The Experts below are selected from a list of 174 Experts worldwide ranked by ideXlab platform
Carl D. Grant - One of the best experts on this subject based on the ideXlab platform.
-
fire and silvicultural management of restored Bauxite Mines in western australia
Restoration Ecology, 2007Co-Authors: Carl D. Grant, Melanie A. Norman, Martin A SmithAbstract:To be self-sustaining in the longer-term and meet defined completion criteria, it is important that the management of restored Bauxite Mines can be integrated with the surrounding unmined Jarrah (Eucalyptus marginata) forest. A number of research projects relating to fire management have been undertaken in restored areas over the past 15 years. The broad objectives of these studies have been to assess the resilience of different-aged restored sites to fire and define the most suitable fire regime (season, intensity, and frequency) to utilize in the management of these areas. Restored areas were found to be a low fire risk up to five years of age because litter fuel was discontinuous and could not normally carry the fire. Between the ages of five and 12-15 years, restored areas were very susceptible to fire due to high fuel loads and a prominent midstory of senescent legume species. However, if burnt at this age, restoration areas were extremely resilient. Restored areas that are older than 12-15 years can be integrated with prescribed burning of the surrounding unmined forest because the midstory layer has collapsed and the overstory is now separated from the understory fuel. The most suitable fire regime to utilize in restored areas is low- to moderate-intensity spring burns. Silvicultural management of restored areas has recently been investigated incorporating noncommercial thinning and commercial harvesting operations in association with prescribed burning. Restored areas of suitable ages appear to be able to be integrated with the management regimes commonly used in the Jarrah forest.
-
vertebrate fauna recolonization of restored Bauxite Mines key findings from almost 30 years of monitoring and research
Restoration Ecology, 2007Co-Authors: Owen G Nichols, Carl D. GrantAbstract:Studies into the processes of vertebrate fauna colonization of Alcoa's restored Bauxite Mines began around 1975. This recognized the key role of vertebrate fauna in jarrah forest ecosystem processes, and also the fact that some species were rare, so priority was given to determining their status in unmined forest, and promoting their return to restored areas following mining. Long-term studies have since taken place on mammals, birds, and reptiles both in unmined forest and in restored areas of varying ages and techniques. Mammal recolonization varies between species depending on species' food and shelter requirements and their distribution and abundance in the surrounding forest. Birds rapidly recolonize and 95% of species have been recorded in restoration. Bird community structure changes with restoration type and age, and in current restoration, it is similar to that of unmined forest by the age of 10 years. Studies on reptiles have shown that 21 of 24 species have recolonized. The remaining three include one legless lizard and two snakes, all of which feed on small vertebrates (e.g., skinks) and require shelter in the form of logs, stumps, and coarse woody debris. Some other reptile species consistently occur in restoration in lower densities than in unmined forest, and current studies are investigating the causes of this. Together, studies on these three vertebrate fauna groups have provided valuable, complementary information on their habitat requirements, and the extent to which Alcoa's restoration program has been successful in reestablishing this important component of the jarrah forest's biodiversity.
-
Vertebrate Fauna Recolonization of Restored Bauxite Mines—Key Findings from Almost 30 Years of Monitoring and Research
Restoration Ecology, 2007Co-Authors: Owen G Nichols, Carl D. GrantAbstract:Studies into the processes of vertebrate fauna colonization of Alcoa's restored Bauxite Mines began around 1975. This recognized the key role of vertebrate fauna in jarrah forest ecosystem processes, and also the fact that some species were rare, so priority was given to determining their status in unmined forest, and promoting their return to restored areas following mining. Long-term studies have since taken place on mammals, birds, and reptiles both in unmined forest and in restored areas of varying ages and techniques. Mammal recolonization varies between species depending on species' food and shelter requirements and their distribution and abundance in the surrounding forest. Birds rapidly recolonize and 95% of species have been recorded in restoration. Bird community structure changes with restoration type and age, and in current restoration, it is similar to that of unmined forest by the age of 10 years. Studies on reptiles have shown that 21 of 24 species have recolonized. The remaining three include one legless lizard and two snakes, all of which feed on small vertebrates (e.g., skinks) and require shelter in the form of logs, stumps, and coarse woody debris. Some other reptile species consistently occur in restoration in lower densities than in unmined forest, and current studies are investigating the causes of this. Together, studies on these three vertebrate fauna groups have provided valuable, complementary information on their habitat requirements, and the extent to which Alcoa's restoration program has been successful in reestablishing this important component of the jarrah forest's biodiversity.
