Litterfall, litter decomposition and associated nutrient fluxes in Pinus halepensis: influence of tree removal intensity in a Mediterranean forest

The online version of this article (doi:10.1007/s10342-015-0893-z) contains supplementary material, which is available to authorized users[EN] Our knowledge about the influence of silvicultural treatments on nutrient cycling processes in Mediterranean forests is still limited. Four levels of tree removal were compared in an Aleppo pine forest in eastern Spain to determine the effects on litterfall, litter decomposition and the associated nutrient fluxes after 12 years. Removal treatments included clearfelling, two shelterwood intensities (60 and 75 % of basal area removed) and untreated controls. Twelve years later, the basal area removed still explained 60 % of litterfall mass variance and 60 % of C, 52 % of N, 45 % of P, 17 % of K, 47 % of Ca and 60 % of Mg return variances. Litter decomposed somewhat more slowly in clearfellings compared to controls (p = 0.049), accumulated more Ca and released less K compared to the other three treatments. This was explained by contamination with mineral particles due to the poorly developed O horizon in clearfellings. We conclude that the management practices reduced the nutrient return via litterfall, but the nutrient release through decomposition seems poorly sensitive to canopy disturbance. In order to accurately quantify the harvesting impacts on nutrient cycling in this Mediterranean forest system, it is necessary to measure the litterfall of the understory layer.This work has been supported by a fellowship from the Generalitat Valenciana, Conselleria de Educacion, Formacion y Empleo awarded to L. Lado-Monserrat (BFPI/2008/041). Silvicultural treatments were carried out by the Mediterranean Centre for Environmental Studies (CEAM) through programme "I + D en relacion con la restauracion de la cubierta vegetal y otros aspectos de investigacion forestal". Dataloggers and probes were provided by the Generalitat Valenciana through Project "Efecto de diferentes sistemas de aclareo de masa forestal sobre la disponibilidad de agua, nutrientes y la regeneracion de la masa arborea y arbustiva en parcelas de pinar" (GV06/126). We acknowledge Joana Oliver, Ruth M. Tavera and Daniel Fortanet for their help in the laboratory and in the field. The authors wish to thank Francisco Galiana for his assistance, including help in fieldwork and providing information about the experimental design of the silvicultural treatments. Thanks also go to Rafael Herrera from the Centro de Ecologia, Instituto Venezolano de Investigaciones Cientificas, Caracas, Venezuela and two anonymous reviewers for critically reviewing the manuscript.Lado Monserrat, L.; Lidón, A.; Bautista, I. (2015). Litterfall, litter decomposition and associated nutrient fluxes in Pinus halepensis: influence of tree removal intensity in a Mediterranean forest. European Journal of Forest Research. 134(5):833-844. https://doi.org/10.1007/s10342-015-0893-zS8338441345Almagro M, Martínez-Mena M (2012) Exploring short-term leaf-litter decomposition dynamics in a Mediterranean ecosystem: dependence on litter type and site conditions. Plant Soil 358:323–335Alvarez A, Gracia M, Vayreda J, Retana J (2012) Patterns of fuel types and crown fire potential in Pinus halepensis forests in the Western Mediterranean Basin. For Ecol Manage 270:282–290Austin AT, Vivanco L (2006) Plant litter decomposition in a semi-arid ecosystem controlled by photodegradation. Nature 442:555–558Bates JD, Svejcar TS, Miller RF (2007) Litter decomposition in cut and uncut western juniper woodlands. J Arid Environ 70:222–236Binkley D (2008) Three key points in the design of forest experiments. For Ecol Manage 255:2022–2023Blair JM, Crossley DA Jr (1988) Litter decomposition, nitrogen dynamics and litter microarthropods in a southern Appalachian hardwood forest 8 years following clearcutting. J Appl Ecol 