Investigating Metapopulation Responses to Landscape-Level Habitat Changes

Jakob Goldner, Purdue University

Abstract

The study of landscape structure and configuration is firmly established as integral to the continued advancement of ecology. The configuration of resource patches can have far-reaching implications for biodiversity, metapopulation dynamics, community structure, and habitat quality. Human activities, such as forestry, agriculture, and residential construction alter patch configuration by breaking larger patches into smaller fragments. This frequently results in pronounced, unforeseen consequences for species. The fragmentation and shrinking of habitat patches can lead to changes in the environmental conditions within the remaining patches (e.g., degradation), prompting responses from local populations. These responses can, in turn, cause changes to the metapopulation structure on large spatial scale.I examined the relationship between the degree of habitat fragmentation (edge density), and forewing lengths of the ebony jewelwing damselfly (Calopteryx maculataBeauvois, Odonata: Calopterygidae). I used correlated random walks to determine the biologically relevant landscape area over which forest fragmentation was calculated. Then, I used Moran’s I to determine the spatial scale of wing length response to fragmentation. I found that wing lengths increased with edge density. I also found that wing lengths were spatially autocorrelated at distances below 5 Km. These findings suggest that damselflies adapt to changes in forest fragmentation at a relatively small spatial scale.Next, I assessed the slime mold Physarum polycephalum’s usefulness as a microcosm of dispersal in fragmented landscapes. Slime mold plasmodia were placed in dishes with oat patches of varying sizes and distances. The probability of each patch type being colonized first was compared to predictions of patch occupancy based on C. maculata. Patches that were nearer or larger were likely to be colonized before patches that were more distant, or smaller. Observed patch occupancy matched model predictions when only patch distance was varied, but not when patch size was varied. These results suggest that P. polycephalumhas the potential to serve as a useful microcosm of dispersal in patchy landscapes. However, more testing is needed to develop the microcosm system.Finally, a lesson plan was developed to teach high school students about the concepts of landscape ecology and connectivity. An emphasis was placed on using active learning techniques, which have been demonstrated to result in greater understanding than traditional lecture formats.The lesson plan incorporates an education boardgame, Humans & Habitats, that I developed to illustrate how the conflicting goals of resource managers impact habitat connectivity. It also incorporates a scientific inquiry activity that uses P. polycephalumto test predictions about the effect of altered connectivity. The lesson plan and materials will be available to members of the public, free of charge.

Degree

Ph.D.

Advisors

Holland, Purdue University.

Subject Area

Science education|Ecology|Education|Forestry

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