Freshwater mussels are declining globally, and effective conservation requires prioritizing research and actions to identify and mitigate threats impacting mussel species. Conservation priorities vary widely, ranging from preventing imminent extinction to maintaining abundant populations. Here, we develop a portfolio of priority research topics for freshwater mussel conservation assessment. To address these topics, we group research priorities into two categories: intrinsic or extrinsic factors. Intrinsic factors are indicators of organismal or population status, while extrinsic factors encompass environmental variables and threats. An understanding of intrinsic factors is useful in monitoring, and of extrinsic factors are important to understand ongoing and potential impacts on conservation status. This dual approach can guide conservation status assessments prior to the establishment of priority species and implementation of conservation management actions.

From May 2005-2006, selections of river crossing locations and sleeping sites used by a one-male group (BE-Group) of proboscis monkeys (Nasalis larvatus) were investigated along the Menanggul River, tributary of the Kinabatangan River, Sabah, Malaysia. The frequency of river crossings for focal monkeys in the BE-Group was significantly higher at locations with narrow branch-to-bank distances. Branch-to-bank distances were defined as the distances between the longest tree branches extending over the river and the bank of river on each side. This was measured in areas crossed by the monkeys. The focal monkeys used locations with a higher probability of successful river crossings that did not require jumping into the water and swimming across than those that did. The frequency of sleeping site usage by the BE-Group was positively correlated with the frequency of using river crossing locations by the focal monkeys. Previous reports on predation of proboscis monkeys indicate that clouded leopards (Neofelis diardi) and crocodilians (Tomistoma schlegeli and Crocodylus porosus) may be the major terrestrial and aquatic predators of these monkeys. The selection of river crossing locations by proboscis monkeys may be influenced both by the threat of these predators and the location of suitable and protected sleeping sites. Finally, sleeping sites locations that offer arboreal escape routes may protect proboscis monkeys from leopard attack.

The invasive alien crayfish Pacifastacus leniusculus is considered harmful to freshwater pearl mussels Margaritifera laevis and M. togakushiensis. It also often colonises mussel habitats in Japan. In order to test the negative effects of alien crayfish on mussels, we evaluated the predation impact of signal crayfish on freshwater pearl mussels in vitro. We tested the relationship between the survival/injury rates of mussels and crayfish predation with respect to different sizes of mussels (four classes based on shell length: 10, 30, 50 and 70 mm). Crayfish selectively fed on the flesh of the 10-mm size class mussels after breaking their shells. The shell margins of mussels in all size classes were injured by crayfish. Results also showed that crayfish particularly injured the 50-mm size class of mussels. This observation could be attributed to this mussel size being the most suitable shell size (29.56-37.73 mm in carapace length) that the crayfish can effectively hold. This study shows that the presence of invasive crayfish reduces freshwater pearl mussel populations by damaging the shell margins and/or killing the mussels. This negative impact of invasive crayfish not only decreases the mussel population but could also limit mussel recruitment, growth and reproduction.

Although the importance of natural licks for terrestrial mammals is widely acknowledged, we report here for the first time its importance for large terrestrial mammals in a degraded riverine forest in Borneo. Our results clearly demonstrated that various mammals, including bearded pig, sambar deer, and endangered orang‐utans, were using the natural lick, though large arboreal/avian herbivore/omnivore animals were not attracted to the natural lick. In addition, the diversity of mammal species recorded in this study was lower than those recorded in the dry lowland forest. Possible reasons for this difference between the different forest types are discussed.

The relationship between pesticide concentrations in Komatsuna (Brassica rapa var. perviridis) shoots and the extractable concentrations in soils by a sequential soil-extraction method was investigated in 8 pesticides and in 4 soils. Concentrations of many pesticides in Komatsuna shoots showed higher positive correlation with water-extractable than with total-extractable soil concentrations. We also examined the effects of the soil-aging periods (SAPs) between pesticide applications and sowing on pesticide concentrations in Komatsuna shoots. Pesticide concentrations in Komatsuna shoots and soil-water extracts decreased with increasing SAPs. These results imply that estimating the pesticide concentrations in crops based on water-extractable concentrations in soil and setting the appropriate SAPs prevent contamination of crops by pesticide residues in soil. However, the correlation between pesticide concentrations in Komatsuna shoots and water extracts in soils, and the effectiveness of pesticide reduction in Komatsuna shoots by setting long SAPs differed according to the pesticide type. Hence, the applicability of the water-extraction method should be verified for each pesticide.