Can perennial dominant grass <Emphasis Type="Italic">Miscanthus sinensis</Emphasis> be nurse plant in recovery of degraded hilly land landscape in South China?

Perennial C₄ grasses, especially Miscanthus sinensis, are widely distributed in the degraded lands in South China. We transplanted native and exotic tree seedlings under the canopy of M. sinensis to assess the interaction (competition or facilitation) between dominant grass M. sinensis and tree seedlings. The results of growth, chlorophyll fluorescence, and ultrastructure showed that negative effects may be stronger in perennial dominant grass M. sinensis. Although M. sinensis buffered the air temperature, improved soil structure, and increased soil phosphorus content, these beneficial effects were outweighed by the detrimental effect, especially overshading. To ensure the establishment of target native species in M. sinensis communities in degraded lands of South China, restoration strategies should include removing aboveground vegetation, planting target species seedlings in openings to reduce the effects of canopy shading, and/or selecting competition-tolerant target species. Also, seedlings of exotic species used in restoration engineering cannot be directly planted under the canopy of M. sinensis.     

Herbivory on planted oak seedlings across a habitat edge created by timber harvest

Edge habitats create environmental gradients that affect plant community composition and herbivore behavior. Silvicultural disturbance creates edge habitat with direct (via changes in light) and indirect (via changes in herbivore behavior) consequences for the growth and survival of tree seedlings, and thus, the composition of the future forest stands. Herbivores, particularly ungulates, can be a major limiting factor in oak regeneration, and silvicultural disturbance may alter the abundance or behavior of herbivores following harvest. We measured the severity of herbivory on experimentally planted white (Quercus alba) and black oak (Quercus velutina) seedlings by white-tailed deer (Odocoileus virginianus) and eastern cottontail rabbits (Sylvilagus floridanus), as well as foliar damage from insects, across gradients created by clearcuts in a deciduous forest in Indiana, USA. Overall browse pressure on oaks was low in our study. Nonetheless, spatial variation in herbivory depended on herbivore taxa; herbivory by rabbits was highest inside harvest openings, whereas foliar damage by insects peaked in the forest. Intensity of deer herbivory was constant across the edge. In addition, we observed indirect interactions among herbivore species mediated by a seedling’s browsing history. Herbivore damage by deer was positively related to past browsing by rabbits, and foliar damage from insects was positively related to past browsing by both deer and rabbits. Increasing woody plant competition reduced herbivory on seedlings by both deer and rabbits. Given the lack of spatial variability in deer herbivory and low overall herbivory by rabbits, we suspect that interactions between timber harvesting and herbivory did not have a strong impact on oak seedlings at our study sites.     

The role of the soil seed and seedling bank in the regeneration of diverse plant communities in the subtropical Ailao Mountains,Southwest China

We compared species composition and diversity of the soil seed and seedling banks in three secondary vegetation types (shrubland, Populus bonatii forest, Lithocarpus regrowth forest) and a primary old-growth forest in the subtropical Ailao Mountains of southwestern China to clarify the importance of seed and seedling banks for forest dynamics. The average species richness was the highest in soil samples from the shrubland (26.80 ± 1.98), and the lowest from the primary forest (9.93 ± 0.50). The density of germinable tree seeds increased from the secondary vegetation to the primary forest, and the density of shrub, forb, and graminoid seeds decreased significantly. The most abundant seedlings recorded in soil samples were light-demanding species in the shrubland and Populus bonatii forest. For ground flora, the number of shrub seedlings strongly decreased with the increase in stand age, and shade-tolerant tree seedlings tended to increase. The species similarity between the seed bank and the aboveground vegetation in all sites was low (Sørensen’s index = 0.11–0.33), however, the shrubland had higher similarity compared with the other three plant communities. In the primary forest, light-demanding woody species dominated in soil seed banks, while shade-tolerant species dominated in the overstory and the forest floor. In the primary forest, seedlings of dominant tree species were rare in the understory, and no seeds of the dominant species were found in the soil. Results indicated that the early stages of vegetation recovery should take into account the possibility of recovering soil seed bank processes. However, colonization and establishment of tree seedlings will be difficult once a primary forest is destroyed.     

