Interspecific and intraspecific variation in diet preference in five Atlantic forest dung beetle species

1. Dung beetles are commonly assumed to be generalist feeders, but there has been limited work in identifying whether there is interspecific variation in feeding preference. Equally, there has been no work exploring whether generalist feeding behaviour in a species is a result of within‐species specialisation. 2. This study identified the individual and species‐level feeding preferences of five dung beetle species towards human, jaguar and pig dung using a choice experiment. 3. It was found that species varied in their preference for the dung types, but there was no evidence that within a species, individual beetles varied in their dung choice. These findings were similar to results from field experiments that are more typically used to assess feeding preferences in dung beetles. 4. The results suggest that individual specialism in feeding may not be common in dung beetles. However, there is variation in feeding preferences among species, which is often overlooked and can have implications for the ecosystem functions they provide. It is suggested that choice arenas can be used to assess feeding preferences in dung beetle species that are not abundant enough to reliably estimate dietary choice from field studies.     

Exploring the relationship between NDVI and African elephant population density in protected areas

Assessing the extent to which populations are limited by bottom‐up processes driven by food limitation is crucial to our understanding of how ecosystems should be managed. Using satellite‐derived Normalised Difference Vegetation Index (NDVI) as an index of resource availability, we investigated the relationships between greenness levels and African elephant (Loxodonta africana) population densities. Our results unveiled a positive relationship between NDVI and elephant densities in nonforest populations, but failed to capture any significant effects of survey area and type, number of years after the continental poaching ban and the IUCN category of the protected area in which the survey was undertaken. The number of forest elephant populations for which density estimates were available was very low, and no significant relationship between NDVI and forest elephant density could be established. Altogether, our study suggests that NDVI can successfully be linked to megaherbivore abundance across Africa and further highlights that a continental approach to energy–abundance relationships can be conducted in a relatively low‐cost manner and short timescale, supporting managers' efforts to identify future suitable areas for elephant populations.     

The use of an unoccupied aerial vehicle to survey shark species over sand and rocky-reef habitats in a marine protected area

Cabo Pulmo National Park was established in 1995 and has since seen a large increase in fish biomass. An unoccupied aerial vehicle (UAV) was used to survey shallow coastal habitat in which lemon sharks (Negaprion brevirostris), bull sharks (Carcharhinus leucas) and Pacific nurse sharks (Ginglymostoma unami) were recorded. Sharks were more common in the afternoon, potentially using warmer shallow areas to behaviourally thermoregulate. This study highlights UAV surveying to be a viable tool for species identification, a limitation of previous terrestrial surveys conducted in the area.     

Disentangling the effects of area, energy and habitat heterogeneity on boreal forest bird species richness in protected areas

Aim  One of the few general laws in ecology is that species richness is a positive function of area. However, it has been proposed that area would merely be a proxy for energy. Additionally, habitat heterogeneity has been found to be an important factor determining species richness. Yet the relative importance of those relationships is little known, and it is still unclear how they are brought about. We aimed to dissect which factors drive the species richness of boreal forest birds, and to identify the most probable mechanisms.
Location  Forested protected areas in Finland.
Methods  Using bird line census data collected in 104 protected areas, we ran simultaneous autoregressive models to explain the species richness of forest birds. We explored the value of forest area, tree volume, tree growth, mean degree days and habitat heterogeneity as explanatory variables and used the species richness within different species groups, based on the predictions of hypothesized mechanisms, as a response variable.
Results  Energy, rather than area or habitat heterogeneity, seems to be the main driver of species richness in boreal forest birds. More specifically, productive energy was a better predictor of total species richness than solar energy. Among the tested hypothetical mechanisms, the sampling hypothesis received strong support. After accounting for sampling, solar energy had an effect on species richness.
Main conclusions  As productive energy, such as tree volume, is associated with species richness, high-energy areas should be prioritized in forest conservation planning. Reductions in productive energy may first lead to the disappearance of the rarest species due to the random sampling process. Climate change may result in increased species richness due to increasing amount of productive and solar energy in forests. However, the range shifts of bird species may not be fast enough to keep up with the temperature increases.     

