Wider Ecosystem Research Articles

Estimating dry matter content from spectral reflectance for green leaves of different species

Efficient and accurate detection of the temporal dynamics and spatial variations of leaf dry matter content would help monitor key properties and processes in vegetation and the wider ecosystem. However, leaf water content strongly absorbs at shortwave infrared wavelengths, reducing the signal from dry matter. The major objective of this study was to examine relationship between spectral reflectance of fresh leaves and the ratio of leaf dry mass to leaf area, across a wide range of species at the leaf scale. A narrow-band, normalized index combining two distinct wavebands centred at 1649 and 1722 nm achieved the highest overall performance and discriminatory power compared to either single band or first derivatives. The normalized index was evaluated using the PROSPECT (leaf optical properties spectra) simulated reflectance spectra and field measurements from the Leaf Optical Properties Experiment (LOPEX) data set. Both evaluations show that leaf dry matter contents were retrievable with R 2 of 0.845 and 0.681 and regression slopes of 0.903 and 0.886. This study suggests that spectral reflectance measurements hold promise for the assessment of dry matter content for green leaves. Further investigation needs to be conducted to evaluate the effectiveness of this normalized index at canopy scales.

The Impact of Farmer Field Schools on Human and Social Capital: A Case Study from Ghana

Based on a case study of Ghanaian cocoa farmers who attended farmer field schools (FFS), this paper explores the impact of the FFS methodology on farmers’ technical knowledge, experimentation, knowledge diffusion, group formation and social skills as a way of assessing whether the relatively high costs associated with the method is justified. We carried out focus group discussions for exploratory purposes and a formal survey of 70 FFS graduates and 70 non-FFS farmers. The superior knowledge test scores of FFS graduates relative to non-FFS farmers demonstrates the effectiveness of the method for communicating complex knowledge and information to farmers in a way that allows them to understand it and retain it. An assessment of changes in farmers’ experimental capacity showed variable results. On the one hand, a significant proportion of FFS graduates applied some of the principles and practices learned to solve productivity problems with other crops, while others did not perceive any change in their experimentation behaviour. Significantly, an important skill farmers learned in the FFS was making observations on cocoa trees and the wider ecosystem as the basis for decision-making. The case study confirmed that FFS strengthened social cohesion among cocoa farmers and enhanced individual social skills by creating new networks for knowledge exchange and support, promoting group formation and improving farmers’ confidence and ability to work more effectively in groups. The paper concludes by recommending areas for improving FFS and highlights how strengthening human and social capital in cocoa growing communities can serve as a springboard for broader development activities.

Veterinarians and Taxonomic Chauvinism: The Dilemma of Parasite Conservation

Abstract Preservation of biodiversity is one of the fundamental objectives of conservation. Animal conservation programs, however, tend to be dominated by charismatic vertebrate species. Many parasites are highly specialized, having evolved to depend on a single species and may be rarer and hence more endangered than their specific hosts. The phenomenon of coextinction, in which there is the loss of affiliated species such as parasites, needs consideration if conservation is not to fall victim to taxonomic chauvinism. Broad-spectrum antiparasitic drugs when used in free-living wildlife can have an effect on nontargeted species and the wider ecosystem. It is also recognized that parasites may have a role to play in the normal functioning of a host's immune system when the two have coevolved over an extended period of time. Although the concept of parasite conservation is in itself controversial, this is further complicated when deciding to which areas of conservation medicine it should apply.

The risk to fishery performance associated with spatially resolved management of Antarctic krill (Euphausia superba) harvesting

Abstract Hill, S. L., Trathan, P. N., and Agnew, D. J. 2009. The risk to fishery performance associated with spatially resolved management of Antarctic krill (Euphausia superba) harvesting. – ICES Journal of Marine Science, 66: 2148–2154. The ecosystem approach to fisheries attempts to define objectives for target species, the wider ecosystem, and critically, the fishery itself. Proposals for implementing the approach often include spatial restrictions on harvesting, so it is important to understand how these will affect fishery performance. One metric of potential performance is the probability of encountering exploitable densities of a target species at the scale of fishing operations. The probability of encountering exploitable densities of Antarctic krill, Euphausia superba, at the scale of 1 nautical mile during an acoustic survey was predicted by bathymetry and the mean krill density at the larger scale at which the fishery is managed. This suggests that the risk to fishery performance will increase if management actions relocate the fishery into deeper water. The results also suggest that ecosystem models resolved to the spatial scale of management units could usefully predict effects at the scale of fishing operations. However, correct parameterization of these models will require better characterization of threshold densities for efficient exploitation. Finally, the distribution of catch and fishing effort over an entire fishing season reflected the distribution of krill density observed during the survey.

