Conceptualizing and communicating management effects on forest water quality

We present a framework for evaluating and communicating effects of human activity on water quality in managed forests. The framework is based on the following processes: atmospheric deposition, weathering, accumulation, recirculation and flux. Impairments to water quality are characterized in terms of their extent, longevity and frequency. Impacts are communicated using a “traffic lights” metaphor for characterizing severity of water quality impairments arising from forestry and other anthropogenic pressures. The most serious impairments to water quality in managed boreal forests include (i) forestry activities causing excessive sediment mobilization and extirpation of aquatic species and (ii) other anthropogenic pressures caused by long-range transport of mercury and acidifying pollutants. The framework and tool presented here can help evaluate, summarize and communicate the most important issues in circumstances where land management and other anthropogenic pressures combine to impair water quality and may also assist in implementing the “polluter pays” principle.     

Fiddler crab burrowing affects growth and production of the white mangrove (<Emphasis Type="Italic">Laguncularia racemosa</Emphasis>) in a restored Florida coastal marsh

Positive plant–animal interactions are important in community ecology, but relatively little attention has been paid to their effect on the production of mangroves, dominant halophytic trees in tropical coastal marshes. Here, the role of fiddler crab (Uca spp.) burrowing on the growth and production of the white mangrove, Laguncularia racemosa (<2 years old), was examined in a restored marsh in Tampa Bay, Florida (27°41.65 N, 82°30.34 W) with manipulative experiments from June 2006 to May 2007. Fiddler crab burrowing significantly increased mangrove height by 27%, trunk diameter by 25%, and leaf production by 15%, compared to mangroves in crab exclusion enclosures. Additionally, the exclusion of fiddler crabs significantly increased interstitial water salinity from 32.4 to 44.2, and decreased the oxidation–reduction potential of the low organic sediments, but did not affect soil pH or sulfide concentration. Mangrove height, trunk diameter, and leaf production along a transect that varied in crab burrow density were positively associated with the number of crab burrows. Further, the density of sympatric Spartina alterniflora shoots was positively correlated with crab burrow density along the transect. As in temperate marshes, fiddler crabs can have significant ecological effects on mangrove communities, serving as ecological engineers by modulating the amount of resources available to marsh plants, and by altering the physical, chemical, and biological state of these soft sediment communities. In restored coastal systems that typically have very poor sediment quality, techniques such as soil amendment could be used to facilitate a more natural interaction between crabs and mangroves in ecosystem development.     

The reproductive ecology of the invasive ascidian, <Emphasis Type="Italic">Styela clava,</Emphasis> in Auckland Harbour,New Zealand

The ascidian Styela clava, native to the north-west Pacific, is an invasive species affecting New Zealand’s marine ecosystems, biodiversity and aquaculture operations. To provide detailed information on the reproductive biology of S. clava in New Zealand for post-border biosecurity management, long-term seasonal patterns of gametogenesis were determined from May 2006 to May 2008 in Auckland’s Waitemata Harbour (36°49′20″S, 174°45′85″E). Of particular interest was whether the critical 15°C threshold spawning temperature for reproduction observed in the Northern Hemisphere applied here to the first Southern Hemisphere study. S. clava gametogenesis followed a regular seasonal cycle with ripe gametes appearing as early as September and persisting to June; this time frame corresponds to the period when sea surface temperatures in the region first reach 15°C and with spawning occurring mainly during late summer to early autumn. From photoperiod manipulation, it was determined that spawning occurred at approximately 18:20. The extended reproductive period and a short generation time in the Waitemata Harbour provides a lengthy opportunity for S. clava to spread. Findings are discussed in relation to S. clava’s post-border management.     

The end of the fat dodo? A new mass estimate for <Emphasis Type="Italic">Raphus cucullatus</Emphasis>

A new mass estimate for the dodo (Raphus cucullatus), based on the lengths of the femur, tibiotarsus and tarsometatarsus, is attempted. The obtained mean mass is 10.2 kg, which is less than previous estimates based on other methods, which ranged from 10.6 to 21.1 kg, and much lower than the 50 lbs reported by a seventeenth-century eyewitness. The new estimated mass, which is similar to that of a large wild turkey, seems more realistic than previous ones and supports the hypothesis that contemporary illustrations of extremely fat dodos were either exaggerations, or based on overfed specimens. Pictures of “fat” dodos may also have been based on individuals exhibiting a display behaviour with puffed out feathers.     

Exploring the conservation status of an endangered coastal plant over the last nine years: a case study in Andalusia,Spain

Human pressure has been exponentially growing during recent decades in coastal areas, which have led to drastic losses of biodiversity in coastal ecosystems. The current conservation status of many coastal plant species is directly related to a lack of environmental criteria in the urban planning of coastal areas over recent decades. This study aimed to evaluate the evolution, over the last 9 years, of the conservation status of various populations of the endangered plant Glaucium flavum, exploring the extent to which human pressure and different management strategies practiced in the coastal areas where the populations are established have affected the conservation status of the species. The populations analysed have evolved in a different manner over the last 9 years, as have their threat factors, and a relationship was evident between their conservation status and the evolution of these different threat factors. Our results indicate that an appropriate planning of local management actions, such as the installation of walkways or the successful eradication of invasive species, may be determinant factors for successful conservation of the coastal vegetation. The presence of species that are sensitive to slight changes in the ecosystem, and the main factors that govern the plant performance of these species, must be given full consideration in decision-making processes of coastal planning and management.     

