Changes In Habitat Characteristics Research Articles

Location and reef size drive oyster reef restoration success

Optimizing habitat restoration success requires understanding how restoration location and design enhance the persistence and function of a restored habitat. Particular attention to the configuration of structure and its interaction with landscape‐scale processes is critical for enhancing the habitat value of restored areas. We monitored six subtidal restored oyster reefs in Pamlico Sound, North Carolina, United States, to identify how oyster demographics responded to initial habitat characteristics (e.g. reef area, volume, vertical relief, and perimeter‐to‐area ratio) and how changes in habitat characteristics over time altered suitability for oysters. Changes in reef habitat were measured by repeated mapping using bathymetric and side‐scanning sonar systems. A 2‐year time series of oyster demographic data quantified oyster response to habitat changes over time. All reefs provided habitat for the settlement and growth of oysters. Within 2 years of restoration, relative differences in oyster recruitment and survival emerged and were related to variations in reef location and two‐dimensional habitat characteristics among reefs, namely reef area and perimeter‐to‐area ratio. Larger reefs that were less fragmented resisted burial from sedimentation and enhanced oyster densities and biomass relative to smaller, more fragmented reefs that became heavily sedimented and failed to support oyster recruitment and survival. Positive feedback mechanisms between habitat characteristics and oyster recruitment success were established within 1 year of restoration and were likely driven by landscape‐scale processes such as sediment dynamics and larval supply. To improve restoration success, we recommend creating larger reef surfaces with low perimeter‐to‐area ratios in areas that promote habitat persistence.

Local and landscape drivers of natural enemy communities in Indonesian oil palm plantation

Abstract Oil palm plantations are typically managed in a monoculture system over large areas. This system contributes to biodiversity loss and promotes pest outbreaks by reducing natural enemies. However, ecosystem functions in oil palm plantations vary spatially and temporally and can still support biodiversity under certain conditions. We conducted a study on the species richness, abundance and species composition of natural enemies in oil palm plantations and investigated the factors influencing natural enemy communities in oil palm plantations at both local and landscape scales. We selected 12 sites in an oil palm plantation in Central Borneo, Indonesia, which were grouped into 4 sub‐areas based on the presence of natural habitats, which varied in local and landscape characteristics. Arthropods were sampled using canopy knockdown fogging with a pyrethroid insecticide. Different taxa of natural enemies responded differently to changes in habitat characteristics within oil palm plantations. Species richness of spiders was not affected by either local or landscape scale, but their species composition was affected by oil palm tree age (local scale) and the total edge of dominant oil palm tree age (landscape scale). Ant species richness was influenced by the class area of natural habitat (landscape scale), whereas their species composition was not influenced by either local or landscape scale. On the other hand, species richness of parasitoid wasps was influenced by light intensity (local scale) and the variation of oil palm tree age within a landscape (landscape scale). However, their species composition was only affected by light intensity. The results suggest that oil palm management practices need to consider both local and landscape scales to maintain biodiversity and biological control and to achieve sustainable management of oil palm plantations.

Urban abiotic stressors drive changes in the foraging activity and colony growth of the black garden ant Lasius niger

Changes in habitat characteristics are known to have profound effects on biotic communities and their functional traits. In the context of an urban-rural gradient, urbanisation drastically alters abiotic characteristics, e.g., by increasing environmental temperatures and through light pollution. These abiotic changes significantly impact the functional traits of organisms, particularly insects. Furthermore, changes in habitat characteristics also drive changes in the behavioural traits of animals, allowing them to adapt and thrive in new environments. In our study, we focused on the synanthropic ant species Lasius niger as a model organism. We conducted nocturnal field observations and complemented them with laboratory experiments to investigate the influence of night warming (NW) associated with Urban Heat Islands (UHI), light pollution (ALAN), and habitat type on ant foraging behaviour. In addition, we investigated the influence of elevated temperatures on brood development and worker mortality. Our findings revealed that urban populations of L. niger were generally more active during the night compared to their rural counterparts, although the magnitude of this difference varied with specific city characteristics. In laboratory settings, higher temperatures and continuous illumination were associated with increased activity level in ants, again differing between urban and rural populations. Rural ants exhibited more locomotion compared to their urban counterparts when maintained under identical conditions, which might enable them to forage more effectively in a potentially more challenging environment. High temperatures decreased the developmental time of brood from both habitat types and increased worker mortality, although rural colonies were more strongly affected. Overall, our study provides novel insights into the influence of urban environmental stressors on the foraging activity pattern and colony development of ants. Such stressors can be important for the establishment and spread of synanthropic ant species, including invasive ones, and the biotic homogenization of anthropogenic ecosystems.

