Burning for grassland pollination: recently burned patches promote plant flowering and insect pollinators

Grasslands are historically and evolutionarily associated with disturbances, such as fire, that drive biodiversity assembly patterns and biotic interactions. Disturbance suppression in fire-prone ecosystems usually leads to a decline in forb diversity and flowering due to biomass accumulation, which could jeopardize pollinator diversity. In this study, we investigated patterns and drivers of plant flowering and flower insect visitor communities in a chronosequence of patches from different time-since-fire categories in Southern Brazilian grasslands. Old-burnt patches (more than 2 years since fire) had taller vegetation, more biomass and grass cover than intermediate (about 1 year after fire) and freshly-burnt patches (less than 6 months since fire), which had increased bare soil cover. Forb flower abundance was much higher in freshly-burnt patches, directly predicted by the degree of habitat openness. Pollinator insects were then benefited by floral resource aggregation in freshly-burnt patches, increasing in abundance (bees and butterflies) and species richness (bees). Beetle communities were positively influenced by vegetation height. Furthermore, plant species flowering and bee species composition varied between freshly and old-burnt grasslands, with indicator species found for all recovery stages but mainly freshly-burnt patches. Altogether, these results indicate the importance of maintaining freshly-burnt patches in the grassland landscape: it helps to sustain flower diversity, pollination services, and flowering plant reproduction. Our findings support the idea that a mosaic of grasslands from different times-since-fire should be considered for grassland conservation.

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Vegetation height and cover fraction between 60° S and 60° N from ICESat GLAS data

Geoscientific Model Development ◽

10.5194/gmd-5-413-2012 ◽

2012 ◽

Vol 5 (2) ◽

pp. 413-432 ◽

Cited By ~ 69

Author(s):

S. O. Los ◽

J. A. B. Rosette ◽

N. Kljun ◽

P. R. J. North ◽

L. Chasmer ◽

...

Keyword(s):

Vegetation Cover ◽

Climate Models ◽

Soil Cover ◽

Bare Soil ◽

Ecological Models ◽

Tree Cover ◽

Data Sets ◽

Vegetation Height ◽

Height Estimates ◽

Global Vegetation

Abstract. We present new coarse resolution (0.5° × 0.5°) vegetation height and vegetation-cover fraction data sets between 60° S and 60° N for use in climate models and ecological models. The data sets are derived from 2003–2009 measurements collected by the Geoscience Laser Altimeter System (GLAS) on the Ice, Cloud and land Elevation Satellite (ICESat), the only LiDAR instrument that provides close to global coverage. Initial vegetation height is calculated from GLAS data using a development of the model of Rosette et al. (2008) with with further calibration on desert sites. Filters are developed to identify and eliminate spurious observations in the GLAS data, e.g. data that are affected by clouds, atmosphere and terrain and as such result in erroneous estimates of vegetation height or vegetation cover. Filtered GLAS vegetation height estimates are aggregated in histograms from 0 to 70 m in 0.5 m intervals for each 0.5° × 0.5°. The GLAS vegetation height product is evaluated in four ways. Firstly, the Vegetation height data and data filters are evaluated using aircraft LiDAR measurements of the same for ten sites in the Americas, Europe, and Australia. Application of filters to the GLAS vegetation height estimates increases the correlation with aircraft data from r = 0.33 to r = 0.78, decreases the root-mean-square error by a factor 3 to about 6 m (RMSE) or 4.5 m (68% error distribution) and decreases the bias from 5.7 m to −1.3 m. Secondly, the global aggregated GLAS vegetation height product is tested for sensitivity towards the choice of data quality filters; areas with frequent cloud cover and areas with steep terrain are the most sensitive to the choice of thresholds for the filters. The changes in height estimates by applying different filters are, for the main part, smaller than the overall uncertainty of 4.5–6 m established from the site measurements. Thirdly, the GLAS global vegetation height product is compared with a global vegetation height product typically used in a climate model, a recent global tree height product, and a vegetation greenness product and is shown to produce realistic estimates of vegetation height. Finally, the GLAS bare soil cover fraction is compared globally with the MODIS bare soil fraction (r = 0.65) and with bare soil cover fraction estimates derived from AVHRR NDVI data (r = 0.67); the GLAS tree-cover fraction is compared with the MODIS tree-cover fraction (r = 0.79). The evaluation indicates that filters applied to the GLAS data are conservative and eliminate a large proportion of spurious data, while only in a minority of cases at the cost of removing reliable data as well. The new GLAS vegetation height product appears more realistic than previous data sets used in climate models and ecological models and hence should significantly improve simulations that involve the land surface.

