TY  - JOUR
A1  - Mayr, Antonia V.
A1  - Peters, Marcell K.
A1  - Eardley, Connal D.
A1  - Renner, Marion E.
A1  - Röder, Juliane
A1  - Steffan-Dewenter, Ingolf
T1  - Climate and food resources shape species richness and trophic interactions of cavity-nesting Hymenoptera
JF  - Journal of Biogeography
N2  - 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.
KW  - land-use change
KW  - species richness
KW  - trophic levels
KW  - wasps
KW  - feeding guilds
KW  - antagonists
KW  - bees
KW  - bottom‐up and top‐down control
KW  - elevational gradients
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-208101
VL  - 47
IS  - 4
ER  - 
TY  - JOUR
A1  - De Palma, Adriana
A1  - Abrahamczyk, Stefan
A1  - Aizen, Marcelo A.
A1  - Albrecht, Matthias
A1  - Basset, Yves
A1  - Bates, Adam
A1  - Blake, Robin J.
A1  - Boutin, Céline
A1  - Bugter, Rob
A1  - Connop, Stuart
A1  - Cruz-López, Leopoldo
A1  - Cunningham, Saul A.
A1  - Darvill, Ben
A1  - Diekötter, Tim
A1  - Dorn, Silvia
A1  - Downing, Nicola
A1  - Entling, Martin H.
A1  - Farwig, Nina
A1  - Felicioli, Antonio
A1  - Fonte, Steven J.
A1  - Fowler, Robert
A1  - Franzen, Markus Franzén
A1  - Goulson, Dave
A1  - Grass, Ingo
A1  - Hanley, Mick E.
A1  - Hendrix, Stephen D.
A1  - Herrmann, Farina
A1  - Herzog, Felix
A1  - Holzschuh, Andrea
A1  - Jauker, Birgit
A1  - Kessler, Michael
A1  - Knight, M. E.
A1  - Kruess, Andreas
A1  - Lavelle, Patrick
A1  - Le Féon, Violette
A1  - Lentini, Pia
A1  - Malone, Louise A.
A1  - Marshall, Jon
A1  - Martínez Pachón, Eliana
A1  - McFrederick, Quinn S.
A1  - Morales, Carolina L.
A1  - Mudri-Stojnic, Sonja
A1  - Nates-Parra, Guiomar
A1  - Nilsson, Sven G.
A1  - Öckinger, Erik
A1  - Osgathorpe, Lynne
A1  - Parra-H, Alejandro
A1  - Peres, Carlos A.
A1  - Persson, Anna S.
A1  - Petanidou, Theodora
A1  - Poveda, Katja
A1  - Power, Eileen F.
A1  - Quaranta, Marino
A1  - Quintero, Carolina
A1  - Rader, Romina
A1  - Richards, Miriam H.
A1  - Roulston, T’ai
A1  - Rousseau, Laurent
A1  - Sadler, Jonathan P.
A1  - Samnegård, Ulrika
A1  - Schellhorn, Nancy A.
A1  - Schüepp, Christof
A1  - Schweiger, Oliver
A1  - Smith-Pardo, Allan H.
A1  - Steffan-Dewenter, Ingolf
A1  - Stout, Jane C.
A1  - Tonietto, Rebecca K.
A1  - Tscharntke, Teja
A1  - Tylianakis, Jason M.
A1  - Verboven, Hans A. F.
A1  - Vergara, Carlos H.
A1  - Verhulst, Jort
A1  - Westphal, Catrin
A1  - Yoon, Hyung Joo
A1  - Purvis, Andy
T1  - Predicting bee community responses to land-use changes: Effects of geographic and taxonomic biases
JF  - Scientific Reports
N2  - Land-use change and intensification threaten bee populations worldwide, imperilling pollination services. Global models are needed to better characterise, project, and mitigate bees' responses to these human impacts. The available data are, however, geographically and taxonomically unrepresentative; most data are from North America and Western Europe, overrepresenting bumblebees and raising concerns that model results may not be generalizable to other regions and taxa. To assess whether the geographic and taxonomic biases of data could undermine effectiveness of models for conservation policy, we have collated from the published literature a global dataset of bee diversity at sites facing land-use change and intensification, and assess whether bee responses to these pressures vary across 11 regions (Western, Northern, Eastern and Southern Europe; North, Central and South America; Australia and New Zealand; South East Asia; Middle and Southern Africa) and between bumblebees and other bees. Our analyses highlight strong regionally-based responses of total abundance, species richness and Simpson's diversity to land use, caused by variation in the sensitivity of species and potentially in the nature of threats. These results suggest that global extrapolation of models based on geographically and taxonomically restricted data may underestimate the true uncertainty, increasing the risk of ecological surprises.
KW  - bee community
KW  - land-use change
KW  - intensification
KW  - geographic biases
KW  - taxonomic biases
KW  - global dataset
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-167642
VL  - 6
ER  -