Land use history, plant rarity, and protected area adequacy in an intensively managed forest landscape

Assessment of biodiversity representation by protected areas mostly uses biological information to prioritise unrepresented features. Use of socio-economic factors (e.g. land use, ownership) is less prominent, even though they influence biodiversity distribution and reserve implementation. In regions with little protection, socio-economic factors may be more sensitive to prioritising risk among unprotected features: many biological priorities will exist but not all are threatened by land use. In an intensively managed region of New Brunswick, Canada, we conducted an ecosystem-based representation assessment and prioritised the unprotected elements with a combined biological and socio-economic ranking criteria. Biological data were the distribution and rarity of at-risk plants. Socio-economic data described land use intensity. Ecosystem units were fine-scale polygons resolved across topographical and edaphic gradients. We asked: 1) how adequately are units with rare plant hotspots protected? and 2) what are the relative risks to unprotected units from land use? Nineteen of twenty-eight ecosystems were preserved inadequately. Based on the combined ranking procedure, however, not all were equally at-risk. High risk units with rare plant hotspots were fertile, of gentle slopes or bottomlands, privately owned, and agriculture-dominated. Rare plants were concentrated in highly isolated forest remnants. Low risk units were infertile, poorly drained or topographically rugged, and owned by government or the forest industry; some contained rare plants but were well protected. Several unprotected and disturbed units were not ranked highly due to biological data base inconsistencies, and due to the weighting of the ranking criteria itself. Such problems, common to representation analyses, were highlighted by our use of multiple ranking criteria; affected units will require supplemental risk assessment. Our results indicate that high risk ecosystems will be difficult to protect because of habitat conversion and mostly private ownership. At the same time, socio-economic impacts, driven by forestry, appear to be shifting away from ecosystems now considered high priority. Tracking shifts in socio-economic pressure may anticipate future biodiversity impacts indiscernible using assessments based on species presently at-risk.     

Seasonality in elephant dung decay and implications for censusing and population monitoring in south-western Cameroon

Dung decay rates have been used in the past to correct elephant dung counts to estimates of population numbers. These assume that the dung is in a ‘steady state’ where production rates are equal to disappearance rates. The inter‐seasonal variation in decay rates, however, has never been fully investigated for elephant dung. This study, in the Banyang‐Mbo Wildlife Sanctuary in SW Cameroon, investigated whether a single dung decay rate is really appropriate when converting dung counts to population density estimates. A total of 870 fresh elephant dung‐piles were monitored until they had completely decayed, with at least 60 fresh dung piles located each month of the year between July 1994 to June 1995. The elephant dung decay rate obtained was 55.6% to 66.7% lower than those obtained for the rainforests of Gabon. This has implications for using decay rates obtained elsewhere to compute elephant densities from dung counts. Statistically significant differences were found in the mean duration of dung‐piles between different months and different seasons. Environmental variables, with the exception of rainfall, did not aid in predicting the duration of elephant dung‐piles. The model of Plumptre & Harris was used to estimate the standing crop of dung at any particular time of the year. The results show that, if there was no emigration of elephants from the population, then there was only a three‐month period when the dung was in a ‘steady state’. If emigration occurred during the wet season as is thought to occur then there was no period of ‘steady state’.     

Small-scale plant species richness in calcareous grasslands determined by the species pool, community age and shoot density

Variation in small-scale plant species richness was examined between twenty discrete sites of calcareous alvar grasslands in the western Estonian coastal area. This community type is very species rich at the small-scale. The pattern of diversity has often been explained by variation in ecological conditions which makes it possible to avoid competitive exclusion. Here we test an alternative species pool hypothesis. The species pool was defined as the set of species present in a community, but excluding all those species whose presence may be connected with exceptional environmental conditions for this community. Monte Carlo modelling was used to determine the strengths of the relationships between the non-independent variables: richness vs species pool and average shoot density vs richness. Site age was characterized by its elevation above sea level, since there is a continuous land uplift in the study area. Species richness was positively correlated to the size of the species pool, community age and vegetation density. We conclude that historical processes on both the regional and local levels, which determine the arrival of any particular species to a target community, and not environmental heterogeneity, are responsible for the variations in species richness between communities of this type.     

