Influence of coloured noise on the extinction risk in structured population models     

Mikko Heino  Mireia Sabadell   《Biological conservation》2003,110(3):643-325

We use simple models to compare extinction risk among basic life history types when environmental noise is either uncorrelated (“white”) or positively autocorrelated (“red”). The metric of extinction is probability of extinction in 50 years; variability of noise is scaled such that its expected variance is independent of colour at this time scale. We compare annual, semelparous biennial, iteroparous biennial and perennial life histories. Given an identical equilibrium population size and basic reproductive number, annual life history confers much higher extinction risk than semelparous biennial life history. Iteroparous biennial and perennial life histories have even lower extinction risks. Autocorrelated noise influences the life histories differently: the extinction risk of the annuals decreases with reddening noise, whereas the other life histories show an opposite response. We show that in a previously developed stage-structured population model for the Florida scrub jay Aphelocoma coerulescens ignoring the possibility of red environmental noise might result in much too optimistic assessment on population viability. In conclusion, simplifications of population structure and ignoring red environmental noise in population viability analyses can result in serious biases.  相似文献   

Mapping of urban roadside trees – A case study in the tree register update process in Helsinki City     

Topi Tanhuanpää  Mikko Vastaranta  Ville Kankare  Markus Holopainen  Juha Hyyppä  Hannu Hyyppä  Petteri Alho  Juha Raisio 《Urban Forestry & Urban Greening》2014,13(3):562-570

This case study describes a method for utilizing leaf-off airborne laser scanning (ALS) data for mapping characteristics of urban trees. ALS data were utilized to detect and update all street trees in the tree inventory of the City of Helsinki, Finland. The inventory consists of roughly 20,000 street trees with mean diameter at breast height (DBH) of 24 cm and mean height of 10.6 m. The large number of trees makes the manual updating process very laborious. The automatic mapping procedure presented in this paper detected 88.8% of all trees in the inventory. Tree height was predicted with root mean square error (RMSE) of 1.27 meters and tree DBH with RMSE of 6.9 cm. The presented method provides a practical and cost–effective tool for the mapping of urban tree characteristics. The cost–efficiency was further enhanced because the used ALS data were originally collected for other urban planning purposes.  相似文献   

Optimal multi-product management of stands producing timber and wild berries     

Jari Miina  Timo Pukkala  Mikko Kurttila 《European Journal of Forest Research》2016,135(4):781-794

  相似文献   

Using multi-source data to map and model the predisposition of forests to wind disturbance     

Ninni Saarinen  Mikko Vastaranta  Eija Honkavaara  Michael A. Wulder  Joanne C. White  Paula Litkey 《Scandinavian Journal of Forest Research》2016,31(1):66-79

Natural disturbances such as wind are known to cause threats to ecosystem services as well as sustainable forest ecosystem management. The objective of this research was to better understand and quantify drivers of predisposition to wind disturbance, and to model and map the probability of wind-induced forest disturbances (P_DIS) in order to support forest management planning. To accomplish this, we used open-access airborne light detection and ranging (LiDAR) data as well as multi-source National Forest Inventory (NFI) data to model P_DIS in southern Finland. A strong winter storm occurred in the study area in December 2011. High spatial resolution aerial images, acquired after the disturbance event, were used as reference data. Potential drivers associated with P_DIS were examined using a multivariate logistic regression model. The model based on LiDAR provided good agreement with detected areas susceptible to wind disturbance (73%); however, when LiDAR was combined with multi-source NFI data, the results were more promising: prediction accuracy increased to 81%. The strongest predictors in the model were mean canopy height, mean elevation, and stem volume of the main tree species (Norway spruce and Scots pine). Our results indicate that open-access LiDAR data can be used to model and map the probability of predisposition to wind disturbance, providing spatially detailed, valuable information for planning and mitigation purposes.  相似文献   

Evolutionary impact assessment: accounting for evolutionary consequences of fishing in an ecosystem approach to fisheries management     

