Evaluating conservation and fisheries management strategies by linking spatial prioritization software and ecosystem and fisheries modelling tools

Well-designed marine protected area (MPA) networks can deliver a range of ecological, economic and social benefits, and so a great deal of research has focused on developing spatial conservation prioritization tools to help identify important areas. However, whilst these software tools are designed to identify MPA networks that both represent biodiversity and minimize impacts on stakeholders, they do not consider complex ecological processes. Thus, it is difficult to determine the impacts that proposed MPAs could have on marine ecosystem health, fisheries and fisheries sustainability. Using the eastern English Channel as a case study, this paper explores an approach to address these issues by identifying a series of MPA networks using the Marxan and Marxan with Zones conservation planning software and linking them with a spatially explicit ecosystem model developed in Ecopath with Ecosim. We then use these to investigate potential trade-offs associated with adopting different MPA management strategies. Limited-take MPAs, which restrict the use of some fishing gears, could have positive benefits for conservation and fisheries in the eastern English Channel, even though they generally receive far less attention in research on MPA network design. Our findings, however, also clearly indicate that no-take MPAs should form an integral component of proposed MPA networks in the eastern English Channel, as they not only result in substantial increases in ecosystem biomass, fisheries catches and the biomass of commercially valuable target species, but are fundamental to maintaining the sustainability of the fisheries. Synthesis and applications. Using the existing software tools Marxan with Zones and Ecopath with Ecosim in combination provides a powerful policy-screening approach. This could help inform marine spatial planning by identifying potential conflicts and by designing new regulations that better balance conservation objectives and stakeholder interests. In addition, it highlights that appropriate combinations of no-take and limited-take marine protected areas might be the most effective when making trade-offs between long-term ecological benefits and short-term political acceptability.

Hardpan and maize root distribution under conservation and conventional tillage in Agro-Ecological Zone IIA, Zambia

Hardpans (plough/hoe pans) are commonly believed to restrict plant root growth and crop yields under conventional small-scale agriculture in sub-Saharan Africa. This study questions the notion of widespread hardpans in Zambia and their remedy under conservation tillage. Soil penetration resistance was measured in 8x12 grids, covering 80 cm wide and 60 cm deep profiles in 32 soil pits. Large and fine maize roots were counted in 8x6 grids. Soil samples from mid-rows were analysed for pH, exchangeable H+, exchangeable Al3+, cation exchange capacity, total N and extractable P (Bray 1) at six depths from 0-10 to 50-60 cm. Cultivation-induced hardpans were not detected. Soils under conservation tillage were more compact at 5 cm depth than soils under conventional tillage. No differences in root distributions between conservation and conventional tillage were found. Maize ( Zea mays L. ) roots were largely confined to a relatively small soil volume of about 30 cm x 30 cm x 30 cm. Root growth appeared to be restricted by a combination of low concentrations of N and P. Soil acidity and Al saturation appeared to play a minor role in root distribution. L-shaped taproots in soils under manual tillage reported earlier were not necessarily due to hardpans, but may rather be caused by temporarily dry, impenetrable subsoils early in the rain season. There is no scientific basis for the recommendation given to farmers by agricultural extension workers to “break the hardpan” in fields under manual or animal tillage in the study areas.

FIELD TOLERANCE OF SELECTED VARIETIES TO AND FUNGICIDE EFFICACY AGAINST ALTERNARIA BLIGHT OF SWEET POTATO

Alternaria blight (AB) of sweet potato ( Ipomoea batatas L. ), caused by Alternaria spp., was recently reported in South Africa, but is common in southern and eastern Africa. Elsewhere in the world, AB is controlled primarily using resistant varieties. Twenty-five sweet potato varieties/breeding lines, from different origins were assessed for tolerance to AB. The materials were planted in fields having a history of AB disease and rated for tolerance based on a General Disease Index (GDI), with the lowest scores representing tolerance, and the higher scores representing susceptibility. Variety 199062-1 had the lowest GDI value, and was the most tolerant to AB; while W119 had the highest GDI value and was the most susceptible to the disease. Other varieties/breeding lines showed a variation in GDI values between most tolerant and most susceptible. Among the fungicides tested under field conditions, the mixture azoxystrobin-difenoconazole was the most effective in reducing AB intensity. Fungicides pyraclostrobin-boscalid, unizeb, azoxystrobin-chlorothalonil and cymoxanil-mancozeb were also effective against the disease.

