Spelling suggestions: "subject:"remnant vegetation"" "subject:"remnants vegetation""
1 |
Ecology of arboreal marsupials in a network of remnant linear habitats.Van der Ree, Rodney, mikewood@deakin.edu.au January 2000 (has links)
Linear strips of vegetation set within a less-hospitable matrix are common features of landscapes throughout the world. Depending on location, form and function, these linear landscape elements include hedgerows, fencerows, shelterbelts, roadside or streamside strips and wildlife corridors. In many anthropogenically-modified landscapes, linear strips are important components for conservation because they provide a large proportion of the remaining wooded or shrubby habitat for fauna. They may also function to provide connectivity across the landscape. In some districts, the linear strips form an interconnected network of habitat.
The spatial configuration of remnant habitat (size, shape and arrangement) may influence habitat suitability, and hence survival, of many species of plant and animal in modified landscapes. Near Euroa in south-eastern Australia, the clearing and fragmentation of temperate woodlands for agriculture has been extensive and, at present, less than 5% tree cover remains, most of which (83%) occurs as linear strips along roads and streams. The remainder of the woodland occurs as relatively small patches and single isolated trees scattered across the landscape. As an assemblage, arboreal marsupials are woodland dependent and vary in their sensitivity to habitat loss and fragmentation.
This thesis focusses on determining the conservation status of arboreal marsupials in the linear network and understanding how they utilise the landscape mosaic. Specifically, the topics examined in this thesis are: (1) the composition of the arboreal marsupial assemblage in linear and non-linear woodland remnants; (2) the status and habitat preferences of species of arboreal marsupial within linear remnants; and (3) the ecology of a population of the Squirrel Glider Petaurus norfolcensis in the linear network, focusing on population dynamics, spatial organisation, and use of den trees.
The arboreal marsupial fauna in the linear network was diverse, and comprised seven out of eight species known to occur in the district. The species detected within the strips were P. norfolcensis, the Sugar Glider Petaurus breviceps, Common Brushtail Possum Trichosums vulpecula, Common Ringtail Possum Pseudocheirus peregrinus, Brush-tailed Phascogale Phascogale tapoatafa, Koala Phascolarctos cinereus and Yellow-footed Antechinus Antechinus flavipes. The species not detected was the Feathertail Glider Acrabates pygmaeus. Survey sites in linear remnants (strips of woodland along roads and streams) supported a similar richness and density of arboreal mammals to sites in non-linear remnants (large patches or continuous tracts of woodland nearby). Furthermore, the combined abundance of all species of arboreal marsupials was significantly greater in sites in the linear remnants than in the non-linear remnants. This initial phase of the study provided no evidence that linear woodland remnants support a degraded or impoverished arboreal marsupial fauna in comparison with the nonlinear remnants surveyed.
Intensive trapping of arboreal marsupials within a 15 km linear network between February 1997 and June 1998 showed that all species of arboreal marsupial (except A. pygmaeus) were present within the linear strips. Further analyses related trap-based abundance estimates to measures of habitat quality and landscape structure. Width of the linear habitat was significantly positively correlated with the combined abundance of all arboreal marsupials, as well as with the abundance of P. norfolcensis and T. vulpecula. The abundance of T. vulpecula was also significantly positively correlated with variation in overstorey species composition, Acacia density and the number of hollow-bearing trees. The abundance of P. norfolcensis was positively correlated with Acacia density and canopy width, and negatively correlated with distance to the nearest intersection with another linear remnant. No significant variables were identified to explain the abundance of P. tapoatafa, and there were insufficient captures of the remaining species to investigate habitat preferences.
Petaurus norfolcensis were resident within the linear network and their density (0.95 -1.54 ha-1) was equal to the maximum densities recorded for this species in continuous forest elsewhere in south-eastern Australia. Rates of reproduction were also similar to those in continuous forest, with births occurring between May and December, a mean natality rate of 1.9, and a mean litter size of 1.7. Sex ratios
never differed significantly from parity. Overall, the population dynamics of P. norfolcensis were comparable with published results for the species in contiguous forest, clearly suggesting that the linear remnants currently support a self-sustaining, viable population.
