Editorial: Seed Science and Technology. Volume 49 Issue 3 (2021)

This issue of Seed Science and Technology is a good reflection of the wide scope of the field of study. Species of interest include major cultivated crops as well as wild and native species. Likewise, research topics span a wide array of subjects relevant to those interested in basic seed biology, production, testing, ecology, conservation and biodiversity. Understanding basic mechanisms of seed dormancy and germination remains a major topic of interest. Seed quality and its attributes are also of particular interest, as evidenced by research articles on seed vigour, health, genetic purity and physical characterisation.

Length-Weight Relationship, Condition Factor and Feeding Habit of Fishes from Mangrove of Santubong Estuary, Sarawak, Malaysia

Length-weight relationship (LWR), condition factor (K) and feeding habits of Coilia dussumieri, Nemapteryx nenga and Nibea soldado from Santubong Estuary, Sarawak, Malaysia were reported in the present study. The sampling was conducted during the non-monsoon season and monsoon season from April to November 2017 at Buntal, Penambir and Demak rivers using three-layered gillnets. A total of 182 fish samples were caught and measured for the total length and body weight. Then, the data were analysed by the equations for LWR and K. The feeding behaviour analysis was carried out using Relative Gut Index (RGI) and Frequency of Food Occurrence method. The log-transformed regression showed that most of the fishes exhibited negative allometric. K showed a significant difference between seasons. The RGI values of the fishes showed that they were carnivorous. The highest frequency of food occurrence in both seasons was gastropods (94-95 %) and the food items were found to be more variable during monsoon season (gastropods insect, worms, fish, asteroidea, phytoplankton and bivalve). The b value is an exponent to measure the growth pattern of fish and in this study, the b values were in the expected range of 2.5-3.5 and not affected by seasonal variation. The K values suggesting that most of the species were surviving well in the river and was influenced by seasonal change. The RGI and frequency of food occurrence showed that all fish in this study species were carnivorous with more variability in food was observed during the monsoon season. The data of this study are important for a sustainable fisheries management in this area.

Vocal Communication Within a Forest Bird Community

<p><b>This thesis takes a community approach to investigate the acoustics of forest birds in Zealandia sanctuary, Wellington. Initially, the annual changes in vocalisation output of 16 study species and their possible effect on bird conspicuousness were described. Environmental factors that may shape these avian vocalisations were addressed though invoking two key hypotheses, the acoustic adaptation hypothesis, and the acoustic niche hypothesis. In addition, the songs of selected species are investigated: the role of song harmonics in the native North Island saddleback, Philesturnus rufusater, and their role in ranging, change in song dialect through time and space in the introduced song thrush, Turdus philomelos, and temporal change in the song of the native grey warbler, Greygone igata. Vocal activity of the study species varied seasonally, affecting their detectability in bird counts. Some species were mostly first heard rather than seen and viceversa. The results lend support to the acoustic niche hypothesis in that vocalisations within the forest bird community appear to have evolved towards divergence, with native species’ vocalisations being more dispersed within the community acoustic space than those of the introduced species. However, all species concentrated their energy within relatively narrow frequency bands, supporting the predictions of the acoustic adaptation hypothesis. Adaptation to different transmission properties associated with different singing elevations or physiological parameters such as body weight may have an effect on shaping such bird vocalisations.</b></p> <p>Forests provide a complex acoustic space for sound transmission and a “sound window” may not be a constant property of a given forest. The study revealed that a prominent sound window persists in the lower frequency range that is less affected by habitat. Some high frequencies may have similar average attenuation values to those of low frequency, however, with greater fluctuation in attenuation. Ground effect is a further factor in determining how well different frequency ranges transmit and birds may use acoustic characteristics of their habitat to enhance their signal.</p> <p>Harmonics in North Island saddleback chatter song were found to play a potential role in ranging (estimating the distance of signaller), for playback songs with more relative energy within higher harmonics were evidently perceived as coming from a nearby individual.</p> <p>The repertoire size of the song thrush population studied in Zealandia has apparently evolved to become larger and more varied than the source population of song thrushes in the UK, with more syllables delivered with less repetition than the UK song recordings examined.</p> <p>Over a period of 7 years, syllables in grey warbler song have shifted to a higher frequency, but there was no difference in the temporal structure of the song. Habitat effect, competition on the acoustic signal from reintroduced birds and ambient noise level are considered as possible casual factors.</p>