-
return of ecosystem function to restored Bauxite Mines in western australia
Restoration Ecology, 2007Co-Authors: Carl D. Grant, Samuel C. Ward, Samantha C MorleyAbstract:A critical aspect of reestablishing a self-sustaining Jarrah (Eucalyptus marginata) forest ecosystem to Bauxite-mined areas is to ensure that vital ecosystem functions such as litter decomposition and nutrient cycling are returned. Significant research has been undertaken over the past 20 years relating to litter decomposition and nutrient cycling. Studies have shown that litter accumulates rapidly in restored areas (1–4 ton ha−1 yr−1) and the accumulated litter tends to be richer in nitrogen due to intentionally elevated densities of nitrogen-fixing species. This leads to a lower (carbon:nitrogen) C:N ratio (60:1 compared to 130:1 in unmined forest) that may promote mineralization of organic N to inorganic forms in restored areas. The major nutrient store in the unmined forest is in the soil and returning soil during the restoration process largely conserves this resource, particularly in relation to P. Short-term plant macronutrient requirements for growth are readily restored by fertilizer application. Studies on the reaccumulation of nutrient pools in the successional development of restored areas have shown that pools equivalent to the unmined forest are established within 10–20 years. Ongoing research is focusing on the rates of cycling processes in burnt and unburnt restored areas, and comparing these to the unmined forest to ensure that key functions have been reestablished. To date, all measured ecosystem function parameters are indicating that restored areas have achieved or are on a trajectory toward a self-sustaining Jarrah forest ecosystem.
-
how does the quantity of course woody debris influence fauna return to restored Bauxite Mines
International Conference on Multimedia Information Networking and Security, 2007Co-Authors: Andrew H Grigg, Carl D. Grant, Richard J Hobbs, Michael D Craig, Mark J Garkaklis, Patricia A Fleming, G E St J HardyAbstract:The value to fauna of dead fallen wood or coarse woody debris (CWD) in Australian forest ecosystems is well established. Reptiles use logs for shelter, to lay eggs and as basking sites, while mammals may use logs for shelter or for nesting (Bell 2004, Grove and Meggs 2003, Lindenmayer et al. 2002). Mac Nally (2006) has also demonstrated the reliance on CWD of certain bird species. Consideration of CWD is therefore important for forest restoration. However, there is only limited information to guide decisions on the quality, condition or configuration of CWD in practical habitat reconstruction activities (Mac Nally et al. 2001). The aim of this study is to determine the response of selected faunal groups to varying quantities of CWD, routinely returned as piles of logs (Brennan et al. 2005), in the restoration of a jarrah forest ecosystem following Bauxite mining in the south-west Western Australia. In particular, do increasing densities of log piles in Mines sites simply provide more habitat, or do the shorter distances between log pile habitats resulting from higher densitities facilitate animal movement (Lindenmayer et al. 2002) and therefore the rate of recolonisation.
John M. Koch - One of the best experts on this subject based on the ideXlab platform.
-
effectiveness of plant guards in reducing grazing of tetraria capillaris in restored Bauxite Mines in western australia
South African Journal of Botany, 2013Co-Authors: Emily M Stantonclements, John M. Koch, Matthew I DawsAbstract:Abstract Herbivores can exert significant impacts on vegetation composition, particularly in open, newly established restored sites where plants are visible and often represent high quality forage. While tree species can potentially outgrow herbivores, understorey plants are unable to do so and may remain prone to herbivory in developing restored sites. We assessed the effectiveness of various mechanical and biological guards ( Acacia companion plants) against grazing of the palatable dryland sedge Tetraria capillaris (hair sedge), in sites restored after Bauxite mining in the jarrah forest of Western Australia. Six months after planting, grazing was severe and repetitive, and affected plant survival. Grazing intensity and severity reduced over time (from 95% to 64% of surviving plants grazed after six and a half years). No method of guarding entirely prevented grazing. Plants with plastic sleeves and Polynet mesh tubes showed significantly higher survival rates in short and longer term compared with unprotected controls (62% survival for both treatments compared with 30% survival of controls after six and a half years). Plastic sleeves were most effective at guarding T.capillaris against grazing although they were less cost-effective than Polynet tubes. While companion planting also reduced grazing it was less effective than artificial guards and not cost-effective. These data indicate that plant guards can have a positive impact on plant performance, even 6.5 years after planting.
