Litter Traits Research Articles

Patterns of decomposition and functional traits for flower and leaf litter in tropical woody species.

The variation within and across species has afterlife effects on carbon and nutrient cycling through the alteration of litter decomposability. However, the focus on leaves may not reflect a whole-plant economic spectrum of strategies. Here, we assessed the patterns and predictors of flower and leaf-litter decomposition at the intra- (i.e., flowers and leaves of the same species) and inter-specific (i.e., flowers and leaves from different species) levels for 29 tropical woody species in northeast Brazil. We evaluated nine functional litter traits, including structural and chemical traits. Flower litter decomposed, on average, three times faster than leaf litter (11.9% and 39.4% mass remaining, respectively) and exhibited higher water-holding capacity (WHC), leaching (LEA), and N, P, and K content. Otherwise, leaf litter showed higher density (DEN) and Ca, Mg, and Na content. The average relative differences in decomposition rate and functional traits between flower and leaf litter did not differ at both intra- and inter-specific levels. The predictors of decomposition were mostly similar, explaining 39% and 37% of flower and leaf litter, respectively. Leaching, P, Ca, Mg, and Na predict both flower and leaf-litter decomposition. However, WHC exclusively predicted flower-litter decomposition, and DEN, N, and K exclusively predicted leaf-litter decomposition. The observed differences in decomposition rate and functional traits between flower and leaf litter indicate that the afterlife effects differ between these plant organs and leverage the role of flower litter and its secondary consequences to nutrient and carbon cycling on ecosystems.

Genome-Wide Association Study of Reproductive Traits in Large White Pigs.

(1) Background: Reproductive performance is crucial for the pork industry's success. The Large White pig is central to this, yet the genetic factors influencing its reproductive traits are not well understood, highlighting the need for further research. (2) Methods: This study utilized Genome-Wide Association Studies to explore the genetic basis of reproductive traits in the Large White pig. We collected data from 2237 Large White sows across four breeding herds in southern China, focusing on eight reproductive traits. Statistical analyses included principal component analysis, linkage disequilibrium analysis, and univariate linear mixed models to identify significant single-nucleotide polymorphisms and candidate genes. (3) Results: Forty-five significantly related SNPs and 17 potential candidate genes associated with litter traits were identified. Individuals with the TT genotype at SNP rs341909772 showed an increase of 1.24 in the number of piglets born alive (NBA) and 1.25 in the number of healthy births (NHBs) compared with those with the CC genotype. (4) Conclusions: The SNPs and genes identified in this study offer insights into the genetics of reproductive traits in the Large White pig, potentially guiding the development of breeding strategies to improve litter size.

Comprehensive genome-wide analysis of genetic loci and candidate genes associated with litter traits in purebred Berkshire pigs of Korea.

The objective of this study was to identify genomic regions and candidate genes associated with the total number of piglets born (TNB), number of piglets born alive (NBA), and total number of stillbirths (TNS) in Berkshire pigs. This study used a total of 11,228 records and 2,843 single-nucleotide polymorphism (SNP) data obtained from Illumina porcine 60 K and 80 K chips. The estimated genomic breeding values (GEBVs) and SNP effects were estimated using weighted single-step genomic BLUP (WssGBLUP). The heritabilities of the TNB, NBA, and TNS were determined using single-step genomic best linear unbiased prediction (ssGBLUP). The heritability estimates were 0.13, 0.12, and 0.015 for TNB, NBA, and TNS, respectively. When comparing the accuracy of breeding value estimates, the results using pedigree-based BLUP (PBLUP) were 0.58, 0.60, and 0.31 for TNB, NBA, and TNS, respectively. In contrast, the accuracy increased to 0.67, 0.66, and 0.42 for TNB, NBA, and TNS, respectively, when using WssGBLUP, specifically in the last three iterations. The results of weighted single-step genome-wide association studies (WssGWAS) showed that the highest variance explained for each trait was predominantly located in the Sus scrofa chromosome 5 (SSC5) region. Specifically, the variance exceeded 4% for TNB, 3% for NBA, and 6% for TNS. Within the SSC5 region (12.26 to 12.76 Mb), which exhibited the highest variance for TNB, 20 SNPs were identified, and five candidate genes were identified: TIMP3, SYN3, FBXO7, BPIFC, and RTCB. The identified SNP markers for TNB, NBA, and TNS were expected to provide valuable information for genetic improvement as an understanding of their expression and genetic architecture in Berkshire pigs. With the accumulation of more phenotype and SNP data in the future, it is anticipated that more effective SNP markers will be identified.

