Woody species composition, diversity, and ecosystem services of yards along an urban socioeconomic gradient

Woody plants offer a wide range of valuable ecosystem services, but their distribution across socioeconomic gradients in urban landscapes remains poorly understood. Thus, we explored the effect of socioeconomic and legacy factors on plant species richness and phylogenetic diversity, and the motivations for growing and keeping certain species. We sampled a total of 300 households across a socioeconomic gradient in the city of Harare, Zimbabwe, in high-, medium- and low-density areas, representing low to high wealth strata. Trees were mostly grown for ornamental purpose in the rich (low-density) suburbs and utilitarian purposes in the poorer medium to high-density areas. However, trees were also grown with similar proportion for shade across the socioeconomic gradient. Proportion of medicinal and fruit trees increased with household density, while wind break trees were more common in low-density suburbs. Exotic species exhibited greater species richness compared with indigenous species, with both combined and separate assessments of indigenous and exotic species richness revealing a significant positive association with socioeconomic and legacy factors. The composition of species displayed considerable variation along the socioeconomic gradient. Notably, in low-density environments, exotic species maintained elevated phylogenetic diversity in comparison to indigenous species. This distinction was particularly pronounced when analysed independently, revealing a significant positive correlation between exotic species richness and both property value and education level. Our study shows that residents filter specific plant species based on their socioeconomic status and that, relative to low-income households, the rich homeowners have unintentionally incorporated enough exotic species to produce novel phylogenetic diversity of woody plants in their yards. Thus, we confirm the existence of a socioeconomic gradient in terms of species richness, composition, and phylogenetic diversity. However, the imbalance in species richness and phylogenetic diversity across the socioeconomic gradient can be reduced by increased tree planting in open areas, including along streets in medium to high-density areas to improve ecosystem services.

Mapping the Research Landscape on Poaching: A Decadal Systematic Review

Poaching is a widespread activity that affects wildlife management goals and undermines conservation efforts worldwide. Despite its complexity, poaching is still commonly addressed by researchers as a one-dimensional phenomenon. To deepen the scientific understanding of poaching, we conducted a systematic literature review in the Web of Science and Scopus databases for the last 10 years, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses methodology. We found that most studies were carried out in Africa, although 43% of all articles on poaching were published by researchers from the United States and the United Kingdom. The most studied species are elephants (22%), rhinos (19%), wolves (9%), and bears (6%). Although this study identified a wide range of motives and drivers behind poaching activities, more than half of the analyzed articles do not attempt to provide a deeper understanding of this phenomenon. Its understanding of poaching usually does not go beyond the environmental impact of illegal hunting. Our study’s potential limitations may relate to the focus on exclusively English-language articles and, among them, only those discussing mammal, bird, and reptile species. Our findings indicate that global scientific knowledge on poaching in the last 10 years is biased. There is an imbalance between the developed countries that mostly produce knowledge on poaching (usually from Northern America and Europe) and the developing countries commonly an object of interest. This bias is potentially challenging, as the global scientific knowledge on poaching comes from limited experience based on charismatic species and selective case studies. To overcome this gap and develop a deeper understanding of poaching, the scientific community needs to overcome this bias and address illegal hunting wherever it affects the environment and undermines conservation efforts.

Diversity and abundance of macro-invertebrates on abandoned cattle kraals in a semi-arid savanna

Abandoned cattle (Bos taurus) kraals are sources of habitat heterogeneity in dystrophic semi-arid African savannas with a strong positive effect on soil nutrients and plant productivity. However, little is known regarding how macro-invertebrate assemblages vary between abandoned kraals and the surrounding savanna matrix. We tested whether herbaceous biomass and basal and aerial covers and soil nutrients have an effect on aboveground and belowground macro-invertebrate assemblages. Twelve abandoned kraals were contrasted with their paired control plots for soil characteristics, herbaceous productivity, and macro-invertebrate assemblages in Save Valley Conservancy, Zimbabwe. Abandoned kraals had significantly higher concentrations of soil nitrogen (N), phosphorus (P), potassium (K), and calcium (Ca) as well as herbaceous biomass and basal and aerial covers than control plots. Both aboveground and belowground macro-invertebrate species richness were higher on abandoned kraals. However, only belowground macro-invertebrate diversity (Shannon H' and Hill number 1) was significantly higher on abandoned kraals. Soil nutrients and herbaceous productivity had positive and significant correlations with the dominant taxa (Coleoptera, Hymenoptera, Hemiptera, Isoptera, and Myriapoda) on abandoned kraals. These results add to the growing body of evidence that abandoned kraals exert significant effects on savanna spatial heterogeneity years later, with implications on ecosystem processes and functioning.