Endogenous Berber Forest Management and the Functional Shaping of Rural Forests in Southern Morocco: Implications for Shared Forest Management Options

On the basis of two case studies in rural Morocco, one in a mountainous area of the Central High Atlas and the other in the argan tree area of the southwest Atlantic coast, we show how local Berber populations have actively shaped their forest areas through endogenous management systems at different scales: 1) at the individual tree level by differential cutting or trimming which lead to specific conformations of the tree, 2) at the tree stand level, by determining the type, structure and level of resources, and 3) at the landscape level in which complementary patches of forest areas with particular functions are consciously organized within the overall territory. These practices are strongly linked with the overall socioeconomic organization of the local communities, and mix individual with common rights of access and uses. Forests are viewed as part of the domestic sphere of local livelihoods. Hence, they typically constitute what we refer to as rural or domestic forests since they integrate production and conservation with social, political and spiritual dimensions. These features are of importance for considering forester-local community relationships, and for developing alternative forest management policies.     

Temperature effects on anaerobic fermentation of domestic refuse

Anaerobic fermentation of organic solid waste can provide a significant source of fuel gas (methane). Application of this process requires a better understanding of the kinetics of the biological system. The literature is replete with kinetic studies of this process as applied to waste solids from water pollution control systems. Much of this work has been conducted in the mesophilic temperature range. Increased temperatures yield higher reaction rates that will improve the economics of the process. The rate limiting step in the fermentation of refuse is the hydrolysis of the complex organic solids, in particular cellulose. Cellulose is a major component of the refuse. A laboratory study employing domestic refuse has shown the effect of temperature on the rate of methane fermentation. The optimum mesophilic temperature was found to be 42°C, while the optimum thermophilic temperature was at least 60°C. No data was obtained beyond the 60°C temperature. Reaction rate constants are presented for anaerobic fermentation of domestic refuse. Because of the characteristics of the substrate it^?was not possible to obtain the necessary measurements for evaluation of constants in the Monod model. An overall system constant was developed.     

Assessing Herbivory Rates of Leaf-Cutting Ant (Atta colombica) Colonies Through Short-Term Refuse Deposition Counts

Leaf-cutting ants (genera Atta and Acromyrmex ) are considered dominant herbivores of Neotropical forests. However, so far quantitative, long-term, and large-scale assessments of their impact on these ecosystems are rare, because the available assessment methods were laborious and/or destructive. We describe a rapid, nondestructive, and inexpensive method to estimate the long-term harvest of Atta colombica colonies. Workers of A. colombica dump the colony refuse (exhausted fungal substrate) outside the nest. A single trail connects the refuse pile and the nest. In contrast to the foraging activity, the refuse deposition rate (the number of deposited refuse particles per minute) is diurnally constant and varies little on subsequent days. The number of refuse particles deposited per day was tightly correlated with the number of harvested fragments in nests of differing sizes ( R ²= 0.77, P < 0.0001). Therefore, the daily harvest of a particular colony can be calculated from short-term counts (5 min) of the refuse deposition rate at any time of the day. Combining these data with information on average fragment size (weight and/or area) allows the calculation of the total daily amount of biomass and/or foliage area harvested by the colony. This new method facilitates quantifying A. colombica herbivory on scales of populations and ecosystems, or over long-term scales.     

Comparison of Bacteria and Archaea communities in municipal solid waste, individual refuse components, and leachate

Refuse decomposition in landfills is a microbially mediated process that occurs primarily under anaerobic conditions. Because of limited moisture conditions, hydraulic transport as a means of cellular translocation within the landfill appears limited, especially during the initial stages of decomposition. Thus, microbial communities within the incoming refuse serve as a primary source of facultative and obligate anaerobic microorganisms that initiate refuse decomposition. Fresh residential refuse was collected five times over 26 months, and microbial communities in these samples were compared with those in individual refuse components and decomposed refuse. Bacterial and archaeal community structures were determined using T-RFLP. The Bacterial microbial community richness was correlated (r(2) = 0.91) with seasonal differences in ambient air temperature. Analysis of the results shows that fresh refuse is most likely not the source of methanogens in landfills. Microbial communities in the solid and leachate phases were different, indicating that both matrices must be considered when characterizing microbial diversity within a landfill.     

