Integrating space and time: a case for phenological context in grazing studies and management

In water-limited landscapes, patterns in primary production are highly variable across space and time. Livestock grazing is a common agricultural practice worldwide and a concern is localized overuse of specific pasture resources that can exacerbate grass losses and soil erosion. On a research ranch in New Mexico with average annual rainfall of 217 mm, we demonstrate with a quantitative approach that annual seasons vary greatly and examine foraging patterns in Angus-Hereford (Bos taurus) cows. We define five seasonal stages based on MODIS NDVI: pre-greenup, greenup, peak green, drydown and dormant, and examine livestock movements in 2008. Daily distance traveled by cows was greater and foraging area expanded during periods with higher precipitation. A regression model including minimum NDVI, rainfall and their interaction explained 81% of the seasonal variation in distance traveled by cows (P<0.01). Cows explored about 81 ha·d⁻¹ while foraging, but tended to explore smaller areas as the pasture became greener (greenup and peak green stages). Cows foraged an average of 9.7 h daily and spent more time foraging with more concentrated search patterns as pastures became greener. Our findings suggest that phenological context can expand the capacity to compare and integrate findings, and facilitate meta-analyses of grazing studies conducted at different locations and times of year.     

Antioxidant,anti-amylase and anti-glycation potential of brans of some Sri Lankan traditional and improved rice (Oryza sativa L.) varieties

Brans of 23 traditional and 12 improved (both red and white) rice varieties in Sri Lanka were screened for anti-amylase and anti-glycation activities in vitro. Varieties which showed the highest inhibitory activities at screening were further investigated for anti-glucosidase and glycation reversing as anti-diabetic properties. The same varieties were studied for selected antioxidant properties. Significantly high anti-amylase and anti-glycation activities were observed for bran extracts of red varieties compared to white varieties at screening. Traditional red rice varieties, Masuran, Sudu Heeneti, Dik Wee and Goda Heeneti, exhibited significant and dose dependent anti-amylase, anti-glycation and glycation reversing activities. These varieties also showed marked antioxidant properties. It is concluded that brans of Sri Lankan traditional red rice varieties Masuran, Sudu Heeneti, Dik Wee and Goda Heeneti may be potential food supplements for diabetes.     

小兴安岭地区常见蚂蚁营养成分分析

为了更好地开发和利用东北林区丰富的蚂蚁资源,提供现实依据和理论基础,笔者对黑龙江省小兴安岭丰林保护区内2种常见蚁种（拟黑多刺蚁、赤蚁）体内营养成分进行分析测定,并对抗氧化物成分进行了比较。结果表明：拟黑多刺蚁与赤蚁均含有丰富的营养成分,粗蛋白质含量超过所有参比的畜禽类及鱼类食品,分别为62.4%、56.6%,经方差分析得知,两者差异性显著（P＜0.01）;维生素C含量分别为23.0、23.2 mg/g,差异性不显著（F=6.161;P＞0.05）;超氧化物歧化酶（SOD）含量分别为73.5、42.5 U/mL,SOD在拟黑多刺蚁体内含量比赤蚁体内含量高72.94%;过氧化物酶（POD）含量分别为7.1、4.7 U/mL,POD在拟黑多刺蚁体内含量比赤蚁体内含量高51.06%。因此,拟黑多刺蚁更适合做为蛋白质保健食品进行开发利用,2种蚂蚁体内抗氧化物成分高,可以做药业成分进行开发利用。     

Historical range of variability in eastern Cascades forests,Washington, USA

The historical range of variability (HRV) has been suggested as a coarse filter approach to maintain ecosystem sustainability and resiliency. The historical range of variability in forest age structure for the central eastern Cascade Range in Washington State, USA was developed from historical fire return intervals and the manner in which fire acted as both cyclic and stochastic processes. The proportions of seven forest structural stages calculated through these processes were applied to the area of each forest series within the central eastern Cascades landscape. Early successional forest stages were more common in high elevation forest than low elevation forest. The historical proportion of old growth and late successional forest varied from 38 to 63 percent of the forested landscape. These process-based estimates are consistent with those developed from forest structural information. HRV is a valuable planning tool for ecosystem conservation purposes, but must be applied to real landscapes with consideration of both temporal and spatial scale. This revised version was published online in July 2006 with corrections to the Cover Date.     

