The rocky intertidal zone of sheltered shores in Breiðafjörður, north-west Iceland is dominated by monospecific stands of canopy-forming brown algae Ascophyllum nodosum, which provide habitat for mobile organisms and has been subjected to long-standing rotational harvesting. We investigated the assemblage composition of little-studied mobile brachyuran crabs in this area, to track distributional shifts in a native species responding to climate change and extent of occupancy of the intertidal by a primarily subtidal invasive non-native species. Potential interactive effects of seaweed harvesting were explored. Breiðafjörður was compared with two reference sites in Faxaflói, south-west Iceland. The study revealed clear poleward expansion of the native European green crab Carcinus maenas in the region, displacing the native spider crab Hyas araneus particularly at mid-shore levels. The invasive non-native Atlantic rock crab Cancer irroratus had negligible occupancy in the intertidal zone, indicating limited effects on the intertidal crab assemblage, composition, and abundance. The current harvesting regime of A. nodosum in Breiðafjörður did not affect the composition and abundance of the brachyuran crab assemblage in the rocky intertidal zone. H. araneus is likely being squeezed by displacement subtidally by C. irroratus, and intertidally by C. maenas. Overall, we provide insights into the potential interactions between climate change, invasive species, and human activities in the rocky intertidal zone.

How hunter-gatherers manipulated and utilised their natural surroundings is a widely studied topic among anthropologists and archaeologists alike. This focuses on the Natufian culture of the Late Epipalaeolithic period (c. 15–11.7 kyr), the last Levantine hunter-gatherer population, and specifically on the earliest composite tools designed for harvesting. These tools are widely referred to as sickles. They consisted of a haft into which a groove was cut and flint inserts affixed. This revolutionised harvesting and established it on new grounds. While the plants manipulated by these tools are yet to be identified with certainty, it is evident that these implements were rapidly integrated and dispersed throughout the Natufian interaction sphere, suggesting that they provided a significant advantage, which probably constituted a critical step toward agriculture. At the same time, the Natufian haft assemblage demonstrates high morphometric variability. We review the available data concerning Natufian hafts and offer three possible models to explain the noted variability. We conclude that while these models are not mutually exclusive, this varied technological pattern is best understood as deriving from a protracted formative phase of technological development, progressing through incremental processes of trial and error.

Flowering rush (Butomus umbellatus L.) is an invasive aquatic and wetland plant capable of developing monotypic stands in emergent and submersed sites. This plant can rapidly outcompete native vegetation and impede human practices by reducing recreation (boating, fishing, and skiing) and disrupting agricultural use of water resources (irrigation canals). Mechanical removal practices occurring biweekly, monthly, bimonthly, and once per growing season were compared with chemical control with diquat applied sequentially at 0.19 ppmv ai for two consecutive months over 2 yr (2016 and 2017). Biweekly removal gave the most consistent control of B. umbellatus biomass and propagules. Diquat application along with monthly and bimonthly clippings gave varying degrees of B. umbellatus control. Clipping once per growing season did not control B. umbellatus when compared with reference plants, while clipping B. umbellatus every 2 wk (biweekly) controlled rush propagules most effectively. However, it is unlikely this method will be sufficient as a stand-alone control option due to the slow speed of harvester boats, the potential these boats have to spread B. umbellatus propagules to more sites, and the expense of mechanical operations. However, clipping could be used as part of an integrated strategy for B. umbellatus control.

A modified predator-prey system described by two differential equations and an algebraic equation is discussed. Formulae for determining the direction of a Hopf bifurcation and the stability of the bifurcating periodic solutions are derived differential-algebraic system theory, bifurcation theory and centre manifold theory. Numerical simulations illustrate the results, which includes quite complex dynamical behaviour.

Molluscs are subjected to intense harvesting in many areas around the world. Conservation measures have been developed to preserve populations of an overexploited gastropod species, the abalone Haliotis tuberculata coccinea. This species was surveyed in subtidal localities throughout coastal Tenerife, Canary Islands over the last two decades (1994–2014). A clear indicator of non-recovery was observed in the decrease of mean size throughout the last two decades, even after the inclusion of this species in the Regional Catalogue of Endangered Species. The mean size of abalones decreased from 33.5 mm (1994) to 28–29 mm (2002 and 2014), corresponding to sub-adult individuals. The structure of size classes was typical of an overexploited species, with reduced occurrence of large individuals (>50 mm). Several factors might explain this pattern such as illegal harvesting, proliferation of featureless benthos and a decrease of suitable habitats for colonization and settlement. Complementary conservation actions are urgently needed to preserve this species in the area studied.

