Scientific Journals of INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria)
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A model for longitudinal data sets relating wind-damage probability to biotic and abiotic factors: a Bayesian approach
Get PDFAim of study: To develop a statistical model framework to analyze longitudinal wind-damage records while accounting for autocorrelation, and to demonstrate the usefulness of the model in understanding the regeneration process of a natural forest.Area of study: University of Tokyo Chiba Forest (UTCBF), southern Boso peninsula, Japan.Material and methods: We used the proposed model framework with wind-damage records from UTCBF and wind metrics (speed, direction, season, and mean stand volume) from 1905–1985 to develop a model predicting wind-damage probability for the study area. Using the resultant model, we calculated past wind-damage probabilities for UTCBF. We then compared these past probabilities with the regeneration history of major species, estimated from ring records, in an old-growth fir–hemlock forest at UTCBF.Main results: Wind-damage probability was influenced by wind speed, direction, and mean stand volume. The temporal pattern in the expected number of wind-damage events was similar to that of evergreen broad-leaf regeneration in the old-growth fir–hemlock forest, indicating that these species regenerated after major wind disturbances.Research highlights: The model framework presented in this study can accommodate data with temporal interdependencies, and the resultant model can predict past and future patterns in wind disturbances. Thus, we have provided a basic model framework that allows for better understanding of past forest dynamics and appropriate future management planning.Keywords: dendrochronology; tree regeneration; wind-damage probability model; wind disturbance.Abbreviations used: intrinsic CAR model (intrinsic conditional autoregressive model); MCMC (Markov chain Monte Carlo); 16 compass points = N, NNE, NE, ENE, E, ESE, SE, SSE, S, SSW, SW, WSW, W, WNW, NW, NNW (north, north-northeast, northeast, east-northeast, east, east-southeast, southeast, south-southeast, south, south-southwest, southwest, west-southwest, west, west-northwest, northwest, north-northwest, respectively); UTCBF (the University of Tokyo Chiba Forest)
New set of microsatellite markers for the walnut hybrid progeny Mj209xRa and assessment of its transferability into Juglans genus
Get PDFAim of the study: The research was aimed to design microsatellite markers for genotyping and differentiation of trees from the walnut hybrid progeny Mj209×Ra. As a secondary objective, the transferability and classificatory capacity of some of these loci were assessed for Juglans genus.Area of study: The most widely spread walnut hybrid progeny used in Europe for wood production was used. Pure species from Juglans genus as Arizona black walnut (J. major (Torrey) Heller) and European or common walnut (J. regia L.), as well as a different hybrid Mj209xRa lots, were also included.Materials and methods: Genomic DNA from a hybrid tree was used for the construction of libraries enriched with dinucleotides repeats (CA/GA). From approximately 700 fragments containing SSR regions, 18 loci were finally selected for the genetic characterization. Eight of these genomic microsatellite markers were used to assess their transferability into Juglans genus. Main results: Despite the high degree of kinship of the hybrid progeny, it was possible to differentiate random trees with a low probability of error. Markers also allowed to differentiate unambiguously between Arizona black walnut and European walnut. They were even able to discriminate two hybrid Mj209×Ra lots with a high degree of certainty.Research highlights: This new set of microsatellites might be considered a complement for the markers published up to date to perform studies into Juglandaceae family.Keywords: Juglandaceae; wood production; genotyping; genotype identification; simple sequence repeats; SSR.
