Discussion

The results of my study overall fall in line with the notion of the importance of connectivity, area size, and other such basic factors regarding the presence or absence of species in their habitats. The information regarding the sizes of areas needed and how connected these areas is on its own important data regarding the conservative efforts for the Marsh Fritillary and other species living in a fragemented metapopulation state like it.

The results of the study regarding the benefits of adding friction to our connectivity models is however a bit more dubious. It is clear that adding friction can indeed have a positive effect on the relative strength of these models. However, going by the example set by this particular study, it is unclear whether that effort is either worth the additional computational power or if it is even a practical and realistic way of approaching the issue at hand.

Regarding the compuational effort, the benefits of the best possible Friction-Weighted model is a decrease of just above 2 AIC units or so. Compared that to what other studies deem “enough” to say a certain model is better to a point where it is worth using over other models, this study shows that is just barely enough to justify matrix friction as a factor. However, it is still above that threshold.

Regarding the realism aspect, other studies done on a similar butterfly species has actually found that exploited land has had suprising postive effects on the ecoogical system of dispersal and occupancy. This is worth noting, becuase taken at face value it seems strange that a exploited land such as a limestone quarry would be easier to traverse through rather than forest, grasslands, or even just a uninhabited Euclidean path. There are studies that showcase the negative effects of fragmentation on the viability of species metapopulations afterall. The question then becomes if the optimal model is just showing a possible version where the friction-weighted distance is stronger than the Euclidean Distance, with no bearing in reality.

Taken these two things into consideration, I would argue that further future studies in this field into not just the Marsh Fritillary outside this particular area is needed. The effects of friction on other species both landlocked and airborne, its effects on the same species in different ranges and habitat networks, researching the actual friction values of a species, and taking into account that different human land uses might cause more or less friction (this study equated the quarry to other land use types for the sake of simplicity) are different versions of this study I would like to see done.


In summary…

This study implies that adding friction to the matrix of a connectivity model can indeed explain tge system of occupancy better than ignoring it completely. However, the results in this study are not conclusive enough to say if that additional effort is worth the hassle, nor if it even works in reality with the actual fricion values of a species. More studies in different situations and different species needs to be done. Should an overall pattern be found, it could offer great guidelines regarding what matrix to enforce around the habitat of species that we would like to conserve in the future.