25:683–698Blanco JA, Zavala MA, Imbert JB, Castillo FJ (2005) Sustainability of forest management practices: evaluation through a simulation model of nutrient cycling. For Ecol Manage 213:209–228Blanco JA, Imbert JB, Castillo FJ (2006) Influence of site characteristics and thinning intensity on litterfall production in two Pinus sylvestris L. forests in the western Pyrenees. For Ecol Manage 237:342–352Blanco JA, Imbert JB, Castillo FJ (2008) Nutrient return via litterfall in two contrasting Pinus sylvestris forests in the Pyrenees under different thinning intensities. For Ecol Manage 256:1840–1852Blanco JA, Imbert JB, Castillo FJ (2011) Thinning affects Pinus sylvestris needle decomposition rates and chemistry differently depending on site conditions. Biogeochemistry 106:397–414Caldentey J, Ibarra M, Hernández J (2001) Litter fluxes and decomposition in Nothofagus pumilio stands in the region of Magallanes, Chile. For Ecol Manage 148:145–157Christensen JH, Krishna Kumar K, et al. (2013) Climate phenomena and their relevance for future regional climate change. In: Stocker TF, Qin D, Plattner G-K et al (Eds.) Climate change 2013: the physical science basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USACortina J, Vallejo VR (1994) Effects of clearfelling on forest floor accumulation and litter decomposition in a radiata pine plantation. For Ecol Manage 70:299–310Entry JA, Rose CL, Cromack K Jr (1991) Litter decomposition and nutrient release in ectomycorrhizal mat soils of a Douglas fir ecosystem. Soil Biol Biochem 23:285–290Fabbio G, Merlo M, Tosi V (2003) Silvicultural management in maintaining biodiversity and resistance of forests in Europe—the Mediterranean region. J Environ Manage 67:67–76Galiana F, Pérez-Badía R, Camarero E, Estruch V, Currás R (2001) Estimación de la Radiación solar incidente en pinares de Pinus halepensis sometidos a tratamientos selvícolas de cortas finales. In: Junta de Andalucía. Consejería de Medio Ambiente (Ed.) Actas del III Congreso Forestal Español. Junta de Andalucía. Granada (Original in Spanish)García-Plé C, Vanrell P, Morey M (1995) Litter fall and decomposition in a Pinus halepensis forest on Mallorca. J Veg Sci 6:17–22González Utrillas N, González Pérez E, Galiana F (2005) Variación del crecimiento diametral de la masa de pinar de carrasco en cortas finales experimentales, en los montes de Tuejar y Chelva (Valencia). IV Congreso Forestal Español. Zaragoza. Soc. Esp. Cien. For. (Original in Spanish)Guo LB, Sims REH (1999) Litter decomposition and nutrient release via litter decomposition in New Zealand eucalypt short rotation forests. Agric Ecosyst Environ 75:133–140GVA (1995) Mapa de Suelos de la Comunidad Valenciana. Chelva (666). Proyecto LUCDEME (Icona), Centro de Investigaciones sobre Desertificación y Conselleria d’Agricultura i Mig Ambient. Generalitat Valenciana. Valencia, Spain. (Original in Spanish)Hennessey TC, Dougherty PM, Cregg BM, Wittwer RF (1992) Annual variation in needle fall of a loblolly pine stand in relation to climate and stand density. For Ecol Manage 51:329–338Inagaki Y, Kuramoto S, Torii A, Shinomiya Y, Fukata H (2008) Effects of thinning on leaf-fall and leaf-litter nitrogen concentration in hinoki cypress (Chamaecyparis obtusa Endlicher) plantation stands in Japan. For Ecol Manage 255:1859–1867Jonard M, Misson L, Ponette Q (2006) Long-term thinning effects on the forest floor and the foliar nutrient status of Norway spruce stands in the Belgian Ardennes. Can J For Res 36:2684–2695Kim C, Sharik TL, Jurgensen MF (1996a) Canopy cover effects on mass loss, and nitrogen and phosphorus dynamics from decomposing litter in oak and pine stands in northern Lower Michigan. For Ecol Manage 80:13–20Kim C, Sharik TL, Jurgensen MF (1996b) Litterfall, nitrogen and phosphorus inputs at various levels of canopy removal in oak and pine stands in northern lower Michigan. Am Midl Nat 135:195–204Kim C, Son Y, Lee WK, Jeong J, Noh NJ, Kim SR, Yang AR, Ju