Field Census Research Articles

Estimating oil palm (Elaeis guineensis) production potential using Unmanned Aerial Vehicle

Abstract. Charloq, Thoha AS, Yazid A, Sidiq AM, Lubis OA. 2024. Estimating oil palm (Elaeis guineensis) production potential using Unmanned Aerial Vehicle. Biodiversitas 25: 2981-2989. The vast expanse of oil palm (Elaeis guineensis Jacq.) plantations utilized Unmanned Aerial Vehicle (UAV) technology, identified as a suitable tool for mapping the health condition and production potential of oil palm plants. A plant census was conducted to confirm the correct number of plants, utilizing GPS to record each plant's coordinates, assess its health status, and estimate its production potential. This study aimed to estimate oil palm production potential with maximum accuracy using drone technology over a 22.23-hectare plantation. The research method involved drone based mapping of plant numbers and health, thereby estimating the potential production of oil palm. Orthomosaic data processed using Oil Palm Analysis (OPA) software were analyzed and compared with field survey data (plant census) through the Student t test with ? = 5%. In conclusion, from the study of drone/UAV technology based estimation of oil palm (E. guineensis) production potential in the field on an area of 22.23 ha at PT. Eastern Indonesia Bukit Maradja Estate, North Sumatra Province, Indonesia, it can be concluded that the use of drone technology for oil palm production estimation through OPA is highly effective, with no significant discrepancies between drone results and traditional field census methods. This consistency confirms that UAVs are a reliable tool for assessing the production potential of oil palm plantations.

Nephila spider male aggregation: preference for optimal female size and web clustering.

Sexual size dimorphism theory predicts biased operational sex ratios (OSRs) and an uneven distribution of males among certain females. We studied this phenomenon through a field census of the giant wood spider Nephila pilipes (family Nephilidae) in Singapore, a species where females are, on average, 6.9 times larger than males. Specifically, we tested two hypotheses concerning male distribution, given their tendency to aggregate in certain female webs. The optimal female size hypothesis predicts that males would predominantly occupy webs of intermediate-sized females. The web clustering hypothesis posits that more males would be found in webs closer together compared to those farther apart. Our snapshot census revealed a female-biased OSR (females: males = 1.85) with an uneven distribution of males in female webs. Most males were found in webs of intermediate-sized females aligning with the optimal female size hypothesis. Proximity among female webs was indicative of male presence, lending support to the web clustering hypothesis. While our study's limited sample size warrants caution, we conclude that in N. pilipes, male occupation of female webs is facilitated by the clustering of webs, and males prefer to cohabit with optimally sized, receptive females.

Within-host adaptive speciation of commensal yoyo clams leads to ecological exclusion, not co-existence.

Symbionts dominate planetary diversity and three primary symbiont diversification processes have been proposed: co-speciation with hosts, speciation by host-switching, and within-host speciation. The last mechanism is prevalent among members of an extraordinary marine symbiosis in the Indian River Lagoon, Florida, composed of a host mantis shrimp, Lysiosquilla scabricauda, and seven host-specific commensal vasconielline "yoyo" clams (Galeommatoidea) that collectively occupy two distinct niches: burrow-wall-attached, and host-attached/ectocommensal. This within-host symbiont radiation provides a natural experiment to test how symbiont coexistence patterns are regulated in a common ancestral habitat. The competitive exclusion principle predicts that sister taxa produced by adaptive speciation (with distinct morphologies and within-burrow niches) are most likely to coexist whereas the neutral theory predicts no difference among adaptive and non-adaptive sister taxa co-occurrence. To test these predictions, we engaged in (1) field-censusing commensal species assemblages; (2) trophic niche analyses; (3) laboratory behavioral observations. Although predicted by both models, the field census found no mixed-niche commensal assemblages: multi-species burrows were exclusively composed of burrow-wall commensals. Their co-occurrence matched random assembly process expectations, but presence of the single ectocommensal species had a highly significant negative effect on recruitment of all burrow-wall commensal species (P<0.001), including on its burrow-wall commensal sister species (P < 0.001). Our stable isotope data indicated that commensals are suspension feeders and that co-occurring burrow-wall commensals may exhibit trophic niche differentiation. The artificial burrow behavioral experiment yielded no evidence of spatial segregation among burrow-wall commensals, and it was terminated by a sudden breakdown of the host-commensal relationship resulting in a mass mortality of all commensals unattached to the host. This study system appears to contain two distinct, superimposed patterns of commensal distribution: (1) all burrow-wall commensal species; (2) the ectocommensal species. Burrow-wall commensals (the plesiomorphic condition) broadly adhere to neutral theory expectations of species assembly but the adaptive evolution of ectocommensalism has apparently led to ecological exclusion rather than coexistence, an inverse outcome of theoretical expectations. The ecological factors regulating the observed burrow-wall/ectocommensal exclusion are currently obscure but potentially include differential recruitment to host burrows and/or differential survival in "mixed" burrow assemblages, the latter potentially due to changes in host predatory behavior. Resampling host burrows during commensal recruitment peak periods and tracking burrow-wall commensal survival in host burrows with and without added ectocommensals could resolve this outstanding issue.

