Negative Spatial Association Research Articles

Mycorrhizal Types Regulate Tree Spatial Associations in Temperate Forests: Ectomycorrhizal Trees Might Favour Species Coexistence.

In temperate mixed forests, dominant ectomycorrhizal (EM) tree species usually coexist with diverse arbuscular mycorrhizal (AM) understorey tree species. Here, we investigated the spatial associations between AM and EM trees in two > 20 ha temperate forest mega-plots to better understand the observed 'EM-dominant versus AM-diverse' coexistence. Overall, we found that positive spatial associations (e.g., facilitation) were mostly related to EM trees, while negative spatial associations (e.g., inhibition) were mainly related to AM trees. Because adult EM trees tended to facilitate surrounding AM and EM saplings and other EM adults in these two forests, facilitation hotspots that stabilize AM-EM tree coexistence should be centred around EM tree species rather than around AM tree species. Together, we propose a novel EM-stabilization mechanism, which emphasises how, despite some species-specific variation, EM tree species foster 'EM-dominant versus AM-diverse' coexistence in temperate mixed forests by facilitating other trees.

Competition and density dependence in arid mountain forest stands: revealing the complex process from spatial patterns

Understanding the spatial patterns and interaction of trees is crucial for exploring forest dynamics. However, limited research has explored the spatial pattern and interactions between adult trees and their offspring population in arid mountain forest ecosystems. We investigated the spatial distribution and interaction of recruitment, survival, and mortality at different size classes in the Populus davidiana forest in the Luoshan Mountains (Ningxia, China), to gain insights into its stand dynamics. (1) This demonstrated the characteristic shift from an aggregated to random distribution as seedlings grew and developed into adult trees. (2) The adult trees exhibited strong positive and weak negative spatial associations with seedlings and saplings, respectively, with an increasing spatial scale, yet both stages underwent stark transitions from negative (1–15 m scales) to positive (> 20 m scale) associations. (3) Generally, the closer the individual trees were to each other, the greater the negative impact of neighboring trees on the size of an individual tree. (4) Additionally, adult trees strongly increased the risk of seedling mortality across the spatial scale of 0–50 m. (5) Live seedlings were less than the dead ones around dead seedlings. There was a stronger aggregation of dead seedlings than live seedlings. Moreover, the density-dependent mortality in our study rejected the random mortality hypothesis. In summary, these results suggest that spatial separation occurs between dead and live seedlings of P. davidiana. Under adult trees, negative dependence plays an important role in the arid mountain forest recruitment. Our findings will contribute to the restoration and conservation of arid mountain forests and provide theoretical support for forest management.

Spatial patterns of prematurity and its determinants in the metropolitan region of São Paulo, Brazil, 2010-2019.

To analyze spatial distribution of preterm births and their association with maternal, social, and health services indicators in the metropolitan region of São Paulo, Brazil, 2010-2019. Ecological study using data on preterm newborns from 39 municipalities in the metropolitan region of São Paulo. Univariate global Moran's index (Im) was used to evaluate spatial association of prematurity, and univariate local Moran's index by using the cluster map (LISA) to identify spatial patterns and clusters. Bivariate global Moran's index was also used to analyze spatial autocorrelation with maternal, social, and health services indicators. A total of 3,103,898 live births were registered in period 2010-2019, of which 331,174 (10.7%) were preterm. The global Moran's index showed spatial independence (Im=0.05; p-value=0.233) of the proportion of preterm births between municipalities. However, in the local spatial analysis it was possible to identify a statistically significant spatial cluster between the municipalities of Biritiba Mirim, Guararema and Salesópolis, with high proportions of preterm births. In the bivariate analysis, a significant positive spatial association was identified with proportions of mothers under 20 years old (Im=0.17; p-value=0.024) and mothers with low schooling (Im=0.17; p-value=0.020), and a significant negative spatial association with HDI (Im=-0.14; p-value=0.039). The local spatial approach identified a spatial cluster located in the far east of the metropolitan region of São Paulo, where actions by health managers are needed to minimize occurrence of preterm births.