Estimate of leaf area index in an old-growth mixed broadleaved-Korean pine forest in northeastern China

Leaf area index (LAI) is an important variable in the study of forest ecosystem processes, but very few studies are designed to monitor LAI and the seasonal variability in a mixed forest using non-destructive sampling. In this study, first, true LAI from May 1(st) and November 15(th) was estimated by making several calibrations to LAI as measured from the WinSCANOPY 2006 Plant Canopy Analyzer. These calibrations include a foliage element (shoot, that is considered to be a collection of needles) clumping index measured directly from the optical instrument, TRAC (Tracing Radiation and Architecture of Canopies); a needle-to-shoot area ratio obtained from shoot samples; and a woody-to-total area ratio. Second, by periodically combining true LAI (May 1(st)) with the seasonality of LAI for deciduous and coniferous species throughout the leaf-expansion season (from May to August), we estimated LAI of each investigation period in the leaf-expansion season. Third, by combining true LAI (November 15(th)) with litter trap data (both deciduous and coniferous species), we estimated LAI of each investigation period during the leaf-fall season (from September to mid-November). Finally, LAI for the entire canopy then was derived from the initial leaf expansion to the leaf fall. The results showed that LAI reached its peak with a value of 6.53 m(2) m(-2) (a corresponding value of 3.83 m(2) m(-2) from optical instrument) in early August, and the mean LAI was 4.97 m(2) m(-2) from May to November using the proposed method. The optical instrument method underestimated LAI by an average of 41.64% (SD = 6.54) throughout the whole study period compared to that estimated by the proposed method. The result of the present work implied that our method would be suitable for measuring LAI, for detecting the seasonality of LAI in a mixed forest, and for measuring LAI seasonality for each species.     

Small-scale dynamics of plant communities in an experimentally polluted and fungicide-treated subarctic birch-pine forest

Pollution from the Cu-Ni smelter at Monchegorsk, Kola peninsula, has resulted in major changes in the plant communities surrounding the smelter. However, very little pollution reaches northern Finland, which makes it possible to use this area for field experiments to study the mechanism of community change under pollution load. A field experiment was established to study the possible effect of pollution on the subarctic forest community, with Cu-Ni pollution and acid rain (AR) used as treatments. A fungicide (F)-treatment was also added to estimate the significance of plant-fungus interactions in community response. Floristic similarity decreased during the experiment, both within and between treatments. Cu-Ni- and AR-treatments did not have any effect on species richness. The Cu-Ni treatment reduced significantly the number of new species arrivals in plots, whereas the number of local extinctions remained constant. The heavy metal treatment resulted in a decrease in the bryophyte cover. The cover of Linnea borealis increased slightly due to the Cu-Ni-treatment, but decreased due to the AR-treatment. The F-treatment also resulted in a lower richness than in the untreated variant. Again, this effect was due to the reduced number of arrivals, whereas the number of local extinctions remained unchanged. The F-treatment also resulted in a higher cover of bryophytes and dwarf shrubs. Changes in species richness of subarctic understorey plant communities were mainly caused by the differential arrival of species under different environmental conditions. As the number of arrivals was negatively correlated to the F-treatment, the presence of (presumably positive) interactions between vascular plants and fungi may have an influence on the response of a community to pollution.     

Seed predation patterns favor the regeneration of dominant species in forest gaps compared with the understory in an oak-pine mixed forest

Recent studies have demonstrated the higher likelihood of regeneration in forest gaps compared with the understory for the dominant species in pine-oak mixed forest. Here, we tested whether rodent seed predation or dispersal was beneficial for gap regeneration. We tracked the seed predation and dispersal of Quercus aliena var. acuteserrata and Pinus armandii using coded plastic tags in the forest understory close to gaps. Our results demonstrated that the proportions of initial buried seeds of both species were significantly more abundant in the forest understory compared with gaps. After seed caching, however, significantly lower proportions of the seeds of both species survived in the forest understory compared with gaps during the 30-day observation period. The final survival proportions of the seeds cached in the forest understory were lower than those cached in the gaps the next spring, which indicated that small rodents rarely retrieved scatter-hoarded seeds from forest gaps. Our findings suggest that rodent seed predation patterns contribute to the regeneration of the dominant species in gaps compared with the understory in a pine-oak mixed forest. In the study area, reforestation usually involves planting seedlings but direct sowing in forest gaps may be an alternative means of accelerating forest recovery and successional processes.     