Biovectoring of plastic by white storks from a landfill to a complex of salt ponds and marshes

Research into plastic pollution has extensively focused on abiotic vectors, overlooking transport by animals. Opportunistic birds, such as white storks (Ciconia ciconia) often forage on landfills, where plastic abounds. We assess plastic loading by ingestion and regurgitation of landfill plastic in Cadiz Bay, a major stopover area for migratory white storks in south-west Spain. On average, we counted 599 storks per day moving between a landfill and a complex of salt ponds and marshes, where they regurgitated pellets that each contained a mean of 0.47 g of plastic debris, dominated by polyethylene. Modelling reliant on GPS tracking estimated that 99 kg and >2 million particles of plastic were biovectored into the wetland during 2022, with seasonal peaks that followed migration patterns. GPS data enabled the correction of field censuses and the identification of plastic deposition hotspots. This study highlights the important role that biovectoring plays in plastic transport into coastal wetlands.

Biology of Patanga japonica (Orthoptera, Acrididae): Nymphal growth, host plants, reproductive activity, hatching behavior, and adult morphology

The biology of Patanga japonica (Bolívar, 1898), including seasonal nymphal growth, host plants, mating, oviposition, hatching, and adult morphology, was studied under outdoor and indoor conditions in central Japan. A field census showed that this grasshopper had a univoltine life cycle and overwintered in the adult stage. Body size was found to increase with a delay in the time of adult emergence in females but not in males, and protandry was observed. The insects were mainly associated with a few plant species. Feeding tests showed that at least one of the 5 test nymphs molted to the second stadium on 37 plant species, and more than 50% did so on 23 plant species. Mating was frequently observed in April and May under outdoor conditions, and the daily maximum number of copulating pairs was positively correlated with air temperature. Copulatory behavior, including stridulation, is described in detail. Oviposition was frequently observed in May and June under outdoor conditions. Larger females produced more eggs per pod, and a negative relationship was observed between egg lengths and the number of eggs per pod, showing a trade-off. On average, female adults had 124 ovarioles. Egg hatching occurred at different times during the daytime, but the eggs from each pod hatched synchronously. Synchronous hatching was also observed in eggs kept in groups of 2, 4, and 10, but hatching occurred earlier in larger group sizes. Eggs achieved synchronous hatching by either delaying or advancing hatching time. Two eggs separated by several millimeters hatched less synchronously than those kept in contact with one another. However, similarly separated eggs restored hatching synchrony when connected by thin wire, suggesting the involvement of vibrational signals in embryo–embryo communication. Morphometric analysis suggested that P. japonica adults change some morphometric ratios in response to crowding. Variation in pronotum shape was not significantly affected by crowding.

