Local‐scale temperature gradients driven by human disturbance shape the physiological and morphological traits of dung beetle communities in a Bornean oil palm–forest mosaic. (9th May 2022) - Williamson, Joseph
Abstract: Temperature change is an often‐assumed, but rarely tested, mechanism by which sensitive species may decline in forest landscapes following habitat degradation, fragmentation and destruction. Traits mediate how species respond to environmental change, with physiological, morphological and behavioural traits key to determining the response of ectotherms to temperature. We collected data on traits linked to thermal sensitivity (critical thermal maxima, body size, cuticle lightness and pilosity) for 46 dung beetle species ( Scarabaeinae ) in a forest–oil palm mosaic in Malaysian Borneo. By combining these data with a large‐scale community sampling campaign (>59, 000 individuals sampled from >600 traps) and an airborne Light Detection and Ranging‐derived thermal map, we investigated how traits mediate species‐ and community‐level responses to temperature. Using hierarchical models, we found that critical thermal maxima predicted how species respond to maximum temperatures. These results were mirrored in community‐level analyses alongside similar patterns in other thermal traits. Increased body size and decreased pilosity were associated with higher temperatures, while cuticle lightness showed a complex relationship with temperature across the disturbance gradient. Our findings highlight the potential mechanisms by whichforest specialists decline in human‐modified landscapes, resulting in changes to community patterns and processes. Read the free Plain Language Summary for this article on the Journal blog. Abstract : Read the free Plain Language Summary for this article on the Journal blog. Abstrak: Perubahan suhu sering diandaikan namun jarang diuji, sebagai mekanisma di mana spesies‐spesies sensitif akan berkurang di lanskap hutan berikutan kemerosotan habitat, fragmentasi dan kemusnahan hutan. Trait mengetengahkan bagaimana sesuatu spesies bertindakbalas kepada perubahan persekitaran, dengan trait fisiologi, morfologi dan tingkah laku merupakan trait utama yang menentukan tindakbalas ektoterma terhadap suhu. Kami mengumpul data mengenai trait yang berkait dengan termal‐sensitif (kritikal termal‐maksima, saiz badan, kecerahan kutikel dan pilositi) bagi 46 spesies kumbang tahi (Scarabaeinae) di mozek hutan kelapa sawit di Borneo Malaysia. Dengan menggabungkan data‐data ini dengan data persampelan komuniti yang berskala besar (>59, 0000 individu disampel daripada >600 perangkap) dan peta daripada termal‐udara LiDAR, kami menyelidik bagaimana spesies kumbang tahi dengan trait‐pengantara spesies dan peringkat komuniti bertindakbalas kepada suhu. Dengan menggunakan model hierarki, kami mendapati bahawa kritikal termal‐maksimal meramalkan bagaimana spesies kumbang bertindakbalas terhadap suhu maksimum. Keputusan ini dicerminkan melalui analisis peringkat komuniti disamping corak yang sama pada trait‐trait termal yang lain. Pertambahan saiz badan dan pengurangan pilositi berkait dengan suhu tinggi manakala kecerahan kutikel menunjukkan perkaitan kompleks suhu merentang gradien gangguan hutan. Penemuan kami menegaskan mekanisma yang berpotensi dalam menyebabkan kemerosotan spesies khusus hutan di lanskap yang telah diubahsuai yang mengakibatkan perubahan kepada corak dan proses komuniti.