Herbivory Rate of Leaf-Cutting Ants in a Tropical Moist Forest in Panama at the Population and Ecosystem Scales

Leaf-cutting ants are frequently characterized as the major herbivores in the Neotropics, but quantitative data to back up this assumption are scarce. In this study, the consumption and herbivory rates for the entire leaf-cutting ant ( Atta colombica , Formicidae) population in an old secondary forest on Barro Colorado Island (BCI) in Panama were determined over 15 mo (on average 49 colonies). The number of harvested leaf fragments was calculated from monthly refuse deposition rates of the colonies and the regression between refuse deposition and harvesting rates. The inclusion of fragment characteristics (proportion of leaf fragments in the harvest, average fragment weight, and area) allowed us to calculate consumption and herbivory rates at colony, population, and ecosystem levels. The A. colombica population harvested 13.2 tons of biomass/yr and 13.1 ha of leaf area/yr, and deposited 9.4 tons of refuse material/yr. Rates varied considerably among colonies. At the ecosystem level, i.e. , per forest area, herbivory rates were 132 kg biomass/ha/yr and 1310 m² foliage/ha/yr. For the area on BCI where A. colombica occurs (100 ha), this is equivalent to 2.1 percent of the foliage area in the forest or 1.7 percent of the annual leaf-area production. This value is considerably lower than previously published estimates of leaf-cutting ant herbivory rates in tropical forests.     

Cellulose-Enriched Microbial Communities from Leaf-Cutter Ant (Atta colombica) Refuse Dumps Vary in Taxonomic Composition and Degradation Ability

Deconstruction of the cellulose in plant cell walls is critical for carbon flow through ecosystems and for the production of sustainable cellulosic biofuels. Our understanding of cellulose deconstruction is largely limited to the study of microbes in isolation, but in nature, this process is driven by microbes within complex communities. In Neotropical forests, microbes in leaf-cutter ant refuse dumps are important for carbon turnover. These dumps consist of decaying plant material and a diverse bacterial community, as shown here by electron microscopy. To study the portion of the community capable of cellulose degradation, we performed enrichments on cellulose using material from five Atta colombica refuse dumps. The ability of enriched communities to degrade cellulose varied significantly across refuse dumps. 16S rRNA gene amplicon sequencing of enriched samples identified that the community structure correlated with refuse dump and with degradation ability. Overall, samples were dominated by Bacteroidetes, Gammaproteobacteria, and Betaproteobacteria. Half of abundant operational taxonomic units (OTUs) across samples were classified within genera containing known cellulose degraders, including Acidovorax, the most abundant OTU detected across samples, which was positively correlated with cellulolytic ability. A representative Acidovorax strain was isolated, but did not grow on cellulose alone. Phenotypic and compositional analyses of enrichment cultures, such as those presented here, help link community composition with cellulolytic ability and provide insight into the complexity of community-based cellulose degradation.     

Foraging distances of a resident yellow-legged gull (Larus michahellis) population in relation to refuse management on a local scale

Seasonal fluctuations in marine prey availability around breeding colonies are one of the major factors affecting resident behaviour in seabirds. This is particularly applicable to large gulls (Larus spp.). The effect of refuse management on large gulls has been studied chiefly in relation to breeding dynamics, but it is less understood with regard to movement patterns. Our aim was to test whether the closure of one large dump and the use of falconry to deter gull access to two others, within the southeastern Bay of Biscay area, affected the foraging distance of local yellow-legged gulls (Larus michahellis). During a period of seven consecutive winters between 2005 and 2011, the proportion of gulls that moved less than 50 km from their natal site was 70 %. However, during the winter of 2010, when they were deterred from accessing refuse tips within the region, gulls were found to travel longer distances. This result was explained neither by a decreasing survey effort near colonies nor by a decrease in apparent availability of marine prey, thus supporting the hypothesis that refuse management within the region influenced the movement patterns of local gulls.     

Control/promotion of the refuse methanogenic fermentation

Although practiced for more than 7 millennia, the landfill disposal of refuse has, as yet, with few exceptions, been merely regarded as a low-cost disposal option and its exploitation potential has been largely ignored. Today, however, a number of possibilities are under consideration including the production of energy, chemical feedstock, value-added chemicals, carbon dioxide and protein; the use of refuse as an anaerobic filter for the co-disposal of industrial wastewater and sludge; and the restoration of impoverished soils by fresh or composted refuse addition. Development of these technologies, however, necessitates a comprehensive understanding of the fundamental microbiology and biochemistry of refuse catabolism. Existing fundamental knowledge underpinning these technologies will be considered in a series of review articles. In the first, control/exploitation of the solid-state refuse methanogenic fermentation is examined with specific reference to the effects of first-tier variable manipulations.     

