Long-term temporal analysis of four Pyrenean catchments with a gradient of land-cover

<p>Land cover and historical land use practices are the leading drivers of the hydrological response in most catchments systems. Timing, periodicity and magnitude of precipitation-discharge feedbacks are thus impacted by such site-specific characteristics. We analysed the long-term precipitation and discharge databases of four experimental catchments located in the Central Spanish Pyrenees and thus similar in their climate. Furthermore, they have a gradient of land cover (from a relatively pristine forested catchment, through an abandoned cultivated catchment with progressive plant recolonization, to an afforested catchment and ending by a bare degraded badland catchment); so, form a solid benchmark to assess such dynamic changes. For the analysis of the long-term precipitation and discharge time-series we use the wavelet transform methodology, which proves valuable to segregate the continuous hydrological response of the catchments in different and non-similar dominant time-scales. Precipitation and discharge events are not just identified and analysed in terms of magnitude or correlation relationships but also the time-localization of each transient precipitation and discharge events is retrieved. We thus no impose any fixed periodicity in the occurrence of hydrological events and ultimately, we are able to infer the real and site-specific temporal variability of each dataset through which we can infer the timing, variability and physical mechanisms of water storage/transport in each catchment. Thereby, this analysis reveals the land-cover-discharge feedbacks that takes place at different time-scales.</p>

Spontaneous plant recolonization on reclaimed post-coal mining sites in East Kalimantan, Indonesia: Native versus alien and succession progress

Hapsari L, Trimanto, Budiharta S. 2020. Spontaneous plant recolonization on reclaimed post-coal mining sites in East Kalimantan, Indonesia: Native versus alien and succession progress. Biodiversitas 21: 2003-2017. Comparative vegetation analyses subjected to recolonization of spontaneous plants were carried out in two post-coal mining reclamation sites, with different ages of reclamation, specifically 9 years old and 17 years old, in Bontang, East Kalimantan. This study aims to determine the spontaneous plant diversity and composition, identify the spontaneous alien plant species invasion (IAS), analyze the underlying micro-climates and soil factors and their association to the spontaneous plant recolonization, also to evaluate the succession progress. Results showed that both reclamation sites have undergone some vegetation and environmental improvements. The plant succession stage of both sites was identified at the same stage, as establishment phase of early-succession stage in transition to mid-succession stage. The spontaneous plants were comprised of two layers, i.e. (i) understories include grasses, ferns, lianas, herbs, shrubs and tree seedlings; and (ii) saplings include some of trees and small trees. Plant diversity indices on both sites were in moderate category. At understory layer, the 9-y.o. site was mostly dominated by grass Polytrias indica, whereas the 17-y.o. site was dominated by shrub Asystasia gangetica. At sapling layer, the 9-y.o. site was mostly dominated by Glochidion obscurum, whereas the 17-y.o. site was dominated by Macaranga tanarius. Dominant pioneer tree and shrub species in two reclamation sites mostly from general species component of secondary tropical forests from the families Euphorbiaceae, Phyllantaceae, Melastomaceae, Leguminosae, and Lamiaceae. It was recorded seven IAS in the 9-y.o. site, which six out of seven species were dominant. Meanwhile, in the 17-y.o. site was recorded eight IAS but only four species were dominant. Two dominant noxious weed species were also identified. Each IAS and noxious weed species has invasiveness traits that make them well-grown, successfully recolonized and invaded the reclamation site. Environmental factors include air temperature, air moisture, and light intensity; and soil conditions include pH, C/N ratio and physicochemical properties affected the variation of spontaneous plant establishment on each reclamation site. These comparative study findings may become inputs for coal mining operations management to evaluate and improve their reclamation program; such as by soil reconditions, controlling the populations of IAS, and planting more intensively of native tree species.

Aquatic Angiosperm Transplantation: A Tool for Environmental Management and Restoring in Transitional Water Systems

Since the 1960s, the Venice Lagoon has suffered a sharp aquatic plant constriction due to eutrophication, pollution, and clam fishing. Those anthropogenic impacts began to decline during the 2010s, and since then the ecological status of the lagoon has improved, but in many choked areas no plant recolonization has been recorded due to the lack of seeds. The project funded by the European Union (LIFE12 NAT/IT/000331-SeResto) allowed to recolonize one of these areas, which is situated in the northern lagoon, by widespread transplantation of small sods and individual rhizomes. In-field activities were supported by fishermen, hunters, and sport associations; the interested surface measured approximately 36.6 km2. In the 35 stations of the chosen area, 24,261 rhizomes were transplanted during the first year, accounting for 693 rhizomes per station. About 37% of them took root in 31 stations forming several patches that joined together to form extensive meadows. Plant rooting was successful where the waters were clear and the trophic status low. But, near the outflows of freshwater rich in nutrients and suspended particulate matter, the action failed. Results demonstrate the effectiveness of small, widespread interventions and the importance of engaging the population in the recovery of the environment, which makes the action economically cheap and replicable in other similar environments.

