Land tenure and REDD+: The good,the bad and the ugly     

Anne M. Larson  Maria Brockhaus  William D. Sunderlin  Amy Duchelle  Andrea Babon  Therese Dokken  Thu Thuy Pham  I.A.P. Resosudarmo  Galia Selaya  Abdon Awono  Thu-Ba Huynh 《Global Environmental Change》2013,23(3):678-689

A number of international donors, national governments and project proponents have begun to lay the groundwork for REDD+, but tenure insecurity – including the potential risks of land grabbing by outsiders and loss of local user rights to forests and forest land – is one of the main reasons that many indigenous and other local peoples have publicly opposed it. Under what conditions is REDD+ a threat to local rights, and under what conditions does it present an opportunity? This article explores these issues based on available data from a global comparative study on REDD+, led by the Center for International Forestry Research, which is studying national policies and processes in 12 countries and 23 REDD+ projects in 6 countries. The article analyses how tenure concerns are being addressed at both national and project level in emerging REDD+ programs. The findings suggest that in most cases REDD+ has clearly provided some new opportunities for securing local tenure rights, but that piecemeal interventions by project proponents at the local level are insufficient in the absence of broader, national programs for land tenure reform. The potential for substantial changes in the status quo appear unlikely, though Brazil – the only one with such a national land tenure reform program – offers useful insights. Land tenure reform – the recognition of customary rights in particular – and a serious commitment to REDD+ both challenge the deep-rooted economic and political interests of ‘business as usual’.  相似文献   

Detailed spatio‐temporal sediment supply reconstruction using tree roots data          下载免费PDF全文

Karel Šilhán  Tomáš Galia  Václav Škarpich 《水文研究》2016,30(22):4139-4153

Floods are an important geomorphic agent that accelerate sediment supply from bank failures. The quantitative proportions supplied by lateral inputs and the transport conditions of the channel can create local or extended accumulation zones within the channel reaches. These accumulation zones play an important role in the geomorphic regime of the stream. Knowledge of long‐term history of sediment supply is necessary to determine how these input and deposition forms developed. This study introduces a new approach for the quantification of past sediment supply via lateral erosion (incised banks and individual bank failures), using a case study of the confluence of three partial tributaries in the accumulation zone in the Outer Western Carpathians. For each tributary, as well as the channel reach downstream of the confluence zone, we calculated the mean of the largest bed particles and the unit stream power as indicators of transport capacity. We found that two of the tributaries supply significant amounts of sediment to the accumulation zone because of their higher unit stream power related to their higher transport potential, and observed coarser bed sediment. Seventy‐three bank failures with a total volume 395.5 m³ were mapped, and the sediment supply volume was dated using dendrogeomorphic analysis of 114 scarred tree roots (246 samples). The total volume of the dated sediment supply in the individual tributaries was 193.9 m³, whereas the volume of erosion in the accumulation zone was only 4.9 m³ for a period of approximately 30 years. The period represented by the dated tree roots included 12 years in which erosion events occurred and impacted the total sediment budget in the study area. Although sediment supply was greater than erosion in the accumulation zone, there are no present‐day signs of accretion. The rupture of a dam in an old pond (which is situated approximately 50 m below the accumulation zone) probably increased the transport conditions in the accumulation zone so that it balanced the high sediment supply from individual tributaries. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

The 2005 eruption of Ilamatepec (Santa Ana) volcano,El Salvador     

Teresa Scolamacchia  Carlos Pullinger  Lizeth Caballero  Francisco Montalvo  Laura E. Beramendi Orosco  Galia Gonzalez Hernández 《Journal of Volcanology and Geothermal Research》2010,189(3-4):291-318

We report the stratigraphic sequence of the 2005 eruption of Ilamatepec volcano together with sedimentological and chemical analyses of its products.Structural and textural characteristics of the deposits indicate that the eruption was driven by a small-volume rhyolitic intrusion at shallow levels, which resulted first in the collapse of the existing hydrothermally altered fan of previous deposits inside the crater lake, driving phreatic explosions with launching of blocks on ballistic trajectories; later the magma interacted with lake waters producing several hydromagmatic pyroclastic density currents (PDCs). These flows were energetic enough to knock down pine trees up to distances of 1.8 km from the crater in the E-NE sector of the volcano. Finally, ejection of ballistic blocks that landed on previously emplaced, wet pyroclastic density current deposits, caused the generation of a lahar that flowed down the steep eastern flank toward the El Jabillal gully. Subsequent lahars occurred as a result of intense rain caused by hurricane Stan.Radiocarbon ages on paleosols and charcoal fragments, separating previous volcanogenic sequences, indicate that similar eruptions have occurred more frequently in the past centuries, than previously thought.The new data confirms that Ilamatepec volcano is one of the most active volcanoes in El Salvador. Nevertheless, more detailed studies of the eruptive sequence of Ilamatepec volcano are mandatory to establish future eruptive patterns.  相似文献   

Drivers of variability in large wood loads along the fluvial continuum of a Mediterranean intermittent river     

Tomáš Galia  Tereza Macurová  Leonidas Vardakas  Václav Škarpich  Tereza Matušková  Eleni Kalogianni 《地球表面变化过程与地形》2020,45(9):2048-2062