林冠结构和地形对亚热带常绿落叶阔叶林林下幼苗物种多样性和功能多样性的影响

森林结构和地形是森林生态系统最明显的特点,也是影响林下幼苗存活和物种多样性的关键因子。该研究采用半球面摄影方法提取八大公山生长监测样地（共1.2 hm²）林冠结构参数,通过调查地表层木本植物幼苗的组成和多度,获取常见植物幼苗叶片功能性状,结合详细的地形信息,利用空间同步自回归模型探究林冠结构变量及地形因子对幼苗物种多样性及功能多样性的影响。结果表明：（1）八大公山亚热带山地常绿落叶阔叶林林冠结构复杂度较高,最大林冠高的平均值达到19.94 m,叶面积指数、平均叶倾角和林冠覆盖度分别为2.94、30.88°和0.87;（2）林冠结构变量和地形因子能够解释32.6%~48.4%的林下幼苗物种多样性指数变异和28.5%~70.2%的功能多样性变异,但地形因子对幼苗物种多样性的影响很小;（3）预测在亚热带常绿落叶阔叶林高海拔的山坡上,有较低的叶面积指数和平均叶倾角群落有较高的幼苗物种多样性;而在低海拔山脊上,较低的叶面积指数和平均叶倾角群落林下幼苗层有较高的功能多样性。此结果对科研人员和林业工作者开展野外森林更新情况评估和样方调查将有所帮助。     

Ecosystem functioning in relation to species identity,density, and biomass in two tunneller dung beetles

1. Species abundance, biomass, and identity are the main factors that influence ecosystem functioning. Previous studies have shown that community attributes and species identity help to maintain natural ecosystem functioning. 2. This study examined how species identity, biomass, and abundance in dung pats (i.e. density) of dung beetles affect multiple ecological functions: dung removal, seed dispersal, and germination. Specifically, two species of tunnellers were targeted: Onthophagus illyricus (Scopoli, 1763) and Copris lunaris (Linnaeus, 1758). In accordance with their natural abundance, densities ranging from 10 to 80 individuals were considered for O. illyricus, and those from two to eight were considered for C. lunaris, spanning the total biomass per treatment from 0.22 to 1.76 g. 3. Results showed that, even at higher abundance, O. illyricus is not as efficient as C. lunaris. These results show that species identity, biomass, and density are crucial factors for maintaining ecosystem functioning. The combined effect of species identity and density/biomass facilitated dung removal and seed dispersal. Conversely, species identity is the only relevant factor for germination. Moreover, relationships among functions depend on the species investigated: C. lunaris showed a positive correlation between dung removal and seed dispersal, whereas O. illyricus showed a positive correlation between germination and dung removal. 4. In conclusion, optimal ecosystem functioning depends on multiple factors, such as density and species identity, and thus also on body size, nesting strategies and ecological functions investigated. Moreover, the loss of larger and efficient species cannot be compensated by higher abundances of small species.     

Mammal indicator species for protected areas and managed forests in a landscape conservation area of northern India

There is a realization that managed forests and other natural areas in the landscape matrix can and must make significant contributions to biodiversity conservation. Often, however, there are no consistent baseline vegetation or wildlife data for assessing the status of biodiversity elements across protected and managed areas for conservation planning, nor is there a rapid and efficient means to acquire those data. We used a unified vegetation classification and simple animal sampling design to describe the patterns of abundance of selected mammals as indicator, or characteristic, species in different vegetation types and protected areas vs. managed forest units in the Terai Conservation Area (TCA) in northern Uttar Pradesh state, India. We quantified the relative abundance of 15 mammals of conservation concern from dung counts in vegetation sampling plots within 122 sample patches in 13 vegetation types and 4 management units. Assemblages of species differed both among vegetation types and among management units. Species assemblages in the two protected areas differed strongly from those in two managed forests. Grasslands in protected areas were the most species diverse among vegetation types and had several indicator species. Protected forests were dominated by chital (Axis axis) and nilgai (Boselaphus tragocamelus) in a second species group. A third species group in open grasslands and savannas in managed forests was characterized by cattle (Bos taurus) and Indian hare (Lepus nigricollis). Protected areas clearly are the core conservation area of the TCA for their relatively high habitat value and species diversity, and their protected status minimizes human disturbance. Impacts of human use are high in managed forests, indicating their compromised value for biodiversity conservation. Our simple assessment methodology gives managers a simple way to assess the status of important mammals across landscape conservation units.     