Within-field spatial patterns of Helicoverpa zea (Lepidoptera: Noctuidae) and spatial associations with stink bugs and their injury in field corn.

The corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), is a cosmopolitan pest in the field crop landscape in the southeastern United States. Field corn (Zea mays L.) is the most important midseason host for H. zea where intensive selection pressure occurs for resistance to insecticidal toxins from Bacillus thuringiensis (Bt). Because spatial patterns of H. zea in field corn have not been extensively studied, field corn was sampled for H. zea larvae and injury in 2021 and 2022. Patterns of spatial aggregation were identified in a number of fields in both larval populations and injury. Aggregation of H. zea larvae was less common at R5 than at R2. Associations between the spatial patterns of H. zea and the variability in crop phenology were identified in some fields, with positive associations between plant height and H. zea larvae, indicating that ovipositing H. zea moths avoid areas with reduced plant height and delayed reproductive maturity. Additionally, negative spatial associations between stink bug ear injury and H. zea larvae and their injury were found in a small number of cases, indicating some spatial interactions between the two pest complexes and their injury. Results from these studies provide valuable insight into the spatial patterns of H. zea in field corn. An understanding of the local dispersal and population dynamics of H. zea can be used to help further improve integrated pest management and insect resistance management programs for this major polyphagous pest.

Spatial Distribution of Pinus koraiensis Trees and Community-Level Spatial Associations in Broad-Leaved Korean Pine Mixed Forests in Northeastern China.

Investigating the spatial distributions and associations of tree populations provides better insights into the dynamics and processes that shape the forest community. Korean pine (Pinus koraiensis) is one of the most important tree species in broad-leaved Korean pine mixed forests (BKMFs), and little is known about the spatial point patterns of and associations between Korean pine and community-level woody species groups such as coniferous and deciduous trees in different developmental stages. This study investigated the spatial patterns of Korean pine (KP) trees and then analyzed how the spatial associations between KP trees and other tree species at the community level vary in different BKMFs. Extensive data collected from five relatively large sample plots, covering a substantial area within the natural distribution range of KP in northeastern China, were utilized. Uni- and bivariate pair correlation functions and mark correlation functions were applied to analyze spatial distribution patterns and spatial associations. The DBH (diameter at breast height) histogram of KP trees in northeastern China revealed that the regeneration process was very poor in the Changbai Mountain (CBS) plot, while the other four plots exhibited moderate or expanding population structures. KP trees were significantly aggregated at scales up to 10 m under the HPP null model, and the aggregation scales decreased with the increase in size classes. Positive or negative spatial associations were observed among different life stages of KP trees in different plots. The life history stages of the coniferous tree group showed positive spatial associations with KP saplings and juvenile trees at small scales, and spatial independence or negative correlations with larger KP trees at greater scales. All broad-leaved tree groups (canopy, middle, and understory layers) exhibited only slightly positive associations with KP trees at small scales, and dominant negative associations were observed at most scales. Our results demonstrate that mature KP trees have strong importance in the spatial patterns of KP populations, and site heterogeneity, limited seed dispersal, and interspecific competition characterize the spatial patterns of KP trees and community-level spatial associations with respect to KP trees, which can serve as a theoretical basis for the management and restoration of BKMFs in northeastern China.

Interactions between carnivore species: limited spatiotemporal partitioning between apex predator and smaller carnivores in a Mediterranean protected area