Male mating preference is associated with risk of pre-copulatory cannibalism in a socially polymorphic spider

We performed male attraction experiments and staged courtship sequences to test for non-random mating with respect to social behavioral phenotype in the comb-footed spider, Anelosimus studiosus. While asocial behavior is the dominant phenotype in all A. studiosus populations examined to date, a social phenotype approaches a frequency of 15% in colder environments. We collected test subjects from higher latitude polymorphic populations and scored all individuals as to their behavioral phenotype prior to their use in these trials. Males of both phenotypes differentially approached and courted social females over asocial females and no-spider controls. By offering males different numbers of females of one type vs. the other in subsequent trials, we determined that the difference in attractiveness between the two phenotypes social/asocial is 1.5/1. Both the web produced by a female and a female that has been removed from its web attract males. We suggest that the male attracting pheromone is present on females and is also attached to silk threads. Staged encounters completed between males and females of the respective phenotypes demonstrated that courting males suffer significantly less pre-copulatory sexual cannibalism with social females than with asocial ones, and thus, female social tendency is phenotypically linked to sexual aggression. We propose that the male preference for social females is adaptive because of the observed asymmetry in courtship success.     

Re-construction of the shut-down PM10 monitoring stations for the reliable assessment of PM10 in Berlin using fuzzy modelling and data transformation

A dense monitoring network is vital for the reliable assessment of PM10 in different parts of an urban area. In this study, a new idea is employed for the re-construction of the 20 shut-down PM10 monitoring stations of Berlin. It endeavours to find the non-linear relationship between the hourly PM10 concentration of both the still operating and the shut-down PM10 monitoring stations by using a fuzzy modelling technique, called modified active learning method (MALM). In addition, the simulations were performed by using not only raw PM10 databases but also log-transformed PM10 databases for skewness reduction. According to the results of hourly PM10 simulation (root mean square error about 13.0 μg/m³, correlation coefficient 0.88), the shut-down stations have been appropriately simulated and the idea of dense monitoring network development by the re-construction of the shut-down stations was realised. The results of simulations using raw and log-transformed databases showed that data transformation has no significant effect on the performance of MALM in the simulation of shut-down PM10 stations. By the combination of the 11 still operating stations and the 20 re-constructed stations, a dense monitoring network was generated for Berlin and was utilised for the calculation of the reliable monthly and mean annual PM10 concentration for five different PM10 zones in Berlin (the suburban-background, urban-background, urban-traffic, rural-background and suburban-traffic areas). The results showed that the mean annual concentration of PM10 at the five zones increased by about 13.0% in 2014 (26.3 μg/m³) in comparison with 2013 (23.3 μg/m³). Furthermore, the mean annual concentration of PM10 in the traffic lanes of the suburban (2013 25.0 μg/m³, 2014 26.9 μg/m³) and urban (2013 27.7 μg/m³, 2014 31.3 μg/m³) areas is about 14 and 20% higher than the PM10 concentration of suburban-background (2013 21.3 μg/m³, 2014 24.5 μg/m³) and urban-background (2013 23.0 μg/m³, 2014 26.1 μg/m³) areas, respectively.     

Size-dependent behavior of tuna in an array of fish aggregating devices (FADs)

Several lines of evidence indicate that aggregations of yellowfin tuna associated with floating objects are more frequently composed of small animals than larger ones. Also, the diet of small yellowfin tuna caught at anchored fish aggregating devices (FADs) around Oahu, Hawaii, was found to shift quite rapidly when these fish reached approximately 50 cm FL. In order to test for ontogenetic changes in aggregation behavior, we tagged and released two distinct size classes of yellowfin tuna in an array of anchored FADs around Oahu, Hawaii. Twenty-four yellowfin tuna 30–39 cm FL and 16 yellowfin tuna 63–83 cm FL were tagged with acoustic transmitters and released near anchored FADs equipped with automated acoustic receivers. Fish in the smaller size class stayed about 2.5 times longer at individual FADs than the larger fish (mean 4.05 days vs. 1.65 days) and displayed larger horizontal movements within the array. However, the durations of unassociated phases, residence times in the entire FAD array, percentage of time spent associated with FADs and numbers of movements between FADs did not show any difference between the two size groups. The observed size-dependent behavior is discussed in terms of physiological abilities, diet segregation and anti-predator behavior.     

Opportunities and challenges for mangrove carbon sequestration in the Mekong River Delta in Vietnam

Increasing value is attributed to mangroves due to their considerable capacity to sequester carbon, known as ‘blue carbon’. Assessments of opportunities and challenges associated with estimating the significance of carbon sequestered by mangroves need to consider a range of disciplinary perspectives, including the bio-physical science mangroves, social and economic issues of land use, local and international law, and the role of public and private finance. We undertook an interdisciplinary review based on available literature and fieldwork focused on parts of the Mekong River Delta (MRD). Preliminary estimates indicate mangrove biomass may be 70–150 t ha^?1, but considerably larger storage of carbon occurs in sediments beneath mangroves. These natural stores of carbon are compromised when mangroves are removed to accommodate anthropogenic activities. Mangroves are an important resource in the MRD that supplies multiple goods and services, and conservation or re-establishment of mangroves provides many benefits. International law and within-country environmental frameworks offer increasing scope to recognize the role that mangrove forests play through carbon sequestration, in order that these might lead to funding opportunities, both in public and private sectors. Such schemes need to have positive rather than negative impacts on the livelihoods of the many people living within and adjacent to these wetlands. Nevertheless, many challenges remain and it will require further targeted and coordinated scientific research, development of economic and social incentives to protect and restore mangroves, supportive law and policy mechanisms at global and national levels, and establishment of long-term financing for such endeavours.