-
arthropods in coarse woody debris in jarrah forest and rehabilitated Bauxite Mines in western australia
Annals of Forest Science, 2010Co-Authors: John M. Koch, Andrew H Grigg, Ross K Gordon, Jonathan MajerAbstract:• Coarse woody debris (CWD) is returned to Alcoa’s rehabilitated mined areas in the jarrah forest as potential vertebrate fauna habitat, however, its value for invertebrate fauna has not been investigated. We sought to determine if CWD in rehabilitated areas supported a similar arthropod fauna to that on fallen logs in the adjacent unmined jarrah forest. • Using emergence tents, sampling from logs in 5-year old and 15-year old rehabilitated forest, and in unmined forest, yielded 2266 specimens from 187 taxa. Collembola (43% of total) and Acarina (32%) were the most abundant groups, followed by Diptera (11%), Araneae (4%) and Coleoptera (3%). • There were no significant differences in either taxa richness or overall abundance among the three forest types. However, community composition varied significantly. Species richness from the Araneida, Coleoptera and Diptera was highest in the 5-year old rehabilitated forest, while Collembola and Acarina were better represented in the unmined forest; this was related to changes in the environment surrounding the logs as rehabilitated forest develops, and to log condition. The composition of arthropods on logs in the 15-year old rehabilitated forest was intermediate, indicating a trend of increasing similarity to the unmined forest in arthropod fauna as the rehabilitated forest ages. • We suggest that over longer time periods, CWD in rehabilitated forest will support arthropod communities similar to those found in unmined forest. Future work should determine if returning logs to mined areas facilitates the return of CWD-dependent taxa.
-
Vegetation succession after Bauxite mining in western Australia
Restoration Ecology, 2006Co-Authors: Melanie A. Norman, John M. Koch, Carl D. Grant, Tim K. Morald, Samuel C. WardAbstract:Alcoa World Alumina Australia has been rehabilitating Bauxite Mines in the jarrah forest of Western Australia for more than 35 years. An experiment was established in 1988 using three different seed treatments (legume and small understorey mix, small understorey mix only, and no seed) and two fertilizer treatments (N and P, and P only). The objectives of this study were to (1) document vegetation changes in the first 14 years after Bauxite mining; (2) assess whether the vegetation is becoming more similar to the unmined forest; and (3) gain a better understanding of successional processes. Seed treatments significantly affected 13 of the 14 measured vegetation characteristics. Native species richness was higher in seeded than in unseeded sites at 1, 2, and 5 years of age, whereas diversity and evenness were generally higher at all assessment ages. Exotic species density was higher in unseeded than in seeded sites from 5 years onward, whereas richness was higher from 8 years onward. Nitrogen fertilizer significantly increased exotic species richness, density, and cover. Ephemerals dominated plant density in all rehabilitation treatments over time, whereas seeder species dominated cover. In contrast, resprouting species dominated density and cover in the unmined forest. Orchids were the only species that were not present in the first year in rehabilitated sites but increased in abundance over time. Vegetation composition in rehabilitated areas did not become more similar to the unmined forest during the 14 years since seeding, instead strongly reflected the initial species mix. Rehabilitated Bauxite Mines appear to follow the initial floristic composition model of succession.
-
thirteen year growth of jarrah eucalyptus marginata on rehabilitated Bauxite Mines in south western australia
Australian Forestry, 2005Co-Authors: John M. Koch, S C WardAbstract:Summary Alcoa's objective is to restore its Bauxite Mines in south-western Australia to a productive self-sustaining jarrah forest. This paper describes the growth and form of 13-y-old jarrah (Eucalyptus marginata) trees established from seed and planted seedlings, and subject to various fertiliser, understorey seed and spacing treatments. Seeded jarrah had a mean establishment density of 2662 stems ha−1 and a density of 2300 stems ha−1 after 13 y, a survival rate of 86%. Sixty-two per cent of the seeded trees developed into saplings (> 1.5 m tall). The saplings had a mean height of 9.0 m and dbhob of 14.4 cm after 13 y. The mean density of potential sawlogs (trees with a single stem to at least 2 m) was 1297 stems ha−1 after 13 y. The presence of tall native legumes (acacias) decreased the percentage of trees that became saplings from 72% to 53%. When N fertiliser was not provided the legumes had a suppressive effect on the basal area and bole volume of potential sawlogs, reducing them to 60% and 57%, re...
