The Ability of Alfalfa (Medicago sativa) to Establish in a Seminatural Habitat under Different Seed Dispersal Times and Disturbance

Alfalfa is an important forage crop in North America, and it can also be found as a roadside weed in alfalfa-growing regions. Weediness and invasiveness are greatly facilitated by establishment ability, yet little is known about the ability of alfalfa to establish in competitive environments such as roadsides. The primary objective of this study was to estimate the degree of alfalfa establishment without managed cultivation under different seed-dispersal times and disturbance regimes. The study had a split-plot design with two main plots (spring and fall seed dispersal) and five subplots (mowing, soil disturbance, herbicide spray, seedbed, and undisturbed control). The study examined establishment, growth attributes, and reproductive output of alfalfa in response to these treatments. Alfalfa establishment in the undisturbed grass swards ranged between 0.5 and 9.7% (out of the total number of seeds dispersed) across the dispersal times. The density of alfalfa in fall-seeded plots was about 82% lower than in spring-seeded plots. Soil disturbance reduced the density of alfalfa to < 50% of the initial density. Generally, low plant densities were compensated over time by increased numbers of shoots and reproductive units (racemes and pods) per plant. Herbicide application (2,4-D + dicamba) effectively controlled all emerged alfalfa plants, but in some cases, seedling recruitment was observed in the years following herbicide application. Although mowing did not kill alfalfa plants, mowed plants did not produce mature seeds, and as such, mowing may be useful in restricting the reproductive success and population growth of alfalfa. Overall, it is evident that alfalfa is capable of establishing in competitive environments (such as roadside habitats) and rapidly recovering from moderate disturbances. The results of this study have implications for managing roadside alfalfa and for designing novel trait-confinement protocols for alfalfa.

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Effects of disturbance and rabbit grazing on seedling recruitment of six mesic grassland species

Seed Science Research ◽

10.1017/s0960258599000161 ◽

1999 ◽

Vol 9 (2) ◽

pp. 145-156 ◽

Cited By ~ 19

Author(s):

Grant R. Edwards ◽

Michael J. Crawley

Keyword(s):

Seedling Recruitment ◽

Plantago Lanceolata ◽

Plant Cover ◽

Seedling Emergence ◽

Soil Disturbance ◽

Seedling Mortality ◽

Grassland Species ◽

Rabbit Grazing ◽

Plant Densities ◽

Seed Sowing

AbstractSeeds of two grass (Arrhenatherum elatius and Festuca rubra), two herb (Plantago lanceolata and Rumex acetosa) and two legume (Lotus corniculatus and Trifolium repens) species were sown in summer 1995 at four densities (no seed, 1000, 10 000 and 50 000 seeds m−2) into an established rabbit-grazed grassland given factorial combinations of rabbit fencing (with and without fences) and soil disturbance (with and without cultivation). On plots where no seeds were sown, only the species with persistent seed banks (P. lanceolata, L. corniculatus and T. repens) showed enhanced seedling emergence in response to disturbance. In disturbed soil, seedling densities of all species increased with increasing density of sown seeds, the effects of which were still evident for plant cover 2 years after seed sowing. In undisturbed vegetation, A. elatius, F. rubra, P. lanceolata and R. acetosa showed increased seedling densities following seed sowing; but in each case, there was an upper asymptote to seedling recruitment, presumably due to microsite limitation. Rabbit grazing reduced seedling densities, with this reduction being more pronounced with disturbance than without. However, the effect of rabbit grazing did not persist for some species; seedling mortality of R. acetosa, P. lanceolata, L. corniculatus and T. repens was higher on plots without rabbit grazing, so that plant densities of these species in summer 1996 and plant cover in summer 1997 were greater on grazed plots. The results indicate interactions between soil disturbance, propagule availability and herbivory, rather than disturbance alone, will play an important role in controlling seedling recruitment and species habitat distributions in grasslands.

