Guiding the management of an agricultural pest: Indexing abundance of California meadow voles in artichoke fields

Nearly 100% of U.S. artichoke production comes from California and is concentrated in Monterey County. California meadow voles are damaging rodent pests that can threaten the profitability of growing artichokes. A practical population monitoring method can be invaluable to integrated pest management programs for guiding when and where control is needed and assessing control efficacy. The standard method for indexing vole populations in artichoke fields has been based on observing chewing on artichoke bracts placed throughout the field. Because toxicants are delivered on artichoke bracts, bias for population indexing is potentially introduced. We therefore compared artichoke bracts to nontoxic grain-based wax bait blocks as an alternative chewing medium for eliciting chewing observations for indexing abundance. We also compared the use of binary (presence-absence) observations of chewing to continuous measures (percent chewed). We considered the effect of three sizes of observation grids (4 × 4, 5 × 5, 6 × 6) for indexing. We conducted intensive trapping to determine number of voles known to be alive (KTBA) at each site as a basis for assessing which of the 12 indexing approaches (2 chewing mediums, 2 measurement types, 3 grid sizes) best tracked population abundance. The percent chewed on artichoke bracts for all grid sizes only marginally correlated with KTBA (∼0.5), whereas percent chewed on bait blocks correlated very well with KTBA for all grid sizes (∼0.9). Reducing continuous data to binary observations produced indices only weakly or negatively correlated with KTBA. Available resources would probably determine whether smaller grid sizes would be used for obtaining chewing observations.     

Fungal abundance and diversity in earthworm casts and in uningested soil

Earthworm casts and adjacent uningested soil from 30 different locations were compared to determine the abundance and diversity of fungal species. The casts contained larger fungal populations (g^-1 dry soil weight) and numbers of fungal species than the soil. Variations in these parameters between casts and soil were statistically significant (P=0.05). Fungal populations and the number of fungal species in casts and soil also varied significantly (P=0.05) between samples from different locations. A total of 27 fungal species were recorded from the casts and soil. Indices of dominance (0.084 casts; 0.14 soil) and general diversity (2.53 casts; 2.02 soil) demonstrated that the casts displayed more diverse fungal flora than the soil. The diversity of fungal species increased in earthworm casts after passing through the earthworm gut.     

Abundance of the Hawaiian monk seal in the main Hawaiian Islands

Most of the extant circa 1400 Hawaiian monk seals Monachus schauinslandi live in the Northwestern Hawaiian Islands (NWHI). However, an increasing number of sightings and births have recently occurred in the main Hawaiian Islands (MHI), where no systematic surveys of monk seals were conducted prior to 2000. We estimate that there were at least 45 seals in the MHI in 2000 and at least 52 in 2001, based on aerial surveys of all MHI coastlines, supplemented by sightings of seals from the ground. Moreover, annual births in the MHI have evidently increased since the mid-1990s. Weaned pups in the MHI are longer and have greater girth than those in the NWHI, perhaps reflecting greater per-capita abundance of prey resources. We think that Hawaiian monk seals have recently re-colonized the MHI, which were a very likely part of their historic range. Regardless, the MHI habitat appears to be favorable for continued increases of this endangered species.     

Distribution, status, and conservation needs of the golden-crowned sifaka (Propithecus tattersalli)

The golden-crowned sifaka is considered one of the world's most endangered primates. To evaluate the species' current conservation status we established its actual distribution and abundance, and assessed current threats that affect its survival. Study methods involved direct sifaka observations and interviews to local villagers. Propithecus tattersalli's distribution is restricted to the region comprised between the Loky and Manambato rivers. Throughout its range, the species is abundant and it can even be found in small forest fragments, although it was never observed at elevations above 700 m.a.s.l. Major threats to the species include habitat destruction through slash-and-burn agriculture, grass fires, wood and gold extraction, and poaching. Total population estimates range from 6100 to 10,000 individuals, with an effective population size of approximately 2500-4000 sifakas. Though sensitive to forest destruction, the species seems to be resilient to current levels of landscape fragmentation. We recommend the establishment of a system of protected areas throughout the Loky-Manambato region and the implementation of a “Flagship Species Program” utilizing the golden-crowned sifaka as a catalyst for a regional Conservation Management Plan.     