-
grazing by kangaroos limits the establishment of the grass trees xanthorrhoea gracilis and x preissii in restored Bauxite Mines in eucalypt forest of southwestern australia
Restoration Ecology, 2004Co-Authors: John M. Koch, Jennifer Richardson, Byron B LamontAbstract:This study examined factors affecting germination, survival, and growth of the grass trees Xanthorrhoea gracilis and X. preissii on newly rehabilitated Bauxite mine pits in the jarrah forest of southwestern Australia. Grazing by kangaroos (Macropus fuliginosus) was the major factor in reducing survival and growth of both species during the first 2 years. Provision of artificial grazing protection increased survival and growth (plant mass) of both species by 3-fold. Grazing by native vertebrates has not previously been identified as affecting mine restoration in Western Australia. Initial germination rates from sown seeds of X. preissii at eight replicate sites ranged from 25 to 64% with a mean of 42%. Corresponding figures for X. gracilis were 5–42% with a mean of 17%. Germination of X. gracilis was greater on heavier, moister soils, but X. preissii germinated better on sandier soils. High levels of initial germination did not ensure high survival. Plants of both species grew bigger and survived better on the lighter, sandy soils. Xanthorrhoea seedlings located in the depressions created by the ripping process grew larger than seedlings on the slopes of the riplines. The presence of plants of other species did not have a significant effect on survival. However, these plants facilitated the growth of both species when artificial grazing protection was unavailable. Plants of other species reduced the growth rates of Xanthorrhoea seedlings where artificial grazing protection was provided. Artificial shade by itself had no significant effect on growth of either species. In rehabilitated Bauxite Mines in the jarrah forest, the provision of grazing protection is recommended to ensure successful establishment and early survival of Xanthorrhoea spp.
William A Loneragan - One of the best experts on this subject based on the ideXlab platform.
-
ectomycorrhizal fungal communities of rehabilitated Bauxite Mines and adjacent natural jarrah forest in western australia
International Conference on Multimedia Information Networking and Security, 2008Co-Authors: M Glen, William A Loneragan, Neale L Bougher, I J Colquhoun, S Vlahos, P A Obrien, G E St J HardyAbstract:Abstract Species richness and species composition of ectomycorrhizal (EM) fungi were compared among rehabilitated mine sites and unmined jarrah forest in southwest Western Australia. Species richness, measured in 50 m × 50 m plots, was high. In the wetter, western region, mean species richness per plot in 16-year-old rehabilitated mine sites (63.7 ± 2.5, n = 3) was similar to that of unmined jarrah forest (63.6 ± 9.6, n = 9). In the drier, eastern region, species richness in 12-year-old rehabilitated mine sites (40.3 ± 2.1, n = 3) approached that of nearby forest (52.4 ± 9.3, n = 9). Species composition was analysed by detrended correspondence analysis. Rehabilitated sites of similar age clustered together in the analysis and species composition was closer to the native jarrah forest in the older rehabilitated plots. In unmined forest, species composition of fungal communities in the wetter, western region was different from communities in the drier, eastern region.
