Mediterranean process-driven seafloor habitat sensitivity

Process-driven seafloor habitat sensitivity (PDS) has been defined from the method developed by Kostylev and Hannah (2007), which takes into account physical disturbances and food availability as structuring factors for benthic communities. It is a conceptual model, relating species’ life history traits to environmental properties. Physical environment maps have been converted into a map of benthic habitat types, each supporting species communities with specific sensitivity to human pressures. It is based on two axes of selected environmental forces.The "Disturbance" (Dist) axis reflects the magnitude of change (destruction) of habitats (i.e. the stability through time of habitats), only due to natural processes influencing the seabed and which are responsible for the selection of life history traits. The "Scope for Growth" (SfG) axis takes into account environmental stresses inducing a physiological cost to organisms and limiting their growth and reproduction potential. This axis estimates the remaining energy available for growth and reproduction of a species (the energy spent on adapting itself to the environment being already taken into account). It can be related to the metabolic theory of the ecology.The process-driven sensitivity (PDS) can be seen as a risk map that combines the two previous axes and reflects the main ecological characteristics of the benthic habitats regarding natural processes. Areas with low disturbance are areas with a naturally low reworking of the sediment, allowing the establishment of a rich sessile epifauna community, with K-strategy species. Areas with low SfG means that the environmental factors, even though there are not limiting, are in lower values, i.e. that it imposes a cost for species to live. In areas combining low disturbance and low SfG, big suspension-feeder species with long life and slow growth can often be found: these species are more vulnerable in case of added disturbance.

过程驱动型海底生境敏感性（Process-driven seafloor habitat sensitivity, PDS）由Kostylev与Hannah（2007）开发的方法所定义，该方法将物理扰动与食物可获得性作为塑造底栖生物群落的核心调控因子。它是一类将物种生活史特征与环境属性相关联的概念模型。研究人员将物理环境图转换为底栖生境类型分布图，每种生境类型对应对人类活动压力具有特异性敏感性的物种群落。该模型基于两个选定的环境作用力维度：“扰动（Disturbance, Dist）”维度反映仅由影响海底的自然过程所导致的生境变化（破坏）幅度，即生境随时间的稳定性——这类自然过程正是驱动物种生活史特征演化的选择压力来源。“生长潜力（Scope for Growth, SfG）”维度考量对生物体造成生理代价、限制其生长与繁殖潜能的环境胁迫。该维度可估算物种用于生长和繁殖的剩余能量（已扣除物种适应环境所需消耗的能量），其理论基础可关联至生态学代谢理论。过程驱动型生境敏感性（PDS）可被视为结合上述两个维度的风险分布图，能够反映自然过程影响下底栖生境的核心生态特征。扰动程度较低的区域，其自然沉积物再扰动强度较低，可孕育丰富的固着型底上动物群落，其中以K-策略物种为主。生长潜力较低的区域，则意味着环境因子虽未达到限制性水平，但整体处于较低区间，即物种在此类环境中生存需要付出更高的适应成本。在扰动程度低且生长潜力低的区域，通常可发现体型较大、寿命长且生长缓慢的滤食性物种；这类物种在面临额外人为扰动时会表现出更高的脆弱性。