Forest edges enhance mate-finding in the European gypsy moth, Lymantria dispar

Understanding movement capabilities of individuals within a landscape is essential to identifying the effects of habitat boundaries on species abundances, ranges, and spread rates. Movement barriers due to habitat fragmentation may reduce mate-finding ability in some species, particularly in heterogeneous landscapes containing low-density populations. This study focuses on the effects of habitat type and edge on mate-finding in an invasive defoliator, the European gypsy moth. Adult European gypsy moth males locate mates by following pheromones released by flightless females. Reduced mate-finding was expected in fields and near forest edges based on geographic variation in invasion rates and pheromone plume dynamics. A male release-recapture experiment using female-baited traps in fields, at forest edges, and in the forest interior showed that mate-finding was highest at forest edges, reduced in fields, and lowest within the forest interior. This suggests that forest edges and moderate habitat fragmentation enhance mate-finding in the gypsy moth

Dispersal and genetic structures in a tropical small mammal, the Bornean tree shrew (Tupaia longipes), in a fragmented landscape along the Kinabatangan River, Sabah, Malaysia

Background Constraints in migratory capabilities, such as the disruption of gene flow and genetic connectivity caused by habitat fragmentation, are known to affect genetic diversity and the long-term persistence of populations. Although negative population trends due to ongoing forest loss are widespread, the consequence of habitat fragmentation on genetic diversity, gene flow and genetic structure has rarely been investigated in Bornean small mammals. To fill this gap in knowledge, we used nuclear and mitochondrial DNA markers to assess genetic diversity, gene flow and the genetic structure in the Bornean tree shrew, Tupaia longipes, that inhabits forest fragments of the Lower Kinabatangan Wildlife Sanctuary, Sabah. Furthermore, we used these markers to assess dispersal regimes in male and female T. longipes. Results In addition to the Kinabatangan River, a known barrier for dispersal in tree shrews, the heterogeneous landscape along the riverbanks affected the genetic structure in this species. Specifically, while in larger connected forest fragments along the northern riverbank genetic connectivity was relatively undisturbed, patterns of genetic differentiation and the distribution of mitochondrial haplotypes in a local scale indicated reduced migration on the strongly fragmented southern riverside. Especially, oil palm plantations seem to negatively affect dispersal in T. longipes. Clear sex-biased dispersal was not detected based on relatedness, assignment tests, and haplotype diversity. Conclusion This study revealed the importance of landscape connectivity to maintain migration and gene flow between fragmented populations, and to ensure the long-term persistence of species in anthropogenically disturbed landscapes

Agricultural aviation research

A compilation of papers, comments, and results is provided during a workshop session. The purpose of the workshop was to review and evaluate the current state of the art of agricultural aviation, to identify and rank potentially productive short and long range research and development areas, and to strengthen communications between research scientists and engineers involved in agricultural research. Approximately 71 individuals actively engaged in agricultural aviation research were invited to participate in the workshop. These were persons familiar with problems related to agricultural aviation and processing expertise which are of value for identifying and proposing beneficial research

The impact of FSC certification on timber tree regeneration and floristic composition in Honduran community forests

Forest certification has been put forward as a means to improve the sustainability of forest management in the tropical countries, where traditional environmental regulation has been inefficient in controlling forest degradation and deforestation. In these countries, the role of communities as managers of the forest resources is rapidly increasing. However, only a fraction of tropical community forests have been certified and little is known about the impacts of certification in these systems. Two areas in Honduras where community-managed forest operations had received FSC certifications were studied. Río Cangrejal represents an area with a longer history of use, whereas Copén is a more recent forest operation. Ecological sustainability was assessed through comparing timber tree regeneration and floristic composition between certified, conventionally managed and natural forests. Data on woody vegetation and environmental conditions was collected within logging gaps and natural treefall gaps. The regeneration success of shade-tolerant timber tree species was lower in certified than in conventionally managed forests in Río Cangrejal. Furthermore, the floristic composition was more natural-like in the conventionally managed than the certified forests. However, the environmental conditions indicated reduced logging disturbance in the certified forests. Data from Copén demonstrated that the regeneration success of light-demanding timber species was higher in the certified than the unlogged forests. In spite of this, the most valuable timber species Swietenia macrophylla was not regenerating successfully in the certified forests, due to rapid gap closure. The results indicate that pre-certification loggings and forest fragmentation may have a stronger impact on forest regeneration than current, certified management practices. The focus in community forests under low-intensive logging should be directed toward landscape connectivity and the restoration of degraded timber species, instead of reducing mechanical logging damage. Such actions are dependent on better recognition of resource rights, and improving the status of small Southern producers in the markets of certified wood products.Metsäsertifiointia on pidetty lupaavana keinona hillitä metsien tuhoutumista tropiikissa. Paikallisilla yhteisöillä on omistus- tai käyttöoikeus yhä suurempaan osaan tropiikin metsiä, mutta näistä yhteisömetsistä on toistaiseksi sertifioitu vain murto-osa. Tässä tutkimuksessa tarkasteltiin FSC-metsäsertifioinnin vaikutuksia hakkuiden ekologiseen kestävyyteen Hondurasin yhteisömetsissä. Ekologista kestävyyttä arvioitiin arvopuiden uusiutumismenestyksen ja lajiston luonnontilaisuuden kautta. Kasvillisuus- ja ympäristöoloja mitattiin sertifioitujen, perinteisellä tavalla hoidettujen ja luonnonmetsien puunkaatuma-aukoissa. Oletusten vastaisesti varjoa sietävien arvopuulajien uusiutumismenestys oli heikompaa sertifioiduissa kuin perinteisellä tavalla hoidetuissa metsissä. Perinteisesti hoidettujen metsien hakkuuaukkojen lajisto oli myös enemmän luonnontilaisen lajiston kaltaista, mikä viittaa siihen, että sertifioinnilla ei ole onnistuttu parantamaan hakkuiden kestävyyttä. Ympäristömuuttujien tarkastelu kuitenkin osoitti, että hakkuuhäiriötä oli vähemmän sertifioiduissa metsissä. Valoa vaativat arvopuulajit uusiutuivat oletusten mukaisesti paremmin sertifioiduissa kuin hakkaamattomissa metsissä. Pienissä hakkuuaukoissa ei kuitenkaan välttämättä ole tarpeeksi valoa arvokkaimman puulajin, mahongin (Swietenia macrophylla) uusiutumiselle. Tulosten perusteella metsien aiempi kestämätön käyttö ja pirstaloituneisuus saattavat vaikuttaa metsän uusiutumiseen enemmän kuin vähäintensiiviset sertifioidut hakkuut. Metsikkötason mekaanisen hakkuuhäiriön vähentämisen sijaan yhteisömetsien sertifioinneissa tulisi kiinnittää enemmän huomiota maisematason yhteyksiin metsien välillä ja loppuun hakattujen puulajien palauttamiseen. Tällaisten toimenpiteiden toteuttaminen on sidoksissa metsistä saatavaan toimeentuloon ja metsien omistusoikeuksiin. Kestävyyden parantaminen onnistuu vain, jos yhteisömetsätuottajien asemaa ja kilpailukykyä sertifioitujen tuotteiden markkinoilla pystytään parantamaan

