Potential of Airborne LiDAR Derived Vegetation Structure for the Prediction of Animal Species Richness at Mount Kilimanjaro

The monitoring of species and functional diversity is of increasing relevance for the development of strategies for the conservation and management of biodiversity. Therefore, reliable estimates of the performance of monitoring techniques across taxa become important. Using a unique dataset, this study investigates the potential of airborne LiDAR-derived variables characterizing vegetation structure as predictors for animal species richness at the southern slopes of Mount Kilimanjaro. To disentangle the structural LiDAR information from co-factors related to elevational vegetation zones, LiDAR-based models were compared to the predictive power of elevation models. 17 taxa and 4 feeding guilds were modeled and the standardized study design allowed for a comparison across the assemblages. Results show that most taxa (14) and feeding guilds (3) can be predicted best by elevation with normalized RMSE values but only for three of those taxa and two of those feeding guilds the difference to other models is significant. Generally, modeling performances between different models vary only slightly for each assemblage. For the remaining, structural information at most showed little additional contribution to the performance. In summary, LiDAR observations can be used for animal species prediction. However, the effort and cost of aerial surveys are not always in proportion with the prediction quality, especially when the species distribution follows zonal patterns, and elevation information yields similar results

Monitoring arthropods in a tropical landscape: relative effects of sampling methods and habitat types on trap catches

To discuss the challenge of monitoring multi-species responses of tropical arthropods to disturbance, we considered a large dataset (4 × 105 individuals; 1,682 morphospecies representing 22 focal taxa) based on the work of parataxonomists to examine the effects of anthropogenic disturbance on arthropods at Gamba, Gabon. Replication included three sites in each of four different stages of forest succession and land use after logging, surveyed during a whole year with four sampling methods: pitfall, Malaise, flight-interception and yellow pan traps. We compared the suitability of each sampling method for biological monitoring and evaluated statistically their reliability for 118 arthropod families. Our results suggest that a range of sampling methods yields more diverse material than any single method operated with high replication. Multivariate analyses indicated that morphospecies composition in trap catches was more strongly influenced by habitat type than by sampling methods. This implies that for multi-species monitoring, differences in trap efficiency between habitats may be neglected, as far as habitat types remain well contrasted. We conclude that for the purpose of monitoring large arthropod assemblages in the long-term, a protocol based on operating a set of different and non-disruptive traps appears superior in design than summing a series of taxa-specific protocols

Bee conservation in Sub-Saharan Africa and Madagascar: diversity, status and threats

Sub-Saharan Africa and Madagascar contain a wealth of bee diversity, with particularly high levels of endemicity in Madagascar. Although Africa contains seven biodiversity hotspots, the bee fauna appears rather moderate given the size of the continent. This could be due to various factors, an important one being the dearth of bee taxonomists working in Africa and difficulties in carrying out research in many regions. Anecdotal observations suggest a very large number of undescribed bee species. A number of serious threats to this diversity exist, especially habitat destruction and degradation. Bee diversity in these regions is likely to be important for both agriculture and indigenous ecosystems, but is under-appreciated. Reliance on conserved areas such as National Parks will not be sufficient to preserve bee diversity in Africa and Madagascar; changes to land use practices and development of industries that facilitate conservation, such as ecotourism, will be essential. There is also a strong need to build regional expertise and infrastructure that can be used for documenting bee diversity, identifying the most urgent conservation issues, and implementing conservation strategies. Support from developed countries and international funding agencies is needed for this

A new species of Fidelia Friese, 1899 (Hymenoptera, Megachilidae), with a key to the species of the genus

A new species of Fidelia Friese, 1899 is described from southern Africa: Fidelia (Fideliopsis) whiteheadi Litman & Kuhlmann sp. nov. Diagnostic characters are provided to distinguish this species from others in the genus, particularly from the closely related F. hessei; an updated description for Fidelia hessei is also given. The host plant preferences and seasonal activity of F. whiteheadi Litman & Kuhlmann sp. nov. and F. hessei are discussed. Finally, a revised, illustrated key to species of the genus Fidelia is presented

Climate and food resources shape species richness and trophic interactions of cavity-nesting Hymenoptera

