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

• Explore the process of habitat fragmentation and how it alters habitat suitability and species occupancy
• Learn how to identify bird species in the field
• Use nestedness analysis to test hypotheses regarding the relative impacts of different aspects of fragmentation on bird assemblage structure and to generate a conservation plan
• Consider the benefits and risks of using presence/absence data and proximate ecological mechanisms to guide conservation efforts

Equipment/Logistics Required

Each student group needs:

• one pair of binoculars,
• one field guide to bird identification,
• one CD of bird songs by species common to the region,
• and one field notebook (preferably a smallish spiral bound book by rite-in-the-rain).

The class needs:

• access to at least one IBM compatible personal computer
• and one global positioning system unit (only necessary if the instructor needs help driving to fragments for the bird surveys).

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:

• each student must take a quiz on bird species identification,
• each student must read about fragmentation effects on birds (Faaborg 2002, chapters 4-5) and generate a brief written report explaining why smaller and more isolated habitat fragments tend to support fewer bird species than larger and less isolated habitat fragments,
• and each group must enter its estimates of fragment area and isolation into the provided spreadsheet and submit the edited spreadsheet.

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

• add the data from the bird surveys to the spreadsheet edited between weeks one and two and submit the edited spreadsheet,
• submit statistical results and meet with the instructor to discuss interpretation of results,
• submit a rough draft of the scientific research poster,
• and present the final draft of the scientific research poster to the instructor and class.

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.