Time-traveling larvae ensure survival in small, synchronously fluctuating populations

Population structure is an important aspect of patchily distributed organisms. Small local populations, large temporal fluctuations, synchronized dynamics, and low migration rates should all lead to lowered rates of patch occupancy and increased extinction risks. These effects can, however, be counteracted if there is a pool of hidden, dormant individuals bridging unfavorable periods. Prolonged diapause-a dormancy that extends over two or more years-provides such a temporal bridge among insects, but its role in structuring patchy populations is poorly known. Based upon a long-term study, we explore the landscape scale population structure of a galling insect, the larva of which has an unusually long diapause spent hidden in the soil. Gall populations in patches fluctuated synchronously in a long wave with a tenfold amplitude. Abundances were very low with a median of less than twenty galls per patch. Although only a third of the patches had galls in all years, local populations persisted thanks to the pool of diapausing larvae. Colonizations of two new plant patches were very slow. The combination of small, synchronously fluctuating gall populations and high occupancy rates can be maintained because of the very low extinction rates imposed by the time-traveling diapausing larvae

Operationalisation of ecological compensation - Obstacles and ways forward

Ecological compensation (EC) has been proposed as an important tool for stopping the loss of biodiversity and natural values. However, there are few studies on its actual operationalisation and there is high uncertainty about how it should be designed and implemented to be an effective way of performing nature conservation. In this study we focus on ecological compensation in Sweden, a country where it is in the process of being implemented more broadly. Using interviews and a workshop we investigate how the work with the implementation is carried out and what challenges exist. The results show that implementation of EC is at an early stage of development and there are many practical obstacles, linked to both legislation and routines in the planning processes. There is a lack of holistic perspective and large-scale thinking, a quite strong focus on a small number of individual species, and an overall attitude that anything is better than nothing, all of which can have negative consequences for biodiversity conservation overall. Based on the results we discuss the need for better integration of EC into the entire decision-making process and for a holistic approach to preservation of biodiversity and ecosystem services, by increasing the focus on landscape perspective and considering delays in compensation outcomes. There is also a need for a national level standard for EC, making good and worse examples of compensation measures available and systematic monitoring of EC projects. Finally, a spatially explicit database to document all EC areas should be introduced both to ensure consistency in protection from future development plans and to enable long-term monitoring of EC outcomes

Substrate specificity among Diptera in decaying bioenergy wood: can they be conserved by the same measures as are currently applied to beetles?

Although threatened by forestry, our knowledge concerning saproxylic insects is strongly biased towards well-known orders, mainly beetles (Coleoptera). The beetles have, therefore, formed the basis on which conservation measures of other groups have been formulated. Despite being more species-rich, the Diptera have been rather neglected. Moreover, our limited knowledge of the Diptera suggests that their demands on the dead wood substrate differ markedly from that of coleopterans. We tested if this is true by comparing the substrate requirements of dipteran and coleopteran species by analysing the affinities of species assemblages for logging residues differing in age, size, and tree species. Insects were reared out from the same samples of bioenergy wood from clear-cuts in Sweden. 15 species of Brachyceran flies were compared with 56 species of Coleoptera. We found the average level of specialisation to be similar between the two groups, but the dipterans had (contrary to the expectations) a higher proportion of specialists. Affinities for differently aged wood were similar. More dipterans than beetles were associated with the coarsest wood (diameter 9 cm-15 cm). More dipterans than beetles tended to be associated with aspen (Populus tremula), while Coleoptera tended to be more associated than Diptera with oak (Quercus) and spruce (Picea abies). We conclude that most recommendations for conserving the saproxylic beetle fauna also seem to benefit dipterans, but that the dipterans might be even more sensitive to which qualities of the wood that is preserved. The high conservation value of aspen is already recognised and our results for dipterans strengthen this. The high incidence of many dipteran species in logging residues suggests that many dipterans use sun-exposed environments