Seasonal dynamics of soil microbial biomass in fragmented patches of subtropical humid forest of Jaintia hills in Meghalaya, Northeast India
Get PDFAim of the study: The aim of the study was to assess the seasonal dynamics of microbial biomass and its contribution to soil system along a fragment size gradient in subtropical humid forest of Meghalaya. Area of study: The study was conducted in forest fragments located at Jarain and adjoining areas in Jaintia Hills of Meghalaya, northeast India.Material and Methods: Forest fragments of sizes ranging from 3.8 to 105 ha were selected for the study and grouped into Small (< 5 ha), Medium (> 5 and < 15 ha), Large (>15 and < 50 ha) and Very Large (105 ha) classes. Three experimental plots each of 20 x 20 m were established at the forest edge and at 50 m distance assigned as ‘interior’ microsite in each of the fragments for sampling of soil. Soil samples (0-10 cm depth) from each of the experimental plots were collected in replicates on seasonal interval and microbial biomass was estimated by the fumigation extraction method.Important findings: Microbial biomass- C, -N and -P varied significantly (p< 0.05) between the fragment sizes, microsites and seasons. The microbial biomass was higher in the interior as compared to the edge. It was also high during the winter season. Overall, soil microbial biomass -C, -N and -P ranged from 260 to 969; 25 to 95 and 8 to 67 µg g-1 respectively. The contribution of microbial biomass -C, -N and -P to soil organic carbon, total Kjeldahl nitrogen and phosphorus ranged from 1.48 to 1.81 %, 2.54 to 4.54 % and 3.41 to 5.22 % respectively. Fragmentation alters the microenvironmental conditions and soil properties that in turn affect the microbial biomass. Highlights: This interaction of plant, soil and microbial community would gradually degrade in the fragments due to change in vegetation composition and structure, microclimatic conditions and soil physical and chemical properties. Our results suggests that microbial mediated ecosystem processes such as nutrient cycling are more susceptible to variation at the edge which may become unstable and unpredictable in forest fragments exposed to various human disturbances.Keywords: fragment size, microbial biomass, microenvironment, subtropical forest
Modelling approaches for mixed forests dynamics prognosis. Research gaps and opportunities
Get PDFAim of study: Modelling of forest growth and dynamics has focused mainly on pure stands. Mixed-forest management lacks systematic procedures to forecast the impact of silvicultural actions. The main objective of the present work is to review current knowledge and forest model developments that can be applied to mixed forests.Material and methods: Primary research literature was reviewed to determine the state of the art for modelling tree species mixtures, focusing mainly on temperate forests.Main results: The essential principles for predicting stand growth in mixed forests were identified. Forest model applicability in mixtures was analysed. Input data, main model components, output and viewers were presented. Finally, model evaluation procedures and some of the main model platforms were described.Research highlights: Responses to environmental changes and management activities in mixed forests can differ from pure stands. For greater insight into mixed-forest dynamics and ecology, forest scientists and practitioners need new theoretical frameworks, different approaches and innovative solutions for sustainable forest management in the context of environmental and social changes.Keywords: dynamics, ecology, growth, yield, empirical, classification
Species composition and structure of an exotic Quercus suber stand on the island of Gran Canaria (Canary Islands)
Get PDFAim of the study: Although introduced tree species have been recognized as adversely affecting native ecosystems, conversely, some studies suggest they can facilitate recovery and promote the establishment of native plant communities. This study tests whether a native plant community is established under the closed canopies of an exotic species by analyzing regeneration and plant species composition.Area of study: Finca de Osorio, a public property of the Cabildo de Gran Canaria included in the Doramas Rural Park (Canary Islands, Spain).Main results: The results reveal that sapling regeneration is dominated by the exotic species, though some native ones are also present. The sapling regeneration community did not differ from the tree canopy composition, so, a native plant community recovery cannot be expected to occur. In addition, other introduced species were also present in the sapling composition community.Research highlights: The laurel forest of the Canary Islands is the most emblematic plant community of the Canary Island archipelago. The studied area dominated by Q. suber does not favor the regeneration of the native plant community. Thus, restoration programs will be required to enhance the native plant community and the area covered by this highly disturbed plant ecosystem on the island of Gran Canaria.Keywords: catalytic effect; invasion; laurel forest; plant community
