This has been one of the major reasons on the bull market witnessing unprecedented growth with the BSE Sensex rising 221% in absolute terms in this span. The present downfall of the market too is influenced as these FIIs are taking out some of their invested money. Though there is a lot of value in this market and fundamentally there is a lot of upside in it. For long-term value investors, there’s little because for worry but short term traders are adversely getting affected by the role of FIIs are playing at the present. Investors should not panic and should remain invested in sectors where underlying earnings growth has little to do with financial markets or global economy.

Chinese Medicine Protein and Peptide in Gene and Cell Therapy

2019 ◽  
Vol 20 (3) ◽  
pp. 251-264 ◽  
Author(s):  
Yinlu Feng ◽  
Zifei Yin ◽  
Daniel Zhang ◽  
Arun Srivastava ◽  
Chen Ling
Keyword(s):  
Chinese Medicine ◽  
Cell Therapy ◽  
Future Research ◽  
The Past ◽  
Promising Strategy ◽  
Wide Range ◽  
New Directions ◽  
Gene And Cell Therapy ◽  
Proteins And Peptides

The success of gene and cell therapy in clinic during the past two decades as well as our expanding ability to manipulate these biomaterials are leading to new therapeutic options for a wide range of inherited and acquired diseases. Combining conventional therapies with this emerging field is a promising strategy to treat those previously-thought untreatable diseases. Traditional Chinese medicine (TCM) has evolved for thousands of years in China and still plays an important role in human health. As part of the active ingredients of TCM, proteins and peptides have attracted long-term enthusiasm of researchers. More recently, they have been utilized in gene and cell therapy, resulting in promising novel strategies to treat both cancer and non-cancer diseases. This manuscript presents a critical review on this field, accompanied with perspectives on the challenges and new directions for future research in this emerging frontier.

Organizational Reforms as Routines

2017 ◽  
Author(s):  
Nils Brunsson
Keyword(s):  
Long Term Effects ◽  
The Past ◽  
Limited Experience

This chapter argues that organizational reforms are driven by problems to be addressed, by solutions to be applied, and by forgetfulness. The greater the supply of any of these factors, the more likely it is that reforms will occur. Without problems, reforms are difficult to justify; without solutions they cannot be formulated; and without forgetfulness there is a risk that people will be discouraged by the fact that similar reforms have been tried and have failed in the past. In contemporary large organizations, problems tend to be easily found. Those interested in selling solutions often try to supply problems as well — problems that can be solved by their solutions. Forgetfulness can be promoted by the use of consultants with limited experience of the implementation and long-term effects of reforms. Reforms are also self-referential; they tend to cause new reforms. Thus, reforms can be considered as routines: they are likely to be repeated over and over again.

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