Exploitation of a new food source by the Great Skua in Shetland

There are many records of skuasfeeding on domestic refuse in the southern hemisphere, where there is no large gull competitor. The observations reported here document the first indications that Scottish birds may be adopting this scavenging habit.     

Anaerobic digestion of cellulose fraction of domestic refuse by means of rumen microorganisms

The anaerobic digestion of a cellulose-enriched fraction of domestic refuse by means of rumen microorganisms in an "artificial rumen" digester was studied. Various combinations of solid and liquid retention times and loading rates were applied to establish optimum conditions for the acidogenic phase digestion of the refuse fraction. An optimal substrate conversion of about 72% was obtained at a loading rate of 23.4 g volatile solids (VS)/L d and a solids retention time of 90 h. Variation of dilution rate between 1.04 and 3.14 fermentor volume turnovers per day had no effect on degradation efficiency. At a loading rate of 23.4 g VS/L d a differential removal rate of solids and liquids appeared to be necessary to obtain an effective degradation of the refuse fraction.     

Double-stranded DNA organization in bacteriophage heads: an alternative toroid-based model.

Studies of the organization of double-stranded DNA within bacteriophage heads during the past four decades have produced a wealth of data. However, despite the presentation of numerous models, the true organization of DNA within phage heads remains unresolved. The observations of toroidal DNA structures in electron micrographs of phage lysates have long been cited as support for the organization of DNA in a spool-like fashion. This particular model, like all other models, has not been found to be consistent will all available data. Recently we proposed that DNA within toroidal condensates produced in vitro is organized in a manner significantly different from that suggested by the spool model. This new toroid model has allowed the development of an alternative model for DNA organization within bacteriophage heads that is consistent with a wide range of biophysical data. Here we propose that bacteriophage DNA is packaged in a toroid that is folded into a highly compact structure.     

Relocation of Croton sonderianus (Euphorbiaceae) seeds by Pheidole fallax Mayr (Formicidae): a case of post-dispersal seed protection by ants?

Although seed dispersal by ants might reduce seed predation near the parent plants, predation on discarded seeds clustered on nest refuse piles may reduce any initial benefit provided by seed removal. Here we examine the fate of Croton sonderianus seeds that were discarded by Pheidole fallax Mayr ants on their nest refuses in caatinga vegetation of northeast Brazil. We collected all seeds discarded in refuse piles of 20 nests and within a radius of 50 cm from their borders, and examined them for evidence of predation. A total of 3,017 seeds were recorded either located in the P. fallax refuse piles (89.1%) or nest vicinity (10.9%). Predation was three fold higher in nest vicinity as compared to refuse piles. By removing seeds from beneath parent plants and relocating then to refuse piles, P. fallax is possibly providing double protection services for C. sonderianus seeds. Our findings represent the first evidence for predator-avoidance as benefit for plants resulting from ant seed-dispersal in the neotropics.     

Refuse Production in Leaf-cutting Ants (Hymenoptera: Formicidae) and its Relationship with Leaf Harvest

We examined the relationship between fungal refuse production and vegetation input in a laboratory colony of the leaf-cutting ant Acromyrmex coronatus. We found only a strong 6-day time-delay in the production of refuse with variation in substrate intake.     

Refuse Production in Leaf-cutting Ants (Hymenoptera: Formicidae) and its Relationship with Leaf Harvest

We examined the relationship between fungal refuse production and vegetation input in a laboratory colony of the leaf-cutting ant Acromyrmex coronatus . We found only a strong 6-day time-delay in the production of refuse with variation in substrate intake.     

The preoptic area of the domestic fowl

Summary The preoptic area of the domestic fowl (Gallus gallus) was studied by means of the Golgi technique. At least two regions can be recognized: (i) a medial and (ii) a lateral area, clearly distinguishable laterally from the adjacent telencephalic regions. The dendritic organization of the preoptic area is quite uniform. The neurons can be classified as isodendritic elements. The magnocellular elements are few and irregularly scattered mostly in the periventricular grey of the medial preoptic area. Of relevant interest is also the observation of some bipolar and horizontal neurons in the dorsal part of the medial preoptic area, near the anterior commissure.     