Effect of tillage system on the structure of weed infestation of winter wheat
Get PDFThe study aimed to evaluate the structure of weed infestation of winter wheat grown in different weeding systems: conventional tillage (CT), reduced tillage (RT), and herbicide treatment (HT). In CT system, shallow ploughing and pre-sow ploughing were conducted after the harvest of the previous crop. In RT system, shallow ploughing was replaced by cultivator tillage, whereas pre-sow ploughing by a tillage set. In HT system, shallow ploughing was replaced by spraying with glyphosate and pre-sow ploughing by cultivator tillage. At the tillering stage (22-23 in BBCH scale), species composition and number of weeds/m2 were determined with the botanical-gravimetric method, whereas at the stage of waxy maturity of wheat (82-83 BBCH) analyses were conducted for species composition as well as density, air-dry weight, and weed distribution in crop levels. The Shannon-Wiener’s diversity index (H’) and degrees of phytosociological constancy (S) of weeds were determined as well. The study showed that more weeds occurred in RT and HT systems than in the CT system and they produced higher biomass in RT than in CT and HT systems. The tillage system affected weed distribution in crop levels. In CT system, the highest weed density was identified in the ground and lower levels, whereas in RT and HT systems in the ground and middle levels. Values of the species diversity index (H’) indicate a similar diversity of weed species composition between weeding systems and more diverse between study years
Short communication: Identification and relationship of the autochthonous ‘Romé’ and ‘Rome Tinto’ grapevine cultivars
Get PDFThe ‘Romé’ variety is considered an Andalusian (southern region in Spain) autochthonous black grape cultivar. However, several white and black grapevine accessions are known by this name, according to Vitis International Variety Catalogue. The aim of the present work was to clarify the identity of the ‘Romé’ and ‘Rome Tinto’ as black grapevine cultivar. Eight accessions known as ‘Romé’ and two as ‘Rome Tinto’ were analyzed using 30 OIV descriptors and 22 SSR loci. The morphologic and genetic analysis showed that all accessions studied presented the same genotype and phenotype and grouped with South Spanish cultivars. This study helps to clarify the confusion over the identity of ‘Romé’ grapevine cultivar, and provides a solid basis to develop a germplasm collection to protect grapevine diversity and to recover cultivars that may be in danger of extinction
Milk yield, periparturient diseases and body condition score as factors affecting the risk of fetal losses in high-yielding Holstein cows
Get PDFThe objective of this study was to assess various risk factors affecting fetal losses in high-yielding Holstein cows in a hot environment. In a retrospective observational study, 14,384 records from Holstein cows from a large highly technified dairy herd in northern Mexico were used. Logistic multivariate multiple-group response model indicated that fetal losses between 43 and 260 days of pregnancy were 23.8%. Dry periods >60 d were associated (p<0.05) with 0.8 (confidence interval CI=0.8–0.9) times lower incidence of fetal losses compared to cows with dry periods <60 d. Cows with body condition score (BCS) >3 at calving and 15 days postpartum had about half the risk of suffering fetal losses than cows with BCS <3.0. Cows with peak milk yield >38 kg were 5.5 times more likely to have a fetal loss than cows with peak milk yield <38 kg (36.9 vs. 9.6%; p<0.01). The risk of fetal loss increased with 305-d milk yield >9,000 kg (OR=2.1) compared with cows with milk yield <9,000 kg. Retained placenta was (p<0.05) associated with 1.2 (CI=1.1–1.4) times higher fetal losses than cows without this reproductive disorder. Cows suffering premature parturition had 1.2 (CI=1.0–1.4) greater (p<0.05) risk of suffering fetal losses than cows with normal parturition. Cows with twin pregnancies had significantly increased chances of losing their fetuses than cows with a single fetus (31.1 vs. 15.9 p<0.01). A bimodal distribution of fetal losses was observed with peaks around 50 and 220 days of pregnancy. It was concluded that in this particular hot environment fetal losses were associated with high milk yield, low body energy reserves at calving, reduced dry periods, occurrence of retained placenta, twin pregnancies and premature calving