Landscape and local habitat traits moderate wild bee communities. However, whether landscape effects differ between local habitat types is largely unknown.
Objectives
We explored the way that wild bee communities in three distinct habitats are shaped by landscape composition and the availability of flowering plants by evaluating divergences in response patterns between habitats.
Methods
In a large-scale monitoring project across 20 research areas, wild bee data were collected on three habitats: near-natural grassland, established flower plantings and residual habitats (e.g. field margins). Additionally, landscape composition was mapped around the research areas.
Results
Our monitoring produced a dataset of 27,650 bees belonging to 324 species. Bee communities on all three habitats reacted similarly to local flower availability. Intensively managed grassland in the surrounding landscape had an overall negative effect on the studied habitats. Other landscape variables produced diverging response patterns that were particularly pronounced during early and late season. Bee communities in near-natural grassland showed a strong positive response to ruderal areas. Flower plantings and residual habitats such as field margins showed a pronounced positive response to extensively managed grassland and woodland edges. Response patterns regarding bee abundance were consistent with those found for species richness.
Conclusion
We advise the consideration of local habitat type and seasonality when assessing the effect of landscape context on bee communities. A reduction in the intensity of grassland management enhances bee diversity in a broad range of habitats. Moreover, wild bee communities are promoted by habitat types such as ruderal areas or woodland edges.
Species diversity is declining more rapidly in freshwater ecosystems than in any other, but the consequences for genetic diversity, and hence evolutionary potential, are poorly understood. In part this reflects limited use and development of modern molecular tools and genetic approaches to address conservation questions in rivers, lakes and wetlands. As widespread, diverse and functionally important organisms, freshwater macroinvertebrates are ideal candidates for genetic approaches to reveal, for example, the conservation consequences of demographic histories and past disturbances. However, the availability of microsatellite markers for this group is very limited.
Using next generation sequencing, microsatellite markers were developed for Isoperla grammatica (Poda, 1761), Amphinemura sulcicollis (Stephens, 1836) and Baetis rhodani (Pictet, 1843) to enable conservation genetic investigations of these widespread invertebrate species. Fifty‐two robust microsatellite loci were developed (18, 21 and 13 per species), all with high levels of allelic diversity (7–27, 3–16, 5–13 alleles per loci, respectively).
These tools will allow assessment of genetic structure, dispersal and demographic resilience in these model species as a function of environmental change and variation, thereby aiding freshwater monitoring and conservation. The authors urge further capacity building to support genetic applications to the conservation biology of other aquatic organisms.
Urban and peri-urban agriculture (UPA) significantly contributes to food and nutritional security of urban dwellers in many
African countries. Economic and demographic pressures often lead to transformation of subsistence-oriented traditional homegardens
into commercial production units. Such transformation is claimed to result in decreasing plant diversity, particularly of
local species. A study was therefore undertaken in 51 gardens of Niamey, Niger, to assess the factors determining plant diversity
and the suitability of UPA for in situ conservation of plant genetic resources. In each garden, the number and abundance of
all human-used plant species were determined, and species density, Shannon index and Shannon evenness were calculated. In
the 51 surveyed gardens, a total of 116 plant species were cultivated, most of them for the production of fruits or vegetables.
Annual vegetables dominated, particularly exotic species grown for sale. In the cold season, an average of 14 species were
cultivated per garden, the Shannon index was 0.96 and evenness was 0.39. Commercial gardens had a species richness similar
to that of subsistence gardens, but a lower evenness (P < 0.005), caused by the dominance of a few vegetable species. Gardens of immigrants had a lower Shannon index than those
of members of the local Djerma ethnic group. Stepwise multiple regression analysis showed significant influence of various
variables on plant species richness and diversity parameters: garden size (richness and Shannon index), ethnicity of the gardener
(richness and evenness), gender of the gardener and cash-oriented production (evenness), household size (richness) and garden
possession status (Shannon index). Cluster analysis revealed the existence of five garden types. The highest species richness
and diversity, particularly of perennial and local species, was found in large, peri-urban, commercial gardens managed by
relatively wealthy, elderly gardeners with large families and a regular non-agricultural income. 相似文献
Vasovagal tonus index (VVTI) is an indirect measure of heart rate variability and may serve as a marker of disease severity. Higher heart rate variability has predicted lower tumour burden and improved survival in humans with various tumour types. The purpose of this pilot study was to evaluate VVTI as a biomarker of remission status in canine lymphoma. The primary hypothesis was that VVTI would be increased in dogs in remission compared to dogs out of remission. Twenty-seven dogs were prospectively enrolled if they had a diagnosis of intermediate to high-grade lymphoma and underwent multidrug chemotherapy. Serial electrocardiogram data were collected under standard conditions and relationships between VVTI, remission status and other clinical variables were evaluated. VVTI from dogs in remission (partial or complete) did not differ from dogs with fulminant lymphoma (naive or at time of relapse). Dogs in partial remission had higher VVTI than dogs in complete remission (p = 0.021). Higher baseline VVTI was associated with higher subsequent scores (p < 0.001). VVTI also correlated with anxiety level (p = 0.03). Based on this pilot study, VVTI did not hold any obvious promise as a useful clinical biomarker of remission status. Further investigation may better elucidate the clinical and prognostic utility of VVTI in dogs with lymphoma. 相似文献