Changes in the Physico-Chemical Properties of Degraded Soils in Response to the ReviTec Approach Applied at Gawel (Far-North Cameroon)

A heavily degraded hardé area in the community of Gawel (Extreme Nord) was rehabilitated with a ReviTec approach. To evaluate the efficiency of introduced plants for rehabilitation, the site was monitored with the BioSoilPlot experiment over two years during the dry and rainy seasons (January 2018/2019, June 2018/2019, respectively). ReviTec was applied to accelerate ecological succession and improve the establishment of vegetation on these degradation-prone sites (Gawel 1 and Gawel 2). Growth volume, height and percentage cover of the herbaceous plants and soil physical and chemical parameters were assessed. Growth volume increased in both sites between 2018 and 2019 with Pennisetum pedicellatum exhibiting the highest values (Gawel 1: 3.41 dm3/m2 and 3.50 dm3/m2; Gawel 2: 3.47 dm3/m2 and 3.62 dm3/m2). Bunds were suitable for herbaceous growth, Sesbania sesban having the highest growth height (Gawel 1: 1.91 cm and 1.95 cm; Gawel 2: 1.95 cm and 1.97 cm) and Pennisetum pedicellatum the best percentage cover (Gawel 1: 53% and 58.33%; Gawel 2: 40.67% and 56.67%). Soil changed from sandy and strongly acid to clay-loam and slightly acid at Gawel 1, and from sandy and strongly acid to clay-loam and alkaline at Gawel 2. Soil water content and soil nutrient had increased within the ReviTec site compared to the outside with the application of compost-biochar-mycorrhiza treatment as the most promising over the two years of monitoring. Such results suggest that ReviTec approach can be used in sustainable restoration of soil hardé.

The Nature, Extent and Survivorship of Biofouling Organisms at Different Hull Locations on Various Vessel Types

<p><b>The importance of vessel biofouling as a vector for the dispersal of non-indigenousmarine species (NIMS) is only just beginning to receive international attention. At thetime of commencing this study, there was a considerable lack of knowledge surroundingwhich vessels, hull locations, levels and types of biofouling pose the greatestbiosecurity risk. Therefore, the aim of this study was to investigate the nature, extentand survivorship of biofouling organisms on various vessel types at different hulllocations and offers a pragmatic risk assessment approach for managing this threat.</b></p> <p>The results of this thesis found that the recruitment, persistence, distribution, abundanceand species composition of biofouling on vessel hulls is influenced by many factorsincluding: 1) the presence/absence, age and type of anti-fouling coating; 2) voyageduration and route; and 3) port residency period. Therefore, higher levels of biofouling(species richness, percentage cover, and biomass), including NIMS are more likely toaccumulate and persist on vessels (and in hull locations) that: 1) lack and/or possess old,ineffective, damaged, inappropriate or unsuitable anti-fouling coatings; 2) spendprolonged periods stationary in ports; 3) travel at slow speeds (i.e. <10 knots); 4) haveshort voyage durations; and 5) remain at similar latitudes.</p> <p>Prevention is clearly better than a cure, hence the correct application and maintenanceof suitable anti-fouling coatings to the entire submerged hull surface of vessel hulls,including niche areas is the most cost-effective way of minimising the unwantedtranslocation of biofouling organisms and NIMS. However, the results of this thesisdemonstrate that if biofouling organisms colonise and establish on a vessel's hull,voyage speed alone is not capable of providing a reliable secondary level of defenceagainst the unwanted dispersal of NIMS. Clearly, the survivorship of biofoulingorganisms was highest amongst vessels that travelled at slow and medium speeds (e.g.</p> <p><10 knots). Therefore, given that accumulation of biofouling follows a successionalprocess and NIMS are more likely to be associated with higher levels of biofouling,vessels that travel at slow and medium speeds are more likely to pose the greatest riskof translocating NIMS on a vessel by vessel scale. However, despite the observationthat faster vessels reduce the diversity, quantity and quality of sessile biofoulingorganisms in laminar flow areas of the hull, a wide range of sessile, sedentary andmobile organisms were still cable of survival in areas protected from harsh hydrodynamically forces commonly referred to as niche areas, particularly within sea-chests.</p>

The Nature, Extent and Survivorship of Biofouling Organisms at Different Hull Locations on Various Vessel Types

