John Agard

Science for managing ecosystem services: Beyond the Millennium Ecosystem Assessment

The Millennium Ecosystem Assessment (MA) introduced a new framework for analyzing social–ecological systems that has had wide influence in the policy and scientific communities. Studies after the MA are taking up new challenges in the basic science needed to assess, project, and manage flows of ecosystem services and effects on human well-being. Yet, our ability to draw general conclusions remains limited by focus on discipline-bound sectors of the full social–ecological system. At the same time, some polices and practices intended to improve ecosystem services and human well-being are based on untested assumptions and sparse information. The people who are affected and those who provide resources are increasingly asking for evidence that interventions improve ecosystem services and human well-being. New research is needed that considers the full ensemble of processes and feedbacks, for a range of biophysical and social systems, to better understand and manage the dynamics of the relationship between humans and the ecosystems on which they rely. Such research will expand the capacity to address fundamental questions about complex social–ecological systems while evaluating assumptions of policies and practices intended to advance human well-being through improved ecosystem services.

Trade-offs across Space, Time, and Ecosystem Services

Ecosystem service (ES) trade-offs arise from management choices made by humans, which can change the type, magnitude, and relative mix of services provided by ecosystems. Trade-offs occur when the provision of one ES is reduced as a consequence of increased use of another ES. In some cases, a trade-off may be an explicit choice; but in others, trade-offs arise without premeditation or even awareness that they are taking place. Trade-offs in ES can be classified along three axes: spatial scale, temporal scale, and reversibility. Spatial scale refers to whether the effects of the trade-off are felt locally or at a distant location. Temporal scale refers to whether the effects take place relatively rapidly or slowly. Reversibility expresses the likelihood that the perturbed ES may return to its original state if the perturbation ceases. Across all four Millennium Ecosystem Assessment scenarios and selected case study examples, trade-off decisions show a preference for provisioning, regulating, or cultural services (in that order). Supporting services are more likely to be “taken for granted.” Cultural ES are almost entirely unquantified in scenario modeling; therefore, the calculated model results do not fully capture losses of these services that occur in the scenarios. The quantitative scenario models primarily capture the services that are perceived by society as more important—provisioning and regulating ecosystem services—and thus do not fully capture tradeoffs of cultural and supporting services. Successful management policies will be those that incorporate lessons learned from prior decisions into future management actions. Managers should complement their actions with monitoring programs that, in addition to monitoring the short-term provisions of services, also monitor the long-term evolution of slowly changing variables. Policies can then be developed to take into account ES trade-offs at multiple spatial and temporal scales. Successful strategies will recognize the inherent complexities of ecosystem management and will work to develop policies that minimize the effects of ES trade-offs.

Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in harbor sediments from Sea Lots, Port-of-Spain, Trinidad and Tobago

Concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were determined in nearshore marine surficial sediments from three locations in Trinidad. Sediments were sampled at Sea Lots on the west coast, in south Port-of-Spain Harbor, south of Sea Lots at Caroni Lagoon National Park, and on Trinidads east coast at Manzanilla. Total PCB concentrations in Sea Lots sediments ranged from 62 to 601ng/g (dry weight {dw}), which was higher than at Caroni and Manzanilla, 13 and 8ng/g dw, respectively. Total OCP concentrations at Sea Lots were ranged from 44.5 to 145ng/g dw, compared with 13.1 and 23.8n/g (dw), for Caroni and Manzanilla respectively. The concentrations of PCBs and of some OCPs in sediments from Sea Lots were above the Canadian interim sediment quality guidelines. To date, this data is the first report on the levels of PCBs and other organochlorine compounds from Trinidad and Tobago.

Biodiversity and ecosystem services require IPBES to take novel approach to scenarios

What does the future hold for the world’s ecosystems and benefits that people obtain from them? While the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) has identified the development of scenarios as a key to helping decision makers identify potential impacts of different policy options, it currently lacks a long-term scenario strategy. IPBES will decide how it will approach scenarios at its plenary meeting on 22–28 February 2016, in Kuala Lumpur. IPBES now needs to decide whether it should create new scenarios that better explore ecosystem services and biodiversity dynamics. For IPBES to capture the social-ecological dynamics of biodiversity and ecosystem services, it is essential to engage with the great diversity of local contexts, while also including the global tele-coupling among local places. We present and compare three alternative scenario strategies that IPBES could use and then suggest a bottom-up, cross-scale scenario strategy to improve the policy relevance of future IPBES assessments. We propose five concrete steps as part of an effective, long term scenario development process for IPBES in cooperation with the scientific community.

