Tree Canopy Cover Research Articles

Pursuit of environmental justice in urban forest planning and practice

IntroductionThere is a growing demand for urban forest management that prioritizes genuine community involvement, acknowledges power imbalances within society, and embraces the principles of environmental justice. To assess current initiatives and share better/best approaches, examining how environmental justice principles are applied in urban forest planning and practice is crucial. This study aims to understand the perspectives of urban foresters on the factors that either facilitate or impede the attainment of environmental justice goals.MethodsInterviews were conducted with urban foresters from non-profit organizations and municipal government in San Francisco, California, and Seattle, Washington. The interviewees were asked to identify and discuss their tree planting and maintenance strategies, public engagement protocol, and inter-organizational collaboration processes. To provide a contextual understanding of environmental injustice in the study cities, the historical racist practice of neighborhood redlining was examined alongside current tree canopy cover, locations of environmental hazards, and the spatial distribution of persons of color and those living in poverty.ResultsThe findings revealed that urban forestry professionals in each city approached environmental justice in distinct yet complementary ways: San Francisco prioritized distributional justice, while Seattle focused on elements of procedural and recognitional justice. The Race and Social Justice Initiative in Seattle and Proposition E in San Francisco have been instrumental in identifying and addressing inequities in urban forest planning and practice.Discussion/conclusionCreating fair and inclusive urban forestry practices that prioritize disadvantaged neighborhoods has been a difficult task for both cities. Acknowledging and addressing past policies and cultural perspectives that have led to marginalization is crucial for building trust with these communities. Moving forward, prioritizing recognitional justice in urban forest planning and management should be a top priority.

Role of Tree Vegetation and Associated Environmental Factors on the Understory Herb-Layer Composition in a Reforested Area: A Study from “Kulon Progo Community Forestry”

We assessed the understory herb-layer species composition in response to tree vegetation and its associated environmental factors in the reforested area of the Kulon Progo Community Forestry, Yogyakarta, Indonesia. The understory herb-layer composition among different stand types, including Pinus (PN), Aleurites-Swietenia (AS), Swietenia-Acacia (SA), Melaleuca-Acacia (MA) and Tectona-Dalbergia (TD), was compared using some comparison analyses. The influence of tree vegetation characteristics and associated environmental factors on the understory herb-layer species was analyzed by employing canonical correspondence analysis (CCA). Our result showed variation in understory herb-layer species composition despite equality in richness and diversity indices. Among all stand types, the MA stand showed fewer shade-tolerant species, and the TD stand exhibited the smallest number of shade-intolerant species. Seedling availability also varied between AS and MA, which contained fewer seedling species. One of the main species in the two stands did not even regenerate. Moreover, all indicator species in MA were shade-intolerant species with invasive characteristics, while those in TD were shade-tolerant and semi-shade-tolerant species. CCA showed that stand types held an important role in the herb-layer species composition, where the number of shade-tolerant and seedling species commonly native to forest were directly proportional to tree canopy coverage, silt proportion in soil texture and concentration of soil organic carbon yet inversely proportional to below-stand utilization. In contrast, the number of shade-intolerant species had positive correlation to below-stand utilization and inversely to other correlated factors. Our study also indicated the possibility of tree vegetation controlling several environmental factors, where the increase in canopy coverage was followed by an increasing proportion of silt in soil texture and concentration of soil organic carbon, as well as a decreasing percentage of below-stand utilization. Accordingly, we recommend tree species enrichment with dense-canopy trees and adaptive management of below-stand utilization for better forest development and tree regeneration. This finding provides important knowledge for evaluation and improvement in the ecological restoration of degraded forests.