Effects of grazing on underground parts of marsh plants by wintering Middendorf's bean goose Anser fabalis middendorffii: Its role as a keystone species in plant communities

AbstractGeese are known to impact on the species composition and abundance of plant communities, with grazing pressure by flocks negatively affecting various aspects of vegetation and ecosystems. However, positive effects have also been highlighted, including grazing preventing competition among plants and helping to maintain a high level of biodiversity. The Middendorf's bean goose Anser fabalis middendorffii is one waterfowl that winters in the marsh lands of Japan. At the Katano‐kamoike pond, the species main wintering site in central Japan, the effects of goose grazing on the structure of marsh plant communities were investigated by using field observations and experiments. During observations of foraging behavior, A. fabalis middendorffii mainly foraged on underground parts of Zizania latifolia and Bolboschoenus fluviatilis, including rhizomes, roots, and tubers, at the marshlands of the pond. The field census showed the biomass of the underground parts was significantly reduced by A. fabalis middendorffii grazing during winter. Specifically, the biomass of rhizomes in Z. latifolia was drastically decreased. Data collected from exclosure experiments over 5 years suggested that grazing pressure regulated the overgrowth of B. fluviatilis and enhanced the abundance of Z. latifolia. Furthermore, a field census of marsh plants at the Shimofukuda reservoir, where there have been no A. fabalis middendorffii, confirmed that the absence of A. fabalis middendorffii was related to a decrease in the abundance and biodiversity of marsh plants. In the Katano‐kamoike pond, A. fabalis middendorffii may play a key role in maintaining plant diversity.

Challenges of mismatching timescales in longitudinal studies of collective behaviour.

How individuals' prior experience and population evolutionary history shape emergent patterns in animal collectives remains a major gap in the study of collective behaviour. One reason for this is that the processes that can shape individual contributions to collective actions can happen over very different timescales from each other and from the collective actions themselves, resulting in mismatched timescales. For example, a preference to move towards a specific patch might arise from phenotype, memory or physiological state. Although providing critical context to collective actions, bridging different timescales remains conceptually and methodologically challenging. Here, we briefly outline some of these challenges, and discuss existing approaches that have already generated insights into the factors shaping individual contributions in animal collectives. We then explore a case study of mismatching timescales-defining relevant group membership-by combining fine-scaled GPS tracking data and daily field census data from a wild population of vulturine guineafowl (Acryllium vulturinum). We show that applying different temporal definitions can produce different assignments of individuals into groups. These assignments can then have consequences when determining individuals' social history, and thus the conclusions we might draw on the impacts of the social environment on collective actions. This article is part of a discussion meeting issue 'Collective behaviour through time'.

Conservation genomics reveals fine-scale population structuring and recent declines in the Critically Endangered Australian Kuranda Treefrog

The Kuranda Treefrog occurs in tropical north-east Australia and is listed as Critically Endangered due to its small distribution and population size, with observed declines due to drought and human-associated impacts to habitat. Field surveys identified marked population declines in the mid-2000s, culminating in very low abundance at most sites in 2005 and 2006, followed by limited recovery. Here, samples from before (2001–2004) and after (2007–2009) this decline were analysed using 7132 neutral genome-wide SNPs to assess genetic connectivity among breeding sites, genetic erosion, and effective population size. We found a high level of genetic connectivity among breeding sites, but also structuring between the population at the eastern end of the distribution (Jumrum Creek) versus all other sites. Despite finding no detectable sign of genetic erosion between the two times periods, we observed a marked decrease in effective population size (Ne), from 1720 individuals pre-decline to 818 post-decline. This mirrors the decline detected in the field census data, but the magnitude of the decline suggested by the genetic data is greater. We conclude that the current effective population size for the Kuranda Treefrog remains around 800 adults, split equally between Jumrum Creek and all other sites combined. The Jumrum Creek habitat requires formal protection. Connectivity among all other sites must be maintained and improved through continued replanting of rainforest, and it is imperative that impacts to stream flow and water quality are carefully managed to maintain or increase population sizes and prevent genetic erosion.

