塔斯马尼亚桉树森林是世界上碳密度最高的森林之一,但是预计的气候变化可能会破坏这个关键的碳汇的稳定。尽管非生物因素对森林生态系统碳动态的影响受到了广泛的关注,生物因素,如动物粪便的输入,人们对其了解较少。塔斯马尼亚恶魔(Sarcophilusharrisii)-一种食骨清除剂,可以摄取和溶解锁定在骨骼材料中的营养素-可以通过浓缩生物可利用的营养素来补贴植物和微生物的生产力(例如,氮和磷)在厕所里。然而,魔鬼人口密度急剧下降,受传染性癌症扩散的驱使,通过改变养分循环,可能对土壤有机碳(SOC)的储存和森林生产力产生低估的后果。这里,我们融合了实验数据和模型,以量化和预测各种气候和土壤质量未来下森林生产力和SOC的未来变化。我们发现魔鬼粪便显著增加了氮的浓度,铵,磷,和土壤中的磷酸盐,并将土壤微生物群落转移到以r-selected为主的群落(例如,快速生长)门。Further,在预期的温度升高和降水变化下,预计到2100年,魔鬼scat投入将增加地上和地下净初级生产力和微生物生物量碳。相比之下,当魔鬼scat被低质量的scat取代时(例如,来自非食骨清除剂和食草动物),森林碳库可能会增长更慢,或者在某些情况下,下降。一起,我们的结果表明,经常被忽视的生物因素将与气候变化相互作用,从而驱动塔斯马尼亚森林当前和未来的碳库动态。
Tasmanian eucalypt forests are among the most carbon-dense in the world, but projected climate change could destabilize this critical carbon sink. While the impact of abiotic factors on forest ecosystem carbon dynamics have received considerable attention, biotic factors such as the input of animal scat are less understood. Tasmanian devils (Sarcophilus harrisii)-an osteophageous scavenger that can ingest and solubilize nutrients locked in bone material-may subsidize plant and microbial productivity by concentrating bioavailable nutrients (e.g., nitrogen and phosphorus) in scat latrines. However, dramatic declines in devil population densities, driven by the spread of a transmissible cancer, may have underappreciated consequences for soil organic carbon (SOC) storage and forest productivity by altering nutrient cycling. Here, we fuse experimental data and modeling to quantify and predict future changes to forest productivity and SOC under various climate and scat-quality futures. We find that devil scat significantly increases concentrations of nitrogen, ammonium, phosphorus, and phosphate in the soil and shifts soil microbial communities toward those dominated by r-selected (e.g., fast-growing) phyla. Further, under expected increases in temperature and changes in precipitation, devil scat inputs are projected to increase above- and below-ground net primary productivity and microbial biomass carbon through 2100. In contrast, when devil scat is replaced by lower-quality scat (e.g., from non-osteophageous scavengers and herbivores), forest carbon pools are likely to increase more slowly, or in some cases, decline. Together, our results suggest often overlooked biotic factors will interact with climate change to drive current and future carbon pool dynamics in Tasmanian forests.