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Vegetation height products between 60° S and 60° N from ICESat GLAS data

Geoscientific Model Development Discussions ◽

10.5194/gmdd-4-2327-2011 ◽

2011 ◽

Vol 4 (3) ◽

pp. 2327-2363 ◽

Cited By ~ 7

Author(s):

S. O. Los ◽

J. A. B. Rosette ◽

N. Kljun ◽

P. R. J. North ◽

J. C. Suárez ◽

...

Keyword(s):

Vegetation Cover ◽

Land Surface ◽

Climate Models ◽

Soil Cover ◽

Bare Soil ◽

Ecological Models ◽

Tree Cover ◽

Data Sets ◽

Vegetation Height ◽

Global Vegetation

Abstract. We present a new method to obtain coarse resolution (0.5° × 0.5°) vegetation height and vegetation-cover fraction data sets between 60° S and 60° N for use in climate models and ecological models. The data sets are derived from the Geoscience Laser Altimeter System (GLAS) on the Ice, Cloud and land Elevation Satellite (ICESat), which is the only LiDAR instrument that provides close to global coverage when all data collected for 2003–2009 are combined. Filters are applied to the GLAS data to identify and eliminate spurious observations, e.g. data that are affected by clouds, atmosphere and terrain and as such result in erroneous estimates of vegetation height or vegetation cover. GLAS vegetation height estimates are aggregated in histograms from 0 to 70 m in 0.5 m intervals. The GLAS vegetation height product is evaluated in four ways. First, unfiltered and filtered individual GLAS vegetation height measurements are compared with aircraft LiDAR measurements of the same from seven sites in the Americas, Europe, and Australia. Application of filters increases the correlation with aircraft data from r = 0.36 to r = 0.67 and decreases the root-mean-square error by a factor 3. Second, the global aggregated GLAS vegetation height product is tested for sensitivity towards the choice of data quality filters; areas with frequent cloud cover and areas with steep terrain are the most sensitive to the choice of thresholds for the filters. Thirdly, the GLAS global vegetation height product is compared with two other global vegetation height products and is believed to produce more realistic characteristics: dominant vegetation height for tropical forests between 30 and 60 m versus 20 and 40 m in existing products. Finally, the GLAS bare soil cover fraction is compared globally with the MODIS bare soil fraction (r = 0.55) and with the FASIR bare soil cover fraction estimates (r = 0.58); the correlation between GLAS and MODIS tree-cover fraction was (r = 0.76). The evaluation indicates that filters applied to the GLAS data are conservative and eliminate a large proportion of spurious data, while only in a minority of cases at the cost of removing reliable data as well. The present GLAS vegetation height product appears more realistic than previous data sets used for input to climate models and ecological models and hence should significantly improve simulations that involve the land surface.

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Factors influencing the persistence of reindeer lichens (Cladonia subgenus Cladina) within frequent-fire environments of the Mid-Atlantic Coastal Plain, USA

Fire Ecology ◽

10.1186/s42408-019-0063-7 ◽

2020 ◽

Vol 16 (1) ◽

Cited By ~ 1

Author(s):

David G. Ray ◽

Gabriel D. Cahalan ◽

James C. Lendemer

Keyword(s):