-
fire management implications of fuel loads and vegetation structure in jarrah forest restoration on Bauxite Mines in western australia
Forest Ecology and Management, 2004Co-Authors: Martin A Smith, William A Loneragan, Carl D. Grant, John M. KochAbstract:Abstract Bauxite Mines being restored to native jarrah (Eucalyptus marginata)-dominated forest in Western Australia have accumulated substantial fuel loads. Assessment of fire management aspects is necessary for the effective integration of restored areas into forest-wide management. Fuel characteristics, vegetation structure and fire behaviour of young (5- and 8-year-old) restored Bauxite Mines in Western Australia were examined. Pre-burn fuel loads were moderate in 5-year-old restoration (15.0 t ha−1) and high in 8-year-old restoration (29.8 t ha−1). Large ranges in available fuel load estimates of sample sites (2.2–60.8 t ha−1) indicated the heterogeneous nature of fuel distribution leading to variable fire behaviour. The vegetation structure of restored areas differed from that of the unmined jarrah forest due to the presence of a prominent mid-storey layer composed of number of acacias (Acacia pulchella, A. celastrifolia, A. extensa, A. drummondii and A. lateriticola). This mid-storey layer contributed 49% of the total fuel load in 5-year-old restoration, although the high proportion of live material (73.6%) inhibited fire development. In 8-year-old restoration the mid-storey layer contributed 46% of the total fuel load. The lower proportion of live material in these sites (27.9%), due to the senescence and death of the relatively short-lived acacias, led to increased fire intensities, flame heights and higher levels of crown scorch and defoliation. Prescribed burns were conducted in early summer 1997. Burns in 5-year-old restoration were of low intensity ( 7000 kW m−1). Fuel re-accumulation was rapid in the first 2 weeks post-burn, with litter-fall rates 2–3.5 times that of unburnt control sites. Thereafter, litter-fall and fuel accumulation in burnt restored and unmined sites was comparable to that of unburnt control sites. Analysis of 1 and 2 years post-burn 5-year-old restoration indicated that the prescribed burns had failed to remove the mid-storey acacia layer and actually increased the proportion of dead standing material, whereas in the 8-year-old restoration, the prescribed burns removed the mid-storey layer of acacia shrubs and stimulated an increase in the proportion of live plant material, particularly near ground level. Maximum soil temperatures recorded by heat sensitive crayons exceeded 300 °C in 8-year-old restoration burns but were less than 100 °C in 5-year-old restoration burns. Hard-seeded species were stimulated to germinate in the top 2–3 cm of the soil following burns in 8-year-old restoration and only in the top 0.5 cm of the soil following burns in 5-year-old restoration. Some seeds in the top 1 cm of the soil may also have been killed by the high temperatures generated in burns in the 8-year-old sites. Fire management of jarrah forest restoration will have to be different to that employed in unmined jarrah forest due to differences in fuel characteristics, vegetation structure and fire behaviour.
-
the effects of burning on the understorey composition of rehabilitated Bauxite Mines in western australia community changes and vegetation succession
Forest Ecology and Management, 2001Co-Authors: Carl D. Grant, William A LoneraganAbstract:Abstract The first 2 years of post-burn vegetation succession of 11–13-year-old rehabilitated Bauxite Mines in Western Australia is compared to the native jarrah ( Eucalyptus marginata ) forest using the techniques of ordination (CANOCO TM ) and classification (TWINSPAN TM ). Analyses of understorey species density and cover values showed consistent patterns of composition and abundance between the native jarrah forest and the rehabilitated areas, both before and after burning. These patterns resulted from the intentional establishment of high densities of legume species in the initial rehabilitation process and proliferation of high densities of seeding species and non-native eucalypt seedlings following burning of the rehabilitated areas, features not characteristic of native jarrah forest. Burnt sites showed larger changes in species abundance and composition than unburnt control sites as indicated by their relative shift of position in the ordination hyper-space. This shift in position was generally less for sites burnt in spring than sites burnt in autumn. The first two divisions of the site classifications separated the unburnt sites and early spring post-burn sites from the forest and the remainder of the post-burn sites. The species classification showed that each of these groups was associated with a specific suite of species. Pit age (i.e. 11, 12 or 13 years-old at time of burning) was an important determinant of species composition in both the ordinations and classifications. Although species densities recovered more rapidly than live plant cover in the rehabilitated areas following burning, the vegetation of these rehabilitated sites exhibited little evidence of returning to their pre-fire species composition and abundance after 2 years. However, the high species similarity (75–79%) between the pre-burn (including species only present as seed in the topsoil) and post-burn vegetation indicates the importance of the initial floristic composition in determining the potential direction of the post-fire succession.
