The Semiglades: the collision of restoration, social values, and the ecosystem concept

Opinion article

Comparative studies on the structure of an upland African stream ecosystem

Upland stream systems have been extensively investigated in Europe, North America and Australasia and many of the central ideas concerning their function are based on these systems. One central paradigm, the river continuum concept is ultimately derived from those North American streams whose catchments remain forested with native vegetation. Streams of the tropics may or may not fit the model. They have been little studied. The Amani Nature Reserve in the East Usambara Mountains of north-eastern Tanzania offers an opportunity to bring these naturally forested systems to the attention of the ecological community. This article describes a comparison made between two lengths of the River Dodwe in this area. The work was carried out by a group of postgraduate students from eighteen European and African countries with advice from five staff members, as part of a course organised by the Tropical Biology Association. Rigorous efforts were made to standardise techniques, in a situation where equipment and laboratory facilities were very basic, through a management structure and deliberate allocation of work to specialists in each area.The article offers a summary of invertebrate communities found in the stream and its biomass. Crabs seem to be the key organism in both sections of the streams.

Towards integrated island management: lessons from Lau, Malaita, for the implementation of a national approach to resource management in Solomon Islands: final report

Solomon Islands has recently developed substantial policy aiming to support inshore fisheries management, conservation, climate change adaptation and ecosystem approaches to resource management. A large body of experience in community based approaches to management has developed but “upscaling” and particularly the implementation of nation-wide approaches has received little attention so far. With the emerging challenges posed by climate change and the need for ecosystem wide and integrated approaches attracting serious donor attention, a national debate on the most effective approaches to implementation is urgently needed. This report discusses potential implementation of “a cost-effective and integrated approach to resource management that is consistent with national policy and needs” based on a review of current policy and institutional structures and examination of a recent case study from Lau, Malaita using stakeholder, transaction and financial cost analyses.

Distributions and abundances of Pacific sardine (Sardinops sagax) and other pelagic fishes in the California Current Ecosystem during spring 2006, 2008, and 2010, estimated from acoustic–trawl surveys

The abundances and distributions of coastal pelagic fish species in the California Current Ecosystem from San Diego to southern Vancouver Island, were estimated from combined acoustic and trawl surveys conducted in the spring of 2006, 2008, and 2010. Pacific sardine (Sardinops sagax), jack mackerel (Trachurus symmetricus), and Pacific mackerel (Scomber japonicus) were the dominant coastal pelagic fish species, in that order. Northern anchovy (Engraulis mordax) and Pacific herring (Clupea pallasii) were sampled only sporadically and therefore estimates for these species were unreliable. The estimates of sardine biomass compared well with those of the annual assessments and confirmed a declining trajectory of the “northern stock” since 2006. During the sampling period, the biomass of jack mackerel was stable or increasing, and that of Pacific mackerel was low and variable. The uncertainties in these estimates are mostly the result of spatial patchiness which increased from sardine to mackerels to anchovy and herring. Future surveys of coastal pelagic fish species in the California Current Ecosystem should benefit from adaptive sampling based on modeled habitat; increased echosounder and trawl sampling, particularly for the most patchy and nearshore species; and directed-trawl sampling for improved species identification and estimations of their acoustic target stren

Indicators for management of coral reefs and their applications to marine protected areas

Informed planning and decision-making in the management of natural resources requires an ability to integrate complex interactions in ecosystems and communicate these effectively to stakeholders. This involves coping with three fundamental dilemmas. The first comes from the irregular pulse of nature. The second is the recognition that there are no strictly objective criteria for judging the well-being of an ecosystem. The third is posed by the quest for indicators with some integrative properties that may be used to analyze an ecosystem and impart the information to the relevant resource users. This paper presents some examples of indicators used to: 1) assess the status of a coral reef and, in particular, the state of its fisheries resources; 2) identify reefs that are most threatened by human activities; and 3) evaluate the likelihood of success of management interventions. These indicators are not exhaustive, but illustrate the range of options available for the management of coral reef ecosystems.

Indicators for management of coral reefs and their applications to marine protected areas

Informed planning and decision-making in the management of natural resources requires an ability to integrate complex interactions in ecosystems and communicate these effectively to stakeholders. This involves coping with three fundamental dilemmas. The first comes from the irregular pulse of nature. The second is the recognition that there are no strictly objective criteria for judging the “well-being” of an ecosystem. The third is posed by the quest for indicators with some integrative properties that may be used to analyze an ecosystem and impart the information to the relevant resource users. This paper presents some examples of indicators used to: 1) assess the status of a coral reef and, in particular, the state of its fisheries resources; 2) identify reefs that are most threatened by human activities; and 3) evaluate the likelihood of success of management interventions. These indicators are not exhaustive, but illustrate the range of options available for the management of coral reef ecosystems.

USA rethinks fisheries management

Fisheries in the USA are managed under the Magnuson Fishery Conservation and Management Act of 1976 (MFCMA). By 1991, it was reported that fish stocks had declined considerably since the act came into force. A national Committee in Fisheries was set up in 1992 to investigate ways of improving fisheries management regimes. The committee's seven recommendations framed in four broad areas are: (1) prevent overfishing; (2) improve the institutional structure; (3) improve the quality of fishery science and data; and (4) move toward an ecosystem approach to fishery management. These recommendations are designed to enchance the most effective aspects of the present MFCMA and to introduce critically needed clarifications and structured improvements.