Sex‐specific breeding phenologies in the North American deer mouse (Peromyscus maniculatus)

AbstractEffects of global climate change on population persistence are often mediated by life‐history traits of individuals, especially the timing of somatic growth, reproductive development, and reproduction itself. These traits can vary among age groups and between the sexes, a result of differential life‐history tactics and levels of lifetime reproductive investment. Unfortunately, the trait data necessary for revealing sex‐specific breeding behaviors and use of breeding cues over reasonably large geographic areas remain sparse for most taxa. In this study, we assembled and analyzed a new reproductive trait base for the North American deer mouse (Peromyscus maniculatus) from digitized natural history specimens and field censuses. We used the data to reconstruct sex‐specific breeding phenologies and their drivers within and among North American ecoregions. Male and female phenologies varied across the geographic range of this species, with discordance in timing and intensity being highest in regions of lower seasonality (and longer breeding seasons). Reliance on environmental variables as breeding cues also appeared to vary in a sex‐specific manner, being most similar for photoperiod and least similar for temperature (positive male response and negative female response); in addition, model validation indicated that phenological models generalized better for males than for females. Finally, our individual‐level trait data also show that male reproductive investment (quantified as relative testis size) varies across the vastly different abiotic and social (i.e., female breeding) contexts studied here. By harmonizing across a broad set of digital data resources, we demonstrate the potential to uncover drivers of phenological variation within species and inform global change predictions at multiple scales of biological organization.

Ecological Predictors of Pupal Survival in a Common North American Butterfly.

All holometabolous insects undergo a pupal life stage, a transformative period during which the insects are immobile and thus particularly vulnerable to both natural enemies and harmful abiotic conditions. For multivoltine species like the silver-spotted skipper [Epargyreus clarus (Cramer) (Lepidoptera: Hesperiidae)], which produces both diapausing and nondiapausing generations throughout much of its range, both the duration of the pupal stage and the ecological challenges faced by pupae can differ among generations. We conducted a set of field experiments to investigate the seasonal and annual variation in pupal mortality for E. clarus pupae experiencing different biotic and abiotic conditions. We also examined the behavioral and ecological factors influencing the construction and persistence of pupal shelters by prepupal larvae. Surprisingly, measures of both cumulative and daily pupal predation were significantly higher during the relatively short (10-14 d) nondiapausing (summer) generations, compared with the diapausing (winter) generations, despite a nearly 20-fold longer pupal duration recorded for the latter. Indirect evidence from field censuses suggested that this intergenerational difference in mortality was due to seasonal variation in consumption of pupae by generalist vertebrate predators. The presence of a shelter increased survival in summer, though not in winter, perhaps because winter pupae were likely to be buried under autumnal leaf litter, regardless of initial shelter status. When constructing their shelters, prepupal E. clarus larvae did not prefer host leaves over nonhost leaves, suggesting that induced preferences are unlikely to play an important role in this process. Despite finding marked differences in the decomposition rates of shelter leaves derived from host vs. nonhost plants, several lines of evidence suggest that these differences are unlikely to impact E. clarus pupal mortality during either the summer or winter generations.

Raccoon Predation on Foam Nests and Adults of the Forest Green Tree Frog (Zhangixalus arboreus: Rhacophoridae) in Central Japan

We examined predation of the forest green tree frog, Zhangixalus arboreus, as part of a two-year monitoring study of the frog's reproductive processes at four ponds in central Japan, performed by using field censuses and sensor cameras. During the period, we confirmed predation against arboreal foam nests by the common raccoon, Procyon lotor. We also found a carcass of a female adult frog with eggs and bitten ground foam nests, the signs of which were strongly suspected to indicate predation by raccoons. These results imply that invasion of Japanese forest areas by alien raccoons is becoming an increasingly serious threat to Z. arboreus through predation at various life stages of the frog. At this study site, however, the demographics of both the raccoon and Z. arboreus have not yet been examined. We need more field data to assess the long-term effects of predation pressure on the frog.