-
the effects of burning on the understorey composition of 11 13 year old rehabilitated Bauxite Mines in western australia
Plant Ecology, 1999Co-Authors: Carl D. Grant, William A LoneraganAbstract:Alcoa of Australia Limited has been rehabilitating Bauxite Mines in the jarrah (Eucalyptus marginata) forest of Western Australia for more than 30 years. Mines rehabilitated in the early 1980s using out-dated methods have built up substantial fuel loads that may be reduced through prescribed burning. The vegetation response of 11–13 year-old rehabilitated Bauxite Mines to fire regimes differing in intensity and season over the first two years of post-burn succession is compared to the native jarrah forest. A total of 243 species from 137 genera and 56 families were identified in the native forest reference sites and in the 11–13 year-old rehabilitated areas before and after burning. The vegetation of the pre-burn rehabilitated areas was very different to that of the native jarrah forest. While total live plant cover, Acacia density, non-native eucalypt seedling density, weed density and the evenness index were similar between the two areas, total plant density, live Acacia cover, the proportion of weeds, native species numbers and diversity were significantly different. However, the greatest difference between the vegetation of the pre-burn rehabilitated sites and the native jarrah forest was the higher dominance of seeding species (plants killed by fire) in rehabilitated areas. In contrast, native jarrah forest was dominated by resprouting species (plants that survive fire). Burning the rehabilitated sites was successful in making the areas more similar to the forest in terms of total plant density, live Acacia cover and native species numbers but decreased their similarity in terms of live plant cover, Acacia density, non-native eucalypt seedling density, weed density and evenness. The vegetation response of the rehabilitated areas to different seasons of burning showed that autumn burning led to a greater increase in plant establishment than spring burning. Autumn burning also resulted in an undesirable increase in the density of non-native eucalypt seedlings that was not observed following spring burning. Although burning these 11–13 year-old rehabilitated sites will increase similarity to the native forest, it is unlikely that they will resemble the native jarrah forest without further management intervention.
-
fuel characteristics vegetation structure and fire behaviour of 11 15 year old rehabilitated Bauxite Mines in western australia
Australian Forestry, 1997Co-Authors: Carl D. Grant, John M. Koch, William A Loneragan, D T BellAbstract:Summary Bauxite Mines rehabilitated in the early 1980s in Western Australia have built up substantial fuel loads that may be reduced through prescription burning. Fuel characteristics, vegetation structure and fire behaviour of 11–15 year-old rehabilitated Bauxite Mines were examined. Fuel loads were high in all pre-burn rehabilitation areas (23.4–35.1 t ha−1) although large ranges in fuel load estimates of sample plots (6.3–49.3 t ha−1) indicated the heterogenous nature of the fuel distribution that led to heterogeneity in fire behaviour. The vegetation structure of the rehabilitated areas differed from that of the native jarrah forest due to a lower proportion of live to dead plant material and the presence of a prominent mid-storey layer composed of dead Acacia plants. This mid-storey layer contributed 45% of the total fuel load and led to increased flame heights and subsequent higher levels of crown scorch regardless of the soil and litter moisture conditions. Seven prescription burns were carried out...
Jonathan Majer - One of the best experts on this subject based on the ideXlab platform.
-
arthropods in coarse woody debris in jarrah forest and rehabilitated Bauxite Mines in western australia
Annals of Forest Science, 2010Co-Authors: John M. Koch, Andrew H Grigg, Ross K Gordon, Jonathan MajerAbstract:• Coarse woody debris (CWD) is returned to Alcoa’s rehabilitated mined areas in the jarrah forest as potential vertebrate fauna habitat, however, its value for invertebrate fauna has not been investigated. We sought to determine if CWD in rehabilitated areas supported a similar arthropod fauna to that on fallen logs in the adjacent unmined jarrah forest. • Using emergence tents, sampling from logs in 5-year old and 15-year old rehabilitated forest, and in unmined forest, yielded 2266 specimens from 187 taxa. Collembola (43% of total) and Acarina (32%) were the most abundant groups, followed by Diptera (11%), Araneae (4%) and Coleoptera (3%). • There were no significant differences in either taxa richness or overall abundance among the three forest types. However, community composition varied significantly. Species richness from the Araneida, Coleoptera and Diptera was highest in the 5-year old rehabilitated forest, while Collembola and Acarina were better represented in the unmined forest; this was related to changes in the environment surrounding the logs as rehabilitated forest develops, and to log condition. The composition of arthropods on logs in the 15-year old rehabilitated forest was intermediate, indicating a trend of increasing similarity to the unmined forest in arthropod fauna as the rehabilitated forest ages. • We suggest that over longer time periods, CWD in rehabilitated forest will support arthropod communities similar to those found in unmined forest. Future work should determine if returning logs to mined areas facilitates the return of CWD-dependent taxa.