Rangeland Monitoring and Invasive Weeds

One of the serious biological obstacles that must be addressed in any comprehensive revision of rangeland ecological condition assessment is what to do with sites dominated by exotic self-invasive species. In certain cases such species have truncated succession so that with a bare minimum of disturbance, the sites will never return to dominance by native perennial species. Are such sites destined to remain always in what is defined as "poor" ecological condition. Many communities dominated by exotic annuals are closed to the recruitment of seedlings of native perennial species. At the same time the communities are open to invasion by other introduced species. Should susceptibility to future invasions be a criteria in assessing the ecological condition of rangeland communities. The sustainability of communities dominated by exotic invasive species is assessing the ecological condition of such communities. Deviation from the plant community concepts of range condition and trend judgement involves setting new benchmark standards. This is an endeavor fraught with many perils.     

The Struggle for a Uniform Monitoring System

Development of rangeland inventory and monitoring was initiated as early as in 1908. The early efforts were simple methods to establish rangeland stocking rates. With advancing scientific methodologies and the recognition for moitoring needs, the evaluation of range conditions and management planning increase well after WWII by a number of US federal agencies. By 1970s the environmental protection measures were first emphasized in the USA and were applied also to rangeland utilization. Since then the approaches and methodologies for evaluation of rangelands have changed periodically by accommodating the tenets of federal administrations. The methodologies applied have been geared either to support the environmental preservation or to support economic exploitation. There is still no system, however, for national or regional reporting on range conditions and trends. Local monitoring and management systems often lack scientific and objective basis. Local surveys, however, are important for evaluating existing conditions and should not be based on national reporting requirements. The ecological site concept has been adopted as the toxonomic unit for rangeland classification. It is important that monitoring methods are not biased, based on sufficient sample sizes, and not based on "estimations". The forage allocation based on one-time inventories are seriously flawed and the methods for evaluating stocking rates must be reevaluated. The same applies to the evaluating the rangeland "health." A unified national reporting system must be developed on scientific and objective basis.     

秦岭两侧黄牛群体遗传检测报告

以中心产区系统随机整群抽样对分布在秦岭两侧的秦川，西镇，平利３个地方黄牛品种（总头数各为６４２９３１，７２８４８，１３６４８）就下列遗传标记进行了检测：１．β血红蛋白（Ｈｂ），血清白蛋白（Ａｌｂ），后白蛋白（Ｐａ），运铁蛋白（Ｔｆ），后运铁蛋白ＯＰｔｆ），碱性磷酸酶（ＡＫＰ）６个位点的基因频率；２．Ｂ（黑色），Ｄ（稀释毛色），Ｓ（白斑的有无与类型），Ｂｒ（黧毛），Ｐｓ（皮肤黑斑），Ｉｎ（下腹部白斑     

Modeling species’ geographic distributions for preliminary conservation assessments: an implementation with the spiny pocket mice (Heteromys) of Ecuador

GIS-based modeling of a species’ environmental requirements using known occurrence records can provide estimates of its distribution for conservation assessments when other data are lacking. We used collection records, environmental variables, maps of land cover and protected areas, and the Genetic Algorithm for Rule-Set Prediction (GARP) to estimate the historical, current, and protected ranges of the spiny pocket mice present in Ecuador (Heteromys australis and H. teleus). The results suggest that ca. 52-63% of the distributional areas of H. australis in the country are intact, but suitable habitat in protected areas represents only approximately 11-13% of the species’ historical range there. The distribution of H. teleus has been much more reduced, with only ca. 13-19% of its historical distribution still forested and an estimated 2-3% intact and falling in protected areas. Our work highlights critical areas for future fieldwork and demonstrates an integrated approach to estimating a species’ current distribution for preliminary conservation assessments.     

Land degradation and livestock production in Zimbabwe's communal areas

This paper considers evidence of land degradation and its impact on livestock production systems in the communal areas of southern Zimbabwe. Various measures of rangeland degradation, using both primary and secondary production indicators, are examined. An apparent contradiction emerges between the high observed levels of soil erosion and the lack of impact on livestock production, as measured by population density trends, cattle production parameters, cumulative stocking levels and extraction rates. Farmers' observations of land degradation processes support the quantitative data. A possible resolution of the contradiction lies in an assessment of the spatial and temporal dimensions of degradation patterns; this points to the fact that current erosion is concentrated in areas that are not key grazing resources for cattle. The analysis suggests an agenda for degradation research that concentrates on evaluating the time span over which economic impacts of soil erosion are felt and assessing the spatial pattern of soil loss, with a special focus on key grazing resource patches.