Differential performance of contrasting defensive traits of cocoons of two moth species against bird predation

AbstractPrey defensive traits against predators can be categorized into primary defense (avoiding detection) and secondary defense (avoiding attack after detection). There are trade‐offs between these two defensive traits, which consider the cost of defense. To quantify the predation avoidance efficacy of both defensive traits against common predators, we compared bird predation pressures and the corresponding avoidance measures of cocoons of two nettle moth species, which utilize contrasting avoidance strategies: Parasa lepida (investing predominantly in primary defense) and Monema flavescens (investing predominantly in secondary defense). Field censuses revealed that bird predation was the most significant mortality factor for both species. The survival rate of cocoons was significantly higher for M. flavescens than for P. lepida, although M. flavescens were more conspicuous than P. lepida. Measurement of prepupae (cocoon content) mass, and experiments on the feeding preferences of the prepupae of both species using chicks, confirmed a similar quantity and quality of both speciesʼ prepupae as prey items. Our results were explained by the advantage of cocoon hardness outweighing the disadvantage of cocoon conspicuousness. The predation behavior of wild birds suggested that they spent considerably longer handling than searching for cocoons, which accounted for their cocoon preference for P. lepida over M. flavescens in the context of optimal foraging theory. Our results suggested that secondary defense was more effective in reducing bird predation than primary defense in limacodid cocoons.

The potential role of an alien tree species in supporting forest restoration: Lessons from Shiretoko National Park, Japan

Restoring forests has recently received considerable attention in the context of sequestering carbon and supporting biodiversity. Although considering alien species as a tool for natural forest restoration still remains controversial, harnessing alien species when they are already present in an ecosystem might result in overall benefits for nature and society. In this study we evaluated whether the presence of an alien tree species supports or hinders the establishment of naturally regenerating forests in Shiretoko National Park, Japan. In particular, we focused on Larix kaempferi, which is widely present yet non-native to the region, and examined how this alien species affects two factors influencing the success of restoration: wind disturbance and deer herbivory. We examined the following effects of L. kaempferi plantations on natural regeneration: (1) the windbreak function for protecting native tree growth and (2) the nursery function to promote the regeneration of native tree saplings and seedlings under high herbivory pressure. We assessed tree height and regeneration, using large-scale remotely sensed data and terrestrial inventory data in five major vegetation types. We found that L. kaempferi plantations can protect native species from predominant winds. Additionally, L. kaempferi canopy cover promoted abundance and species richness in understory saplings and seedlings compared to other vegetation types such as primary and secondary forests, even under excessive browsing pressure. No regenerating L. kaempferi individuals were observed during the field census, suggesting the species is likely not invasive in our study system. The positive relationship between alien tree species and the regeneration of native tree assemblages emphasizes that existing alien species have the potential to act as nurse plants. Our findings imply that the presence of alien species can contribute to natural forest restoration by improving the local environmental conditions for native species in the short-term. Given the multiple ecological and social needs in our changing world, careful consideration is required to evaluate the long-term consequences of alien species. Especially in ecosystems in which alien species have already established, using their positive functions rather than swiftly eradicating them from the landscape might be beneficial for long-term restoration goals. We conclude that managers need to be aware of the context-dependency of alien species to make restoration more effective.

Digital biodiversity data sets reveal breeding phenology and its drivers in a widespread North American mammal.

Shifts in reproductive timing are among the most commonly documented responses of organisms to global climate change. However, our knowledge of these responses is biased towards taxa that are easily observable and abundant in existing biodiversity data sets. Mammals are common subjects in reproductive biology, but mammalian phenology and its drivers in the wild remain poorly understood because many species are small, secretive, or too labor-intensive to monitor. We took an informatics-based approach to reconstructing breeding phenology in the widespread North American deer mouse (Peromyscus maniculatus) using individual-level reproductive observations from digitized museum specimens and field censuses spanning >100yr and >45 degrees of latitude. We reconstructed female phenology in different regions and tested the importance of three environmental variables (photoperiod, temperature, precipitation) as breeding cues. Photoperiod and temperature were strong positive and negative breeding cues, respectively, whereas precipitation was not a significant predictor of breeding phenology. However, phenologies and the use of environmental cues varied substantially among regions, and we found evidence that these cueing repertoires are tuned to ecosystem-specific limiting conditions. Our results reiterate the importance of ecological context in optimizing reproduction and demonstrate how harmonization across biodiversity data resources allows new insight into phenology and its drivers in wild mammals.

