Habitat and Time Are More Important Predictors of Weed Seed Predation than Space on a Diversified Vegetable Farm in Maine, USA

Weed Science ◽  
2015 ◽  
Vol 63 (4) ◽  
pp. 916-927 ◽  
Author(s):  
Sonja K. Birthisel ◽  
Eric R. Gallandt ◽  
Randa Jabbour ◽  
Francis A. Drummond
Keyword(s):  
Seed Predation ◽  
Field Experiments ◽  
Riparian Forest ◽  
Ground Beetle ◽  
Habitat Type ◽  
Vegetative Cover ◽  
Weed Seed ◽  
Seed Predators ◽  
Vegetable Farm ◽  
Predation Rates

Postdispersal weed seed predation is a significant source of weed mortality in agroecosystems. The magnitude of seed predation, however, is variable. Understanding the relative importance of factors driving variability in seed predation rates will increase the potential utility of seed predation to farmers. We conducted landscape-scale field experiments to quantify and compare the effects of space, time of sampling, and habitat on weed seed predation. Seed predation assays, with and without vertebrate exclosures, measured seed predation rates at spatially explicit sample sites across 8.5 ha of crop and noncrop habitats on a diversified organic vegetable farm in Maine. Total and invertebrate seed predation averaged 8% and 3% d−1, respectively. Vertebrate seed predators detected by motion-sensing cameras included small mammals and birds. A ground beetle,Harpalus rufipes, was highly dominant in pitfall traps, comprising 66% of invertebrate seed predators captured within crop fields. Seed predation was randomly distributed in space. However, time of sampling and habitat were highly significant predictors of seed predation. Variance partitioning indicated that habitat factors explained more variation than did time of sampling. Total seed predation was greater in crop and riparian forest habitats than in mowed grass, meadow, or softwood forest. Generally, invertebrate seed predation was greatest at sites with an intermediate degree of vegetative cover, whereas habitat type was the chief biotic determinant of vertebrate seed predation rates. These results suggest cover cropping and wetland conservation as practices that may bolster seed predation rates.

Influence of tillage and crop residue on postdispersal predation of weed seeds

Weed Science ◽  
1999 ◽  
Vol 47 (2) ◽  
pp. 184-194 ◽  
Author(s):  
Heather E. Cromar ◽  
Stephen D. Murphy ◽  
Clarence J. Swanton
Keyword(s):  
Seed Predation ◽  
Crop Residue ◽  
Field Experiments ◽  
Biological Weed Control ◽  
Feeding Strategies ◽  
Natural Form ◽  
Common Lambsquarters ◽  
Seed Predators ◽  
No Till ◽  
Weed Seeds

Field experiments were conducted from 1995 to 1997 in southern Ontario to determine the influence of tillage and ground cover on the quantity of postdispersal seed predation of common lambsquarters and barnyardgrass. Ground-dwelling invertebrates were the dominant seed predators and were responsible for 80 to 90% of all seeds consumed. Predation was highest in no-till and moldboard-plowed environments (averaging 32% in both) and lowest in chisel-plowed environments (averaging 24%). This indicates that the relationship between the level of disturbance and predation is nonlinear and that other factors, such as the mobility of invertebrates and food availability, may also play important roles in determining the quantity of seed predation. In no-till, the type of crop residue also influenced the quantity of predation, with highest seed predation found in plots with corn residue (averaging 31%) and lowest in those with soybean and wheat residue (24 and 21%, respectively). It is apparent that there is an optimum combination of residue quantity and quality that maximizes the quantity of seed predation. Based on the experimental design used in this study, no feeding preference by seed predators was detected between common lambsquarters and barnyardgrass. Density-dependent feeding, however, was evident for both species. Most biological control efforts have centered around predators with specific feeding habits. We contend that invertebrates with opportunistic feeding strategies that feed on weed seeds may be the most significant broad spectrum and natural form of biological weed control affecting weed population dynamics. Populations of beneficial arthropods should be conserved, and management strategies that augment the size of their natural populations should be encouraged.

Annual Postdispersal Weed Seed Predation in Contrasting Field Environments

Weed Science ◽  
2013 ◽  
Vol 61 (2) ◽  
pp. 296-302 ◽  
Author(s):  
Adam S. Davis ◽  
Erin C. Taylor ◽  
Erin R. Haramoto ◽  
Karen A. Renner
Keyword(s):  
Seed Predation ◽  
Best Management Practices ◽  
Weed Management ◽  
Wheat Crop ◽  
Weed Seed ◽  
Giant Foxtail ◽  
Giant Ragweed ◽  
Ecological Weed Management ◽  
The Impact ◽  
Predation Rates

