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Regression of mapped territories against Thiessen polygons with respect to territory size (a, c) and the number of neighbours (b, d). Panels (a) and (b) show model estimates and confidence intervals (black), regressions for individual studies (grey) and the data frequency (parallel to the axes). The dotted line indicates a perfect fit. Axes in (a) are given as the percentage of the largest (log-transformed) value per study. Note that in contrast to the statistical model, the data shown here are non-centralized. Panels (c) and (d) show the slope of the respective regression depending on the distance of the focal point used for the construction of Thiessen polygons to the centroid of the mapped territory. Grey circles are individual estimates from the randomizations, and the black line is a smooth curve through the randomized points.
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Thiessen polygons are often used to model territory characteristics. However, information about the quality of Thiessen polygon-based estimates is currently lacking. We used published data to investigate the match between Thiessen polygons and mapped bird territories regarding territory size, shape and neighbourhood. Although territory sizes and th...
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... Modelling animal territoriality using Thiessen or Voronoi polygons dates to the studies by Tanemura (1976, 1980) and Adams (1998Adams ( , 2001, when geometrical models were built to estimate individual distribution and territory shape and size of territorial animals (reviewed by Schlicht et al., 2014)-not much dissimilar from studies on population dynamics and home-range estimation. ...
We explore the use of movable automata in numerical modelling of male competition for territory. We used territorial dragonflies as our biological inspiration for the model, assuming two types of competing males: (a) faster and larger males that adopt a face‐off strategy and repulse other males; (b) slower and smaller males that adopt a non‐aggressive strategy. The faster and larger males have higher noise intensity, leading to faster motion and longer conservation of motion direction. The velocity distributions resemble the Maxwell distributions of velocity, expected in Brownian dynamics, with two probable velocities and distribution widths for the two animal subpopulations. The fast animals' trajectories move between visually fixed density folds of the slower animal subpopulation. A correlation is found between individual velocity and individual area distribution, with smaller animals concentrated in a region of small velocities and areas. Attraction between animals results in a modification of the system behaviour, with larger animals spending more time being surrounded by smaller animals and being slowed down by their interaction with the surroundings. Overall, the study provides insights into the dynamics of animal competition for territory and the impact of attraction between animals.
... To model a territory distribution that most resembles the saturated situation at the start year of our model simulation (1986; see next section), we selected the census year that had the highest density and used the territory coordinates as midpoints for each territory (data in ref. 51). Next, we overlaid the territory midpoints with the spatial elevation map and used a Voronoi tessellation algorithm 63 to divide all grid cells on the islands among all breeding territories. ...
Sea-level rise will lead to widespread habitat loss if warming exceeds 2 °C, threatening coastal wildlife globally. Reductions in coastal habitat quality are also expected but their impact and timing are unclear. Here we combine four decades of field data with models of sea-level rise, coastal geomorphology, adaptive behaviour and population dynamics to show that habitat quality is already declining for shorebirds due to increased nest flooding. Consequently, shorebird population collapses are projected well before their habitat drowns in this UNESCO World Heritage Area. The existing focus on habitat loss thus severely underestimates biodiversity impacts of sea-level rise. Shorebirds will also suffer much sooner than previously thought, despite adapting by moving to higher grounds and even if global warming is kept below 2 °C. Such unavoidable and imminent biodiversity impacts imply that mitigation is now urgently needed to boost the resilience of marshes or provide flood-safe habitat elsewhere.
... We included study year and nest identity as random intercepts. Second, for extra-pair events involving locally breeding sires, we compared the distance between the nest of the extra-pair sire and the nest where he sired extra-pair young as the "neighborhood distance" [88], i.e., we assigned territory boundaries by calculating Thiessen polygons [129] and computed the neighborhood rank (i.e., direct neighbors = 1, second order neighbors = 2, etc.). ...
