Fire effects on pollination in a sexually deceptive orchid

2016 ◽  
Vol 25 (8) ◽  
pp. 888 ◽  
Author(s):  
Julian Brown ◽  
Alan York ◽  
Fiona Christie
Keyword(s):  
Prescribed Fire ◽  
Scale Effects ◽  
Spatial Scales ◽  
Fire Effects ◽  
Landscape Scale ◽  
Local Scale ◽  
Agricultural Landscapes ◽  
Pollinator Visitation ◽  
Age Class ◽  
Landscape Scales

Research into the effectiveness of prescribed fire in managing pollination has only recently begun. The effects of fire on pollination have not been explored in sexually deceptive systems. Further, the potential for multiple effects operating at different spatial scales has not been explored in any pollination system despite multiscale effects on pollination observed in agricultural landscapes. We observed the frequency of pollinator visitation to flowers of sexually deceptive Caladenia tentaculata and related it to the post-fire age class of the vegetation at local and landscape scales. We also related the number of the pollinator’s putative larval hosts (scarab beetles) captured at these sites to age class. At the local scale (i.e. the sample location), visitation was highest in recently burnt sites. At the landscape scale, positive associations were observed between (1) putative pollinator hosts and vegetation burnt 36–50 years ago, and (2) pollinator visitation and vegetation burnt ≥50 years ago. Local- and landscape-scale effects on visitation were synergistic, such that visitation was greatest when fire age was heterogeneous within pollinator foraging range.

scholarly journals The Relative Effects of Local and Landscape Characteristics of Hedgerows on Bats

Diversity ◽  
2018 ◽  
Vol 10 (3) ◽  
pp. 72 ◽  
Author(s):  
Aurélie Lacoeuilhe ◽  
Nathalie Machon ◽  
Jean-François Julien ◽  
Christian Kerbiriou
Keyword(s):  
Spatial Scales ◽  
Positive Influence ◽  
Local Scale ◽  
Agricultural Landscapes ◽  
Intensive Agriculture ◽  
Acoustic Survey ◽  
Bat Activity ◽  
Landscape Characteristics ◽  
Landscape Scales

The role of hedgerows in maintaining biodiversity in areas of intensive agriculture is well known, particularly for bats. However, few studies have addressed the importance of the intrinsic characteristics of hedgerows for bats and disentangled the relative effects of local and landscape characteristics of hedgerows on bat activity. In an acoustic survey, we assessed bat activity by recording bat calls using detectors and manually verified all calls using spectrogram analysis. The parameters used to determine local hedgerow structures were the length of the line of trees, of shrub hedgerows, of wooded hedgerows without shrubs and of hedgerows including the three strata (tree, shrub and herb) at a local scale. We assessed the influence of hedgerow structure and on bat activity with an approach considering both species and community, comparing two different scales, the local and the landscape. We highlighted the importance of hedgerow characteristics for bats on both the local and landscape scales even though responses differ between species and spatial scales. We found that the presence of trees in hedgerows exerts a generally positive influence on bat activity and that hedgerows with the three strata had lower bat activity than hedgerows with trees. In our study, some bats seemed to prefer agricultural landscapes dominated by wooded hedgerows and, on the local scale, hedgerows that include trees with little diversified among strata, except for gleaning species. Our study shows that in terms of hedgerow management, conservation efforts must be designed and undertaken on both the local and landscape scales.

scholarly journals Interactions between large herbivores and litter removal by termites across a rainfall gradient in a South African savanna

2011 ◽  
Vol 27 (4) ◽  
pp. 375-382 ◽  
Author(s):  
Robert Buitenwerf ◽  
Nicola Stevens ◽  
Cleo M. Gosling ◽  
T. Michael Anderson ◽  
Han Olff
Keyword(s):  
Plant Biomass ◽  
Spatial Scales ◽  
Landscape Scale ◽  
Local Scale ◽  
Arid Ecosystems ◽  
Annual Rainfall ◽  
Large Herbivores ◽  
Mammalian Herbivores ◽  
Litter Removal ◽  
Semi Arid

