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Habitat Manipulation (habitat + manipulation)
Selected AbstractsResponse of small rodents to manipulations of vegetation height in agro-ecosystemsINTEGRATIVE ZOOLOGY (ELECTRONIC), Issue 1 2008Jens JACOB Abstract Some small mammal populations require human interference to conserve rare or threatened species or to minimize adverse effects in plant production. Without a thorough understanding about how small rodents behave in their environment and consideration of how they react to management efforts, management will not be optimal. Social behavior, spatial and temporal activity patterns, predator avoidance and other behavioral responses can affect pest rodent management. Some of these behavioral patterns and their causes have been well studied. However, their impact on pest rodent management, especially for novel management approaches, is not always clear. Habitat manipulation occurs necessarily through land use and intentionally to reduce shelter and food availability and to increase predation pressure on rodents. Rodents often respond to decreased vegetation height with reduced movements and increased risk sensitivity in their feeding behavior. This seems to result mainly from an elevated perceived predation risk. Behavioral responses may lessen the efficacy of the management because the desired effects of predators might be mediated. It remains largely unknown to what extent such responses can compensate at the population level for the expected consequences of habitat manipulation and how population size and crop damage are affected. It is advantageous to understand how target and non-target species react to habitat manipulation to maximize the management effects by appropriate techniques, timing and spatial scale without causing unwanted effects at the system level. [source] Habitat structure mediates predation risk for sedentary prey: experimental tests of alternative hypothesesJOURNAL OF ANIMAL ECOLOGY, Issue 3 2009Anna D. Chalfoun Summary 1Predation is an important and ubiquitous selective force that can shape habitat preferences of prey species, but tests of alternative mechanistic hypotheses of habitat influences on predation risk are lacking. 2We studied predation risk at nest sites of a passerine bird and tested two hypotheses based on theories of predator foraging behaviour. The total-foliage hypothesis predicts that predation will decline in areas of greater overall vegetation density by impeding cues for detection by predators. The potential-prey-site hypothesis predicts that predation decreases where predators must search more unoccupied potential nest sites. 3Both observational data and results from a habitat manipulation provided clear support for the potential-prey-site hypothesis and rejection of the total-foliage hypothesis. Birds chose nest patches containing both greater total foliage and potential nest site density (which were correlated in their abundance) than at random sites, yet only potential nest site density significantly influenced nest predation risk. 4Our results therefore provided a clear and rare example of adaptive nest site selection that would have been missed had structural complexity or total vegetation density been considered alone. 5Our results also demonstrated that interactions between predator foraging success and habitat structure can be more complex than simple impedance or occlusion by vegetation. [source] Responses of two species of heathland rodents to habitat manipulation: Vegetation density thresholds and the habitat accommodation modelAUSTRAL ECOLOGY, Issue 3 2010VAUGHAN MONAMY Abstract The abundance of two native rodent species, Rattus lutreolus and Pseudomys gracilicaudatus, has been shown to correlate with vegetation density in coastal wet heath. Fox's habitat accommodation model relates relative abundances of such small mammal species to heathland vegetation regeneration following disturbance. Implicit in the model is recognition that it is successional changes in vegetation, not time per se, that drives the responses of small mammal species along a regeneration axis. Using a brush-cutter we deliberately removed approximately 85% of vegetation around trapping stations and recorded significant reductions in the abundance of both P. gracilicaudatus (an earlier-stage colonizing species) and R. lutreolus (a late seral-stage species). A significant decrease in the abundance of only the latter had been demonstrated previously when 60,70% of the vegetation had been removed. Following the brush-cutting both species re-entered the mammalian secondary succession at different times, first P. gracilicaudatus followed by R. lutreolus after the vegetation cover thresholds of each species had been reached. The impact of this habitat manipulation experiment was to produce a retrogression of the small mammal succession, experimentally demonstrating causality between changes in vegetation density and subsequent small mammal habitat use. [source] Review: Alternatives to synthetic fungicides for Botrytis cinerea management in vineyardsAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 1 2010M.A. JACOMETTI Abstract Botrytis cinerea (Pers.: Fr), the causal agent of botrytis bunch rot, is an important disease of grapevines worldwide, with canopy management and the prophylactic use of fungicides being the most common control methods. The latter has resulted in fungicide resistance and is increasingly raising concerns regarding residues in wine and effects on human and environmental health. Research-led alternatives to this practice are beginning to emerge, including a range of biotic and abiotic treatments that induce vine resistance to B. cinerea and inundative applications of biological control agents such as Trichoderma, Bacillus, Ulocladium and Streptomyces species. Also, habitat manipulation techniques that aim to improve the effectiveness of naturally occurring biological control are being developed using mulches brought into the vineyard, as well as mulched cover crops. These can accelerate decomposition of botrytis mycelium and sclerotia on the vineyard floor in winter. The challenges of these different techniques and the prospects for habitat manipulation for this fungal disease are discussed. Extensive tables on synthetic fungicides, biofungicides, essential oils and plant extracts effective against B. cinerea are included. [source] Influence of non-crop plants on stink bug (Hemiptera: Pentatomidae) and natural enemy abundance in tomatoesJOURNAL OF APPLIED ENTOMOLOGY, Issue 8 2010C. G. Pease Abstract We investigated the effects of weed hosts on stink bug density and damage (Euschistus conspersus Uhler and Thyanta pallidovirens Stal), and a nectar bearing plant on natural enemies of stink bugs in the Sacramento Valley of California. Stink bug density and fruit damage were evaluated in processing tomatoes adjacent to weedy and cultivated borders. The density of E. conspersus was significantly greater in tomatoes adjacent to weedy borders in July but not during August/September. Thyanta pallidovirens was less abundant overall (19%), but was found in significantly greater densities adjacent to cultivated borders in July but not in August/September. Mean percent fruit damage by stink bugs was greater adjacent to the weedy border than the cultivated border, but this difference was not significant. Stink bug egg parasitism and generalist predator density were evaluated in fresh market tomatoes adjacent to a sweet alyssum (Lobularia maritima L.) border and an unplanted control border at three sites. Egg parasitism was significantly greater in the alyssum treatment for the 9,12 September sampling period. Jalysus wickhami VanDuzee (Hemiptera: Berytidae) density was significantly greater in the alyssum treatment in mid-June. No other significant differences in predator populations were detected. Results of these two studies show that habitat manipulations have the potential to reduce densities of E. conspersus in tomato, the first step in developing a farmscape management plan for stink bug control. [source] Status of galaxiid fishes in Tasmania, Australia: conservation listings, threats and management issuesAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 3 2006Scott A. Hardie Abstract 1.Fish of the family Galaxiidae are restricted to the southern hemisphere where they occupy a diverse array of habitats ranging from over 2000 m in elevation to sea level. Some species are diadromous and, hence, freshwater, estuarine and marine habitats are used during their life-cycle; other species complete their entire life-cycles in freshwater environments. 2.Tasmania has a diverse galaxiid fauna that accounts for 64% of native freshwater fish species found on the island. The Tasmanian galaxiid fauna is characterized by high species richness (5 genera and 16 species), endemism (11 species), restricted distributions, and non-diadromous life histories (11 species). 3.The galaxiid fauna of Tasmania has significant conservation status with 69% of species considered ,threatened'. The conservation status of the fauna is recognized at State, national and international levels. 4.The key threats to galaxiids in Tasmania are exotic species, hydrological manipulations, restricted distributions, general habitat degradation and exploitation of stocks. 5.Although work has recently been undertaken to conserve and manage Tasmanian galaxiid populations, the fauna is still thought to be imperilled. Knowledge gaps that need to be addressed include the biology and ecology of most species (e.g. reproductive biology, life histories, habitat use and requirements) and impacts of habitat manipulations, as well as mechanisms and impacts of interactions with exotic species. Techniques to monitor accurately the status of galaxiid species and their populations need to be developed and the coexistence of some galaxiids with introduced salmonids should also be examined. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||