Deterministic versus stochastic control in β-diversity, abundance and co-occurrence patterns of a soil nematode assemblage living in a Mediterranean soil

In this paper we studied the determinism-stochasticity trade-off affecting the structure of a soil nematode assemblage. Specifically, in a field experiment that lasted six months, the soil temperature and moisture conditions were manipulated in 14 plots. The generic composition of the soil nematode assemblage was explored by estimations of β-diversity, its turnover and nestedness components and by fitting rank abundance models. Further the associative aspects between the assemblage members and between them and habitat attributes were accounted for by analyzing the niche overlap based on Pearson correlation coefficients. Using variation partitioning and null models, we found that the generic diversity of the assemblage was more strongly determined by non-registered lateral experimental factors (stochastic control). By contrast, the deterministic control—less strong than the stochastic counterpart—was exerted both in synchronization with the changes in habitat characteristics and/or with a time delay. The network analysis showed that, under favorable habitat conditions in July, September and October, reduced network modularity and enhanced connectivity were favored, which probably led to a niche-based deterministic selection that outperformed stochasticity. Conversely, under changing experimental conditions in August and lower temperature in November and December, stochasticity would be superior to niche identity, leading to enhanced modularity and relatively loose networks.

Size segregation and seasonal patterns in rusty crayfish Faxonius rusticus distribution and abundance on northern Lake Michigan spawning reefs

Non-native rusty crayfish are abundant egg predators on spawning reef habitats for lake trout and coregonines in northern Lake Michigan. To better understand rusty crayfish life-history on these unique habitats, we conducted monitoring in 2012 and 2013 at four locations previously identified as spawning areas for native fish. With the aid of a graphical causal model, we conducted an exploratory statistical analysis using a Bayesian multilevel modeling approach with model selection based on information criteria to identify important environmental variables for predicting rusty crayfish distribution and abundance on spawning reefs. We also compared seasonal trends in relative abundance, inferred from catch-per-unit-effort calculations from trapping, to previously reported accounts from a smaller inland lake. The results from our modeling provide evidence of size-class segregation across subtle changes in habitat characteristics of spawning reefs. Specifically, we found evidence that the distribution of >30 mm rusty crayfish was only weakly related to rock density (#/m2) relative to juveniles and smaller size classes. We also observed highest relative abundances from minnow trap monitoring in mid-October when water temperatures averaged 13.9 °C, which is later in the year and at cooler temperatures than similar monitoring from smaller inland lakes has reported. We hypothesize that unique environmental conditions elicit novel life-history responses from rusty crayfish on Lake Michigan spawning reefs and discuss our findings in the context of native fish restoration in the Laurentian Great Lakes.

Changes in soil arthropod communities and soil biological quality along an elevation gradient in Taurus Fir forest

Orman ekosistemlerindeki toprak eklembacaklıları (Arthropoda), ölüörtünün parçalanması ve ayrışması sürecinde, birincil ve ikincil tüketiciler olarak önemli rol almaktadır. Toprak ekosistemindeki eklembacaklıların miktarı, çeşitliliği ve komünite yapısı; yetişme ortamı özelliklerinin değişimine çok hızlı tepki vermektedir. Bu çalışmada, Toros Göknarı (Abies cilicica (Antoine & Kotschy) Carrière) ekosisteminde yaşayan toprak eklembacaklılarının farklı yükseltilerde mevsimsel değişimleri, çeşitlilikleri ve biyolojik toprak kalitesine olan etkilerinin ortaya konması amaçlanmıştır. Çalışma, Berçin Yaylası (Tomarza-Kayseri) saf göknar meşcerelerinde, 1600-1730 metre yükseltiler arasındaki (3 farklı yükseltide) yürütülmüştür. Ölü örtüden 10 cm çapında ve yüksekliğinde çelik silindir kullanılarak yapılan örnekleme kış, ilkbahar, yaz ve sonbahar mevsimlerinde yapılmıştır. Eklembacaklıların, mevsimsel ve farklı yükseltilerdeki miktarları, çeşitlilikleri, trofik yapıları ve toprak biyolojik kalitesi (QBS) değerleri belirlenmiştir. Toprak biyolojik kalitesi eklembacaklılar kullanılarak belirlenirse QBS-ar, Collembola taksonu kullanılarak belirlenirse QBS-C olarak adlandırılır. Çalışma sonucunda, eklembacaklıların mevsimlere göre dağılımında en fazla birey yaz mevsiminde, yükseltiye bağlı dağılımında ise en fazla birey 1613 m yükseltide bulunmuştur. Yükseltiler arasında çeşitlilik indeksi bakımından fark bulunamamıştır. Toprak biyolojik kalitesi hem QBS-ar hem de QBS-C değeri yükselti ile azalmaktadır. Teşhis edilen Collembola türleri Kayseri/ Berçin Yaylası için yeni kayıt iken Protaphorura microsellata türü Türkiye için yeni kayıttır.