In animals, reproductive performance typically improves over time early in life. Several ultimate and proximate mechanisms may contribute to such an age-related improvement and these mechanisms can act in a relative or in an absolute sense. Low performance of young individuals may be the consequence of a comparison or competition with older individuals (relative), or it may be due to specific traits of young individuals and be unrelated to the presence of older competitors (absolute). Here, we perform a test to disentangle whether the effect of age class (yearling or older) on male extra-pair siring success is relative or absolute. Male age is the most consistent predictor of male extra-pair siring success across bird species, yet the mechanisms underlying this pattern are not well understood. Low extra-pair siring success of yearling males may be a consequence of the presence of older (“adult”) males (hypothesis 1), because adult males are more successful in intra- and intersexual interactions or because females prefer to copulate with adult males when available (relative preference). Alternatively, low extra-pair siring success of yearlings may be independent of the presence of adult males (hypothesis 2), for example, if yearling males on average invest less in extra-pair behavior or if females avoid them as extra-pair mates, independent of the availability of older males (absolute preference). To distinguish between these 2 hypotheses, we experimentally manipulated the age structure of a nest-box-breeding population of blue tits (Cyanistes caeruleus) by removing almost all adult males, and compared patterns of extra-pair paternity in the experimental year with those from the preceding 15 “control” years. Removal of adult males resulted in a substantial increase in the extra-pair siring success of yearling males compared to the “control” years, but did not affect the population-level frequency of extra-pair paternity or its spatial patterns. Our results provide clear evidence that extra-pair siring success of yearlings can increase and that it depends on the presence of older males in the population, indicating a relative effect of age on reproductive performance. These results suggest that older males outcompete yearling males in direct or indirect interactions, in sperm competition or as a result of differences in attractiveness to females.
... In order to label territorial neighbours during the spring, we used the spatial arrangement of occupied nest boxes to estimate individual territories and their boundaries. For each occupied box, a Voronoi diagram (Thiessen polygon) was drawn to include all of the points that were closer to the focal box than any other occupied box (Adams 2001;Schlicht et al. 2014). This method of estimating territories and neighbours accurately accounts for population density and is highly correlated with territory sizes and boundaries that are manually determined ...
The social environment has diverse consequences for individuals' welfare, health, reproductive success, and survival. This environment consists of different kinds of dyadic bonds that exist at different levels; in many social species, smaller social units come together in larger groups, creating multilevel societies. In great tits (Parus major), individuals have four major types of dyadic bonds: pair mates, breeding neighbours, flockmates, and spatial associates, all of which have been previously linked to fitness outcomes. Here, we show that these different types of dyadic bonds are differentially linked with subsequent reproductive success metrics in this wild population and that considering spatial effects provides further insights into these relationships. We provide evidence that more social individuals had a higher number of fledglings, and individuals with more spatial associates had smaller clutch sizes. We also show individuals with stronger bonds with their pair mate had earlier lay dates. Our study highlights the importance of considering different types of dyadic relationships when investigating the relationship between wellbeing and sociality, and the need for future work aimed at experimentally testing these relationships, particularly in spatially structured populations.
... Utilizing this grid simplified the process of functionally determining the degree of vulnerability in distinct Fujian coastal zones. Though the Thiessen polygon grid and other twodimensional delineation polygons were used in earlier research for studies on species habitats, waste management, and hydrology (Ikhumhen et al., 2020;Richter et al., 2019;Schlicht et al., 2014;Shen et al., 2012;Swannack et al., 2014), however, these studies have a number of shortcomings, including the Thiessen polygons' applicability to a broad assessment and their inability to offer a thorough view of the different influential regions. Hence, this study aims to create a 500 by 500-m grid polygon of the coast using the ArcGIS Fishnet grid tool, totaling 12,961 grid cells. ...
... 8 occupied box (Schlicht et al. 2014). We then classified individuals as first-order neighbors if they shared a territory boundary (see Supplementary Figure S3). ...
... We then classified individuals as first-order neighbors if they shared a territory boundary (see Supplementary Figure S3). Estimating territories and neighbors in this way within this and similar systems has previously been shown to be biologically meaningful in terms of population density and breeding success and to correlate with manually determined territory sizes and neighbors (Adams 2001;Wilkin et al. 2006;Grabowska-Zhang et al. 2012b;Schlicht et al. 2014). ...
