Home About us Contact
|
Home About us Contact | ||
|
|
||
Logged Forest (logged + forest)
Selected AbstractsThe spatial pattern of soil-dwelling termites in primary and logged forest in Sabah, MalaysiaECOLOGICAL ENTOMOLOGY, Issue 1 2007SARAH E. DONOVAN Abstract 1.,Primary and logged lowland dipterocarp forest sites were sampled for subterranean termites using soil pits located on a grid system in order to detect any patchiness in their distribution. 2.,A spatial pattern in termite distributions was observed in the primary and logged sites, but the response differed between soil-feeding and non-soil-feeding termites. 3.,Spatial analysis showed that soil-feeding termites were homogeneously distributed in the primary forest but significantly aggregated in the logged forest. This pattern was reversed for non-soil-feeding termites and may result from differences in resource provisioning between the two sites. 4.,Gaps in termite distribution comprised a greater area than patches for both feeding groups and sites, but gaps dominated the logged site. 5.,A significant association between soil-feeding and non-soil-feeding termite distributions occurred at both sites. This arose from an association between patches in the primary forest and between gaps in the logged forest. 6.,Termite spatial pattern was optimally observed at a minimum extent of 64 m and lag of 2 m. 7.,The spatially explicit SADIE (Spatial Analysis by Distances IndicEs) analyses were more successful than (non-spatially explicit) multivariate analysis (Canonical Correspondence Analysis) at detecting associations between termite spatial distributions and that of other biotic and abiotic variables. [source] Testing liana cutting and controlled burning as silvicultural treatments for a logged forest in the eastern AmazonJOURNAL OF APPLIED ECOLOGY, Issue 6 2001Jeffrey J. Gerwing Summary 1In the eastern Brazilian Amazon, logged forests frequently include patches where liana density is particularly high. In these so-called liana tangles, competition from lianas is predicted to reduce tree growth significantly, thus effectively impeding future timber production. To begin to develop a silvicultural strategy for these patches, the impact of liana cutting and controlled burning on liana density, tree growth and tree regeneration in liana-dominated patches was investigated in a logged forest in the eastern Brazilian Amazon. 2The two treatments (liana cutting and controlled burning) and a control were installed in 40 × 40-m plots in a randomized complete block design of six blocks. Treatments were conducted during October 1997, and tree diameter growth and mortality, canopy cover, regeneration and liana density were monitored over 2 years. 3Mean mortality following burning was significantly higher for lianas (79%) than for trees (48%), as was the mean coppicing rate of top-killed stems (42% for lianas vs. 20% for trees). Coppicing combined with some recruitment from seed resulted in liana densities in the burned plots returning to 70% of the values in the control plots only 2 years post-treatment. 4Canopy light transmittance, estimated from hemispherical canopy photographs taken at 1 m above the ground, increased significantly from c. 4% in controls to 8% in cut and 12% in burned treatments, and these differences persisted over the 2-year study period. 5In the absence of silvicultural intervention, mean tree diameter increments were low (1·3 mm year,1), suggesting that the successional transition to higher stature forest was occurring very slowly. Each of the treatments resulted in a more than doubling of mean annual tree growth (3 and 2·8 mm year,1 for liana-cut and burned treatments, respectively). The treatments also significantly reduced the occurrence of trees that showed no growth over the study period, from 56% in controls to 30% in cut and 32% in burned treatments. 6The results of this study suggest that although burning resulted in increased tree growth, rapid recolonization of surviving trees by lianas and the high vulnerability of burned stands to unwanted repeat burns are likely to cancel out any of the possible benefits of controlled burning as a silvicultural treatment for liana-dominated patches. Liana cutting, on the other hand, showed promise and its adoption as part of a larger strategy for the recuperation of the timber production potential of logged tropical forests seems warranted. [source] Home ranges and survival of Nahan's Francolin Francolinus nahani in Budongo Forest, UgandaAFRICAN JOURNAL OF ECOLOGY, Issue 4 2009Eric Sande Abstract We studied home ranges, habitat use and survival of radio-tagged Nahan's Francolin in Budongo Forest Reserve, Uganda during July 1998,December 1999. We studied Nahan's Francolin in an unlogged nature reserve, in a compartment logged in 1947,1952 and in a compartment logged twice, in 1963,1964 and 1996,1997. Mean home range was 14.22 ± 1.35 ha (n = 17). The home range was significantly larger in the nature reserve than in the recently logged compartment. Birds spent more time during the day in areas with high understorey vegetation density but preferred to roost and nest between buttresses of large trees. Understorey vegetation density and canopy openness were significantly greater in the logged forest than in the nature reserve. Annual survival of adult Nahan's Francolins was 20.09 ± 7.33% (n = 23). Our results suggest that the maintenance of large trees and areas with high understorey vegetation density are both important for Nahan's Francolin. Résumé Nous avons étudié le territoire, l'utilisation de l'habitat et la survie de francolins de Nahan marqués dans la Réserve Forestière de Budongo, en Ouganda, entre juillet 1998 et décembre 1999. Nous avons étudié les francolins de Nahan dans une réserve naturelle non exploitée, dans une parcelle qui avait été exploitée entre 1947 et 1952 et dans une parcelle où des coupes de bois avaient eu lieu deux fois, en 1963,64 et en 1996,97. Le territoire moyen couvrait 14,22 ± 1,35 ha (n = 17). Le territoire était significativement plus grand dans la réserve naturelle que dans la parcelle récemment exploitée. Pendant la journée, les oiseaux passaient plus de temps dans les endroits où la végétation des sous-bois était très dense, mais ils préféraient se percher et nicher protégés par le rempart de grands arbres. La densité de la végétation des sous-bois et l'ouverture de la canopée étaient sensiblement plus grandes dans la forêt exploitée que dans la réserve naturelle. La