Aim Temperature, food resources and top-down regulation by antagonists are considered as major drivers of insect diversity, but their relative importance is poorly understood. Here, we used cavity-nesting communities of bees, wasps and their antagonists to reveal the role of temperature, food resources, parasitism rate and land use as drivers of species richness at different trophic levels along a broad elevational gradient. Location Mt. Kilimanjaro, Tanzania. Taxon Cavity-nesting Hymenoptera (Hymenoptera: Apidae, Colletidae, Megachilidae, Crabronidae, Sphecidae, Pompilidae, Vespidae). Methods We established trap nests on 25 study sites that were distributed over similar large distances in terms of elevation along an elevational gradient from 866 to 1788 m a.s.l., including both natural and disturbed habitats. We quantified species richness and abundance of bees, wasps and antagonists, parasitism rates and flower or arthropod food resources. Data were analysed with generalized linear models within a multi-model inference framework. Results Elevational species richness patterns changed with trophic level from monotonically declining richness of bees to increasingly humped-shaped patterns for caterpillar-hunting wasps, spider-hunting wasps and antagonists. Parasitism rates generally declined with elevation but were higher for wasps than for bees. Temperature was the most important predictor of both bee and wasp host richness patterns. Antagonist richness patterns were also well predicted by temperature, but in contrast to host richness patterns, additionally by resource abundance and diversity. The conversion of natural habitats through anthropogenic land use, which included biomass removal, agricultural inputs, vegetation structure and percentage of surrounding agricultural habitats, had no significant effects on bee and wasp communities. Main conclusions Our study underpins the importance of temperature as a main driver of diversity gradients in ectothermic organisms and reveals the increasingly important role of food resources at higher trophic levels. Higher parasitism rates at higher trophic levels and at higher temperatures indicated that the relative importance of bottom-up and top-down drivers of species richness change across trophic levels and may respond differently to future climate change

Floral hosts of leaf-cutter bees (Megachilidae) in a biodiversity hotspot revealed by pollen DNA metabarcoding of historic specimens.

South Africa is a megadiverse country with three globally recognised biodiversity hotspots within its borders. Bees in particular show high diversity and endemism in the western part of the country. Not much is currently known about the floral host preferences of indigenous bees in South Africa, with data only available from observational studies. Pollen metabarcoding provides provenance information by utilising DNA analyses instead of floral visitation and traditional microscopic identification to identify pollinator food plants, which can be time consuming and imprecise. In this study, we sampled pollen from leaf-cutter bees (Megachilidae) specimens maintained in a historic insect collection (National Collection of Insects, South Africa) that were originally collected from two florally important areas in South Africa (Succulent Karoo and Savanna) and used metabarcoding to determine pollen provenance. We also sampled pollen from leafcutter bee species with wider distributions, that extend across many different biomes, to determine if these 'generalist' species show relaxed floral host specificity in some biomes. Metabarcoding involved sequencing of the nuclear internal transcribed spacer 2 (ITS2) region. Amplicons were compared to a sequence reference database to assign taxonomic classifications to family level. Sequence reads were also clustered to OTUs based on 97% sequence similarity to estimate numbers of plant species visited. We found no significant difference in the mean number of plant taxa visited in the Succulent Karoo and Savanna regions, but the widespread group visited significantly more floral hosts. Bees from the widespread group were also characterised by a significantly different composition in pollen assemblage. The time since specimens were collected did not have an effect on the mean number of taxa visited by any of the bee species studied. This study highlights national history collections as valuable sources of temporal and spatial biodiversity data

Specialization of plant–pollinator interactions increases with temperature at Mt. Kilimanjaro

Aim: Species differ in their degree of specialization when interacting with other species, with significant consequences for the function and robustness of ecosystems. In order to better estimate such consequences, we need to improve our understanding of the spatial patterns and drivers of specialization in interaction networks. Methods: Here, we used the extensive environmental gradient of Mt. Kilimanjaro (Tanzania, East Africa) to study patterns and drivers of specialization, and robustness of plant–pollinator interactions against simulated species extinction with standardized sampling methods. We studied specialization, network robustness and other network indices of 67 quantitative plant–pollinator networks consisting of 268 observational hours and 4,380 plant–pollinator interactions along a 3.4 km elevational gradient. Using path analysis, we tested whether resource availability, pollinator richness, visitation rates, temperature, and/or area explain average specialization in pollinator communities. We further linked pollinator specialization to different pollinator taxa, and species traits, that is, proboscis length, body size, and species elevational ranges. Results: We found that specialization decreased with increasing elevation at different levels of biological organization. Among all variables, mean annual temperature was the best predictor of average specialization in pollinator communities. Specialization differed between pollinator taxa, but was not related to pollinator traits. Network robustness against simulated species extinctions of both plants and pollinators was lowest in the most specialized interaction networks, that is, in the lowlands. Conclusions: Our study uncovers patterns in plant–pollinator specialization along elevational gradients. Mean annual temperature was closely linked to pollinator specialization. Energetic constraints, caused by short activity timeframes in cold highlands, may force ectothermic species to broaden their dietary spectrum. Alternatively or in addition, accelerated evolutionary rates might facilitate the establishment of specialization under warm climates. Despite the mechanisms behind the patterns have yet to be fully resolved, our data suggest that temperature shifts in the course of climate change may destabilize pollination networks by affecting network architecture