BackgroundThere is need of information on ecological interactions that keystone species such as apex predators establish in ecosystems recently recolonised. Interactions among carnivore species have the potential to influence community-level processes, with consequences for ecosystem dynamics. Although avoidance of apex predators by smaller carnivores has been reported, there is increasing evidence that the potential for competitive-to-facilitative interactions is context-dependent. In a protected area recently recolonised by the wolf Canis lupus and hosting abundant wild prey (3 ungulate species, 20–30 individuals/km2, together), we used 5-year food habit analyses and 3-year camera trapping to (i) investigate the role of mesocarnivores (4 species) in the wolf diet; (ii) test for temporal, spatial, and fine-scale spatiotemporal association between mesocarnivores and the wolf.ResultsWolf diet was dominated by large herbivores (86% occurrences, N = 2201 scats), with mesocarnivores occurring in 2% scats. We collected 12,808 carnivore detections over > 19,000 camera trapping days. We found substantial (i.e., generally ≥ 0.75, 0–1 scale) temporal overlap between mesocarnivores—in particular red fox—and the wolf, with no support for negative temporal or spatial associations between mesocarnivore and wolf detection rates. All the species were nocturnal/crepuscular and results suggested a minor role of human activity in modifying interspecific spatiotemporal partitioning.ConclusionsResults suggest that the local great availability of large prey to wolves limited negative interactions towards smaller carnivores, thus reducing the potential for spatiotemporal avoidance. Our study emphasises that avoidance patterns leading to substantial spatiotemporal partitioning are not ubiquitous in carnivore guilds.

Nexus between health poverty and climatic variability in Pakistan: a geospatial analysis

Studies investigating the interconnection of health poverty and climatic variability are rare in spatial perspectives. Given the importance of sustainable development goals 3, goal 10, and goal 13, we explored whether the geographic regions with diverse climate structure has a spatial association with health poverty; whether spatial disparities exist across districts of Pakistan. We implied the A-F methodology to estimate the MHP index using the PSLM survey, 2019–20. The climate variables were extracted from the online NASA website. We applied the spatial techniques of Moran’s I, univariate and bivariate LISA, to address the research questions. The findings revealed that the magnitude of MHP differs across districts. Punjab was found to be the better-ff whereas Baluchistan was the highest health poverty-stricken province. The spatial results indicated positive associations of MHP and climate indicators with their values in the neighbors, whereas a negative spatial association was found between the MHP and climate indicators. Also, spatial clusters and outliers of higher MHP were significant in Baluchistan and KP provinces. Government intervention and policymaker’s prioritization are needed towards health and health-related social indicators, mainly in the high poverty-stricken districts, with high temperature and low humidity and precipitation rates, especially in Baluchistan.

CD8 + T cell infiltration is associated with improved survival and negatively correlates with hypoxia in clear cell ovarian cancer

Unlike other histological types of epithelial ovarian carcinoma, clear cell ovarian carcinoma (CCOC) has poor response to therapy. In many other carcinomas, expression of the hypoxia-related enzyme Carbonic anhydrase IX (CAIX) by cancer cells is associated with poor prognosis, while the presence of CD8 + tumor-infiltrating lymphocytes (TIL) is positively prognostic. We employed [18F]EF5-PET/CT imaging, transcriptome profiling, and spatially-resolved histological analysis to evaluate relationships between CAIX, CD8, and survival in CCOC. Tissue microarrays (TMAs) were evaluated for 218 cases in the Canadian COEUR study. Non-spatial relationships between CAIX and CD8 were investigated using Spearman rank correlation, negative binomial regression and gene set enrichment analysis. Spatial relationships at the cell level were investigated using the cross K-function. Survival analysis was used to assess the relationship of CAIX and CD8 with patient survival for 154 cases. CD8 + T cell infiltration positively predicted survival with estimated hazard ratio 0.974 (95% CI 0.950, 1000). The negative binomial regression analysis found a strong TMA effect (p-value < 0.0001). It also indicated a negative association between CD8 and CAIX overall (p-value = 0.0171) and in stroma (p-value = 0.0050) but not in tumor (p-value = 0.173). Examination of the spatial association between the locations of CD8 + T cells and CAIX cells found a significant amount of heterogeneity in the first TMA, while in the second TMA there was a clear signal indicating negative spatial association in stromal regions. These results suggest that hypoxia may contribute to immune exclusion, primarily mediated by effects in stroma.

Plant-plant co-occurrences under a complex land-use gradient in a temperate forest.

