49 resultados para marine community dynamics

em Deakin Research Online - Australia


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Aim: This paper aims to explore frail older women’s lived experiences of ‘community’ and which aspects of ‘community’ they perceive as beneficial to their well-being.

Method: This qualitative project used a mixed methodological approach which integrated aspects of descriptive phenomenology and grounded theory. Ten frail, older women residing in South East Melbourne, Australia participated in in-depth interviews.

Results: This research obtained a rich and detailed account of the aspects of ‘community’ identified by participants as enhancing their well-being. These included: social contact, community dynamics, feelings of support and positive orientation.

Conclusion: This paper has increased our understanding of the factors supporting well-being of frail older women. Service providers should actively consider how they can strengthen these factors to improve social connectedness for frail older women by the use of volunteers, developing social networks and increasing availability and quality of community-based activities.

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Ontogenetic allometries in ecological habits and niche use are key responses by which individuals maximize lifetime fitness. Moreover, such allometries have significant implications for how individuals influence population and community dynamics. Here, we examined how body size variation in Komodo dragons (Varanus komodoensis) influenced ecological allometries in their: (1) prey size preference, (2) daily movement rates, (3) home range area, and (4) subsequent niche use across ontogeny. With increased body mass, Komodo dragons increased prey size with a dramatic switch from small (≤10 kg) to large prey (≥50 kg) in lizards heavier than 20 kg. Rates of foraging movement were described by a non-linear concave down response with lizard increasinghourly movement rates up until ∼20 kg body mass before decreasing daily movement suggesting reduced foraging effort in larger lizards. In contrast, home range area exhibited a sigmoid response with increased body mass. Intrapopulation ecological niche use and overlap were also strongly structured by body size. Thus, ontogenetic allometries suggest Komodo dragon’s transition from a highly active foraging modeexploiting small prey through to a less active sit and wait feeding strategy focused on killing large ungulates. Further, our results suggest that as body size increases across ontogeny, the Komodo dragon exhibited marked ontogenetic niche shifts that enabled it to function as an entire vertebrate predator guild by exploiting prey across multiple trophic levels.

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Recent research suggests that the behavior of individuals under risk of predation could be a key link between individual behavior and population and community dynamics. Yet existing theory remains largely untested at large spatial and temporal scales. We manipulated food available to age-0 rainbow trout while at risk of cannibalism, in a replicated factorial whole-lake experiment, to test whether the trade-off between growth and mortality rates is mediated by foraging activity by young fish under predation risk. We found that this trade-off exists for young fish at the whole-system scale, and that food-dependent behavioral variation has large mortality consequences. In high-food lakes, age-0 trout spent less time moving, fewer individuals swam continuously, and those swimming continuously swam at slower speeds relative to those in low-food lakes. Age-0 trout also used deep, risky habitats less when food was abundant. This lower activity, combined with avoidance of risky habitats, coincided with 68% higher survival in high-food lakes. If general, this trade-off may be a key mechanism linking individual behavior to population-level processes in size-structured populations.

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Animal migrations span the globe, involving immense numbers of individuals from a wide range of taxa. Migrants transport nutrients, energy, and other organisms as they forage and are preyed upon throughout their journeys. These highly predictable, pulsed movements across large spatial scales render migration a potentially powerful yet underappreciated dimension of biodiversity that is intimately embedded within resident communities. We review examples from across the animal kingdom to distill fundamental processes by which migratory animals influence communities and ecosystems, demonstrating that they can uniquely alter energy flow, food-web topology and stability, trophic cascades, and the structure of metacommunities. Given the potential for migration to alter ecological networks worldwide, we suggest an integrative framework through which community dynamics and ecosystem functioning may explicitly consider animal migrations.

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Fire is an integral disturbance shaping forest community dynamics over large scales. However, understanding the relationship between fire induced habitat disturbance and biodiversity remain equivocal. Ecological theories including the intermediate disturbance hypothesis (IDH) and the habitat accommodation model (HAM) offer predictive frameworks that could explain faunal responses to fire disturbances. We used an 80 year post-fire chronosequence to investigate small reptile community responses to fires in temperate forests across 74 sites. First, we evaluated if changes in species richness, abundance and evenness post-fire followed trends of prior predictions, including the IDH. Second, using competing models of fine scale habitat elements we evaluated the specific ways which fire influenced small reptiles. Third, we evaluated support for the HAM by examining compositional changes of reptile community post-fire. Relative abundance was positively correlated to age post-fire while richness and evenness showed no associations. The abundance trend was as expected based on the prior prediction of sustained population increase post-disturbance, but the trend for richness contradicted the prediction of highest diversity at intermediate levels of disturbance (according to IDH). Abundance changes were driven mainly by changes in overstorey, ground layer, and shelter, while richness and evenness did not associate with any vegetation parameter. Community composition was not strongly correlated to age since fire, thus support for the HAM was weak. Overall, in this ecosystem, frequent fire disturbances can be detrimental to small reptiles. Future studies utilizing approaches based on species traits could enhance our understanding of biodiversity patterns post-disturbance.

