Freshwater Protected Area Resourcbook

4.4 Assessing the effects of freshwater protected areas

A question may be asked: “do freshwater protected areas work in practice?”. In Australia, for example, several discharge springs from the Great Artesian Basin (GAB) are listed as ‘threatened ecological communities’ under the Commonwealth Environment Protection and Biodiversity Conservation (EPBC) Act – one protective mechanism available under Commonwealth authority, albeit not very effective at present. While in theory the EPBC Act can protect against major new developments which may constitute a threat to an area’s values, it cannot force proactive biodiversity management, and it cannot control a multitude of small widespread activities draining water flows from a site. Many GAB springs, known to include endemics (Ponder 2004) are already extinct as a result of drawdown resulting from excessive use of artesian water⁹⁶. A freshwater protected area without a guaranteed supply of appropriate environmental flows is unlikely to effectively protect biodiversity (Pringle 2001).
The scientific literature searchable through electronic means appears to contain relatively little addressing the issue of the biodiversity effects of freshwater protected areas, although there is abundant evidence of the benefits of large protected areas for terrestrial and marine biodiversity. The Ramsar Convention on Wetlands website (www.ramsar.org) contains considerable monitoring information on some of the world’s larger and more important freshwater protected areas. These reports are not peer-reviewed or independently-authored, and are open to interpretation of bias. While there are many successes documented, there are also considerable failings – and one could argue that the failings are likely to be understated.
Within the (relatively small) peer-reviewed literature of recent years dealing with the effectiveness of freshwater protected areas, the findings of Keith (2000:272) appear typical: “French natural protected areas are currently inefficient as far as fish conservation is concerned…”. Keith notes, however, the likelihood that aquatic birds and plants will tend to gain more tangible benefits from the protected areas examined – none of which were specifically declared to protect fish. Jackson et al. 2004, Madson & Clausen 1998, and Mathevet & Tamisier 2002 discuss protected areas for waterfowl: not surprisingly, small areas are relatively ineffective. Keith also draws attention to a lack of focussed management, population monitoring, and research specific to aquatic conservation issues. Keith’s findings are not dissimilar to those of an earlier paper (Lyle & Maitland 1992) reporting an investigation of the same question in Britain.
Only one global review of freshwater protected area efficacy has appeared in recent electronically-searchable literature, that of Crivelli (2002) – focusing solely on one group: fishes. Available evidence suggests that fishes have, overall, tended to gain little from existing protected areas – almost all of which were established for reasons other than the protection of fishes. Fishes may well be the most sensitive group in this regard, as threats are often particularly pervasive, intractable, and expensive to manage. Other groups such as waterfowl, amphibians, aquatic and riparian plants, aquatic invertebrates, and reptiles are all likely to benefit more from protected areas. Smaller, more sedentary animals are likely to gain relatively more benefit, as are those whose life-cycles do not involve migrations between widely spaced habitats – which of course are more difficult to encompass in protected areas of limited size. Obviously fishes migrating between freshwater and coastal habitats are particularly vulnerable, especially if heavily harvested.
The key threats to freshwater fishes relate to: (a) extraction and regulation of freshwater flows, (b) habitat degradation from a variety of sources including impediments to fish passage, pollution, degradation of in-stream and riparian vegetation, siltation and sedimentation, channelisation, mining and quarrying, (c) unsustainable harvesting pressures, and (d) introduction of alien species (Cowx 2002). The essence of protected areas is threat management, and here freshwater protected areas suffer some notable disadvantages.
In some instances, alien game fishes have been deliberately introduced to protected areas to enhance recreational angling opportunities, with consequent negative impacts on local fishes. Dams upstream or downstream of a protected area can restrict the movement of fishes on critical life-stage migrations. Water extraction outside the boundaries of a protected area can damage or destroy ecosystems within the protected area (Pringle 2001; also note comment above relating to GAB springs). Changes to riparian vegetation (stemming for example from catchment agricultural development) can alter detritic energy flows, and agricultural runoff carrying nutrients or pesticides can damage downstream ecosystems within ‘protected’ areas. As Saunders et al. (2002) suggest, protecting an entire catchment is desirable but seldom feasible. It is generally agreed that the efficacy of freshwater protected areas depends in large part on the way the surrounding catchment can be managed (Saunders et al. 2002, Crivelli 2002, Collares-Pereira & Cowx 2004)
Available evidence suggests that the success of freshwater protected areas around the world has been variable. This is perhaps not surprising, as connectivity issues present obvious management difficulties. Saunders et al. (2002) have suggested several general approaches which are likely to assist in effective planning and management of freshwater protected areas. The application of such approaches must be refined on a site by site basis. A thorough and enthusiastic application of these approaches should certainly result in significant benefits for freshwater biodiversity from protected areas, although some groups of biota are likely to benefit more than others.
In spite of the reservations expressed above, there is no doubt that freshwater protected areas are an important component to biodiversity management programs, and their systematic expansion in Australia is long overdue (Kingsford et al. 2005). The size of the protected area, and the management of the surrounding catchment will be critical for success.