NG (2012) Influence of forest tending (Soopkakkugi) works on litterfall and nutrient inputs in a Pinus densiflora stand. For Sci Technol 8:83–88Kimmins JP (2004) Forest ecology, a foundation for sustainable management and environmental ethics in forestry. Prentice-Hall, New JerseyKimmins JP, Mailly D, Seely B (1999) Modelling forest ecosystem net primary production: the hybrid simulation approach used in FORECAST. Ecol Modell 122:195–224Klemmedson JO, Meier CE, Campbell RE (1990) Litter fall transfers of dry matter and nutrients in ponderosa pine stands. Can J For Res 20:1105–1115Kunhamu TK, Kumar BM, Viswanath S (2009) Does thinning affect litterfall, litter decomposition, and associated nutrient release in Acacia mangium stands of Kerala in peninsular India? Can J For Res 39:792–801Lytle DE, Cronan CS (1998) Comparative soil CO2 evolution, litter decay, and root dynamics in clearcut and uncut spruce–fir forest. For Ecol Manage 103:121–128Molina AJ, Del Campo AD (2012) The effects of experimental thinning on throughfall and stemflow: a contribution towards hydrology-oriented silviculture in Aleppo pine plantations. For Ecol Manage 269:206–213Navarro FB, Romero-Freire A, Del Castillo T, Foronda A, Jiménez MN, Ripoll MA, Sánchez-Miranda A, Hutsinger L, Fernández-Ondoño E (2013) Effects of thinning on litterfall were found after years in a Pinus halepensis afforestation area at tree and stand levels. For Ecol Manage 289:354–362Olson JS (1963) Energy storage and the balance of producers and decomposers in ecological systems. Ecology 44:322–331Pérez Cueva AJ (1994) Atlas Climático de la Comunidad Valenciana. Colección Territori nº 4. Generalitat Valenciana. Conselleria d’Obres Publiques, Urbanisme i Transport, ValenciaPetritsch R, Hasenauer H, Pietsch SA (2007) Incorporating forest growth response to thinning within biome-BGC. For Ecol Manage 242:324–336Prescott CE (1997) Effects of clearcutting and alternative silvicultural systems on rates of decomposition and nitrogen mineralization in a coastal montane coniferous forest. For Ecol Manage 95:253–260Prescott CE (2002) The influence of the forest canopy on nutrient cycling. Tree Physiol 22:1193–1200Prescott CE, Blevins LL, Staley CL (2000) Effects of clear-cutting on decomposition rates of litter and forest floor in forests of British Columbia. Can J For Res 30:1751–1757Roig S, Del Río M, Cañellas I, Montero G (2005) Litter fall in Mediterranean Pinus pinaster Ait. stands under different thinning regimes. For Ecol Manage 206:179–190Sardans J, Peñuelas J, Rodà F (2005) Changes in nutrient use efficiency, status and retranslocation in young post-fire regeneration Pinus halepensis in response to sudden N and P input, irrigation and removal of competing vegetation. Trees 19:233–250Scarascia-Mugnozza G, Oswald H, Piussi P, Radoglou K (2000) Forests of the Mediterranean region: gaps in knowledge and research needs. For Ecol Manage 132:97–109Slovik S (1997) Tree physiology. In: Hüttl RF, Schaaf W (eds) Magnesium deficiency in forest ecosystems. Kluwer Academic Publishers, London, pp 101–214Taylor BR, Parkinson D (1988) Does repeated freezing and thawing accelerate decay of leaf litter? Soil Biol Biochem 20:657–665Torras O, Saura S (2008) Effects of silvicultural treatments on forest biodiversity indicators in the Mediterranean. For Ecol Manage 255:3322–3330Trofymow JA, Barclay HJ, McCullough KM (1991) Annual rates and elemental concentrations of litter fall in thinned and fertilized Douglas-fir. Can J For Res 21:1601–1615Wallace ES, Freedman B (1986) Forest floor dynamics in a chronosequence of hardwood stands in central Nova Scotia. Can J For Res 16:293–302Whitford WG, Meentemeyer V, Seastedt TR, Cromack Jr K, Crossley Jr DA, Santos P, Todd RL, Waide JB (1981) Exceptions to the AET model: deserts and clear-cut forest. Ecology 62:275–277Yin X, Perry JA, Dixon RK (1989) Influence of canopy removal on oak forest floor decomposition. Can J For Res 19:204–21