Sustained by Snakes? Seasonal Livelihood Strategies and Resource Conservation by Tonle Sap Fishers in Cambodia

This paper situates concerns for conservation of aquatic snakes and livelihood sustainability in Cambodia within a social–ecological systems context and thereby presents a challenge to conventional species-based conservation programmes. Fishing for low-value water snakes has become a widespread activity within the floating communities of Tonle Sap Lake in the last 20 years in response to new market opportunities, provided primarily by a crocodile farming industry. The scale and intensity of this new form of exploitation and reports of declines in catch per fisher have highlighted this activity as a conservation concern, yet its role within local livelihood strategies was previously unknown. We show that it is of increasing importance to the less well-off, and is linked to higher incomes within this group, where it potentially reduces their vulnerability to fluctuations and declines in fish catches. It is particularly important as a means to smooth seasonality of incomes in this flood pulse-driven social–ecological system. We argue that shifts between snake-hunting and fishing, as a market-driven adaptive livelihood strategy by the poor, may be more compatible with wider ecosystem conservation and development goals than alternatives such as increased fishing effort or converting floodplain habitats for seasonal agriculture.

Problems in the interpretation of Brazilian archaeofaunas: Different contexts and the important role of taphonomy

Studies on Brazilian archaeofauna from prehistoric and historic sites have attempted to explain human settlement and cultural trajectories in different geographical regions. However, only since 1999 have taphonomical criteria been developed during Brazilian zooarchaeological investigations. Wide ecosystem diversity results in the differential preservation of faunal remains. Until the end of the 20th century, many zooarchaeological studies presented insufficient information on complex predator–prey interaction systems in many regions, mostly from the Amazonian lowlands and the highlands of the Central Plateau. Animal remains might have been the result of natural predation, and they are often found mixed within anthropic material that could distort interpretation of deposits. Thus, there are major problems in defining diagnostic criteria to distinguish natural from cultural marks. Taphonomic analyses are needed to explain faunal remains in order to understand the particularities of human–animal relationships in Brazilian prehistory. Zooarchaeological and taphonomical data are presented from five human occupation sites dating from 9000 to 1000 BP to verify human–fauna relationships and natural deposits in three different regions of Brazil. These sites illustrate both natural and anthropic contexts.

Nutrient enrichment and the role of salt marshes in the Tagus estuary (Portugal)

Eutrophication is one of the most common impacts of nutrient enrichment on coastal ecosystems. Since there is a wide ecosystem response variety in scale, intensity and impact to nutrient enrichment, the loading required to produce eutrophication symptoms to each system is also variable. In estuaries and coastal zones salt marsh primary producers have received less attention, mainly because salt marsh dominated systems are considered less sensitive to nutrient enrichment and, for that reason, their response is slower and more difficult to quantify. Salt marshes have been considered as major attenuators of the effects of nitrogen enrichment in several coastal systems, and are indicated as a measure of the system susceptibility to nutrient enrichment. The main goal of the present work is to discuss the role of salt marsh vegetation in the nutrient dynamics of coastal systems and in the nutrient enrichment process. For these purposes salt marsh vegetation growth in the Tagus estuary is described through a mathematical model which includes the simulation of the nutrient dynamics through the sediment–water interface and the uptake kinetics by the vascular plants. An analysis of the role of salt marsh vegetation on the nutrient dynamics of the Tagus estuary is carried out through the discussion of the model results and comparison with data obtained for other primary producers in the system. The results indicate that C 4 salt marsh plants have the highest productivity, followed by seaweeds. The total net production of salt marsh plants and is about 12,600 ton C yr −1, accounting for 25% of the total primary production within the system.