Ectomycorrhizal fungal exoenzyme activity differs on spruce seedlings planted in forests versus clearcuts

Key message

Ectomycorrhizal (ECM) fungal community structure and potential exoenzymatic activity change after clearcut harvesting, but functional complementarity and redundancy among those ECM fungal species remaining support growth of regenerating seedlings.

Abstract

Ectomycorrhizal (ECM) fungal community composition is altered by forest harvesting, but it is not clear if this shift in structure influences ECM fungal physiological function at the community level. In this study, we characterized activities of extracellular enzymes in the ectomycorrhizospheres of Picea engelmannii seedlings grown in forest and clearcut plots. These exoenzymes are critical for the breakdown of large organic molecules, from which nutrients are subsequently absorbed and translocated by ECM fungi to host plants. We found that ectomycorrhizae on seedlings planted in forests had different exoenzyme activity profiles than those on seedlings planted in clearcuts. Specifically, the activities of glucuronidase, laccase, and acid phosphatase were higher on forest seedlings (P ≤ 0.006). These differences may have been partly driven by soil properties. Total carbon, total nitrogen (N), extractable phosphorus, extractable ammonium-N, and mineralizable N were higher, while pH was lower in forest plots (P ≤ 0.01). However, we also found that enzyme activity only shifted where community composition also changed. Functional complementarity can be inferred within ECM fungal communities in both forests and clearcuts because ectomycorrhizae formed by different species in the same environment had distinct enzyme profiles (P < 0.0001). However, ectomycorrhizae of Thelephora terrestris exhibited high levels of N- and P-mobilizing exoenzyme activities. Seedling biomass did not differ between forest and clearcut environments, so the high abundance of T. terrestris ectomycorrhizae in the clearcuts may have sustained nutrient acquisition by clearcut seedlings even in soils with lower N and P and with reduced ECM fungal species richness.

     

Phytosociology as a tool for forest restoration: a study case in the extreme South of Atlantic Forest Biome

The biodiversity loss, due to anthropic activities, has generated the necessity of studies that enable the ecosystem conservation. Nevertheless, the majority of studies restrict themselves to the floristic composition and phytosociological structure from determined pre-established diameter, neglecting attributes of the species, such as its (their) niche (s) of occurrence in the forest, thus, making it difficult to identify potential species for restoration. In this way, the present study aimed to evaluate the structure of a forest fragment in the extreme South of Atlantic Forest Biome, through identification of species in the different layers. There were used 18 parcels of 10 m × 20 m, distributed systematically, where the vegetation was evaluated in four size classes. The characterization of the structure of the arboreal-shrub of the forest was performed by the data comparison of the floristic composition and phytosociological structure. In the fragment of forest studied, there were sampled a total of 2.176 individuals. The floristic composition of the area includes 74 species, belonging to 58 genera and 28 botanical families. We observed differences in relation of richness and diversity of species among the analyzed layers, the intermediate layer presented the lowest richness of species, being the pioneers and initial secondaries the least representatives. Trichilia claussenii, Sorocea bonplandii, Actinostemon concolor, Apuleia leiocarpa and Nectandra megapotamica were the most abundant species and well distributed in the different size classes, and they can be used in the enrichment of areas in process of restoration in the scope of the Deciduous Seasonal Forest in the extreme South of Atlantic Forest Biome. Ocotea puberula, Allophylus edulis, Cedrela fissillis and Machaerium paraguariense formed a group of species with expressive representativeness in the arboreal layer, thus they can be used in the moment of planting as species to the fast covering of the area.     

Variation in the composition and activity of ants on defense of host plant <Emphasis Type="Italic">Turnera subulata</Emphasis> (Turneraceae): strong response to simulated herbivore attacks and to herbivore’s baits

Plants with extrafloral nectaries attract a variety of ant species, in associations commonly considered mutualistic. However, the results of such interactions can be context dependent. Turnera subulata is a shrub widely distributed among disturbed areas which has extrafloral nectaries at the base of leaves. Here, we evaluated whether the ants associated with T. subulata (i) vary in space and/or time; (ii) respond to simulated herbivory, and (iii) reduce herbivory rates. For this, we quantified the abundance and species richness of ants associated with T. subulata throughout the day in six different sites and the defensive capability of these ants under simulated herbivory in the leaves and stems of T. subulata plants (N = 60). We also checked the proportion of the lost leaf area and quantified leaf damage by chewing herbivores in the host plant. We found that a total of 21 ant species associated with the host plant. Species composition showed significant variation across the sampled sites and throughout the day. Visitation rates and predation by ants were higher in plant stems than in leaves. In general, herbivory rates were not correlated with ant association or activity, with the exception of the proportion of leaf area consumed; there was a significant lower herbivory rate on plants in which ants defended the leaves. Our results suggest that the benefits of association may depend on the ecological context. This context dependence may mask the correlation between the defense of ants and herbivory rates.     