Trade and production of plants and plant products in Sweden

This report summarises the quantity of plants and plant-related products that are traded into Sweden, which serve as pathways of entry for plant pests. Furthermore, the economic value of plants and plant products is presented in terms of production value as well as the value of trade from Sweden.In total, the volume of plants and plant material traded into Sweden was on average nearly 13 million tons per year. Of this, by far the largest part was various types of wood products, 11.3 million tons, followed by fruit and other types of plant based food, 0.7 million tons. Propagation material for different production systems was in terms of weight a small proportion of the total amount of traded plant goods into Sweden, reaching only about 43 thousand tons, it is however a rather large source of the living plant material traded. For example, an annual average of 49 million seedlings of forest trees were traded into Sweden each year.The volume of plants and plant material traded from Sweden totaled more than 9 million tons, with an annual yearly value of over 30 billion SEK. Hence, the trade from the country was less than into the country. The trade both into and from Sweden was dominated by wood products, with a yearly average of 11.2 and 8.2 million tons respectively.The total annual economic value of plants and plant products produced in Sweden was 57 billion SEK, which was 1.7 times the value of the trade of plants and plant products from Sweden. A great majority of the production value is associated with forest trees, 29 billion SEK, and arable plants, 22 billion SEK.The economic value of vegetables and ornamentals and other plants produced in horticulture was approximately 2.5 billion SEK each. The estimated annual value of park- and street trees in Swedish cities, based on the cost of replacing them after 80 years, was 1.3 billion SEK. Fruits and berries constitute a minor part of plants and plant products produced, 966 million SEK.In conclusion the amounts of trade as wells as the economic value of plants and plant products quantified in this survey provides valuable information for determining pest specific risks for introduction as well as the potential impact if a species becomes established. The compilation of data also provides support for identifying potential pathways for plant pests

