Forest Attributes (forest + attribute)

Distribution by Scientific Domains

Selected Abstracts

Wind speed measurements and forest damage in Canton Zurich (Central Europe) from 1891 to winter 2007

Tilo Usbeck
Abstract The most severe damage to forests in central Europe occurs during winter storms that are caused by Northern Hemispheric mid-latitude cyclones. These winter storms have caused several catastrophic windthrows during the past four decades. Amounts of forest storm damage are believed to be a function of both the size of the forest and the storm intensity. To test this hypothesis, the Zurich region (city and canton) was chosen because long-term climate observation data is available for the region. The relationships between forest attributes, wind speed and forest damage were explored by comparing data on forests and wind speed from 107 winters with forest damage. Storm damage was defined as the proportion of damaged forests with respect to the growing stock. The variables: daily wind run (91 years), daily maximum hourly average wind speed (107 years) and peak gust wind speed (74 years) were homogenized with respect to high wind speed and related to levels of forest damage. High maximum wind speed at the end of the 19th century and at the beginning of the 20th century was followed by low maximum wind speed in the 1940s, 1960s and 1970s. Since then, maximum values have increased. Gusts (extremes of the maximum wind speed) increased from the beginning of the recordings in 1933 and peaked in the early 1990s. Forest damage due to winter storms is best correlated with peak wind speed. Gusts exceeding 40 m/s and resulting in catastrophic windthrow have increased in recent winters. Copyright © 2009 Royal Meteorological Society [source]

Ecological correlates of abundance in the Tana mangabey (Cercocebus galeritus)

Julie Wieczkowski
Abstract I investigated the ecological correlates of abundance in the Tana mangabey (Cercocebus galeritus), one of the world's most endangered primates, with the goal of recommending management strategies. I systematically selected 31 forest fragments throughout the mangabey's 60-km distribution along the lower Tana River in southeastern Kenya. Within the 31 fragments, I measured vegetation structure, food abundance, and human forest product use in 107 belt transects, and conducted 370 mangabey surveys. I used a weighted multiple regression analysis to determine whether there was a dependence between the selected forest attributes and the mean number of mangabey groups per fragment. Fragment area and density of trees ,10 cm diameter at breast height (DBH) were the only variables that significantly correlated with the variation in mangabey abundance. No additional variables were significant when the analysis was limited to forest fragments inside the Tana River Primate National Reserve (TRPNR) or to fragments outside the TRPNR. When I estimated the resources available before recent human forest product use by adding nonharvested and harvested variables, the total basal area of the top 15 food species became significant. This was only within the TRPNR, however. Management, therefore, should focus on increasing forest area, density of trees ,10 cm DBH, and coverage of food trees throughout the mangabey's distribution. Solutions must be found for the problem of forest clearing, and forest product use must be better managed to protect the habitat of this critically endangered primate. The significance of food abundance only within the TRPNR suggests a need to collect dietary data from mangabey groups in fragments toward the southern limit of the mangabey's distribution, where plant species composition differs from that in fragments in which dietary data have been previously collected. Am. J. Primatol. 63:125,138, 2004. © 2004 Wiley-Liss, Inc. [source]

Contributions of ethnobiology to the conservation of tropical rivers and streams

R.A.M. Silvano
Abstract 1.This study aimed to link basic ethnobiological research on local ecological knowledge (LEK) to the conservation of Brazilian streams, based on two case studies: original data on LEK of fishermen about freshwater fish in the Negro River, Amazon, and previously published data about LEK of farmers on the ecological relationship between forest and streams in the Macabuzinho catchment, Atlantic Forest. 2.Information was obtained from fishermen through interviews using standard questionnaires containing open-ended questions. Informants for interview were selected either following some defined criteria or applying the ,snowball' method. 3.Fishermen's LEK about the diets and habitats of 14 fish species in the Negro River provided new biological information on plant species that are eaten by fish, in addition to confirming some ecological patterns from the biological literature, such as dependence of fish on forests as food sources. 4.In the Atlantic Forest, a comparison between farmers' LEK and a rapid stream assessment in the farmers' properties indicated that farmers tended to overestimate the ecological integrity of their streams. Farmers recognized at least 11 forest attributes that correspond to the scientific concept of ecosystem services. Such information may be useful to promote or enhance dialogue among farmers, scientists and managers. 5.These results may contribute to the devising of ecosystem management measures in the Negro River, aimed to conserve both rivers and their associated floodplain forests, involving local fishermen. In the Atlantic Forest, we proposed some initiatives, such as to allow direct economic use of their forests to conciliate conflicting perceptions of farmers about ecological benefits versus economic losses from reforestation. Despite their cultural, environmental and geographical differences, the two study cases are complementary and cost-effective and promising approaches to including LEK in the design of ecological research. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Tana River Mangabey Use of Nonforest Areas: Functional Connectivity in a Fragmented Landscape in Kenya