Although in-channel and floodplain large wood (LW) has been recognized as an important component of lotic ecosystems, there is still limited knowledge on the recruitment, mobility and retention of LW in rivers with an intermittent hydrological regime. In this study, we analysed the LW characteristics and related reach-scale variables of 22 reaches in a Mediterranean intermittent river (Evrotas, Greece) in order to identify predictors of in-channel and floodplain LW distribution. Our results indicated high downstream variation in LW volumes in the fluvial corridor (0.05–25.51 m³/ha for in-channel LW and 0–30.88 m³/ha for floodplain LW). In-channel and floodplain LW retention was primarily driven by the hydrological regime of the studied reaches (i.e. perennial or non-perennial) with higher volumes of LW observed in perennial sections. The width of the riparian corridor was an important predictor of LW storage at the reach scale. Non-perennial reaches had a disproportionally larger number of relatively small-diameter living trees at the expense of mature trees with larger diameters typical for riparian stands functioning as LW recruitment areas in perennial reaches. The smaller dimensions of in-channel LW in non-perennial reaches, coupled with the dominance of loose LW pieces, implies frequent LW transport during ordinary flood events. Nevertheless, overall low LW retention in the fluvial corridor under non-perennial flow regime predicts low volumes of mobilized LW. In contrast, the recruitment of relatively long and large-diameter LW from mature riparian stands in perennial reaches, together with additional LW stabilization by banks, bed sediments, living trees or other LW pieces decreases the potential for further LW transport. © 2020 John Wiley & Sons, Ltd.  相似文献   

High-resolution chronology for the Mesoamerican urban center of Teotihuacan derived from Bayesian statistics of radiocarbon and archaeological data     

Laura E. Beramendi-Orosco  Galia Gonzalez-Hernandez  Linda R. Manzanilla  Avto Goguitchaishvili 《Quaternary Research》2009,71(2):99-107

A high-resolution ¹⁴C chronology for the Teopancazco archaeological site in the Teotihuacan urban center of Mesoamerica was generated by Bayesian analysis of 33 radiocarbon dates and detailed archaeological information related to occupation stratigraphy, pottery and archaeomagnetic dates. The calibrated intervals obtained using the Bayesian model are up to ca. 70% shorter than those obtained with individual calibrations. For some samples, this is a consequence of plateaus in the part of the calibration curve covered by the sample dates (2500 to 1450 ¹⁴C yr BP). Effects of outliers are explored by comparing the results from a Bayesian model that incorporates radiocarbon data for two outlier samples with the same model excluding them. The effect of outliers was more significant than expected. Inclusion of radiocarbon dates from two altered contexts, 500 ¹⁴C yr earlier than those for the first occupational phase, results in ages calculated by the model earlier than the archaeological records. The Bayesian chronology excluding these outliers separates the first two Teopancazco occupational phases and suggests that ending of the Xolalpan phase was around cal AD 550, 100 yr earlier than previously estimated and in accordance with previously reported archaeomagnetic dates from lime plasters for the same site.  相似文献   

Connectivity of the Coarsest Fraction in Headwater Channels: Imprints of Fluvial Processes and Debris‐Flow Activity          下载免费PDF全文

Tomáš Galia  Václav Škarpich  Jan Hradecký 《Geografiska Annaler: Series A, Physical Geography》2015,97(3):437-452

Some steep headwater streams of the mid‐mountains landscape of the flysch belt of the Western Carpathians are affected by debris flows. Connectivity of the largest boulder and cobble fractions has been evaluated in steep streams found in the transitional zones between the hillslopes and alluvial cones of similar lithology and watershed morphometry. Two longitudinal profiles affected by past debris‐flow activity and two longitudinal profiles void of such processes were selected. In the first case, active channels were characterised by the presence of the coarsest fraction, while a downstream trend of sediment coarsening or fining lacked any influence of contemporary fluvial processes and sediment supply. In addition, debris‐flow‐affected streams showed greater differences between the middle axis of the coarsest particle and the particle‐size index including the lengths of all three axes, which is most likely the result of limited active fluvial transport. All the studied streams demonstrated general downstream fining of the largest particles, which resulted from local flysch lithology containing more resistant sandstones in the upper parts of the watershed. The trend of sediment fining was more rapid in the longitudinal profiles unaffected by past debris flows. These types of streams also showed adjustment of the coarsest bed fraction to contemporary processes in channels by sediment coarsening in incised reaches and sediment fining in depositional reaches as well as by downstream response to some lateral sediment inputs. The index of the unit stream power showed no correlation with the considered coarsest fraction in both fluvial‐dominated channels and debris‐flow‐affected channels.  相似文献   

Rock‐Magnetic and Archaeointensity Investigation of Pottery and a Burned Floor at the Tzintzuntzan Archaeological Site,Western Mexico     

Juan Morales  Avto Goguitchaichvili  Bertha A. Aguilar‐Reyes  Modesto Pineda  Claire Carvallo  Laura Beramendi‐Orosco  Galia Gonzlez‐Hernndez  Arturo Oliveros 《Geoarchaeology》2012,27(6):521-537

We report a detailed rock‐magnetic and archaeointensity analysis of four pottery fragments and a burned floor recovered from the Tzintzuntzan archaeological site in western Mexico. Results from rock‐magnetic experiments (x‐T curves and first‐order reversal curves [FORC] diagrams) indicate the suitability of most of these materials as faithful geomagnetic field recorders. Potsherds were archaeomagnetically dated by comparing their mean intensity values against the paleosecular variation curve CALS3k, suggesting A.D. 600–941 as the most probable age range. This is younger than ¹⁴C‐dated charcoal from the same burned floor (A.D. 1294–1426). More precise age estimates will require the use of the full geomagnetic vector (declination, inclination, and intensity). Multiple reheatings of the ceramic pieces, evidenced as secondary components in Zijderveld plots, could reflect multiple heating of these objects, perhaps from use as incense burners. Our study demonstrates the potential of archaeomagnetic analysis to both date burned ceramics recovered in situ and provide insight into their use‐history.  相似文献