Woody Debris ◽

Forest Health ◽

Bare Soil ◽

Atlantic Coastal Plain ◽

Restoration Management ◽

Terricolous Lichens ◽

Reindeer Lichens ◽

In Fire ◽

Atlantic Coastal ◽

Overstory Composition

Abstract Background Prescribed fire is increasingly used to accomplish management goals in fire-adapted systems, yet our understanding of effects on non-target organisms remains underdeveloped. Terricolous lichens in the genus Cladonia P. Browne, particularly cushion-forming reindeer lichens belonging to Cladonia subgenus Cladina Nyl., fit into this category, being characteristic of fire-adapted ecosystems, yet highly vulnerable to damage or consumption during burns. Moreover, inherently slow dispersal and growth rates raise questions about how to conserve these taxa in the context of fire-mediated restoration management. This research was undertaken to identify factors that contribute to Cladonia persistence within areas subject to repeated burning and involved tracking the fate of 228 spatially isolated individuals distributed across seven sites previously burned zero to two times. Site selection was determined by edaphic factors associated with a rare inland dune woodland community type known to support relatively high densities of Cladonia. Results Evaluated across all sites, the post-burn condition of Cladonia subtenuis (Abbayes) Mattick samples, categorized as intact (32%), fragmented (33%), or consumed (36%) individuals, approximated a uniform distribution. However, their status was highly variable at the different sites, where from 0 to 70% were assessed as intact and 11 to 60% consumed. Machine-learning statistical techniques were used to identify the factors most strongly associated with fire damage, drawing from variables describing the proximate fuel bed, growth substrate, and fire weather. The final descriptive model was dominated by variables characterizing the understory fuel matrix. Conclusions Areas with highly contiguous fuels dominated by pyrogenic pine needles were most likely to result in consumption of individual Cladonia, whereas those growing in areas with low fuel continuity or in areas dominated by hardwood litter were more likely to persist (intact or as fragments). Further, substrates including bare soil and moss mats afforded more protection than coarse woody debris or leaf litter in settings where fuels were both contiguous and highly flammable. Our findings describe the characteristics of within-site fire refugia, the abundance of which may be enhanced over time through restoration and maintenance treatments including thinning, promotion of mixed-species overstory composition, and periodic burning. Because lichens contribute to, and are considered reliable indicators of forest health, fire-based restoration management efforts will benefit from improved understanding of how these vulnerable organisms are able to persist.

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Agronomic performances of Pak Choi grown with different soil cover

Horticultura Brasileira ◽

10.1590/s0102-053620150000200020 ◽

2015 ◽

Vol 33 (2) ◽

pp. 261-266 ◽

Cited By ~ 1

Author(s):

Márcia M Echer ◽

Graciela M Dalastra ◽

Tiago L Hachmann ◽

Elcio S Klosowski ◽

Vandeir F Guimarães

Keyword(s):

Soil Cover ◽

Block Design ◽

Dry Weight ◽

Bare Soil ◽

Production Traits ◽

Pak Choi ◽

Randomized Block Design ◽

Black Plastic ◽

Growing Conditions ◽

Set Up

An important aspect in the cultivation of vegetables is the quality of the product to be marketed, free from dirt and damage and the practice of mulching could be an option, but there is scarse information. The aim of this study was to evaluate the influence of mulching on the production traits of three cultivars of Pak Choi. The experiment was set up during March to May 2013 using a split plot randomized block design, with four replications. Soil cover treatments (white agrotextile, black agrotextile, black plastic, silver plastic, tifton straw and bare soil) were arranged in the plots, and three cultivars of Pak Choi (Green Pak Choi, White Pak Choi and Chingensai Natsu Shomi) in subplots. Height and diameter of shoots, number of leaves, fresh weight of the head and petiole, base diameter, dry weight of stem, petiole, and leaf were evaluated thirty-five days after transplantation. The total dry weight and leaf area were measured, and then we estimated the yield. There was a significant effect of soil cover and cultivar. In general, the cover with synthetic materials showed higher values on production of Pak Choi. The cultivar White Pak Choi was better adapted to the growing conditions, with an average yield of 57.78 t/ha.