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Tracking Animal-Dispersed Seedlings Using 15N Xylem Injection Method

Frontiers in Plant Science ◽

10.3389/fpls.2021.582530 ◽

2021 ◽

Vol 12 ◽

Author(s):

Minghui Wang ◽

Sijie Yi ◽

Mengyao Ju ◽

Xianfeng Yi

Keyword(s):

Stable Isotopes ◽

Seed Germination ◽

Seed Dispersal ◽

Seedling Establishment ◽

Seedling Recruitment ◽

Nondestructive Method ◽

Seed Selection ◽

Injection Method ◽

Seed Eating ◽

Mature Seeds

Although various seed-marking methods have been developed for seed dispersal, it remains difficult to track the actual patterns of seed dispersal and seedling recruitment. Thus, new labeling methods that accurately track seedling establishment along with seed movement would help us better understand seed dispersal. Here, we developed a new nondestructive method using 15N xylem injection to track seed dispersal and seedling recruitment based on the enriched isotopic signals in the mature seeds. Our results first showed that xylem injection of 15N successfully enriched 15N both in the acorns and seedlings of Quercus variabilis. By marking acorns and seedlings with 15N stable isotopes, we successfully tracked seedlings established from acorns dispersed by seed-eating animals in the field. Our xylem 15N injection caused little alteration to seeds and showed no significant effects on seed selection by seed-eating animals as well as seed germination and seedling establishment, verifying the validity of the 15N xylem injection method to track seedling establishment. Our xylem 15N injection method is expected to be a powerful tool for tracking seed dispersal and seedling recruitment mediated by seed-eating animals in seed dispersal ecology.

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Dispersal ofAcaciaseeds by ungulates and ostriches in an African savanna

Journal of Tropical Ecology ◽

10.1017/s0266467400009548 ◽

1996 ◽

Vol 12 (3) ◽

pp. 345-356 ◽

Cited By ~ 50

Author(s):

Maxine F. Miller

Keyword(s):

South Africa ◽

Seed Dispersal ◽

Seedling Recruitment ◽

Seedling Survival ◽

Tree Crown ◽

African Savanna ◽

Large Herbivores ◽

Mammalian Herbivores ◽

Open Environments ◽

Presence And Absence

ABSTRACTThe dispersal of AfricanAcaciaseeds in the presence and absence of large mammalian herbivores and ostriches was assessed in a savanna ecosystem in South Africa. In the absence of large herbivores,A. tortilisandA. niloticapods were mainly dispersed in the shade, directly beneath the tree crown and seeds remained in pods for over 18 months. In the presence of large herbivores,A. tortilis, A. niloticaandA. karrooseeds were freed from pods and were dispersed into open, non-shaded habitats. Impala dispersed mostA. tortilisseeds (18,900 ha−1), giraffe mostA. niloticaseeds (1060 ha−1) and giraffe and kudu mostA. karrooseeds (452 and 448 ha−1, respectively). Seedling survival in dung in open environments may exceed that of seedlings in soil shaded beneath the tree crown. It appears that seed dispersal by large herbivores may be advantageous to future seedling recruitment.

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Spatiotemporal Patterns and Mechanisms of Chinese Tallowtree (Triadica sebifera) Spread along Edge Habitat in a Coastal Landscape, Mississippi, USA

Invasive Plant Science and Management ◽

10.1017/inp.2018.21 ◽

2018 ◽

Vol 11 (3) ◽

pp. 117-126 ◽

Cited By ~ 4

Author(s):

Zhaofei Fan ◽

Shaoyang Yang ◽

Xia Liu

Keyword(s):

Seed Dispersal ◽

Negative Binomial ◽

Seedling Recruitment ◽

Light Availability ◽

Spatiotemporal Patterns ◽

Tree Age ◽

Triadica Sebifera ◽

Factors Affecting ◽

Edge Habitat ◽

Dispersal Mechanism

AbstractChinese tallowtree [Triadica sebifera(L.) Small] has reached unprecedented prevalence in coastal landscapes in the Gulf of Mexico, especially along edge habitat with low competition and abundant resource (e.g., light) availability. This study investigated the spatiotemporal patterns and mechanisms ofT. sebiferaspread along roadways and fire lines.Triadica sebiferaindividuals and landscape and community features were surveyed in equally spaced, spatially mapped plots. AllT. sebiferaindividuals were felled to determine tree age and status (seed trees or non-seed bearing trees), andT. sebiferaseed and seedling (≤2 yr old) densities and community and landscape features (over- and understory conditions, distance to seed trees) were measured. A zero-inflated negative binomial model was used to evaluate factors affectingT. sebiferaseed dispersal and seedling recruitment contributing to the observed spatiotemporal patterns. Introduced into the Grand Bay National Wildlife Refuge around 30 yr ago,T. sebiferatrees distribute in clustered patterns along roadways and fire lines and exhibit an exponential growth in density. HighT. sebiferaseed and seedling densities mainly occurred in sites that are ≤250 m from seed trees or have sparse overstory and high understory grass/herb coverage. With respect to the avian seed dispersal mechanism, the spatiotemporal patterns ofT. sebiferaspread along roadways and fire lines could be simply characterized by using landscape and community features that influence avian behaviors, including distance to seed trees, overstory tree density, and ground grass/herb coverage.

