研究了垂穗披碱草(E lym us nutans)在不同光照强度、不同土壤养分和不同密度下的生长和繁殖特性。结果表明增加施肥量使垂穗披碱草的新增分蘖百分数、分蘖大小、营养繁殖和有性繁殖输出及其效力明显增加,贮藏生长效力相对减少;提高光...研究了垂穗披碱草(E lym us nutans)在不同光照强度、不同土壤养分和不同密度下的生长和繁殖特性。结果表明增加施肥量使垂穗披碱草的新增分蘖百分数、分蘖大小、营养繁殖和有性繁殖输出及其效力明显增加,贮藏生长效力相对减少;提高光照强度增加新增分蘖百分数、营养繁殖输出、有性繁殖输出和效力以及贮藏生长效力,减少营养繁殖效力;低密度下新增分蘖百分数、分蘖大小和营养繁殖效力显著增加,高密度下营养繁殖输出、有性繁殖输出和效力以及贮藏生长效力较高。在高施肥×高光照、高施肥×高密度和高光照×高密度处理下,植物有性繁殖输出和营养繁殖输出显著高于其它处理。低密度条件下新增分蘖百分数较高,高密度条件下有性繁殖效力较高。三因子互作对性状无显著作用。营养繁殖效力与有性繁殖效力无显著相关,这两者与贮藏生长效力为负相关。以上结果说明丰富的资源(高施肥、高光照)有利于植物生长和繁殖,种内竞争水平对体内的资源分配会产生很大影响。这些特性既与环境因子有关,又与植物性状间的内在联系有关,共同决定该种群在群落中的动态和稳定性。展开更多
The climate,mainly the water availability and temperature,drives the renewal of biomass inseasonal forest ecosystem,and the greenness and leaf area of its canopy are responsive climate variations.This study verified ...The climate,mainly the water availability and temperature,drives the renewal of biomass inseasonal forest ecosystem,and the greenness and leaf area of its canopy are responsive climate variations.This study verified models to explain the phenomenon of leaf production and deciduousness by time,with LAI（Leaf Area Index）,NDVI（Normalized Difference VegetationIndex）and climate variables,on period 2011-2016. The data were obtained in satellite images and in plots installed at forestmonitoring sites,visited monthly.The analysis incorporated the water balance.Three equations were compared,two alreadypublished and the equation that was adjusted in this work.The model was improved and validated with new variables and data.It is possible to estimate the fall and renew of leaves biomass in semideciduous forests with reasonable precision.展开更多
Environmental warming places physiological constraints on organisms, which may be mitigated by their feeding behavior. Theory predicts that consumers should increase their feeding selectivity for more energetically va...Environmental warming places physiological constraints on organisms, which may be mitigated by their feeding behavior. Theory predicts that consumers should increase their feeding selectivity for more energetically valuable resources in warmer environments to offset the disproportionate increase in metabolic demand relative to ingestion rate. This may also result in a change in feeding strategy or a shift towards a more specialist diet. This study used a natural warming experiment to investigate temperature effects on the feeding selectivity of three freshwater invertebrate grazers： the snail Radix balthica, the blackfly larva Simulium aureum, and the midgefly larva Eukiefferiella minor. Chesson＇s Selectivity Index was used to compare the proportional abundance of diatom species in the guts of each invertebrate species with corresponding rock biofilms sampled from streams of different tem- perature. The snails became more selective in warmer streams, choosing high profile epilithic diatoms over other guilds and feeding on a lower diversity of diatom species. The blackfly larvae appeared to switch from active collector gathering of sessile high profile diatoms to more passive filter feeding of motile diatoms in warmer streams. No changes in selectivity were observed for the midgefly larvae, whose diet was representative of resource availability in the environment. These results suggest that key primary consumers in freshwater streams, which constitute a major portion of invertebrate biomass, can change their feeding behavior in warmer waters in a range of different ways. These patterns could potentially lead to fundamental changes in the flow of energy through freshwater food webs.展开更多
文摘研究了垂穗披碱草(E lym us nutans)在不同光照强度、不同土壤养分和不同密度下的生长和繁殖特性。结果表明增加施肥量使垂穗披碱草的新增分蘖百分数、分蘖大小、营养繁殖和有性繁殖输出及其效力明显增加,贮藏生长效力相对减少;提高光照强度增加新增分蘖百分数、营养繁殖输出、有性繁殖输出和效力以及贮藏生长效力,减少营养繁殖效力;低密度下新增分蘖百分数、分蘖大小和营养繁殖效力显著增加,高密度下营养繁殖输出、有性繁殖输出和效力以及贮藏生长效力较高。在高施肥×高光照、高施肥×高密度和高光照×高密度处理下,植物有性繁殖输出和营养繁殖输出显著高于其它处理。低密度条件下新增分蘖百分数较高,高密度条件下有性繁殖效力较高。三因子互作对性状无显著作用。营养繁殖效力与有性繁殖效力无显著相关,这两者与贮藏生长效力为负相关。以上结果说明丰富的资源(高施肥、高光照)有利于植物生长和繁殖,种内竞争水平对体内的资源分配会产生很大影响。这些特性既与环境因子有关,又与植物性状间的内在联系有关,共同决定该种群在群落中的动态和稳定性。
文摘The climate,mainly the water availability and temperature,drives the renewal of biomass inseasonal forest ecosystem,and the greenness and leaf area of its canopy are responsive climate variations.This study verified models to explain the phenomenon of leaf production and deciduousness by time,with LAI（Leaf Area Index）,NDVI（Normalized Difference VegetationIndex）and climate variables,on period 2011-2016. The data were obtained in satellite images and in plots installed at forestmonitoring sites,visited monthly.The analysis incorporated the water balance.Three equations were compared,two alreadypublished and the equation that was adjusted in this work.The model was improved and validated with new variables and data.It is possible to estimate the fall and renew of leaves biomass in semideciduous forests with reasonable precision.
文摘Environmental warming places physiological constraints on organisms, which may be mitigated by their feeding behavior. Theory predicts that consumers should increase their feeding selectivity for more energetically valuable resources in warmer environments to offset the disproportionate increase in metabolic demand relative to ingestion rate. This may also result in a change in feeding strategy or a shift towards a more specialist diet. This study used a natural warming experiment to investigate temperature effects on the feeding selectivity of three freshwater invertebrate grazers： the snail Radix balthica, the blackfly larva Simulium aureum, and the midgefly larva Eukiefferiella minor. Chesson＇s Selectivity Index was used to compare the proportional abundance of diatom species in the guts of each invertebrate species with corresponding rock biofilms sampled from streams of different tem- perature. The snails became more selective in warmer streams, choosing high profile epilithic diatoms over other guilds and feeding on a lower diversity of diatom species. The blackfly larvae appeared to switch from active collector gathering of sessile high profile diatoms to more passive filter feeding of motile diatoms in warmer streams. No changes in selectivity were observed for the midgefly larvae, whose diet was representative of resource availability in the environment. These results suggest that key primary consumers in freshwater streams, which constitute a major portion of invertebrate biomass, can change their feeding behavior in warmer waters in a range of different ways. These patterns could potentially lead to fundamental changes in the flow of energy through freshwater food webs.