The canopy cover Webmap of the United Kingdom’s towns and cities

ABSTRACT Urban trees and other green infrastructure are advocated as a cost-effective sustainable solution to ameliorate the socio-economic and environmental challenges of urbanisation. UK research has only recently started to quantify urban trees. Tree canopy cover percentage (TCC) is a useful indicator of tree presence. Its estimation can be reproducible, simple, fast, and cost-effective; it can also be evaluated through citizen science, improving people’s appreciation for urban trees and widening the data collection resource pool. This research summarises a citizen science assessment of the TCC of the UK’s 5,749 urban wards. Descriptive statistics are presented spanning local authority to country. The area-weighted mean (and standard error) of TCC across urban wards was 17.3 ± 0.1%. Nationally, the TCC were 11.8 ± 0.5%, 15.7 ± 0.5%, 17.5 ± 0.2%, and 18.1 ± 0.5%, for Northern Ireland, Scotland, England, and Wales, respectively. Results show that only 27.6% of urban wards had a TCC higher than 20%, previously suggested as a minimum target for UK towns. The findings highlight substantial geographical variance in TCC equity, as well as a negative correlation between TCC and deprivation. This information will be of value in urban forest strategy and management.

Using citizen science data to investigate annual survival rates of resident birds in relation to noise and light pollution

Exponential increases in anthropogenic noise and light pollution have accompanied growth of the built environment. Noise and light cause negative consequences for birds, such as disrupted navigation during migration, mortality from collisions with windows and other infrastructure, and reduced reproductive success, as well as some positive consequences, such as expanded night niches for behaviors associated with feeding, territoriality, and mating. Relatively less is known about noise and light effects on annual survival of non-migratory birds, so we conducted an exploratory study to examine variation in adult survival rates of seven avian species in relation to noise and light pollution. We used 20 years of band-resight data collected as a part of the Neighborhood Nestwatch Program (NN), a citizen science project run by the Smithsonian Migratory Bird Center, at 242 sites in greater Washington, D.C. USA. We estimated apparent survival and documented species-specific relationships with light and noise. Gray Catbird (Dumetella carolinensis) and House Wren (Thryothorus aedon) survival decreased and American Robin (Turdus migratorius) survival increased with greater amounts of anthropogenic light. Anthropogenic noise had no relationship with apparent survival for any of the seven species. Life-history trade-offs between survival and reproduction may account for differences in species-specific effects of light pollution. Future research should examine the availability of other fine scale environmental conditions, such as tree canopy cover, that might buffer avian exposure to noise and light pollution.

Street trees and Urban Heat Island in Glasgow: Mitigation through the ‘Avenues Programme’

Glasgow, Scotland, is embarking on an ambitious plan to convert all city centre thoroughfares into tree-lined streets (the ‘Avenues Programme’) to make the city centre more people-friendly, attractive, greener, sustainable and economically competitive. While it is well-known that urban green infrastructure (UGI) is a promising strategy to address overheating in urban areas, evidence for the surface temperature, air temperature and thermal comfort effects of street trees is contradictory. In the context of a city-centre-wide ‘Avenues Programme’ in Glasgow, we explore its co-benefits in terms of temperature and thermal comfort. We used a multi-method approach, combining GIS-based spatial analysis with fieldwork, microclimate modelling and statistical analysis to determine the scale of the overheating problem and the likely role of its mitigation based on the ‘Avenues Programme’ case study. We show that the Surface Urban Heat Island (SUHI) differences within the city are of the same magnitude as the urban-rural anomaly and “hot” spots are localized in the city centre area and are clustered in different patterns depending on the severity of background temperatures. Therefore, small, isolated patches of vegetation would not be effective for cooling the clusters of overheated areas. Air temperature showed non-linear relationship with tree canopy cover and the relationship is stronger at medium scale. The ‘Avenues Programme’ as a whole, could eliminate the UHI effect in the city centre, with some tree species completely eliminating the UHI in the city centre. Once complete, the ‘Avenues Programme’ could significantly improve thermal comfort during heatwaves from the current ‘hot’ category to ‘slightly warm’ across the city centre.