Vocal Communication Within a Forest Bird Community

<p><b>This thesis takes a community approach to investigate the acoustics of forest birds in Zealandia sanctuary, Wellington. Initially, the annual changes in vocalisation output of 16 study species and their possible effect on bird conspicuousness were described. Environmental factors that may shape these avian vocalisations were addressed though invoking two key hypotheses, the acoustic adaptation hypothesis, and the acoustic niche hypothesis. In addition, the songs of selected species are investigated: the role of song harmonics in the native North Island saddleback, Philesturnus rufusater, and their role in ranging, change in song dialect through time and space in the introduced song thrush, Turdus philomelos, and temporal change in the song of the native grey warbler, Greygone igata. Vocal activity of the study species varied seasonally, affecting their detectability in bird counts. Some species were mostly first heard rather than seen and viceversa. The results lend support to the acoustic niche hypothesis in that vocalisations within the forest bird community appear to have evolved towards divergence, with native species’ vocalisations being more dispersed within the community acoustic space than those of the introduced species. However, all species concentrated their energy within relatively narrow frequency bands, supporting the predictions of the acoustic adaptation hypothesis. Adaptation to different transmission properties associated with different singing elevations or physiological parameters such as body weight may have an effect on shaping such bird vocalisations.</b></p> <p>Forests provide a complex acoustic space for sound transmission and a “sound window” may not be a constant property of a given forest. The study revealed that a prominent sound window persists in the lower frequency range that is less affected by habitat. Some high frequencies may have similar average attenuation values to those of low frequency, however, with greater fluctuation in attenuation. Ground effect is a further factor in determining how well different frequency ranges transmit and birds may use acoustic characteristics of their habitat to enhance their signal.</p> <p>Harmonics in North Island saddleback chatter song were found to play a potential role in ranging (estimating the distance of signaller), for playback songs with more relative energy within higher harmonics were evidently perceived as coming from a nearby individual.</p> <p>The repertoire size of the song thrush population studied in Zealandia has apparently evolved to become larger and more varied than the source population of song thrushes in the UK, with more syllables delivered with less repetition than the UK song recordings examined.</p> <p>Over a period of 7 years, syllables in grey warbler song have shifted to a higher frequency, but there was no difference in the temporal structure of the song. Habitat effect, competition on the acoustic signal from reintroduced birds and ambient noise level are considered as possible casual factors.</p>

Cross-species bamboo grading based on flexural properties

This experiment studied five species of bamboo culms [e.g. B. vulgaris (ampel), D. asper (betung), G. apus (tali), G. atroviolacea (hitam), and G. pseudoarundinaceae (andong)], then analyzed the possibility to develop cross-species bamboo structural grading (both strength and capacity grading) models by mean of dummy variable regression. Since the regression analysis resulted the significantly different coefficient values of the dummy variables, any coincided trendline did not found, but some parallel ones were obtained. The non-coincided but parallel trendlines indicated that a linear equation can estimate the average value of the grade determining property (GDP) of cross-species bamboo structural grading, while the constants must be added to consider the species influence. Meanwhile the non-parallel trendlines indicated that the different linear equation must be applied for every bamboo species. The crossspecies bamboo structural grading could not reliably justify in this study. Species have a strong influence on bamboo grading. Therefore, the authors suggest considering the species identification in the bamboo structural grading.

Metabarcoding insights into the diet and trophic diversity of six declining farmland birds

Knowledge of feeding ecology of declining species, such as farmland birds, is essential to address their conservation requirements, especially when their habitats are suffering important reductions of trophic resources. In this study, we apply a metabarcoding approach to describe the diet composition of six of the most significant farmland birds inhabiting European cereal pseudo-steppes: little bustard, great bustard, pin-tailed sandgrouse, black-bellied sandgrouse, red-legged partridge, and common quail. We further studied seasonal diet variations (autumn to spring) in all species but the common quail, whose diet was studied during spring and summer. We show that study species´ diets mostly consisted of plants, although in the case of little bustard and great bustard arthropods are also highly relevant. Among arthropods, we found high proportions of thrips, arachnids, and springtails, which were previously unreported in their diet, and some taxa that could be used as antiparasitic food. Moreover, we report that little bustard’s diet is the least rich of that of all studied species, and that diet of all these species is less diverse in winter than in autumn and spring. Diet composition of these declining species supports the importance of natural and semi-natural vegetation and landscape mosaics that can provide a wide variety of arthropods, plants, and seeds all year-round.

