Recruitment dynamics of the grove-dominant tree Microberlinia bisulcata in African rain forest: extending the light response versus adult longevity trade-off concept

In groves of ectomycorrhizal caesalpiniaceous species in the Atlantic coastal forest of Central Africa the dominant tree Microberlinia bisulcata, which is shade-intolerant as a seedling but highly light-responding as a sapling, shows very limited regeneration. M. bisulcata saplings were mapped in an 82.5-ha plot at Korup and found to be located significantly far (>40 m) away from adults, a result confirmed by direct testing in a second 56-ha plot. Sapling growth over 6 years, the distribution of newly emerging seedlings around adults, recruitment of saplings in a large opening and the outward extent of seedlings at the grove edge were also investigated. Two processes appear to have been operating: (1) a very strong and consistent restriction of the very numerous seedlings establishing after masting close to adults, and (2) a strong but highly spatially variable promotion of distant survivors by increased light from the deaths of large trees of species other than M. bisulcata (which itself has very low mortality rate). This leads to an apparent escape-from-adults effect. To maintain saplings in the shade between multiple short periods of release ectomycorrhizal connections to other co-occurring caesalp species may enable a rachet-type mechanism. The recorded sapling dynamics currently contribute an essential part of the long-term cycling of the groves. M. bisulcata is an interesting example of an important group of tropical trees, particularly in Africa, which are both highly light-demanding when young yet capable also of forming very large forest emergents. To more comprehensively explain tropical tree responses, the case is made for adding a new dimension to the trade-off concept of early tree light-response versus adult longevity.

Beyond megaprojects?. Water alternatives for mass tourism in coastal Mediterranean Spain

Water availability in adequate quantities and qualities is a fundamental requirement for tourism. In the Mediterranean, one of the world’s leading tourist destinations, water availability is subject to modest and erratic precipitation figures which may decline with climate change. The tourist industry therefore may have to assure future supplies by either recurring to new technologies such as desalination or increasing efficiency in water use. A third and yet little explored alternative would be to seek for complementary of uses with irrigation, the traditional user in many coastal Mediterranean areas and holder of substantial amounts of water. In this paper we present the example of the Consorcio de Aguas de la Marina Baja to show how Benidorm, in Mediterranean Spain and one of the most important tourist centers of the Mediterranean, obtains part of its water through agreements with farmers by which these trade their water with Benidorm and other towns’ treated wastewater of enough quality to be used for irrigation, and obtain several compensations in return. The advantages and disadvantages of the water trade between farmers and tourist interests in the Benidorm area are discussed and we argue that solutions to the pending water crisis of many coastal Mediterranean tourist areas may not need to rely uniquely on expensive technologies to generate new resources but may attempt other alternatives.

How coastal strategic planning reflects interrelationships between ecosystem services: a four-step method

Explicit and integrated inclusion of ecosystem services (ESs) and their interrelationships can improve the quality of strategic plans and decision-making processes. However, there is little systematic analysis of how ES interrelationships are framed in policy language, particularly in coastal planning discourse. The objective of this paper is therefore to present a four-step method, based on content analysis, to assess ES interrelationships in coastal strategic planning documents. The method consists of: 1) selecting strategic plans; 2) identifying ESs; 3) identifying drivers, ESs and their effects; and 4) constructing relational diagrams. The four-step method is applied to a case of Jiaozhou Bay in China, demonstrating its capacity of identifying which drivers and ES trade-offs and synergies are formulated in coastal strategic plans. The method is helpful to identify overlooked ES interrelationships, inform temporal and spatial issues, and assess the continuity of plans' attention to interrelationships. The main methodological contributions are discussed by emphasizing its broad scope of drivers and ESs and an explicit distinction among the cause of relationships. The developed method also has the potential of cross-fertilizing other kinds of approaches and facilitating practical planning processes.

Restoration ecology of coastal lagoons: new methods for the prediction of ecological trajectories and economic valuation

Conservation of the seven lagoons of the Palavas complex (southern France) has been severely impaired by nutrient over-enrichment during at least four decades. The effluents of the Montpellier wastewater treatment plant (WWTP) represented the main nutrient input. To improve the water quality of these lagoons, this WWTP was renovated and upgraded and, since the end of 2005, its effluents have been discharged 11 km offshore into the Mediterranean (total investment €150 M). Possibilities of ecosystem restoration as part of a conservation programme were explored by a focus group of experts. Their tasks were: (i) to evaluate the impact of the reduction of the nutrient input; (ii) if necessary, to design additional measures for an active restoration programme; and (iii) to predict ecosystem trajectories for the different cases. Extension of Magnoliophyta meadows can be taken as a proxy for ecosystem restoration as they favour the increase of several fish (seahorse) and bird (ducks, swans, herons) species, albeit they represent a trade-off for greater flamingos. Additional measures for active ecosystem restoration were only recommended for the most impaired lagoon Méjean, while the least impaired lagoon Ingril is already on a trajectory of spontaneous recovery. A multiple contingent valuation considering four different management options for the Méjean lagoon was used in a pilot study based on face-to-face interviews with 159 respondents. Three levels of ecosystem restoration were expressed in terms of recovery of Magnoliophyta meadows, including their impact on emblematic fish and avifauna. These were combined with different options for access (status quo, increasing access, increasing access with measures to reduce disturbance). The results show a willingness of local populations to pay per year about €25 for the highest level of ecological restoration, while they were only willing to allocate about €5 for additional footpaths and hides.

Regional drivers of clutch loss reveal important trade-offs for beach-nesting birds

Coastal birds are critical ecosystem constituents on sandy shores, yet are threatened by depressed reproductive success resulting from direct and indirect anthropogenic and natural pressures. Few studies examine clutch fate across the wide range of environments experienced by birds; instead, most focus at the small site scale. We examine survival of model shorebird clutches as an index of true clutch survival at a regional scale (∼200 km), encompassing a variety of geomorphologies, predator communities, and human use regimes in southeast Queensland, Australia. Of the 132 model nests deployed and monitored with cameras, 45 (34%) survived the experimental exposure period. Thirty-five (27%) were lost to flooding, 32 (24%) were depredated, nine (7%) buried by sand, seven (5%) destroyed by people, three (2%) failed by unknown causes, and one (1%) was destroyed by a dog. Clutch fate differed substantially among regions, particularly with respect to losses from flooding and predation. ‘Topographic’ exposure was the main driver of mortality of nests placed close to the drift line near the base of dunes, which were lost to waves (particularly during storms) and to a lesser extent depredation. Predators determined the fate of clutches not lost to waves, with the depredation probability largely influenced by region. Depredation probability declined as nests were backed by higher dunes and were placed closer to vegetation. This study emphasizes the scale at which clutch fate and survival varies within a regional context, the prominence of corvids as egg predators, the significant role of flooding as a source of nest loss, and the multiple trade-offs faced by beach-nesting birds and those that manage them.