Conservation planning in national parks may benefit from site occupancy and detection estimates of native animal species

Protected areas are the best strategy to conserve native biodiversity around the world. In Southeast Asia, most of the pristine tropical forest habitats are limited to terrestrial protected areas such as national parks and wildlife reserves. Endau Rompin National Park (ERNP) is one of undisturbed biodiversity-hotspots in the southern region of Peninsular Malaysia but surrounded by industrial oil palm plantations and threatened by habitat fragmentation. To date, little is known about the distribution and habitat requirement of wildlife, including those conservation priority species in the ERNP. This study aims to investigate the mammal distribution in the ERNP by estimating the probability of occurrence of a species among sampled sites. At 24 camera-trapping sites, we used passive infrared camera traps to detect the forest wildlife. We estimated wildlife occupancy by using single-season occupancy analysis while considering of imperfect detection and relating it to stand- and landscape-level variables. We detected 26 species of native wild animals in the study area including several conservation priority species such as Asian elephant, Asian tapir, and Malayan tiger. The site occupancy of conservation-priority species attests to ERNP's status as an important regional biodiversity hotspot. The detection probabilities of wildlife species were highly sensitive to specific ecological variables at stand- and landscape-level. Our data indicated that tree canopy cover, forest edges, adjacent human settlements, and riparian habitats (e.g., stream and river) are crucial for the persistence of the native wildlife species. Our results suggest that pristine forest habitat such as those typical to the ERNP are critical for wildlife conservation. We suggest that the stand- and landscape-level ecological variables are considered in the conservation planning to protect the forest biodiversity and ecological integrity of the national park and other terrestrial protected areas in the tropics.

Modelling tree canopy cover and evaluating the driving factors based on remotely sensed data and machine learning

Quantifying urban tree cover is important to ensure sustainable urban ecosystem. This study calculates urban percent tree cover (PTC) for Bursa city, Turkey from Sentinel-2 data and evaluates the driving factors of PTC using an Artificial Neural Network-Multi Layer Perception (ANN-MLP) approach. For the PTC calculation, a Regression Tree (RT) analysis was performed using several vegetation indices (NDVI, LAI, fCOVER, MSAVI2, and MCARI) to improve accuracy. Socio-economic, topographic, and biophysical variables were incorporated into the ANN-MLP approach to evaluate the factors that drive urban PTC. A PTC prediction map was generated with an accuracy of 0.95 and a coefficient of determination of 0.87. The ANN-MLP training process yielded a correlation coefficient value of 0.71 and an R-square of 0.82 was achieved between the predicted ANN-MLP and observed tree cover maps. A priority tree cover map was generated considering statistical relationships between the factors and the ANN-MLP prediction map in addition to visual interpretations at the urban scale. Results demonstrate that, unlike other urban forms, PTC has a statistically negative relationship with the gross dwelling density (R2 =0.31). Topographic variables including slope and DEM were positively correlated with PTC with the R2 value of 0.80 and 0.72 respectively. The integration of remote sensing data with vegetation indices and driving factors yielded accurate prediction for identifying and evaluating the variability in the urban PTC.

Topography and canopy cover influence soil organic carbon composition and distribution across a forested hillslope in the discontinuous permafrost zone

AbstractTopography and canopy cover influence ground temperature in warming permafrost landscapes, yet soil temperature heterogeneity introduced by mesotopographic slope positions, microtopographic differences in vegetation cover, and the subsequent impact of contrasting temperature conditions on soil organic carbon (SOC) dynamics are understudied. Buffering of permafrost‐affected soils against warming air temperatures in boreal forests can reflect surface soil characteristics (e.g., thickness of organic material) as well as the degree and type of canopy cover (e.g., open cover vs. closed cover). Both landscape and soil properties interact to determine meso‐ and microscale heterogeneity of ground warming. We sampled a hillslope catena transect in a discontinuous permafrost zone near Fairbanks, Alaska, to test the small‐scale (1 to 3 m) impacts of slope position and cover type on soil organic matter composition. Mineral active layer samples were collected from backslope, low backslope, and footslope positions at depths spanning 19 to 60 cm. We examined soil mineralogical composition, soil moisture, total carbon and nitrogen content, and organic mat thickness in conjunction with an assessment of SOC composition using Fourier‐transform ion cyclotron resonance mass spectrometry (FT‐ICR‐MS). Soils in the footslope position had a higher relative contribution of lignin‐like compounds, whereas backslope soils had more aliphatic and condensed aromatic compounds as determined using FT‐ICR‐MS. The effect of open versus closed tree canopy cover varied with the slope position. On the backslope, we found higher oxidation of molecules under open cover than closed cover, indicating an effect of warmer soil temperature on decomposition. Little to no effect of the canopy was observed in soils at the footslope position, which we attributed, in part, to the strong impact of soil moisture content in SOC dynamics in the water‐gathering footslope position. The thin organic mat under open cover on the backslope position may have contributed to differences in soil temperature and thus SOC oxidation under open and closed canopies. Here, the thinner organic mat did not appear to buffer the underlying soil against warm season air temperatures and thus increased SOC decomposition as indicated by the higher oxidation of SOC molecules and a lower contribution of simple molecules under open cover than the closed canopy sites. Our findings suggest that the role of canopy cover in SOC dynamics varies as a function of landscape position and soil properties, namely, organic mat thickness and soil moisture. Condition‐specific heterogeneity of SOC composition under open and closed canopy cover highlights the protective effect of canopy cover for soils on backslope positions.