Argentinian odonates (dragonflies and damselflies): current and future distribution and discussion of their conservation

In terms of conservation, Argentinian odonates have not been assessed using a quantitative approach. One way to achieve this is by modelling their distribution to gather the extent of occurrence. Thus, we modelled the current and future (projected year, 2050) potential distribution of 44 odonate species that occur in Argentina as well as in neighboring countries. Our models of current times indicate a fairly wide distribution for most species but one exception is relevant for conservation purposes: Lestes dichrostigma has less than 30,000 km2 and falls in the ‘Near Threatened’ category according to the IUCN Red List. Another seven species have less than or close to 100,000 km2: Elasmothemis cannacrioides, Erythemis credula, E. paraguayensis, Heteragrion angustipenne, H. inca, Lestes forficula, and Mecistogaster linearis. Future distribution estimates suggest that: a) 12 species will lose or gain around 10%, four species will increase their distribution beyond 10% (up to 2,346%), and 28 species will lose more than 10% (up to 99%). Although current protected areas embrace most odonate species in Argentina, it is still premature to conclude whether this situation will remain in the future given the physiological tolerance and dispersal abilities of the study species among other drivers of distribution.

IgMAT: immunoglobulin sequence multi-species annotation tool for any species including those with incomplete antibody annotation or unusual characteristics

The advent and continual improvement of high-throughput sequencing technologies has made immunoglobulin repertoire sequencing accessible and informative regardless of study species. However, to fully map changes in polyclonal dynamics, precise annotation of these constantly rearranging genes is pivotal. For this reason, data agnostic tools able to learn from presented data are required. Most sequence annotation tools are designed primarily for use with human and mouse antibody sequences which use databases with fixed species lists, applying very specific assumptions which select against unique structural characteristics. We present IgMAT, which utilises a reduced amino acid alphabet, incorporates multiple HMM alignments into a single consensus and enables the incorporation of user defined databases to better represent their species of interest.Availability and implementationIgMAT has been developed as a python module, and is available on GitHub (https://github.com/TPI-Immunogenetics/igmat) for download under GPLv3 license.Supplementary informationModel Breakdowns

Radial variations in wood density, and their implications for above-ground biomass estimations, in a tropical high-andean forest

Wood density (WD) is a central trait to explain tree functioning, and is also an important predic­tor of tree above-ground biomass (AGB). Therefore, radial trends in WD (i.e., from pith to bark) may have important implications in understanding tree life-history variations, as well as in forest biomass and carbon estimations. The occurrence of these radial trends in WD is thought to vary among forests, particularly with canopy openness and stratification. Yet, most of the studies on this topic in tropical forests have been conducted on lowland closed-canopy forests, while very little is known about the prevalence and magnitude of these trends among trees from open-canopy forests, such as high-mountain forests. I examined radial gradients in WD and explored their implications for AGB estimations. Radial wood cores were taken with increment borers from 69 trees belonging to 18 species from a high-An­dean forest. Each wood core was cut every 1-cm, and WD was measured for every 1-cm segment. Errors in AGB estimations that resulted from not considering radial trends in WD were estimated for each tree and species. Eight out of eighteen species had significant radial trends in WD. Among these species, two species showed decreases of WD towards the bark, one species showed increments of WD from pith to bark, and five species showed U-shaped gradients (i.e., high WD near the pith and bark, and relatively low WD at inter­mediate diameters). The prevalence of U-shaped radial trends in WD may be related to the relatively open and less stratified canopy of the study forest. Not taking into account radial trends in WD led in general to under-estimations of AGB (averaging −7.66 % when using mean WD, and −5.56 % for outer WD) in most of the study species, suggesting that tropical high-Andean forests may possibly store more biomass carbon than has been previously estimated. These findings are important to expand our knowledge on wood allocation patterns during tree ontogeny, and also to improve the accuracy of biomass and carbon estimations in tropical high-Andean forests.