-
long term recolonization patterns of ants in western australian rehabilitated Bauxite Mines with reference to their use as indicators of restoration success
Journal of Applied Ecology, 1998Co-Authors: Jonathan Majer, O NicholsAbstract:1. The return of invertebrate animals to rehabilitated mine pits is desirable for the re-establishment of ecosystem functioning. A long-term ant monitoring programme is reported over 14 years in a jarrah Eucalyptus marginata forest control plot and in three Bauxite mine pits, one of which had been left unvegetated, one planted with marri trees E. calophylla and the other seeded with mixed native plant species. 2. The results confirm published findings for the first 2 years of the succession that seeding with mixed species results in a more rapid attainment of a forest-like ant fauna, although in the last 6 years of the study the ant fauna of the planted plot had become more similar to that of the seeded plot. 3. Changes in the nature of the ant fauna are described and it is concluded that although composition has substantially converged on that of the forest by the end of the study, differences still persist. 4. Research on vegetation, spiders and ants in Bauxite mined areas which have been rehabilitated using more recent technology suggest that these differences will lessen with time and with the introduction of improved rehabilitation prescriptions. 5. An additional aim of the study was to validate the chronosequence approach to studying ecosystem recovery following disturbances such as mining. It is concluded that long-term studies provide important information that is missed by the chronosequence approach. Ideally, rapid-feedback chronosequence approaches should be augmented by long-term case studies.
-
ant recolonization of rehabilitated Bauxite Mines at trombetas para brazil
Journal of Tropical Ecology, 1996Co-Authors: Jonathan MajerAbstract:Ant species were sampled in three rainforest and 10 rehabilitated Bauxite mine plots at Trombetas, in the tropical monsoonal region of Brazil. Rehabilitation ranged from 0 to 11 years in age and was mainly performed by planting mixed native forest tree species. One plot supported single-species blocks of Australian Eucalyptus and Acacia species. Two hundred and six ant species were recorded, of which 82 were exclusively found in the native vegetation, 54 were confined to the rehabilitation and 70 were found in both situations. In contrast with other studies, ant species richness in the Eucalyptus/Acacia plantation was as great as in the areas rehabilitated with native vegetation. The overall rate of return of ant species was considerably greater than in Mines situated within subtropical regions of Brazil, Africa and Australia. However, if the greater richness of ants in the native vegetation at Trombetas was accounted for, the proportional return of the original ant fauna was not particularly rapid. The return of ant species slowed as the rehabilitated areas aged. In comparison with forest, the rehabilitation was characterized by proportionately more generalist species and fewer specialists, especially from the soil and litter layers. The full range of habitat requirements for the ant community has not been restored by the eleventh year of rehabilitation and further management may be required to enhance the degree of colonization. It is suggested that the findings for ants may apply to other components of the biota as well.
-
a comparative study of spider araneae communities of rehabilitated Bauxite Mines and surrounding forest in the southwest of western australia
Restoration Ecology, 1994Co-Authors: S J Simmonds, Jonathan Majer, Owen G NicholsAbstract:A study of spider (Araneae) communities was conducted in rehabilitated Bauxite Mines at the Jarrahdale mine site of Alcoa of Australia Ltd. and in the nearby native jarrah (Eucalyptus marginata) forest in southwest Western Australia. The study was conducted from March to August 1993 in five rehabilitated sites of different age and method of rehabilitation and in two forest sites. A variety of collection methods was used, including pitfall trapping, litter sampling, sweep netting, tree beating, and visual searching. These methods were the same as those carried out in a previous study of some of these areas in 1983. We collected 151 spider species belonging to 102 genera and 34 families. We examined the relationship between various habitat features, including the age and method of rehabilitation, of the spider communities present. It was found that leaf litter depth and cover and vegetation density had a significant positive influence on recolonization by the various spider guilds. The age and method of rehabilitation were found to influence different vegetational and habitat features; these, in turn, influenced the spider communities. Thus, the older a rehabilitated site the greater the species richness of both plants and spiders. We compared these results with those of the 1983 study to determine the spider succession of the aging rehabilitation. The spider communities and guild composition were found to change as the vegetation matured, from a dominance of pioneer species to a community of species requiring less harsh conditions. By comparison with the pre-1983 rehabilitation, the latest method of rehabilitation increased the rate of recolonization by both plants and spiders.