An exploration of the relationships betweenmacroinvertebrate community composition and physical andchemical habitat characteristics in farm dams

Recently, Australian interest in farm dams has focused on rates of harvest of surface waters (runoff), and the impact this has on nearby natural systems. Little research has been directed towards the role of these artificial water bodies in sustaining biological reserves within the wider ecosystem. Macroinvertebrate communities in three farm dams in the Central Tablelands of New South Wales were surveyed, and water quality variables were correlated with species richness and abundance. Community responses to habitat factors including sediment depth, stock use, vegetation and debris were also examined. Communities were described at several taxonomic levels in addition to allocation to trophic groups and primary functional feeding groups. Species richness and abundance of communities were found to vary between dams and between habitat types within dams. The extent of these differences was decreased when communities were described by either trophic status or functional feeding mechanisms. Habitats were influenced by water quality and by physical features of the habitat, with the two factors interacting to define equilibrium conditions. Localised conditions resulted in different macroinvertebrate communities. Physicochemical parameters that correlated most closely with communities included light penetration, chlorophyll-a and conductivity. Habitat factors that were most frequently linked with communities were sediment depth and canopy cover, with localised disturbances related to stock use affecting feeding groups rather than specific taxa. One of the major problems associated with increasing modification of landscapes by agriculture or urbanisation is the fragmentation of undisturbed habitats. Creation of joint aquatic and woodland habitats enhances biodiversity corridors. The recognition of the potential for farm dams as reservoirs of biodiversity and development of management practices that optimise this neglected biodiversity reserve may have much wider benefits biologically, aesthetically and productively.

Sacred groves of Manipur, northeast India:biodiversity value, status and strategies for their conservation

The people of Manipur, a state in northeast India, follow ancestral worship and animism in the form of deity worship, with the central focus on worship in forest patches. The beliefs and taboos associated with the Sylvan deities (Umanglais) in the forest patches are restricted to any sort of disturbance of flora and fauna. These social boundaries help to conserve the entire organism as a whole, which stand the concept of sacred groves. The pleasing of deities is performed every year by the Meiteis, a dominant community of Manipur, in honour of the deities and to gain their favour. Indigenous cultural and rituals practices of the local people in sacred groves serve as a tool for conserving biodiversity. Sacred groves are distributed over a wide ecosystem and help in conservation of rare and endemic species. Well-preserved sacred groves are store houses of valuable medicinal and other plants having high economic value, and serve as a refuge to threatened species. One hundred and sixty-six sacred groves were inventoried in Manipur valley that comprises Imphal east, Imphal west, Thoubal and Bishnupur districts of the state. Detailed studies were carried out in four selected sacred groves, to know the importance of biodiversity status and vegetation characteristics. A total of 173 plant species representing 145 genera under 70 families were recorded through baseline floristic survey. The species diversity indices were compared among the four studied groves. The vegetation composition and community characteristics were recorded. Ethnobotanical uses of species were examined, which reveal that 96% of the species were used as medicine for the treatment of various ailments. Utilization of herbal medicine by the Meiteis is closely related to the cultural and ritual practices. A few of the medicinal plants which have disappeared from the locality are now confined only to the groves. Socio-cultural aspects were investigated taking into account the attitudes of local people, which indicate social beliefs and taboo are eroding, simultaneously degrading the degree of protection of sacred groves. Therefore, conservation measures of sacred groves need to be formulated considering the factor of degradation and the basic necessities of the local people. Until and unless a viable option is provided to the local people (especially those who habitat nearby the adjoining areas) for sustaining their economic condition, no step for conservation of biodiversity will be successful.

Review of indicators in fisheries management – a development perspective

A review of indicators for an ecosystem approach to fisheries management is presented, focusing on multispecies fisheries and limited resources for assessments and implementation, as often is the case in developing countries. Emphasizing the need to link indicators to management objectives, indicators from the literature are grouped into four categories, relating to the immediate fisheries resource base (single-species and multispecies indicators) and the wider ecosystem (habitat structure and ecosystem functioning). The usefulness of these indicators is assessed along three dimensions of acceptability among stakeholders, observability, and relation to fisheries management using a traffic light approach. The top ranking indicators are highlighted as a generally good start for any particular fishery management case. It is, however, argued that, even with similar management objectives, indicators need to be specific to both ecosystems and the institutional set-up if they are to be effective for management, and that indicators may consequently differ considerably between individual management applications.

