Who’s what? Prompt recognition of social status in crayfish

Crayfish are excellent model organisms to study the proximate mechanisms underlying the maintenance of dominance hierarchies in invertebrates. Our aim here was to investigate whether Procambarus clarkii males use social eavesdropping to discriminate dominant from subordinate crayfish. To this end, we conducted an experiment composed of a “passive” and an “active” phase. In the passive phase, “focal” individuals were allowed (treatment 1) or not (treatment 2) to see and smell two size-matched crayfish fighting while, in the subsequent active phase, they were allowed to freely interact with the fighting dyad. None of the recorded variables showed any significant difference between the two treatments, but, invariably, focal individuals were able to promptly discriminate dominant from subordinate crayfish. This study provides evidence that male crayfish recognize the social status of a conspecific without the need of direct or indirect experience with it and avoid dominants—and thus dangerous opponents—by means of a badge of status. A form of “winner and loser effects” could also contribute to the structuring of dominance/subordinate relationships. The implication of these results in understanding the maintenance of dominance hierarchies in invertebrates are discussed and compared with findings previously achieved in the context of mate choice by P. clarkii females, who do appear to use eavesdropping to identify dominants and subordinates.     

Whirligig beetle aggregations: what are the costs and the benefits?

Laboratory experiments investigated the benefits and costs of aggregation formation in the whirligig beetles, Gyrinus marinus and G. substriatus (Coleoptera: Gyrinidae). Different sized groups of whirligigs were exposed to fish predators, and capture rate per group and per individual were estimated. Attack rate per group increased with group size, suggesting that these aggregations behave as selfish herds. In another series of experiments in which whirligigs were exposed to top- and side-attacking predators, large groups were found to detect predators when they were further away than small groups. Video analysis of these groups showed that beetles tended to increase their swimming speed after exposure to a predator but did not show an increased tendency to circle. In natural aggregations, filmed in the field, swimming speed was found to be related to group size. Body condition of field collected beetles, as estimated from the regression of body mass on body length, was not found to be related to group size, implying that large groups do not suffer reduced condition. Received: 31 January 1997 / Accepted after revision: 24 November 1997     

Saharan dust clouds and human health in the English-speaking Caribbean: what we know and don’t know

Dust clouds travel across the Atlantic to the Americas and the Caribbean Islands. This long-range transport of dust leads to clouds that are enriched with small particles less than 10 microm aerodynamic diameter (PM10) which can reach human airways. The dust clouds also bring pollen, microbes, insects and chemicals, all of which could potentially have a negative impact on human health. This has led to a small number of retrospective studies being conducted on the islands of Barbados and Trinidad to look at possible associations between dust cover and acute asthma admissions to Emergency Rooms. The results have been conflicting. This review examines these studies, offers possible explanations for the differences in results, and suggests that there is a need for a prospective Caribbean-wide study to assess fully any relationship between African dust clouds and human respiratory and cardiovascular diseases.     

Sustainable livelihoods and people’s vulnerability in the face of coastal hazards

The present study investigates into the link between people’s vulnerability in the face of coastal hazards and sustainable livelihoods. It focuses on the town of Borongan in the Philippines and draws on questionnaire-based surveys and focus group discussions. This research shows that local fishermen are often compelled to go out fishing despite pending typhoon or storm surge to sustain the daily needs of their family. Its also demonstrates that the capacity of these people to protect themselves from the threat is constrained by poor and fragile livelihoods. In the event of a crisis, the study argues that people resort to a range of adjustments on their daily life which is rooted in the strength and diversity of their livelihoods. To reduce people’s vulnerability and enhance capacities to face coastal hazards, the study fosters Community-Based Disaster Risk Reduction with special emphasis to sustainable livelihoods.     

Where is the western limit of the tropical Indian Ocean seaweed flora? An analysis of intertidal seaweed biogeography on the east coast of South Africa

New, large-scale collections have been made of marine benthic macroalgae (seaweeds) on the east coast of South Africa, and the distributions of shallow-water species were analyzed in detail by multivariate, clustering and -diversity methods. The two northernmost sites are distinct, with a predominance of tropical species, and it is concluded that the changeover from a tropical Indian Ocean flora to a temperate South African flora occurs most rapidly in the vicinity of St. Lucia, 135 km south of the Mozambique border. It is imperative that all future biogeographical studies on the South African inshore marine biota include detailed collections north of St. Lucia. The remaining 440 km of the South African east coast (southern and central Kwazulu-Natal Province) is populated by a mixture of tropical and temperate elements, with only 2% endemism in this data set. This, thus, represents a true overlap region, with relatively equal numbers of species with affinities in the temperate Agulhas and tropical Indo–West Pacific floras, rather than a distinctive sub-tropical marine province, as the South African east coast is considered to be by most previous authors. The distinction between this overlap region and the south coast (Agulhas) region proper is not as clearly distinct. The change from a temperate to a tropical flora shows a relative increase in green algae from 15% to 25% of the species present. Criteria for the delineation of marine biogeographical regions are critically discussed, and it is concluded that the monitoring of distributions of all species, including rare species, is necessary. This is particularly relevant with regard to using these data to assess effects of potential changes in seawater temperature, including those which may be caused by global warming. Criteria for the delimitation of biogeographic entities such as "marine provinces" need to be clearly spelt out in all investigations.Communicated by O. Kinne, Oldendorf/Luhe     

