Grizzly bears and forestry: II: Grizzly bear habitat selection and conflicts with road placement

Timber harvesting and oil and gas extraction create ecological change beyond just the footprint of the resource extraction. These activities also create a permanent network of roads that can have lasting effects on forest ecology. Grizzly bears (Ursus arctos) suffer higher mortality when in close proximity to roads, yet bears in the foothills of west-central Alberta, continue to use these high-risk areas. We examined the hypothesis that bears were not necessarily attracted to logging roads but that these roads were placed in habitats that bears preferred. Using a resource selection function, we examined patterns in road placement and identified areas that had characteristics similar to roaded habitats (henceforth road-like habitats). We then quantified grizzly bear response to roads and road-like habitats. Of the 30 bears sampled, we found that 17 selected areas closer to roads than random and 11 selected road-like habitats. Road-like habitats were selected by subadults and some adult females but were not a good predictor of adult male habitat selection. Seasonally, grizzly bears selected habitats closer to roads in spring and early summer but selected road-like habitats more in late summer and fall, indicating that bears may be attracted to disturbed habitats in spring and undisturbed habitats in fall. We conclude that roaded habitats were selected by some grizzly bears but road placement in low-elevation valleys alone does not account for the strong selection preference. Although road placement likely plays a role, other factors such as clearcut association with roads may compound the attractiveness of roaded habitats to grizzly bears. The tradeoff between mortality risk and high-quality forage near roads must be addressed to prevent these areas from acting as attractive sinks.     

Grizzly bears and forestry: I. Selection of clearcuts by grizzly bears in west-central Alberta,Canada

We examined if clearcuts were selected as habitats by grizzly bears (Ursus arctos L.) in west-central Alberta during three seasons: hypophagia, early hyperphagia, and late hyperphagia. Our objectives were to describe seasonal habitat selection of clearcuts using resource selection functions at two scales. At the first scale, we assessed patch or third-order selection by comparing use (radiotelemetry) with study area-wide random locations and a dummy variable identifying whether locations occurred within or outside of clear-cut boundaries. At the second scale, we assessed within-patch or fourth-order selection by comparing locations (use and random) found within clearcuts and environmental covariates of terrain, silviculture, and landscape metrics. Finally, we examined diurnal versus crepuscular/nocturnal use of clearcuts by comparing the two with an expected 50:50 ratio.At the third-order scale, grizzly bears used clearcuts with respect to their availability for hypophagia and late hyperphagia, while selecting clearcuts more than expected during early hyperphagia. Fourth-order habitat selection revealed that landscape metrics, silviculture, and terrain were important predictors of grizzly bear use during hypophagia and late hyperphagia, while terrain appeared to be the most important predictor during early hyperphagia. Overall, grizzly bears avoided clear-cut interiors and preferred clearcuts with higher perimeter-to-edge ratios. Clearcuts were significantly more likely to be used during crepuscular/nocturnal periods. Intermediate-aged (∼30 years old) clearcuts were selected during hypophagia, whereas recent and old clearcuts were selected during late hyperphagia. Bears tended to avoid clearcuts with Donaren mound preparation, while selecting clearcuts with Bracke or shark-fin barrel dragging. These results suggest that landscape metrics, site preparation history, terrain, and season were important factors determining the use of clearcuts by grizzly bears. Future forest planning should strive to maximize habitat quality by: (1) increasing perimeter-to-edge ratio for clear-cut shapes; (2) using low impact and/or positively associated site preparation treatments like Bracke and shark-fin barrel dragging; and (3) limiting human access to areas predicted as high-quality habitat.     

Behavior of Brown Bears (Ursus arctos) in Captivity during Mating Season

IntroductionBrownbearisanen~redspecies.ThereisverylowwiahonOfbroWnbearsinthefie1d.Theanificialbredngincaghvitybecon1esaveryimPOrtantaPProachtoiareasethenumberofbearsandtorecoverwildbearresources.ThempseofthisstUdyistoProvidebasicbouSeAninfOnnationfOrthesu…     

Grizzly bears and forestry: I: Road vegetation and placement as an attractant to grizzly bears