Ane T Laugen  Georg H Engelhard  Rebecca Whitlock  Robert Arlinghaus  Dorothy J Dankel  Erin S Dunlop  Anne M Eikeset  Katja Enberg  Christian Jørgensen  Shuichi Matsumura  Sébastien Nusslé  Davnah Urbach  Loїc Baulier  David S Boukal  Bruno Ernande  Fiona D Johnston  Fabian Mollet  Heidi Pardoe  Nina O Therkildsen  Silva Uusi‐Heikkilä  Anssi Vainikka  Mikko Heino  Adriaan D Rijnsdorp  Ulf Dieckmann 《Fish and Fisheries》2014,15(1):65-96

Managing fisheries resources to maintain healthy ecosystems is one of the main goals of the ecosystem approach to fisheries (EAF). While a number of international treaties call for the implementation of EAF, there are still gaps in the underlying methodology. One aspect that has received substantial scientific attention recently is fisheries‐induced evolution (FIE). Increasing evidence indicates that intensive fishing has the potential to exert strong directional selection on life‐history traits, behaviour, physiology, and morphology of exploited fish. Of particular concern is that reversing evolutionary responses to fishing can be much more difficult than reversing demographic or phenotypically plastic responses. Furthermore, like climate change, multiple agents cause FIE, with effects accumulating over time. Consequently, FIE may alter the utility derived from fish stocks, which in turn can modify the monetary value living aquatic resources provide to society. Quantifying and predicting the evolutionary effects of fishing is therefore important for both ecological and economic reasons. An important reason this is not happening is the lack of an appropriate assessment framework. We therefore describe the evolutionary impact assessment (EvoIA) as a structured approach for assessing the evolutionary consequences of fishing and evaluating the predicted evolutionary outcomes of alternative management options. EvoIA can contribute to EAF by clarifying how evolution may alter stock properties and ecological relations, support the precautionary approach to fisheries management by addressing a previously overlooked source of uncertainty and risk, and thus contribute to sustainable fisheries.  相似文献   

Influence of fertilization, mulch color, early forcing, fruit order, planting date, shading, growing Environment, and genotype on the contents of selected phenolics in strawberry (Fragaria x ananassa Duch.) fruits     

Anttonen MJ  Hoppula KI  Nestby R  Verheul MJ  Karjalainen RO 《Journal of agricultural and food chemistry》2006,54(7):2614-2620

The influence of agricultural practices (fertilization, mulch color, early forcing, and planting date), environment (light and growing area), cultivar, and fruit order on the selected phenolic content and antioxidant activity in strawberry (Fragaria x ananassa Duch.) fruits was studied. Three different levels of fertilization were given to plants in the fertilization experiment. The lowest fertilization level increased the contents of flavonols and ellagic acid from 19 to 57%. Between cultivars, up to 4-fold differences were found in the flavonol content, and it also varied according to growing environment. Planting date in glasshouse production was important for the phenolic content, and a statistically significant interaction was found between planting date and fruit order. Fruit order caused at highest 1.5-2.0-fold differences in the contents of phenolics. Interestingly, compared with other phenolics, anthocyanins were affected differently by many factors. Thus, the findings show that minor cultivation changes can increase the content of phenolics, especially in under-glass production where conditions can be easily manipulated.  相似文献   

Identification of boreal forest stands with high herbaceous plant diversity using airborne laser scanning     

Mikko Vehmas  Kalle Eerikäinen  Jussi Peuhkurinen  Petteri Packalén  Matti Maltamo 《Forest Ecology and Management》2009

Boreal forest stands with high herbaceous plant species diversity have been found to be one of the main habitats for many endangered species, but the locations and sizes of these herb-rich forest stands are not well known in many areas. Better identification of the stands could improve both their conservation and management. A new approach is proposed here for locating the mature herb-rich forest stands using airborne laser scanner (ALS) data and logistic regression, or the k-NN classifier. We show that ALS technology is capable of distinguishing the ecologically important herb-rich forests from those growing on less fertile site types, mainly on the basis of unique but quantifiable crown structure and vertical profile that characterise forests on high fertility sites. The study site, Koli National Park, is located on the border of the southern and middle boreal vegetation zones in Finland, and includes 63 herb-rich forest stands of varying sizes. The model and test data comprised 274 forest stands belonging to five forest site types varying from very fertile to poor. The best overall classification accuracy achieved with the k-NN method was 88.9%, the herb-rich forests being classified correctly in 65.0% of cases and the other forest site types in 95.7%. The best overall classification accuracy achieved with logistic regression was 85.6%, being 55.0% for the herb-rich forests and 94.3% for the other forest site types. Both methods demonstrated promising potential for separating herb-rich forests from other forest site types, although slightly better results were obtained with the non-parametric k-NN method, which was capable of utilising a higher number of explanatory variables. It is concluded that ALS-based data analysis techniques are applicable to the detection of mature boreal herb-rich forests in large-scale forest inventories.  相似文献   

