Seed Removal Experiments on Desert Rodents: The Microhabitat by Moonlight Effect

We tested the influence of the aril on seed germination in controlled conditions and on the removal of M. champaca seeds in natural environment. Germination assays were kept at 25 ± 2 °C under continuous white light. Removal experiments were carried out in three "old" (39 to 62-years old) and three "new" (15-years old) eucalypt stands in Horto Florestal Navarro de Andrade, Rio Claro, SP. The results show that the aril inhibits the germination and the seeds exhibit a positively photoblastic reaction. We found higher seed removal in old eucalypt stands than the new ones, probably due to the higher density of rodents in the old stands. In the new stands, we found higher seed removal of arillated seeds by ants. Ants are important to remove the aril of seeds dropped by birds, not only enhancing seed germination but also preventing seed predation by rodents.

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Biotic processes in a coastal dunefield: An assessment of seed removal, with non-native seed removal experiments

Journal of Coastal Conservation ◽

10.1007/bf02742467 ◽

2001 ◽

Vol 7 (1) ◽

pp. 49-56 ◽

Cited By ~ 3

Author(s):

J. Guy Castley ◽

Graham I. H. Kerley ◽

Anton McLachlan

Keyword(s):

Seed Removal ◽

Native Seed ◽

Removal Experiments

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Seed type, habitat and time of day influence post-dispersal seed removal in temperate ecosystems

PeerJ ◽

10.7717/peerj.8769 ◽

2020 ◽

Vol 8 ◽

pp. e8769

Author(s):

Katja Wehner ◽

Lea Schäfer ◽

Nico Blüthgen ◽

Karsten Mody

Keyword(s):

Plant Species ◽

Removal Rate ◽

Experimental Studies ◽

Time Of Day ◽

Seed Removal ◽

Chelidonium Majus ◽

Natural Form ◽

Seed Dispersion ◽

Removal Experiments ◽

The Impact

Seed survival is of great importance for the performance of plant species and it is strongly affected by post-dispersal seed removal by either different animals such as granivorous species and secondary dispersers or abiotic conditions such as wind or water. The success of post-dispersal seed removal depends on seed specific traits including seed size, the presence of coats or elaiosomes, the mode of seed dispersion, and on the habitat in which seeds happen to arrive. In the present study we asked how seed traits (dehulled vs. intact; size; dispersal mode), habitat (forest vs. grassland), and time of day (night vs. day) influence post-dispersal seed removal of the four plant species Chelidonium majus, Lotus corniculatus, Tragopogon pratensis and Helianthus annuus. Seed removal experiments were performed in three regions in Hesse, Germany. The results showed different, inconsistent influences of time of day, depending on habitat and region, but consistent variation across seed types. C. majus and dehulled H. annuus seeds had the fastest removal rates. The impact of the habitat on post-dispersal seed removal was very low, only intact H. annuus seeds were removed at significantly higher rates in grasslands than in forests. Our study demonstrates consistent differences across seed types across different habitats and time: smaller seeds and those dispersed by animals had a faster removal rate. It further highlights that experimental studies need to consider seeds in their natural form to be most realistic.

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Secondary seed removal in a degraded forest habitat in Madagascar

Scientific Reports ◽

10.1038/s41598-021-96306-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Paula M. A. Fiedler ◽

Alice De Lapparent ◽

Jeremie Razafitsalama ◽

Justin Sanamo ◽

Kim J. E. Steffens ◽

...

