Bowker Matthew A, Miller Mark E, Belnap Jayne, Sisk Thomas D, Johnson Nancy C
Southwest Biological Science Center, Canyonlands Field Station, U.S. Geological Survey, 2290 S.W. Resource Boulevard, Moab, UT 84532, USA.
Conserv Biol. 2008 Dec;22(6):1533-43. doi: 10.1111/j.1523-1739.2008.01036.x.
Conservation prioritization usually focuses on conservation of rare species or biodiversity, rather than ecological processes. This is partially due to a lack of informative indicators of ecosystem function. Biological soil crusts (BSCs) trap and retain soil and water resources in arid ecosystems and function as major carbon and nitrogen fixers; thus, they may be informative indicators of ecosystem function. We created spatial models of multiple indicators of the diversity and function of BSCs (species richness, evenness, functional diversity, functional redundancy, number of rare species, number of habitat specialists, nitrogen and carbon fixation indices, soil stabilization, and surface roughening) for the 800,000-ha Grand Staircase-Escalante National Monument (Utah, U.S.A.). We then combined the indicators into a single BSC function map and a single BSC biodiversity map (2 alternative types of conservation value) with an unweighted averaging procedure and a weighted procedure derived from validations performance. We also modeled potential degradation with data from a rangeland assessment survey. To determine which areas on the landscape were the highest conservation priorities, we overlaid the function- and diversity-based conservation-value layers on the potential degradation layer. Different methods for ascribing conservation-value and conservation-priority layers all yielded strikingly similar results (r= 0.89-0.99), which suggests that in this case biodiversity and function can be conserved simultaneously. We believe BSCs can be used as indicators of ecosystem function in concert with other indicators (such as plant-community properties) and that such information can be used to prioritize conservation effort in drylands.
保护优先级通常侧重于珍稀物种或生物多样性的保护，而非生态过程。部分原因在于缺乏能反映生态系统功能的有效指标。生物土壤结皮（BSCs）在干旱生态系统中截留并保持土壤和水资源，且作为主要的碳和氮固定者发挥作用；因此，它们可能是生态系统功能的有效指标。我们为面积达80万公顷的大阶梯-埃斯卡兰特国家纪念区（美国犹他州）创建了生物土壤结皮多样性和功能的多个指标（物种丰富度、均匀度、功能多样性、功能冗余度、珍稀物种数量、生境专化物种数量、氮和碳固定指数、土壤稳定度以及表面粗糙度）的空间模型。然后，我们通过未加权平均法和基于验证性能得出的加权法，将这些指标整合为单一的生物土壤结皮功能图和单一的生物土壤结皮生物多样性图（两种不同类型的保护价值）。我们还利用牧场评估调查的数据对潜在退化进行了建模。为确定景观中哪些区域具有最高的保护优先级，我们将基于功能和多样性的保护价值层叠加在潜在退化层上。赋予保护价值和保护优先级层的不同方法均产生了极为相似的结果（r = 0.89 - 0.99），这表明在这种情况下，生物多样性和功能可以同时得到保护。我们认为生物土壤结皮可与其他指标（如植物群落特征）协同用作生态系统功能的指标，且此类信息可用于确定旱地保护工作的优先级。