Do biological invasions by <Emphasis Type="Italic">Eupatorium adenophorum</Emphasis> increase forest fire severity?

The invasive species Eupatorium adenophorum is known to influence stand structure and wildfire the hazard in forests. In the current work, we quantitatively examined fire effects in invaded and uninvaded plots in southwestern Sichuan Province, China, with five different forest sites that had different types of dominant species: Pinus yunnanensis, P. yunnanensis–Quercus spp., Keteleeria fortunei, K. fortunei–Quercus spp., and Eucalyptus robusta. We compared the fuel chemistry (moisture, ash, heat value, and ignition point) and fire severity (flame length, fire intensity) under three burning conditions between the invaded and uninvaded plots in each forest sites, and then analyzed the results using multivariate response permutation procedures (MRPP). The burning conditions included: low (fine fuel moisture of 15 % and 5 km/h windspeed), moderate (fine fuel moisture of 10 % and 15 km/h windspeed), and extreme (fine fuel moisture of 5 % and 30 km/h windspeed). With all five sites, the fire severity and fuel loads were clearly significantly higher at the invaded sites. Fire severity was also intensified in the invaded coniferous sites compared to their mixed forest sites. These results indicate that biological invasions may increase the surface fire severity, perhaps through an increase in the heat value, and fuel loads, while reducing the moisture, ash, and ignition point of the understory herbaceous.     

Performance of two alpine plant species along environmental gradients in an alpine meadow ecosystem in central Tibet

Understanding how biotic interactions and abiotic conditions affect plant performance is important for predicting changes in ecosystem function and services in variable environments. We tested how performances of Astragalus rigidulus and Potentilla fruticosa change along gradients of biotic interactions (represented by plant species richness, abundance of the dominant plant species Kobresia pygmaea, and herbivory intensity) and abiotic conditions (represented by elevation, aspect, and slope steepness) across a semi-arid landscape in central Tibet. Redundancy analyses showed that the biotic variables explained 30 and 39 % of the variation in overall performance of A. rigidulus (P = 0.03) and P. fruticosa (P = 0.01), respectively. Abiotic variables did not contribute significantly to variation among A. rigidulus populations. Plant size decreased with species richness in both species and was larger on south- rather than north-facing slopes. Reproductive effort for both species was significantly negatively related to the abundance of K. pygmaea and both species had larger reproductive effort on south- rather than north- and west-facing slopes. The proportion of biomass allocated to sexual reproduction in P. fruticosa was negatively correlated with K. pygmaea abundance and herbivory intensity. The population density of P. fruticosa was positively related to elevation, species richness, and K. pygmaea abundance. We conclude that plant performance at a local scale was more strongly related to biotic than abiotic conditions, but different components of plant performance responded differently to predictor variables and the responses were species-specific. These findings have important implications for rangeland management under changing environmental conditions.     

Density of Primates in Four Semi-deciduous Forest Fragments of São Paulo,Brazil

Populational parameters of primates in the remaining southeastern Brazilian Atlantic Forest have been estimated, but investigations are biased to coastal evergreen sites. In this study density of three primate species was assessed through line-transect surveys in four semi-deciduous forest fragments (240 to 1450 ha) in Fazenda Barreiro Rico, eastern range of central Plateau of São Paulo state, Brazil. A total of 274 km was surveyed from January to October 2000. I estimated densities via DISTANCE software. Two of the largest fragments contained five primate species while two of the smallest ones harboured, respectively, four and two species. Densities of Cebus apella (15.34–47.92 ind./km²), Alouatta guariba (8.32–34.61), and Brachyteles arachnoides (19.92–35.11) were considerable. Differently from C. apella and A. guariba, B. arachnoides presented a density higher than previously estimated for the largest patch. The hypothetical minimum total population of B. arachnoides (601) may be the largest in semi-deciduous sites. This reinforces the value of the area in terms of its relative contribution for conservation of this endangered species. The narrow spatial scale distribution of forest fragments at Barreiro Rico and its proximity to academic institutions make the site suitable for programs of forest connectivity, studies on conservation biology, and wildlife management endeavours.     

