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Response of Exotic Invasive Plant Species To Forest Damage Caused By Hurricane Isabel
BRB
Available Online

Boucher, D.H.

,

Kyde, K.I.

,

Snitzer, J.L.

2005
In September 2003, Hurricane Isabel caused unexpectedly high levels of wind damage to an 80-to 100-year-old forest in the Piedmont of Maryland. The storm had decreased in intensity from landfall by the time it reached the study site—sustained winds were moderate and maximum gusts recorded in the area were only 62.7 mph (28.1 m?s-1). Midsized gaps (up to 1 ha) were created in forest that historically had only small or single-tree gaps. Isabel created the opportunity to determine whether natural disturbance facilitates the spread of exotic invasive plant species. Exotic invasive species populations were sampled in 400 5 x 5 m quadrats in a heavily damaged 1-ha, long-term forest study plot and in 160 5 x 5 m quadrats in 0.4 ha of a nearby, less-damaged forest between mid-October and mid-December 2003. Light levels (quantum flux density of photosynthetically active radiation) in the heavily disturbed Permanent Plot and the Less Damaged control plot were surveyed in October 2003 and 2004. The fall 2004 resurvey for exotic plants has also been completed. Based on a random sample of the fall 2004 exotics data, exotic invasive plant species responded strongly to the increased light levels in patches of forest damaged by Isabel. Collectively, the mean increase in percentage cover of exotic plants was 47.8% in high-light canopy gaps versus only 4.8 % in low-light non-gaps and 4.2% in the less-damaged forest. Several individual exotic species—Polygonum perfoliatum, Polygonum positive responses to higher light levels. The shadeloving caespitosum, and Lonicera japonica had significant biennial, Alliaria petiolata, changed significantly in the opposite direction, decreasing in the high-light areas and increasing in the lowlight areas. The authors are also investigating the interaction of exotic plants with native plants, forest regeneration, and white-tailed deer (Odocoileus virginianus) in damaged areas. Study areas and exclosures for these projects were set up in 2004 and will be resurveyed beginning in 2005.
The impact of Hurricane Frances (2004) on the invasive Australian pine (Casuarina equisetifolia L.) on San Salvador Island, the Bahamas
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Gamble, Douglas W.

,

Rodgers, John C.

2008
On September 2, 2004 Hurricane Frances (Category 3) passed directly over San Salvador Island, The Bahamas. This event offered the opportunity to gather baseline data regarding the impact of hurricanes on populations of the invasive Australian pine (Casuarina equisettifolia L.) in the Bahamas. Results of vegetation surveys within both forest stands and beach environments suggest that the overall impact of this hurricane was minimal. Less than 13% of forest individuals and 17% of beach individuals surveyed were damaged, and the majority of damage was restricted to just one location for both the forest and beach study sites. The most common damage type within the forest sites was “snapped” trees (8%) and this primarily occurred within trees ranging in size from 7–12 cm in diameter. Browning of the entire foliage was the most common damage type within the beach sites (9.3%) but this damage type only occurred within tree sizes less than or equal to 90 cm in height. Thus it appears that Hurricane Frances had a negligible effect on Australian pine populations as a whole on San Salvador Island and that this disturbance event will probably not limit future population expansion. It is suggested that more powerful or more frequent hurricanes would be needed to significantly affect Australian pine populations on San Salvador Island. Similar patterns in damage should be expected with comparable hurricane events on other islands in the Bahamas and for other tropical beaches in which this species has invaded.
Seaweeds of American Samoa
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Posa A. Skelton