Patterns of regional site index across a North American boreal forest gradient

Forest structure—the height, cover, vertical complexity, and spatial patterns of trees—is a key indicator of productivity variation across forested extents. During the 2017 and 2019 growing seasons, NASA’s Arctic-Boreal Vulnerability Experiment collected full-waveform airborne LiDAR using the land, vegetation and imaging sensor, sampling boreal and tundra landscapes across a variety of ecological regions from central Canada westward through Alaska. Here, we compile and archive a geo-referenced gridded suite of these data that include vertical structure estimates and novel horizontal cover estimates of vegetation canopy cover derived from vegetation’s vertical LiDAR profile. We validate these gridded estimates with small footprint airborne LiDAR, and link >36 million of them with stand age estimates from a Landsat time-series of tree-canopy cover that we confirm with plot-level disturbance year data. We quantify the regional magnitude and variability in site index, the age-dependent rates of forest growth, across 15 boreal ecoregions in North America. With this open archive suite of forest structure data linked to stand age, we bound current forest productivity estimates across a boreal structure gradient whose response to key bioclimatic drivers may change with stand age. These results, derived from a reduction of a large archive of airborne LiDAR and a Landsat time series, quantify forest productivity bounds for input into forest and ecosystem growth models, to update forecasts of changes in North America’s boreal forests by improving the regional parametrization of forest growth rates.

Association between urban greenspace, tree canopy cover and intentional deaths: An exploratory geospatial analysis

Greenspaces can provide restorative experiences, offer opportunities for outdoor recreation, and reduce mental fatigue; all of which may improve community health and safety. Yet few studies have examined the neighborhood-level benefits of greenspace in reducing violent deaths. This study explored the association between three distinct greenspace metrics: public greenspace quantity, public greenspace accessibility, neighborhood tree canopy cover, and intentional deaths (i.e., homicides and suicides). Generalized linear models and spatial error models investigated the association between greenspace, tree canopy and intentional deaths in three geographically distinct cities in North Carolina, USA. Results revealed that increased neighborhood greenspace accessibility and tree canopy cover were associated with reduced intentional deaths in all three urban areas. Neighborhood greenspace accessibility was the most protective factor across all study areas. The association between neighborhood greenspace accessibility and intentional deaths was more significant for non-firearm deaths as compared to firearm deaths, indicating that weapon type may be an important consideration for neighborhood greenspace interventions. Compared to predominantly White neighborhoods, predominantly Black neighborhoods had higher rates of homicide in Asheville and Durham and higher rates of suicide in Charlotte. Future policy and research should focus on improving equitable access to existing and future greenspaces, especially in primarily Black neighborhoods.

Seeing the wood for the trees, irregular silviculture supports bat populations in conifer plantations

