Ethnobotanical Study of Cowpea (Vigna Unguiculata (L.) Walp.) in Senegal

Cowpea (Vigna unguiculata) plays a key role in family farming systems in Senegal. It makes an essential contribution to economic, nutritional and food security. Although it is crucial, little is known about how farmers classify the diversity of local varieties or about the social practices associated with them. The aim of this study is to characterize the farming practices associated with growing cowpea in Senegal. Surveys were conducted involving 335 rural farmers living in 37 villages, spread across seven regions that produce cowpea. An average of ten farmers were randomly selected in each village. The results reveal that cowpea is a key feature of cropping systems in the studied area. Our findings highlight the high diversity of local cowpea varieties with 59 local names inventoried. In 75% of cases, the name refers to the seed’s morphology or color. Cowpea production is more diverse in Diourbel and Louga and less diverse in the south. More than half the farmers (57%) acquired their cowpea seeds (early, semi-early and late varieties) outside their village, either from markets, seed suppliers or NGOs. This new understanding of farmers’ expertise in the management of cowpea and its local variability will help to valorise local diversity in breeding programmes.

Spatial dynamics and vaccine-induced fitness changes of Bordetella pertussis

Competitive interactions between pathogen strains drive infection risk. Vaccines are thought to perturb strain diversity through shifts in immune pressures, however, this has rarely been measured due to inadequate data and analytical tools. Bordetella pertussis (B. pertussis), responsible for 160,000 deaths annually, provides a rare natural experiment as many countries have switched from whole cell vaccines to acellular vaccines, which have very different immunogenic properties. Here we use 3,344 sequences from 23 countries and build phylogenetic models to reveal that B. pertussis has substantial diversity within communities, with the relative fitness of local genotypes changing in response to switches in vaccine policy. We demonstrate that the number of transmission chains circulating within subnational regions is strongly associated with host population size. It takes 5-10 years for individual lineages to be homogeneously distributed throughout Europe or the United States. Increased fitness of pertactin-deficient strains following implementation of acellular vaccines, but reduced fitness otherwise, can explain long-term genotype dynamics. These findings highlight the role of national vaccine policies in shifting local diversity of a pathogen that still poses a large burden on global public health.

Diversity and endemism of the flora of Ethiopia and Eritrea: state of knowledge and future perspectives

Understanding biodiversity of plants depends on detailed knowledge of floristics and environmental parameters. According to the Flora of Ethiopia and Eritrea (FEE; 1989–2009), the latest academic flora of these two topographically complex countries, the number of taxa (including non-indigenous ones) is 6027 of which 647 are endemic. Since 2009, 56 indigenous taxa have been described from the FEE area. Based on FEE data and later information, the number of indigenous species is here counted at 5219. In the RAINBIO database Sosef et al. (BMC Biol 15:1–23, 2017) counted the number of indigenous species in Ethiopia at 4481 (Eritrea not counted). Studies of local diversity and endemism produce different results with varying methods and sources: FEE data show highest diversity in the southern part of Ethiopia near the borders with Kenya, while RAINBIO data show highest diversity in the south-west and around the town of Harar. Wang et al. (J Syst Evol 58(1):33–42, 2020) found the highest ‘weighted endemism’ in the central Ethiopian mountains, while our FEE data indicates highest single-region endemism near the borders with Kenya and Somalia; Hawthorne and Marshall (Gard Bull Singap 71(Suppl. 2):315–333, 2019), weighting species according to rarity, found the highest ‘bioquality score’ in the same areas as our highest single-region endemism. Studies of altitudinal diversity show a ‘mid-elevation diversity bulge’ at 1400–2100 m a.s.l. More data are needed before we understand the complex diversity of the two countries, including altitudinal diversity. We review needs for additional data gathering and modelling that may help answering outstanding questions. Graphic abstract

Species ecology explains the spatial components of genetic diversity in tropical reef fishes

Generating genomic data for 19 tropical reef fish species of the Western Indian Ocean, we investigate how species ecology influences genetic diversity patterns from local to regional scales. We distinguish between the α , β and γ components of genetic diversity, which we subsequently link to six ecological traits. We find that the α and γ components of genetic diversity are strongly correlated so that species with a high total regional genetic diversity display systematically high local diversity. The α and γ diversity components are negatively associated with species abundance recorded using underwater visual surveys and positively associated with body size. Pelagic larval duration is found to be negatively related to genetic β diversity supporting its role as a dispersal trait in marine fishes. Deviation from the neutral theory of molecular evolution motivates further effort to understand the processes shaping genetic diversity and ultimately the diversification of the exceptional diversity of tropical reef fishes.

