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11.
The landscape matrix modifies the effect of habitat fragmentation in grassland butterflies 总被引:1,自引:0,他引:1
Erik ?ckinger Karl-Olof Bergman Markus Franzén Tomá? Kadlec Jochen Krauss Mikko Kuussaari Juha P?yry Henrik G. Smith Ingolf Steffan-Dewenter Riccardo Bommarco 《Landscape Ecology》2012,27(1):121-131
The landscape matrix is suggested to influence the effect of habitat fragmentation on species richness, but the generality
of this prediction has not been tested. Here, we used data from 10 independent studies on butterfly species richness, where
the matrix surrounding grassland patches was dominated by either forest or arable land to test if matrix land use influenced
the response of species richness to patch area and connectivity. To account for the possibility that some of the observed
species use the matrix as their main or complementary habitat, we analysed the effects on total species richness and on the
richness of grassland specialist and non-specialist (generalists and specialists on other habitat types) butterflies separately.
Specialists and non-specialists were defined separately for each dataset. Total species richness and the richness of grassland
specialist butterflies were positively related to patch area and forest cover in the matrix, and negatively to patch isolation.
The strength of the species-area relationship was modified by matrix land use and had a slope that decreased with increasing
forest cover in the matrix. Potential mechanisms for the weaker effect of grassland fragmentation in forest-dominated landscapes
are (1) that the forest matrix is more heterogeneous and contains more resources, (2) that small grassland patches in a matrix
dominated by arable land suffer more from negative edge effects or (3) that the arable matrix constitutes a stronger barrier
to dispersal between populations. Regardless of the mechanisms, our results show that there are general effects of matrix
land use across landscapes and regions, and that landscape management that increases matrix quality can be a complement to
habitat restoration and re-creation in fragmented landscapes. 相似文献
12.
针对面向大规模定制的家具模块编码与配置技术进行了探讨与分析,并以芬兰某企业的模块配置器为例,阐述其配置原理与流程,以期为国内家具企业实现从大规模生产向大规模定制的模式转换,提供路径指导与技术支持. 相似文献
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14.
Peltoniemi M Pulkkinen M Kolari P Duursma RA Montagnani L Wharton S Lagergren F Takagi K Verbeeck H Christensen T Vesala T Falk M Loustau D Mäkelä A 《Tree physiology》2012,32(2):200-218
The maximum light use efficiency (LUE?=?gross primary production (GPP)/absorbed photosynthetic photon flux density (aPPFD)) of plant canopies has been reported to vary spatially and some of this variation has previously been attributed to plant species differences. The canopy nitrogen concentration [N] can potentially explain some of this spatial variation. However, the current paradigm of the N-effect on photosynthesis is largely based on the relationship between photosynthetic capacity (A(max)) and [N], i.e., the effects of [N] on photosynthesis rates appear under high PPFD. A maximum LUE-[N] relationship, if it existed, would influence photosynthesis in the whole range of PPFD. We estimated maximum LUE for 14 eddy-covariance forest sites, examined its [N] dependency and investigated how the [N]-maximum LUE dependency could be incorporated into a GPP model. In the model, maximum LUE corresponds to LUE under optimal environmental conditions before light saturation takes place (the slope of GPP vs. PPFD under low PPFD). Maximum LUE was higher in deciduous/mixed than in coniferous sites, and correlated significantly with canopy mean [N]. Correlations between maximum LUE and canopy [N] existed regardless of daily PPFD, although we expected the correlation to disappear under low PPFD when LUE was also highest. Despite these correlations, including [N] in the model of GPP only marginally decreased the root mean squared error. Our results suggest that maximum LUE correlates linearly with canopy [N], but that a larger body of data is required before we can include this relationship into a GPP model. Gross primary production will therefore positively correlate with [N] already at low PPFD, and not only at high PPFD as is suggested by the prevailing paradigm of leaf-level A(max)-[N] relationships. This finding has consequences for modelling GPP driven by temporal changes or spatial variation in canopy [N]. 相似文献
15.
R.Gayman Helman DVM PhD DipACVP Olin K. Balch DVM MS PhD Connie Budd BS 《Journal of Equine Veterinary Science》2002,22(1)
The shape of equine hooves is difficult to measure and quantify. Scientific research on the effects of hoof conformation on normal and abnormal locomotion often requires precise characterization of hoof conformation. This technique produces accurate, life-size, permanent models of the hoof quickly and inexpensively from dental plastic powder and dental plaster. 相似文献
16.