Today's growing demand for timber is increasing road development in once roadless forest ecosystems. Roads create both local changes in plant communities and landscape-level changes in forest connectivity. Roads also increase human access, which can be detrimental to species such as grizzly bears. Because most grizzly bear mortalities occur near roads, we examined grizzly bear attractants near roads, which could increase bear use of roadsides and consequently increase human/grizzly bear interactions. We measured the prevalence of 16 grizzly bear foods near roads and examined patterns in road placement to better understand use of roaded habitats by grizzly bears in west-central Alberta. We found that roadsides had a higher frequency of ants, Equisetum spp., Taraxicum officinale, Trifolium spp., graminoids, and sedges; whereas, interior forest stands had a higher frequency of Shepherdia canadensis, Vaccinium myrtilloides, V. vitis-idaea, and ungulate pellets, an indicator of ungulate presence. In addition, roads near water had a greater occurrence of Arctostaphylos uva-ursi and Equisetum spp. than roads not near water, indicating that road placement influenced bear food diversity. Patterns in road placement varied between the upper and lower foothills, although models for the lower foothills predicted road placement in both regions. In the lower foothills, roads were constructed at low elevation, low soil moisture, high sun exposure, and intermediate terrain ruggedness, possibly similar to sites selected by bears. Reducing grizzly bear foods near roads should involve decreasing the width of roadside ditches, banning the planting of clover (Trifolium spp.), and reevaluating road placement in areas with high grizzly bear density.     

抓住机遇,迎接挑战,促进西双版纳茶业发展

分析我国加入WTO后茶业的机遇和面临的严竣问题 ,提出西双版纳茶业发展应加速低产茶园改造 ,推广无性系良种 ;保护茶园生态 ,应用生物技术 ;调整产品结构 ,开拓国内外市场 ;建立龙头产业 ,实施名牌战备等四项建议。随着中国加入WTO步伐的加快 ,为我国茶叶出口创造了前所未有的机遇 ,中国是世界产茶大国 ,19世纪几乎垄断了整个世界茶叶市场 ,进入 2 0世纪 ,肯尼亚、斯里兰卡后来居上。 1999年全国茶叶产量达 6 8万t,出口仅2 0 .2 9万t,云南茶叶产量 7.5万t,出口仅 1.0 3万t,版纳茶叶产量 1.5万t,几乎全部内销。国茶出口不畅 ,其主要原因是受经营机制和产品质量的制约 ,如何抓住中国加入WTO的机遇 ,振兴国茶在国际市场的声誉 ,促进版纳茶业再上新台阶 ,必须认真分析存在的问题 ,改革现行茶叶经营机制 ,依靠科技进步 ,提高产品的产量和质量     

Wertszuwachsprozent, Wirtschaftszinsfusz, Kapitalisierungszinsfusz

Ohne Zusammenfassung     

中国无忧树、海南红豆、火焰树、炮仗花

中国无忧树（火焰花）苏木科Saraca dives Pierre常绿乔木,高10～25m。树皮灰褐色,平滑,皮孔明显,内皮层淡红色;幼枝近方形而略扁,两侧具凹槽。树冠广卵形。叶互生,一回偶数羽状复叶,小叶4～7对,下部一对较小;小叶片近革质,长圆形至长圆状披针形,     

幌伞枫、团花、柚木、红背桂

<正>幌伞枫(罗伞树)Heteropanax fragrans(Roxb.)Seem.常绿乔木,高8~30 m。树皮暗灰色,纵裂,具圆形明显凸起皮孔,内皮淡紫红色;枝条短粗,茎枝嫩时具"V"形叶柄痕迹。树冠圆伞形。叶大,互生,多在茎枝顶部聚生,通常三至四回羽状复叶,羽片和小叶均对生;小叶近革质,椭圆形或卵形,长6~15 cm,宽3~7 cm,先端尾尖或突尖,基部宽楔形或近     

苏铁、木麻黄、夹竹桃、黄花夹竹桃

<正>苏铁(铁树、凤尾蕉)Cycas revoluta Thunb.苏铁科棕榈状常绿灌木或小乔木,高1～6 m。茎干单生或有分枝和丛生,粗壮,有叶柄残体和痕迹。树冠伞状。叶呈螺旋状于茎顶聚生,一回羽状,长0.5～1.5 m,宽15～35 cm;羽片多数,呈V形斜展,质地坚硬,条形,长5～20 cm,上面深绿色有光泽,先端刺尖,边缘向下反卷;叶柄两侧有齿状刺。雌雄异株,孢子叶球(球花)于茎顶部单生;小孢子叶球(雄球花)圆柱状宝塔形,直立,长30～70 cm,直径10～15 cm,小孢子叶长方状楔形,黄色;大孢子叶球(雌球花)球形或扁球形,直径20～30 cm,大孢子叶上部卵状扇形,边缘呈羽状     

马尾松、罗汉松、圆柏、侧柏

常绿乔木,高可达40m。树皮粗糙,呈不规则块状深裂,较厚,有树脂。树冠宽塔形或伞形。叶通常2针1束,稀3针;针叶较细柔,长8～20cm,直径0．9mm,具纵浅槽沟,边缘有微刺齿;叶鞘长6～9mm。球花单性。雌雄同株;雄球花生于新枝下部的苞腋,短圆柱状。黄色;雌球花生于新枝近顶端。卵形,淡紫色。