Integrating individual habitat choices and regional distribution of a biodiversity indicator and top predator

AbstractAim Habitat selection studies have mainly focused on behavioural choices of individuals or on the habitat‐related regional distribution of a population, with little integration of the two approaches. This is despite the fact that traditional biogeography theory sees the geographical distribution of a species as the collective outcome of the adaptive habitat choices of individuals. Here, we integrate individual habitat choices with regional distribution through a bottom‐up Geographical Information System (GIS)‐based approach, by using a 9‐year data set on a large avian predator, the eagle owl (Bubo bubo L.). We further examine the potential population level and biodiversity consequences of this approach.Location The study was conducted in the Trento Region (central‐eastern Italian Alps) and in six other areas of the nearby Lombardia Region in the central Alps.Methods We used stepwise logistic regression to build a habitat suitability model discriminating between eagle owl territories and an equal number of random locations. The model was applied to the whole Trento region by means of a GIS so as to predict suitable habitat patches. The predicted regional distribution (presence–absence in 10‐km grid quadrats) was then compared with the observed one. Furthermore, we compared estimates of biodiversity in quadrats with and without eagle owls, so as to test whether the presence of this top predator may signal macro‐areas of high biodiversity.Results The logistic habitat suitability model showed that, compared with a random distribution, eagle owls selected low‐elevation breeding sites with high availability of prey‐rich habitats in their surroundings. Breeding performance increased with the availability of prey‐rich habitats, confirming the adaptiveness of the detected habitat choices. We applied the habitat suitability model to the 6200 km2 study region by means of a GIS and found a close fit between the observed and predicted regional distribution. Furthermore, population abundance was positively related to the availability of habitat defined as suitable by the above analyses. Finally, high biodiversity levels were associated with owl presence and with the amount of suitable owl habitat, demonstrating that modelling habitat suitability of a properly chosen indicator species may provide key conservation information at the wider ecosystem level.Main conclusions Our bottom‐up modelling approach may increase the conservation‐value of habitat selection models, by (1) predicting local and regional distribution, (2) estimating regional population size, (3) stimulating further hypothesis testing, (4) forecasting the population effects of future habitat loss and degradation and (5) aiding in the identification and prioritization of high‐biodiversity areas.

Ecosystem effects of marine fisheries: an overview

Most fisheries literature avoids speaking about ecosystem impacts of fishing, either because impacts are not demonstrated or because a causal relationship between impacts and fishing cannot be formally established with the available information. However, there is mounting evidence that fishing has undesired effects in the marine ecosystems. This overview examines the wide ecosystem effects of fishing, describing and illustrating the potential unintended effects of the main fisheries of the world. An operational framework for classifying the effects of fishing in terms of the mechanisms generating the effects is provided. The focus and, to a large extent, the recourse to examples is on those fisheries for which the impacts of fishing have been best studied such as those in the North Atlantic and the Northeast Pacific. Ecosystem effects are divided into direct and indirect: direct effects include the fishing mortality exerted on target populations (overfishing), the fishing mortality sustained by non-target populations (bycatch), and the physical impacts caused by towed gears on benthic organisms and on the seabed. Indirect effects include impacts mediated by biological interactions, the environmental effects of dumping discards and organic detritus (offal), and the mortality caused by lost gear (ghost fishing).

The 1995 United Nations agreement on straddling fish stocks and highly migratory fish stocks: A critique

Problems associated with the failure of the United Nations Convention on the Law of the Sea to address adequately the management of straddling stocks have become readily apparent in the period since that treaty's adoption in 1982. The 1995 United Nations Agreement for the Conservation and Management of Straddling Fish Stocks and Highly Migratory Fish Stocks provides a significant attempt by the international community to deal with those problems. The new agreement incorporates the concept of precaution, strengthens the role of regional organizations in the management of straddling fish stocks, and encourages consideration of fisheries in a wider ecosystem context. While the provisions of the Straddling Stocks Agreement further develop and enhance the international law applicable to fishery management beyond that contained in the 1982 Law of the Sea Convention, a number of potential problems are posed as the process of implementation of the agreement is undertaken. This article examines the provisions of the Straddling Stocks Agreement, as well as some of the underlying pressures and difficulties that may threaten their successful implementation and undermine the effectiveness of international regimes for the management of marine living resources.