Resolving the Intricate Effects of Multiple Global Change Drivers on Root Litter Decomposition.

Plant roots represent about a quarter of global plant biomass and constitute a primary source of soil organic carbon (C). Yet, considerable uncertainty persists regarding root litter decomposition and their responses to global change factors (GCFs). Much of this uncertainty stems from a limited understanding of the multifactorial effects of GCFs and it remains unclear how these effects are mediated by litter quality, soil conditions and microbial functionality. Using complementary field decomposition and laboratory incubation approaches, we assessed the relative controls of GCF-mediated changes in root litter traits and soil and microbial properties on fine-root decomposition under warming, nitrogen (N) enrichment, and precipitation alteration. We found that warming and N enrichment accelerated fine-root decomposition by over 10%, and their combination showed an additive effect, while precipitation reduction suppressed decomposition overall by 12%, with the suppressive effect being most significant under warming-alone and N enrichment-alone conditions. Significantly, changes in litter quality played a dominant role and accelerated fine-root decomposition by 15% ~ 18% under warming and N enrichment, while changes in soil and microbial properties were predominant and reduced decomposition by 7% ~ 10% under precipitation reduction and the combined warming and N enrichment. Examining only the decomposition environment or litter properties in isolation can distort global change effects on root decomposition, underestimating precipitation reduction impacts by 38% and overstating warming and N effects by up to 73%. These findings highlight that the net impact of GCFs on root litter decomposition hinges on the interplay between GCF-modulated root decomposability and decomposition environment, as well as on the synergistic or antagonistic relationships among GCFs themselves. Our study emphasizes that integrating the legacy effects of multiple GCFs on root traits, soil conditions and microbial functionality would improve our prediction of C and nutrient cycling under interactive global change scenarios.

Litter mixture effects on nitrogen dynamics during decomposition predominantly vary among biomes but little with litter identity, diversity and soil fauna

Nitrogen (N) is essential for net primary production, with much of the required N in terrestrial ecosystems derived from recycling via litter decomposition. The diversity and identity of plant species and decomposer organisms affect N cycling during litter decomposition, yet the generality and magnitude of these effects remain uncertain. To fill this gap, a decomposition experiment with four leaf litter species that differed widely in initial litter quality was conducted including single species and all possible multispecies mixtures, with and without microarthropods access across a broad latitudinal gradient covering four major forest biomes of the Northern Hemisphere. The results showed that leaf litter N dynamics (both N loss and N immobilization) in single species treatments depended primarily on litter species identity and the local environmental context. We found strong mixture effects, that overall tended to increase N loss and to reduce 15N transfer. The relative mixture effects on N dynamics differed among forest biomes, but were little affected by the other factors we manipulated. The N loss of individual litter species in mixtures not only depended on litter identity and soil microarthropod access, but also on forest biomes; while 15N transfer depended strongly on litter mixing, independently of litter species richness or composition of the mixtures. Litter N dynamics were mainly driven by a small subset of litter traits, regardless of species richness and microarthropod access. Overall, our results highlight that litter mixture strongly affects N dynamics during decomposition, with the mixture effects predominantly varying among forest biomes but little with litter identity, diversity and microarthropod access. To improve predictions on how changes in tree species composition and diversity may impact nutrient dynamics in forest ecosystems in face of increasing N deposition, interactions between litter and soil but also within litter mixtures need closer attention.

Research advance in effects of solar radiation on litter decomposition in terrestrial ecosystems.

Litter decomposition significantly influences the carbon (C) dynamics of terrestrial ecosystems. Solar radiation is not only essential for photosynthetic C fixation and primary productivity, but also can directly or indirectly promote litter decomposition through photodegradation. Recently, photodegradation has been identified as a key factor driving litter decomposition and potentially impacts terrestrial C cycle. To enrich and develop the theory of litter decomposition, we summarized the mechanisms and main driving factors of photodegradation, and compared the responses of photodegradation to environment and climate changes at different scales. Photodegradation primarily includes photomineralization, photoinhibition, and photofaciliation, each affecting litter decomposition differently under various environmental conditions. Photodegradation is closely related to factors such as solar radiation, litter traits, temperature, moisture, microorganisms, and vegetation cover. The interactions among these factors complicate the patterns of photodegradation. Finally, we identified the main issues in litter photodegradation research and prospected future research directions. We emphasized the needs for in-depth exploration of photodegradation pathways and intrinsic mechanisms, quantification of its interactive effects with environmental factors, and optimization of traditional carbon turnover models.