This study provides the latest, up-to-date information on the diversity of marine plants (algae and seagrasses) of American Samoa. A general introduction to marine plants is provided, with observations on the flora of the islands. An illustrated guide to 67 macroalgae and seagrasses is provided in this report. The surveys covered 26 sites from four inhabited islands Tutuila, Aunu’u, Ofu and Olosega and two smaller uninhabited islands – Nu’utele and Nu’usilaelae. The habitats surveyed include subtidal sites to 20-m depth, inter tidal and the spray or splash zone. It also included surveys of relatively pristine coral reefs as well as high impact areas such as the inner Pago Pago Harbor. Two separate surveys, both over a two-week period in October 2002 and September 2003 were carried out and the final results are reported herein. A total of 635 specimens were analyzed and 239 algal and seagrass species were enumerated. The red algae (Rhodophyta) had the highest number of species with 133 identified. The green algae (Chlorophyta) had 60 species, the brown algae (Phaeophyta) had 29, and the blue-green (Cyanophyta) 27; only two seagrass species were found. This study showed that the flora of American Samoa is diverse, and that what is recorded reflects about 60% of the potential flora. The most diverse site was Utulei with 56 species; a site located near the Pago Pago Harbor entrance. Other notable diverse sites include the Fagatele National Marine Sanctuary with 50 species, Fagasa (44), Mafafa (36), Aua (32), and Onososopo and Fagaalu both with 31 species. The least diverse sites were the docks and the smaller Nu’usilaelae Island. This is attributed to the limited collections from these sites for safety reasons. There are no substantiated records of endemic algae or seagrasses from American Samoa. Two species recorded by the American phycologist, William Setchell in 1924 (Sargassum fonanonense and Sargassum anapense) need more studies to verify their endemicity, as similar species have been recorded in the neighboring Western Samoa islands, where they are known under different names. Four algae are considered to be recently introduced into the American Samoan flora. Halymenia durvillei and Caulerpa serrulata may have been introduced from Apia Harbor, Western Samoa, whereas Grateloupia filicina and Codium mamillosum may have been introduced from places beyond the Archipelago. Although only single specimens were collected for the latter two algae, it is prudent that monitoring and surveys must be maintained to keep abreast of any potential impacts. The flora of American Samoa fits in with the biogeographic theory of decreasing diversity away from the Indo-Pacific centre of biodiversity. The 222 species of red, green and brown algae is well above those of the Cook Islands (67) and the Easter Islands (134), but below that of French Polynesia (308). The reason for this disparity is attributed to the intensity of collections. The diversity of American Samoan seagrasses and algae are better known than those of neighboring island countries. To allow for a continuous buildup and maintenance of this knowledge the following observations and recommendations are made.
Forests, trees and food
BRB
Available Online
1992
Despite substantial increases in food production in many countries over the past two decades, the world is still poorly fed. Over 500 million people suffer from malnutrition; and every year about 20 million people die of starvation and its related diseases. In this situation, it is important that every effort be made to improve nutrition and increase food security, particularly for the rural poor. This publication aims to afford proper recognition to the contribution forests and trees make to the food economies of rural societies. It also outlines the changes that need to be made within forestry institutions to enable them to make a significant contribution to the food security of local communities. Food security is increased not only by the presence of forests but also by the small stands of trees found in homegardens and on farms. We use the term `cultivated trees' to describe the latter, and reserve the term `forests' for large stands of trees situated outside the homestead or farm, whether such forests are managed or not. Both play major, often little recognized roles in improving food security in rural communities. Parts of forest plants and trees are also used in traditional medicines. These medicines stimulate appetite, help the body to utilize nutrients in food, and fight infection. Tree products provide an extra source of income for the rural poor without which many families would go hungry or become malnourished. Fuelwood and charcoal, rattan and other materials for furniture making, tendu leaves for cigarette manufacture, gum arabic for a variety of industrial uses, numerous oils and resins, dyes and medicines are all sold by the rural poor. They enable millions of the poorest people in the world to earn the cash they need to avoid starvation. Forests and agroforestry systems also play important roles in stabilizing agriculture's resource base, for example, by slowing down soil erosion by wind and water and reducing sedimentation in rivers. In some cases, trees improve and enrich agricultural soil and help stabilize water supplies, thus improving soil productivity and making sustainable cultivation of marginal lands possible. Trees also exert important influences on micro-climates, thereby improving agricultural production.