<p><b>The importance of vessel biofouling as a vector for the dispersal of non-indigenousmarine species (NIMS) is only just beginning to receive international attention. At thetime of commencing this study, there was a considerable lack of knowledge surroundingwhich vessels, hull locations, levels and types of biofouling pose the greatestbiosecurity risk. Therefore, the aim of this study was to investigate the nature, extentand survivorship of biofouling organisms on various vessel types at different hulllocations and offers a pragmatic risk assessment approach for managing this threat.</b></p> <p>The results of this thesis found that the recruitment, persistence, distribution, abundanceand species composition of biofouling on vessel hulls is influenced by many factorsincluding: 1) the presence/absence, age and type of anti-fouling coating; 2) voyageduration and route; and 3) port residency period. Therefore, higher levels of biofouling(species richness, percentage cover, and biomass), including NIMS are more likely toaccumulate and persist on vessels (and in hull locations) that: 1) lack and/or possess old,ineffective, damaged, inappropriate or unsuitable anti-fouling coatings; 2) spendprolonged periods stationary in ports; 3) travel at slow speeds (i.e. <10 knots); 4) haveshort voyage durations; and 5) remain at similar latitudes.</p> <p>Prevention is clearly better than a cure, hence the correct application and maintenanceof suitable anti-fouling coatings to the entire submerged hull surface of vessel hulls,including niche areas is the most cost-effective way of minimising the unwantedtranslocation of biofouling organisms and NIMS. However, the results of this thesisdemonstrate that if biofouling organisms colonise and establish on a vessel's hull,voyage speed alone is not capable of providing a reliable secondary level of defenceagainst the unwanted dispersal of NIMS. Clearly, the survivorship of biofoulingorganisms was highest amongst vessels that travelled at slow and medium speeds (e.g.</p> <p><10 knots). Therefore, given that accumulation of biofouling follows a successionalprocess and NIMS are more likely to be associated with higher levels of biofouling,vessels that travel at slow and medium speeds are more likely to pose the greatest riskof translocating NIMS on a vessel by vessel scale. However, despite the observationthat faster vessels reduce the diversity, quantity and quality of sessile biofoulingorganisms in laminar flow areas of the hull, a wide range of sessile, sedentary andmobile organisms were still cable of survival in areas protected from harsh hydrodynamically forces commonly referred to as niche areas, particularly within sea-chests.</p>

The role of land use and morphology representation in the setup and calibration of the conceptual TUW model

The processes of the transformation of rainfall to runoff are highly complicated, and the proper characterisation of these processes with conceptual hydrological models is a very challenging task. Morphology and land cover have a significant influence on a river basin’s hydrologic response. Thus, catchment characteristics of the topography and land use play an essential role in parametrising the runoff concentration processes in hydrological models. In the study, our goal was to detect which characteristics and their spatial distribution influence the efficiency of a conceptual rainfall-runoff model efficiency most. The spatially lumped and semi-distributed versions of the TUW conceptual rainfall model, which is an HBV type model, were compared. Both models use the concept of lumped storages associated with the surface and subsurface, interconnected by thresholds and links to simulate the runoff transformation. We focused on two land-use characteristics, the percentage cover of the agricultural land and percentage cover of the forests, and the mean slope of the terrain as a topography characteristic. The differences between runoff model efficiencies both in the calibration and validation periods were evaluated. Based on which version of the model was more effective in the simulation of the runoff, it was detected which types of catchment land use, and morphology were better represented by using the lumped or semi-distributed version of the TUW model, respectively. The analysis aimed to improve the understanding of the influence of spatial representation morphology and land cover in conceptual models on model efficiency and may help to improve model setup and calibration.

Effects of Natural and Anthropogenic Stressors on Fucalean Brown Seaweeds Across Different Spatial Scales in the Mediterranean Sea

Algal habitat-forming forests composed of fucalean brown seaweeds (Cystoseira, Ericaria, and Gongolaria) have severely declined along the Mediterranean coasts, endangering the maintenance of essential ecosystem services. Numerous factors determine the loss of these assemblages and operate at different spatial scales, which must be identified to plan conservation and restoration actions. To explore the critical stressors (natural and anthropogenic) that may cause habitat degradation, we investigated (a) the patterns of variability of fucalean forests in percentage cover (abundance) at three spatial scales (location, forest, transect) by visual estimates and or photographic sampling to identify relevant spatial scales of variation, (b) the correlation between semi-quantitative anthropogenic stressors, individually or cumulatively (MA-LUSI index), including natural stressors (confinement, sea urchin grazing), and percentage cover of functional groups (perennial, semi-perennial) at forest spatial scale. The results showed that impacts from mariculture and urbanization seem to be the main stressors affecting habitat-forming species. In particular, while mariculture, urbanization, and cumulative anthropogenic stress negatively correlated with the percentage cover of perennial fucalean species, the same stressors were positively correlated with the percentage cover of the semi-perennial Cystoseira compressa and C. compressa subsp. pustulata. Our results indicate that human impacts can determine spatial patterns in these fragmented and heterogeneous marine habitats, thus stressing the need of carefully considering scale-dependent ecological processes to support conservation and restoration.