Genetic diversity and population structure of a drought-tolerant species of <Emphasis Type="Italic">Eucalyptus</Emphasis>, using microsatellite markers

Given the impact of climate change on the availability of water resources, it becomes necessary the use of plant species well suited to planting on dryland sites. Eucalyptus cladocalyx, a native tree of South Australia, is capable of growing under relatively dry environments and saline soils. Two hundred twenty simple sequence repeat (microsatellites) markers, from a consensus linkage map of Eucalyptus, were selected to examine genetic diversity and population structure in a collection of E. cladocalyx introduced to southern Atacama Desert, Chile. A total of 130 microsatellites were successfully amplified, some of which are associated with quantitative traits of interest in Eucalyptus. Genetic analysis revealed a total of 457 alleles, ranging from 2 to 8 alleles per locus. A moderate level of genetic diversity (He = 0.492) and differentiation (FST = 0.086) was found among the populations. Mount Remarkable and Marble Range showed the highest and lowest level of genetic diversity, respectively. The Bayesian clustering analysis revealed three homogeneous genetic groups confirming that the individuals of E. cladocalyx from natural forest are highly and significantly structured. These results provide a novel information for the development of breeding strategies in E. cladocalyx by using marker-assisted selection in regions with low rainfall patterns.     

Factors determining species richness of soil seed banks in lowland ancient woodlands

The demise of coppicing in UK ancient woodlands, combined with the planting of non-native, fast-growing conifers in the twentieth century, heightens the potential recharge value of ground flora seed banks. Soil cores from adjoining semi-natural and conifer-containing stands in four lowland ancient woods in central England were removed to establish seed bank species richness. During a fourteen-month germination trial soil from two depths yielded 6554 seedlings from 81 species, ten of which showed a strong affinity for ancient woodland conditions. Juncus effusus accounted for 80% of emergent seeds whilst 23 other species, including Lysimachia nummularia and Potentilla sterilis, were represented by only one individual. Species richness is described by a model that explains 40% of observed variance (P < 0.00001). The model has three significant variables: species richness increases as soil pH rises, and decreases with both depth and increasing time since the most recent planting/disturbance event. No difference was found in the density of seeds from species common to paired semi-natural and conifer-containing stands that were separated only by a woodland ride, suggesting prior management and environmental conditions have a greater influence on seed banks than current stand type. Sørensen similarity index values revealed poor congruence between above-ground vegetation and species in the seed bank. Taking pH measurements in conifer stands identified as younger in terms of planting/disturbance may help locate areas where greater numbers of species (including woodland specialists) are located. Caution is required, however, as these seed banks may also contain non-target, competitive species that may swamp the regeneration of woodland specialists.     

Xylem anatomy and calculated hydraulic conductance of four <Emphasis Type="Italic">Nothofagus</Emphasis> species with contrasting distribution in South-Central Chile

Nothofagus obliqua, N. dombeyi, N. alpina and N. antarctica are characteristic tree species of the temperate forests on the western slopes of the Andes with centres of distribution that differ in their temperature and moisture regimes. We tested branch wood from co-occurring specimens of these species for the inherent differences in xylem anatomy and theoretical hydraulic conductance to evaluate their resistance to drought or frost. The hydraulic conductivity of the xylem was calculated using a modified Hagen–Poiseuille equation and related to wood density. Conduit dimensions were used to predict the water potential that would cause 50 % loss of hydraulic conductivity (Ψ ₅₀). Nothofagus alpina, which mainly grows at sites with low frost frequency, exhibited the largest conduits and the highest mean values for conduit area, fraction of conduit area in the cross-section and hydraulic conductivity, but the lowest wood density. Opposite relationships were found in the plastic N. antarctica, whose xylem seems to be least vulnerable to freezing-induced, but also to drought-induced embolism. Calculated Ψ ₅₀ was highest (least negative) in N. alpina, indicating a relatively high susceptibility to cavitation. The xylem of the thermophilic N. obliqua and of N. dombeyi, which mainly occurs under oceanic climate, but can also survive at sporadically dry and warm sites, is not particularly adapted to periods of drought stress. Across all species, wood density was negatively correlated with the calculated hydraulic conductance. The xylem traits of N. alpina might contribute to its relatively high growth rate and facilitate its spread into forest gaps.     