Enhancing paternal rabbit line’s litter size through backcrossing strategy

After 39 generations of selection, a commercial paternal rabbit line, utilised by farmers through artificial inseminations with sperm from males in a three-way crossbreeding scheme based on average daily weight gain merit (ADG), present a deleterious effect on the reproductive performance. This poses a challenge for the continuation of the breeding program. To address this, our study employed repeated backcrossing, a strategy widely used in the recovery of endangered breeds, to improve the litter size traits of this paternal line. For this purpose, we used a maternal line characterised by its reproductive robustness merit (LP line). The study was conducted in two phases: initially, elite males from the R line were crossed with females from the LP line, and female offspring (BC1) were backcrossed twice with elite males from the R line to create the RLP population (BC3). The best sires and dams from the BC3 population were selected for breeding based on two phenotypically criteria: more than 50 g/day in ADG and being part of a litter with at least 7 live kits at weaning, over three generations. With this experimental design, the ADG merit of sires and dams in the G3 was more than 51 g/day. Regarding litter traits, significant improvements were observed due to heterosis, which diminished as the frequency of R line genes increased. Comparisons between BC1 and BC3 backcrosses showed 9.94 vs. 7.80 for litter size at birth (NB), 9.13 vs. 6.53 for number born alive (NBA), 7.19 vs. 4.99 for litter size at weaning (NW), and 5.65 vs. 4.54 for litter size at marketing (NM), respectively. Nevertheless, after three generations of selection (G3), the litter trait merit showed values of 7.46 for NB and 6.15 for NBA, with heritability of 0.12 and 0.11, respectively, resulting in an improvement of nearly 1 kit per parity (a 25% increase) compared to the R line. Our study illustrated the possibility of improving a rabbit paternal line in terms of litter size merit by integrating genes from a maternal line through three backcrosses, without compromising the ADG merit. This is crucial for extending our breeding program beyond the current 39 generations. HIGHLIGHTS Three backcrossing resulting in an improvement of nearly 1 kit per parity Backcrossing can enhance litter size merit without affecting growth rates. Progeny average daily gain merit remains stable across backcrossing efforts.

270 Prenatal stress programming: Impact on dam and offspring immune phenotype and performance

Abstract Maternal stress during critical periods of fetal development is linked to the modified expression of several physiological processes. Despite attempts to minimize chronic stress and enhance sow well-being, some animals still experience stress, which can have short and long-term effects on future progeny. Therefore, we evaluated the impact of maternal stress on the immune phenotype and performance of pregnant gilts who had experienced pre- and post-natal stress and whether their offspring were affected. A total of 11 primiparous females (201.32 ± 17.18 kg at farrowing) clustered into treatment groups based on the treatment of their dams were used in this study. Their dams had been randomly allotted to receive either a placebo (CON) or Hydrocortisone Acetate capsules twice per day for 21 d during either mid (MID; d 51 to 72) or late (LATE; d 81 to 102) gestation. Prenatally stressed dams were sampled on gestational d 45, 60, 75, and 105 to determine descriptive and functional immune analysis. Productivity measures were assessed, including farrowing duration and the interval between piglets. Blood samples were taken from a subset of piglets born to these dams on d 7, 14, and 21 of lactation and then 24 h, 7, and 14 d post-wean. Data were analyzed using the Mixed procedure of SAS with repeated measures. Numbers of lymphocytes were elevated in gilts from LATE-treated dams compared with those from MID or CON dams for the entire study period (P < 0.05). All other descriptive immune measures, including neutrophil-to-lymphocyte ratio, were not different between groups during the gestational period. Mitogen-induced lymphocyte proliferation did not differ across treatments for prenatally stressed dams. No maternal treatment effects for any litter traits, farrowing duration, or interval between each piglet, but there was a tendency (P < 0.10) for piglets born to MID-stressed dams to be heavier than those born to CON dams. Total lymphocyte numbers were least in the progeny of MID-treated dams compared with piglets from LATE and CON dams for the entire lactation period. Over time, progeny from LATE-treated gilts had a more stimulated B-cell proliferation index during lactation (P < 0.05). Conversely, Concanavalin-A-induced lymphocyte proliferation tended to be least in offspring from MID-treated dams compared with CON. They also tended to have less percentage and numbers of lymphocytes than offspring from LATE and CON dams for the entire post-wean period. The offspring from MID-treated dams also had the greatest (P < 0.05) neutrophil-to-lymphocyte ratio for the entire period. While prenatal stress had minimal impact on the immune expression of the dam, its influence was evident in their progeny, particularly with MID. Results indicate that the programming effects may only be apparent in later generations. The study also suggests that mid-gestation is a more sensitive period for maternal stress in fetal development.

