当前位置: X-MOL 学术Freshwater Biol. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Freshwater crabs (Decapoda: Pseudothelphusidae) increase rates of leaf breakdown in a neotropical headwater stream
Freshwater Biology ( IF 2.7 ) Pub Date : 2020-05-21 , DOI: 10.1111/fwb.13524
Carol Yang 1, 2 , Seth J. Wenger 1, 2 , Amanda T. Rugenski 1, 2 , Ingo S. Wehrtmann 3, 4 , Scott Connelly 1, 2 , Mary C. Freeman 5
Affiliation  

  1. Freshwater crabs are the largest macroconsumers in many neotropical headwater streams, but few studies have examined their roles in ecosystem processes such as leaf litter breakdown. As omnivorous macroconsumers, freshwater crabs affect multiple trophic levels. They may directly increase leaf breakdown through fragmentation and consumption or indirectly decrease breakdown by consuming other macroinvertebrates, including shredders and detritivores.
  2. In a headwater stream in Monteverde, Costa Rica, we conducted an in‐stream experiment with 40 enclosures to quantify the effects of pseudothelphusid crabs on both leaf breakdown and macroinvertebrate colonisation of leaves. Half of the enclosures were randomly selected to contain two crabs (mean carapace width = 30 mm) and half were controls without crabs. We sampled mixed leaf packs from the enclosures on days 11, 19, 28, 34, and 42. We found the leaves of one species (Koanophyllon pittieri) almost completely decomposed by day 28 in both treatments (crab versus no crab). The other two leaf species (Meliosma idiopoda, Quercus brenesii) composed the remaining leaf mass at the end of the experiment.
  3. At 42 days, enclosures with crabs had faster rates of leaf breakdown than those without crabs (with crabs: k = −0.020; without crabs: k = −0.016; p = 0.034). This suggests that the magnitude of direct leaf breakdown by crabs, due to fragmentation, consumption, or manipulation of leaves, was greater than any indirect effects on leaf breakdown via crab consumption of other leaf‐consuming species.
  4. Macroinvertebrate composition based on taxa abundances or biomasses did not significantly differ between treatments (ANOSIM; p = 0.73 and p = 0.65, respectively). Shredder and detritivore abundances and biomasses increased significantly through time (ANOVA; p ≤ 0.001), but there was no evidence of an effect of crab presence (p > 0.2), nor were there significant interactions between crab presence and time (p > 0.3).
  5. This is one of the first studies to quantify the effects of pseudothelphusid freshwater crabs on leaf breakdown rates. Our results suggest that these crabs can play a significant role in detrital processing in neotropical headwater streams. This study has also demonstrated that short‐term enclosure experiments are useful in measuring in‐stream effects of crab activity on leaf breakdown.


中文翻译:

淡水蟹(十足目:Pseudothelphusidae)增加了新热带源水流中叶片的分解速度

  1. 淡水蟹是许多新热带源水流中最大的大型消费者,但是很少有研究检查它们在生态系统过程中的作用,例如凋落物分解。作为杂食性大量消费者,淡水蟹会影响多种营养水平。它们可能通过破碎和消耗而直接增加叶片分解,或者通过消耗其他大无脊椎动物,包括切碎机和碎屑而间接减少分解。
  2. 在哥斯达黎加蒙特维德的源头水流中,我们进行了一个有40个围栏的流水实验,以量化拟铁壳蟹对叶片分解和大型无脊椎动物定居的影响。随机选择一半的围栏容纳两只螃蟹(平均甲壳宽度= 30毫米),另一半是没有螃蟹的对照组。我们在第11、19、28、34和42天从围栏采样了混合叶包装。我们发现,在两种处理方式下,第28天,一种物种(Koanophyllon pittieri)的叶子几乎都被完全分解了(蟹对没有蟹)。在实验结束时,其余的两种叶种(Meliosma idiopoda栎木)组成了剩余的叶块。
  3. 在第42天,有螃蟹的围栏的叶子破裂速度要比没有螃蟹的围栏快(有螃蟹:k  = -0.020;没有螃蟹:k = -0.016;p  = 0.034)。这表明由于碎裂,消耗或对叶片的操纵而导致的蟹类直接叶片分解的强度大于其他食蟹类物种通过蟹类摄入对叶片分解的间接影响。
  4. 在处理之间,基于类群丰度或生物量的大型无脊椎动物组成没有显着差异(ANOSIM;p  = 0.73和p  = 0.65)。切碎机和食腐质丰度和生物量通过时间显著增加(ANOVA; p  ≤0.001),但没有的蟹存在(的效应的证据p  > 0.2),也没有蟹存在和时间之间显著相互作用(p  > 0.3) 。
  5. 这是第一批量化假铁壳淡水蟹对叶片分解速率影响的研究之一。我们的结果表明,这些螃蟹在新热带源水流的碎屑处理中可以发挥重要作用。这项研究还表明,短期围封实验可用于测量蟹活动对叶片破裂的影响。
更新日期:2020-05-21
down
wechat
bug