Early-life exposure to environmental contaminants perturbs the sperm epigenome and induces negative pregnancy outcomes for three generations via the paternal lineage

Due to the grasshopper effect, the Arctic food chain in Canada is contaminated with persistent organic pollutants (POPs) of industrial origin, including polychlorinated biphenyls and organochlorine pesticides. Exposure to POPs may be a contributor to the greater incidence of poor fetal growth, placental abnormalities, stillbirths, congenital defects and shortened lifespan in the Inuit population compared to non-Aboriginal Canadians. Although maternal exposure to POPs is well established to harm pregnancy outcomes, paternal transmission of the effects of POPs is a possibility that has not been well investigated. We used a rat model to test the hypothesis that exposure to POPs during gestation and suckling leads to developmental defects that are transmitted to subsequent generations via the male lineage. Indeed, developmental exposure to an environmentally relevant Arctic POPs mixture impaired sperm quality and pregnancy outcomes across two subsequent, unexposed generations and altered sperm DNA methylation, some of which are also observed for two additional generations. Genes corresponding to the altered sperm methylome correspond to health problems encountered in the Inuit population. These findings demonstrate that the paternal methylome is sensitive to the environment and that some perturbations persist for at least two subsequent generations. In conclusion, although many factors influence health, paternal exposure to contaminants plays a heretofore-underappreciated role with sperm DNA methylation contributing to the molecular underpinnings involved

Functional outcome after perineal stapled prolapse resection for external rectal prolapse

<p>Abstract</p> <p>Background</p> <p>A new surgical technique, the Perineal Stapled Prolapse resection (PSP) for external rectal prolapse was introduced in a feasibility study in 2008. This study now presents the first results of a larger patient group with functional outcome in a mid-term follow-up.</p> <p>Methods</p> <p>From December 2007 to April 2009 PSP was performed by the same surgeon team on patients with external rectal prolapse. The prolapse was completely pulled out and then axially cut open with a linear stapler at three and nine o'clock in lithotomy position. Finally, the prolapse was resected stepwise with the curved Contour^®Transtar™ stapler at the prolapse's uptake. Perioperative morbidity and functional outcome were prospectively measured by appropriate scores.</p> <p>Results</p> <p>32 patients participated in the study; median age was 80 years (range 26-93). No intraoperative complications and 6.3% minor postoperative complications occurred. Median operation time was 30 minutes (15-65), hospital stay 5 days (2-19). Functional outcome data were available in 31 of the patients after a median follow-up of 6 months (4-22). Preoperative severe faecal incontinence disappeared postoperatively in 90% of patients with a reduction of the median Wexner score from 16 (4-20) to 1 (0-14) (<it>P </it>< 0.0001). No new incidence of constipation was reported.</p> <p>Conclusions</p> <p>The PSP is an elegant, fast and safe procedure, with good functional results.</p> <p>Trial registration</p> <p>ISRCTN68491191</p

From the Shell-shocked Soldier to the Nervous Child: Psychoanalysis in the Aftermath of the First World War

This article investigates the development of child analysis in Britain between the wars, as the anxious child succeeded the shell-shocked soldier as a focus of psychoanalytic enquiry. Historians of psychoanalysis tend to regard the Second World War as a key moment in the discovery of the ‘war within’ the child, but it was in the aftermath of the First War that the warring psyche of the child was observed and elaborated. The personal experience of war and its aftermath, and the attention given to regression in the treatment of war neuroses, encouraged Melanie Klein, Anna Freud and others to turn their attention to children. At the same time, however, the impact of the First World War as a traumatic event, with inter-generational consequences, remained largely unaccounted for within psychoanalysis as Klein and others focused on the child's riven internal world

Polypeptide-grafted macroporous polyHIPE by surface-initiated N-Carboxyanhydride (NCA) polymerization as a platform for bioconjugation

A new class of functional macroporous monoliths from polymerized high internal phase emulsion (polyHIPE) with tunable surface functional groups was developed by direct polypeptide surface grafting. In the first step, amino-functional polyHIPEs were obtained by the addition of 4-vinylbenzyl or 4-vinylbenzylphthalimide to the styrenic emulsion and thermal radical polymerization. The obtained monoliths present the expected open-cell morphology and a high surface area. The incorporated amino group was successfully utilized to initiate the ring-opening polymer- ization of benzyl-L-glutamate N-carboxyanhydride (BLG NCA) and benzyloxycarbonyl-L-lysine (Lys(Z)) NCA, which resulted in a dense homogeneous coating of polypeptides throughout the internal polyHIPE surfaces as confirmed by SEM and FTIR analysis. The amount of polypeptide grafted to the polyHIPE surfaces could be modulated by varying the initial ratio of amino acid NCA to amino-functional polyHIPE. Subsequent removal of the polypeptide protecting groups yielded highly functional polyHIPE-g-poly(glutamic acid) and polyHIPE-g- poly(lysine). Both types of polypeptide-grafted monoliths responded to pH by changes in their hydrohilicity. The possibility to use the high density of function (−COOH or −NH2) for secondary reaction was demonstrated by the successful bioconjugation of enhanced green fluorescent protein (eGFP) and fluorescein isocyanate (FITC) on the polymer 3D-scaffold surface. The amount of eGFP and FITC conjugated to the polypeptide-grafted polyHIPE was significantly higher than to the amino- functional polyHIPE, signifying the advantage of polypeptide grafting to achieve highly functional polyHIPEs