Influence of landscape homogenization due to river damming on dragonfly (Odonata) community structuring in a subtropical forest in the southern Atlantic Forest

Human activities affect the structure, dynamics, and energy flow of aquatic ecosystems. River damming, a common anthropic impact in Brazil, changes solar incidence, water flow, and temperature of waterbodies, thereby affecting their fauna. Due to their high sensitivity to environmental changes, the Odonata may be indicators of these impacts. We sampled two ecologically distinct sites, (1) a quasi-pristine forested area; and (2) a nearby human-impacted reservoir landscape, to evaluate the effects of damming on odonate community structure. The species composition of quasi-pristine communities was more heterogeneous and differed almost completely (indicating high turnover) from that of the reservoir-area communities. The capacity of the reservoir to maintain local fauna was almost nil. The communities in the changed landscape had the highest local diversity, which is related to the high occurrence of widespread generalist South American species. We also tested two recently proposed bioindication ratio tools based on the abundance of high-level taxonomic categories; both effectively demonstrated the extent of the impacts of damming. The best performing ratios were Coenagrionidae/other Zygoptera richness ratio, Zygoptera/Anisoptera abundance ratio, and Libellulidae/other Anisoptera richness ratio. The reservoir landscape promotes biotic homogenization. However, the water supply system entails the preservation of part of the native habitat in its surrounding areas, consequently maintaining local biodiversity in quasi-pristine environments.

Different temporal trends in vascular plant and bryophyte communities along elevational gradients over four decades of warming

Despite many studies showing biodiversity responses to warming, the generality of such responses across taxonomic groups remains unclear. Very few studies have tested for evidence of bryophyte community responses to warming, even though bryophytes are major contributors to diversity and functioning in many ecosystems. Here we report an empirical study comparing long-term change of bryophyte and vascular plant communities in two sites with contrasting long-term warming trends, using “legacy” botanical records as a baseline for comparison with contemporary resurveys. We hypothesized that ecological changes would be greater in sites with a stronger warming trend, and that vascular plant communities, with narrower climatic niches, would be more sensitive than bryophyte communities to climate warming. For each taxonomic group in each site, we quantified the magnitude of changes in species’ distributions along the elevation gradient, species richness, and community composition. We found contrasted temporal changes in bryophyte vs. vascular plant communities, which only partially supported the warming hypothesis. In the area with a stronger warming trend, we found a significant increase of local diversity and beta-diversity for vascular plants, but not for bryophytes. Presence absence data did not provide sufficient power to detect elevational shifts in species distributions. The patterns observed for bryophytes are in accordance with recent literature showing that local diversity can remain unchanged despite strong changes in composition. Regardless of whether one taxon is systematically more or less sensitive to environmental change than another, our results suggest that vascular plants cannot be used as a surrogate for bryophytes in terms of predicting the nature and magnitude of responses to warming. Thus, to assess overall biodiversity responses to global change, abundance data from different taxonomic groups and different community properties need to be synthesized.

ON/OFF domains shape receptive fields in mouse visual cortex

In higher mammals, thalamic afferents to primary visual cortex (area V1) segregate according to their responses to increases (ON) or decreases (OFF) in luminance1–4. This organization induces columnar, ON/OFF domains postulated to provide a scaffold for the emergence of orientation tuning2,5–15. To further test this idea, we asked whether ON/OFF domains exist in mouse V1 – a species containing orientation tuned, simple cells, like those found in other mammals16–19. Here we show that mouse V1 is indeed parceled into ON/OFF domains. Revealingly, fluctuations in the relative density ON/OFF neurons on the cortical surface mirror fluctuations in the relative density of ON/OFF receptive field centers on the visual field. In each cortical volume examined, the average of simple-cell receptive fields correlates with the difference between the average of ON and OFF receptive fields7. Moreover, the local diversity of simple-cell receptive fields is explained by a model in which neurons linearly combine a small number of ON and OFF signals available in their cortical neighborhoods15,20. Altogether, these findings indicate that ON/OFF domains originate in fluctuations of the spatial density of ON/OFF inputs on the visual field which, in turn, shapes the structure of receptive fields10–13,21–23.