Comparative regeneration status in a natural forest and enrichment plantations of Chittagong （south） forest division, Bangladesh

于2002年4月至11月,对孟加拉Chittagong (南部)林区天然纯林和肥沃地人工林树种更新情况进行了比较研究。共设100个3m×3m的样地(天然林50个,人工林50个)。共记录天然林更新树种64个,苗木密度为24767株/hm2;人工林更新树种40个,苗木密度为18633株/hm2。天然林更新量最大的树种为Castanopsis spp.(2200 株/hm2),其次是Glochidion lanceolarium (2183 株/hm2);人工林更新量最大的树种为Dipterocarpus gracilis (2117株/hm2),其次是Anogeissus acuminata (2000株/hm2)。对天然林而言, Castanopsis spp 的相对密度最高(8.88%), Glochidion lanceolarium 的相对频度最高(7.36%),Syzygium spp. 的相对富有度最高(3.79%),Glochidion lanceolarium的重要值指数最高(18.24%);对人工林而言,Dipterocarpus gracilis的相对密度最高(11.36%),Glochidion lanceolarium的相对频度最高 (9.71%), Dipterocarpus gracilis的相对富有度最高(5.92%), Glochidion lanceolarium的重要值指数最高 (23.32%)。Dipterocarpus gracilis 常见种在天然林和人工林都有更新苗木,但人工林的苗木要高于天然林。天然更新的苗木非常密集,但由于人为的干扰,这些更新的苗木通常达不到径干生长期。表4参35。     

Relationships among abundance of galls,survivorship, and mortality factors in a cynipid wasp, <Emphasis Type="Italic">Andricus moriokae</Emphasis> (Hymenoptera: Cynipidae)

We describe the relationships among patterns of abundance of galls, survivorship, and mortality factors in the sexual generation of a cynipid wasp, Andricus moriokae, and detail the impacts of abundant parasitoid species on the survivorship of the cynipid in relation to the abundance patterns of galls. The mean number of galls per shoot, the frequency distribution of number of galls on a single shoot, and the mean number of galls per shoot in respective shoot size classes (the number of leaves per shoot) did not differ significantly between two sample trees. The relative impacts of the three mortality factors differed between trees, having different consequences for the survivorship of the cynipid. The rate of parasitoid attack, the main cause of mortality, was higher in the tree on which the cynipids survived better. On the other hand, the mortalities caused by gall predation and gall abortion were higher in the tree with the lower survival rate of the cynipid. Galls appeared more frequently on larger shoots on both trees. However, the survival rate and the mortality rates caused by three mortality factors did not differ among shoot size classes within each tree. The species composition of the parasitoid assemblage changed with shoot size, but the patterns of change differed between trees with similar abundance patterns of galls. Thus, the survivorship and mortality factors of the cynipid were probably not related to the abundance patterns of galls.     

夏玉米田间肥效试验与相关参数研究

[目的]确定夏玉米（ZeamaysL．）不同产量水平的最佳施肥量。[方法]开展临颍县2007～2010年夏玉米3414试验、氮肥用量试验、丰缺指标试验。[结果]在当前生产条件下,临颍县夏玉米最佳施肥量：高产水平下,氮肥最佳施用量为123．15～216．60kg／hm^2,磷肥为51．00—91．50kg／hm^2,钾肥为25．20～83．85k∥hm^2;中产水平下,最佳氮肥施肥量为109．35～187．50kg/hm^2,磷肥为36．30-79．35kg/hm^2,钾肥为11．55～60．75ke/hm^2;土壤养分含量高时取下限,土壤养分含量低时取上限。夏玉米100kg产量需肥量为：氮2．50kg,磷0．78kg,钾1．61kg;肥料利用率为：氮21．52％～26．20％,磷7．31％～8．43％,钾24．09％～33．96％;土壤养分供应量为：氮116．25～158．10k∥hm^2,磷39．90～82．65kg／hm^2,钾93．00～108．90kg／hm^2。[结论]该研究可为提高夏玉米测土配方施肥技术的普及率、覆盖率和到位率提供科学指导,以最大程度地发挥增产能力,使农民用较少的投入获得较大的收入。     

