铁木森林国家保护区生物调查

人类的影响

非法移民交通: There was extensive evidence that undocumented immigrants use the Monument, 大部分是以倾倒在营地的垃圾的形式, 小网站, 沿着旅行路线. We also encountered several large groups of people in heavily-loaded vans, 皮卡, 桩基卡车, 步行. It is difficult to evaluate the biological damage this traffic may be causing, but the huge numbers of people passing through presumably cause significant impacts. We encountered a number of well-traveled roads that served no apparent function to ranchers or tourists. They all had in common that they provided access from the Tohono O’odham Reservation via gates or holes cut in the boundary fence. 许多洗澡间也有大量的人流量. 事实上，罗斯克鲁奇的大部分大型洗浴场, 银钟, and West 银钟 mountains and the Aguirre Valley had evidence of immigrant traffic (huge quantities of clothing, 塑料水瓶, 有西班牙语标签的食品容器, 还有几辆废弃的自行车). There is so much traffic in some washes that the people may be disturbing the biota by trampling seedlings and frightening wildlife.

一条道路最近在锯齿山附近的山坡上燃烧起来.

越野驾驶: Only a few of our plots were scarred by off-road vehicles and in most cases vehicles had not been far off established roads. The exceptions were associated with undocumented immigrant traffic. We found several staging areas hidden in thickets of vegetation, with tracks leading over crushed vegetation into them (and large piles of trash at the sites). Driving off-road is nonetheless a significant threat to the ecological integrity of 铁木森林 National Monument because of the easily-damaged soils and the slow recovery 利率 of most damaged desert plant species (Lovich and D. Bainbridge 1999, Gillette and Adams 1983, Wilshire and Nakata 1976, Webb et al. 1978).

Vehicle tracks in a wash near Ragged Top that is posted against driving. 看到 洗画廊 有关更多图像和信息.

在洗澡间驾驶在洗澡间开车是很广泛的. Most of the nonrocky washes we visited that were wide enough for an ORV had tracks, 包括几个签名和路障. This activity inflicts serious damage to xeroriparian communities. Shrubs often establish in wash channels in between scouring floods. In wet winters the channels support dense stands of annual plants, which in turn become a major food source for many species of wildlife. In drier years when annuals do not grow elsewhere they thrive in the deeper soils of washes; at these times the foliage and seeds are particularly important for wildlife. Washes occupy a tiny percentage of the land surface of the Lower Colorado River Valley subdivision of the Sonoran Desert, but most of the biomass of plants and animals is concentrated in this habitat. In the driest areas west of IFNM up to 90% of the plant and bird life is restricted to washes (California Desert 保护 Area Plan 1980). Even light vehicle traffic severely disrupts this growth and reduces overall forage, 并大大减少了野生动物密度(Luckenbach, 1978), Busack和Bury 1974年, Bury等人. 1977).

对植物的损害 (收割、破坏财物等.): We found numerous examples of saguaro cutting and one case of ocotillo cutting. In the cases of the 仙人掌, the plants had been cut near the ground and the skeletons were gone. 尽管广泛, most of the saguaro harvesting appeared to be fairly old and not common in any one area. 这似乎不是什么大问题. 2022世界杯下注遇到了一些破坏植物的例子, mostly gunshot wounds; they are most visible on 仙人掌. One of these sites had been vandalized only a few days before we discovered it; there were hundreds of spent shells, 粘土鸽子, 留下的垃圾. Two palo verde trees had been shattered by high-powered rifle bullets. There were several other places where trees had been cut as if for firewood. In one section of Cocío wash the cuts ranged from very recent to quite old (mesquites had regrown major limbs). 这片土地已被采伐多年. The cut trees were mostly mesquites, but a few were ironwoods.

大威力步枪对帕洛佛得角的破坏. There are reports of similar vandalism to ironwood trees in the Monument.

射击者留下的垃圾. 这个地方离公路一英里远.

营地: We found several campsites evidently made by tourists or hunters. The disturbance to soil and plants was minimal and there was little trash. We did not try to determine whether ironwood was used in the campfires. Burning of ironwood should not be allowed (see discussion on 铁木的寿命).

放牧: We observe little negative impact to vegetation from grazing except in the immediate vicinity of artificial water catchments and in some washes. 还有几个地方, 尤其是在破顶附近, 哪里的大铁树下有牛棚. These trees have barren, disturbed soil beneath their canopies. 2022世界杯下注不是牧场专家, 而是树苗的存在, 仙人掌, 大多数地块上的其他植物, and numerous grasses that were going to seed even during these two drought years suggest that current levels of grazing pose no threat to the general health of the ecosystem in 铁木森林 National Monument. 有两个问题需要进一步调查. 一些洗衣店被大量浏览. Because of the rarity and sensitivity of xeroriparian woodlands, further study is recommended to verify that wash vegetation is maintaining viable recruitment of new plants. 大型铁木有浓密的树冠, and we have assumed that the usual absence of other plants beneath them is due to the heavy shade. But the possible influence of cattle has not been determined.