Thermal constraints on foraging of tropical canopy ants

Small cursorial ectotherms risk overheating when foraging in the tropical forest canopy, where the surfaces of unshaded tree branches commonly exceed 50 °C. We quantified the heating and subsequent cooling rates of 11 common canopy ant species from Panama and tested the hypothesis that ant workers stop foraging at temperatures consistent with the prevention of overheating. We created hot experimental “sunflecks” on existing foraging trails of four ant species from different clades and spanning a broad range of body size, heating rate, and critical thermal maxima (CT_max). Different ant species exhibited very different heating rates in the lab, and these differences did not follow trends predicted by body size alone. Experiments with ant models showed that heating rates are strongly affected by color in addition to body size. Foraging workers of all species showed strong responses to heating and consistently abandoned focal sites between 36 and 44 °C. Atta colombica and Azteca trigona workers resumed foraging shortly after heat was removed, but Cephalotes atratus and Dolichoderus bispinosus workers continued to avoid the heated patch even after >5 min of cooling. Large foraging ants (C. atratus) responded slowly to developing thermal extremes, whereas small ants (A. trigona) evacuated sunflecks relatively quickly, and at lower estimated body temperatures than when revisiting previously heated patches. The results of this study provide the first field-based insight into how foraging ants respond behaviorally to the heterogeneous thermal landscape of the tropical forest canopy.     

Boreal peat properties link to plant functional traits of ecosystem engineers

Aims

Warming has the potential to alter plant litter mass loss and nutrient release during decomposition. However, a great deal of uncertainty remains concerning how other factors such as litter species or substrate quality might modify the effects of increased temperature on decomposition. Meanwhile, the temperature sensitivity of plant litter decay in tropical and subtropical forest ecosystems remains poorly resolved.

Methods

This study was designed to assess the effects of experimental warming on litter decomposition and nutrient release of two contrasting tree species (Schima superba and Machilus breviflora) by translocating model forest ecosystems from the high-elevation sites to the lower-elevation sites in subtropical China. Translocating model mountain evergreen broad-leaved forest (MEBF) to the altitude of 300 m and 30 m increased the average monthly soil temperature at 5 cm depth by 0.88 and 1.84 °C, respectively during the experimental period. Translocating model coniferous and broad-leaved mixed forest (CBMF) to the altitude of 30 m increased the average monthly soil temperature at 5 cm depth by 0.85 °C.

Results

We found that experimental warming accelerated litter decomposition in both model forest types, and the promoting efficiency was greater when the temperature increased. The litter with high quality (Schima superba) had stronger response to warming than low quality litter (Machilus breviflora). Warming accelerated Na, K, Mg, P, N and Ca release from Schima superba litter, but only simulated Ca release from Machilus breviflora litter. Overall, litter decomposition was controlled by the order: soil temperature > litter quality > soil moisture > litter incubation forest type under experimental warming in the subtropical China.

Conclusion

We conclude that leaf litter decomposition was facilitated by experimental warming in subtropical China. Litter species might modify the effects of increased temperature on litter decomposition; however, forest type has no effect on litter decomposition.