Fifty-one P. norfolcensis were fitted with radio transmitters and tracked intermittently between December 1997 and November 1998. Home ranges were small (1.3 - 2.8 ha), narrow (20 - 40 m) and elongated (322 - 839 m). Home ranges were mostly confined to the linear remnants, although 80% of gliders also utilised small clumps of adjacent woodland within farm paddocks for foraging or denning. Home range size was significantly larger at intersections between two or more linear remnants than within straight sections of linear remnants. Intersections appeared to be important sites for social interaction because the overlap of home ranges of members of adjacent social groups was significantly greater at intersections than straight sections. Intersections provided the only opportunity for members of three or more social groups to interact, while still maintaining their territories.
The 51 gliders were radiotracked to 143 different hollow-bearing trees on 2081 occasions. On average, gliders used 5.3 den trees during the study (range 1-15), and changed den trees every 4.9 days. The number of den trees used by each glider is likely to be conservative because the cumulative number of den trees continued to increase over the full duration of the study. When gliders shifted between den trees, the mean distance between consecutive den sites was 247 m. Den trees were located throughout a glider's home range, thereby reducing the need to return to a central den site and potentially minimising energy expenditure. Dens were usually located in large trees (mean diameter 88.5 cm) and were selected significantly more often than expected based on their occurrence within the landscape.
The overall conclusion of this thesis is that the linear network I studied provides high quality habitat for resident populations of arboreal marsupials. Important factors influencing the suitability of the linear remnants appear to be the high level of network connectivity, the location on soils of high nutrient status, the high density of large trees and an acacia understorey. In highly fragmented landscapes, linear habitats as part of the remaining woodland mosaic have the potential to be an integral component in the conservation of woodland-dependent fauna. The habitat value of linear strips of vegetation should not be underestimated.
|
2 |
Fragmentation effects on fitness in five common prairie species /Miramontes Loyd, Lydia, January 2009 (has links) (PDF)
Thesis (M.S.)--Eastern Illinois University, 2009. / Includes bibliographical references (leaves 29-35).
|
3 |
Occurrence and reproductive role of remnant old-growth trees in mature Douglas-fir forests, southern Washington, Cascade Range /Keeton, William Scott. January 2000 (has links)
Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 107-124).
|
4 |
Ground dwelling beetle assemblages of remnant and created prairies of east-central IndianaBrown, Angela M. January 2004 (has links)
Prairie restorations in east-central Indiana are commonly accomplished through purposeful planting of prairie vegetation, with the belief that prairie fauna will populate the planting independently at a later time. The objective of this study was to determine whether one assemblage, the ground dwelling beetles, would in fact re-populate tallgrass prairie restorations in a region where tallgrass prairie remnants are rare and highly fragmented. Two prairie remnants and five prairie plantings were sampled using pitfall traps from 21 May to 4 October 2003. Nine hundred forty-three beetles were collected, identified to family, and separated into morphospecies. Shannon diversity was greatest in the CR 575 E Cemetery prairie remnant, and increased linearly with increasing age in the created prairies, with the exception of the 1-year old prairie. TWINSPAN analysis grouped the two remnant prairies together in the first division, indicating that beetle assemblages of remnant prairies are more similar to each other than to created prairies. / Department of Biology
|
5 |
Limitations to plant root growth in highly saline and alkaline bauxite residueKopittke, P. M. Unknown Date (has links)
No description available.
|
6 |
Nature Conservation in Indonesia in the 21st Century: Can decentralisation work?Gunarso, P. Unknown Date (has links)
No description available.
|
7 |
Modeling unplanned landscape change: A Colombian case studyEtter, A. Unknown Date (has links)
No description available.
|
8 |
Modeling unplanned landscape change: A Colombian case studyEtter, A. Unknown Date (has links)
No description available.
|
9 |
Beyond fragmentation : lizard distribution patterns in two production landscapes and their implications for conceptual landscape models /Fischer, Joern. January 2004 (has links)
Thesis (Ph.D.)--Australian National University, 2004.
|
10 |
Aspects of community ecology, population growth and genetic structure applied to the conservation of Polemonium pectinatum (Polemoniaceae), a rare and threatened shrub-steppe perennial /Gilbert, Cynthia. January 1998 (has links)
Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographic references (leaves [114]-129).
|
Page generated in 0.1046 seconds