The occurrence of muskrat Ondatra zibethicus in central and eastern Poland in the period 1996–2007

Muskrat, Ondatra zibethicus (L. 1766), is an introduced species to European fauna. It is widespread in Poland, however, signs of its decline were observed in the last decades. While most of the information on muskrat is based on questionnaires and bag record, in this paper results of field census for muskrat signs (tracks and faeces) at a total of 1554 sites are presented. Signs of muskrats were present at 19.5% of 1111 sites surveyed from 1996-1998, and at 5.3% of 413 sites surveyed in 2007. Muskrats inhabited mostly small and medium rivers in the western part of the study area. The decrease in the occurrence of the species over a study period is the best document by a significant reduction in the frequency of muskrat records at the 249 sites surveyed in 1996-1998 (present at 44% sites) and 2007 (7%). The decline of the muskrat population is most probably the effect of increasing predation by American mink Neovison vison.

Allometric constraints and competition enable the simulation of size structure and carbon fluxes in a dynamic vegetation model of tropical forests (LM3PPA‐TV)

Tropical forests are a key determinant of the functioning of the Earth system, but remain a major source of uncertainty in carbon cycle models and climate change projections. In this study, we present an updated land model (LM3PPA-TV) to improve the representation of tropical forest structure and dynamics in Earth system models (ESMs). The development and parameterization of LM3PPA-TV drew on extensive datasets on tropical tree traits and long-term field censuses from Barro Colorado Island (BCI), Panama. The model defines a new plant functional type (PFT) based on the characteristics of shade-tolerant, tropical tree species, implements a new growth allocation scheme based on realistic tree allometries, incorporates hydraulic constraints on biomass accumulation, and features a new compartment for tree branches and branch fall dynamics. Simulation experiments reproduced observed diurnal and seasonal patterns in stand-level carbon and water fluxes, as well as mean canopy and understory tree growth rates, tree size distributions, and stand-level biomass on BCI. Simulations at multiple sites captured considerable variation in biomass and size structure across the tropical forest biome, including observed responses to precipitation and temperature. Model experiments suggested a major role of water limitation in controlling geographic variation forest biomass and structure. However, the failure to simulate tropical forests under extreme conditions and the systematic underestimation of forest biomass in Paleotropical locations highlighted the need to incorporate variation in hydraulic traits and multiple PFTs that capture the distinct floristic composition across tropical domains. The continued pressure on tropical forests from global change demands models which are able to simulate alternative successional pathways and their pace to recovery. LM3PPA-TV provides a tool to investigate geographic variation in tropical forests and a benchmark to continue improving the representation of tropical forests dynamics and their carbon storage potential in ESMs.

Leaf trichomes in Metrosideros polymorpha can contribute to avoiding extra water stress by impeding gall formation.

Plants inhabiting arid environments tend to have leaf trichomes, but their adaptive significance remains unclear. Leaf trichomes are known to play a role in plant defence against herbivores, including gall makers. Because gall formation can increase water loss partly through increased surface area, we tested the novel hypothesis that leaf trichomes could contribute to avoiding extra water stress by impeding gall formation, which would have adaptive advantages in arid environments. We focused on Metrosideros polymorpha, an endemic tree species in the Hawaiian Islands, whose leaves often suffer from galls formed by specialist insects, Hawaiian psyllids (Pariaconus spp.). There is large variation in the amount of leaf trichomes (0-40 % of leaf mass) in M. polymorpha. Three gall types are found on the island of Hawaii: the largest is the 'cone' type, followed by 'flat' and 'pit' types. We conducted laboratory experiments to quantify the extent to which gall formation is associated with leaf water relations. We also conducted a field census of 1779 individuals from 48 populations across the entire range of habitats of M. polymorpha on the island of Hawaii to evaluate associations between gall formation (presence and abundance) and the amount of leaf trichomes. Our laboratory experiment showed that leaf minimum conductance was significantly higher in leaves with a greater number of cone- or flat-type galls but not pit-type galls. Our field census suggested that the amount of trichomes was negatively associated with probabilities of the presence of cone- or flat-type galls but not pit-type galls, irrespective of environmental factors. Our results suggest that leaf trichomes in M. polymorpha can contribute to the avoidance of extra water stress through interactions with some gall-making species, and potentially increase the fitness of plants under arid conditions.