Abstract:Litter-feeding termites influence key aspects of the structure and functioning of semi-arid ecosystems around the world by altering nutrient and material fluxes, affecting primary production, foodweb dynamics and modifying vegetation composition. Understanding these complex effects depends on quantifying spatial heterogeneity in termite foraging activities, yet such information is scarce for semi-arid savannas. Here, the amount of litter that was removed from 800 litterbags in eight plots (100 litterbags per plot) was measured in Hluhluwe–iMfolozi Park (HiP) South Africa. These data were used to quantify variation in litter removal at two spatial scales: the local scale (within 450-m2 plots) and the landscape scale (among sites separated by 8–25 km). Subsequently, we attempted to understand the possible determinants of termites’ foraging patterns by testing various ecological correlates, such as plant biomass and bare ground at small scales and rainfall and fences that excluded large mammalian herbivores at larger scales. No strong predictors for heterogeneity in termite foraging intensity were found at the local scale. At the landscape scale termite consumption depended on an interaction between rainfall and the presence of large mammalian herbivores: litter removal by termites was greater in the presence of large herbivores at the drier sites but lower in the presence of large herbivores at the wetter sites. The effect of herbivores on termite foraging intensity may indicate a switch between termites and large herbivore facilitation and competition across a productivity gradient. In general, litter removal decreased with increasing mean annual rainfall, which is in contrast to current understanding of termite consumption across rainfall and productivity gradients. These results generate novel insights into termite ecology and interactions among consumers of vastly different body sizes across spatial scales.

Simulating landscape-scale effects of fuels treatments in the Sierra Nevada, California, USA

2011 ◽  
Vol 20 (3) ◽  
pp. 364 ◽  
Author(s):  
Alexandra D. Syphard ◽  
Robert M. Scheller ◽  
Brendan C. Ward ◽  
Wayne D. Spencer ◽  
James R. Strittholt
Keyword(s):  
Sierra Nevada ◽  
Prescribed Fire ◽  
Plant Biomass ◽  
Fire Regime ◽  
Scale Effects ◽  
Weather Conditions ◽  
Landscape Scale ◽  
Fire Weather ◽  
Fuels Management ◽  
Fuels Treatments

In many coniferous forests of the western United States, wildland fuel accumulation and projected climate conditions increase the likelihood that fires will become larger and more intense. Fuels treatments and prescribed fire are widely recommended, but there is uncertainty regarding their ability to reduce the severity of subsequent fires at a landscape scale. Our objective was to investigate the interactions among landscape-scale fire regimes, fuels treatments and fire weather in the southern Sierra Nevada, California. We used a spatially dynamic model of wildfire, succession and fuels management to simulate long-term (50 years), broad-scale (across 2.2 × 106 ha) effects of fuels treatments. We simulated thin-from-below treatments followed by prescribed fire under current weather conditions and under more severe weather. Simulated fuels management minimised the mortality of large, old trees, maintained total landscape plant biomass and extended fire rotation, but effects varied based on elevation, type of treatment and fire regime. The simulated area treated had a greater effect than treatment intensity, and effects were strongest where more fires intersected treatments and when simulated weather conditions were more severe. In conclusion, fuels treatments in conifer forests potentially minimise the ecological effects of high-severity fire at a landscape scale provided that 8% of the landscape is treated every 5 years, especially if future fire weather conditions are more severe than those in recent years.

Comparisons of spatial patterns between windthrow and logging at two spatial scales

2014 ◽  
Vol 44 (7) ◽  
pp. 740-749 ◽  
Author(s):  
Kaysandra Waldron ◽  
Jean-Claude Ruel ◽  
Sylvie Gauthier ◽  
Philippe Goulet
Keyword(s):  
Spatial Scales ◽  
Natural Disturbance ◽  
Landscape Scale ◽  
Canopy Openness ◽  
Managed Forests ◽  
Eastern Canada ◽  
Spatial Characteristics ◽  
Management Context ◽  
Landscape Scales ◽  
Shape Complexity