In this paper, some theoretical aspects and experimental results are discussed with the aim to provide supplementary dc energy to radio frequency identification (RFID) tags by exploiting the nonlinear nature of rectifier devices. Three nonlinear phenomena are treated: (i) the impedance power dependence, (ii) the harmonic production, and (iii) the dependence on the radio frequency waveform. The novelty of the work relies on proposing a double rectifier composite system in where the nonlinearity of each rectifier is exploited to enhance the global powering performance of the system. Using the passive RFID technology as a beacon for the implementation, the approach considers combining the internal rectifier circuit of a commercial RFID chip operating at 868 MHz with an external rectifier circuit operating at 2.17 GHz. The solution triggers in a composite system RFID tag-harvester integrated in a single-feed dual-band antenna. The experimental validation shows 5 dB of tag sensitivity enhancement when it is empowered by the external harvester. The enhanced sensitivity produces an increase in the theoretical reading range distance from 3.3 to 6.1 m.

This paper discusses novel methodologies for the characterization of harmonic signals generated by wireless powered devices, i.e. passive ultra-high frequency (UHF) radio frequency identification (RFID) tags, due to the wireless power transferred from reader to tag. Theoretical aspects, as well as measurements to characterize these non-linear phenomena are exposed. Particular care is taken to explain the analysis methodology and setup for two kinds of characterization measurements: radiated and conducted. The existence of harmonic signals carrying information is exploited in an advanced application example. A dual-band RFID tag is designed to increase the backscattered harmonic level in the tag-to-reader link. Measurement of this dual band tag demonstrates the exploitation of the hitherto neglected harmonic power; it also opens the door to more advanced applications exploiting the harmonic-link communication.

European agricultural landscapes hold important endangered and game species, which may add socioeconomical and ecological value to the ecosystem, and thus must be considered priority species in any management programme integrating agriculture, hunting and conservation. Patterns of red-legged partridges (Alectoris rufa) nesting habitat selection and nesting success provide information for the implementation of these kinds of programmes in agrarian pseudosteppes. Nests occur mainly in cereal grain fields, although this habitat type was overall negatively selected and had the lowest nesting success. Only lindes (herbaceous strips among fields) were positively selected, and were also the habitat type with the highest nesting success. Nests within cereal grain fields were positively selected close to the field margins (mostly < 5 m). Agricultural practices, particularly harvesting, were the main cause of nest failure. Changes in agricultural practices would be a more effective means of increasing nesting success than predator control. Partridge breeding success may be improved by better management of agricultural areas, increasing the availability of lindes and slightly delaying cereal harvesting. These data may have implications for other endangered steppe-birds with similar nesting habitat, and may provide the basis for effective and successful collaborative programmes between hunters and conservationists.

In this paper we review evidence for, and anticipated consequences of, climate change in Antarctic marine communities, examining the potential impacts on invertebrates and vertebrates alike and exploring plausible outcomes for species, with examples principally from the Antarctic literature. We suggest that industries with the greatest potential to aggravate climate change impacts on marine communities are marine capture fisheries. In the Southern Ocean, harvesting is governed under the Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR). CCAMLR espouses an ecological management framework and so has the capacity to mitigate harvesting impacts such that they do not worsen impacts from climate change. We discuss some of the implications of climate change and advocate that CCAMLR address certain key issues if it is to fulfil its international obligations. It will be essential for CCAMLR to determine relative risks (uncertainties), impacts and timescales, of various processes consequent on climate change. Such risk assessments should be feasible with current knowledge and should provide a focus for future work. We believe it will be important to prioritize issues that reduce impacts and uncertainties by the greatest degree, and propose that future plans should involve shared responsibility (e.g. with SCAR etc.) for each of the risks described.

Introduction. Pomegranate (Punica granatum L.) is the main and most valuable fruit crop of the northern mountainous region of Oman. Pomegranates are cultivated utilizing traditional farming methods including the determination of harvest dates, harvesting and postharvest handling. Materials and methods. Fruit of four native pomegranate cultivars [‘Hamedh’, ‘Malasi’, ‘Helow’ and ‘Qusum’, literally translated as sour, smooth, sweet and hard-seeded, respectively] were tagged and monitored for 3 months up to commercial harvest. Fruit length (L) and diameter (D) were measured at weekly intervals starting from 66 d after full bloom until harvest (136 d after full bloom). Results and discussion. During the time course of fruit growth and development, significant changes occurred in fruit shape assessed by the [fruit length / fruit diameter] ratio in two cultivars (‘Malasi’ and ‘Hamedh’), but not in the ‘Helow’ and ‘Qusum’ cultivars, which also had larger fruit size at harvest. The lack of obvious changes in fruit shape during growth and development of ‘Qusum’ and ‘Helow’ pomegranate cultivars indicates that the attainment of characteristic fruit shape may not be a good indicator of their maturity for harvest management. Thus, fruit harvesting based solely on size and shape is not sufficient and other physico-chemical fruit attributes should be taken into account when assessing readiness to harvest to ensure optimum income returns to growers.

