The world's biodiversity is in peril. The major threats to biodiversity globally are habitat change, overexploitation, climate change, invasive species and pollution. Not only do these stressors impact free-living organisms, but they affect parasitic ones as well. Herein, this perspective examines the potential consequences of these anthropogenic perturbations on helminth populations and communities, with emphasis on significant developments over the past decade. Furthermore, several case studies are examined in more detail for each of these threats to biodiversity. While effects are widespread and diverse, for the most part all these environmental stressors have negative effects on parasite populations and communities. Those parasites with complex life cycles that are trophically transmitted are often more at risk, although larval parasites with a wide host spectrum, and directly transmitted ectoparasites, appear less threatened and may even benefit. However, differential effects on hosts and parasites, on parasite life cycle stages and on host–parasite interactions made specific predictions difficult and context-dependent. Experimental laboratory and mesocosm studies on specific parasites that test effects on the different life cycle stages, hosts and host–parasite interactions, permitting the determination of net effects of an environmental stressor, yield insightful and sometimes counterintuitive results, although they remain a simplification of real-world complexity. Recent advances in the use of parasites as bioindicators of effects also are discussed.

In countries with emerging and developing economies the need to promote development and the lack of information on the status of the Near Threatened Eurasian otter Lutra lutra have given rise for concern about the conservation status of the species. In Albania information about the distribution of this otter dates from 1985. In 2013 we resurveyed 31 sites previously surveyed in 1985, and a further 42 sites throughout the country. At each site nine habitat variables of potential importance to otters were recorded and analysed. Overall the distribution pattern in 2013 did not differ from that recorded in 1985, although a reduction in marking intensity suggested a possible decline in otter numbers. Distribution of the otter has been influenced by land use and human density, suggesting man-induced habitat changes since the fall of communism may have affected the quality and fragmentation of otter habitats.

Wildlife populations on Amami Island, Japan, have been affected by forest clear-felling and the introduction of alien species, in particular the mongoose Herpestes auropunctatus. We used monitoring data collected over 24 years to track changes in the population sizes of five species of mammals and 20 species of birds. We assigned species to the following groups: indigenous, rare, insectivorous, negatively affected by forest clear-cutting, and negatively affected by mongoose invasion. We examined trends in each group at four time points between 1985 and 2010 using two methods: species abundance estimates and the Living Planet Index. We then assessed the usefulness of these methods as tools for conservation planning. Inspecting species individually we identified four main patterns of abundance change: (a) an increase from the first to the last census period, (b) an increase in all periods except 2009–2010, (c) a decrease from 1985–1986 to 2001–2002 but an increase in 2009–2010, and (d) a decrease in all census periods. We observed certain relationships between these patterns and the species groups assigned as above. According to the Living Planet Index the group negatively affected by forest clear-cutting did not show significant recovery and the groups of rare species and species negatively affected by mongoose recovered to c. 40% of the original level after a sharp decline during 1985–2002. The Living Planet Index is a more useful tool for assessing the urgency of particular conservation needs, although limited information on species abundance reduces its representativeness for some groups.

The ‘aggregation model of coexistence’ predicts that a strong and independent aggregation of species across ephemeral resource patches promotes species coexistence and maintains diversity. This study examines the role of aggregation in maintaining tropical dung beetle diversity and the effects of deforestation on aggregation patterns and diversity loss. Using clusters of pitfall traps, dung beetle aggregation was quantified in natural and disturbed habitat at nested temporal and spatial scales in central Peru. The results indicate that dung was colonized by a greater number of species, many of which were large, leading to a higher total beetle biomass in forest habitat than in deforested, farm habitat. Beetles were intraspecifically aggregated at each spatial scale examined. Habitat-type (forest/deforested) had no effect on the intensity of intra- or interspecific aggregation. Analyses of aggregation patterns revealed that dung beetle assemblages in forest habitat were generally saturated whereas in deforested habitat they were unsaturated. In general, interspecific aggregation was too weak relative to intraspecific aggregation to explain the high diversity of species in forest habitat. Other mechanisms, including resource partitioning are likely to play a greater role in maintaining the diversity of dung beetle assemblages in the region. These results also indicate that the loss of species from disturbed habitat has not been due to a breakdown in the aggregation mechanism.

The Ethiopian bush crow Zavattariornis stresemanni is one of the most remarkable ornithological discoveries of the 20th century. It is restricted to an area of c. 5,000 km2 in southern Ethiopia, and a large part of its range is protected inside Yabello Wildlife Sanctuary. We report on the results of roadside counts carried out in 1989, 1995 and 2003 showing that the population of the species has decreased by 80% during this time. By comparing two Landsat satellite images from 1986 and 2002, we highlight land cover trends within the range of the species. These include a general increase in bush density, probably related to increasing grazing pressure by domestic animals, fire suppression (only in the Sanctuary) and the disappearance of wild herbivores. Land cover trends differed between the Sanctuary and the area outside, where open areas expanded, apparently indicating an increase in agricultural exploitation. Satellite images also showed that, within its range, the bush crow selects areas having relatively open terrain. Our data suggest that the population decrease within the Sanctuary could be due to the encroachment of open savannah by dense bush and that, therefore, the Sanctuary has failed to protect the bush crow. More research is urgently needed to evaluate its conservation status outside the Sanctuary and the impact of human activities on the species.