Conservation and management of exploited shark populations based on reproductive value

Several life history traits of sharks result in juveniles being particularly vulnerable to exploitation. However, population level impacts of harvests on juvenile sharks have not been well quantified. This paper examines a range of harvest strategies, including those targeting juveniles. Reproductive value and yield per recruit are used to compare the harvests, which are represented by Leslie matrix models with a harvest matrix. Two species are used as examples: the short-lived Rhizoprionodon taylori and the long-lived Squalus acanthias. Harvests that maintain a stationary population size cause reproductive values to change in opposing ways, but they remove equal fractions of the population's reproductive potential. A new theorem gives population growth as a function of the fraction of reproductive potential removed by a harvest, a relationship useful for comparing harvests on juveniles and adults. Stochastic projections indicate that the risk of depletion is associated with the fraction of reproductive potential removed annually, a measure which encompasses the information in both the selectivity and the rate of fishing mortality. These results indicate the value of focusing conservation efforts on preserving reproductive potential.

Quantifying recreational shore angling catch and harvest in southern Portugal (north-east Atlantic Ocean): implications for conservation and integrated fisheries management

Recreational shore fishing along 250 km of the south and south-west coast of Portugal was studied based on roving creel and aerial surveys. Surveys were conducted between August 2006 and July 2007, following a stratified random-sampling design and provided information on catch and effort, harvest and discards, angler demographics and fishing habits. Overall, 192 roving creel surveys, 24 aerial surveys and 1321 interviews were conducted. Based on the aerial surveys, a mean +/- s.e. total fishing effort of 705 236 +/- 32 765 angler h year(-1) was estimated, corresponding to 166 430 +/- 9792 fishing trips year(-1). Average time spent per fishing trip was 4.7 h. A total of 48 species, belonging to 22 families, were recorded in roving creel surveys. The most important species was Diplodus sargus, accounting for 44% of the total catches by number and 48% by mass. Estimated mean +/- s.e. total annual recreational shore fishing catch was 160.2 +/- 12.6 t year(-1) (788 049 +/- 54 079 fishes year(-1)), of which 147.4 +/- 11.9 t year(-1) (589 132 +/- 42 360 fishes year(-1)) was retained. Although overall shore-based recreational catches only corresponded to 0.8% of the commercial landings (only common species considered), D. sargus catches by recreational shore anglers were considerable, corresponding to 65% of the commercial landings. The implications of these results for integrated fisheries management and conservation are discussed, and future research proposed.

Trophic signatures of small-scale fishing gears: implications for conservation and management

We quantified the ecosystem effects of small-scale gears operating in southern European waters (Portugal, Spain, Greece), based on a widely accepted ecosystem measure and indicator, the trophic level (TL). We used data from experimental fishing trials during 1997 to 2000. We studied a wide range of gear types and sizes: (1) gill nets of 8 mesh sizes, ranging from 44 to 80 mm; (2) trammel nets of 9 inner panel mesh sizes, ranging from 40 to 140 mm; and (3) longlines of 8 hook sizes, ranging from Nos. 15 (small) to 5 (large). We used the number of species caught per TL class for constructing trophic signatures (i.e. cumulative TL distributions), and estimated the TL at 25, 50 and 75% cumulative frequency (TL25, TL50, TL75) and the slopes using the logistic function. We also estimated the mean weighted TL of the catches (TLW). Our analyses showed that the TL characteristics of longlines varied much more than those of gill and trammel nets. The longlines of large hooks (Nos. 10, 9, 7, 5) were very TL selective, and their trophic signatures had very steep slopes, the highest mean TL50 values, very narrow mean TL25 to TL75 ranges and mean TLW > 4. In addition, the mean number of TL classes exploited was smaller and the mean TL50 and TLW were larger for the longlines of small hooks (Nos. 15, 13, 12, 11) in Greek than in Portuguese waters. Trammel and gill nets caught more TL classes, and the mean slopes of their trophic signatures were significantly smaller than those of longlines as a group. In addition, the mean number of TL classes exploited, the mean TL50 and the TLW of gill nets were significantly smaller than those of trammel nets. We attribute the differences between longlines of small hooks to bait type, and the differences between all gear types to their characteristic species and size-selectivity patterns. Finally, we showed how the slope and the TL50 Of the trophic signatures can be used to characterise different gears along the ecologically 'unsustainable-sustainable' continuum.

Exploited anadromous fish in Portugal: Suggested direction for conservation and management.