Feeding levels during early gestation in a group-housing system for primiparous sows: Impact on piglet birthweight and litter uniformity.

The current study investigated the impacts of different feeding regimes during early gestation on conception rate, litter traits, piglet birthweight, and litter uniformity in primiparous sows. In total, 108 primiparous sows were inseminated and assigned to either a standard (1.9±0.5 kg/day, S) or high (2.9±0.8 kg/day, H) feeding levels during the first 35 days of gestation. The feeding regimes were categorized based on periods of gestation: 1 to 3, 4 to 15, and 16 to 35 days, resulting in four groups: SSS (n=26), SSH (n=28), SHH (n=28), and HHH (n=26). Afterwards, sows were placed into a group-housed system equipped with electronic sow feeders. The sows were weighed and assessed for backfat thickness and loin muscle depth at 0 and 35 days of gestation. At farrowing, data were collected on the total number of piglets born per litter (TB), piglet birthweights, and the coefficient of variation of piglet birthweights. On average, sows gained 22.5±21.6 kg during the first 35 days of gestation, showing a positive correlation with backfat gain (r=0.954, p=0.006). The backfat gain in the HHH group was higher than in the SSS (p=0.016) and the SSH groups (p=0.023), but did not differ from the SHH group (p=0.684). Conception rates did not show differences among the feeding regimes (p>0.05). Individual piglet birthweights in the HHH group were higher than those in the SSH group (p<0.001). Likewise, the percentage of piglets with birthweights <1000 g in the HHH group was lower than that in the SSH group (p<0.001). However, the variation of piglet birthweight did not differ among the groups (p>0.05). Increasing feeding levels in primiparous sows in a group-housed system during early pregnancy can effectively restore their body condition without any detrimental effects on subsequent litters.

Secondary compounds increase litter removal by termites across 23 savanna grass species

Abstract Termites—one of the most abundant animal groups in tropical ecosystems—are vital in nutrient recycling, contributing significantly to maintaining ecosystem functioning. However, how selective they are in their litter food choice, and whether they prefer nutritious or less nutritious litter substrates, are still important unresolved questions. Here, we test the effect of litter traits on the removal of litter by fungus‐growing termites, a dominant group of macrodetritivores in the Serengeti‐Mara ecosystem. We used metal‐mesh litterbags to measure the mass loss of stem and leaf litter from 23 grass species after an incubation period of 61 days. Sheeting—soil deposits indicating termite presence—strongly increased with tannin and phenolic compounds, especially in leaf litter (R2 = 0.54), where highly aromatic species like Cymbopogon caesius and Bothriochloa insculpta exhibited the highest sheeting rates. Litterbags with sheeting displayed 66% higher mass loss on average compared to those without. Once termites had selected the substrate, mass loss increased consistently irrespective of litter traits. Quantifying the combined effects of sheeting frequency and differential mass loss, we found that fungus‐growing termites predominantly increased the mass loss of high‐nutrient litter. This was mainly due to additional mass loss in leaf litter, not stem litter, with tannin concentration being the primary predictor of enhanced overall decomposition by termites. This suggests termites ameliorate the otherwise adverse influence of plant secondary compounds on litter decomposition. Synthesis: Our results support the idea that fungus‐growing termites are generalists, as termites collected organic substrates with varying quality. The strong effect of phenolic compounds on sheeting rate implies that secondary compounds play an important role in termite substrate selection. The selective removal of substrates high in secondary compounds suggests fungus‐growing termites lift important constraints to microbial breakdown, potentially enhancing ecosystem‐level carbon and nutrient recycling rates. Termites play crucial roles in recycling organic matter across tropical biomes and our study highlights that the role of secondary compounds in their selection and detection in decomposition studies needs more attention

