Can you be bothered? The role of participant motivation in the valuation of species conservation measures

Group-based approaches to the elicitation of stated preferences are considered particularly suitable for valuing unfamiliar or complex environmental goods. While such exercises provide participants with detailed information and time to think and deliberate, they require a considerable degree of motivation from the respondents. Effects of motivation on willingness to pay (WTP) tend to be ignored within the valuation research community, although similar effects have been reported in psychological literature. In this study, a novel approach using video recordings and behaviour coding of participants in group-based Market Stall meetings was employed to measure motivation as well as its impact on WTP and the theoretical and convergent validity of stated WTP. Indicators of motivation correlated significantly with both WTP statements and their validity, with more motivated individuals stating higher and more valid bids. These findings suggest that the recognition of motivation is an important novel element of research into stated preferences, particularly with respect to usefulness and quality of WTP measures.     

Toward an improved ecosystem based management approach: incorporating catchment characteristics into better management and planning of the Great Barrier Reef marine ecosystem

Discharge from the Great Barrier Reef Catchment (GBRC) is considered the second most serious threat to the Great Barrier Reef, Australia. Utilising principal component analysis (PCA) and cluster analysis (CA), this research aimed to assess the variability and co-variation of 28 water basins (WBs) within the GBRC, in order to improve the institutional arrangements and regulation of water quality and increase collaboration horizontally between management organisations, and vertically between government tiers. Water basin variability was measured by nine variables: size (ha), population, agricultural land use (ha), number of major water storages, major rivers and major towns, total nitrogen exported (T/yr), total phosphorus exported (T/yr) and herbicide use (ha). The Fitzroy WB, with PC scores of 7.0081, 2.2897 and ?1.6504, was identified as the most dissimilar and therefore needing to be managed differently. Many WBs within the same regions were very dissimilar to each other, indicating that current management practices, based largely on geographic location, are unlikely to be the most efficient and effective. Instead, managing groups of WBs with similar geo-political properties (determined by the CA) could be more effective and efficient. Coordination and collaboration are key to successful ecosystem based management, therefore managing similar WBs together through inter-NRM (natural resource management) agreements, irrespective of their geographical location, facilitates management bodies building strong, cooperative working relationships.     

Limited geographic variation in the acoustic structure of and responses to adult male alarm barks of African green monkeys

The global diversity of human languages is a remarkable feature of our species, which requires a capacity for rapid vocal learning. Given that primate alarm calling systems have played an important role in the language origin debate, identifying geographic variation in primate alarm calls and understanding the underlying causal mechanisms are important steps to help uncover evolutionary precursors to language. This study investigates geographic variation in the alarm bark of the widely distributed African green monkey (Chlorocebus). To quantify geographic variation in spectral and temporal call structure, acoustic analysis was used to compare the adult male barks of green monkeys (Chlorocebus sabaeus) and two subspecies of vervet (Chlorocebus pygerythrus pygerythrus and Chlorocebus pygerythrus hilgerti). Playback experiments were also carried out to test whether adult male vervets would distinguish between the barks of own-group males, unknown conspecific males and green monkey males. Acoustic analysis showed that, whilst similar in overall structure, the barks of green monkeys could be distinguished from vervet barks with a high degree of accuracy; the barks of vervet subspecies could also be discriminated, although to a lesser degree. Males responded most strongly to unknown conspecific males’ barks, and exhibited responses typical of leopard-avoidance and territorial defence. Taken together, these findings indicate that variation in alarm calls can be best explained by phylogenetic distance, and that intra- and inter-species differences are relevant during social interactions. Moreover, barks may function as an alarm and display call, which could explain the observed sexual dimorphism in barks in this genus.     

Temperature adaptation in eurythermal cod (Gadus <Emphasis Type="Italic">morhua</Emphasis>): a comparison of mitochondrial enzyme capacities in boreal and Arctic populations

Activities of citrate synthase (CS), cytochrome c oxidase (CCO) and the electron transport system (ETS) were investigated in white muscle and liver of laboratory-maintained cod, Gadus morhua, from the North Sea, Norwegian coast and Barents Sea for an analysis of temperature acclimation and adaptation in aerobic metabolism. Cold acclimation within each population led to elevated activities of CS, CCO and ETS in white muscle. In liver, however, only North Sea cod showed cold-compensated CS activities, with CCO and ETS unchanged. In contrast, cold-acclimated Norwegian cod displayed unchanged enzyme activities, and Arctic cod showed elevated activities for CS, but decreased activities for CCO and no change in ETS. Between-population comparisons revealed clear evidence for permanent cold adaptation in white muscle of northern (Norwegian coast and Barents Sea) compared to boreal (North Sea) cod populations, reflected by higher activities of CS, CCO and ETS at the same acclimation temperature. Cold-compensated, mass-specific enzyme activities in liver were found in northern compared to boreal cod for CS and CCO, however, for ETS, after warm acclimation only. When evaluated as capacity in total liver, such activities were only found in northern populations in the case of CS at all temperatures, and for CCO and ETS at 15°C only. Hepatosomatic index (I_H) and liver lipid contents were highest in North Sea cod, with similar I_H but lower lipid contents in cold- versus warm-acclimated animals. An acclimation effect on I_H was found in Norwegian cod only, with higher I_H but unchanged lipid contents in the cold. In conclusion, permanent cold adaptation of muscle aerobic metabolism prevails in cod populations at higher latitudes, which is in line with permanently elevated rates of oxygen consumption observed in a parallel study. These differences reflect higher maintenance costs in cold-adapted versus cold-acclimated cod.     

Observations on rock boring by Alpheus saxidomus (Crustacea: Alpheidae)

This study describes some aspects of the distribution, ecology, and rock boring behaviour of the shrimp Alpheus saxidomus Holthuis from the Pacific coast of Costa Rica. This species has a typical hammer-shaped dactylus on the first right pereiopod of females and males that shows tracks of abrasion at the hammer-head. Structural analysis of this hammer-dactylus proved that it is suited for the mechanical treatment of rocks. The very thick and calcified cuticle of the hammer is mostly formed by the sclerotinized, hard exocuticle, which has abundant pore canals.