Grevillea obtusiflora subsp. obtusiflora and subsp. fecunda Recovery Plan

NSW National Parks and Wildlife Service, September 2001
ISBN 0 731 36281 0

8 Management issues

8.1 Introduction

The management of the conservation of threatened species requires the development of a "recovery program" which considers (i) the biological and ecological aspects of the species; (ii) the social, political and organisational parameters that may affect the success or otherwise of the program; and (iii) the economic factors which may influence the operation of the program's implementation.

As such, this section identifies the management issues affecting Grevillea obtusiflora including the;

  1. limits of our current understanding of the taxon's biology and ecology,
  2. threats and reasons for decline, and
  3. social and economic factors which may influence the success or otherwise of the recovery plan.

8.2 Current level of understanding

Knowledge of the biology and ecology of Grevillea obtusiflora is far from complete, although previous management actions provide levels of information, particularly relating to reproductive strategies, significant information gaps lie in the areas of seed biology, fruit production, pollinators, genetic variation, and fire ecology.

Monitoring of the effectiveness of the actions in this Recovery Plan provides an opportunity to collect data to assist in understanding the ecology of these taxa and to make further management recommendations to ensure the survival of these taxa.

8.3 Threatening processes

The threatening processes affecting these taxa are: direct clearing associated with agricultural activities, direct damage by vehicular access, inappropriate fire regimes, and roadside management activities such as grading and weed spraying.

8.3.1 Unrestricted vehicular access

Grevillea obtusiflora subsp. obtusiflora

The largest sub-population of G. obtusiflora subsp. obtusiflora (O1) primarily occurs in Clandulla State Forest adjacent to forest roads. It is unlikely that the public will drive off road in these areas as there are few trees of interest to firewood collectors and present unsuitable conditions for motorcycle use. No such use has been observed at the site.

Clandulla State Forest receives a low level of public use ranging from recreational activities to small-scale removal of fencing timber under licence from State Forests of NSW. The poor timber quality at the site has limited timber production in this area. In planning harvesting operations State Forests of NSW undertakes comprehensive environmental assessments including searches for threatened flora and fauna.

State Forests of NSW may be able to exclude this area from timber harvesting. However, this cannot guarantee these sites will not be affected by activities where people operate outside their licence conditions or without a licence.

The majority of roads in Clandulla State Forest have been established for at least 30 years. Tables and barbeques were added to the picnic area on Carwell Creek in the late 1980s. However, visitor numbers remain low, mainly mountain bike riders and fisher people.

Vehicular access may increase the likelihood of introduction of soil pathogens, although the vulnerability of Grevillea obtusiflora subsp. obtusiflora to these is not known.

Grevillea obtusiflora subsp. fecunda

As some sites occur on road verges, there is potential threat from the direct impacts of vehicles driving over plants.

Similar to that occurring within Clandulla State Forest, a level of illegal off-road vehicle use occurs within Gardens of Stone National Park. Again similar to the Clandulla State Forest circumstance, there is no evidence to suggest that this activity is having an impact on Grevillea obtusiflora subsp. fecunda.

8.3.2 Fire

Despite Grevillea obtusiflora having fire survival strategies, fire can have a major influence on post-fire community composition and therefore habitat within an area. Habitats and the natural processes occurring within them need to be maintained in as natural a state as is possible. Inappropriate fire regimes can alter the operation of ecological processes, leading to changes in taxon presence and abundance, population composition and structure, as well as affecting associated factors such as pollinators and soil biota, all of which may play a role in the health of the plant and its habitat.

Grevillea obtusiflora subsp. obtusiflora

Prescribed burns are effected by the State Forests of NSW when fuel loads need to be reduced. In the habitat of G. obtusiflora subsp. obtusiflora, records show that regular fire events are uncommon. Ground fuel levels are low, possibly due to the low site quality producing less fine fuel, hence contributing to the infrequent fire regime. The main potential ignition sources are lightning, escapes from agricultural burning, and arson.

A firebreak was established during a wildfire in Clandulla State Forest in 1994 to protect private property and the township of Clandulla. This firebreak can be utilised to manage the fire regime within areas of G. obtusiflora subsp. obtusiflora habitat.

Grevillea obtusiflora subsp. fecunda

Due to their proximity to freehold land, some of the G. obtusiflora subsp. fecunda sites may be affected by future hazard reduction programs. This effect may be exacerbated by fuel reduction programs that incorporate regular prescribed burning regimes. It would be expected that a short inter-fire interval would be detrimental to G. obtusiflora subsp. fecunda. Prescribed burns for fuel reduction are carried out as required by Rylstone Shire Council.

G. obtusiflora subsp. fecunda habitat occupies a range of land tenures, hence is subject to widely varying fire management practices. These practices have been formulated without regard for the ecological requirements of this taxon. It is desirable that the ecological requirements of this taxon be considered when fire management actions or plans are being formulated.