The impact of Acacia saligna and the loss of mobile dunes on rodent populations: a case study in the Ashdod-Nizzanim sands in Israel

The Mediterranean coastal dune habitat of Israel is diminishing rapidly, mostly due to massive urbanization, changes in habitat characteristics caused by dune stabilization and the presence of Acacia saligna, an invasive species brought to Israel for the purpose of dune stabilization. In this study we document the effect of sand stabilization on the composition of small mammal communities in the Ashdod-Nizzanim sands, Israel. We analyzed differences in species diversity and abundance for species of rodents in four types of habitat: unstable (mobile) sand dune, semi-stabilized dune, inter-dune depression and a plot of the invasive Acacia saligna. Rodent communities were found to undergo gradual changes concurrently with the stabilization of the sands. The mobile dune was the only habitat in which the strict psammophiles Jaculus jaculus and Gerbillus pyramidum were captured in abundance. No species commensal with human were captured neither in the mobile nor in the semi-stabilized dunes. However, in the inter-dune depression there was quite a large representation of Mus musculus, a rodent commensal with humans. The Acacia saligna plot had the lowest number of captures and the lowest rodent biomass calculated, with Mus musculus composing nearly half of the captures. The results of this study demonstrate that stabilization of the sands in Ashdod-Nizzanim area is associated with the disappearance of psammophile rodents and the appearance of species commensal with humans. In order to preserve the habitat for psammophile rodents, measures should be taken to halt the spread of acacia and the continuing stabilization of the sands.

Biogeography of arbuscular mycorrhizal fungal communities in saline ecosystems of northern China

Arbuscular mycorrhizal (AM) fungi, influencing many important ecosystem processes, widely occur in saline soils, and thus understanding their biogeographic patterns is of primary interest in saline ecosystem restoration. Fine roots and rhizosphere soils were sampled in black locust (Robinia pseudoacacia) plantations in four saline sites in northern China to detect soil properties and AM fungal attributes including their colonization level, spore density, hyphal density and community composition. Arbuscular mycorrhizal fungal attributes varied with sampling sites, and this variation was mostly attributed to changes in habitat characteristics and geographic distance. Habitat characteristics shape the root- and soil-inhabiting AM fungal communities to the same extent, whereas geographic distance seems to contribute more to root-inhabiting AM fungal assemblages. The level of root colonization by vesicles, arbuscules and hyphae and the density of AM fungal spores and hyphae in soils were found to be related to the relative abundance of AM fungal species such as root-inhabiting Rhizophagus intraradices and soil-inhabiting Sclerocystis sinuosa. All the results suggest that changes in habitat characteristics and geographic distance may induce biogeographic patterns of AM fungi, and these patterns are closely related to AM symbiosis in roots and the development of AM fungi in soils.

Response of macroinvertebrate communities to hydrological and hydrochemical alterations in Mediterranean streams

Mediterranean rivers are affected by natural disturbances and human pressures, which may alter their hydrology, water quality and habitat structure. In this study an analysis of macroinvertebrates community structure has been used to determine how distinct human pressures, such as point and non-point sources of pollution, together with groundwater withdrawal, may affect these ecosystems. A total of 4 sampling campaigns were conducted in the middle reach of the Onyar River (NE Spain), which was affected by agricultural and urban uses. Stream discharge and physicochemical parameters were measured in situ, and water samples and macroinvertebrates assemblages were taken and properly preserved for subsequent analysis and identification. Variation partitioning showed that macroinvertebrate community structure was particularly dependent on hydrochemical characteristics, but also on hydrological variations. In addition, results indicated that groundwater withdrawal altered stream hydrology, and the main reach of the Onyar River became intermittent and even completely dry in downstream positions. This reduction on stream discharge caused changes in habitat characteristics, as well as in the proportion of wastewater. Some wastewater dilution occurred, linked to groundwater with high nitrate concentrations inputs to the stream, and even though the macroinvertebrate community recovered its quality in some sampling campaigns, it presented a different structure than in sampling points not affected by any of these pressures. Therefore, the approach here used to analyze the hydrological effects on macroinvertebrate communities allowed us to determine their influence on hydrochemical and habitat characteristics.