Windthrow is a dominant natural disturbance in the boreal forest of eastern Canada. To provide the range of variability of a natural disturbance, its spatial distribution and patch metrics at stand and landscape scales have to be considered, together with the characterization of its severity. Our study characterized both partial windthrow (PW) and total windthrow (TW) spatial distributions at the landscape scale and patchiness within affected stands (stand scale). Landscape scale corresponded to three areas of about 5000 ha. Stand scale was the finest scale of analysis and corresponded to each affected stand within landscapes. In addition, windthrow spatial characteristics were compared with spatial characteristics of harvested areas (CUT). At the landscape scale, our results showed that TW stands were more isolated than PW stands and that mean shape complexity of disturbed stands was low, regardless of whether the disturbance was a windthrow or a harvested area. At the affected stand scale, residual trees covered a significantly higher proportion of PW stands than TW stands and CUT. CUT and TW did not share many spatial characteristics at the stand scale. CUT had a significantly higher proportion of complete canopy openness than TW. Our results showed that PW are spatially heterogeneous at both landscape and stand scales. In an ecosystem management context, i.e., a management that reduces the discrepancy between natural and managed forests, our results showed that forest managers could practice a variety of harvesting methods of different intensities.

scholarly journals Agroecology landscapes

2021 ◽  
Author(s):  
Ph. Jeanneret ◽  
S. Aviron ◽  
A. Alignier ◽  
C. Lavigne ◽  
J. Helfenstein ◽  
...  
Keyword(s):  
Landscape Ecology ◽  
Spatial Scales ◽  
Landscape Scale ◽  
Agroforestry Systems ◽  
Agricultural Landscapes ◽  
Biological Interactions ◽  
Natural Habitats ◽  
Bottom Up ◽  
Context Specific ◽  
Individual Farm

Abstract Context Agroecology combines agronomic and ecological concepts. It relies on the enhancement of biodiversity and related ecosystem services to support agricultural production. It is dependent on biological interactions for the design and management of agricultural systems in agricultural landscapes. Objectives We review the role of landscape ecology to understand and promote biodiversity, pest regulation and crop pollination for the designing of “agroecology landscapes”. We illustrate the use of landscape ecological methods for supporting agroforestry systems as an example of agroecological development, and we propose pathways to implement agroecology at landscape scale. Methods The state of the art of how landscape ecology contributes to agroecology development is summarized based on a literature review. Results Agroecology requires thinking beyond the field scale to consider the positioning, quality and connectivity of fields and semi-natural habitats at larger spatial scales. The spatial and temporal organisation of semi-natural elements and the crop mosaic interact. Understanding this interaction is the pre-requisite for promoting patterns and mechanisms that foster biodiversity and ecosystem service provision. Promoting agroecological practices beyond individual farm borders can be rooted in a bottom-up approach from agroecological lighthouse farms to farm networks to amplify agroecology adoption at the landscape scale. Conclusions Achieving agricultural landscapes composed of fields and farms following agroecological management requires understanding of biodiversity patterns, biological interactions and mechanisms that determine and boost ecosystem functioning to improve services at landscape scale, involving farmers in a bottom-up and context-specific approach.

scholarly journals Importance of Autoinfection to the Epidemiology of Polycyclic Foliar Disease

2009 ◽  
Vol 99 (10) ◽  
pp. 1116-1120 ◽  
Author(s):  
Christopher C. Mundt
Keyword(s):  
Disease Progression ◽  
Spatial Scales ◽  
Landscape Scale ◽  
Local Scale ◽  
Microbial Interactions ◽  
Disease Spread ◽  
Potential Importance ◽  
Plant Populations ◽  
Foliar Disease ◽  
Qualitative And Quantitative

