Landscape connectivity for bobcat (Lynx rufus) and lynx (Lynx canadensis) in the Northeastern United States

Landscape connectivity is integral to the persistence of metapopulations of wide ranging carnivores and other terrestrial species. The objectives of this research were to investigate the landscape characteristics essential to use of areas by lynx and bobcats in northern New England, map a habitat availability model for each species, and explore connectivity across areas of the region likely to experience future development pressure. A Mahalanobis distance analysis was conducted on location data collected between 2005 and 2010 from 16 bobcats in western Vermont and 31 lynx in northern Maine to determine which variables were most consistent across all locations for each species using three scales based on average 1) local (15 minute) movement, 2) linear distance between daily locations, and 3) female home range size. The bobcat model providing the widest separation between used locations and random study area locations suggests that they cue into landscape features such as edge, availability of cover, and development density at different scales. The lynx model with the widest separation between random and used locations contained five variables including natural habitat, cover, and elevation—all at different scales. Shrub scrub habitat—where lynx’s preferred prey is most abundant—was represented at the daily distance moved scale. Cross validation indicated that outliers had little effect on models for either species. A habitat suitability value was calculated for each 30 m2 pixel across Vermont, New Hampshire, and Maine for each species and used to map connectivity between conserved lands within selected areas across the region. Projections of future landscape change illustrated potential impacts of anthropogenic development on areas lynx and bobcat may use, and indicated where connectivity for bobcats and lynx may be lost. These projections provided a guide for conservation of landscape permeability for lynx, bobcat, and species relying on similar habitats in the region.景观连通性（Landscape connectivity）对于广域食肉动物（wide ranging carnivores）及其他陆生物种（terrestrial species）的集合种群（metapopulations）存续至关重要。本研究旨在探究新英格兰北部地区猞猁（lynx）与短尾猫（bobcat）利用栖息地的关键景观特征，为两个物种分别构建生境可利用性模型，并探究该区域未来可能面临开发压力的片区内的景观连通性情况。研究基于2005至2010年间采集的定位数据（location data）开展马氏距离分析（Mahalanobis distance analysis）：数据涵盖佛蒙特州西部16只短尾猫与缅因州北部31只猞猁的定位记录，依据三个尺度展开分析，分别为1）局域（15分钟）移动尺度、2）每日定位点间直线距离尺度、3）雌性家域面积（home range size）尺度，以明确各物种所有定位点中一致性最高的环境变量。区分度最优的短尾猫模型显示，该物种会在不同尺度下响应生境边缘、遮蔽物可获得性及开发密度等景观特征；而区分度最优的猞猁模型则包含5个变量，分别为不同尺度下的自然生境、遮蔽物与海拔，其中猞猁首选猎物丰度最高的灌丛生境，对应每日移动距离尺度。交叉验证（cross validation）结果表明，异常值对两个物种的模型均无显著影响。研究为佛蒙特州、新罕布什尔州与缅因州内每个30平方米的栅格像素（pixel）计算了各物种的生境适宜性（habitat suitability）分值，并以此绘制该区域选定片区内保护地（conserved lands）之间的连通性图谱。未来景观变化预测结果展示了人为开发（anthropogenic development）对猞猁与短尾猫潜在栖息地的影响，并指明了二者可能丧失景观连通性的区域。该预测可为新英格兰地区猞猁、短尾猫及依赖相似生境的其他物种的景观通透性（landscape permeability）保护提供参考依据。