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Plant Origin and Other Attributes Impact Bee Forage Patterns in a Common Garden Study in Maine, United States; Part II

Environmental Entomology ◽

10.1093/ee/nvaa029 ◽

2020 ◽

Vol 49 (3) ◽

pp. 738-752 ◽

Cited By ~ 2

Author(s):

Alison C Dibble ◽

Francis A Drummond ◽

Lois Berg Stack

Keyword(s):

Native Plants ◽

Common Garden ◽

Flowering Plant ◽

Strong Response ◽

Late Flowering ◽

Flowering Duration ◽

Introduced Plants ◽

Visitation Rates ◽

Plant Taxon ◽

Floral Resource

Abstract In a common garden study in Maine from 2012 to 2015, we used two bee species (Apis mellifera L. and Bombus ternarius Say (1837)) and three field-recognizable bee categories (‘Most Bombus’, ‘Halictidae’, and ‘Other Bees’) plus an ‘All Bees’ data aggregation to compare 17 native and 68 introduced plant taxa. Data were from three 1-min timed periods per flowering plant taxon on a given day at a site. We observed 17,792 bees and found that their response varied by bee species or group. Using mixed models to analyze our data, we found that native bees had higher visitation rates on native plants, while A. mellifera visited both native and introduced plants. Most groups visited native late-flowering and native mid-late-flowering plants at higher rates. ‘All Bees’ were attracted to native perennials (vs annuals and shrubs) and to tall plants, both native and introduced; A. mellifera was attracted to introduced perennials, to introduced tall plants, and to lower-growing native plants. Asclepias tuberosa L. elicited a strong response from B. ternarius. In only two of six pairs of wild types and cultivars, bees visited wild types more. Plants with long bloom periods and with small, densely arranged white flowers attracted higher bee visitation than did other configurations (e.g., Origanum vulgare L., one of our most attractive taxa). A general linear model showed that linear combinations of flower density, floral resource height, flower corolla depth, and flowering duration explained significant variation in visitation rates for each of the different bee taxa groups.

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Floristic and structural patterns in South Brazilian coastal grasslands

Anais da Academia Brasileira de Ciências ◽

10.1590/0001-3765201520140555 ◽

2015 ◽

Vol 87 (4) ◽

pp. 2081-2090 ◽

Cited By ~ 4

Author(s):

LUCIANA S. MENEZES ◽

SANDRA C. MÜLLER ◽

GERHARD E. OVERBECK

Keyword(s):

Coastal Plain ◽

Management Practices ◽

Regional Scale ◽

Coastal Region ◽

Bare Soil ◽

Livestock Grazing ◽

Paspalum Notatum ◽

Southern Brazil ◽

Important Species ◽

Vegetation Height

ABSTRACT The natural vegetation of Southern Brazil's coastal region includes grasslands formations that are poorly considered in conservation policy, due to the lack of knowledge about these systems. This study reports results from a regional-scale survey of coastal grasslands vegetation along a 536 km gradient on southern Brazil. We sampled 16 sites along the coastal plain with 15 plots (1 m²) per site. All sites were grazed by cattle. We estimated plant species cover, vegetation height, percentage of bare soil, litter and manure, and classified species according to their growth forms. We found 221 species, 14 of them exotic and two threatened. The prostate grasses: Axonopus aff.affinis, Paspalum notatum and P. pumilumwere among the most important species. Prostrate graminoids species represented the most important vegetation cover, followed by cespitose grasses. Vegetation height, bare soil, litter and manure were similar among all areas, highlighting the homogeneity of sampling sites due to similar management. In comparison to other grasslands formations in Southern Brazil, the coastal grasslands presented rather low species richness. The presence of high values for bare soil at all sampling sites indicates the need to discuss management practices in the region, especially with regard to the intensity of livestock grazing.