Land-use generates multiple stress factors, and we need to understand their effects on plant-plant interactions to predict the consequences of land-use intensification. The stress-gradient hypothesis predicts that the relative strength of positive and negative interactions changes inversely under increasing environmental stress. However, the outcome of interactions also depends on stress factor's complexity, the scale of analysis, and the role of functional traits in structuring the community. We evaluated plant-plant co-occurrences in a temperate forest, aiming to identify changes in pairwise and network metrics under increasing silvopastoral use intensity. Proportionally, positive co-occurrences were more frequent under high than low use, while negative co-occurrences were more frequent under low than high. Networks of negative co-occurrences showed higher centralization under low use, while networks of positive co-occurrences showed lower modularity and higher centralization under high use. We found a partial relationship between co-occurrences and key functional traits expected to mediate facilitation and competition processes. Our results shows that the stress-gradient hypothesis predicts changes in spatial co-occurrences even when two stress factors interact in a complex way. Networks of negative co-occurrences showed a hierarchical effect of dominant species under low use intensity. But positive co-occurrence network structure partially presented the characteristics expected if the facilitation was an important mechanism characterizing the community under high disturbance intensity. The partial relationship between functional traits and co-occurrences may indicate that other factors besides biotic interactions may be structuring the observed negative spatial associations in temperate Patagonian forests.

Facilitation in plants shifts along a recovery gradient induced by long‐term overgrazing in a temperate steppe community

AbstractQuestionsPlant facilitation often dominates over competition in stressful environments. However, to our knowledge few studies have examined plant facilitation within the context of herbivore pressure. Herbivory‐induced is a classic example of indirect facilitation. For example, in the temperate steppe region of Inner Mongolia, China, the intensive grazing by domestic animals has induced widespread grassland degradation. Here, we ask whether such long‐term overgrazing leads to facilitation in plants.LocationXilingol steppe region, Inner Mongolia, China.MethodsWe examined the spatial structure of three dominant plant species, including two species that are palatable to sheep (Leymus chinensis and Agropyron michnoi) and one that is unpalatable (Stipa grandis). We examined whether the spatial aggregation of these three species provided evidence for facilitation by comparing their spatial patterns along a recovery gradient: high grazing pressure (HG), an eight‐years grazing exclusion (early‐stage recovery from grazing; ER), and a 21‐years grazing exclusion (late‐stage recovery; LR). To accomplish this, we used the bivariate pair‐correlation function, g12(r), to assess the spatial association between unpalatable and palatable species. A positive spatial association indicates that facilitation dominates over competition (or dispersal limitation, habitat heterogeneity). We used a null model to assess the significance of spatial associations. Furthermore, we evaluated intraspecific spatial aggregation with the g11(r) by combining to three null models at fine spatial scales.ResultsThe spatial association between palatable and unpalatable species suggests a hump‐shaped relationship along the gradient of the grazing exclusion time. Specifically, Leymus chinensis and Stipa grandis showed a neutral, positive and negative association across the three stages of natural recovery from 21 years of grazing exclusion to current grazing. Similarly, Agropyron michnoi and Stipa grandis showed a negative, very positive and positive spatial association along the same gradient. Moreover, intraspecific spatial aggregation was higher in the current grazing treatment than in the grazing exclusion treatment. This was particularly true at the finest spatial scales (i.e., &lt;0.2 m).ConclusionsOur results suggest that facilitation between and within species along the recovery gradient in steppe communities is related to herbivore pressure induced by long‐term overgrazing. First, we observed no evidence of indirect facilitation between species in current grazing treatment, while direct facilitation between plant species appears strongest at early stages of natural recovery along the gradient of the grazing exclusion time. Moreover, we observed indirect intraspecific facilitation dominated in the current grazing treatment, especially at small scales across the same gradient.