Rapid wastage of the Hazen Plateau ice caps, northeastern Ellesmere Island, Nunavut, Canada

Two pairs of small stagnant ice bodies on the Hazen Plateau of northeastern Ellesmere Island, the St. Patrick Bay ice caps and the Murray and Simmons ice caps, are rapidly shrinking, and the remnants of the St. Patrick Bay ice caps are likely to disappear entirely within the next 5 years. Vertical aerial photographs of these Little Ice Age relics taken during August of 1959 show that the larger of the St. Patrick Bay ice caps had an area of 7.48 km2 and the smaller one 2.93 km2; the Murray and Simmons ice caps covered 4.37 and 7.45 km2 respectively. Outlines determined from ASTER satellite data for July 2016 show that, compared to 1959, the larger and the smaller of the St. Patrick Bay ice caps had both been reduced to only 5 % of their former area, with the Murray and Simmons ice caps faring better at 39 and 25 %, likely reflecting their higher elevation. Consistent with findings from other glaciological studies in the Queen Elizabeth Islands, ASTER imagery in conjunction with past GPS surveys documents a strikingly rapid wastage of the St. Patrick Bay ice caps over the last 15 years. These two ice caps shrank noticeably even between 2014 and 2015, apparently in direct response to the especially warm summer of 2015 over northeastern Ellesmere Island. The well-documented recession patterns of the Hazen Plateau ice caps over the last 55+ years offer an opportunity to examine the processes of plant recolonization of polar landscapes.

Rapid Wastage of the Hazen Plateau Ice Caps, Northeastern Ellesmere Island, Nunavut, Canada

Two pairs of small stagnant ice bodies on the Hazen Plateau of northeastern Ellesmere Island, the St. Patrick Bay ice caps and the Murray and Simmons ice caps, are rapidly shrinking, and the remnants of the St. Patrick Bay ice caps are likely to disappear entirely within the next five years. Vertical aerial photographs of these Little Ice Age relics taken during August of 1959 show that the larger of the St. Patrick Bay ice caps had an area of 7.48 km2, and the smaller one 2.93 km2. The Murray and Simmons ice caps covered 4.37 km2 and 7.45 km2 respectively. Outlines determined from ASTER satellite data for July 2016 show that, compared to 1959, the larger and the smaller of the St. Patrick Bay ice caps had both been reduced to only 5 % of their former area, with the Murray and Simmons ice caps faring better at 39 % and 25 %, likely reflecting their higher elevation. ASTER imagery in conjunction with past GPS surveys documents a strikingly rapid wastage of the St. Patrick Bay ice caps over the last 15 years. These two ice caps shrank noticeably even between 2014 and 2015, apparently in direct response to the especially warm summer of 2015 over northeastern Ellesmere Island. The well-documented recession patterns of the Hazen Plateau ice caps over the last 55+ years offer an opportunity to examine the processes of plant recolonization of polar landscapes.

Fate and Persistence of Long-Term Spilled Metula Oil in the Marine Salt Marsh Environment: Degradation of Petroleum Biomarkers

ABSTRACT Complete “total oil analyses” were performed on the 24-year-old spilled Metula oil samples collected during the 1998 field visit. Fingerprinting data clearly indicate, except those three samples collected from the East Marsh untreated plots (EE-GO, EE-CI and EE-C2) that were only moderately weathered, the spilled oil has undergone significant alteration in chemical composition after 24 years. There are no fundamental differences between heavily weathered and degraded West Marsh and treated East Marsh samples. However, the effect of the experimental tilling action has been to promote plant recolonization. This result indicates that the recolonization of the marshes almost certain would have been accelerated had tilling or mixing been conducted on these sites after the spill. Chemical analyses of the two asphalt pavement samples (WI-1 and WI-2) indicate extremely heavy degradation. For these two samples, complete spectrum of n-alkanes from C8 to C40 and greater than 98% of alkylated PAH homologues were lost, and even the highly biodegradation-resistant biomarker compounds were shown to be more or less altered. It is observed that biomarkers were generally degraded in the declining order of importance as follows: diasteranes > C27 steranes > tricyclic terpanes > pentacyclic terpanes > norhapanes ∼C29 αββ steranes.