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Short rotation forestry for land treatment of effluent: a lysimeter study

Soil Research ◽

10.1071/sr98067 ◽

1999 ◽

Vol 37 (5) ◽

pp. 983 ◽

Cited By ~ 7

Author(s):

J. K. F. Roygard ◽

N. S. Bolan ◽

B. E. Clothier ◽

S. R. Green ◽

R. E. H. Sims

Keyword(s):

Tree Species ◽

Root Zone ◽

Dairy Farm ◽

Biomass Accumulation ◽

Bare Soil ◽

Winter Period ◽

Evergreen Species ◽

Drinking Water Standard ◽

Short Rotation ◽

Land Treatment

Land treatment of wastewater using short rotation forestry (SRF) has potential as a sustainable method for disposal of dairy-farm euent. We compared 3 SRF species, 2 evergreen species of eucalypts (Eucalyptus nitens, E. saligna) and a deciduous willow (Salix kinuyanagi), in the land treatment of dairy-farm euent. The trees were grown in lysimeters (1 . 8 m diameter, 1 . 0 m depth), and a bare soil treatment was used as a control. The application of dairy-farm oxidation-pond euent totalled 218 g N/lysimeter (equivalent to 870 kg N/ha) over 2 irrigation seasons (December 1995–June 1996 and September 1996–April 1997). Euent was applied weekly in summer at a rate of 18 . 9 mm/week. No euent was applied during the winter period. The evapotranspiration (ET) rates of the trees, and the volumes and nitrogen contents of the leachates are compared for a winter period (4 weeks) and a summer period (5 weeks). The biomass accumulation and the uptake of nitrogen by the 3 tree species were also investigated. The SRF trees improved the renovation levels of dairy-farm euent and produced biomass suitable for energy conversion. Of the 3 tree species, only the S. kinuyanagi treatments maintained leachate nitrate concentrations below the New Zealand drinking water standard of 11 . 3 mg NO– 3 -N/L throughout both the winter and summer periods. The E. nitens treatment produced significantly more oven-dry biomass (19 . 1 kg/tree) than the E. saligna trees (9 . 7 kg/tree) (P = 0 . 05). The S. kinuyanagi treatment had intermediate production (13 . 3 kg/tree) and was not significantly different from the other 2 tree species (P = 0 . 05). The nutrient accumulation was not significantly different among the species (P = 0 . 05). S. kinuyanagi was considered the best overall performer for the land treatment of dairy-farm euent, based on the concentrations of leachate moving beyond the root-zone.

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The third dimension: How fire-related research can advance ecology and evolutionary biology

Ideas in Ecology and Evolution ◽

10.24908/iee.2020.13.4.c ◽

2020 ◽

Vol 13 ◽

Author(s):

Byron Lamont ◽

Tianhua He

Keyword(s):

Fire Ecology ◽

Evolutionary Biology ◽

Biotic Interactions ◽

Global Scale ◽

Ecological Processes ◽

Related Research ◽

Biological Phenomena ◽

Environmental Interactions ◽

Third Dimension ◽

In Fire

Most of the Earth’s vegetated surface is fireprone but the relevance of fire in understanding how nature works is not always recognized. We aim to show that, by adding the fire dimension to observations on biological phenomena, interpretations can be im-proved; how fire-related research can be used to answer ‘fundamental’ questions in ecology; and how theories/models developed for fireprone ecosystems can be applied to advancing disturbance ecology, biogeography and evolutionary biology more generally. We compiled lists from the world-wide web of the most highly cited papers in fire ecology, and examined papers that had been approached from multiple viewpoints, including fire. We show that great advances over the last 20 years have been made in our understanding of the pivotal role of fire as a driver of many ecological processes and a powerful selective agent/evolutionary trigger among biota. We document 21 sets of observations originally interpreted in the context of the two traditional dimensions, prevailing environment and biotic interactions, but can also be shown to have a strong, if not dominant, historical link to fire. We note that fire-related research is able to address 55 of the 100 questions considered ‘fundamental’ in ecology and that many have already received some attention in fireprone ecosystems. We show how theories/ models that had their origins in fireprone systems can be applied to other disturbance-prone systems and thus have wide application in ecology and evolutionary biology. Fire and other disturbances should be included as variables in research about possible critical environmental and biotic constraints controlling ecosystem function in general. Adding this third dimension to research endeavours greatly enriches our understanding of how nature works at the global scale in an era where ecosystems are changing rapidly and novel species-environmental interactions are emerging.