     

Interannual variation in rainfall,drought stress and seedling mortality may mediate monodominance in tropical flooded forests

Flood tolerance is commonly regarded as the main factor explaining low diversity and monodominance in tropical swamps. In this study we examined seedling mortality in relation to seasonality, i.e., flooding versus drought, of the dominant tree species (Prioria copaifera), and three associated species (Pterocarpus officinalis, Carapa guianensis and Pentaclethra macroloba), in seasonally flooded forests (SFF) in Darien, Panama. Seedling mortality differed among species, years and seasons. Prioria seedlings experienced the lowest overall mortality, and after 3 years many more Prioria seedlings remained alive than those of any of the associated species. In general, within species, larger seedlings had greater survival. Seed size, which can vary by close to 2 orders of magnitude in Prioria, had a confounding effect with that of topography. Large-seeded Prioria seedlings experienced 1.5 times greater mortality than small-seeded seedlings, as large-seeded Prioria seedlings were more likely to be located in depressions. This finding suggests that seed size, plant size and topography are important in understanding SFF regeneration. For all species, seedling mortality was consistently greater during the dry season than during flooding. For Prioria, dry season seedling mortality was correlated with drought stress, that is, high mortality during the long El Niño dry season of 1998 and the normal dry season of 2000, but very low dry season mortality during the mild dry season of 1999. Prioria’s ability to dominate in seasonally flooded forest of Central America is partly explained by its low drought-related mortality in comparison to associated species.     

Diversity,molecular phylogeny and fingerprint profiles of airborne <Emphasis Type="Italic">Aspergillus</Emphasis> species using random amplified polymorphic DNA

In the present study, diversity and phylogenetic relationship of Aspergillus species isolated from Tehran air was studied using random amplified polymorphic DNA (RAPD)–polymerase chain reaction (RAPD-PCR). Thirty-eight Aspergillus isolates belonging to 12 species i.e. A. niger (28.94 %, 11 isolates), A. flavus (18.42 %, 7 isolates), A. tubingensis (13.15 %, 5 isolates), A. japonicus (10.52 %, 4 isolates), A. ochraceus (10.52 %, 4 isolates), and 2.63 %, 1 isolate from each A. nidulans, A. amstelodami, A. oryzae, A. terreus, A. versicolor, A. flavipes and A. fumigatus were obtained by settle plate method which they were distributed in 18 out of 22 sampling sites examined. Fungal DNA was extracted from cultured mycelia of all Aspergillus isolates on Sabouraud Dextrose Agar and used for amplification of gene fragments in RAPD-PCR using 11 primers. RAPD-PCR data was analyzed using UPGMA software. Resulting dendrogram of combined selected primers including PM1, OPW-04, OPW-05, P160, P54, P10 and OPA14 indicated the distribution of 12 Aspergillus species in 8 major clusters. The similarity coefficient of all 38 Aspergillus isolates ranged from 0.02 to 0.40 indicating a wide degree of similarities and differences within and between species. Taken together, our results showed that various Aspergillus species including some important human pathogenic ones exist in the outdoor air of Tehran by different extents in distribution and diversity and suggested inter- and intra-species genetic diversity among Aspergillus species by RAPD-PCR as a rapid, sensitive and reproducible method.     

Fingerprinting by amplified fragment length polymorphism (AFLP) and barcoding by three plastidic markers in the genus <Emphasis Type="Italic">Wolffiella</Emphasis> Hegelm

Amplified fragment length polymorphism (AFLP) fingerprinting and three different plastidic DNA regions (rpl16, rps16, atpF-atpH) were used to investigate species identity in the genus Wolffiella. For this purpose, clones (67 in total) belonging to all ten species were selected. Almost all the species were represented by more than one clone. The fingerprinting technique, AFLP, clearly distinguished the species, W. caudata, W. gladiata, W. neotropica, W. rotunda, and W. welwitschii. Apart from confirming the molecular identity of these five species, the plastidic markers could delineate two additional species, W. hyalina and W. denticulata, although the conclusion concerning the latter is restricted by the availability of only one clone. The efficiency of the plastid-derived markers in identifying the number of species-specific clusters followed the sequence rps16 > rpl16 > atpF-atpH. The species W. lingulata, W. oblonga, and W. repanda could not be identified by any of the molecular methods presented here, but could be strictly defined on a morphological basis. In several clones, high amounts of genetic admixtures between different species were detected. Further, simulation studies demonstrated that these clones are genetic hybrids. This might be one of the obstacles in molecular identification of species in the genus Wolffiella.     

Can <Emphasis Type="Italic">Pinus</Emphasis> plantations facilitate reintroduction of endangered cloud forest species?