Edge effects on dung beetle assemblages in an Andean mosaic of forest and coffee plantations

In landscapes dominated by agriculture, conspicuous edges often occur between landscape elements. However, there is disagreement about the existence and intensity of edge effects, and information about species‐specific responses remains scarce. Studying such edge effects can help elucidate functional landscape connectivity and contribute to agricultural management. We, therefore, assessed whether sun‐grown coffee represents a barrier to dung beetles in an Andean agricultural landscape. We also evaluated whether the response to edge effects differs among species. We found that diversity and abundance tend to decrease from forest to sun‐grown coffee and that there are sharp increases in species turnover at the forest–coffee edge. We detected several different species‐specific responses to the forest–coffee edge, suggesting differences in the mobility of the species (or spillover) and in the degree of penetration that takes place from forest patches to sun‐grown coffee plantations. This study demonstrates that the sun‐grown coffee matrix constitutes a barrier to forest species and suggests that the forest–coffee ecotone is more complex than expected. Our results support the notion that the conservation value of native forest patches in agricultural scenarios depends on the functional connectivity of forest units in the landscape to maximize the opportunities species have to disperse through the agricultural matrix.     

Tree species distribution in canopy gaps and mature forest in an area of cloud forest of the Ibitipoca Range,south-eastern Brazil

The tree community of both canopy gaps and mature forest was surveyed in a 5 ha plot of cloud forest in the Ibitipoca Range, south-eastern Brazil, aiming at: (a) comparing the tree community structure of canopy gaps with that of three strata of the mature forest, and (b) relating the tree community structure of canopy gaps with environmental and biotic variables. All saplings of canopy trees with 1–5 m of height established in 31 canopy gaps found within the plot were identified and measured. Mature forest trees with dbh 3 cm were sampled in four 40×40 quadrats laid on the four soil sites recognised in the local soil catena. All surveyed trees were identified, measured and distributed into three forest strata: understorey (<5 m of height), sub-canopy (5.1–15 m) and canopy (15.1–30 m). The following variables were obtained for each gap: mode of formation, age, soil site, slope grade, size, canopy openness and abundance of bamboos and lianas. A detrended correspondence analysis indicated that the tree community structure of gaps in all soil sites was more similar to that of the mature forest understorey, suggesting that the bank of immatures plays an important role in rebuilding the forest canopy and that gap phases may be important for understorey shade-tolerant species. There was evidence of gap-dependence for establishment for only one canopy tree species. Both canonical correspondence analysis and correlation analysis demonstrated for a number of tree species that the distribution of their saplings in canopy gaps was significantly correlated with two variables: soil site and canopy openness. The future forest structure at each gap is probably highly influenced by both the present structure of the adjacent mature forest and the gap creation event.     

Population density and species composition of moss-living tardigrades in a boreo-nemoral forest

This study investigates for the first time the tardigrade fauna in a variety of different mosses from a coniferous forest and an adjacent clear-cut area in southern Sweden. Tardigrades were found in a majority of the samples. Sixteen species were recorded, of which the cosmopolitan species Macrobiotus hufelandi was the far most common. Some mosses, particularly species with "wefts" growth form, contained more tardigrades than other mosses, indicating that growth form may have an impact on tardigrade abundance. Mosses of the same species collected from a forest and from a clear-cut, respectively, did not show a general trend in the overall abundance of tardigrades, but the forest tended to contain more species. Five species of tardigrades ( Murrayon dianae, Isohypsibius sattleri, Platicrista angustata, Diphascon belgicae and Diphascon pingue ) never previously reported from Sweden were recorded.