青海耕层土壤微量元素含量分析

[目的]为贵德县土壤微肥科学施用、作物合理布局和配方肥的确定提供基础数据。[方法]采用姜黄素比色法和原子吸收分光光度法,测定贵德县376个耕层土壤微量元素含量。[结果]贵德县有效微量元素平均含量B为0．339mg／kg,Cu为0．688mg／kg,Fe为3．798mg／kg,Mn为13．145mg／kg,Zn为2．554mg／kg,其中Fe、B含量缺乏,Cu、Mn含量适中,zn含量丰富。[结论]不同乡镇耕层土壤有效微量元素丰缺程度差异明显。不同土壤中有效微量元素含量之间差异不明显。     

Effect of landscape context on anuran communities in breeding ponds in the National Capital Region,Canada

Land cover change, predominantly habitat conversion to agricultural use and urbanization, has recently been recognized as the primary cause of biodiversity loss in terrestrial ecosystems. We evaluated the relative effects of urban and agricultural landscapes on anuran species richness and the abundance of six anuran species found at breeding ponds in and around the cities of Ottawa, Ontario and Gatineau, Quebec. We performed six call surveys at 29 permanent focal ponds surrounded by one of three landscape contexts: primarily urban, primarily agricultural, and primarily forested. We also measured three local pond variables to control for the effects of local habitat quality in our analyses. We found that anuran species richness was significantly lower in breeding ponds in urban landscapes compared to forested and agricultural landscapes, which exhibited no significant difference in species richness. The abundances of individual anuran species were also consistently lower in urban landscapes for all species except one, which exhibited no response to landscape type. Three species had their highest abundances in ponds in forested landscapes, whereas two species had their highest abundances in ponds in agricultural landscapes. We conclude that ponds embedded in urban landscapes support lower biodiversity than ponds in agricultural settings. We suggest that landscapes composed of a mosaic of forest and open habitats surrounding wetlands would hold the highest biodiversity of these species.     

Avian response to warm-season grass use in pasture and hayfield management

Populations of most avian species associated with grasslands have declined in North America over the last few decades. These declines may be related, in part, to changes in species composition and management of pastures and hayfields. The incorporation of native, warm-season grasses into pasture and hayfield management has been suggested as a means of providing suitable habitat for birds in agricultural areas. To examine this, we compared avian abundance, richness, and reproductive success in warm- [i.e. switchgrass (Panicum virgatum) and big bluestem (Andropogon gerardii)] and cool-season grass [i.e. orchardgrass (Dactylis glomerata)] fields on private farms in southwest Pennsylvania. Point counts, nest monitoring, and vegetation sampling were conducted on nine pairs (warm- and cool-season grass) of fields in 1996, and 12 pairs of fields in 1997. Compared with cool-season grass fields, warm-season grass fields supported a greater abundance and richness of birds, including several declining species [e.g. song sparrows (Melospiza melodia), field sparrows (Spizella pusilla), chipping sparrows (Spizella passerina), grasshopper sparrows (Ammodramus savannarum), and vesper sparrows (Pooccetes gramineus)]. Additionally, due to lower nest destruction and depredation rates, birds in warm-season grass fields had greater nest success and fledge rates. The positive response of birds to the use of warm-season grasses in pastures and hayfields appears to be due to the increased availability of undisturbed cover. Thus, the establishment of warm-season grasses in pastures and hayfields should be an avian conservation and management priority. Convincing farmers to use warm-season grasses in their fields should not be difficult, as several state and federal programs fund their establishment, and the use of these grasses increases forage production and farm income.