Do environmental diversity approaches lead to improved site selection? A comparison with the multi-species approach   总被引：2，自引：0，他引：2  

Artti Juutinen  Mikko Mnkknen  Markku Ollikainen 《Forest Ecology and Management》2008,255(11):3750-3757

This paper suggests a new approach to select conservation areas cost-effectively according to the concept of complementarity and representation of focal natural features. The suggested environmental diversity (ED) site selection model maximizes ecological diversity, measured via ordination of the chosen taxa communities. Given their fundamental role in ecosystem functioning, vascular plants are chosen as the indicator taxa. We test the ED indicator model by contrasting it to the conventional site selection indicator (MS model), which maximizes the representation of species number in the indicator taxa. We demonstrate that the ED model is more cost-effective than the MS model. More importantly, while the ED selection is operative over the whole range of species, the MS selection does not work beyond the range of species, where all vascular plants become protected. Beyond that point MS indicator model cannot guide conservation efforts, which is a serious drawback. The ED model outperforms MS model also in terms of habitat conservation and taxonomic diversity. Thus, it provides an interesting selection framework for biodiversity.  相似文献   

Trait‐related variation in the reproductive characteristics of female pikeperch (Sander lucioperca)          下载免费PDF全文

M. Olin  A. Vainikka  T. Roikonen  J. Ruuhijärvi  H. Huuskonen  M. Kotakorpi  S. Vesala  P. Ala‐Opas  J. Tiainen  L. Nurminen  H. Lehtonen 《Fisheries Management and Ecology》2018,25(3):220-232

Maternal characteristics typically affect the recruitment of an exploited fish population. The size and age at maturity, as well as the effects of maternal traits on relative fecundity and egg dry weight, were studied in six exploited pikeperch populations in Finnish lakes. The among‐lake variation in the maternal characteristics was substantial. The estimated total length at maturity (L₁₀, L₅₀, L₉₀) varied between 318–444, 403–423 and 444–527 mm, respectively, largely depending on the average growth rate and body condition of pikeperch. The estimated L₅₀ was generally close to the recently imposed national minimum size limit (42 cm). The estimated age at maturity (A₅₀) ranged from 4.2 to 6.9 year. Both relative fecundity and egg dry weight significantly increased with female size and age, indicating size‐ and age‐dependent maternal effects on egg characteristics and quantity, and emphasising the importance of large individuals for reproduction. The observed among‐population differences in the size‐dependent maternal influences highlight the need for stock‐specific management of pikeperch fisheries. The conservation of large females should be promoted to increase recruitment and reduce its variability.  相似文献   

Vertical and horizontal distribution of ascending Atlantic salmon in power plant tailrace channels          下载免费PDF全文

Tapio Sutela  Panu Orell  Ari Huusko  Mikko Jaukkuri  Riina Huusko  Aki Mäki‐Petäys  Jaakko Erkinaro 《Fisheries Management and Ecology》2018,25(4):267-274

Three‐dimensional distribution of adult upstream‐migrating Atlantic salmon, Salmo salar L., was studied in three power plant tailrace channels on the large, regulated River Kemijoki in northern Finland using novel pressure sensor radio telemetry. The salmon swam mostly at depths of 1–4 m below the surface, with the salmon‐specific averages ranging from 1.3 to 6.4 m. When approaching a power plant, no change in swimming depth was observed. The horizontal locations of salmon in the two regularly shaped tailrace channels peaked at 5–10 m distance from the shoreline and showed a positively skewed distribution with a tail towards the central part of the tailrace. A graphical presentation of salmon locations in the tailrace channel and data on swimming depth and distance from the shoreline may prove useful in determining the location and design of a fishway entrance and in dimensioning attraction flow.  相似文献