In this survey, we briefly review some of our recent studies on predator-preymodels with discrete delay. We first study the distribution of zeros of a seconddegree transcendental polynomial. Then we apply the general results on thedistribution of zeros of the second degree transcendental polynomial to variouspredator-prey models with discrete delay, including Kolmogorov-typepredator-prey models, generalized Gause-type predator-prey models withharvesting, etc. Bogdanov-Takens bifurcations in delayed predator-prey modelswith nonmonotone functional response and in delayed predator-prey model withpredator harvesting are also introduced.

Introduction. The subjectivity of the external criteria used for the determination of mango maturity at its harvest led to the search for additional more reliable parameters to determine the optimal harvest maturity and able to replace the external and internal morphological indices. Materials and methods. Some physicochemical characteristics, such as colour of pulp, soluble dry extract, titratable acidity and weight loss, were evaluated on fruits of the cv. Kent (Mangifera indica L.) collected in North Cote d’Ivoire. The days necessary for ripening after harvest were estimated. Measurements were correlated to five maturity stages corresponding to the fruit harvest carried out at (76, 82, 88, 94 and 100) days after flowering. On each date of harvest, batches of 52 fruits were gathered. On half of them, maturation was observed as of harvest, the other half being kept at room temperature and the ripening evaluation then being done at the end of storage. Results. According to the harvest date, the soluble dry extract values varied from 8.3 °Brix to 10 °Brix at fruit harvest, and from 14.2 °Brix to 20 °Brix after ripening of the fruits stored at ambient temperature. Titratable acidity was correlated positively with maturity stage. Time to ripen and weight loss continuously decreased with the fruit maturity. For mangos of the cv. Kent, the date of the most suitable harvest seemed to be at 94 days after flowering. Mangos collected at 100 days after flowering developed better organoleptic characteristics such as sugar content, peel aspect and pulp colour than those of the fruit harvested earlier. Conclusion. Starting from the 94th day after flowering, the mango of the cv. Kent collected under the conditions of the North Cote d’Ivoire develops its best organoleptic characteristics during ripening.

Madagascar's endemic freshwater crayfish (Parastacidae: Astacoides) are harvested by local people for both subsistence use and small-scale trade. There has been concern that populations, and even species, are threatened by overexploitation but little is known about the harvest or its economic importance. We studied crayfish exploitation in eastern Madagascar over 3 years. The existence of local taboos (fady) preventing commercial crayfish harvesting, as well as access to markets and forest, influenced involvement in the harvest. All four crayfish species found in the region were harvested, but A. granulimanus provided the majority of the catch. In one harvesting village more than 50% of the 47 households were directly involved in the harvest, which contributed USD 2,382 to the village economy in 2003/2004, an important sum in the context of local incomes. Subsistence use was widespread, particularly by children to whom it may provide an important protein source. Community-based conservation (through transfer of harvesting rights and responsibilities for forest management to local communities) is central to a new conservation paradigm in Madagascar. This recognizes communities' long term interest in their natural resources and offers an ideal opportunity for those concerned with the sustainability of the harvest to implement management tools (such as avoiding reproductive females, size limits and no-take zones). We discuss each tool with respect to biological implications and practical constraints. We note that community-based approaches may not be sufficient to conserve rarer species, which make up a small proportion of the value of the harvest.

The overall design of Ca.U.M.Ha. (Cassino-Underactuated-Multifinger-Hand) for harvesting horticulture products is presented. Ca.U.M.Ha. shows an anthropomorphic design incorporating four underactuated finger mechanisms and a simplified contrasting thumb, which are all joined to a rigid palm. The pneumatic cylinders of the articulated fingers are operated in parallel in order to give an additional auto-adaptability on the object to grasp. An application of Ca.U.M.Ha. for grasping different shapes of apples is presented.

