Reduced plant fitness by pre-dispersal seed predation in the threatened plant species Cirsium decussatum

2018 ◽  
Vol 28 (2) ◽  
pp. 123-130 ◽  
Author(s):  
Alina Stachurska-Swakoń ◽  
Beata Barabasz-Krasny ◽  
Anna Klasa ◽  
Andrzej Palaczyk
Keyword(s):  
Plant Species ◽  
Seed Predation ◽  
Plant Traits ◽  
Plant Fitness ◽  
Plant Population Dynamics ◽  
Selective Force ◽  
Seed Predators ◽  
Threatened Plant Species ◽  
Taxonomic Groups ◽  
Oviposition Sites

AbstractSeed predation has been suggested to play a crucial role in plant population dynamics and could act as a strong selective force in the evolution of plant traits such as plant phenology, size and number of flowers. The loss of seeds could be particularly threatening for population maintenance of rare plant species. We investigated the influence of seed predators on plant fitness of the rare monocarpic thistle Cirsium decussatum. We tested the following hypotheses: (1) pre-dispersal seed predators reduce the number of dispersed propagules; (2) seed predators select larger inflorescences as oviposition sites; (3) the size of the capitulum is correlated with seed productivity; and (4) seed predators compete for the oviposition sites. We identified ten insect taxa from different taxonomic groups in the capitula of C. decussatum. Terellia longicauda larvae (Diptera: Tephritidae) were the most common. The presence of the flies’ larvae was positively correlated with the predation level in the capitula. Females of T. longicauda selected larger inflorescences for laying eggs that may increase offspring fitness as larger inflorescences promise more food resources. We could not prove the presence of competition between insect species inhabiting the capitula. Our data suggest, however, that T. longicauda, a specialized seminophagous dipteran, is one of the factors that negatively influence the fitness of threatened C. decussatum, lowering significantly the seed pool. Terellia longicauda potentially acts as a strong selective force in the evolution of C. decussatum inflorescence size.

scholarly journals A new hypothesis for the importance of seed dispersal in time

2018 ◽  
pp. 1795-1803
Author(s):  
Adriana Guzmán ◽  
Pablo R. Stevenson
Keyword(s):  
Seed Dispersal ◽  
Plant Species ◽  
Seed Predation ◽  
Survival Rates ◽  
Species Dispersal ◽  
Future Studies ◽  
Seed Predators ◽  
Colombian Amazon ◽  
New Hypothesis ◽  
Escape Hypothesis

Most studies on seed dispersal in time have focused on seed dormancy and the physiological triggers for germination. However, seed dispersed by animals with low metabolic and moving rates, and long gutpassage times such as terrestrial turtles, could be considered another type of dispersal in time. This study tests the hypothesis that seeds dispersed in time may lower predation rates. We predicted that seeds deposited below parent trees after fruiting fall has finished is advantageous to minimize seed predators and should show higher survival rates. Four Amazonian plant species, Dicranostyles ampla, Oenocarpus bataua, Guatteria atabapensis and Ocotea floribunda, were tested for seed survival probabilities in two periods: during fruiting and 10-21 days after fruiting. Experiments were carried out in two biological stations located in the Colombian Amazon (Caparú and Zafire Biological Stations). Seed predation was high and mainly caused by non-vertebrates. Out of the four plant species tested, only Guatteria atabapensis supported the time escape hypothesis. For this species, seed predation by vertebrates after the fruiting period increased (from 4.1% to 9.2%) while seed predation by nonvertebrates decreased (from 54.0% to 40.2%). in contrast, seed predation by vertebrates and by non-vertebrates after the fruiting period in D. ampla increased (from 7.9% to 22.8% and from 40.4% to 50.6%, respectively), suggesting predator satiation. Results suggest that for some species dispersal in time could be advantageous to avoid some type of seed predators. Escape in time could be an additional dimension in which seeds may reach adequate sites for recruitment. Thus, future studies should be address to better understand the survival advantages given by an endozoochory time-dispersal process.

Partial predispersal seed predation in Lotus corniculatus L. (Fabaceae)

1996 ◽  
Vol 6 (2) ◽  
pp. 65-69 ◽  
Author(s):  
Jeff Ollerton ◽  
Andrew Lack
Keyword(s):  
Population Dynamics ◽  
Seed Predation ◽  
Plant Traits ◽  
Lotus Corniculatus ◽  
Individual Plant ◽  
Ecological Significance ◽  
Plant Population Dynamics ◽  
Seedling Vigour ◽  
Seed Predator ◽  
Predispersal Seed Predation

AbstractPredispersal seed predation may have implications for plant population dynamics and the evolution of plant traits, but assessing the level of seed predation for an individual plant is not always straightforward. Seeds of Lotus corniculatus (Fabaceae) are often only partially eaten by a weevil seed predator, Apion loti. Samples of these seeds were tested for viability and subsequent seedling vigour. A large proportion of these damaged seeds were viable, and the resulting seedlings almost as vigorous as those from undamaged seeds. The ubiquity of these findings, and their ecological significance, is discussed.

