Controversy and Issues

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Across scientific literature there seems to be two standout controversies within the subject of habitat fragmentation.  These controversies include the aforementioned issue with the actual definition of habitat fragmentation and the issue of deciphering between the implications of habitat fragmentation versus habitat degradation.

Controversy of Definition

One might expect that a topic as large and important as habitat fragmentation would have a standing "textbook" definition.  Surprisingly this is not so. For example, Velazquez describes habitat fragmentation as "The discontinuous spatial distribution range, which originally formed as a single continuous unit" [5].  On the other hand, Groom et al. describe habitat fragmentation as "The disruption of extensive habitats into isolated and small patches; or the result of development in a large area where habitat is now fragmented into separate units; often applied to forested habitats that have been fragmented by agricultural development or logging." [7].  These represent minor nuances between scientific authors of what habitat fragmentation actually is.

 One primary paper in particular by Franklin et al. attempts to address the controversy with actually defining habitat as well as fragmentation [2].  This is especially an issue when it comes to birds as they consistently migrate and defining their habitat as well  as when it is fragmented can be unclear.  Franklin et al. suggest that fragmentation is both a process as well as an outcome.  Each of these situations are given their own definitions, those being "the state of habitat frag-mentation as the discontinuity, resulting from a given set of mechanisms. in the spatial distribution ofresources and conditions present in an area at a given scale that affects occupancy, reproduction, orsurvival in a particular species." for the "outcome" definition and "the process of habitat fragmentation as the set of mechanisms leading to that state of discontinuity." as the "process" definition.  They also suggest that there can be general as well as situational (as in the case with birds) circumstances in defining habitat fragmentation.  To address the issue of defining situational habitat fragmentation, they suggest four necessities need to be addressed, those being "1) what is being fragmented, (2)what is the scale(s) of fragmentation, (3) what is the extent and pattern of fragmentation, and(4)what is the mechanism(s) causing fragmen-tation.".

Issues With Defining Effects of Habitat Fragmentation Versus Habitat Loss.

The issue here is that habitat loss and habitat fragmentation almost ubiquitously go hand in hand.  This being the case, it can be hard to determine when a habitat is fragmented whether or not the observed effects are stemming solely from the fragmentation itself or if the loss of habitat is contributing.  This effect is especially difficult to distinguish if the study is being conducted on an area that has already been fragmented at the time of research.