Spatial response of hard- and mixed-bottom benthic epifauna to organic enrichment from salmon aquaculture in northern Norway

Norwegian Atlantic salmon aquaculture is continuing to expand in northern regions dominated by hard- and mixed-bottom substrates. Such habitats contain rich benthic epifaunal communities, including sponges and other sessile invertebrates susceptible to the impacts of particulate material released from finfish farms. Here, conventional soft-sediment sampling techniques are unable to discern the impacts of farm waste, and new monitoring methods and indicator taxa must be identified. This study improves understanding of the impacts of particulate waste released from salmon farms on the density and structure of benthic epifaunal communities on mixed- and hard-bottom substrates. The diversity, density, and composition of epifaunal communities and visually conspicuous benthic infauna were recorded in towed camera transects along the enrichment gradient (~50-800 m) of 3 salmon farms in northern Norway. Elevated fluxes of particulate material in the vicinity of all farms significantly affected epifaunal community composition, as did the coverage of some key substrate types. The defecated mounds of lugworms and the seastar Asterias rubens were notably more abundant near the farms where fluxes were elevated. The sponges Polymastia spp. and Phakellia spp. and the soft coral Duva florida showed significant declines in density with increasing sedimentation and were principal taxa in communities at natural sedimentation levels. Results identify taxa with both positive and negative spatial associations to particulate waste released from finfish farms and the potential for the development of an epifauna indicator-based index for monitoring the environmental impacts of aquaculture in hard- and mixed-bottom dominated substrates.

Spatial analysis of dengue incidence and Aedes aegypti ovitrap surveillance in Belo Horizonte, Brazil.

Understanding the intra-urban spatial dynamics of Aedes aegypti and dengue transmission is important to effectively guide vector control. Ovitraps are a sensitive, cost-effective vector surveillance tool, yet few longitudinal studies have evaluated ovitrap indices and dengue occurrence. We aimed to assess the spatial patterns of dengue incidence and Ae.aegypti ovitrap positivity index (OPI) over time and to examine the spatial relationship between these two variables. This study used 12years (2007-2018) of dengue case records and biweekly Ae.aegypti ovitrap data in Belo Horizonte, Brazil. We aggregated data by year and health centre catchment area (n=152) and used both univariate and bivariate global Moran's I statistic and LISA to evaluate spatial clustering. Annual dengue incidence ranged from 18 to 6262/100000 residents and displayed spatial autocorrelation in 10/12years, with shifting areas of high incidence. Annual OPI ranged from 35.7 to 47.6% and was clustered in all study years, but unlike dengue had consistent spatial patterns over time. Bivariate analysis found both positive (6/12years) and negative (1/12years) spatial associations between the two variables. Low detected presence of Ae.aegypti was not a limiting factor in dengue transmission. However, stable spatial distribution of OPI suggests that certain areas may have persistent breeding sites. Future research should identify factors related to persistent Ae.aegypti hotspots to better guide vector management. Vector control efforts should be paired with additional data on population immunity, circulating serotypes and urban factors to better predict and control outbreaks.

Spatial association between the incidence rate of COVID-19 and poverty in the São Paulo municipality, Brazil.

In this article, we investigated the spatial dependence of the incidence rate by COVID-19 in the São Paulo municipality, Brazil, including the association between the spatially smoothed incidence rate (INC_EBS) and the social determinants of poverty, the average Salary (SAL), the percentage of households located in slums (SLUMS) and the percentage of the population above 60 years of age (POP>60Y). We used data on the number notified cases accumulated per district by May 18, 2020. The spatial dependence of the spatially smoothed incidence rate was investigated through the analysis of univariate local spatial autocorrelation using Moran's I. To evaluate the spatial association between the INC_EBS and the determinants SAL, POP>60Y and SLUMS, we used the local bivariate Moran's I. The results showed that the spatially smoothed incidence rate for COVID-19 presented significant spatial autocorrelation (I = 0.333; P<0.05), indicating that the cases were concentrated in clusters of neighbouring districts. The INC_EBS showed a negative spatial association with SAL (I = -0.253, P<0.05) and POP>60Y (I = -0.398, P<0.05). We also found that the INC_EBS showed a positive spatial association with households located in the slums (I = 0.237, P<0.05). Our study concluded that the households where the population most vulnerable to COVID-19 resides were spatially distributed in the districts with lower salaries, higher percentages of slums and lower percentages of the population above 60 years of age.