survie annuelle des francolins adultes était de 20.09 ± 7.33% (n = 23). Nos résultats suggèrent que le maintien de grands arbres et de zones où la végétation des sous-bois est dense est très important pour le francolin de Nahan. [source] Effects of selective logging on tree diversity, composition and plant functional type patterns in a Bornean rain forestJOURNAL OF VEGETATION SCIENCE, Issue 1 2003René Verburg Sidiyasa et al. (1999); Anon. (1955,1994) Abstract. The effects of selective logging on tree diversity, changes in tree species composition and plant functional types were studied with the use of seven permanent plots in virgin and in logged forest. All plots were located in a lowland dipterocarp rain forest in East Kalimantan on the island of Borneo. Just after logging and during the following 20 yr tree diversity measured as Fishers', was not significantly affected in logged forest plots. Temporal shifts in tree species composition were analysed with Principal Component Analysis (PCA). Logged forest plots had much larger changes over time than virgin forest plots. In the smallest diameter class, some logged forest plots showed a distinct trajectory in PCA space compared to virgin forest plots, while in larger diameter classes movement of logged plots in PCA space was random. This suggests that there is no predetermined community to which logged forest plots tend to shift when recovering from logging. We found a significant negative correlation between diameter increments and the species-specific wood densities of tree species. Species-specific wood density and potential tree height were used to assign species to five PFTs. As expected, logging increased the fraction of softwood stems in small diameter classes. In the largest diameter classes (, 50 cm DBH) a strong decrease of softwood emergent stems was found in logged forest plots. After more than 20 yr no recruitment was found of softwood emergent stems in selectively logged forest. [source] Movement trajectories and habitat partitioning of small mammals in logged and unlogged rain forests on BorneoJOURNAL OF ANIMAL ECOLOGY, Issue 5 2006KONSTANS WELLS Summary 1Non-volant animals in tropical rain forests differ in their ability to exploit the habitat above the forest floor and also in their response to habitat variability. It is predicted that specific movement trajectories are determined both by intrinsic factors such as ecological specialization, morphology and body size and by structural features of the surrounding habitat such as undergrowth and availability of supportive structures. 2We applied spool-and-line tracking in order to describe movement trajectories and habitat segregation of eight species of small mammals from an assemblage of Muridae, Tupaiidae and Sciuridae in the rain forest of Borneo where we followed a total of 13 525 m path. We also analysed specific changes in the movement patterns of the small mammals in relation to habitat stratification between logged and unlogged forests. Variables related to climbing activity of the tracked species as well as the supportive structures of the vegetation and undergrowth density were measured along their tracks. 3Movement patterns of the small mammals differed significantly between species. Most similarities were found in congeneric species that converged strongly in body size and morphology. All species were affected in their movement patterns by the altered forest structure in logged forests with most differences found in Leopoldamys sabanus. However, the large proportions of short step lengths found in all species for both forest types and similar path tortuosity suggest that the main movement strategies of the small mammals were not influenced by logging but comprised generally a response to the heterogeneous habitat as opposed to random movement strategies predicted for homogeneous environments. 4Overall shifts in microhabitat use showed no coherent trend among species. Multivariate (principal component) analysis revealed contrasting trends for convergent species, in particular for Maxomys rajah and M. surifer as well as for Tupaia longipes and T. tana, suggesting that each species was uniquely affected in its movement trajectories by a multiple set of environmental and intrinsic features. [source] Responses of ants to selective logging of a central Amazonian forestJOURNAL OF APPLIED ECOLOGY, Issue 3 2000H.L. Vasconcelos Summary 1.,Relatively little information exists on the effects of logging on rain forest organisms, particularly in the Neotropics where logging operations have increased dramatically in recent years. In this study we determined experimentally the effects of selective logging of a central Amazonian forest on ground-living ants. 2.,The experimental design consisted of three 4-ha replicated plots representing control unlogged forest, forest logged 10 years prior to the start of the study (1987), and forest logged 4 years prior to the start of the study (1993). The logging operation removed 50% of the basal area of trees of commercial value, or about eight trees per hectare. This resulted in a significant decrease in canopy cover, and an increase in understorey vegetation density in logged plots relative to controls. 3.,Collection and identification of ants from a total of 360 1-m2 samples of leaf-litter revealed 143 ant species, of which 97 were found in the control plots, 97 in the plots logged in 1987, and 106 in those logged in 1993. Species richness, evenness and mean abundance (ants m,2) per plot did not vary among treatments. Most of the species found in the control plots were also present in the logged plots. However, population density of many species changed as a result of logging, an effect that persisted for at least 10 years after logging. Species commonly found in sites that were directly disturbed by logging (gaps and tracks) were rare in the undisturbed forest, as revealed by an additional collection of ants. 4.,These results suggest that the persistence of ant assemblages typical of undisturbed forest is likely to depend on the amount of structural damage incurred by logging. Thus management techniques that minimize logging impacts on forest structure are likely to help maintain the conservation value of logged forests for ground-dwelling ants. It is particularly important to minimize the extent of logging roads and tracks created by heavy machinery because these areas appear more prone to invasion by non-forest species. [source] | ||||||||||