What makes decomposition faster under conspecific trees? The factors controlling the magnitude of home‐field advantage

The ‘home‐field advantage (HFA)' for decomposition means that leaf litter decomposes faster on soils under the conspecific species (i.e. the home field) than on soils under different species (i.e. ‘away'). Many previous studies have demonstrated the HFA, but the underlying mechanisms remain unclear. We conducted a reciprocal litter‐decomposition experiment using two species with different leaf traits: Abies mariesii, an evergreen conifer, and Fagus crenata, a deciduous broad‐leaved tree. Dominance of these species shifts along an elevation gradient with a transition zone where both species coexist. In mixed forests of the transition zone along the elevation gradient, we explored how the magnitude of HFA between these two species was influenced by temperature, soil properties, or leaf litter traits which could directly affect the decomposition rate. The magnitude of HFA observed between the two species varied widely from −3.89 to 28.3%. Our modeling showed that the magnitude of HFA increased with decreasing soil pH and leaf litter N, i.e. in more acidic soil and for less decomposable litter. Soil pH affected leaf litter decomposition in the home plots of each species, whereas leaf litter N did not. The magnitude of the HFA increased as the difference in soil pH between the F. crenata and A. mariesii plots at the same elevation became greater, but decreased as the difference in soil C became greater. Thus, the response of leaf litter decomposition to environmental changes might vary not only through direct effects of vegetation traits but also through indirect effects of the HFA. This highlights the importance of considering HFA for accurately predicting the response of local carbon and nutrient cycles to climate change, particularly in communities where a replacement of dominant species by others is expected due to climate change.

Sow reproductive performance following artificial insemination with semen doses processed using Single Layer Centrifugation without antibiotics in the tropics

Single Layer Centrifugation (SLC) through a low density colloid offers an alternative solution to antibiotic use in boar semen extenders, with lower costs compared to high density colloids. The aim of this study was to explore the reproductive performance of sows when using SLC-prepared semen doses without antibiotics, employing low density Porcicoll to prepare semen doses for artificial insemination in a commercial swine herd in Thailand. Ejaculates were divided into two equal parts to create insemination doses, with each dose containing 3000 × 106 sperm/80 ml for intra-uterine insemination in individual sows. The sows were inseminated twice, with the interval between the two inseminations ranging from 8 to 16 h. The CONTROL group consisted of 206 semen doses treated with antibiotics, prepared for insemination in 103 sows, while the SLC group comprised 194 SLC-prepared semen doses without antibiotics for inseminating 97 sows. Fertility and fecundity traits, including non-return rate, conception rate, farrowing rate, and litter traits (i.e., the total number of piglets born per litter, number of piglets born alive per litter, number of stillborn piglets, and number of mummified fetuses), were compared between groups. Furthermore, data on piglet characteristics, including live-born and stillborn piglets (i.e., the prevalence of stillbirth (yes, no), birth weight, crown-rump length, body mass index (BMI), and ponderal index (PI)), were determined. No significant differences in non-return rate (75.7 % vs. 77.3 %), conception rate (73.8 % vs. 73.2 %), and farrowing rate (71.8 % vs. 73.2 %) were observed between the CONTROL and SLC groups, respectively (P > 0.05). Nevertheless, the total number of piglets born per litter in the SLC group was higher than in the CONTROL group (14.6 ± 0.9 vs. 12.3 ± 0.6, respectively, P = 0.049). Interestingly, the prevalence of stillbirth in the SLC group was lower than in the CONTROL group (6.2 % vs. 11.6 %, respectively, P < 0.001). Moreover, the newborn piglets in the SLC group exhibited higher birth weight and BMI compared to those in the CONTROL group (1.36 ± 0.03 vs. 1.26 ± 0.02 kg, P = 0.005, and 18.3 ± 0.3 vs. 17.3 ± 0.2 kg/m2, P = 0.003). In conclusion, employing sperm doses after SLC through a low density colloid in artificial insemination within a commercial breeding operation did not have a detrimental impact on either fertility or fecundity traits but showed potential benefits in increasing the total number of piglets born per litter. Moreover, improvements were observed in the birth weight and body indexes of piglets, and the percentage of stillbirths was reduced. Our findings introduce new possibilities for antibiotic alternatives in semen extenders to reduce the risk of antimicrobial resistance in the swine industry. Additionally, they provide compelling reproductive outcomes supporting the integration of SLC-prepared semen doses into artificial insemination practices.