Interest in weed seed predation as an ecological weed management tactic has led to a growing number of investigations of agronomic and environmental effects on predation rates. Whereas the measurements in most of these studies have taken place at very short timescales, from days to weeks, measurements at longer timescales (from several months to a year) have greater relevance to the demographic impact of weed seed predation and potential contributions from this process to ecological weed management. Our aim was to quantify the impact of crop phase, within a corn–soybean–wheat crop sequence, on quarterly and annual seed predation rates of giant foxtail, giant ragweed, and velvetleaf. The study took place in areas of the northern U.S. Corn Belt contrasting in dominant land use: Savoy, IL (2005–2007), where corn and soybean production predominates, and East Lansing, MI (2005–2008), where crop production occurs within an old field/forest landscape matrix. Mean annual rates of weed seed predation by the combined action of invertebrate and vertebrate predators were 31 ± 1.6% for giant ragweed, 37 ± 1.4% for velvetleaf, and 53 ± 1.4% for giant foxtail. Crop phase had negligible effects upon long-term seed predation rates, accounting for less than 2% of observed variation. Weed species and site-year, in contrast, contributed 35% and 40%, respectively, of the variation in cumulative annual seed predation. These results are consistent with the spatial variability in best management practices seen at spatial scales greater than the county level: weed seed predation appears to be an inherently site-specific phenomenon. New developments in managing weed seed predation as an ecosystem service are therefore likely to have local recommendation domains or to be driven by stochastic annual variation related to weather or granivore demography.

scholarly journals Cover crop seed preference of four common weed seed predators

2019 ◽  
Vol 35 (5) ◽  
pp. 522-532 ◽  
Author(s):  
Connor Z. Youngerman ◽  
Antonio DiTommaso ◽  
John E. Losey ◽  
Matthew R. Ryan
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Ground Beetle ◽  
Ambrosia Artemisiifolia ◽  
Field Cricket ◽  
Hairy Vetch ◽  
Weed Seed ◽  
Crop Species ◽  
Seed Predators ◽  
Seed Preference

AbstractInvertebrate seed predators (ISPs) are an important component of agroecosystems that help regulate weed populations. Previous research has shown that ISPs' seed preference depends on the plant and ISP species. Although numerous studies have quantified weed seed losses from ISPs, limited research has been conducted on the potential for ISPs to consume cover crop seeds. Cover crops are sometimes broadcast seeded, and because seeds are left on the soil surface, they are susceptible to ISPs. We hypothesized that (1) ISPs will consume cover crop seeds to the same extent as weed seeds, (2) seed preference will vary by plant and ISP species, and (3) seed consumption will be influenced by seed morphology and nutritional characteristics. We conducted seed preference trials with four common ISPs [Pennsylvania dingy ground beetle (Harpalus pensylvanicus), common black ground beetle (Pterostichus melanarius), Allard's ground cricket (Allonemobius allardi) and fall field cricket (Gryllus pennsylvanicus)] in laboratory no choice and choice feeding assays. We compared seed predation of ten commonly used cover crop species [barley (Hordeum vulgare), annual ryegrass (Lolium multiflorum), pearl millet (Pennisetum glaucum), forage radish (Raphanus sativus), cereal rye (Secale cereale), white mustard (Sinapis alba), crimson clover (Trifolium incarnatum), red clover (Trifolium pratense), triticale (×Triticosecale) and hairy vetch (Vicia villosa)] and three weed species [velvetleaf (Abutilon theophrasti), common ragweed (Ambrosia artemisiifolia) and giant foxtail (Setaria faberi)]. All four ISPs readily consumed cover crop seeds (P < 0.05), but cover crops with hard seed coats and seed hulls such as hairy vetch and barley were less preferred. Our results suggest that farmers should select cover crop species that are avoided by ISPs if they plan on broadcasting the seed, such as with aerial interseeding.

Distribution of ecosystem services within oilseed rape fields: Effects of field defects on pest and weed seed predation rates

2020 ◽  
Vol 295 ◽  
pp. 106894 ◽  
Author(s):  
Ezequiel González ◽  
Miroslav Seidl ◽  
Tomáš Kadlec ◽  
Marco Ferrante ◽  
Michal Knapp
Keyword(s):  
Ecosystem Services ◽  
Oilseed Rape ◽  
Seed Predation ◽  
Weed Seed ◽  
Predation Rates ◽  
Field Defects

Does Forest Fragmentation and Selective Logging Affect Seed Predators and Seed Predation Rates of Prunus africana (Rosaceae)?