Keyword(s):

Seed Dispersal ◽

Seed Predation ◽

Tree Species ◽

Natural Regeneration ◽

Forest Restoration ◽

Forest Degradation ◽

Degraded Forest ◽

Seed Removal ◽

Forest Habitat ◽

Removal Experiments

AbstractForest restoration is a prime goal within the 2021–2030 UN “Decade of Ecosystem Resoration”. As part of these activities, natural regeneration has to be promoted for biological as well as for economic reasons. For this, the processes of seed dispersal, seed predation and germination have to be understood in the original as well as in degraded vegetation formations. We used seed removal experiments to assess post-dispersal processes that influence recruitment along a gradient of forest degradation in Madagascar analyzing seeds of three animal dispersed tree species. The percentage of seeds consumed or dispersed, declined from forest (28.6%) to degraded forest (17.2%) to savanna (10.8%). Only three out of 1080 seeds were cached and remained intact during the 14-day experiment. All three seeds were cached in the forest habitat and none in the degraded forest and savanna. The low percentage of seeds removed may be due to the lack of endemic rodents caching seeds, as only introduced rats were recorded in the area. The species-poor fauna of potential secondary seed dispersers of the region and especially in the degraded areas might represent an obstacle for diverse regeneration in degraded regions of Madagascar.

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Post-Dispersal Seed Removal in a Large-Seeded Palm by Frugivore Mammals in Western Ecuador

Tropical Conservation Science ◽

10.1177/1940082920947041 ◽

2020 ◽

Vol 13 ◽

pp. 194008292094704

Author(s):

Sebastián Escobar ◽

Onja H. Razafindratsima ◽

Rommel Montúfar ◽

Henrik Balslev

Keyword(s):

Forest Cover ◽

Camera Trap ◽

Agroforestry System ◽

Seed Removal ◽

Mammal Species ◽

Removal Rates ◽

Removal Experiments ◽

Phytelephas Aequatorialis ◽

Disturbed Forest ◽

Dispersal Events

Post-dispersal seed removal by ground-foraging frugivores promotes secondary dispersal of large seeds, reducing seed predation and increasing recruitment and regeneration. We studied how habitat disturbance influences seed removal patterns in the large-seeded palm Phytelephas aequatorialis within three habitats forming a continuum of disturbance (agroforestry system, disturbed forest, and less-disturbed forest) using seed removal experiments and camera trapping. We tested whether seed removal rates, and both richness and composition of seed remover communities varied between the habitats. On average, 15 seeds were removed under each tree in the agroforestry system over seven days, which was significantly lower compared to the disturbed forest (18) and the less-disturbed forest (19). Eight mammal species were identified removing seeds in the three habitats. On average, one mammal species removed seeds at each station in the agroforestry system, which was significantly lower than the two species observed in the two forests. The composition of seed remover communities was significantly different between the three habitats. Our results suggest that the loss of forest cover in the agroforestry system has reduced the richness of seed removers, which subsequently caused decreased removal rates. Nevertheless, this habitat could still maintain effective seed dispersal events because spiny rats were important seed removers. Our camera trap data should be taken as preliminary because we could only identify less than half of the animals responsible for seed removal. This study highlights the importance of medium- and large-sized rodents for the removal and effective dispersal of large seeds in disturbed tropical habitats.

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Sewage sludge as a precursor of adsorbents/catalysts for environmental applications

Water Practice & Technology ◽

10.2166/wpt.2007.019 ◽

2007 ◽

Vol 2 (1) ◽

Author(s):

A. Ros ◽

C. Canals-Batlle ◽

M.A. Lillo-Ródenas ◽

E. Fuente ◽

M. A. Montes-Morán ◽

...

Keyword(s):

Sewage Sludge ◽

Room Temperature ◽

Waste Water Treatment ◽

Textural Properties ◽

Active Species ◽

Elemental Sulphur ◽

Gaseous Emissions ◽

Removal Experiments ◽

Catalytically Active

This paper focuses on the valorisation of solid residues obtained from the thermal treatment of sewage sludge. In particular, sewage sludge samples were collected from two waste water treatment plants (WWTPs) with different sludge line basic operations. After drying, sludges were heated up to 700 °C in appropriate ovens under diluted air (gasification) and inert (pyrolysis) atmospheres. The solids obtained, as well as the dried (raw) sludges, were characterised to determine their textural properties and chemical composition, including the speciation of their inorganic fraction. All the materials under study were employed as adsorbents/catalysts in H2S removal experiments at room temperature. It was found that, depending on the particular sludge characteristics, outstanding results can be achieved both in terms of retention capacities and selectivity. Some of the solids outperform commercially available sorbents specially designed for gaseous emissions control. In these adsorbents/catalysts, H2S is selectively oxidised to elemental sulphur most likely due to the presence of inorganic, catalytically active species. The role of the carbon-enriched part on these solids is also remarked.