A four-dimensional response surface analysis of the ontogeny of physiological adaptation to salinity and temperature in larvae of the palaemonid shrimp Macrobrachium rosenbergii (de Man)

Abstract Macrobrachium rosenbergii (de Man) is an important commercial species whose larvae develop through several stages in brackish water, after which they metamorphose and the postlarvae migrate into fresh water. Modelling the multiple factor interactions which may affect the ontogeny of physiological adaptation during larval development provides an opportunity to evaluate Alderdices concept (Alderdice, D.F., 1972. Factor combinations: responses of marine poikilotherms to environmental factors acting in concert. In: Kinne, O. (Ed.), Marine Ecology, vol. 1, part 3, Environmental Factors. Wiley-Interscience, London, pp. 1659–1722) that the integral mobility of continuously unfolding fluid salinity–temperature–time response surfaces can identify important underlying adaptive phases in the life of an animal. Weight-specific oxygen consumption and nitrogen excretion were measured in up to seventeen larval stages of Macrobrachium rosenbergii , reared in 12 combinations of salinity (10.1–17.1‰) and temperature (24–33°C). Changes in larval weights, respiration, excretion, net growth efficiencies ( K 2 ) and O:N ratios were modeled by polynomial regression and examination of the unfolding of the phases in the resulting nonlinear three dimensional response surfaces along the fourth or time/larval stage dimension. Larval growth rate was sigmoid and divided into three phases each comprising several instars: a post embryonic low or no-growth phase, an exponential-growth phase and a pre-metamorphosis slow growth phase. Low K 2 and O:N values during the low or no-growth phase indicate that growth is not the priority and available energy from stored lipoprotein may be channeled into programmed tissue reorganization. Histology suggests that the focus is dedifferentiation and reconstruction of the hepatopancreas. A sharp discontinuity, followed by a rotation and translation of the oxygen consumption response surface at this point suggests a physiological shift to a new domain of attraction. This was related to the commissioning of the hepatopancreas and the changeover to reliance on an exogenous food supply. In the exponential growth phase increasing net growth efficiency and low O:N values show that anabolic processes predominate. During the final pre-metamorphosis phase, net growth efficiency decreases but energy utilization remains high. The weight specific ammonia-nitrogen excretion response surface shows a tendency towards increasing excretion as salinity decreases. This suggests that the new physiological attractor is the development of an osmoregulatory mechanism based on counter-ion exchange. This may be a driving force for postlarval migration back to freshwater. This study suggests that the integral mobility of response surfaces during larval development can identify homeostatic adjustments associated with crossing the apparent boundary between one physiological domain of attraction and another.

Application of toxicity identification evaluation procedures for characterizing produced water using the tropical mysid, Metamysidopsis insularis

Toxicity identification evaluations (TIEs) were performed on seven produced water (PW) effluents from inland discharge facilities operated in Trinidad and Tobago, a Caribbean tropical country with one of the oldest commercial oil industries in the world. The research was performed to determine the presence and magnitude of toxicity and characterize which toxicants are responsible for observed effects. Marine effluent toxicity characterizations with Metamysidopsis insularis revealed high whole acute toxic-unit response for produced water ranged from 8.1 to > 17.0 acute toxic-unit (initial toxicity test) and 5.7 to 1,111 acute toxic-unit (baseline toxicity test). Toxicity test results for all sites except one, which had the highest toxicity, are comparative with similar studies on produced water. The toxicological causality of this complex mixture differed for each PW with nonpolar organics being consistently toxic in all samples. Other potential toxicants contributing to overall toxicity to a much lesser extent were metals, ammonia, and volatile organic compounds. With the use of sodium thiosulfate and filtration manipulations for only PW6 sample, there was very slight reduction in toxicity; therefore, oxidants and filterable materials were not a great contributing factor. Whole effluent toxicity also can be attributed to ionic imbalance and the very stable oil-in-water emulsion that consists of fine oil droplets (less than 0.1-10 microm with an average diameter of 2.5 microm). This investigation is the first of its type in Trinidad and demonstrates clearly the applicability of this test method and local test species for evaluating complex effluents in tropical environments.