MULTIVARIATE MULTIVARIATE ANALYSIS OF WEEDS OF CHICKPEA, MUSTARD AND WHEAT CROP FIELDS OF TEHSIL ISAKHEL, DISTRICT MIANWALI (PUNJAB), PAKISTAN

Multivariate analysis through Two Way Indicator Species Analysis (TWINSPAN) was conducted to study the phytosociological attributes of weeds of some selected crop fields of chickpea, mustard and wheat of Tehsil Isa Khel, District Mianwali, Punjab. Forty one (41) weed species were collected from the study area belonging to twenty one (21) different families. Twenty four weed species found in chickpea, twenty five in mustard and twenty nine in wheat crop fields. Sixteen weed species were common in three crops. Family Poaceae and Astraceae had maximum weed species i.e. 7 and 6 species respectively followed by Euphorbiaceae, Fabaceae, Chenopodiaceae, Papaveraceae, Zygophyllaceae and so on. Asphodelus tenuifolius, Medicago monantha and Carthamus oxycantha are frequently occurring weeds relative to others. Two-Way Indicator Species Analysis (TWINSPAN) was performed on the percentage cover basis which divided the weed species into groups, sub groups, associations and sub associations.

Interannual variability and decadal stability of benthic organisms on an Indonesian coral reef

The availability of colonizable substrate is an important driver of the temporal dynamics of sessile invertebrates on coral reefs. Increased dominance of algae and, in some cases, sponges has been documented on many coral reefs around the world, but how these organisms benefit from non-colonized substrate on the reef is unclear. In this study, we described the temporal dynamics of benthic organisms on an Indonesian coral reef across two time periods between 2006 and 2017 (2006–2008 and 2014–2017), and investigated the effects of colonizable substrate on benthic cover of coral reef organisms at subsequent sampling events. In contrast with other Indonesian reefs where corals have been declining, corals were dominant and stable over time at this location (mean ± SE percentage cover 42.7 ± 1.9%). Percentage cover of turf algae and sponges showed larger interannual variability than corals and crustose coralline algae (CCA) (P < 0.001), indicating that these groups are more dynamic over short temporal scales. Bare substrate was a good predictor of turf cover in the following year (mean effect 0.2, 95% CI: 0–0.4). Algal cover combined with bare space was a good predictor of CCA cover the following year generally, and of sponge cover the following year but only at one of the three sites. These results indicate that turf algae on some Indonesian reefs can rapidly occupy free space when this becomes available, and that other benthic groups are probably not limited by the availability of bare substrate, but may overgrow already fouled substrates.

Natural Productivity, Morphometrics and Seasonal Distribution of Caulerva Racemosa

Caulerva racemosa seaweed is a superior commodity with both ecological and socio-economical benefits. It is technologically developed into different products which include antioxidants, antibiotics, medicinal ingredients, cosmetics as well as other organic products and also used conventionally as food ingredients for human’s consumption. Meanwhile, the presence of C. racemosa is observed to decrease as the exploitation rate is one of the factors affecting its stock in the nature. Changes in environmental conditions contribute majorly to its availability in aquatic ecosystems. Furthermore, natural factors in the form of seasonal changes that cause fluctuations in water dynamics are the main focus affecting its lifespan. The results showed that C. racemosa growth parameters, which include percentage cover, productivity, together with morphometrics, failed to be significantly affected by seasonal changes. Meanwhile, the highest percentage cover was found during the northern monsoon, which has an average value of 37.99 ± 7.67 (Average±STDEV), while the lowest was during the eastern monsoons with 28.03 ± 9.09 respectively. The best morphometric size was during the northern monsoon with a tallus dimension of 0.25 with an average of 0.201 ± 0.03 and length of 0.825 ± 0.16, a stolon length of 2.09 with an average of 1.95 ± 0.08, 9 stolon grains with an average of 8 ± 0.2. However, the grain diameter, as well as the biomass, was 0.85 gr and 0.054 gr with an average of 0.825 ± 0.22 gr and the grain biomass was with an average of 0.040 ± 0.01 and 0.041 gr with the best average stolon was 0.031 ± 0.01 g in the western season. The results showed that C. racemosa, which grows up in different seasons, having its highest productivity during the northern season and the lowest one was during the eastern season with an average value of 0.439 ± 0.36 kg/m2 as well as 0.326 ± 0.37 Kg/m2, respectively

Loss of Dugong Grass [Halophila Ovalis (R. Brown)] Population Structure Due to Habitat Disturbance in an Island Ecosystem

Seagrass ecosystems are lost due to habitat disturbance, coastal development and human pressure. We assessed the impact of boat anchors from traditional fishing and recreational activities on the seagrass Halophila ovalis from the Andaman and Nicobar Isalnds of India. The plant density, biomass, morphometrics, canopy height and percentage cover were estimated from two sites of Govind Nagar beach of Andaman and Nicobar Islands. The shoot density of H. ovalis was reduced by physical damage caused by boat anchors. The morphometrics of H. ovalis, such as number of leaves per ramet, leaf length, width and horizontal rhizome length were significantly reduced when impacted by boat anchors. Seagrass canopy height and percentage cover were reduced by 41% and 47% respectively. Though the impact of boat anchors reported here is on small-scale, it may impact feeding grounds of locally endangered dugongs. Therefore, proper management and preventive measures should be implemented to prevent the loss of dugong grass habitats from tourism, recreational and fishing activities.