Conifer plantations are a major land use globally and provide a range of social, economic and environmental benefits, particularly the provision of timber. There is a growing interest in alternative forestry techniques, such as irregular silviculture, to create more sustainable and resilient plantations in response to climate change. Plantations are often considered poor for bats due to limited structural diversity. Irregular forestry increases structural diversity and reduces growing stocks, with potentially positive effects on bats, but this remains poorly understood in conifer plantations. At two estates in south-west Britain, we specifically tested whether bat species richness and activity respond to (1) the surrounding landscape cover types (2) habitat structure within irregular stands and (3) increasing progress along the transformation continuum in three continuous cover forestry stands undergoing transformation including irregular high forest. Stands further progressed along the transformation continuum had lower basal area, higher mean tree diameter, higher levels of fallen deadwood and greater canopy cover of broadleaf trees. A total of 13 species of bat, equivalent to 76% of the UK resident species were recorded. The activity of six species was significantly influenced by the proportion of four land use types (two positive and two negative associations with conifer woodland, one positive and one negative association with broadleaved woodland, two positive associations with improved grassland and two negative associations with arable) in the surrounding landscape at three spatial scales (500 m, 1500 m and 3000 m around each survey plot). Four species showed significant positive associations with habitat structural features including larger mean tree diameter, greater canopy openness, higher vertical structural complexity, higher quantities of standing and fallen deadwood, and higher canopy cover of broadleaved trees. Many of these habitat features were more prevalent in stands further progressed towards irregular high forest. We did not detect any significant differences in bat species richness or activity levels between the three stand stages, except for Plecotus auritus/austriacus which had higher activity in the Stage 3 stand compared to Stage 2, as the limited replication of our study may have precluded detection of any differences. Our study helps inform us on how bats populations respond to novel management of conifer plantations. Further research to determine thresholds for deadwood and broadleaved trees to further support bats in plantations would be beneficial.

Point of (no) return? Vegetation structure and diversity of restored mangroves in Sulawesi, Indonesia, 14–16 years on

Mangrove forests, benefitting millions of people, experience significant degradation. Global recognition of the urgency of halting and reversing this trend have initiated numerous restoration activities. Restoration success is typically evaluated by estimating mangrove survival and area restored, while diversity and structure of vegetation, as proxies for functional forests, are rarely considered. Here we assess mangrove species richness along sea‐landward transects and evaluate restoration outcomes by comparing number of mangrove species, relative species abundance, biomass, diameter, and canopy cover in “Monoculture Reforestation”, “Mixed Species Regeneration” and adjacent “Reference” forest stands, 14 (Tiwoho site) and 16 years (Likupang site) after restoration activities took place. In the “Monoculture Reforestation” plots, mangrove diversity and structure still closely reflected the original restoration actions, with only one and two “new” species having established among the originally densely planted “foundation” species. In contrast, the “Mixed Species Regeneration” plots were more similar to the “Reference” plots in terms of tree diameter and canopy coverage, but species number, abundance and biomass were still lower. The trajectory of the “Mixed Species Regeneration” plots suggests their similarity with the “Reference” stands will increase over time, whereas such “smooth” transition is unlikely to happen in the planted “Monoculture Reforestation” stands, in the foreseeable future. Implementing frequent small‐scale disturbances in restored forest management would increase stand structure and diversity, accelerating the establishment of a more natural, and likely more functional and resilient forest.

Satisfaction with urban trees associates with tree canopy cover and tree visibility around the home

Many world cities want to expand the number of urban trees. How this expansion occurs should consider what people expect from trees based on how they experience and perceive these trees. Therefore, we need a better understanding of how people perceptually respond to urban tree abundance. This research examined whether people’s satisfaction with urban trees and satisfaction with the management of those trees were related to objective measures of greenery such as the Normalized Difference Vegetation Index (NDVI), percent tree canopy cover, and the Viewshed Greenness Visibility Index (VGVI) for trees. We used a demographically and geographically representative survey of 223 residents in Toronto, Canada, and calculated NDVI, canopy cover, and VGVI at three neighbourhood sizes. We analysed the data using generalized linear regression. We found that canopy cover and VGVI had a positive association with satisfaction with urban trees. The associations were comparatively stronger at larger neighbourhood scales than at smaller scales. There were no statistically significant associations with NDVI or satisfaction with the management of urban trees.