8.3.3 Road Management Activities Grading and Slashing

Road widening works and slashing of roadside vegetation (up to two metres on immediate shoulders) is carried out by Rylstone Shire Council. This activity has the potential to direct affect the taxon at sites O2, F1 and F2. Weed Control
Grevillea obtusiflora subsp. obtusiflora

Herbicide application is a standard form of weed control carried out on roads by Rylstone Shire Council. Inadvertent application of herbicide to G. obtusiflora subsp. obtusiflora may cause plant death or reduced vigour. Road side herbicide spot spraying is a potential threat for this taxon, especially at Site O2.

Grevillea obtusiflora subsp. fecunda

Numerous agricultural weeds occur at Sites F1 and F2, as these sites adjoin cleared agricultural land. It is not known whether the weeds effectively compete with G. obtusiflora subsp. fecunda. As with G. obtusiflora subsp. obtusiflora, inadvertent application of herbicide may cause plant death or reduced vigour and fecundity.

As G. obtusiflora subsp. fecunda occurs on roads, it is subject to similar herbicide application and its potential effects, as have been described for G. obtusiflora subsp. obtusiflora.

8.4 Translocation

Translocation is defined as the "deliberate transfer of plants or regenerative plant material from one place to another, including existing or new sites or those where the taxon is now extinct" (Australian Network for Plant Conservation 1997). Translocation may also involve the removal of plant material to undertake an ex situ conservation program.

The translocation of G. obtusiflora subsp. obtusiflora and subsp. fecunda is not considered to be an appropriate conservation mechanism for the following reasons:

  • taxa numbers appear to be stable,
  • numbers of individual plants have not reached a critical stage, and
  • with the implementation of the recovery actions outlined in this Recovery Plan, the taxa should be adequately protected from further decline.

8.5 Social and economic issues

8.5.1 Social Issues

The main social impacts resulting from the implementation of this recovery plan will affect the local community in the vicinity of the sites. Increased awareness regarding the conservation of threatened species in a rural setting will help to bring about changes in social behaviour. These changes relate to the recognition of the value of remnant vegetation and responsibility for habitat management.

Negative social impacts are not expected, as the implementation is not expected to affect public land usage to any great extent, and modification of private land management patterns will occur on a consultative basis.

Another impact may be consideration of the taxa in any environmental impact assessment for proposed development. As an endangered species listed on the TSC Act, G. obtusiflora and its habitat must be considered prior to approval or consent being granted for a proposed development. Due to lack of development pressure in this area, it is not likely that a significant number of development proposals will be proposed in areas where the taxon or its habitat is present.

The continued consultation and liaison with the local community, Rylstone Shire Council, and relevant agencies will address and minimise social impacts arising from the conservation of the taxa.

8.5.2 Economic Considerations

The economic consequences of this recovery plan are those that are associated with its implementation. These include on-ground habitat management, conducting biological research and monitoring, establishing and disseminating to land managers ecological and population dynamics information, improved environmental assessment of activities which potentially impact on the taxa (including hazard reduction activities), community education and participation, and on-going recovery team coordination. These costs can be minimised by:

  • implementing a long-term strategic framework for managing the taxa and their habitat;
  • seeking funds from external sources, including research grants;
  • maintaining accurate information on the distribution and status of sub-populations; and
  • adopting a cooperative approach to management with the relevant land managers and the local community.

8.6 Taxa's ability to recover

It is not known whether G. obtusiflora subsp. obtusiflora and subsp. fecunda have always been naturally uncommon, or have suffered minor or substantial declines in populations and/or distributions. The long term persistence of these taxa in the wild will depend on maintenance of the existing populations and their habitat.

The maintenance of this taxon within botanical collections is important for the preservation of the genetic stock.

8.6.1 Taxa rarity

Grevillea obtusiflora has a restricted distribution and is only known to occur in the Cudgegong and Capertee valleys in the Central Tablelands of NSW. A low number of individual plants are present, threats to the taxon are operating, and the taxon's ecology makes it susceptible to threats and subsequent decline. Only one sub-population of G. obtusiflora subsp. fecunda is conserved within a conservation reserve (National Park or Nature Reserve) (Site F3).

8.6.2 Taxa viability

The viability of a taxon depends on the effectiveness of its reproductive mechanism, and this mechanism must also ensure the maintenance of genetic integrity. The genetic integrity of the populations of both G. obtusiflora subsp. obtusiflora and subsp. fecunda is not known.

Due to the lack of regular new genetic input from sexual reproduction and the exclusive clonality of G. obtusiflora subsp. obtusiflora the genetic diversity of the population may be low. However, Eriksson (1993) suggested that many clonal plants do not show signs of senescence and as a consequence possess almost unlimited fecundity.

8.6.3 Likelihood of recovery

The likelihood of the recovery of G. obtusiflora subsp. obtusiflora and subsp. fecunda is high if the recovery actions outlined in this plan are implemented, monitored and amended as required.