Autoinfection (infection resulting from inoculum produced on the same host unit) can result in strongly clustered disease at the local scale. In contrast, much epidemiological theory incorporates the simplification of spatially random or uniform infection. Earlier studies suggested only low to moderate levels of autoinfection, especially when the host unit is small. However, several studies published within the last 5 years suggest that autoinfection rates may be substantially higher than previously indicated. I discuss the potential importance of accounting for high autoinfection rates in example epidemiological processes that occur at different spatial scales: microbial interactions on the phylloplane, temporal disease progression in plant populations, and spatiotemporal disease spread at the landscape scale. Accounting for high autoinfection rates can have important qualitative and quantitative consequences for epidemiological processes, and further studies of autoinfection will contribute significantly to our understanding of epidemics.

scholarly journals Disentangling multiple drivers of pollination in a landscape-scale experiment

2014 ◽  
Vol 281 (1774) ◽  
pp. 20132667 ◽  
Author(s):  
Christof Schüepp ◽  
Felix Herzog ◽  
Martin H. Entling
Keyword(s):  
Fruit Set ◽  
Landscape Scale ◽  
Agricultural Landscapes ◽  
Pollen Competition ◽  
Floral Resources ◽  
Cherry Tree ◽  
Pollinator Visitation ◽  
Flower Density ◽  
Scale Experiment ◽  
Cherry Trees

Animal pollination is essential for the reproductive success of many wild and crop plants. Loss and isolation of (semi-)natural habitats in agricultural landscapes can cause declines of plants and pollinators and endanger pollination services. We investigated the independent effects of these drivers on pollination of young cherry trees in a landscape-scale experiment. We included (i) isolation of study trees from other cherry trees (up to 350 m), (ii) the amount of cherry trees in the landscape, (iii) the isolation from other woody habitats (up to 200 m) and (iv) the amount of woody habitats providing nesting and floral resources for pollinators. At the local scale, we considered effects of (v) cherry flower density and (vi) heterospecific flower density. Pollinators visited flowers more often in landscapes with high amount of woody habitat and at sites with lower isolation from the next cherry tree. Fruit set was reduced by isolation from the next cherry tree and by a high local density of heterospecific flowers but did not directly depend on pollinator visitation. These results reveal the importance of considering the plant's need for conspecific pollen and its pollen competition with co-flowering species rather than focusing only on pollinators’ habitat requirements and flower visitation. It proved to be important to disentangle habitat isolation from habitat loss, local from landscape-scale effects, and direct effects of pollen availability on fruit set from indirect effects via pollinator visitation to understand the delivery of an agriculturally important ecosystem service.

scholarly journals Effects of Aphid Density and Plant Taxa on Predatory Ladybeetle Abundance at Field and Landscape Scales

Insects ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 695
Author(s):  
Hongsheng Pan ◽  
Bing Liu ◽  
Coline C. Jaworski ◽  
Long Yang ◽  
Yongqiang Liu ◽  
...  
Keyword(s):  
Plant Species ◽  
Local Field ◽  
Growing Season ◽  
Landscape Scale ◽  
Agricultural Landscapes ◽  
Field Scale ◽  
Diverse Range ◽  
Positive Correlation ◽  
Regional Landscape ◽  
Landscape Scales

In agroecosystems, predatory ladybeetles play an important role in restraining aphid population growth and suppressing aphid populations. They can adapt to various habitats and make use of various aphid species associated with multiple host plants during their life cycle. Agricultural landscapes in China are composed of a mosaic of small fields with a diverse range of crops, and how ladybeetles make use of host plant diversity in such landscapes has rarely been documented. In this study, we examined the relationship between aphid densities and ladybeetle densities in two different settings: (i) on the majority of plant species (including crops, trees, and weeds) at a local field scale in 2013 and 2014, and (ii) in paired cotton and maize crop fields at a regional landscape scale in 2013. Overall, we found that aphid abundance determined predatory ladybeetle abundance at both the local field and landscape scales, and there was a positive correlation between aphid densities and ladybeetle densities. However, plant taxa had no significant influence on the predatory ladybeetle abundance at the local field scale. In addition, the effect of aphids on ladybeetles abundance was influenced by the crop type and growing season at the regional landscape scale. There was a significant positive correlation between aphids and ladybeetles populations on cotton only in July and August, whereas the correlation was significant for maize throughout the whole growing season. We also conducted an analysis of the stable carbon isotope ratios of the adult ladybeetles caught in cotton and maize fields (C3 and C4 crops, respectively) in a regional landscape-scale survey in 2013. The δ13Cvalue indicated that most prey aphids for ladybeetles originated from crops where aphids are abundant (cotton in June and July; both maize and cotton in August).These findings improved our understanding of the migration and dispersal of ladybeetles among different habitats and plant species and provided insight into the promotion of the regional conservation and pest control of natural enemies in northern China.