Tree canopy enhances Collembola functional richness and diversity across typical habitats of the Gorongosa National Park (Mozambique)

The role of tree canopies in protecting soil functional diversity is essential for ecosystems threatened by the longer lasting periods of drought, which are predicted to increase in the southern afro-tropical region. Nonetheless, biodiversity inventories of soil mesofauna are scarce in afro-tropical ecosystems, even in emblematic and well-studied protected areas, such as the Gorongosa National Park (GNP). Understanding the interrelationships between tree canopies and soil fauna functional diversity can provide insightful information for future adaptive management to protect wildlife and ecosystem services in the GNP, in the context of climate change. Here we assessed collembolan functional type richness and functional diversity in the dry period and during the rainfall across major GNP habitat types: miombo forests, mixed forests, and open savanna/floodplains. Besides the significant positive influence of rainfall, habitat types also influenced functional type’ richness and diversity of collembolan life-forms. Environmental gradients across habitat types, namely the area of tree canopy cover and its indirect effect on soil local conditions (pH and nutrient availability), explained collembolan functional parameters. Calcium concentrations and soil alkalinity significantly enhanced collembolan functional type richness and functional diversity, respectively. Collembola survival across GNP habitats depended on the canopy buffering in the dry sampling period. These results highlight the key role of tree canopies in creating suitable microhabitat conditions supporting soil functional diversity and the sustainability of soil processes and ecosystem services in GNP.

Evaluating MODIS snow products using an extensive wildlife camera network

Snow covers a maximum of 47 million km2 of Earth's northern hemisphere each winter and is an important component of the planet's energy balance, hydrology cycles, and ecosystems. Monitoring regional and global snow cover has increased in urgency in recent years due to warming temperatures and declines in snow cover extent. Optical satellite instruments provide large-scale observations of snow cover, but cloud cover and dense forest canopy can reduce accuracy in mapping snow cover. Remote camera networks deployed for wildlife monitoring operate below cloud cover and in forests, representing a virtually untapped source of snow cover observations to supplement satellite observations. Using images from 1181 wildlife cameras deployed by the Norwegian Institute for Nature Research (NINA), we compared snow cover extracted from camera images to Moderate Resolution Imaging Spectroradiometer (MODIS) snow cover products during winter months of 2018–2020. Ordinal snow classifications (scale = 0–4) from cameras were closely related to normalized difference snow index (NDSI) values from the MODIS Terra Snow Cover Daily L3 Global 500 m (MOD10A1) Collection 6 product (R2 = 0.70). Tree canopy cover, the normalized difference vegetation index (NDVI), and image color mode influenced agreement between camera images and MOD10A1 NDSI values. For MOD10A1F, MOD10A1's corresponding cloud-gap filled product, agreement with cloud-gap filled values decreased from 78.5% to 56.4% in the first three days of cloudy periods and stabilized thereafter. Using our camera data as validation, we derived a threshold to create daily binary maps of snow cover from the MOD10A1 product. The threshold corresponding to snow presence was an NDSI value of 40.50, which closely matched a previously defined global binary threshold of 40 using the MOD10A2 8-day product. These analyses demonstrate the utility of camera trap networks for validation of snow cover products from satellite remote sensing, as well as their potential to identify sources of inaccuracy.

The unexplored effects of artificial selection on urban tree populations.

The unexplored effects of artificial selection on urban tree populations.

Urban green and blue infrastructure effect on the micro-scale thermal environment in a residential neighborhood: Mueller, Austin, TX

ABSTRACT This study examined the role and importance of various green and blue infrastructure elements in improving the deteriorating urban thermal environment from a post-occupancy evaluation perspective of residential neighborhood development. The results showed that the influential variables in this study were the tree canopy coverage ratio (TCR), tree species, yard area, and distance to a waterbody. In addition, a house with a large yard area increases the amount of direct exposure to solar radiation, so the comfort of the outdoor thermal environment was low. Furthermore, the distance to a waterbody parameter did not have a positive impact on the outdoor thermal comfort level because the dominant wind direction within the study area during the day was opposite to the blue infrastructure. Lastly, geographically weighted regression (GWR) analysis was adopted to identify an improvement to compensate for the relatively low explanatory nature of the ordinary least squares (OLS) models due to spatial correlation.

Greenness exposure: beneficial but multidimensional.