Cone and fruit impacts on understory flammability depend on traits and forest floor coverage

BackgroundUnderstory flammability is affected by abscised plant tissue. Extensive research has shown how interspecific differences in leaf litter traits affect flammability; however, leaves represent only one component of the litter layer. Cones and fruit are also common constituents of the forest floor, yet surprisingly little is known about how flammability is affected by their presence. In this study, we ask how flammability is affected by cones and fruit trait differences, coverage differences, and varying species and coverage combinations. To address these questions, we compared cone and fruit morphological and chemical traits among longleaf pine, loblolly pine, shortleaf pine, sweetgum, post oak, and water oak. We also used burn trials to compare fire behavior of single and mixed-species treatments at three coverage levels (10% of plot area (low), 30% (medium), and 50% (high)) integrated within a common mixed-litter layer under field conditions in central Alabama, USA.ResultsLike other plant tissues, cone/fruit dry matter, carbon, and lignin content promote fuel consumption and flame height, while nitrogen suppresses flammability. Single-species treatments produced distinct patterns in fire behavior, with longleaf pine cones consistently showing higher percent fuel consumption, flame height, and maximum smoldering temperature than sweetgum capsular heads. Mixed-species treatment results were less consistent; however, at high coverage, a representative upland three-way mixture (longleaf pine + sweetgum + post oak) showed significantly greater fuel consumption and flame height relative to a bottomland three-way mixture (loblolly pine + sweetgum + water oak) at high coverage. Medium cone/fruit coverage maximized flammability in most single and multi-species treatments and produced non-additive fuel consumption in mixtures containing longleaf pine and sweetgum.ConclusionOur results confirm that individual species’ cone and fruit flammability often parallels that of litter. Fire behavior in mixture is generally driven by the most flammable constituent species, but this result changes with cone and fruit coverage. Collectively, these results indicate that cones/fruit identity and coverage play an important role in understory flammability and should be integrated into fire behavior modeling efforts in monocultures and mixtures.

Multifaceted leaf litter traits shape soil fauna communities: Evidence from subtropical monocultural plantations

The important role of litter traits in shaping soil fauna communities has been increasingly acknowledged. It remains uncertain how fauna community features are associated with multiple litter traits, especially over the long term. With equal-aged monocultural plantations of 20 species in a subtropical climate in Hunan, China, we tested whether fauna communities were different after 40 years due to the landuse and choice of tree species, and the extent to which such disparity can be explained by litter traits. For each plantation plus a natural forest plot, we inventoried fauna in three layers (fresh litter, fragmentation and humus), measured fresh litter traits (leaf economics, size and shape and defenses), litter quantity and soil characteristics (soil properties, root and microbial biomass). Compared with natural forests, most plantations had similar fauna diversity indexes, but markedly lower density (-53.84%). Both density and diversity indexes generally increased from litter layers to humus: 0.89–1.71 for density, 32.45–38.03 for richness, 2.46–3.01 for Shannon-Wiener index, 0.82–0.92 for Gini-Simpson index and 0.74–0.84 for Pielou's evenness, respectively. Significant correlations between soil fauna indicators and litter traits were almost absent for litter layers, but were frequently observed in the humus layer. In the humus layer, soil fauna density was associated with traits related to economics (e.g., specific leaf area and dry matter content), defenses (e.g., phenol concentration) and metal element concentrations, but not with any size and shape traits, whereas soil fauna diversity could be associated with all the above trait categories. Both the leaf economics spectrum and size and shape spectrum could be significantly associated with the fauna indicators of the humus layer. Soil fauna indicators were more closely associated with litter traits than litter quantity and soil characteristics. This study reveals a link between soil fauna communities and litter traits at both individual traits and overall spectrum levels. The results emphasize the significance of segregating litter and soil layers in soil fauna studies, and the essential role of natural forests in preserving soil biodiversity.