Sea lamprey (Petromyzon marinus) and allis shad (Alosa alosa) have been fished for centuries in mainland Portugal during their upstream spawning migration. Here, biological information is compared for the two species and governance and monitoring data from Portugal are reviewed to propose species-specific courses of future action. Despite a national fisheries legislation common for the two species and the designation of Sites of Community Interest (SCIs) for both, the current conservation needs for sea lamprey and allis shad in Portugal are considered to be distinct. For sea lamprey, conservation priorities must focus on planning fisheries managementinarticulationwithhabitatrecoverytoguaranteecost-effective monitoring andsustainablelong-termexploitationthataddsvaluetolocalcommunitiesandpaysdue taxation. Onthecontrary,conservationconcernsandactionsforallisshadmuststrengthenandbemore proactive in the reduction of fishing mortality, both target (in rivers) and by catch (at sea).There is a need to make better use of the opportunities inherent in the Habitats Directive and the possibility to define specific management actions within SCIs. To this effect, it will be necessary to revise existing legislation and guarantee better articulation between jurisdictional authorities. A good example in this direction is the articulation already established in the river Mondego where habitat restoration, fish monitoring and effective species-specific fisheries control measures have been taken and implemented in recent years by a large institutional partnership.

Solutions for the conservation and restoration of cement-based materials in XX Century architectural heritage

Among the most representative materials of XX Century architectural heritage, this dissertation focuses on the cement-based ones, investigating some different fields where they were exploited. Primarily, concerning the surface preservation of cement-based materials used with aesthetic intent, new self-cleaning treatments based on titania nanoparticles embedded in inorganic matrices were tested. In order to consider the role of porosity, the treatments were applied to different kinds of materials (cement-based mortar, marble and concrete) and several analyses were conducted to investigate the morphology of the coatings, their photocatalytic effectiveness, their durability and the interaction between the coating and the substrate material. The outcomes showed that several parameters influence the treatment’s performances, in particular, the presence and nature of the matrix, the concentration and dispersion of nanoparticles and, in some cases, the amount of substrate material which interacts with the coatings. Secondly, this dissertation deals with the historic “Terranova” render, a colored dry-mix mortar largely widespread in Europe in the first half of XX Century, whose formulation is still basically unknown. Some original samples of supposedly Terranova renders were subjected to several characterization analyses and the results were compared to those of the original “Terranova” render of the Engineering Faculty in Bologna. Despite the recurrence of some features, defining a common formulation seemed to be challenging. Finally, the repair and conservation of structural reinforced concrete in heritage buildings were investigated, adopting the former “Casa del Fascio” in Predappio (FC, Italy) as case study. Three different materials and solutions were tested on a slab of the building, making its repair only from the intrados. Then several analyses were conducted both on site and in laboratory. Aside from the specific features characterizing every product, the results highlighted that the application method played a fundamental role in the effectiveness of the retrofit strategies.

Knowledge and willingness to pay for the conservation of wildlife species: Experimental results evaluating Australian tropical species

The nature of an experiment involving 204 residents is outlined and the results are reported and analysed. Two consecutive surveys of the respondents provide data about their stated knowledge of 23 wildlife species present in tropical Australia, most of which exclusively occur there. In addition, these surveys provide data about the willingness of respondents to pay for the conservation of those species belonging to three taxa; reptiles, mammals, and birds. Thus it is possible to compare the respondents’ stated knowledge of the species with their willingness to pay for their conservation, and to draw relevant inferences from this. From the initial survey and these associations, interesting relationships can be observed between those variables (knowledge and willingness to pay). The second survey was completed after the respondents’ knowledge of the species was experimentally increased and became more balanced. This is shown to result in increased dispersion (greater discrimination) in willingness to contribute to conservation of the different species in the set of wildlife species considered. Both theoretical and policy conclusions are drawn from the results.

Disease, habitat fragmentation and conservation

Habitat loss and the resultant fragmentation of remaining habitat is the primary cause of loss of biological diversity. How do these processes affect the dynamics of parasites and pathogens? Hess has provided some important insights into this problem using metapopulation models for pathogens that exhibit 'S-I' dynamics; for example, pathogens such as rabies in which the host population may be divided into susceptible and infected individuals. A major assumption of Hess's models is that infected patches become extinct, rather than recovering and becoming resistant to future infections. In this paper, we build upon this framework in two different ways: first, we examine the consequences of including patches that are resistant to infection; second, we examine the consequences of including a second species of host that can act as a reservoir for the pathogen. Both of these effects are likely to be important from a conservation perspective. The results of both sets of analysis indicate that the benefits of corridors and other connections that allow species to disperse through the landscape far outweigh the possible risks of increased pathogen transmission. Even in the commonest case, where harmful pathogens are maintained by a common reservoir host, increased landscape connectance still allows greater coexistence and persistence of a threatened or endangered host.