Ecological niche overlap between co-occurring native and exotic ungulates: insights for a conservation conflict

Exploitative competition implies an indirect interaction in which a resource exploited by one species is not available for another; e.g., when species share diet or habitat. It plays a key role in community structure and dynamics. Here we evaluated the niche overlap between the exotic aoudad (Ammotragus lervia) and the native Iberian ibex (Capra pyrenaica) where the species coexist in the Iberian Peninsula, along two main dimensions, the trophic niche and the environmental niche. Then we assessed the spatial segregation of the species. We expected that if a niche overlap was high, competition could drive spatial segregation to allow co-existence. We analyzed their trophic niche overlap by using the content of stable isotopes δ15N and δ13C in the hair of both species. To establish environmental niche competition, we compared the similarity in their habitat, estimated by environmental niche models based on the fine-scale presence records of each species obtained from field surveys. To test if spatial segregation occurred, we analyzed both species’ co-occurrence. Our results indicated that both species shared a similar trophic niche measured by stable isotopes, both species showed a similar distribution of suitable areas, and that both species’ environmental niches were more similar than expected. Finally, a negative spatial association was found between the aoudad and Iberian ibex. These results reveal that both species are ecologically similar and suggest that fine-scale spatial segregation might have favoured their co-existence in semiarid Mediterranean mountains. Our results show that integrating information on trophic and environmental niche overlap with fine scale spatial distribution might improve the study of competitive interactions among wild ungulates.

Positive associations among rare species and their persistence in ecological assemblages.

According to the competitive exclusion principle, species with low competitive abilities should be excluded by more efficient competitors; yet, they generally remain as rare species. Here, we describe the positive and negative spatial association networks of 326 disparate assemblages, showing a general organization pattern that simultaneously supports the primacy of competition and the persistence of rare species. Abundant species monopolize negative associations in about 90% of the assemblages. On the other hand, rare species are mostly involved in positive associations, forming small network modules. Simulations suggest that positive interactions among rare species and microhabitat preferences are the most probable mechanisms underpinning this pattern and rare species persistence. The consistent results across taxa and geography suggest a general explanation for the maintenance of biodiversity in competitive environments.

Bird's nest ferns promote resource sharing by centipedes

AbstractBird's nest ferns (Asplenium spp.) support large numbers of invertebrates, including centipedes. As top invertebrate predators, centipedes drive ecosystem function, for example, by regulating decomposer populations, but we know little of their ecology in forest canopies. We provide the first detailed observations of the diversity and structure of the centipede communities of bird's nest ferns, revealing the importance of these epiphytes as nurseries for centipedes. We collected 305 centipedes equating to ˜11,300 mg of centipede biomass from 44 bird's nest ferns (22 of which were from the high canopy and 22 from the low canopy) in primary tropical rainforest in Sabah, Malaysian Borneo. Most abundant were the Scolopendromorpha (n = 227 individuals), followed by the Geophilomorpha (n = 59), Lithobiomorpha (n = 14), and Scutigeromorpha (n = 5). Although we observed very little overlap in species between the forest strata, scolopendromorph centipedes dominated throughout the canopy. Null model analysis revealed no significant competitive interactions; on the contrary, we observed centipedes sharing nest sites within the ferns on three of the ten occasions that we found nests. All nests belonged to centipedes of the family Scolopendridae, which are typically aggressive, and usually show negative spatial association. This study reveals a diverse community of canopy centipedes, providing further evidence of the importance of bird's nest ferns to a wide range of animals, many of which use the ferns at critical life stages. Future conservation strategies should regard these ubiquitous epiphytes as umbrella species and protect them accordingly in landscape management decisions.Abstract in Malay is available with online material.