The relation between productivity, disturbance and the biodiversity of Caribbean phytoplankton: applicability of Huston's dynamic equilibrium model

Abstract This study tests the predictions of Hustons dynamic equilibrium model of species richness. It examines field data showing the effects of silicates/disturbance and productivity on the number of coexisting species within a functional type (diatoms) in a community. Using multivariate statistical techniques, the pattern of phytoplankton species richness throughout the Caribbean islands is modelled in relation to overlapping gradients of silicates/disturbance and primary productivity originating from the Amazon and Orinoco rivers. Data were obtained from 44 Caribbean, South and Central American oceanographic stations sampled during the Caribbean Oceanographic Resources Exploration (CORE) of 1990. The results of the study give support to Hustons dynamic equilibrium hypothesis, which predicts maximum species richness under conditions of intermediate productivity and disturbance. Fishery statistics for the region show that the diversity of harvested marine species of commercial importance is a mirror of the diversity of the phytoplankton. Some consequences of global environmental change to the dynamic equilibrium of the allocation of fishery resources between small Caribbean states are discussed.

Metals in sediments and fish from Sea Lots and Point Lisas Harbors, Trinidad and Tobago.

Concentrations of heavy metals were determined in nearshore marine sediments and fish tissue from Sea Lots area on the west coast, at Caroni Lagoon National Park, and in the Point Lisas harbor, Trinidad. The most dominant metals found in sediments were Al, Fe and Zn with mean concentrations highest at Sea Lots (Al-39420 μg/g; Fe-45640 μg/g; Zn-245 μg/g), when compared to sediments from Point Lisas (Al-11936 μg/g; Fe-30171 μg/g; Zn-69 μg/g) and Caroni (Al-0400 μg/g; Fe-19000 μg/g; Zn-32 μg/g), High concentration of Cu, Al, Fe and Zn were also detected in fish tissue from Point Lisas and Caroni. Metal concentrations in fish tissue showed significant correlation with sediment metals concentration, which suggests that tissue levels are influenced by sediment concentration. Of the metals, only Zn, Hg and Cu had a bioaccumulation factor (BAF) greater than one, which suggests a high bioaccumulation potential for these metals.

Comparative Sensitivity of Three Tropical Cladoceran Species (Diaphanosoma brachyurum, Ceriodaphnia rigaudii and Moinodaphnia macleayi) to Six Chemicals

The toxicities of six chemicals (cadmium chloride, potassium dichromate, sodium dodecyl sulfate, potassium chloride, Tritox X-100 and copper (II) sulphate) was determined for three tropical freshwater cladoceran, Moinodaphnia macleayi, Ceriodaphnia rigaudii and Diaphanosoma brachyurum. The data was subsequently used to compare the relative sensitivity of the three species. Relative sensitivities were determined by comparing the 48-hour LC50 values using an independent t-test and interspecies correlation. Potassium dichromate was the most toxic compound tested, while potassium chloride was the least toxic to all three species. The 48 h LC50 values for D. brachyurum ranged from 0.003 mg/L to 30.4 mg/L; M. macleayi LC50 values ranged from 0.003 mg/L to 30.1 mg/L whereas for C. rigaudii the values ranging between 0.002 mg/L to 21.1 mg/L. The LC50 values for C. rigaudii was significantly less (P < 0.05) than M. macleayi for five of the compounds tested, whereas for D. brachyurum it was significantly (P < 0.05) less than four of the compounds tested. The interspecies correlation also suggested that C. rigaudii and M. macleayi were more similar in sensitivity (R2 = 0.96) to each other than D. brachyurum (R2 = 0.91 with M. macleayi, and R2 = 0.87 with C. rigaudii).

Trade-off between digestion and respiration in two airbreathingcallichthyid catfishes Holposternum littorale (Hancock) and Corydoras aeneus (Gill)

In callichthyid catfishes, the posterior intestine is modified to function as an air breathing organ by being air-filled, thin-walled and highly vascularized. These modifications make it unsuitable for digestive functions and digesta has to be transported quickly through this region to minimize disruption of vital respiratory functions. However, the weak muscles of the wall of the respiratory intestine make this problematic. It is hypothesized that the unidirectional ventilatory air current within the respiratory intestine is responsible for the quick transport of digesta through the respiratory intestine. To verify this, movement of digesta through the alimentary tract was examined in Hoplosternum littorale and Corydoras aeneus that were either allowed to breathe air or prevented from air breathing. When air breathing was prevented, digesta was not transported to the rectum in H. littorale and there was a 94% reduction in the amount of digesta in the rectum of C. aeneus. This study suggests that the anterior digestive intestine facilitates the passage of air although it is filled with digesta. The anterior digestive intestine packages digesta into a string of slightly compressed boluses, creating an air channel in the digestive intestine thus allowing air to pass unimpeded.