Competition and group size in Thomas’s langurs (Presbytis thomasi): the folivore paradox revisited

Among primates, group size is highly variable. The standard ecological model assumes that better predation avoidance as group size increases favours living in larger groups, whereas increased travel costs and reduced net food intake due to within-group competition for resources set the upper limit. Folivorous primates, however, tend to defy this generalisation in that some live in small groups despite low costs of feeding competition. To resolve this ’folivore paradox’, it has been suggested that folivore group size is limited by social factors such as male harassment or infanticide, or that females can disperse more easily and thus maintain group size near optimum levels. In this paper, we examine the effects of group size on home range size, day-journey length, activity budget and diet in wild Thomas’s langurs (Presbytis thomasi), which live in one-male multi-female groups with a limited life cycle. We examined only data from the stable middle tenure phase when factors such as the strength of the breeding male or the way in which groups were formed did not influence ranging and activities. During this phase, group size affected day-journey length and home range size, and had a minor effect on diet, but did not influence time spent feeding or resting, allogrooming or birth rates. Hence the upper limit to group size during the middle tenure phase in Thomas’s langurs is not set by feeding competition. The folivore paradox is not due to frequent female dispersal in Thomas’s langurs. The timing of female dispersal is not as expected if it serves to keep group sizes near the ecological optimum, and groups seem to be below this optimum. Instead, female reproductive success is presumably maximised in small to mid-sized groups because larger groups show a clear trend to experience higher risk of take-over, often accompanied by infanticide. Because females can redistribute themselves among nearby groups when groups reorganise each time a new male starts up a new group, females can keep the group small. Thus, a social factor, risk of infanticide, seems to provide the selective advantage to small group size in Thomas’s langurs. Received: 29 July 1999 / Revised: 17 November 1999 / Accepted: 15 October 2000     

Chao’s lower bound estimator and the size of the Pleiades

Environmental and Ecological Statistics - In this note we would like to point out that the lower bound estimator of the frequency of hidden units in a target population, developed by Chao in...     

Worker self-restraint and policing maintain the queen’s reproductive monopoly in a pseudomyrmecine ant

Division of reproductive labor in insect societies is often based on worker self-restraint and both queen and worker policing. Workers of many hitherto studied wasps, bees and ants do not lay eggs in the presence of a queen. However, it is presently unclear how far these observations in a few select clades can be generalized. We investigated if and how queens maintain a reproductive monopoly in colonies of the elongate twig ant, Pseudomyrmex gracilis, a member of the previously unstudied ant subfamily Pseudomyrmecinae. Colonies are usually headed by a single, singly mated queen (monogyny, monandry). Workers therefore would be more closely related to males produced by other workers (r?=?0.375) than to the sons of queens (r?=?0.25). Nevertheless, workers appear to refrain from laying male-destined eggs in the presence of the queen. In queenless conditions, workers form dominance hierarchies by antennal boxing, and only one or a few high-ranking individuals readily begin to lay eggs. When returned into a queenright colony, egg-laying workers are immediately bitten, stung and expelled or killed by other workers. While the composition of cuticular hydrocarbons clearly differed between castes, it less clearly reflected worker ovarian development. An association with worker ovarian development that would allow workers to monitor the reproductive status of nestmates could only be tentatively postulated for certain substances. Our study broadens our knowledge about reproductive conflict in social Hymenoptera and shows that worker sterility in the presence of a queen is more common in monogynous, monandrous ants than expected from relatedness alone.     

An analysis of the developmental differences in Borneo’s Southeastern and Northwestern Coastal Zones

In this research, Landsat TM images were used to extract the land use information for Borneo’s coastal zones (0 to 35 km) during three time periods (1990, 2000, and 2010). Then, in combination with the DEM and shoreline types, the developmental differences under the influences of the geographical boundaries of the Borneo coastal zones were examined from such perspectives as the spatial distribution characteristics of the land development, sea-land gradient variation characteristics, and comparative analyses of the different regions. The results indicated that the geographic boundaries, as well as the different countries, had great influences on the development of the coastal zones. The regions with the most active development in Borneo’s coastal zones were mainly located in the estuary bay, onshore with land on both sides, and the near-shore alluvial plain with DEM?<?50 m. The northwestern coast zone showed relatively flat topography, and was close to an important international waterway. Therefore, the development in this area was found to be more intense than in the southeastern coastal zone, and which was characterized by a long developmental history. On one side of the geographical boundary, the development was also found to differ among the different countries. Malaysia was observed to be dominated by industrial plantations. Meanwhile, the industrial plantations, agriculture, and aquaculture in Indonesia were significantly increased, which was closely linked with the national economic policies. Furthermore, the development of Borneo’s coastal zones has led to vegetation degradation towards a constant inland development, plantation enlargements, agricultural development, and cleared and burnt areas, which have resulted in the land use transfer of 22,000 km² of forest land within the 0 to 35 km range.     