Empirical forest owner classifications typically distinguish groups based on owners’ behaviour or motivations. Typologies are used to inform forest and environmental policies and market-based service provision. However, single typologies may be weak in discerning owner groups that would bring new insights for policymakers or service providers. The present study aims to put together two previously documented owner classification frameworks to form and analyse customer segments for decision-support services. The first grouping is based on owners’ objectives for forest ownership, while the second grouping focuses on owners’ decision-making styles. These two typologies deal with subjects of interest and motivations for communication, respectively. The study uses a subsample of the Finnish Forest Owner 2010 survey data, collected in 2009 (n = 2,106). Via cross-tabulation of the two groupings, the four largest and potentially most interesting combined owner groups are discerned: multiobjective learners (13 %), multiobjective thinkers (9 %), learning recreationists (8 %) and learning investors (7 %), while the other 16 combined groups each account for less than 6 % of owners. The result thus reveals the need for learning-oriented services for three differing principal subjects of interest as well as multiobjective services for deliberate thinkers, i.e. comparative information about forest management alternatives. The message for policymakers and service providers is that the majority of forest owners may be served with educative interactive services. Learning-oriented indifferent owners need special services to recognize their latent goals. Delegators need ready-made services for outsourced decision making and self-reliant owners need information packages of varying contents. Combinations of groups prove feasible for producing policy advice. 相似文献
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18.
Olli Arjamaa Olli Vuolteenaho Elina Kivi Mikko Nikinmaa 《Fish physiology and biochemistry》2014,40(1):67-73
Our aim was to study the effects of hypoxia on the release of salmon cardiac peptide (sCP) from an isolated heart ventricle of trout during a constant mechanical load. Trout heart ventricles were studied in vitro. The ventricle was placed in an organ bath at 12 °C in which a constant mechanical load could be imposed on the ventricle while buffer solution was circulating. Ventricles were field-stimulated with a supramaximal voltage pulse at a rate of about 0.3 s?1. Samples of 1 ml were collected at an interval of 10 min for 200 min from the organ bath and assessed with a radioimmunoassay for sCP. After a control period of 20 min, ventricles were exposed to hypoxia produced with N2 gassing (n = 9) or to hypoxia with 20 mM BDM, a nonselective myosin ATPase inhibitor locking cross-bridges in a pre-power-stroke state inhibiting force production with normal electrical activity (n = 10). In this model and setup, hypoxia stimulated the release of sCP, but the interindividual variation in the response was large. At the end of hypoxia exposure, the concentration of sCP in the organ bath was about sixfold higher than at the start of the exposure (P < 0.05, one-way ANOVA for repeated measurements, followed by Dunnett’s multiple comparison test). When BDM was introduced into the bath, the ventricle still secreted sCP but the hypoxic response was smaller than in the experiments without BDM. In the trout heart ventricle, there is a hypoxia-sensitive component in the release mechanism of sCP which is independent of contraction. 相似文献
19.
Samuli Junttila Mikko Vastaranta Jarno Hämäläinen Petri Latva-käyrä Markus Holopainen Rocío Hernández Clemente 《Scandinavian Journal of Forest Research》2017,32(2):154-165
The effect of forest structure and health on the relative surface temperature captured by airborne thermal imagery was investigated in Norway Spruce-dominated stands in Southern Finland. Airborne thermal imagery, airborne scanning light detection and ranging (LiDAR) data and 92 field-measured sample plots were acquired at the area of interest. The surface temperature correlated most negatively with the logarithm of stem volume, Lorey’s height and the logarithm of basal area at a resolution of 254?m2 (9?m radius). LiDAR-derived metrics: the standard deviations of the canopy heights, canopy height (upper percentiles and maximum height) and canopy cover percentage were most strongly negatively correlated with the surface temperature. Although forest structure has an effect on the detected surface temperature, higher temperatures were detected in severely defoliated canopies and the difference was statistically significant. We also found that the surface temperature differences between the segmented canopy and the entire plot were greater in the defoliated plots, indicating that thermal images may also provide some additional information for classifying forests health status. Based on our results, the effects of forest structure on the surface temperature captured by airborne thermal imagery should be taken into account when developing forest health mapping applications using thermal imagery. 相似文献
20.
Markus Holopainen Antti Mäkinen Jussi Rasinmäki Juha Hyyppä Hannu Hyyppä Harri Kaartinen Risto Viitala Mikko Vastaranta Annika Kangas 《European Journal of Forest Research》2010,129(5):899-907
The objective was to compare tree-level airborne laser-scanning (ALS) data accuracy with standwise estimation data accuracy
as input data for forest planning, using tree- and stand-level simulators. The influence of the input data accuracy was studied
with respect to (1) timing of the next thinning or clear-cutting and (2) the relative variation in the predicted income of
the next logging expressed as the net present value (NPV). The timing and predicted NPV of thinning and clear-cutting operations
were considered separately. The research was based on Monte Carlo simulations carried out with the tree- and stand-level simulators
using a simulation and optimisation (SIMO) framework. The simulations used treewise measurements taken on 270 circular plots
measured at the Evo Field Station, Finland, as input data. Deviations in the tree data measured were generated according to
the mean standard errors found in standwise field estimation and tree-level ALS. The accuracy factors of ALS individual tree
detection were based on the EUROSDR/ISPRS Tree Extraction Project. The results show that input data accuracy significantly
affects both the timing and relative NPV of loggings. Tree-level ALS produces more accurate simulation results than standwise
estimation with the error levels assumed. Diameter-based characteristics are the most important input data in all simulations.
Accurate tree height estimates cannot be fully utilised in current simulators. 相似文献