Landscape- and site-level responses of woody structure and ground flora to repeated prescribed fire in the Missouri Ozarks

2019 ◽  
Vol 49 (8) ◽  
pp. 1004-1014 ◽  
Author(s):  
Calvin J. Maginel ◽  
Benjamin O. Knapp ◽  
John M. Kabrick ◽  
Rose-Marie Muzika
Keyword(s):  
Species Richness ◽  
Prescribed Fire ◽  
Prescribed Burning ◽  
Spatial Scales ◽  
Basal Area ◽  
Fire Effects ◽  
Ground Flora ◽  
In Fire ◽  
Community Restoration ◽  
Site Types

Landscape-scale prescribed burning may be appealing for natural community restoration due to operational efficiency and possible heterogeneity in fire effects across broad spatial scales. We monitored plant community responses for >15 years with variable prescribed fire frequencies applied across a Missouri Ozarks landscape stratified into distinct ecological site types. Through the study period, burning had no effect on the overstory tree density or basal area. Midstory stem densities decreased rapidly in periodically burned units and more gradually with annual fire. Burning increased total ground flora cover and the cover of forbs, grasses, and legumes. The effect of burning on species richness differed among site types, with increased species richness through time on exposed slopes. There was no effect of prescribed burning on species richness on two of three protected slope site types, and annual burning decreased species richness in upland waterways. Among the site types, the upland waterways had the most species associated with pre-burn communities. We conclude that (i) burning consistently increased cover of ground layer vegetation across the landscape, while decreasing the midstory stem densities, and (ii) site type moderated ground flora richness response, with more pronounced effects of prescribed burning on exposed sites than on protected sites.

Consequences of various landscape-scale ecosystem management strategies and fire cycles on age-class structure and harvest in boreal forests

2004 ◽  
Vol 34 (2) ◽  
pp. 310-322 ◽  
Author(s):  
Andrew Fall ◽  
Marie-Josée Fortin ◽  
Daniel D Kneeshaw ◽  
Stephen H Yamasaki ◽  
Christian Messier ◽  
...  
Keyword(s):  
Forest Management ◽  
Ecosystem Management ◽  
Scale Effects ◽  
Management Strategies ◽  
Landscape Scale ◽  
Stand Age ◽  
Class Structure ◽  
Fire Cycle ◽  
Class Distribution ◽  
Age Class

At the landscape scale, one of the key indicators of sustainable forest management is the age-class distribution of stands, since it provides a coarse synopsis of habitat potential, structural complexity, and stand volume, and it is directly modified by timber extraction and wildfire. To explore the consequences of several landscape-scale boreal forest management strategies on age-class structure in the Mauricie region of Quebec, we used spatially explicit simulation modelling. Our study investigated three different harvesting strategies (the one currently practiced and two different strategies to maintain late seral stands) and interactions between fire and harvesting on stand age-class distribution. We found that the legacy of initial forested age structure and its spatial configuration can pose short- (<50 years) to medium-term (150–300 years) challenges to balancing wood supply and ecological objectives. Also, ongoing disturbance by fire, even at relatively long cycles in relation to historic levels, can further constrain the achievement of both timber and biodiversity goals. For example, when fire was combined with management, harvest shortfalls occurred in all scenarios with a fire cycle of 100 years and most scenarios with a fire cycle of 150 years. Even a fire cycle of 500 years led to a reduction in older forest when its maintenance was not a primary constraint. Our results highlight the need to consider the broad-scale effects of natural disturbance when developing ecosystem management policies and the importance of prioritizing objectives when planning for multiple resource use.

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