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Seasonality of fruiting and food hoarding by rodents in neotropical forests: consequences for seed dispersal and seedling recruitment.

Seed dispersal and frugivory: ecology, evolution and conservation. Third International Symposium-Workshop on Frugivores and Seed Dispersal, São Pedro, Brazil, 6-11 August 2000 ◽

10.1079/9780851995250.0241 ◽

2009 ◽

pp. 241-256 ◽

Cited By ~ 5

Author(s):

P. M. Forget ◽

D. S. Hammond ◽

T. Milleron ◽

R. Thomas

Keyword(s):

Seed Dispersal ◽

Seedling Recruitment ◽

Food Hoarding ◽

Neotropical Forests

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SEED DISPERSAL, SEED PREDATION, AND SEEDLING RECRUITMENT OF A NEOTROPICAL MONTANE TREE

Ecological Monographs ◽

10.1890/0012-9615(2000)070[0331:sdspas]2.0.co;2 ◽

2000 ◽

Vol 70 (2) ◽

pp. 331-351 ◽

Cited By ~ 180

Author(s):

Daniel G. Wenny

Keyword(s):

Seed Dispersal ◽

Seed Predation ◽

Seedling Recruitment

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Seed Shadows of Northern Pigtailed Macaques within a Degraded Forest Fragment, Thailand

Forests ◽

10.3390/f11111184 ◽

2020 ◽

Vol 11 (11) ◽

pp. 1184

Author(s):

Eva Gazagne ◽

Jean-Luc Pitance ◽

Tommaso Savini ◽

Marie-Claude Huynen ◽

Pascal Poncin ◽

...

Keyword(s):

Seed Dispersal ◽

Seedling Recruitment ◽

Mechanistic Model ◽

Cheek Pouch ◽

Degraded Forest ◽

Forest Fragment ◽

Plantation Forests ◽

Maximum Range ◽

Seed Deposition ◽

Seed Shadows

Research Highlights: Frugivores able to disperse large seeds over large distances are indispensable for seedling recruitment, colonization and regeneration of tropical forests. Understanding their effectiveness as seed dispersal agents in degraded habitat is becoming a pressing issue because of escalating anthropogenic disturbance. Although of paramount importance in the matter, animal behaviour’s influence on seed shadows (i.e., seed deposition pattern of a plant population) is difficult to evaluate by direct observations. Background and Objectives: We illustrated a modeling approach of seed shadows incorporating field-collected data on a troop of northern pigtailed macaques (Macaca leonina) inhabiting a degraded forest fragment in Thailand, by implementing a mechanistic model of seed deposition with random components. Materials and Methods: We parameterized the mechanistic model of seed deposition with macaque feeding behavior (i.e., consumed fruit species, seed treatments), gut and cheek pouch retention time, location of feeding and sleeping sites, monthly photoperiod and movement patterns based on monthly native fruit availability using Hidden Markov models (HMM). Results: We found that northern pigtailed macaques dispersed at least 5.5% of the seeds into plantation forests, with a majority of medium- to large-seeded species across large distances (mean > 500 m, maximum range of 2300 m), promoting genetic mixing and colonization of plantation forests. Additionally, the macaques produced complementary seed shadows, with a sparse distribution of seeds spat out locally (mean >50 m, maximum range of 870 m) that probably ensures seedling recruitment of the immediate plant populations. Conclusions: Macaques’ large dispersal distance reliability is often underestimated and overlooked; however, their behavioral flexibility places them among the last remaining dispersers of large seeds in disturbed habitats. Our study shows that this taxon is likely to maintain significant seed dispersal services and promote forest regeneration in degraded forest fragments.

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