Body Length Determines the Diet and Niche Specialization of Non-Biting Midge Predator (Tanypodinae) Larvae in Shallow Reservoirs.

The functional traits of species respond to environmental gradient changes, which, in turn, are responsible for the niche specialization of species. We analyzed the niche specialization of several Tanypodinae taxa (predatory non-biting midge, 4th instar, n = 693) along the depth zones of the water in six shallow tropical reservoirs. We measured the body length and diet composition of seven Tanypodinae larvae genus. Community-weighted mean (CWM) traits index was utilized to calculate the niche distribution of body length and diet composition. We analyzed the niche distribution of predator larvae, through a simple linear analysis of CWM index and the depth of the water, and by establishing correlations between body length and diet composition. In our study, it was found that the consumption of oligochaete (b = 0.30, SE ± 0.04, t = 7.02, p = 0.0001, R2 = 0.45) and the body length (b = 0.64, SE ± 0.11, t = 5.44, p = 0.0001, R2 = 0.33) increased in deeper zones. We observed a strong and positive relationship between oligochaete consumption and a longer body (r = 0.91, p = 0.0001). We inferred that changes in habitat characteristics, from littoral to deeper zones of the reservoirs, are expected to have influenced the selection of larvae traits predators. We concluded that body length determines the diet consumption and accurately reflects the niche distribution of Tanypodinae assemblages. The functional trait approach proved to be an efficient tool for the analysis of the ecological processes that determine the structure of a non-biting midge predator assemblage.

Detection of seagrass scars using sparse coding and morphological filter

The proximity of seagrass meadows to centers of human activity makes them vulnerable to a variety of habitat degrading insults. Physical scarring has long been recognized as an important but difficult-to-quantify source of habitat fragmentation and seagrass loss. We present a pixel-based algorithm to detect seafloor propeller seagrass scars in shallow water that promises to automate the detection and measurement of scars across the submarine landscape.11A preliminary version of the paper was presented at the SPIE Remote Sensing Conference, Amsterdam, Netherlands, 2014 (Oguslu et al., 2014). We applied the algorithm to multispectral and panchromatic images captured at the Deckle Beach, Florida using the WorldView-2 commercial satellite. The algorithm involves four steps using spectral and spatial information from radiometrically calibrated multispectral and panchromatic images. First, we fused multispectral and panchromatic images using a principal component analysis (PCA)-based pan-sharpening method to obtain multispectral pan-sharpened bands. In the second step, we enhanced the image contrast of the pan-sharpened bands for better scar detection. In the third step, we classified the contrast enhanced image pixels into scar and non-scar categories based on a sparse coding algorithm that produced an initial scar map in which false positive scar pixels were also present. In the fourth step, we applied post-processing techniques including a morphological filter and local orientation to reduce false positives. Our results show that the proposed method may be implemented on a regular basis to monitor changes in habitat characteristics of coastal waters.

Decadal changes in habitat characteristics influence population trajectories of southern elephant seals.

Understanding divergent biological responses to climate change is important for predicting ecosystem level consequences. We use species habitat models to predict the winter foraging habitats of female southern elephant seals and investigate how changes in environmental variables within these habitats may be related to observed decreases in the Macquarie Island population. There were three main groups of seals that specialized in different ocean realms (the sub-Antarctic, the Ross Sea and the Victoria Land Coast). The physical and climate attributes (e.g. wind strength, sea surface height, ocean current strength) varied amongst the realms and also displayed different temporal trends over the last two to four decades. Most notably, sea ice extent increased on average in the Victoria Land realm while it decreased overall in the Ross Sea realm. Using a species distribution model relating mean residence times (time spent in each 50×50km grid cell) to 9 climate and physical co-variates, we developed spatial predictions of residence time to identify the core regions used by the seals across the Southern Ocean from 120°E to 120°W. Population size at Macquarie Island was negatively correlated with ice concentration within the core habitat of seals using the Victoria Land Coast and the Ross Sea. Sea ice extent and concentration is predicted to continue to change in the Southern Ocean, having unknown consequences for the biota of the region. The proportion of Macquarie Island females (40%) utilizing the relatively stable sub-Antarctic region, may buffer this population against longer-term regional changes in habitat quality, but the Macquarie Island population has persistently decreased (-1.45% per annum) over seven decades indicating that environmental changes in the Antarctic are acting on the remaining 60% of the population to impose a long-term population decline in a top Southern Ocean predator.