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Effect of Barley Sowing Density on the Integrated Weed Management of Lolium rigidum (Annual Ryegrass) in Mediterranean Dryland: A Modeling Approach

Agronomy ◽

10.3390/agronomy11081565 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1565

Author(s):

María Belén D’Amico ◽

Guillermo R. Chantre ◽

Guillermo L. Calandrini ◽

José L. González-Andújar

Keyword(s):

Weed Management ◽

Life Cycles ◽

Integrated Weed Management ◽

Future Research ◽

Seed Removal ◽

Weed Infestation ◽

High Control ◽

Weed Dynamics ◽

The Impact

Population models are particularly helpful for understanding long-term changes in the weed dynamics associated with integrated weed management (IWM) strategies. IWM practices for controlling L. rigidum are of high importance, mainly due to its widespread resistance that precludes chemical control as a single management method. The objective of this contribution is to simulate different IWM scenarios with special emphasis on the impact of different levels of barley sowing densities on L. rigidum control. To this effect, a weed–crop population model for both L. rigidum and barley life cycles was developed. Our results point out: (i) the necessity of achieving high control efficiencies (>99%), (ii) that the increase of twice the standard sowing density of barley resulted in a reduction of 23.7% of the weed density, (iii) non-herbicide-based individual methods, such as delayed sowing and weed seed removal at harvest, proved to be inefficient for reducing drastically weed population, (iv) the implementation of at least three control tactics (seed removal, delay sowing and herbicides) is required for weed infestation eradication independently of the sowing rate, and (v) the effect of an increase in the sowing density is diluted as a more demanding weed control is reached. Future research should aim to disentangle the effect of different weed resistance levels on L. rigidum population dynamics and the required efficiencies for more sustainable IWM programs.

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Compromised Function of the Pancreatic Transcription Factor PDX1 in a Lineage of Desert Rodents

Journal of Mammalian Evolution ◽

10.1007/s10914-021-09544-x ◽

2021 ◽

Author(s):

Yichen Dai ◽

Sonia Trigueros ◽

Peter W. H. Holland

Keyword(s):

Transcription Factor ◽

Gene Conversion ◽

Cell Function ◽

Protein A ◽

Gene Promoter ◽

Homeodomain Protein ◽

Β Cell ◽

Desert Rodents ◽

Biased Gene Conversion ◽

Β Cell Function

AbstractGerbils are a subfamily of rodents living in arid regions of Asia and Africa. Recent studies have shown that several gerbil species have unusual amino acid changes in the PDX1 protein, a homeodomain transcription factor essential for pancreatic development and β-cell function. These changes were linked to strong GC-bias in the genome that may be caused by GC-biased gene conversion, and it has been hypothesized that this caused accumulation of deleterious changes. Here we use two approaches to examine if the unusual changes are adaptive or deleterious. First, we compare PDX1 protein sequences between 38 rodents to test for association with habitat. We show the PDX1 homeodomain is almost totally conserved in rodents, apart from gerbils, regardless of habitat. Second, we use ectopic gene overexpression and gene editing in cell culture to compare functional properties of PDX1 proteins. We show that the divergent gerbil PDX1 protein inefficiently binds an insulin gene promoter and ineffectively regulates insulin expression in response to high glucose in rat cells. The protein has, however, retained the ability to regulate some other β-cell genes. We suggest that during the evolution of gerbils, the selection-blind process of biased gene conversion pushed fixation of mutations adversely affecting function of a normally conserved homeodomain protein. We argue these changes were not entirely adaptive and may be associated with metabolic disorders in gerbil species on high carbohydrate diets. This unusual pattern of molecular evolution could have had a constraining effect on habitat and diet choice in the gerbil lineage.

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