228 The effect of temperature-humidity index in different pregnancy stages on litter traits in Taiwan Landrace sows

Abstract Because of climate change, annual average temperatures are gradually rising. Hence, increasing heat stress can impair the litter traits of Taiwanese sows located in tropical and subtropical zones. However, some pregnancy stages may be impacted more by heat stress than other periods. Thus, the purpose of this study was to demonstrate the effect of temperature-humidity index (THI) in different pregnancy stages on total number born (TNB), number born alive (NBA), and stillborn rate (STB). Data were collected in two Taiwanese farms from 2008 to 2021 for TNB, NBA, and STB, while weather data were collected from the closest respective weather station. There were 4,247 and 6,812 pure line Landrace record from farm 1 and farm 2, respectively. Pregnancy stages included 28 d before mating (BEFORE), mating to 30 d of pregnancy (EARLY), 31 to 70 d of pregnancy (MIDDLE), and 71 d of pregnancy to farrowing (LATE). Average THI was calculated in each pregnancy stage and regression coefficients were estimated by linear mixed models within ASReml. A two-trait analysis was used to estimate regression coefficients and genetic correlations among TNB, NBA, and STB. Results showed THI impacted (P &amp;lt; 0.05) TNB and NBA BEFORE and EARLY, while THI influenced (P &amp;lt; 0.05) STB EARLY and MIDDLE. Regression coefficients for TNB were -0.0069 and -0.0228 for BEFORE and EARLY, respectively. For NBA, regression coefficients were 0.0106 and -0.0391 for BEFORE and EARLY, respectively. Regression coefficients for STB were -0.0651 and 0.1332 for EARLY and MIDDLE, respectively. Heritability estimates for TNB, NBA, and STB were 0.168, 0.113, and 0.069, respectively. Genetic correlations between TNB with NBA and STB were 0.913 and 0.539, respectively. While the genetic correlation between NBA and STB was 0.158. In conclusion, THI impacted BEFORE and EARLY stages for TNB and NBA, while the stages of EARLY and MIDDLE were impacted by THI for STB. Hence, control of the environments in these specific stages for sows could improve the performance of litter traits.

The Influence of Forest Litter Characteristics on Bacterial and Fungal Community Diversity in the Picea crassifolia Ecosystem on the Qinghai–Tibet Plateau

The biodiversity and activity of microorganisms are crucial for litter decomposition, but how litter traits at different stages of decomposition drive changes in microbial communities has yet to be thoroughly explored. In the typical alpine hilly area of the Qinghai–Tibet Plateau, three types of litter at different decomposition stages were selected under a natural Picea crassifolia (Picea crassifolia Kom.) forest: undecomposed (A-1), partially decomposed (A-2), and fully decomposed (A-3). By measuring physicochemical indicators, microbial diversity, and the composition of the litter at different decomposition stages, this study investigates the community changes and responses of bacteria to litter characteristic changes at different decomposition levels. The results show that with the increase in decomposition level, bacterial diversity increases, community structure changes, and network complexity gradually increases, while the changes in fungal communities are insignificant. Structural equation modeling indicates that the first principal component (PC1) of litter properties is significantly negatively correlated with bacterial diversity and positively correlated with bacterial community composition. There is no significant correlation between fungal diversity and community composition, indicating a closer relationship between bacteria and litter characteristics than fungi. In summary, with an increase in litter decomposition level, the diversity and network complexity of bacterial and fungal communities will significantly increase, which is related to the changes in various litter characteristics. This study provides a scientific basis for the regulatory mechanism of litter decomposition and turnover in the alpine hilly area of the Qinghai–Tibet Plateau, specifically in Picea crassifolia forests.