Effects of in situ nitrogen removal on degradation/stabilization of MSW in bioreactor landfill

The effects of in situ nitrogen removal on degradation of municipal solid waste (MSW) in bioreactor landfill system were investigated. The in situ nitrogen removal bioreactor landfill (NBL) consisted of fresh-refuse filled, methanogenic and nitrifying reactors was operated. The two-phase bioreactor landfill (BL) comprised of fresh-refuse filled and methanogenic reactors was used as control. The methanogenic and nitrifying reactors were all loaded with aged refuse whose placement time was 6-7 yr. Furthermore, the nitrifying reactor was in situ aerated. The results showed that the degradation of fresh-refuse was delayed and CH4 production also was reduced in the in situ nitrogen removal bioreactor landfill. It was feasible to perform in situ ammonia nitrification in aged refuse. Moreover, the efficiency of oxygen utility was high during the in situ nitrification because of the porous characteristic of aged refuse. Supplementing only 8.5mg O2 mg(-1)Nd(-1) to aged refuse could make ammonia removed completely. However, aeration did not accelerate the further stabilization of aged refuse.     

Archaeobotanical remains found in a house at the archaeological site of Cardonal,valle del Cajón,Argentina: a view of food practices 1,800 years ago

This paper explores food and daily activities in domestic areas at the archaeological site of Cardonal, Provincia de Catamarca, Argentina. It is based on archaeobotanical carpological macro remains recovered by flotation techniques in a residential compound. A set of five taxa including wild plants such as Geoffroea decorticans (chañar), Phaseolus vulgaris var. aborigineus (wild bean), Prosopis sp. (algarrobo) and the crops P. vulgaris var. vulgaris (domesticated bean) and Zea mays (maize) were identified. These well-known staples of ancient communities in this area suggest that the Cardonal people combined agriculture with foraging practices, taking advantage of a diversified environment and extensive social networks. The most abundant plant food remains were bean cotyledons and maize cupules, which were densely concentrated in the “kitchen”, near the hearth. Conversely, chañar endocarps, algarrobo seeds and also Chenopodium sp. seeds were almost exclusively confined to the “patio”, in the hearth area. As a result, two distinct food-related activity areas could be identified, defined by the relative density of plant remains, occurrence of plant taxa and the different practices of processing and consumption which they evoke.     

Effects of an open refuse pit on space use patterns of spotted hyenas

Although the use of anthropogenic food sources by carnivores is well documented, few studies have investigated the potential for these sites to influence the movements of livestock predators. We capitalized on a natural experiment in which a refuse pit, utilized by a group of intensively monitored spotted hyenas ( Crocuta crocuta ) in the Masai Mara National Reserve, Kenya, was closed midway through monitoring efforts. We compared hyena space use patterns before and after closure, while controlling for other variables, to investigate the influence of the pit on home range size, core area size and location, and the proximity of hyenas to dens and the refuse pit itself. We also investigated the influence of prey abundance and the social ranks of individual hyenas on variation in frequency of pit utilization. We found home range size to increase and core area size to decrease following pit closure. Space use was clearly influenced by the pit, as the group core area included the refuse site only while it was in operation, and hyenas were found closer to the pit before than after its closure. The most common rank group observed feeding at the pit were low-ranking females, and regular pit users were more likely to be found near the pit during times of relative prey scarcity. We discuss the potential of human refuse at pastoral villages to increase livestock losses to hyenas.     

Nutrient transfer supports a beneficial relationship between the canopy ant,Azteca trigona,and its host tree

1. Energy fluxes between ants and plants have been a focal point for documenting mutualistic behaviour. Plants can provide resources to ants through the production of extrafloral nectaries. In exchange, ants can fertilise plants through their nutrient‐ and microbe‐rich refuse. 2. Here, we test a potential facultative mutualism between the carton‐nesting canopy ant, Azteca trigona, and their host trees. Through observational and experimental approaches, this study documents how nutrient transfer provides a basis for this beneficial ant–plant relationship. 3. In a greenhouse experiment, fertilisation with sterilised refuse (i.e. nutrients only) increased seedling growth three‐fold, while the refuse with its natural microbial community increased growth 11‐fold. 4. Total root density was doubled in refuse piles compared with the surrounding area in situ. On average, refuse provides host trees and the surrounding plant community with access to a > 800% increase in N, P and K relative to leaf litter. 5. Azteca trigona preferentially nests in trees with extrafloral nectaries and on large, longer‐lived tree species. 6. Given the nutrient‐poor nature of the Neotropics, host trees probably experience significant benefits from refuse fertilisation. Conversely, A. trigona benefit from long‐term stable structural support for nests and access to nutrient‐rich extrafloral nectaries. Without clear costs to either A. trigona or host trees, it is proposed that these positive interactions are preliminary evidence of a facultative mutualism.