In defense of fences--response.

Abstract

The conclusion of Pfeifer et al. —that wildlife fencing should be context-dependent—echoes our own call for fencing decisions to be based on realistic assessments of the costs and benefits. We did not, as Pfeifer et al. suggest, state that fencing impacts were invariably negative, nor did we express a view that fence removal was imperative. Pfeifer et al. emphasize circumstances in which fences encircle isolated wildlife areas embedded in a matrix of human activity. However, as stated in our Perspective, many fences are constructed within contiguous wildlife habitat. Some of these fences are constructed for conservation purposes (e.g., to contain rhinos within a well-guarded area) and some serve other purposes (e.g., to delineate private property). Whatever their purpose, the resulting barriers to wildlife movement will have environmental impacts that should be considered when deciding whether to construct or remove fences. We agree with Pfeifer et al. that appropriately designed and well-maintained fences may contribute to wildlife conservation in small areas that are irretrievably isolated by human development. However, even in these circumstances, the likely benefits and costs need to be assessed carefully. As detailed in our Perspective, the anticipated benefits of fencing are often not realized, and so the prospects of success need to be realistically evaluated. Moreover, it is important to bear in mind that patches of wildlife habitat may be less isolated than they appear. In contrast with Pfeifer et al. 's statement, there is growing evidence of dispersal between apparently isolated wildlife areas, for example by tigers ([ 1 ][1]), wolves ([ 2 ][2]), and elephants ([ 3 ][3]). Such movements across the human-dominated matrix may improve the viability of relatively isolated populations, and the consequences of breaking such connectivity through fencing need to be carefully considered. We cited the paucity of fencing around reserves in North America as an illustration of alternatives rather than a model for other regions. Tolerance of wildlife movement in and out of many North American national parks may be related to sustainable use (including recreational hunting) on adjoining lands. This approach may or may not be appropriate elsewhere, but its success indicates that fencing is not the only way for societies to conserve large mammals while also pursuing economic development. Fencing interventions are often less straightforward than they seem, and may have lasting and irreversible impacts. Conservationists need to pay attention to both positive and negative impacts, and consider a range of interventions, not just fencing, to design long-term solutions to wildlife conservation. 1. [↵][4]1. P. A Reddy 2. et al ., PLOS ONE 7, 9 (2012). [OpenUrl][5] 2. [↵][6]1. P Ciucci, 2. W Reggioni, 3. L Maiorano, 4. L Boitani , J. Wildlife Manage. 73, 1300 (2009). [OpenUrl][7][CrossRef][8][Web of Science][9] 3. [↵][10]1. N Pinter-Wollman, 2. L. A Isbell, 3. L. A Hart , Biol. Conserv. 142, 1116 (2009). [OpenUrl][11][CrossRef][12][Web of Science][13] [1]: #ref-1 [2]: #ref-2 [3]: #ref-3 [4]: #xref-ref-1-1 View reference 1 in text [5]: {openurl}?query=rft.jtitle%253DPLOS%2BONE%26rft.volume%253D7%26rft.spage%253D9%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [6]: #xref-ref-2-1 View reference 2 in text [7]: {openurl}?query=rft.jtitle%253DJ.%2BWildlife%2BManage.%26rft.volume%253D73%26rft.spage%253D1300%26rft_id%253Dinfo%253Adoi%252F10.2193%252F2008-510%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [8]: /lookup/external-ref?access_num=10.2193/2008-510&link_type=DOI [9]: /lookup/external-ref?access_num=000271437400006&link_type=ISI [10]: #xref-ref-3-1 View reference 3 in text [11]: {openurl}?query=rft.jtitle%253DBiol.%2BConserv.%26rft.volume%253D142%26rft.spage%253D1116%26rft_id%253Dinfo%253Adoi%252F10.1016%252Fj.biocon.2009.01.027%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [12]: /lookup/external-ref?access_num=10.1016/j.biocon.2009.01.027&link_type=DOI [13]: /lookup/external-ref?access_num=000265338600021&link_type=ISI