The challenges of certifying tropical community forests: A case study from Honduras

Peer reviewe

Phenotypic signatures of urbanization are scale-dependent : a multi-trait study on a classic urban exploiter

Understanding at which spatial scales anthropogenic selection pressures operate most strongly is a prerequisite for efficient conservation and management of urban biodiversity. Heterogeneity in findings on the strength and direction of urbanization effects may result from a lack of consensus on which spatial scales are most adequate when studying biotic effects of urbanization. Therefore, here, using the house sparrow (Passer domesticus) as model, we test the hypothesis that more than one spatial scale will explain variation among phenotypic stress markers. By applying a unique hierarchical sampling design enabling us to differentiate between local and regional effects of urbanization, we here show that the strength and direction of relationships with the percentage of built-up area - a simple structural measure of urbanization - vary among phenotypic stress markers and across the spatial range over which urbanization is measured. While inverse relationships with scaled body mass and bill height of adult house sparrows (Passer domesticus) were strongest when the degree of urbanization was quantified at city-level, similar relationships with corticosterone concentrations in feathers were only detected at the scale of individual home ranges. In contrast, tarsus length, wing length, and two measures of feather development were not significantly related to urbanization at any spatial scale. As the suite of phenotypic stress markers applied in this study revealed signatures of urbanization over a broad spatial range, we conclude that measures aimed at mitigating impacts of urbanization on free-ranging populations should best be implemented at multiple spatial scales too

Relationships between Riparian Vegetation, Hydrology, Climate and Disturbance across the Western United States

Flow regime, the magnitude, duration and timing of streamflow, controls the development of floodplain landforms on which riparian vegetation communities assemble. Streamflow scours and deposits sediment, structures floodplain soil moisture dynamics, and transports propagules. Flow regime interacts with environmental gradients like climate, land-use, and biomass-removing disturbance to shape riparian plant distributions across landscapes. These gradients select for groups of riparian plant species with traits that allow them to establish, grow, and reproduce on floodplains – riparian vegetation guilds. Here I ask, what governs the distributions of groups of similar riparian plant species across landscapes? To answer this question, I identify relationships between riparian vegetation guilds and communities and environmental gradients across the American West. In Chapter One, I discuss guild-based classification in the context of community ecology and streams. In Chapter Two, I identified five woody riparian vegetation guilds across the interior Columbia and upper Missouri River Basins, USA, based on species’ traits and morphological attributes. I modeled guild occurrence across environmental gradients, including climate, disturbance, channel form attributes that reflect hydrology, and relationships between guilds. I found guilds’ distributions were related to hydrology, disturbance, and competitive or complementary interactions (niche partitioning) between co-occurring guilds. In Chapter Three, I examine floodplain riparian vegetation across the American West, identifying how hydrology, climate, and floodplain alteration shape riparian vegetation communities and their guilds. I identified eight distinct plant communities ranging from high elevation mixed conifer forests to gallery cottonwood forests to Tamarisk-dominated novel shrublands. I aggregated woody species into four guilds based on their traits and morphological attributes: an evergreen tree guild, a mesoriparian shrub guild, a mesoriparian tree guild, and a drought and hydrologic disturbance tolerant shrub guild. Communities and guilds’ distributions were governed by climate directly, and indirectly as mediated through streamflow. In Chapter Four, I discuss the utility of guild-based assessments of riparian vegetation, current limitations to these approaches, and potential future applications of the riparian vegetation guild concept to floodplain conservation and management. The classification of vegetation into functional trait-based guilds provides a flexible, framework from which to understand riparian biogeography, complementing other models frameworks for riparian vegetation