Effects of systemic insecticides on the population dynamics of the dragonfly Sympetrum frequens in Japan: Statistical analyses using field census data from 2009 to 2016

Since the mid-1990s, populations of the common Japanese dragonfly Sympetrum frequens in rice fields have declined severely. Application of systemic insecticides—especially fipronil—to nursery boxes of rice seedlings is suspected to be the main cause of the decline. However, until now there have been insufficient population data to test the causality. We conducted a dragonfly survey from 2009 to 2016 in four prefectures of Japan and compiled the data to enable the comparison of population growth rates along five main census routes over the years. We also estimated the use ratio of each insecticide applied to nursery boxes in rice fields (i.e., the area exposed to insecticide as a ratio of the total rice field area) by prefecture. We then statistically analyzed the effects of the insecticides on the dragonfly’s population growth rates, taking into account the potential confounding factors based on current knowledge. There was a significant negative association between the annual increase in use ratio of the sum of systemic insecticides (e.g., fipronil, imidacloprid, and chlorantraniliprole) and the annual population growth rate of S. frequens. This association suggests that systemic insecticide use affected the decrease in population density of the dragonfly, although some agronomic factors need to be further examined as potential confounders.

Multiplicity and complexity of food environment in China: full-scale field census of food outlets in a typical district.

Community food environment is closely associated with residents' health status, and it has received substantial research attention in recent years. However, such studies are sparse in China. This study aims to reveal the characteristics of food environment in China. A ground-truthing field census of food outlets was conducted in Xi Hu district, Hangzhou. A novel categorizing system was developed to better characterize food outlets in the study area. Geocoding and food environment analysis were performed by Arc-GIS software. A total of 9274 food outlets were identified, of these, 6161 (66.43%) were food service places and 3113 (33.57%) were food stores. Fast-food restaurants (2692) and convenience stores (1764) were the two most numerous outlet types. The density of food outlets was 29.72/km2 and 113.97/10,000 people. Availability of BMI-unhealthy food outlets was four times greater than that of BMI-healthy ones. Further, 41.86% of total food outlets provided food-delivery services; among them, fast-food restaurants were the highest (65.53%) providers. In the urban area, the average density of food outlets was 104/km2. While, it was only 29/km2 in the rural area. Availability of food outlets was excellent in our study area, though it showed regional imbalance. Food environment tends to be obesogenic and high prevalence of food delivery service might increase this trend. Thus, policy makers should guarantee the smooth development of catering industry in China, so as to ensure a balanced nutrition environment.

SURVIVAL OF PINUS WASHOENSIS (PINACEAE) FOLLOWING FIRE ON BABBITT PEAK, SIERRA COUNTY, CALIFORNIA

The Cottonwood Fire consumed about 185 square kilometers in the Tahoe and Toiyabe National Forests near Loyalton and Sierraville, CA in 1994. The wildfire reached a population of one of the rarest pines in North America, Pinus washoensis H.Mason & Stockw. (Washoe pine), in the Babbitt Peak Research Natural Area (RNA). A field survey and census was conducted in 1996 to find, map, and count living and dead P. washoensis individuals, and to assess the effects of the fire on the population. Although the fire reached most of the P. washoensis stands, 763 living reproductive individuals were found and less than 5.2% mortality was observed. The fire's intensity declined as it crossed the Bald Mountain ridge and mostly consumed understory vegetation and litter in the P. washoensis stands. The fire had the potential to devastate or eliminate this rare population, but instead, a combination of stochastic, vegetative, and topographic controls spared the P. washoensis stands and appears to have had beneficial effects for this population. All age classes of P. washoensis except seedlings were found in the Bald Mountain Range. The lack of seedlings is surprising because the two years between fire and survey had high precipitation. No sign of hybridization with other yellow pine species was evident. While it is promising that the stands of this rare pine survived the Cottonwood Fire, prospects for the continued persistence of this population are not good until there is a reproductive year that provides many recruits.