-
recolonization by collembola of rehabilitated Bauxite Mines in western australia
Austral Ecology, 1993Co-Authors: Penelope Greenslade, Jonathan MajerAbstract:Abstract The collembolan faunas of 30 Bauxite Mines rehabilitated by a range of different methods between 1966 and 1977, and three forest plots were surveyed in the spring and summer of 1978–79 with the aim of studying the restoration of decomposer activity in degraded areas. The rehabilitation methods included seeding and planting with a variety of native or exotic plant species. Physical and botanical parameters of the plots were also measured. Sixty species of Collembola were collected from the rehabilitated areas; nine of the 28 species found in the forest plots were not present on the mined sites. Principal components analysis suggested that the species richness of the collembolan community in rehabilitated areas is positively correlated with plot age. A parametric correlation analysis using a number of collembolan community characteristics revealed that, among other factors, the development of a species rich collembolan fauna is positively correlated with plant species richness and diversity, and also with percentage plant cover. These results provide directions for improving rehabilitation practices.
Nicholas De Klerk - One of the best experts on this subject based on the ideXlab platform.
-
all cause mortality and incidence of cancer in workers in Bauxite Mines and alumina refineries
International Journal of Cancer, 2008Co-Authors: Lin Fritschi, Ewan Macfarlane, Jan Lucas Hoving, Geza Benke, Anthony Del Monaco, Dean Philip Mckenzie, Nicholas De KlerkAbstract:Bauxite is a reddish clay that is refined to produce alumina, which is then reduced to aluminium. There have been studies examining the health of workers in aluminium smelters, but not workers in Bauxite mining and alumina refining. A cohort of employees of 1 large aluminium company since 1983 was assembled (n 5 6,485, 5,828 men). Deaths and incident cancers to 2002 were ascertained by linkage to national and state cancer and death registries. SIRs and SMRs were calculated compared to national rates standardizing for calendar year, sex and 5-year age group. The mortality from all causes (SMR 0.68, 95% CI: 0.60–0.77), and from circulatory and respiratory diseases, all cancers combined and injury in the male cohort were lower than in the Australian male population and were similar across work groups and with duration of employment. The only significant increased mortality risk was from pleural mesothelioma. The incidence of all cancers combined was similar to the Australian rate. The cohort had a lower risk of incident lymphohaematopoietic cancer (SIR 0.50, 95% CI: 0.31– 0.88) and a higher risk of melanoma (SIR 1.30, 95% CI: 1.00– 1.69) although no dose-responses were seen. There was also an increased risk of mesothelioma (SIR 3.49, 95% CI: 1.82–6.71), which was associated with exposures outside the aluminium industry. This study is the first to examine cancer and mortality amongst workers in Bauxite Mines and alumina refineries and found little evidence for increased cancer incidence or mortality in these workers. ' 2008 Wiley-Liss, Inc.
-
All cause mortality and incidence of cancer in workers in Bauxite Mines and alumina refineries
International Journal of Cancer, 2008Co-Authors: Lin Fritschi, Malcolm R. Sim, Anthony Del Monaco, Ewan Macfarlane, Dean Mckenzie, Jan Lucas Hoving, Geza Benke, Nicholas De KlerkAbstract:Bauxite is a reddish clay that is refined to produce alumina, which is then reduced to aluminium. There have been studies examining the health of workers in aluminium smelters, but not workers in Bauxite mining and alumina refining. A cohort of employees of 1 large aluminium company since 1983 was assembled (n = 6,485, 5,828 men). Deaths and incident cancers to 2002 were ascertained by linkage to national and state cancer and death registries. SIRs and SMRs were calculated compared to national rates standardizing for calendar year, sex and 5-year age group. The mortality from all causes (SMR 0.68, 95% CI: 0.60-0.77), and from circulatory and respiratory diseases, all cancers combined and injury in the male cohort were lower than in the Australian male population and were similar across work groups and with duration of employment. The only significant increased mortality risk was from pleural mesothelioma. The incidence of all cancers combined was similar to the Australian rate. The cohort had a lower risk of incident lymphohaematopoietic cancer (SIR 0.50, 95% CI: 0.31-0.88) and a higher risk of melanoma (SIR 1.30, 95% CI: 1.00-1.69) although no dose-responses were seen. There was also an increased risk of mesothelioma (SIR 3.49, 95% CI: 1.82-6.71), which was associated with exposures outside the aluminium industry. This study is the first to examine cancer and mortality amongst workers in Bauxite Mines and alumina refineries and found little evidence for increased cancer incidence or mortality in these workers.