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This study investigated community-based monitoring in Victoria’s Marine National Parks (MNPs) and Sanctuaries (MSs) from January to May 2004. The primary aim of this study was to evaluate the potential for community-based monitoring projects to assist in the collection of data for the management of Victoria’s MNPs and MSs. The pilot habitats that were assessed included subtidal reefs at the Merri MS, intertidal reefs at Ricketts Point MS and seagrass beds at Corner Inlet MNP. The three main objectives for this study were to:
 - Develop a template for the monitoring of marine habitats by community groups.
 - Assess the quality and integrity of data collected by community volunteers.
 - Determine a sustainable model for community monitoring of marine habitats.
Three standard operating procedures (SOPs) in the form of a “how to” manual, were developed for each habitat type. The SOPs were adapted from scientifically robust studies and developed in consultation with community volunteer groups by means of field trials. Volunteer feedback assisted in the final SOP design. The SOP will allow Parks Victoria Rangers to develop community-based programs within the parks. The SOPs are accessible as Parks Victoria Technical Series Numbers 16, 17 and 18. Data collected by volunteers across the three habitat sites were assessed and compared to that collected by scientists. It was found that data quality collected by volunteers was dependent on habitat type and the type of measurement the volunteer was required to assess. Volunteer estimation measurements were highly variable across all three habitat sites, compared to quantitative data collection. Subtidal monitoring had the greatest potential for inconsistency in data collection. Intertidal monitoring is the most sustainable of the three habitat monitoring procedures. Sustainability of community-based monitoring programs is dependent on continued support and training by the management authority of Victoria’s MNPs and MSs. For the expansion of the monitoring programs to other MNPs and MSs, the management authority could expand strong relationships with the community volunteer groups.

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There is an increasing realisation of the importance of community or volunteer collected data for management programs that are otherwise limited by the availability of funds or resources. However, there are concerns regarding the reliability of scientific data collected by inexperienced people. We investigated the potential for community-based monitoring in Victoria’s newly established system of Marine Protected Areas. The main objectives for the study were to 1) develop a template for the scientific monitoring of marine habitats suitable for community groups, 2) assess data quality and data integrity collected by community volunteers and 3) determine a sustainable model for ongoing community participation in monitoring marine habitats. Three different habitats (subtidal, intertidal, and seagrass) were investigated and data collected by volunteers across these habitats was compared to that collected by scientists. Reliability of data collected by volunteers was dependent on habitat type and the type of measurement the volunteers were required to make. Qualitative estimates made by volunteers were highly variable across all three habitat sites, compared to quantitative data collection. Subtidal monitoring had the greatest inaccuracy for data collection, whereas intertidal reef monitoring was most reliable. Sustainability of community-based monitoring programs is dependent on adequate training for volunteers and the development of partnerships to foster greater community engagement.

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In 2004, a Community Based Monitoring (CBM) program for Victoria’s Marine National Parks and Marine Sanctuaries was developed. A key performance area for Victoria’s Marine Protected Area (MPA) Management Strategy is community engagement. This program was developed to incorporate the key performance principles of community education, participation and engagement. CBM involves scientific protocols to monitor different habitat types in a MPA. As part of the CBM project, perceptions and values of MPAs were investigated through a pilot survey of 125 community group volunteers from 4 volunteer groups. Surveys were sent to all community group members which included participants and non-participants in the CBM program. Questions sought qualitative and quantitative information, focusing on personal values of MPAs. The surveys included questions associated with CBM, MPA management and environmental issues affecting the marine environment. Responses from the pilot study indicated that 50% of the volunteers participated in CBM to learn more about scientific research, and 30% wanted to work close to nature. This pilot study will form the basis of a larger-scale study to investigate community group perceptions of MPAs and identifying how to maintain volunteer enthusiasm, interest and motivation in a CBM program.

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In recent years there has been an increase in community-based monitoring programmes developed and implemented worldwide. This paper describes how the data collected from such a programme could be integrated into a Geographic Information System (GIS) to create temperate subtidal marine habitat maps. A differential Global Positioning System was utilized to accurately record the location of the trained community-based SCUBA diver data. These georeferenced data sets were then used to classify benthic habitats using an aerial photograph and digitizing techniques. This study demonstrated that trained community-based volunteers can collect data that can be utilized within a GIS to create reliable and cost-effective maps of shallow temperate subtidal rocky reef systems.