Testing for longitudinal zonation of macroinvertebrate fauna along a small upland headwater stream in two seasons

AbstractThe effect of longitudinal zonation patterns and macroinvertebrate responses to changes in habitat characteristics have been given a lot of attention. But studies of changes in macroinvertebrate assemblages along small upland undisturbed watercourses are still lacking. The aim of the study is to analyse variability in macroinvertebrate communities between two different habitats/morphological sequences – shallow (riffle/run/step/) and deeper (pool) channel-bed morphological units on the background of the environmental parameters (local relief, slope, channel confinement ratio, channel-valley walls connectivity, floodplain continuity and channel abut, channel sinuosity and predominant land cover of riparian zone) of seven valley segments (functional process zones) in two seasons of the year (spring and autumn). The longitudinal-downstream gradient research was conducted on the semi-natural upland headwater brook in the Little Carpathians (9,330 m long, average gradient 2.8%) at 15 morphological sequences (30 sampling points). Each sampling point in spring as well as in autumn was characterised by mean flow velocity, discharge, water depth, channel width, channel bottom particle size, and flow types. Selected physico-chemical variables: pH, dissolved oxygen content (DO), oxygen saturation (DO %), temperature (t) conductivity and total dissolved solids (TDS) were measured directly in the field using the multisonde measuring device. Organisms were identified into the family level. The results showed that differences in zonation of benthic invertebrates between seasons are more apparent than seasonal variability between pools and riffles. Spring samples followed the increasing gradient of total dissolved solids downstream with characteristic families for upper and lower stretch. The disruption of macroinvertebrates zonation was more evident in autumn samples with greatest effects in pools. Based on RDA, the distribution of families was driven by three significant variables in riffles and four in pools. Alike environmental factors of pool sequences in the middle and upper reaches were responsible for similarity in macroinvertebrate structure. In conclusion, the distribution pattern of benthic invertebrates of the natural part of the small headwater stream in terms of abundance of macroinvertebrate families followed the longitudinal zonation in spring, but in autumn were the local habitat conditions more important.

Combined effects of climatic gradient and domestic livestock grazing on reptile community structure in a heterogeneous agroecosystem.

Grazing plays an important role in shaping ecological communities in human-related ecosystems. Although myriad studies have explored the joint effect of grazing and climate on plant communities, this interactive effect has rarely been studied in animals. We hypothesized that the effect of grazing on the reptile community varies along a climatic gradient in relation to the effect of grazing on habitat characteristics, and that grazing differentially affects reptiles of different biogeographic regions. We tested our hypotheses by collecting data on environmental characteristics and by trapping reptiles in four heterogeneous landscapes experiencing differing grazing intensities and distributed along a sharp climatic gradient. We found that while reptile diversity increased with grazing intensity at the mesic end of the gradient, it decreased with grazing intensity at the arid end. Moreover, the proportion of reptile species of differing biogeographic origins varied with the interactive effect of climate and grazing. The representation of species originating in arid biogeographic zones was highest at the arid end of the climatic gradient, and representation increased with grazing intensity within this area. Regardless of the climatic context, increased grazing pressure results in a reduction in vegetation cover and thus in changes in habitat characteristics. By reducing vegetation cover, grazing increased habitat heterogeneity in the dense mesic sites and decreased habitat heterogeneity in the arid sites. Thus, our results suggest that the same direction of habitat alteration caused by grazing may have opposite effects on biodiversity and community composition in different climatic contexts.

