https://nova.newcastle.edu.au/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://nova.newcastle.edu.au/vital/access/manager/Repository/uon:12848 Wed 11 Apr 2018 17:03:14 AEST ]]> https://nova.newcastle.edu.au/vital/access/manager/Repository/uon:43836 Tue 04 Oct 2022 11:46:39 AEDT ]]> https://nova.newcastle.edu.au/vital/access/manager/Repository/uon:17087 Sat 24 Mar 2018 08:00:33 AEDT ]]> https://nova.newcastle.edu.au/vital/access/manager/Repository/uon:6854 Sat 24 Mar 2018 07:47:40 AEDT ]]> https://nova.newcastle.edu.au/vital/access/manager/Repository/uon:27139 Sus scrofa) are recognised as having significant ecological impacts in many areas of the world including northern Australia. The full consequences of the introduction of pigs are difficult to quantify as the impacts may only be detected over the long-term and there is a lack of quantitative information on the impacts of feral pigs globally. In this study the effect of feral pigs is quantified in an undisturbed catchment in the monsoonal tropics of northern Australia. Over a three-year period, field data showed that the areal extent of pig disturbance ranged from 0.3-3.3% of the survey area. The mass of material exhumed through these activities ranged from 4.3tha^-1yr^-1 to 36.0tha^-1yr^-1. The findings demonstrate that large introduced species such as feral pigs are disturbing large areas as well as exhuming considerable volumes of soil. A numerical landscape evolution and soil erosion model was used to assess the effect of this disturbance on catchment scale erosion rates. The modelling demonstrated that simulated pig disturbance in previously undisturbed areas produced lower erosion rates compared to those areas which had not been impacted by pigs. This is attributed to the pig disturbance increasing surface roughness and trapping sediment. This suggests that in this specific environment, disturbance by pigs does not enhance erosion. However, this conclusion is prefaced by two important caveats. First, the long term impact of soil disturbance is still very uncertain. Secondly, modelling results show a clear differentiation between those from an undisturbed environment and those from a post-mining landscape, in which pig disturbance may enhance erosion.]]> Sat 24 Mar 2018 07:33:01 AEDT ]]> https://nova.newcastle.edu.au/vital/access/manager/Repository/uon:31066 Sus scrofa) are recognised as having significant environmental impacts. Here, we quantify the effect of feral pigs in a catchment (undisturbed by Europeans) in the monsoonal tropics of northern Australia. Field data collected over a 5-year period showed that the areal extent of pig disturbance ranged from 0·3 to 3·3% of the survey area (average 1·2%, σ = 0·9%). Mass of exhumed material was considerable and ranged from 4·3 to 36·0 Mg ha⁻¹ y⁻¹ (average 10·9 Mg ha⁻¹ y⁻¹). The excavations produce surface roughness which acts as sediment traps. Over the 5-year study period, there was no evidence to suggest that pigs produce any rill or gully erosion. There does not appear to be any relationship between rainfall amount and area disturbed or volume of material exhumed. However, a significant positive relationship was observed between number of disturbances and rainfall. The location of any disturbance appears to be random and has no relationship with topography or geomorphic attributes such as slope, upslope contributing area or wetness indices derived from a high-resolution digital elevation model of the site. While pigs are disturbingly relatively large volumes of soil, there is no clear evidence to support any increase in local erosion and soil structural change may be occurring slowly and only be observable over the long term.]]> Sat 24 Mar 2018 07:24:09 AEDT ]]>