Dissertation Research: Predator-dependent Species-area Relationships in Ozark Glades

栖息地越小，物种就越少。这种物种-面积关系是预测生境破坏对物种灭绝影响的基础。这一关系的斜率决定了随着更多栖息地被破坏，有多少物种会灭绝。陡峭的SAR表明，栖息地面积的微小减少将导致广泛的物种灭绝。然而，栖息地的破坏也消除了对栖息地需求大的顶级捕食者，这可能会减少猎物物种的灭绝。栖息地破坏对物种灭绝的这些相互矛盾的影响表明，随着栖息地破坏的增加，顶级捕食者的减少可能会改变SAR斜率或猎物物种灭绝的速度。为了探索这一观点，Ryberg和Chase建立了一个数学模型，该模型预测捕食者会降低SAR斜率，这表明在捕食者存在的情况下，栖息地破坏对物种多样性的负面影响会减弱。他们在受到栖息地破坏威胁的生态系统中测试了这一假设，奥扎克沼泽地是岩石草原，那里有斑驳分布的掠食性项圈蜥蜴和它们的蚱蜢猎物。在有蜥蜴和没有蜥蜴的不同大小的空地上，蚱蜢猎物多样性的初步数据显示，在蜥蜴捕食者的存在下，蚱蜢的SAR较浅。该结果的一般性将通过额外的空间和时间抽样进行统计评估。这项研究将改善目前的林间空地恢复工作，通过与林间空地保护相关的科学推广项目促进公众教育，并增加本科生的研究机会，特别是那些来自代表性不足背景的学生。

Smaller habitats contain fewer species. This species-area relationship (SAR) is fundamental to predicting the effects of habitat destruction on species extinction. The slope of this relationship determines how many species go extinct as more habitat is destroyed. A steep SAR suggests that small decreases in habitat area will result in extensive species extinctions. However, habitat destruction also eliminates top predators with large habitat requirements, which could decrease prey species extinction. These conflicting impacts of habitat destruction on species extinction suggest that a loss of top predators might alter SAR slopes or the rate at which prey species go extinct with increasing habitat destruction. To explore this idea, Ryberg and Chase develop a mathematical model which predicts that predators will reduce SAR slopes, indicating that the negative impact of habitat destruction on species diversity will be diminished in the presence of predators. They test this hypothesis in an ecosystem threatened by habitat destruction, Ozark glades, which are rocky prairies that contain patchily distributed populations of predatory Collared lizards and their grasshopper prey. Preliminary data on grasshopper prey diversity in glades of varying size with and without lizards reveal a shallower grasshopper SAR in the presence of lizard predators. The generality of this result will be evaluated statistically with additional spatial and temporal sampling. This research will improve current glade restoration efforts, promote public education through scientific outreach programs related to glade conservation, and increase research opportunities for undergraduate students, particularly those from underrepresented backgrounds.