Native, Wild Pigs (Sus scrofa) at Pasoh and Their Impacts on the Plant Community
Native, Wild Pigs (Sus scrofa) at Pasoh and Their Impacts on the Plant Community
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帕索的本地野猪（Sus scrofa）及其对植物群落的影响
DOI：
10.1007/978-4-431-67008-7_35
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
S. Thomas
中科院分区：
文献类型：
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作者：
Kalan Ickes;S. Thomas
尽管在帕索森林保护区（Pasoh FR），许多大型陆生哺乳动物目前已经灭绝或极其罕见，但当地的野猪（Sus scrofa）却在茁壮成长。1996年和1998年进行的样条线调查得出的密度估计值分别为47.0头和27.0头/km2。这是该物种有记录以来的最高密度。在Pasoh保护区维持如此高的生猪密度的重要因素可能是大型食肉动物的缺乏以及几乎环绕保护区的油棕种植园全年丰富的食物供应。最近有几项研究解决了如此高密度的猪可能对Pasoh FR林下植物群落的一些影响。为了量化猪的土壤生根和种子捕食对木本树苗的影响，在保护区中心的原始森林中建立了猪的隔离。两年后，封闭区域内木本植物的生长量、总茎密度、物种丰富度和株高生长均高于成对对照区。另一项研究调查了猪筑窝的流行程度。当准备好分娩时，怀孕的雌性会折断或连根拔起40-350厘米高的树和藤本树苗。这些茎被精心地堆成圆顶状的结构，雌性在这里分娩。每年对50公顷永久林地的西部25公顷的猪窝进行调查。在四年的时间里，共建立了600多个猪窝，平均密度为6.0个/公顷/年。根据对10个鸟巢的检查和周围地区的破坏情况，每个鸟巢平均有145根根茎被连根拔起，另有122根根茎被折断，留下了树桩。猪从每个巢周围平均244平方米的区域收集这些茎，破坏或杀死53%的木本林下植被，这些植被高度为70厘米，胸高< 2.0厘米。我们估计猪造成了1-2厘米胸径（DBH）大小类树木总死亡率的29%。猪还优先使用双龙心科树苗作为筑窝材料。在Pasoh FR，巢的建设创造了约85,000个树桩/km2，这表明受损植物的再生能力可能会对林下植被的更新和未来的物种组成产生很大影响。研究人员对1800多根树桩进行了36个月的检查，以调查再生。不同生活史特征和分类关联的种间繁殖成功率差异较大。在这项研究中，在19个最常见的家族中，梁龙科的树桩存活了36个月，存活率最低。总的来说，数据表明，如果保护区的猪数量继续过剩，那么在经济上和生态上都至关重要的双翅目动物可能会出现转移。
Although many large-bodied terrestrial mammals are presently extinct or exceedingly rare at Pasoh Forest Reserve (Pasoh FR), the native, wild pigs (Sus scrofa) are thriving. Line transect surveys conducted in 1996 and 1998 yielded density estimates of 47.0 and 27.0 pigs/km2, respectively. These are among the highest density estimates ever recorded for this species. Important factors contributing to the maintenance of such high pig density at Pasoh FR are likely the absence of large carnivores and an abundant year-round food supply in the oil palm plantations that virtually surround the reserve. Several studies have recently addressed some of the effects that such a high density of pigs may have on the understory plant community at Pasoh FR. To quantify the effects of soil rooting and seed predation by pigs on woody saplings, pig exclosures were constructed in the primary forest at the center of the reserve. After two years the number of woody plant recruits, total stem density, species richness, and height growth were greater inside enclosed areas than paired control plots to which pigs had access. Another study examined the prevalence of nest building by pigs. When ready to deliver young, pregnant females snap off or uproot tree and liana saplings 40–350 cm in height. These stems are meticulously piled into dome-shaped structures under which the female gives birth. Annual surveys of pig nests were conducted in the western 25-ha of the permanent 50-ha tree plot. More than 600 nests were located over a four-year period, for an average density of 6.0 pig nests constructed/ha/ year. Based on examinations of 10 nests and damage to the surrounding areas, each nest contained on average 145 uprooted stems and an additional 122 stems that were snapped off, leaving behind stumps. Pigs gathered these stems from an average area of 244 m2surrounding each nest, damaging or killing 53% of woody understory vegetation > 70 cm tall and < 2.0 cm diameter at breast height. We estimated that pigs caused 29% of the total mortality of trees in the 1–2 cm Diameter at Breast Height (DBH) size class. Pigs also preferentially used saplings of the Dipterocarpaceae as nest construction material. Nest construction created > 85,000 stumps/km2at Pasoh FR, suggesting that understory regeneration and future species composition may be influenced considerably by the resprouting abilities of damaged plants. More than 1,800 stumps were examined for 36 months to investigate resprouting. There were large differences in resprouting success among species with different life history characteristics and taxonomic associations. Stumps of the Dipterocarpaceae had by a wide margin the lowest survivorship at 36 months of the 19 most common families in the study. Overall, the data suggest that if pigs continue to be hyper-abundant in the reserve there could be a shift away from the economically and ecologically paramount Dipterocarpaceae.