Structure and importance of soil-protecting forests in the areas administered by the RDSF Toruń

Abstract The paper presents the state and importance of soil-protecting forests in the areas managed by the RDSF in Toruń, as well as changes in their structure over 29 years. The management of the RDSF in Toruń is characterized by a systematic increase in the area, thickness and rich abundance of soil-protecting forests, particularly intense since the mid-nineteen-nineties. They cover mainly rusty soils and podzols on outwash areas, sandy terraces in sloped areas of postglacial valleys and gullies as well. Soil-protecting forests, which are managed by the RDSF in Toruń, vary a great deal considering their habitat, both in terms of dampness and trophic richness as well as spatially. The dominance of coniferous forests is due to the fact that they grow in the poorest habitats, which have not been previously used for agricultural purposes, and to the common practice in recent years of pine reforestation in open stromal areas. The assessment of the state of habitats indicates that 66.2% of the soil-protecting forest area is characterized as natural and close-to-natural. Distorted or transformed habitats occupy 26.2% of the soil-protecting forest area, while the degraded habitats 7.6%. Taking the study area into consideration we can observe the relationship between the incompatibility of habitat in its natural form and the post-arable feature. Changes in habitat characteristics are shown by 75.5% of the area of the soil-protecting forest located on former farmland, mainly in the areas with rusty podzolic soils (Albic Brunic Arenosols). Incompatibility of the habitats is, among others, the result of the creation in recent years, during the afforestation of agricultural lands, of solid pine stands, also in fertile habitats. Secondary planted pine monocultures in the forest areas resulted in podzolization of rusty soils and transformed them into rusty podzolic soils.

Structure and importance of soil-protecting forests in the areas administered by the RDSF Toruń

The paper presents the state and importance of soil-protecting forests in the areas managed by the RDSF in Torun, as well as changes in their structure over 29 years. The management of the RDSF in Torun is characterized by a systematic increase in the area, thickness and rich abundance of soil-protecting forests, particularly intense since the mid-nineteen-nineties. They cover mainly rusty soils and podzols on outwash areas, sandy terraces in sloped areas of postglacial valleys and gullies as well. Soil-protecting forests, which are managed by the RDSF in Torun, vary a great deal considering their habitat, both in terms of dampness and trophic richness as well as spatially. The dominance of coniferous forests is due to the fact that they grow in the poorest habitats, which have not been previously used for agricultural purposes, and to the common practice in recent years of pine reforestation in open stromal areas. The assessment of the state of habitats indicates that 66.2% of the soil-protecting forest area is characterized as natural and close-to-natural. Distorted or transformed habitats occupy 26.2% of the soil-protecting forest area, while the degraded habitats 7.6%. Taking the study area into consideration we can observe the relationship between the incompatibility of habitat in its natural form and the post-arable feature. Changes in habitat characteristics are shown by 75.5% of the area of the soil-protecting forest located on former farmland, mainly in the areas with rusty podzolic soils (Albic Brunic Arenosols). Incompatibility of the habitats is, among others, the result of the creation in recent years, during the afforestation of agricultural lands, of solid pine stands, also in fertile habitats. Secondary planted pine monocultures in the forest areas resulted in podzolization of rusty soils and transformed them into rusty podzolic soils.

The emergence densities of annual cicadas (Hemiptera: Cicadidae) increase with sapling density and are greater near edges in a bottomland hardwood forest.

The emergence densities of cicadas tend to be patchy at multiple spatial scales. While studies have identified habitat conditions related to these patchy distributions, their interpretation has been based primarily on periodical cicada species; habitat factors associated with densities of nonperiodical (i.e., annual) cicadas have remained under studied. This is despite their widespread distribution, diversity, and role as an important trophic resource for many other organisms, particularly within riparian areas. We studied habitat factors associated with the emergence densities of Tibicen spp. in a bottomland hardwood forest in east-central Arkansas. We found emergence densities were greatest in areas of high sapling densities and increased toward forest edges, although sapling density was a much stronger predictor of emergence density. Emergence densities also differed among sample areas within our study system. The habitat features predicting nymph densities were likely driven by a combination of factors affecting female selection of oviposition sites and the effects of habitat conditions on nymph survival. The differences in nymph densities between areas of our system were likely a result of the differential effects of flooding in these areas. Interestingly, our findings were similar to observations of periodical species, suggesting that both types of cicadas select similar habitat characteristics for ovipositing or are under comparable selective pressures during development. Our findings also imply that changes in habitat characteristics because of anthropogenically altered disturbance regimes (e.g., flooding) have the potential to negatively impact both periodical and annual species, which could have dramatic consequences for organisms at numerous trophic levels.

Using landscape and bioclimatic features to predict the distribution of lions, leopards and spotted hyaenas in Tanzania's Ruaha landscape.