Introduction. La durée de vie verte (DVV), qui indique l’état physiologique des bananes à la récolte, est un critère de qualité majeur pour l’exportation des fruits. Afin d’évaluer et de comprendre la variabilité de la DVV existant en exploitation, une enquête diagnostic a été menée chez trois producteurs de bananes en Martinique utilisant la méthode des sommes thermiques comme outil de décision de récolte. Matériel et méthodes. Pour chaque producteur, des fruits ont été prélevés en sortie de station d’emballage sur 10 % des régimes récoltés pendant une semaine. Ces bananes ont ensuite été conservées à 14 °C dans des sacs perforés en polyéthylène jusqu’au stade de maturité « tournant vert ». La DVV a été définie par le temps écoulé en jour entre la récolte et ce stade de maturité. Résultats et discussion. La DVV a varié entre (18 et 69) jours avec une moyenne de 42 jours pour l’ensemble des producteurs. Près de 80 % de la production a eu une DVV entre (25 et 50) jours et moins de 4 % en dessous de 25 jours. La variabilité de la DVV a été liée principalement à l’âge des fruits à la récolte, exprimée en somme thermique (R = –0,74). Celle-ci a varié entre (600 et 1150) degrés-jour pour l’ensemble des exploitations. Les fruits contaminés par l’anthracnose de blessure et les pourritures de couronne ont présenté une DVV plus courte que les fruits sains et cela indépendamment du stade de récolte (p < 0,001). L’origine de cette contamination a été discutée. À même somme thermique, des différences significatives de DVV ont été mises en évidence selon le lieu de production (parcelle) (p < 0,001). Des écarts de plus de 7 jours en moyenne ont été observés entre des parcelles provenant du même producteur et situées à même altitude. L’origine de ces différences a également été discutée.

Fuelwood is still the primary energy source for rural households across the savannah biome of Africa. Coppice growth is an important species-specific trait that strongly influences fuelwood production and regeneration, and yet coppice growth patterns are poorly understood in African savannahs. It is therefore vital that factors affecting coppice growth of species, such as environment conditions and harvesting technique, be better understood in order to develop models for sustainable fuelwood use. This study investigated coppice growth and resource allocation strategies in relation to (1) position along the landscape catena and (2) harvesting technique, for three savannah fuelwood tree species: Dichrostachys cinerea, Albizia harveyi and Combretum collinum. The study was conducted in a dystrophic semi-arid savannah in the far north-east of South Africa. A total of 1146 harvested stumps were sampled in topland and bottomland sites in three locations around a rural village. Stump characteristics (diameter and height) and coppice shoot variables (number of shoots, length and diameter of each shoot, length of longest shoot, and diameter of fattest shoot) were measured for each stump. Three soil samples were taken in each site for physical and chemical analysis. No statistically significant differences were found in soil variables between topland and bottomland sites, probably due to low sample size. Coppice resource allocation strategies varied between species. D. cinerea exhibited a ‘quantity-driven’ strategy, with the production of large numbers of relatively small coppice shoots with high length:diameter ratio (shoot taper function). C. collinum exhibited a ‘quality-driven’ strategy, characterized by the production of a relatively low number of larger coppice shoots. Coppice growth variables for A. harveyi were intermediate between those of the other two species, suggesting a strategy where allocation of resources to the number and growth of shoots is more balanced. However, allocation of resources relative to the size of the cut stem, indexed by total shoot basal area:stump basal area ratio, did not differ significantly between species. Coppice growth was strongly favoured in bottomland sites for D. cinerea, and to a lesser degree, C. collinum. Catenal position had a negligible influence on coppice growth of A. harveyi. Number of shoots produced increased with cutting height for all three species. For all three species the number of shoots increased with stump diameter, and mean shoot size also increased with stump size for D. cinerea. There was a significant negative relationship between stump diameter and total shoot basal area:stump basal area ratio for A. harveyi and C. collinum. A framework for optimizing different coppice growth variables according to species, catenal position and harvesting technique is given.

We consider whether species richness in canopy gaps in coastal scarp forest (South Africa) is constrained by competition for a limited number of available niches or is a chance effect of recruitment and dispersal limitation on species derived from the surrounding species pool. In so doing we confirm findings from relatively species-poor New Zealand Nothofagus forest. We investigate the contrasting roles of determinism and chance, and the putative assembly of woody plants in gaps, using a technique in which the species richness of small, replicate local assemblages (0.25–m2 quadrats) are sampled within regions (the surrounding gap) that vary in total species richness. The form of the regression of local species richness against regional species richness indicates the extent to which community assembly is under local-ecological control (niche limited). Species richness of local assemblages was not niche limited and increased as a constant proportion of the size of the species pool in a gap. We argue that, in general, species assembly in these forest gaps is chance-driven, and discuss the management implications this has for selective pole-harvesting in these forests.