The social interactions that an individual experiences are a key component of its environment and can have important consequences for reproductive success. The dear enemy effect posits that having familiar neighbors at a territory boundary can reduce the need for territory defense and competition and potentially increase cooperation. Although fitness benefits of reproducing among familiar individuals are documented in many species, it remains unclear to what extent these relationships are driven by direct benefits of familiarity itself versus other socioecological covariates of familiarity. We use 58 years of great tit (Parus major) breeding data to disentangle the relationship between neighbor familiarity, partner familiarity, and reproductive success while simultaneously considering individual and spatiotemporal effects. We find that neighbor familiarity was positively associated with reproductive success for females but not males, while an individual's familiarity with their breeding partner was associated with fitness benefits for both sexes. There was strong spatial heterogeneity in all investigated fitness components, but our findings were robust and significant over and above these effects. Our analyses are consistent with direct effects of familiarity on individuals' fitness outcomes. These results suggest that social familiarity can yield direct fitness benefits, potentially driving the maintenance of long-term bonds and evolution of stable social systems.
... The CMM markets and TDPEs are the key links in the TCM industrial chain. Thiessen polygons can quantify the scope of raw materials sold or purchased by CMM markets or TDPEs (Schulman et al., 2007;Schlicht et al., 2014). Generally, farmers are more likely to sell their medicinal plants to the nearest CMM market, disregarding, of course, price, traffic conditions, or other factors; moreover, TDPEs are more likely to buy raw materials from the nearest CMM market. ...
Medicinal plants are the primary material basis for disease prevention and treatment in traditional Chinese medicine (TCM). The conservation and sustainable utilization of these medicinal plants is critical for the development of the TCM industry. However, wild medicinal plant resources have sharply declined in recent decades. To ameliorate the shortage of medicinal plant resources, it is essential to explore the development potential of the TCM industry in different geographical regions. For this purpose, we examined the spatial distribution of commonly used medicinal plants in China, the number of Chinese medicinal material markets, and the number of TCM decoction piece enterprises. Specifically, multispecies superimposition analysis and Thiessen polygons were used to reveal the optimal range for planting bulk medicinal plants and the ideal regions for building Chinese medicinal material markets, respectively. Furthermore, we quantitatively analyzed mismatches between the spatial distribution of commonly used medicinal plant richness, Chinese medicinal material markets, and TCM decoction piece enterprises. We found four large areas in China suitable for growing commonly used medicinal plants: the Hengduan Mountain, Nanling Mountain, Wuling Mountain, and Daba Mountain areas. The Thiessen polygon network based on Chinese medicinal material market localities showed there are currently fewer markets in southwestern, northwestern, and northeastern China than in central and southern China. TCM decoction piece enterprises are concentrated in a few provinces, such as Hebei and Jiangxi. We found that the distribution of commonly used medicinal plants, Chinese medicinal material markets and TCM decoction piece enterprises are mismatched in Henan, Shaanxi, Hunan, Hubei, Zhejiang, Fujian, Chongqing, and Xizang. We recommend strengthening development of the TCM industry in Henan, Hunan, Zhejiang, Shaanxi, Hubei, Chongqing, Fujian, and Xizang; building more Chinese medicinal material markets in southwestern, northwestern, and northeastern China; and establishing medicinal plant nurseries in resource-rich provinces to better protect and domesticate local medicinal plants.
... To test whether magpies used caching territories, that is, an area where only the pair that owns the territory caches acorns and prevents other magpies from caching and recovering acorns (H1), we constructed a Voronoi polygon (VP) around each active nest in the next spring to assess whether the distributions of cached acorns coincided with these polygons. VPs are often used as a model for bird territory estimations (Adams, 2001;Schlicht et al., 2014). In spring 2016, after monitoring acorn dispersal, we located all active magpie nests (details in Supplementary Methods in Supporting Information;Figures S2 and S3). ...
For plants with seeds dispersed by scatter‐hoarders, decision‐making by animals when caching determines the spatial pattern of seed dispersal and lays the initial template for recruitment, driving the regeneration of many plant species. However, the mechanism by which animal behaviour shapes seed distributions in spatially complex landscapes is not well understood. We investigated caching territoriality and site preferences to determine the spatial pattern of seed caching at different scales and whether scatter‐hoarding behaviour drives the spatial distribution of seedling emergence.
We used radio‐tracking and automatic wildlife cameras to monitor holm oak (Quercus ilex) acorn caching by Eurasian magpies (Pica pica), who are effective scatter‐hoarders in agroforestry systems. We assessed the effect of caching territories, distance to seed source, habitat, sub‐habitat, microsites and caching material in the spatial pattern of acorn dispersal by magpies. In addition, we analysed the relationship between the density of cached acorns and of emerged seedlings in different habitats.