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Mulch Effects on Floral Resources and Fruit Production of Squash, and on Pollination and Nesting by Squash Bees

HortTechnology ◽

10.21273/horttech.24.5.535 ◽

2014 ◽

Vol 24 (5) ◽

pp. 535-545 ◽

Cited By ~ 2

Author(s):

Caitlin E. Splawski ◽

Emilie E. Regnier ◽

S. Kent Harrison ◽

Karen Goodell ◽

Mark A. Bennett ◽

...

Keyword(s):

Weed Control ◽

Bare Soil ◽

Fruit Production ◽

Floral Resources ◽

Pollinator Attraction ◽

Available Nitrogen ◽

Soil Temperatures ◽

Black Plastic ◽

Negative Impacts ◽

Floral Resource

Zucchini squash (Cucurbita pepo) has a high pollination demand, and the native, ground-nesting squash bee (Peponapis pruinosa) provides the majority of the crop’s pollination requirement in some environments. Squash bees nest directly in crop fields, and nests can be disturbed by tillage and other management operations. Mulches that use municipal waste materials may provide a weed control strategy for squash plantings that is more benign to squash bees than cultivation. Field and greenhouse studies were conducted in 2011 and 2012 to compare the effects of nontillage weed control methods including polyethylene black plastic, woodchips, shredded newspaper, a combination of shredded newspaper plus grass clippings (NP + grass), and bare soil (control) on soil characteristics, squash pollination and fruit production, and squash bee nesting. Woodchips, shredded newspaper, and NP + grass mulch decreased soil temperature, while soils beneath newspaper mulch retained more moisture. Unmarketable, misshapen fruit occurred more frequently in plastic than in the other mulch treatments. No measurable differences in floral resource production or crop pollination were found among treatments, suggesting that misshapen fruit resulted from high soil temperatures in black plastic plots rather than poor pollinator attraction. Squash bee nests were located within bare soil, newspaper, and NP + grass plots, indicating that these mulches did not prevent nesting. NP + grass mulch had a positive effect on plant growth and fruit production, possibly from an addition of plant-available nitrogen or the presence of preferable nesting ground. Shredded newspaper when combined with grass clippings performed as an effective mulch material that improved crop performance with no apparent negative impacts on squash bee nesting or on squash floral resources and pollination.

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Diversified Floral Resource Plantings Support Bee Communities after Apple Bloom in Commercial Orchards

Scientific Reports ◽

10.1038/s41598-019-52601-y ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Sarah Heller ◽

Neelendra K. Joshi ◽

Timothy Leslie ◽

Edwin G. Rajotte ◽

David J. Biddinger

Keyword(s):

Flowering Plant ◽

Apple Orchards ◽

Beneficial Arthropods ◽

Natural Habitats ◽

Additional Food ◽

Pollinator Species ◽

Tree Fruit ◽

Nesting Resources ◽

Floral Resource ◽

Bee Communities

AbstractNatural habitats, comprised of various flowering plant species, provide food and nesting resources for pollinator species and other beneficial arthropods. Loss of such habitats in agricultural regions and in other human-modified landscapes could be a factor in recent bee declines. Artificially established floral plantings may offset these losses. A multi-year, season-long field study was conducted to examine how wildflower plantings near commercial apple orchards influenced bee communities. We examined bee abundance, species richness, diversity, and species assemblages in both the floral plantings and adjoining apple orchards. We also examined bee community subsets, such as known tree fruit pollinators, rare pollinator species, and bees collected during apple bloom. During this study, a total of 138 species of bees were collected, which included 100 species in the floral plantings and 116 species in the apple orchards. Abundance of rare bee species was not significantly different between apple orchards and the floral plantings. During apple bloom, the known tree fruit pollinators were more frequently captured in the orchards than the floral plantings. However, after apple bloom, the abundance of known tree fruit pollinating bees increased significantly in the floral plantings, indicating potential for floral plantings to provide additional food and nesting resources when apple flowers are not available.

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