scholarly journals Seed predation under high seed density condition: the palm Euterpe edulis in the Brazilian Atlantic Forest

2004 ◽  
Vol 20 (4) ◽  
pp. 471-474 ◽  
Author(s):  
Christiane von Allmen ◽  
L. Patricia C. Morellato ◽  
Marco A. Pizo
Keyword(s):  
Plant Species ◽  
Seed Predation ◽  
High Density ◽  
Seed Density ◽  
Brazilian Atlantic Forest ◽  
Density Condition ◽  
Seed Predators ◽  
Euterpe Edulis ◽  
Population Scale ◽  
Fruiting Plant

Over recent decades, studies on post-dispersal seed predation have revealed some general patterns despite dealing with a highly variable phenomenon (reviews in Crawley 1993, Hulme 1998). Most of these studies, however, were carried out with plant species whose population density range from low to moderately high (Hulme 1998). Only rarely has seed predation been studied in very dense stands of a given plant species (Schupp 1988a, b, 1992). In such a situation, seed predators might respond to the local availability of seeds in a manner that differs from their response under conditions of low seed density. For instance, a high density of seeds beneath a fruiting plant may attract seed predators, causing a positive correlation between predation and seed density (Janzen 1970). Schupp (1992), however, noted that at a population scale, a high density of seeds could satiate predators, resulting in a negative correlation between predation and seed density (see also Burkey 1994).

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.

Are listed threatened plant species actually at risk?

2002 ◽  
Vol 50 (1) ◽  
pp. 1 ◽  
Author(s):  
Mark A. Burgman
Keyword(s):  
Plant Species ◽  
Threatened Species ◽  
Feedback Loop ◽  
Conservation Status ◽  
The State ◽  
Scarce Resources ◽  
Threatened Plant ◽  
Threatened Plant Species ◽  
Legal Mandates ◽  
State Of The Environment

Despite the fact that the most changes in lists of threatened species reflect changes in knowledge rather than changes in conservation status, the lists continue to provide social and legal mandates for conservation; they are used to report on the state of the environment and to guide the allocation of scarce resources. There is a substantial under-representation of non-vascular species in threatened plant lists, reflected in an absence of documented extinctions among fungi and algae. Turnover in the composition of extinct flora lists in Australia suggests that the lists of threatened species may not be sufficiently reliable to form the basis for reporting on the state of the environment. They are of limited use in distinguishing between levels of threat and may not be a reliable guide for the allocation of scarce conservation resources among plant species. Systems for listing threatened species create a feedback loop, responsive to the subjective preferences of scientists, largely unresponsive to underlying true threats, self-perpetuating and accentuating bias with each iteration. Other tools, including formal decision approaches and the acquisition of new kinds of data, are needed to fill the roles.

Two new Banksia species from pleistocene sediments in western Tasmania

1991 ◽  
Vol 4 (3) ◽  
pp. 499 ◽  
Author(s):  
GI Jordan ◽  
RS Hill
Keyword(s):  
Plant Species ◽  
Late Pleistocene ◽  
Environmental Changes ◽  
Middle Pleistocene ◽  
Extinct Species ◽  
The Third ◽  
Taxonomic Groups

Subtribe Banksiinae of the Proteaceae was diverse in Tasmania in the early and middle Tertiary, but is now restricted to two species, Banksia marginata and B. serrata. Rapid and extreme environmental changes during the Pleistocene are likely causes of the extinction of some Banksia species in Tasmania. Such extinctions may have been common in many taxonomic groups. The leaves and infructescences of Banksia kingii Jordan & Hill, sp. nov. are described from late Pleistocene sediments. This is the most recent macrofossil record of a now extinct species in Tasmania. Banksia kingii is related to the extant B. saxicola. Banksia strahanensis Jordan & Hill, sp. nov. (known only from a leaf and leaf fragments and related to B. spinulosa) is described from Early to Middle Pleistocene sediments in Tasmania. This represents the third Pleistocene macrofossil record of a plant species which is now extinct in Tasmania.

Using summed individual species models and state-of-the-art modelling techniques to identify threatened plant species hotspots

2009 ◽  
Vol 142 (11) ◽  
pp. 2501-2509 ◽  
Author(s):  
Miia Parviainen ◽  
Mathieu Marmion ◽  
Miska Luoto ◽  
Wilfried Thuiller ◽  
Risto K. Heikkinen
Keyword(s):  
Plant Species ◽  
State Of The Art ◽  
Individual Species ◽  
Threatened Plant ◽  
Threatened Plant Species ◽  
Modelling Techniques
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