Breeding magpies cached the acorns inside their caching territories, where they preferred tilled areas over oak plantations and mostly avoided old fields. These differences in habitat preference were maximized at relatively short to medium dispersal distances, where most acorns were cached, and decreased or disappeared at long distances. Within tree plantations, magpies preferred high plant‐productivity sites over low productivity ones. At the finest spatial scale, magpies preferred structures built by animals, such as rabbit grit mounds and latrines and ant litter mounds, to cache the acorns. In many sites, magpies selected uncommon materials such as stones and litter to cover caches. In the subsequent spring, seedling emergence was positively correlated with acorn cache density.
Synthesis. Scatter‐hoarding is a hierarchical process in which caching sites are selected using different criteria at different spatial scales driven by territoriality and site preferences. Territoriality constrained dispersal distance and the habitats available for acorn caching. Magpie territoriality therefore indirectly drives oak seedling emergence and can determine oak recruitment and forest regeneration.
... Therefore, in a second approach we assigned trees to putative territories 228 . In order to avoid unrealistically large territories in low-density years and/or parts of 235 the area with low occupation, we set a maximum cut-off distance at either 25 or 35m 236 (Schlicht et al. 2014)). We did not include a lower cut-off distance (e.g. ...
Many studies have investigated how spring temperature affects laying dates and how this in turn affects the synchrony between nestling food demands and the insect food peak that follows tree budburst. While there is strong evidence that temperature itself acts as a cue for this plasticity in annual timing, the exact nature of the cue and response remains to be elucidated. Here we use long-term data on Great and Blue Tits and an unprecedented dataset on the location and phenology of 1396 trees to investigate whether small-scale variation in laying date can be explained by local tree phenology, and/or by tree species composition around nestboxes. Individual trees maintained their relative timing of budburst between years, while differences among tree species were more variable between springs. Contrary to expectation, we found no relation between first-egg dates and average budburst date at different distances around the nestbox. This can at least partly be explained by the very low degree of spatial autocorrelation in tree budburst. We did find an effect of local tree composition whereby Blue Tits, but not Great Tits, laid earlier in nestboxes surrounded by more oaks and fewer beeches. Although Blue Tit nest failure rate was higher in territories with more beech trees, independently of laying date, we found no evidence for preferential occupation of oak-dominated territories. Thus although we found some evidence for fine-scale effects of tree species on timing of breeding, the underlying mechanism remains unclear.
... We estimated the size of the breeding territory (in square meters) using the r package "expp" (Valcu and Schlicht 2013;Schlicht et al. 2015a). The package assigns each point in the study area to the nearest breeding pair, thereby creating distinct territories using Thiessen polygons (Valcu and Kempenaers 2010;Schlicht et al. 2014; see Supplementary Figure S1). We then calculated changes in territory size by dividing the size in year x + 1 by the size in year x (ratio). ...
Many studies investigated variation in the frequency of extrapair paternity (EPP) among individuals. However, our understanding of within-individual variation in EPP remains limited. Here, we comprehensively investigate variation in EPP at the within-individual level in a population of blue tits (Cyanistes caeruleus). Our study is based on parentage data comprising >10 000 genotyped offspring across 11 breeding seasons. First, we examined the repeatability of the occurrence of EPP, the number of extrapair offspring, the number of extrapair partners, and the occurrence of paternity loss using data from males and females that bred in multiple years. Second, we tested whether within-individual changes in EPP between breeding seasons relate to between-year changes in the local social environment. Repeatabilities were generally low but significant for the occurrence and number of extrapair young in females and for whether a male sired extrapair young or not. We found no evidence that the presence of the former social partner or changes in the proportion of familiar individuals or in phenotypic traits of the neighbors influenced changes in levels of EPP in females. However, in adult males, a decrease in the average body size of male neighbors was associated with higher extrapair siring success. If confirmed, this result suggests that the competitive ability of a male relative to its neighbors influences his extrapair mating success. We suggest that alternative hypotheses, including the idea that within-individual changes in EPP are due to “chance events” rather than changes in an individual’s social breeding environment, deserve more consideration.