Sperm Chromatin-Induced Ectopic Polar Body Extrusion in Mouse Eggs after ICSI and Delayed Egg Activation

Meiotic chromosomes in an oocyte are not only a maternal genome carrier but also provide a positional signal to induce cortical polarization and define asymmetric meiotic division of the oocyte, resulting in polar body extrusion and haploidization of the maternal genome. The meiotic chromosomes play dual function in determination of meiosis: 1) organizing a bipolar spindle formation and 2) inducing cortical polarization and assembly of a distinct cortical cytoskeleton structure in the overlying cortex for polar body extrusion. At fertilization, a sperm brings exogenous paternal chromatin into the egg, which induces ectopic cortical polarization at the sperm entry site and leads to a cone formation, known as fertilization cone. Here we show that the sperm chromatin-induced fertilization cone formation is an abortive polar body extrusion due to lack of spindle induction by the sperm chromatin during fertilization. If experimentally manipulating the fertilization process to allow sperm chromatin to induce both cortical polarization and spindle formation, the fertilization cone can be converted into polar body extrusion. This suggests that sperm chromatin is also able to induce polar body extrusion, like its maternal counterpart. The usually observed cone formation instead of ectopic polar body extrusion induced by sperm chromatin during fertilization is due to special sperm chromatin compaction which restrains it from rapid spindle induction and therefore provides a protective mechanism to prevent a possible paternal genome loss during ectopic polar body extrusion

Dynamics of notch pathway expression during mouse testis post-natal development and along the spermatogenic cycle

Articles in International JournalsThe transcription and expression patterns of Notch pathway components (Notch 1–3, Delta1 and 4, Jagged1) and effectors (Hes1, Hes2, Hes5 and Nrarp) were evaluated (through RT-PCR and IHC) in the mouse testis at key moments of post-natal development, and along the adult spermatogenic cycle. Notch pathway components and effectors are transcribed in the testis and expressed in germ, Sertoli and Leydig cells, and each Notch component shows a specific cell-type and timewindow expression pattern. This expression at key testis developmental events prompt for a role of Notch signaling in prepubertal spermatogonia quiescence, onset of spermatogenesis, and regulation of the spermatogenic cycle

Dicer1 Depletion in Male Germ Cells Leads to Infertility Due to Cumulative Meiotic and Spermiogenic Defects

Background: Spermatogenesis is a complex biological process that requires a highly specialized control of gene expression. In the past decade, small non-coding RNAs have emerged as critical regulators of gene expression both at the transcriptional and post-transcriptional level. DICER1, an RNAse III endonuclease, is essential for the biogenesis of several classes of small RNAs, including microRNAs (miRNAs) and endogenous small interfering RNAs (endo-siRNAs), but is also critical for the degradation of toxic transposable elements. In this study, we investigated to which extent DICER1 is required for germ cell development and the progress of spermatogenesis in mice.Principal Findings: We show that the selective ablation of Dicer1 at the early onset of male germ cell development leads to infertility, due to multiple cumulative defects at the meiotic and post-meiotic stages culminating with the absence of functional spermatozoa. Alterations were observed in the first spermatogenic wave and include delayed progression of spermatocytes to prophase I and increased apoptosis, resulting in a reduced number of round spermatids. The transition from round to mature spermatozoa was also severely affected, since the few spermatozoa formed in mutant animals were immobile and misshapen, exhibiting morphological defects of the head and flagellum. We also found evidence that the expression of transposable elements of the SINE family is up-regulated in Dicer1-depleted spermatocytes.Conclusions/Significance: Our findings indicate that DICER1 is dispensable for spermatogonial stem cell renewal and mitotic proliferation, but is required for germ cell differentiation through the meiotic and haploid phases of spermatogenesis