REDD+ and forest tenure security: concerns in Nepal’s community forestry

As one of the dominant large-scale mechanisms proposed to combat climate change, biodiversity loss, and rural poverty, REDD+ (Reducing Emissions from Deforestation and Forest Degradation) has added further complexity to the challenging governance of rights and resources in global forests. As REDD+ is commodifying carbon, concerns emerge about how carbon ownership and its rights can be accommodated into the existing framework that governs local forest resource rights. The Nepalese government has formally entered into REDD+ policy preparations, but it lacks clear legal provisions regarding key forest tenure rights such as carbon ownership, benefit sharing, and the political participation of community forest user groups from national to local. As a result, Nepal’s policy process points toward performance-based carbon forestry in a way that may undermine and weaken existing community tenure rights and forest tenure security.

This paper discusses Nepal’s potential impacts of new REDD+ and carbon ownership arrangements on forest tenure security and community-based forest governance. In a threefold methodological approach, the paper presents three scenarios for a REDD+-oriented tenure reform within the existing framework and assesses their concerns through in-depth qualitative interviews with key stakeholders, representatives, and advocates of Nepal’s community forestry system, complemented by a review of government documents and academic literature of REDD+ lessons so far. The analysis identifies critical concerns for forest tenure security, state-community power relationships, and effective local institutions of the commons, and suggests that Nepal’s REDD+ process is taking place at a particularly consequential time for structural changes of the forest governance framework.     

Dalliances and doubtful dads: what determines extra-pair paternity in socially monogamous wandering albatrosses?

Genetic techniques have revealed surprisingly high rates of extra-pair paternity (EPP) in socially monogamous albatrosses. We sought to establish social and genetic influences on EPP in wandering albatrosses (Diomedea exulans) at Marion Island, where EPP rates were 14–24?% in three successive seasons. EPP probably resulted from both female solicited extra-pair behaviours and male forced copulations. EPP was not linked to breeding experience nor with poor reproductive performance, despite a tendency for pairs to consistently produce either EPP or within-pair paternity (WPP) chicks. Mate guarding may inhibit extra-pair behaviour; however, parental arrival date and presence in the colony prior to laying did not correlate with EPP. There was little support for genetic advantages to producing EPP chicks, but the population is characterised by low genetic variability, which may result in mate incompatibility. Mates of pairs that failed and pairs producing EPP young tended to be more similar genetically to their partners than mates producing WPP young, suggesting that EPP may counter mate incompatibility. EPP and WPP chicks grow equally well, so cuckolded males did not reduce investment in EPP chicks. The lack of discriminatory behaviour by cuckolded males together with low genetic diversity in the population may allow continued high levels of EPP. In albatrosses, pair bonds are typically long lasting and the costs of forming new pairings may discourage mate swapping. Females may undertake extra-pair copulations as an adaptive alternative to mate swapping because the costs of extra-pair behaviour are small.     

After the flames then what? exploring the linkages between wildfires and household food security in the northern Savannah of Ghana

ABSTRACT

This study deploys the livelihoods theory in political ecology together with integrated methods including remote sensing, participatory geographic information systems, interviews and focus group discussions to explore the intricate and dynamic linkages between perennial wildfires and household food insecurity among smallholder farmers in the northern savannah zone of Ghana. Our results suggest that wildfires are a major pathway to household food insecurity in two ways, as perceived by the farmers. First, in instances where wildfires destroy the major crops of smallholders, they are unable to find enough food for the lean season which results in transitory food insecurity. Secondly, in the long term, the environmental impacts of wildfires on the soil lead to lower yields and inadequate food to meet household nutritional needs. Farmers then deploy certain strategies such as early-harvesting and switching to early-maturing crops to avoid with the perennial fires and these strategies further reinforce other dimensions of food insecurity such as nutrition insecurity. Because livelihoods strategies such as crop farming, hunting, charcoal production and herding intersect in the northern savannah zone, we recommend policy options that will engage community members in finding common ways of using shared spaces sustainably. Government should also adopt policies that will encourage domestication of certain livelihood strategies such as cattle herding.     