BIOTROPICA, Issue 5 2010
Julie Wieczkowski
ABSTRACT Habitat loss and fragmentation is a serious threat to biodiversity. Fragment isolation can be reduced if fragments are connected, either structurally through habitat corridors or functionally if the species can move through the surrounding matrix. One-way to evaluate landscape connectivity is to observe natural movements of animals within fragmented landscapes. The Tana River mangabey (Cercocebus galeritus) is an endangered monkey endemic to fragmented forests along the lower Tana River in Kenya, and who has been observed to move through matrix between fragments. One mangabey group moved through 1 km of matrix, while another group moved through two areas of matrix. I collected behavioral and ranging data on the latter group to describe its behavior and time spent in the matrix. Utilizing data from belt transects in the matrix and forest fragments, I characterized the vegetation structure of the matrix and compared it to the forests included in each group's home range. The group spent the majority of their time eating while in the matrix, and spent an average 36.4 min in one matrix area and 100 min in the other. The matrix is generally characterized by the highest measures for a nonforest attribute and the lowest measures for forest attributes. These results suggest that forest fragments are functionally, but not structurally, connected for the mangabey; a landscape approach to conservation, therefore, should be taken for the lower Tana River. Research investigating the limitations of the mangabey's ability to use the matrix is needed. [source]

Recovery of a Subtropical Dry Forest After Abandonment of Different Land Uses,

BIOTROPICA, Issue 3 2006
Sandra Molina Colón
ABSTRACT We studied the ecological characteristics of 45,50-yr-old subtropical dry forest stands in Puerto Rico that were growing on sites that had been deforested and used intensively for up to 128 yr. The study took place in the Guánica Commonwealth Forest. Our objective was to assess the long-term effects of previous land use on this forest,i.e., its species composition, structure, and functioning. Previous land-use types included houses, farmlands, and charcoal pits. Stands with these land uses were compared with a nearby mature forest stand. The speed and path of forest recovery after deforestation and land-use abandonment depended on the conditions of the land. Study areas where land uses had removed the forest canopy and altered soil conditions (houses and farmlands) required a longer time to recover and had a different species composition than study areas where land uses retained a forest canopy (charcoal pits). Different forest attributes recovered at different rates. Crown area index, stem density, and litterfall rate recovered faster than stemwood and root, biomass, tree height, and basal area. Where previous land uses removed the canopy, Leucaena leucocephala, a naturalized alien pioneer species, dominated the regrowth. Native species dominated abandoned charcoal pits and mature forest. The change in species composition, including the invasion of alien species, appears to be the most significant long-term effect of human use and modification of the landscape. RESUMEN Estudiamos las características ecológicas de rodales de un bosque seco subtropical en Puerto Rico que tenían 45-50 años de recuperación después de haber sido usados intensamente durante 128 años. El estudio se realizó en el Bosque Estatal de Guánica. Nuestro objetivo fue el de evaluar los efectos a largo plazo de los distintos tipos de usos del terreno en la composición de especies, la estructura y el funcionamiento. Los usos de terreno en el pasado incluyeron viviendas, terrenos agrícolas y carboneras. Estos rodales fueron comparados con un rodal de bosque maduro en un área cercana. La rápidez de recuperación y la manera en cómo sucede depende de las condiciones del terreno después de ser abandonado. Las áreas de estudio en las que se había removido el dosel y alterado las condiciones del suelo (casas y terrenos agrícolas) necesitaron más tiempo para recuperarse y reflejaron una composición de suelo diferente a las áreas de estudio donde el dosel se mantuvo (carboneras). Los diferentes atributos forestales se recuperaban a ritmos diferentes. El índice del área foliar de la copa, la densidad de tallos y la caída de hojarasca se recuperaron más rápido que la biomasa de tallos y raíces, la altura de los árboles y el área basal. La especie pionera naturalizada, Leucaena leucocephala (Lam.) de Wit-Fabaceae, fue la especie dominante en los bosques donde se habia removido el dosel. Las especies nativas dominaban las carboneras abandonadas y el bosque maduro. El cambio en la composición de especies e incluso la invasión de especies foráneas, parece ser el efecto a largo plazo más significativo del uso humano y de la modificación del paisaje. [source]