Many studies have shown that greenness has beneficial health effects, particularly on psychological and cardiovascular outcomes. In this narrative review, we provide a synthesis of knowledge regarding greenness exposure and respiratory health. The following outcomes were reviewed: respiratory mortality, lung cancer mortality, lung cancer incidence, respiratory hospitalisations, lung function, COPD, and asthma. We identified 174 articles through a literature search in PubMed, of which 42 were eligible for inclusion in this review. The most common marker for greenness exposure was the normalised difference vegetation index (NDVI), which was used in 29 out of 42 papers. Other markers used were tree canopy cover, landcover/land-use, plant diversity, density of tall trees and subjectively perceived greenness. We found beneficial effects of greenness in most studies regarding respiratory mortality, lung cancer incidence, respiratory hospitalisations and lung function. For lung cancer mortality, asthma and COPD, the effects of greenness were less clear cut. While many aspects of greenness are beneficial, some aspects may be harmful, and greenness may have different health effects in different population subgroups. Future studies of greenness and respiratory diseases should focus on asthma and COPD, on effects in different population subgroups and on disentangling the health effects of the various greenness dimensions.

Integrating community science and agency‐collected monitoring data to expand monitoring capacity at large spatial scales

AbstractMonitoring species to better understand their status, ecology, and management needs is a major expense for agencies tasked with biodiversity conservation. Community science data have the potential to improve monitoring for minimal cost, given appropriate analytical frameworks. We describe a framework for integrating data from the eBird community science platform with agency‐collected monitoring data using a multistate occupancy model. Our model accounts for the structural differences across datasets and allows for estimation of both occupancy and breeding probabilities. The framework was applied to Common Loons (Gavia immer) in Washington State. A total of 766 sites had observation effort, of which 713 sites had only eBird effort, 26 sites had only Washington Department of Fish and Wildlife (WDFW) effort, and 27 sites had both. We predicted that the probability of occupancy was only 0.07 (95% Bayesian credible interval, BCI = 0.02–0.51) at the 2324 sites in our sampling frame, though the probability that Common Loons were breeding at occupied sites was 0.95 (95% BCI = 0.71–1.00). We found that probability of occupancy was positively related to waterbody size (probability of a positive effect = 0.88) and negatively related to an index of human influence (probability of a negative effect = 0.94). We found that probability of breeding at occupied sites was positively related to tree canopy cover (0.86), negatively related to elevation (0.99), and negatively related to barren, scrub/shrub, and herbaceous land cover (0.98). We found that state agency biologists were 16 times more likely to detect breeding Common Loons at a site than were eBird users (0.94, 95% BCI = 0.78–0.99 for agency biologists vs. 0.08, 95% BCI = 0.06–0.10 for eBird users). However, the amount of effort expended by eBird users meant that they confirmed Common Loons at 94 sites while agency biologists confirmed them at just 24 sites, although evidence of reproduction was only contributed by agency biologists. Our results provide a better understanding of the distribution of Common Loons in Washington, while further demonstrating that community science data can be a valuable complement to agency‐collected data, if appropriate frameworks are developed to integrate these data sources.

Are nurse plants useful for facilitating the reintroduction of mid- and late successional tree species in tropical montane cloud forests?

Background: In Mexico, where 50 % of the original Tropical montane cloud forest (TMCF) has been lost due to human activities, the restoration of these forests is essential.
 Questions and/or hypotheses: (1) L. styraciflua favors the survival and growth of Q. germana and M. schiedeana species (2) Are there competitive effects between nurses and beneficiary species? and (3) Is the magnitude of these positive/negative interspecific interactions affected by the canopy cover of nurses?
 Studied species: Liquidambar styraciflua L. (pioneer tree), Magnolia schiedeana Schltdl. (mid-successional tree) and Quercus germana Schltdl. & Cham. (late-successional tree).
 Study site and dates: A fallow in Xilitla, state of San Luis Potosí, Mexico, between 2016 and 2018.
 Methods: Seedling of mid- and late-successional species were transplanted 0.3 m and 2 m away from the stems of pioneer tree (protected and unprotected saplings, respectively). Performance of the species were compared after two years and the effects of canopy cover of pioneer trees.
 Results: Pioneer trees facilitated the establishment probabilities of the mid-and late-successional ones. Increasing canopy cover of pioneer trees enhanced the establishment probabilities of both beneficiary species.
 Conclusions: Joint transplanting of pioneer trees with mid- and late-successional tree seedlings in their close vicinity is a strategy to favor the recovery of the ecosystem.