A Household Perspective for Biodiversity Conservation

Abstract: Many researchers have implicated human population density in species endangerment, but these correlative studies do not demonstrate causality. We propose that hypotheses implicating human population density in wildlife endangerment at global and national scales owe their public and academic currency as thoroughly to inductive reasoning and repetition as to scientific experimentation. It follows that alternative research hypotheses generated from the same facts should provide equally tenable results. Household density provides such an alternative hypothesis and is growing faster than human population density. We used linear multiple regression models to demonstrate that household density provides a viable alternative statistical hypothesis to human population density for explaining species endangerment (household model, r² = 0.85; population model, r² = 0.84). We then suggest adopting a household perspective for biodiversity conservation because 1) social norms and practices render a household approach to conservation more pragmatic than a human population perspective and 2) shifting the focus toward households could facilitate movement from a human-versus-nature ethic to a humans-situated-within-nature ethic (e.g., a land ethic). Wildlife managers and researchers concerned about the negative influence humans have on biodiversity should consider grounding research, theory, and policy decisions in the dynamics of human households as an alternative to human population.     

Small changes in timing of breeding among subarctic passerines over a 32‐year period

Many bird populations in temperate regions have advanced their timing of breeding in response to a warming climate in recent decades. However, long‐term trends in temperature differ geographically and between seasons, and so do responses of local breeding populations. Data on breeding bird phenology from subarctic and arctic passerine populations are scarce, and relatively little data has been recorded in open‐nesting species. We investigated the timing of breeding and its relationship to spring temperature of 14 mainly open‐nesting passerine species in subarctic Swedish Lapland over a period of 32 years (1984–2015). We estimated timing of breeding from the progress of post‐juvenile moult in mist‐netted birds, a new method exploring the fact that the progress of post‐juvenile moult correlates with age. Although there was a numerical tendency for earlier breeding in most species (on average ?0.09 days/year), changes were statistically significant in only three species (by ?0.16 to ?0.23 days/year). These figures are relatively low compared with what has been found in other long‐term studies but are similar to a few other studies in subarctic areas. Generally, annual hatching dates were negatively correlated with mean temperature in May. This correlation was stronger in long‐distance than in short‐distance migrants. Although annual temperatures at high northern latitudes have increased over recent decades, there was no long‐term increase in mean temperature in May over the study period at this subarctic site. This is probably the main reason why there were only small long‐term changes in hatching dates.     

Overfishing of top predators eroded the resilience of the Black Sea system regardless of the climate and anthropogenic conditions

It is well known that human activities, such as harvesting, have had major direct effects on marine ecosystems. However, it is far less acknowledged that human activities in the surroundings might have important effects on marine systems. There is growing evidence suggesting that major reorganization (i.e., a regime shift) is a common feature in the temporal evolution of a marine system. Here we show, and quantify, the interaction of human activities (nutrient upload) with a favourable climate (run‐off) and its contribution to the eutrophication of the Black Sea in the 1980s. Based on virtual analysis of the bottom‐up (eutrophication) vs. top‐down (trophic cascades) effects, we found that an earlier onset of eutrophication could have counteracted the restructuring of the trophic regulation at the base of the food web that resulted from the depletion of top predators in the 1970s. These enhanced bottom‐up effects would, however, not propagate upwards in the food web beyond the zooplankton level. Our simulations identified the removal of apex predators as a key element in terms of loss of resilience that inevitably leads to a reorganization. Once the food web has been truncated, the type and magnitude of interventions on the group replacing the apex predator as the new upper trophic level have no effect in preventing the trophic cascade. By characterizing the tipping point at which increased bottom‐up forcing exactly counteracts the top‐down cascading effects, our results emphasize the importance of a comprehensive analysis that take into account all structuring forces at play (including those beyond the marine system) at a given time.     

Incubation and brooding performance of the Antarctic Petrel Thalassoica antarctica at Svarthamaren, Dronning Maud Land

Antarctic Petrel Thalassoica antarctica incubation and brooding effort was studied at Svarthamaren, Dronning Maud Land, during the austral summer of 1991–1992. The females probably left the nest site shortly after egg laying. The duration of incubation and brooding shifts as well as the daily weight loss (absolute and proportionate) were comparable with those of other similar-sized procellariform species. Males spent more time incubating and brooding than did females, suggesting higher female energy stress due to egg laying. Incubating birds which were below average weight were likely to desert the nests before their mates returned from feeding trips. Both males and females lost approximately one-fifth of their body-weight during their first incubation shifts. Nevertheless, they increased their initial weights from egg laying to hatching and had their highest initial weights when they returned to start the shift during which the egg hatched. No factors related to adult body-weight explained the duration of the incubation shifts. Both males and females gained weight at a higher rate when at sea than they lost it during incubation, and it is suggested that factors unrelated to food availability or individual feeding skills may be important in regulating the duration of the incubation shifts and the stay at sea.     

Two invasive populations of the dry rot fungus Serpula lacrymans show divergent population genetic structures

The dry rot fungus Serpula lacrymans is a devastating basidiomycete occurring in wooden constructions in temperate regions worldwide. In this study, we compare the genetic structures of two invasive populations from Europe and Japan. Microsatellite data from 14 loci and DNA sequences from four loci demonstrated that the two populations were highly differentiated. Significant isolation by distance effect was observed in Europe and Japan. Higher genetic variation was observed within the Japanese population than within the European population, corresponding with the observed higher richness of vegetative compatibility types in Japan, indicating that there has been a higher level of gene flow from the Asian source populations to Japan than to Europe. The European population is genetically more homogenous with only six detected vegetative compatibility types. Various tests indicate that both the European and the Japanese populations have gone through population bottlenecks prior to population expansion. No identical multi‐locus genotypes were observed within Japan and very few within Europe, indicating limited clonal dispersal. Deviations from Hardy Weinberg expectations were observed both in Europe and Japan and heterozygote excess were observed at several loci, especially in Europe. Possible explanations for this pattern are discussed.     

Reconciling Wildlife Management's Conflicted Purpose With a Land Community Worldview

ABSTRACT To reach its potential wildlife management needs a coherent purpose. Traditional divisions between science, society, and nature, however, create conflicts between responsibility to science, the public, and nature. These divisions emerged as early as Plato's (400 BC) allegory of the cave. In Plato's allegory human society existed inside a cave formed by its own delusions, and a philosopher or scientist could leave the cave and apprehend reality in nature. Wildlife management's simultaneous responsibility to public preferences, objective truth, and biotic integrity provides the foundation for a conservation worldview capable of transcending the divisions embodied in Plato's allegory. In this paper we deconstruct the conflicted worldview standing on that foundation and describe a land community-based worldview for wildlife management that could replace it. The transition from traditional views of science, society, and nature to a land community worldview requires 1) changing scientific stewardship from seeking objective truth to seeking credible truth, 2) changing political stewardship from following societal dictates to representing wildlife within the land community, and 3) changing ethical stewardship from protecting biotic integrity to fighting permanent closure of land community boundaries. Adopting a land community worldview for wildlife management requires relinquishing the illusion of absolute objectivity and a fall from status as neutral arbiters of knowledge but provides a means for honorably seeking reliable knowledge, serving the public and respecting the land community.