Tanzania's Ruaha landscape is an international priority area for large carnivores, supporting over 10% of the world's lions and important populations of leopards and spotted hyaenas. However, lack of ecological data on large carnivore distribution and habitat use hinders the development of effective carnivore conservation strategies in this critical landscape. Therefore, the study aimed to (i) identify the most significant ecogeographical variables influencing the potential distribution of lions, leopards and spotted hyaenas across the Ruaha landscape; (ii) identify zones with highest suitability for harbouring those species; and (iii) use species distribution modelling algorithms (SDMs) to define important areas for conservation of large carnivores. Habitat suitability was calculated based on environmental features from georeferenced presence-only carnivore location data. Potential distribution of large carnivores appeared to be strongly influenced by water availability; highly suitable areas were situated close to rivers and experienced above average annual precipitation. Net primary productivity and tree cover also exerted some influence on habitat suitability. All three species showed relatively narrow niche breadth and low tolerance to changes in habitat characteristics. From 21,050 km2 assessed, 8.1% (1,702 km2) emerged as highly suitable for all three large carnivores collectively. Of that area, 95.4% (1,624 km2) was located within 30 km of the Park-village border, raising concerns about human-carnivore conflict. This was of particular concern for spotted hyaenas, as they were located significantly closer to the Park boundary than lions and leopards. This study provides the first map of potential carnivore distribution across the globally important Ruaha landscape, and demonstrates that SDMs can be effective for understanding large carnivore habitat requirements in poorly sampled areas. This approach could have relevance for many other important wildlife areas that only have limited, haphazard presence-only data, but which urgently require strategic conservation planning.

A Multi-Scale Evaluation of the Effects of Forest Harvesting for Woody Biofuels on Mammalian Communities in a Northern Hardwood Forest

Research addressing the implications of forest harvesting for mammals has focused on different categories of silvicultural prescriptions. However, the effects of these prescriptions on forest structure can vary considerably, and categories of prescriptions rarely incorporate the market for which timber is being harvested. The latter information is important given the recent shift from conventional round-wood harvesting to wholetree removal for biofuels production, and corresponding reductions in post-harvest woody biomass left on-site. Our goal was to assess the effects of forest harvesting for biofuels on mammal species. Objectives included 1) evaluating how structural components influenced mammals, and 2) assessing the role of scale on species-habitat relationships. We sampled mammals in a 97-ha area of hardwood forest in the Adirondack Mountains in New York that had been partially harvested for biofuels in 2010. We used Sherman traps and track plates to assess the distribution of mammals. We captured 6 species of mammals in Sherman traps and identified 8 species using track plates. Mammalian species varied in their sensitivity to changes in habitat characteristics associated with biofuels harvest (coarse woody debris and slash). Our study reveals a complex suite of factors driving the response of mammals to variation in forest structure as a result of biofuels production. The harvesting practices used in the focal region are unlikely to lead to dramatic changes in the abundance and distribution of individual species of small mammals, but may influence the occurrence of common species including deer-mice and voles.

Effects of Fungal Inocula and Habitat Conditions on Alder and Eucalyptus Leaf Litter Decomposition in Streams of Northern Spain

We investigated how fungal decomposer (aquatic hyphomycetes) communities colonizing alder and eucalyptus leaf litter respond to changes in habitat characteristics (transplantation experiment). We examined the breakdown of leaf materials and the associated fungal communities at two contrasting sites, a headwater stream (H) and a midreach (M). Agroforestry increased from headwater to midreach. One month after the start of experiments at both sites, some leaf samples from the midreach site were transplanted to the headwater site (M-H treatment). Although both sites showed similar dissolved inorganic nutrient concentrations, eucalyptus leaves initially incubated at the midreach site (M, M-H) increased their breakdown rate compared to those incubated along the experiment at the headwater site (H). Alder breakdown rate was not enhanced, suggesting that their consumption was not limited by nutrient availability. Sporulation rates clearly differed between leaf types (alder > eucalyptus) and streams (H > M), but no transplantation effect was detected. When comparing conidial assemblages after transplantation, an inoculum effect (persistence of early colonizing species) was clear in both leaf species. Substrate preference and shifts in the relative importance of some fungal species along the process were also observed. Overall, our results support the determining role of the initial conditioning phase on the whole litter breakdown process, highlighting the importance of intrinsic leaf characteristics and those of the incubation habitat.