Coniferous plantations have been widely used by reforestation programs seeking to mitigate the effects of deforestation in mountainous areas in different parts of the world. However, some studies show that pine plantations can simulate natural mechanisms of succession, thereby facilitating the incorporation of other native species of mid- and late-successional stages. Existing pine plantations could function as a substitute habitat and facilitate the establishment of native and endangered cloud forest species. To test this hypothesis, we planted two endangered species from the family Juglandaceae (Juglans pyriformis and Oreomunnea mexicana) under twelve-year-old canopy plantations of Pinus patula and compared them to individuals planted in open (control) sites and recorded their survival and growth. The results show that the survival of J. pyriformis and O. mexicana was significantly higher below the canopy of P. patula plantations than in the open site. However, growth rates varied significantly among species and sites. Although pine plantations may favor the survival of seedlings, they cannot ensure the growth of plants without additional forest management.     

Effects of herbivory and mistletoe infection by <Emphasis Type="Italic">Psittacanthus calyculatus</Emphasis> on nutritional quality and chemical defense of <Emphasis Type="Italic">Quercus deserticola</Emphasis> along Mexican forest fragments

Mistletoes are parasitic plants that show effects that can parallel or contrast with those caused by herbivores to their host plants, particularly on aspects such as host biomass, resource allocation patterns, and interspecific interactions at the community level. In this study, we evaluated the potential synergistic effects of herbivory and infection by the mistletoe Psittacanthus calyculatus on nutritional quality and chemical defense of the white oak Quercus deserticola along forest fragments in Mexico. For this, we sampled leaves of parasitized oaks, unparasitized oaks and mistletoes at four forest fragments in the Cuitzeo basin, Michoacán state, Mexico, and measured herbivory levels and foliar water content, total nonstructural carbohydrates, phenols, flavonoids, and hydrolyzable tannins in each sample. Higher levels of infection by P. calyculatus were found in the smaller forest fragments, while foliar damage by herbivores was higher in larger forest fragments. At all sites, levels of herbivory were lower in the mistletoe than in both parasitized and unparasitized oaks. However, there was a positive relationship between herbivory levels in parasitized oaks and their mistletoes. Also, foliar water content and total phenol concentration were positively correlated between the oaks and the mistletoes. The results suggest that herbivory levels in parasitized hosts and mistletoes depend on the close physiological interaction between the nutritional quality and the chemical defense of the two plants involved. This is one of the few studies analyzing the chemical ecology of the interaction between plant hosts and plant parasites.     

Combined land cover changes and habitat occupancy to understand corridor status of Laljhadi-Mohana wildlife corridor,Nepal

Corridor design is a centripetal conservation tool to facilitate movement between fragmented patches. Increases in anthropogenic activity have caused degradation in forest connectivity, influencing animal movement to a small degree. Laljhadi-Mohana wildlife corridor (LMWC), a corridor between Shuklaphanta National Park (Nepal) and Dudhwa National Park (India) created to be used by Panthera tigris and Elephas maximus in western Nepal, is under pressure of anthropogenic change. Using current knowledge, we analyzed land cover changes (LCC) of LMWC between 2002 and 2012. We used ERDAS IMAGINE 9.2 and Arc GIS 9.2 to process satellite images, and occupancy survey to assess status of corridor. We classified land cover into dense forest, sparse forest, cultivation, water bodies, grassland, expose surfaces, and sand bank as structural attributes of the corridor. Our analysis found dense forest area was reduced by 18.35% in a decade while cultivation and sparse forest increased by 10.15% and 8.89%, respectively. Illegal forest encroachment, resource extraction, grazing pressure, invasive species, and flood were major drivers of forest change. The null occupancy model estimated the highest detection probability of Elephas maximus (0.48 ± 0.08) and the lowest of Axis axis (0.20 ± 0.08). Incorporating site covariates improved occupancy estimates of Sus scrofa (0.82), Axis axis (0.76), Elephas maximus (0.76), Boselaphus tragocamelus (0.66), and Panthera pardus (0.55). Distance to cultivation was the most influential covariate, supported by the expansion of cultivated land in the corridor. LMWC is a functional wildlife corridor despite a decline in forest cover. This decline influenced the number and detection rates of large mammals, instigating crop raiding and conflict. Mitigation measures on LCC drivers, particularly forest encroachment, can improve the functional status of LMWC and raise detection rates of large mammals in future studies.