Grassland Enclosures: Catalyst of Land Degradation in Inner Mongolia

Since decollectivization, Chinese government policies have promoted household enclosures as the best solution to maximize pastoral productivity and control desert expansion in grassland areas. Recent fieldwork from Inner Mongolia contradicts this optimism. Data and participant-observation reveal that enclosures, as implemented through village level social context, actually compound grazing problems for most residents and the wider ecosystem. Expanding household enclosures function to intensify hyper-critical stocking ratios on highly vulnerable rangeland, exacerbating wind and soil erosion processes across vast territories only to protect small isolated fields dedicated to poorly financed fodder cultivation. This case study indicates that privatization of land in modernizing pastoral societies can be less meaningful for good resource management than other factors, such as secure tenure, equitable access to community resources, and meaningful institutional supports in the form of credit, production service...

Restorying family therapy

This article describes a multi-systemic model of therapy developed by the author over the past decade and summarizes the main products of this project: Explication of key family systems notions, strategic family play therapy, multi-systemic therapy, and culturally-competent family therapy. The model incorporates beyond the family system, culture, wider ecosystems, psychodynamics, and the individual's neuropsychological, cognitive, and socio-emotional development. The model enables the therapist to design flexible multimodal interventions.

The Ramsar Convention Comes of Age

The second of February 1992 marked the 21 st anniversary of the adoption of the 1971 Convention on Wetlands of International Importance, especially as Waterfowl Habitat, commonly known as the Ramsar Convention after the town in Iran where it was concluded. For those more familiar with modern concepts of majority, 21 December 1993 constituted the 18th anniversary of its entry into force. The period between these two dates witnessed a significant endeavour by the international community, through the signature at the Rio Earth Summit of the 1992 Convention on Biological Diversity, to establish a basic conceptual framework to underpin the various conservation initiatives embodied in the now substantial number of international treaties for the protection of wildlife. This framework, which was arguably already emerging in customary international law, emphasises a broad, threefold obligation regarding the conservation of ecosystems, of species and of genetic diversity within species. As each species, and indeed each individual member of that species, exists not in isolation but as a functioning unit within a wider ecosystem, it is axiomatic that the protection of natural habitats must continue to play a particularly crucial role in the global conservation effort.

How to achieve high quality research on aquaculture in developing countries

Small pelagic fish, including anchovies, sardines and sardinellas, mackerels, capelin, hilsa, sprats and herrings, are distributed widely, from the tropics to the far north Atlantic Ocean and to the southern oceans off Chile and South Africa. They are most abundant in the highly productive major eastern boundary upwelling systems and are characterised by significant natural variations in biomass. Overall, small pelagic fisheries represent about one third of global fish landings although a large proportion of the catch is processed into animal feeds. Nonetheless, in some developing countries in addition to their economic value, small pelagic fisheries also make an important contribution to human diets and the food security of many low-income households. Such is the case for many communities in the Zanzibar Archipelago and on mainland Tanzania in the Western Indian Ocean. Of great concern in this region, as elsewhere, is the potential impact of climate change on marine and coastal ecosystems in general, and on small pelagic fisheries in particular. This paper describes data and information available on Tanzania's small pelagic fisheries, including catch and effort, management protocols and socio-economic significance. Then, incorporating the rapidly improving understanding of the region's oceanography resulting from the application of remote sensing and oceanographic modelling, the paper undertakes the most complete assessment to date of the potential impacts of climate change on the small pelagic fishery of the Pemba Channel. Pathways of climate change impact are explored and crucial knowledge gaps, both in terms of the fishery itself and the wider ecosystem, are identified in order to guide future research activities. Although we analyse small pelagics in the specific context of the Pemba Channel, the key challenges identified in the analysis are likely to be relevant to many small pelagic fisheries in coastal nations heavily dependent on living marine resources.