Rapid estimates of leaf litter chemistry using reflectance spectroscopy

Measuring the chemical traits of leaf litter is important for understanding plants’ influence on nutrient cycles, including through nutrient resorption and litter decomposition, but conventional leaf trait measurements are often destructive and labor-intensive. Here, we develop and evaluate the performance of partial least-squares regression models that use reflectance spectra of intact or ground leaves to estimate leaf litter traits, including carbon and nitrogen concentration, carbon fractions, and leaf mass per area (LMA). Our analyses included more than 300 samples of senesced foliage from 11 species of temperate trees, including both needleleaf and broadleaf species. Across all samples, we could predict each trait with moderate-to-high accuracy from both intact-leaf litter spectra (validation R2 = 0.543–0.941; %root mean squared error (RMSE) = 7.49–18.5) and ground-leaf litter spectra (validation R2 = 0.491–0.946; %RMSE = 7.00–19.5). Notably, intact-leaf spectra yielded better predictions of LMA. Our results support the feasibility of building models to estimate multiple chemical traits from leaf litter of a range of species. In particular, intact-leaf spectral models allow non-destructive trait estimation in a matter of seconds, which could enable researchers to measure the same leaves over time in studies of nutrient resorption.

Litter Decomposition of a Deciduous Tectona philippinensis and an Evergreen Parashorea malaanonan Across Contrasting Sites

Litter traits and site conditions alter nutrient inputs from deciduous and evergreen forests by influencing litter decomposition processes. Here, we investigated the leaf and stem mass loss rate (MLR) of a deciduous (Tectona philippinensis) and an evergreen (Parashorea malaanonan) tree species and the factors influencing it through an intersite experiment and litterbag method in secondary forests in Lobo, Batangas and Mount Makiling Forest Reserve (MMFR). Variations in initial litter quality (leaf area, specific leaf area (SLA), leaf thickness, vein density), and site factors (light intensity and temperature) were assessed. P. malaanonan has a lower SLA and vein density than T. philippinensis. The leaf and stem MLR were significantly higher in the mixed litter (44.09–57.83%) than that of a single-species litter of either T. philippinensis (28.16–41.83%) or P. malaanonan (33.60–47.66%). The leaf MLR of T. philippinensis was greater when placed in Lobo (where the litter originated) than at a different site (i.e., MMFR). Moreover, leaf litter decomposition was faster in T. philippinensis than in P. malaanonan, particularly during the rainy season. Overall, the study showed that litter decomposition in deciduous and evergreen differed across sites due to variations in litter quality and environmental variables. Keywords: decomposability traits, home-field advantage (HFA), intersite experiment, litter quality, mass loss rate

Effect of Body Weight and Age at Puberty and Mating on Subsequent Gilt Development Weights, Litter Traits, and Colostral Immunoglobulin G of the F1 Large White X Landrace Gilts

Effect of Body Weight and Age at Puberty and Mating on Subsequent Gilt Development Weights, Litter Traits, and Colostral Immunoglobulin G of the F1 Large White X Landrace Gilts

The effect of litter decomposition mostly depends on seasonal variation of ultraviolet radiation rather than species in a hyper-arid desert

Introduction: Ultraviolet (UV) radiation is believed to play a significant role in accelerating litter decomposition in water-limited ecosystems. Litter traits also influence the decomposition. However, the dominance of litter traits and ultraviolet radiation on litter decomposition in hyper-arid deserts (annual precipitation: potential evaporation &amp;lt; 0.05) with diverse species and seasonal variations remain unclear.Methods: To address this knowledge gap, we examined the decomposition of three dominant litter species (Karelinia caspia, Alhagi sparsifolia, and Populus euphratica) in the southern edge of the Taklimakan Desert, Northwest China.Results: Our results revealed that under UV radiation conditions, K. caspia, A. sparsifolia, and P. euphratica experienced mass losses of 45.4%, 39.8%, and 34.9%, respectively, and 20%, 22.2% and 17.4%, respectively under UV filtering treatment. Specifically, the loss rate of carbon and lignin under UV radiation, was 2.5 and 2.2 times higher than under UV filtering treatment, respectively.Conclusion: UV radiation did not dominate decomposition throughout the year in our study area, and the loss rate of litter traits was significantly higher in summer than in winter under UV radiation. Moreover, this photodegradation is related to the intensity of UV exposure, but not to precipitation or temperature. Surprisingly, species type had no significant effect on litter decomposition. However, when we applied a UV filtering treatment, we observed higher loss rates of nitrogen compared with the ambient treatment, suggesting the involvement of other spectra in the litter decomposition process. Overall, our findings elucidate that UV radiation is a crucial factor that affects litter mass loss. The magnitude of this effect mostly varies with the season rather than the species of litter.