Principal Ecological Question Addressed

What is habitat fragmentation? How does habitat fragmentation affect bird populations and assemblages? What are the proximate and ultimate causes of these fragmentation effects? Why are bird assemblages in habitat fragments often nested? Are bird assemblages in regional habitat fragments nested by fragment attributes? If these assemblages are nested by fragment attributes, how can this pattern guide bird conservation on the landscape?


What Happens

Students survey birds in forest fragments in order to: (1) test whether bird assemblages are nested by attributes of habitat fragments and (2) identify thresholds in fragment attributes that are relevant to conservation planning. Students begin by studying the impacts of fragmentation on bird populations, the theory and analysis of assemblage nestedness, and identification of bird species. They read about and discuss proximate and ultimate causes of assemblage structure, survey organisms in forest fragments, use freeware to test for assemblage nestedness and graph results, compare the degree to which assemblages are nested by different attributes of habitat fragments, and generate conservation plans. To complete the experiment, students produce and present scientific research posters.


Experiment Objectives


Equipment/Logistics Required

Each student group needs:

The class needs:

The computer must have the following software (Microsoft Excel, GoogleEarth [freeware available on the internet], Nested [freeware provided)], and Threshold [freeware provided]). It must also have the minimum specifications necessary to run GoogleEarth. At the time of publication, these specifications were: Pentium 3, 500Mhz, 128M RAM, 400MB disk space, network speed: 128Kbits/sec, 3D-capable video card with 16Mbytes of VRAM, and 1024x768 "16-bit High Color" screen.


Summary of What is Due

Between the first and second lab period:

After the remaining field data have been collected during the fourth lab period, each group must:


Keyword Descriptors

Ecological Topic Keywords:

alien species, assemblages, biodiversity, biogeography, bird community structure, community ecology, conservation biology, dispersal, disturbance, exotic species, extinction, habitat fragmentation, human impacts, invasive species, landscape ecology, management threshold, native species, nest predation, nestedness analysis, urban ecology, urban sprawl, and wildlife management.

Science Methodological Skills Developed:

Classification, collecting and presenting data, correlation versus causation, data analysis, evaluating alternative hypotheses, field work, formulating hypotheses, graphing data, hypothesis generation and testing, identification skills, natural history, oral presentation, poster presentation, presence / absence analysis, statistics, random sampling, theoretical thinking, and use of spreadsheets.

Pedagogical Methods Keywords:

assessment, background knowledge, formal groupwork, and problem based learning.