Biotropica ◽  
2007 ◽  
Vol 40 (2) ◽  
pp. 218-224 ◽  
Author(s):  
Nina Farwig ◽  
Bärbel Bleher ◽  
Sabine von der Gönna ◽  
Katrin Böhning-Gaese
Keyword(s):  
Forest Fragmentation ◽  
Seed Predation ◽  
Selective Logging ◽  
Prunus Africana ◽  
Seed Predators ◽  
Predation Rates

Experimental Substrate Affects Rate of Seed Removal in Assays of Invertebrate Seed Predation

2005 ◽  
Vol 19 (2) ◽  
pp. 481-485 ◽  
Author(s):  
Eric R. Gallandt
Keyword(s):  
Seed Predation ◽  
Field Experiments ◽  
Biological Weed Control ◽  
Invertebrate Predation ◽  
Weed Species ◽  
Control Field ◽  
Common Lambsquarters ◽  
Wild Mustard ◽  
Important Form ◽  
Predation Rates

Postdispersal seed predation by ground beetles may be an important form of biological weed control. Field experiments conducted in 2002 and 2003 determined invertebrate seed predators' ability to detect and remove seeds from different experimental substrates. Predation of wild mustard and common lambsquarters was greater when seeds were presented on sand compared with the two types of synthetic finishing pads; however, predation of velvetleaf, redroot pigweed, and hairy galinsoga was unaffected by substrate. Predation rates were not consistent across all experimental substrates. Estimates of invertebrate predation of common lambsquarters, yellow foxtail, and velvetleaf were greater for seeds offered on sand or synthetic pads than for seeds offered on soil or double-sided tape covered with soil. Although each substrate would be useful to estimate treatment effects on relative predation rates, the weed species by substrate interaction should be considered when comparing predation rates across experiments or when the absolute rate predation is of critical importance.

Depth of Seed Burial and Gender Influence Weed Seed Predation by Three Species of Ground Beetle (Coleoptera: Carabidae)

Weed Science ◽  
2015 ◽  
Vol 63 (4) ◽  
pp. 910-915 ◽  
Author(s):  
Sharavari S. Kulkarni ◽  
Lloyd M. Dosdall ◽  
John R. Spence ◽  
Christian J. Willenborg
Keyword(s):  
Seed Predation ◽  
Ground Beetle ◽  
Soil Surface ◽  
Ground Beetles ◽  
Burial Depth ◽  
Weed Seed ◽  
Seed Burial ◽  
Buried Seeds ◽  
Pterostichus Melanarius ◽  
And Gender

Ground beetles are postdispersal weed seed predators, yet their role in consuming buried seeds is not well studied. We conducted greenhouse experiments to investigate how seed burial affects consumption of weed seeds (volunteer canola) by adult ground beetles (Coleoptera: Carabidae). Seed burial depth influenced seed consumption rates as demonstrated by a significant interaction between seed burial depth, carabid species, and gender of the carabid tested. We observed higher seed consumption by females of all species, and greater consumption of seeds scattered on the soil surface compared with seeds buried at any depth. However, there was evidence of seed consumption at all depths. Adults ofPterostichus melanarius(Illiger) andHarpalus affinis(Schrank) consumed more buried seeds than did those ofAmara littoralisMannerheim. Agricultural practices, such as tillage, bury seeds at different depths and based on the results of this study, these practices may reduce seed consumption by carabids. Soil conservation practices that reduce tillage (conservation or zero tillage) will favor greater weed seed predation due, in part, to the high availability of seeds at the soil surface or at shallow soil depths.

Individual crop size increases predispersal predation by beetles in a tropical palm

2020 ◽  
pp. 1-4
Author(s):  
Morgana Maria Arcanjo Bruno ◽  
Klécia Gili Massi ◽  
Alexander V. Christianini ◽  
John du Vall Hay
Keyword(s):  
Seed Predation ◽  
Positive Influence ◽  
Reproductive Phenology ◽  
Individual Plant ◽  
Crop Size ◽  
Seed Predators ◽  
Plant Trait ◽  
Predispersal Seed Predation ◽  
Total Seed ◽  
Number Of Seeds

Abstract Predispersal seed predation is one of the main causes of seed mortality in plant populations, contributing to decreased plant recruitment. Seed loss has previously been found to be related to crop size. Thus, we examined the influence of individual crop size on predispersal seed predation by beetles in the palm Syagrus flexuosa in the Brazilian savanna. The study was carried out in three tropical woodland savanna sites, where we sampled the total seed crop of 46 fruiting palms and checked the presence of beetle larvae inside all seeds per plant. We observed predispersal seed predation of S. flexuosa from all sites and a high variation in the number of seeds preyed on per individual palm. Crop size had a positive influence on the number of seeds lost to predispersal seed predators. Variations in levels of predispersal seed predation may also be accounted for by the reproductive phenology of S. flexuosa. If fruits are not available at the same time, less resource is available for predators and therefore a high proportion of seeds may be preyed on. Thus, our study demonstrates that an individual plant trait, crop size, is an important predictor of beetle seed damage per palm and a driver of the number of seeds lost to predispersal seed predators.

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