Mapping and analysis of transport of sawn goods at NWP AB

Detta examensarbete har utförts hos Norrskog Wood Products AB (NWP AB) som omfattar fyra sågverk och tre hyvlerier i mellannorrland. NWP AB bildades 2004 när Skogsägare-föreningen Norrskog köpte Camforegruppen i Jämtland och fusionerade den med sitt tidigare helägda sågverk SAEF AB (Östavallsågen). Vid årsskiftet 05/06 förvärvades det tredje hyvleriet som ligger i Forsa utanför Hudiksvall. I dagsläget när företaget fortfarande är relativt ungt sker det mesta av transportplanering och fraktbokningen vid varje enhet och man gör som man tidigare har gjort. Syftet med examens-arbetet är att för en bestämd period, 2005-01-01 till 2005-05-31, kartlägga transporter och kostnader från industri till kund för hela NWP AB. Det ska också svara på hur deras logistiksystem ser ut idag samt vilka förändringar de kan göra för att förbättra det. Kartläggningen av transporterna visade på att man kan slå samman vissa postnummerområden till grupper (sex stycken) som tar emot större volymer varje månad. Dessa områden kan man sedan erbjudas till en eller flera speditörer att hantera och ansvara för. Detta skulle kunna tvinga ned priset exempel genom ett budgivningsförfarande. Undersökningen visade också att det är lönsamt att nyttja tågtransporter över längre sträckor inom Sverige. Detta är i och för sig känt sedan tidigare men i denna undersökning räknades det fram en ungefärlig brytpunkt för de enheter som använder både tåg och lastbils¬transporter inom Sverige. Det är vanligt i branschen att transportkostnaden per kilometer för frakten delas upp i fast grundkostnad, där bland annat löner och maskinkostnader ingår, samt ett rörligt procentuellt påslag som är beroende av bland annat fluktuationer på bränslepriset. Men det går även till viss del förhandla om vad som ska ingå i det fasta grundpriset. Till områden dit transportkostnaden per kilometer är hög bör man försöka hålla ned eller undvika procentuella ökningar av priset. Detta eftersom ökningen i kronor blir så stor för varje procent som läggs på. Det kan då vara värt att välja en speditör som har ett högre fast pris men som i gengäld inte har så stort utrymme för de svårförutsägbara rörliga kostnaderna. För övriga destinationer med relativt låga totala kilometerkostnader är det viktigare att ha ett lågt grundpris. Man kan då istället tillåta större procentuella variationer eftersom påslaget på priset inte har lika stor inverkan räknat i kronor på den totala kostnaden. En bra kommunikation mellan säljaren och utlastningsansvarig är mycket viktig för att sälja¬ren ska få ett så korrekt fraktpris som möjligt när han ska göra affären. Risken är annars att säljare erhåller bristfälliga underlag inför uppskattningen av fraktkostnaden. Det kan medföra att säljaren uppskattar ett för lågt pris på frakten i sin iver att erbjuda kunden ett bra pris vilket i slutändan när frakten ska betalas drar ned den vinst som säljaren räknade med. För att öka kommunikationen mellan säljare och utlastningsansvariga bör det upprättas ett gemensamt fraktdokument för hela NWP AB. I detta dokument kan alla berörda gå in och se vad fraktkostnaden är för de olika postnummerområdena i alla länder med olika speditörer och fraktsätt. Detta dokument bör uppdateras kontinuerligt med alla förändringar som sker med till exempel förändrade villkor och nya speditörer.This master thesis has been carried out at Norrskog Wood Products AB (NWP AB), a company with four sawmills and three planing mills in the middle of Sweden. NWP AB is the result of a merger between the Camfore group and the forest owners’ association Norrskog’s industry SEAF AB (Östavallsågen). Today, when the company still is rather new, most of the transport planning and booking of transports are done at every unit separately as they have done before the merger. The purpose of this thesis is to, for the time period ranging from 2005-01-01 to 2005-05-31, analyse the transports and costs from NWP AB to its customers. It shall also answer how their logistic system functions today and what changes can be done to improve it. Analysis of the transports shows that six post-code-area clusters receive most of the sold volume. Exclusivity of transports to these clusters can be offered to transporting companies in exchange for a beneficial offering on service/price for transports from their side. The transportation costs of NWP AB will then hopefully be lowered by biddings among the potential contractors. The study also showed that it is profitable to transport the goods by train instead of truck for longer distances. This is already known but in this paper the breaking point in distance between train and truck is roughly calculated for the specific conditions that apply for transport in Sweden from NWP AB. It is common to divide the cost of transportation per kilometre in a fixed basic cost, including, among other, costs for salaries and the cost for the truck. The other part is a variable added cost, calculated as percent, that mostly fluctuates in accordance with the price of fuel. In most cases it is possible to negotiate about what is included in the fixed basic cost. To areas were the transport cost per kilometre is high it is well advised to avoid an increased cost by percent of price. I.e. because the increase in SEK will become so high for each percent that is added to the basic cost. It might then become important to choose a transport company that has a higher fixed basic cost but will not have so large indeterminable variable cost. For the other destinations with a relatively low transport cost per kilometre it is more important to have a low fixed basic cost. It is even possible to allow a greater fluctuation in the variable added cost because it will not have the same impact on the total cost. The contact between sales and freight personnel is of great importance for providing the most accurate estimates possible for the sellers’ calculation of the transport price. The seller takes a risk when he has poor estimates for the transport costs. In the long run it might mean that the seller will set too low transport cost in the deal. To increase the communication between sales and freight personnel a common freight document should be designed for all business units of NWP AB. In this document all parties in NWP AB involved in decisions regarding logistics or sales of produced goods should be able to see what the transport costs are. It should also show the destinations in every country with the different transportation companies. It should be continuously updated with all changes that appear e.g. change of conditions and addition of new transportation companies

Co-transplantation of Human Embryonic Stem Cell-derived Neural Progenitors and Schwann Cells in a Rat Spinal Cord Contusion Injury Model Elicits a Distinct Neurogenesis and Functional Recovery

Co-transplantation of neural progenitors (NPs) with Schwann cells (SCs) might be a way to overcome low rate of neuronal differentiation of NPs following transplantation in spinal cord injury (SCI) and the improvement of locomotor recovery. In this study, we initially generated NPs from human embryonic stem cells (hESCs) and investigated their potential for neuronal differentiation and functional recovery when co-cultured with SCs in vitro and co-transplanted in a rat acute model of contused SCI. Co-cultivation results revealed that the presence of SCs provided a consistent status for hESC-NPs and recharged their neural differentiation toward a predominantly neuronal fate. Following transplantation, a significant functional recovery was observed in all engrafted groups (NPs, SCs, NPs+SCs) relative to the vehicle and control groups. We also observed that animals receiving co-transplants established a better state as assessed with the BBB functional test. Immunohistofluorescence evaluation five weeks after transplantation showed invigorated neuronal differentiation and limited proliferation in the co-transplanted group when compared to the individual hESC-NPs grafted group. These findings have demonstrated that the co-transplantation of SCs with hESC-NPs could offer a synergistic effect, promoting neuronal differentiation and functional recovery