Epidemiological and space-time analysis of Beijing Intestinal Infectious Diseases

Epidemiological and space-time analysis of Beijing Intestinal Infectious Diseases

Spatial association of fruit yield of Bertholletia excelsa Bonpl. trees in eastern Amazon

Brazil nut (Bertholletia excelsa) is one of the most important non-timber forest product (NTFP) species in the world. Better management and conservation practices will only be possible with an in-depth knowledge of tree species ecology. This study aimed to assess the spatial association of fruit yield of Bertholletia excelsa (B. excelsa) trees in two forest types (old growth terra firme forest and Amazon-cerrado transitional forest) in the Brazilian Amazon. Fruit yield was measured in both forest types during 2010. At each forest type, fruit yield was divided into different yield classes (number of fruits) for subsequent spatial modeling. The bivariate Ripley’s K-function was applied to quantify the spatial association of fruit yield of B. excelsa trees over different fruit yield classes. The results revealed that the forest type influences the spatial association of B. excelsa fruit yield. The old growth terra firme forest presented random spatial association for fruit yield, which implies that fruit yield of B. excelsa trees in this forest type is not limited by tree location and site resources. On the other hand, the Amazon-cerrado transitional forest presented significant negative spatial association for fruit yield across different yield classes, which means that under some conditions fruit yield of a given tree influences the fruit yield of the neighboring tree in this forest type. Site resources in the Amazon-cerrado transitional forest is limited and naturally favors inter- and intra-specific competition. Finally, the results imply the need for adoption of different management and conservation strategies for B. excelsa in different forest types in the Brazilian Amazon.

Assessing ecosystem service provision in a tropical region with high forest cover: Spatial overlap and the impact of land use change in Amapá, Brazil

Ecosystem service (ES) assessments have flourished globally in recent years and are now frequently used by policymakers and environmental managers. However, data scarce regions continue to be less well studied, limiting the comprehensiveness of the approach and its potential benefits. Here we aim to assess multiple ES and their spatial relationships in a region with high tropical forest cover, the state of Amapá, in the Brazilian Amazon. We develop a simple method to measure nine ES, identify spatial associations between them, and explore the impact of land use change on the capacity of forests to provide those services. The ES analysed include biodiversity, regional climate regulation, indigenous heritage, agricultural production, and NTFP extraction. Both negative (n = 20) and positive (n = 12) spatial associations are found, with agricultural land and forests having the highest total ES provision. We also show that this varies nonlinearly with distance to forest edges. In the face of currently unavoidable data scarcities in high biodiversity tropical areas, we show that this approach can provide useful evidence for land use management decisions.

When do we have the power to detect biological interactions in spatial point patterns?

Uncovering the roles of biotic interactions in assembling and maintaining species‐rich communities remains a major challenge in ecology. In plant communities, interactions between individuals of different species are expected to generate positive or negative spatial interspecific associations over short distances. Recent studies using individual‐based point pattern datasets have concluded that (a) detectable interspecific interactions are generally rare, but (b) are most common in communities with fewer species; and (c) the most abundant species tend to have the highest frequency of interactions. However, it is unclear how the detection of spatial interactions may change with the abundances of each species, or the scale and intensity of interactions. We ask if statistical power is sufficient to explain all three key results.We use a simple two‐species model, assuming no habitat associations, and where the abundances, scale and intensity of interactions are controlled to simulate point pattern data. In combination with an approximation to the variance of the spatial summary statistics that we sample, we investigate the power of current spatial point pattern methods to correctly reject the null model of pairwise species independence.We show the power to detect interactions is positively related to both the abundances of the species tested, and the intensity and scale of interactions, but negatively related to imbalance in abundances. Differences in detection power in combination with the abundance distributions found in natural communities are sufficient to explain all the three key empirical results, even if all pairwise interactions are identical. Critically, many hundreds of individuals of both species may be required to detect even intense interactions, implying current abundance thresholds for including species in the analyses are too low. Sy n thesis. The widespread failure to reject the null model of spatial interspecific independence could be due to low power of the tests rather than any key biological process. Since we do not model habitat associations, our results represent a first step in quantifying sample sizes required to make strong statements about the role of biotic interactions in diverse plant communities. However, power should be factored into analyses and considered when designing empirical studies.