On the shoals of giants: natural catastrophes and the overall destruction of the Caribbean’s archaeological record

In this paper I review a host of natural and cultural processes that have affected the preservation and integrity of archaeological sites on islands in the West Indies, many of which are located in low-lying coastal areas. Given the position of the Caribbean lithospheric plate—juxtaposed between four others—it is no surprise that by its very nature the region is volcanically active and frequently associated with earthquake and tsunami events. This makes coastal zones, and related archaeological sites in the region, highly susceptible to a wide range of destructive natural events. The high frequency of tropical systems (hurricanes and storms) in the Caribbean and rising sea level, coupled with human activities such as sand mining, development, and looting, makes the region’s archaeological record one of the most vulnerable and threatened in the world. Ongoing research is dedicated to understanding how past populations may have been affected by these events in the past.     

PAHs in indoor dust samples in Shanghai’s universities: levels, sources and human exposure

Given the significant amount of time people spend indoors, the occurrence of polycyclic aromatic hydrocarbons (PAHs) in indoor dust and their potential risks are of great concern. In the present study, ten dust samples from lecture theatres and twelve samples from dining halls were collected from university campuses in Shanghai to investigate the PAH levels, possible sources and human exposure. The total concentrations of 18 PAHs ranged from 9.84 to 21.44?μg/g for dust samples from lecture theatres, and 9.63-44.13?μg/g for samples from dining halls. Total PAH concentrations in indoor dust samples showed a better correlation to black carbon compared to total organic carbon contents. PAHs in dining halls samples showed a similar distribution pattern with that of commercial kitchen air, which indicated that cooking activities could contribute most of the PAHs found in dining halls. Principal component analysis revealed both petrogenic and pyrogenic sources. The potential health risk for PAHs was assessed in terms of BaP equivalent carcinogenic power and estimated daily intake (EDI). Relatively high EDI values compared to other studies suggested that PAHs posed a potential threat to human health in indoor environments at Shanghai's universities.     

‘Development’ at the crossroads: biodiversity and land-use tensions on South Africa’s Wild Coast

In South Africa, extreme rural poverty often geographically overlaps with areas of high and important biodiversity. Attempts to bring about land-based poverty reduction projects in such areas tends to trigger tensions among stakeholders purporting to be concerned about local people’s welfare, as well as the environment. Using discursive document analysis and semi-structured interviews, the paper discusses a case study of the Wild Coast, an area celebrated for its high biodiversity and ‘beauty’, which reveals that a tension among environmental non-government organisations, government agencies and the private sector, on the best development option, exacerbates the threats to local livelihood options and biodiversity conservation.     

Mapping and evaluating sugarcane expansion in Brazil’s savanna using MODIS and intensity analysis: a case-study from the state of Tocantins

In Brazil, the main biofuel crop is sugarcane, and with its rapid expansion, there is much debate about what land uses and land covers it is replacing, and what are the associated environmental and social impacts. Some argue sugarcane is mainly replacing cattle pasture, thus having minimal impacts on native vegetation and small-scale family farming. In contrast, others claim sugarcane is replacing cropland traditionally under soybeans, rice, beans, and corn. Thus, food security is negatively affected and small-scale family farming livelihoods and culture are threatened. This is a proof-of-concept paper illustrating methods contributing toward the resolution of such debates. First we map land use and cover change in areas undergoing sugarcane expansion using satellite data from MODIS (Moderate Resolution Imaging Spectroradiometer); second, we test the hypothesis that sugarcane is replacing traditional annual crops using intensity analysis, via a case study of land change in the municipality of Pedro Afonso, Tocantins in northern Brazil between the 2008–2013 crop years. Maps matched reference data with overall agreements between 87–91%. Intensity analysis confirmed sugarcane is replacing annual crops much more than cattle pasture and other land uses and covers, pointing to particular economic and social processes driving land change.     

Regional-scale variation in the distribution and abundance of farming damselfishes on Australia’s Great Barrier Reef

Territorial damselfishes that manipulate (“farm”) the algae in their territories can have a marked effect on benthic community structure and may influence coral recovery following disturbances. Despite the numerical dominance of farming species on many reefs, the importance of their grazing activities is often overlooked, with most studies only examining their roles over restricted spatial and temporal scales. We used the results of field surveys covering 9.5° of latitude of the Great Barrier Reef to describe the distribution, abundance and temporal dynamics of farmer communities. Redundancy analysis revealed unique subregional assemblages of farming species that were shaped by the combined effects of shelf position and, to a lesser extent, by latitude. These spatial patterns were largely stable through time, except when major disturbances altered the benthic community. Such disturbances affected the functional guilds of farmers in different ways. Since different guilds of farmers modify benthic community structure and affect survival of juvenile corals in different ways, these results have important implications for coral recovery following disturbances.