Traits or species – space or environment

How communities are structured and the processes shaping species composition are among the basic questions in ecology. Knowledge about these processes is essential to predict changes in community composition in response to changes in for example climate or land use practices. Soil communities are considered to be both remarkably species-rich and to have many generalist species with seemingly similar niche requirements. Soil fauna composition shows a large variation even at small spatial scales and both local environment and spatial configuration of habitats are regarded as important forces shaping the community composition. In this thesis, I examine the factors influencing small-scale community composition of springtails (Collembola) in two habitats, a variable and dynamic salt marsh and a more stable mature pine forest. The functional traits of species determine both their responses to the environment and their effects on ecosystem processes. The current knowledge on environment - species - traits relationship is limited in spite of its potential importance for ecosystem function. I show that by combining perspectives from two closely linked theoretical frameworks – metacommunity ecology and community assembly theory – we get a better understanding of the important ecological factors operating in this system. I found that the factors influencing community composition was context dependent, but in a predictable way. In the environmentally variable habitat, salt marsh, with spatial and temporal heterogeneity, there was evidence of strong environmental filtering. Small-scale topography was the strongest predictor of community composition, likely due to disturbances restricting where habitat-generalists can persist. In contrast, in the more stable habitat, mature pine forest, environmental filtering appeared weaker and biotic interactions seemed to have a stronger impact. Coexisting species were more similar in traits related to resource utilisation and sensory ability than expected, and variation in species composition was explained mainly by spatial factors like the distance between samples, i.e. each local community seemed to depend on the composition of the surrounding communities

A gaping hole in boreal conservation research: Effects of size and aggregation of conservation areas on species diversity at the landscape scale

Area-based conservation measures are the main approach to preserve forest biodiversity. However, there is no common view on the best strategy in relation to spatial aggregation of conservation areas, for a given total area preserved. We conducted a systematic literature review to evaluate the effect of mean patch size and aggregation of conservation areas on landscape-scale biodiversity in boreal forest. Our main objectives were to find empirical evidence regarding whether few large or several small conservation areas protect more biodiversity and investigate how the spatial aggregation of conservation areas affects biodiversity. We searched specifically for studies comparing biodiversity across many small vs. few large and dispersed vs. aggregated conservation areas, controlling for total area protected. Although our initial search resulted in a large number of articles, not a single study assessed landscape-scale biodiversity in many small vs. few large, or dispersed vs. aggregated conservation areas, of a spatial scale relevant to average-sized or even small nature reserves (i.e. >= 10 ha). We did find 5 studies comparing many small vs. few large conservation patches within clear-cuts, and one study of forest patches within a national park (ca 7 ha). The conservation areas on clear-cuts were patches of retained trees, with the smallest patches being single trees. The effect of patch size on biodiversity varied among studies, mostly indicating neutral effects of patch size. While the results of these studies are relevant to clear-cuts, their relatively small spatial extent (the largest retained patch being 1.2 ha) precludes extrapolation to scales relevant to reserves in boreal forest. Our review exposes an extensive knowledge gap regarding consequences of the sizes of conservation areas on landscape-scale boreal forest biodiversity. Until such information is available, we recommend a combined approach involving both small and large conservation areas in boreal forest

Costs and benefits of seven alternatives for riparian forest buffer management

Stand development in riparian forest buffers was simulated for three forest landscapes in Sweden, using data taken from a sample plot inventory along 38 streams. The objectives were: to quantify the effects on wood production and the economy of management alternatives for buffers; and to evaluate the development of important stand structures for buffer functionality. Buffer widths from 0 to 30 m were analyzed with unmanaged or selective logging as alternatives. Leaving unmanaged buffers resulted in the cost being generally proportional to the area of productive forest land covered by buffers in the landscape. The cost for the widest buffer alternative, 30 m, when left unmanaged, was between 4 and 10% of the total net present value of the entire forest landscape. Allowing selective logging to promote broadleaved trees in the buffer reduced the costs to 1-3% of the net present value. Selective logging increased the volume share of broadleaved trees in the buffer, thus enhancing some of its ecological functions. Unmanaged buffers increased the amount of dead wood more than the alternatives with selective logging. Decisions about buffer zone management must consider the trade-off between economic and environmental benefits, as well as the trade-offs between contrasting environmental goals