The South China Sea: analyzing fisheries catch data in an ecosystem context

The South China Sea is an important fishing area with an annual harvest of some 5 million tonnes, or 10% of the catches jointly taken by the developing nations of the world. Details are given of a model of the area describing fisheries catches and biological interactions. The area, viewed as a large marine ecosystem, was divided into 10 subsystems; each subsystem was then linked with adjacent subsystems by predatory links, and detritus flows. An analysis was then made of catch statistics for each of the subsystems. It is believed that if all systems could be harvested at around the highest efficiency, an additional 5-6 million tonnes could be taken annually from the South China Sea; however, more refined analyses are needed to further investigate these possibilities. If linked with careful studies of the economic and human aspects of fishing, such analyses will provide guidelines for integrated fisheries management advice.

Management of mangrove areas in Calauag Bay, Quezon Province, Philippines

The findings are presented of a study conducted in Calauag Bay, Quezon Province, Philippines in order to estimate resource rent of mangrove areas converted to fishpond production. The rents were calculated based on the technology practised by the farmers and the prices of inputs and outputs that prevailed during the study period. The major causes of mangrove depletion are cutting of mangroves for fuelwood and charcoal and clearing for fishpond development. It was concluded that there is justification for the government to increase the feed which could be used to rehabilitate the inland-coastal fisheries to improve productivity and ensure sustainability of the ecosystem for future generations.

Multidisciplinary research and management: fisheries in the Central Delta of the Niger River (Mali)

This contribution gives an overview of the fisheries in the Central Delta of the Niger River (Mali) and highlights the results of a multidisciplinary research and management program conducted in the area to assess the status of the fisheries and improve their management. The importance of multidisciplinary approaches is emphasized to fully elaborate the problems impacting fisheries and the measures for their resolution. Directions for increased decentralization, participation of fishers and ecosystem preservation for improved management of the Central Delta fisheries are briefly discussed.

The Ahupua'a concept: relearning coastal resource management from ancient Hawaiians

Isolated in the middle of the Pacific Ocean, Hawaii was one of the last areas to be reached by "western" explorers; as a consequence, some ancient traditions were preserved in Hawaii well into the 19th and 20th centuries, providing an opportunity to learn from a surviving indigenous culture. An account is given of the division of the islands into various units and their exploitation. The smallest major divisions were the "ahupua'as," which spread out at the base along the shore and were self-sufficient units. In this way the ancient Hawaiians recognized the relationship between the land and sea, rainfall and vegetation, nutrients and runoff and preserved the integrity of the delicately balanced ecosystem of which they were a part and upon which they relied for their every need. Modern parallels to this ancient system are broken and irregular; the reorganization of the "ahupua'a" system marked the beginning of the decline of Hawaiian ecosystems. Although steps are being taken to remedy the present situation, Hawaii now ranks among the highest in the nation for its levels of pollution, endangered species and disappearing habitats. More and more, the model for improved management is being sought in the revival of ancient traditions.

An Assessment of Fishery Yields from the East China Sea Ecosystem

A first assessment ofimportant East China Sea fisheries was carried out using data from 1956 to 1993. Two different data sets were available: 1) catch and effort data taken from landings and boat registrations and 2) catch and effort data from skipper's logs taken at sea. The two sets provided similar trends in CPUE over the study period. Stocks of high value, low volume species have been fished heavily and now produce very low landings or have been depleted (e.g. small and large yellow croaker). Some high volume and low value species have also been heavily fished (e.g. green filefish) while others (e.g. hairtail) are still producing high landings. Surplus production models were fitted to seven stocks. All showed considerable fluctuations in landings around MSY. The green filefish stock had an estimated MSY of around 160,000 tlyr at an effort of 2,500,000 kw and was depleted by a combination of excessive effort (around 4,000,000 kw in 1993) and marked fluctuations in landings (up to 70,000 tlyr above or below MSY). A sustainable policyfor managing ECS fisheries should address the effects ofboth effort and environmental variation.

Participatory action research on climate risk management, Bangladesh

The rural populations of southern Bangladesh are some of the most vulnerable communities in the world to the future impacts of climate change. They are particularly at risk from floods, waterlogged soils, and increasing salinity of both land and water. The objective of this project was to analyze the vulnerability of people in four villages that are experiencing different levels of soil salinity. The study evaluated the strengths and weaknesses of current coping strategies and assessed the potential of an index-based insurance scheme, designed diversification and better information products to improve adaptive capacity.

Episodic variations in stream water chemistry associated with acid rainfall and run-off and the effect on aquatic ecosystem, with particular reference to fish populations in N.W. England

This is the episodic variations in stream water chemistry associated with acid rainfall and run-off and the effect on aquatic ecosystems, with particular reference to fish populations in North West England produced by the North West Water Authority in 1985. This report looks at the biological, physical and chemical information collected over a five year period from over 100 sites on upland streams in the North West Region of which drained rocks of low buffering capacity. In both Lake District and South Pennine sites striking differences were found between the composition of invertebrate communities inhabiting acid-stressed and less acid-stressed streams. Electric fishing surveys showed that acidic streams (geometric mean pH <5.5) generally had abnormally low densities of salmonids ( < 0 .2m2) and that 0+ fish were very few or absent. The latter indicates recruitment failure. Salmon were more sensitive than trout to low pH.