Riparian forest patches are critical for forest affiliated birds in farmlands of temperate Chile

There is ongoing debate among conservationists regarding the value of small habitat patches to sustain wild populations in farmlands. Our goal was to assess bird abundance in riparian forests differing in terms of size, configuration, landscape conditions and degradation level, to both inform the debate and to identify conservation strategies to maintain diverse agricultural landscapes. We conducted bird point-counts in 91 sites in 2016 across an agricultural valley in Chile. Using models that accounted for imperfect detection, we assessed variation in bird densities in riparian forests with different sizes and configuration, landscapes, and habitat characteristics. We found support in univariates models for our prediction that bird densities varied across riparian forest of various sizes and configuration for 10 of 16 bird species. However, when we added landscape and habitat characteristics to the model, we found that the densities of many of the birds were best explained by forest cover around their local (1 ha) and broader (50 ha) landscape combined with forests characteristics (e.g., invasive tree abundance). For example, Black-throated huet-huet and Chucao Tapaculo were positively associated with forest cover at the broader landscape (50 ha), but showed no response to number of patches, patch-size and Euclidean distance. Our results showed no evidence of negative fragmentation effect per se (i.e., after controlling for habitat area). While agricultural landscapes provide habitat for some species that use small forest patches, conservation strategies focusing on maintaining high level of forest cover and native vegetation are required to secure populations of forest affiliated species.

File: Rojas_et_all_BioConservation_2024_Riparian_forest_patches.pdf

National parks influence habitat use of lowland tapirs in adjacent private lands in the Southern Yungas of Argentina

Protected areas are cornerstones of conservation efforts worldwide. However, protected areas do not act in isolation because they are connected with surrounding, unprotected lands. Few studies have evaluated the effects of protected areas on wildlife populations inhabiting private lands in the surrounding landscapes. The lowland tapir Tapirus terrestris is the largest terrestrial mammal of the Neotropics and is categorized as Vulnerable on the IUCN Red List. It is necessary to understand the influence of landscape characteristics on the tapir’s habitat use to enable effective conservation management for this species. Our objectives were to () determine the potential distribution of the lowland tapir’s habitat in the Southern Yungas of Argentina, and () evaluate the role of protected areas and other covariates on tapir habitat use in adjacent private lands. We used records of lowland tapirs to model the species’ potential distribution and determined habitat use with occupancy modelling. Based on the covariates found to be significant in our models, we constructed predictive maps of probability of habitat use and assessed the area of potential habitat remaining for the species. Probability of habitat use was higher in the vicinity of two national parks and small households than further away from them. We found that in % of the lowland tapir’s potential distribution the probability of habitat use is high (..). These areas are near the three national parks in the study area. The probability of detecting lowland tapirs increased with distance to roads. We conclude that national parks play a key role in the persistence of lowland tapir populations on adjacent private lands.

File: Rivera-et-al-2021_National-Parks-influence-habitat-use-of-lowland-tapirs_Southern-Yungas-of-Argentina.pdf

Identifying medium- and large-sized mammal species sensitive to anthropogenic impacts for monitoring in subtropical montane forests

Medium- and large-sized mammals play important roles in maintaining forest ecosystem functions, and these functions often diminish when mammal species are depleted by human activities. Understanding the sensitivity or tolerance of mammal species to human pressure and detecting species changes through monitoring programs can inform appropriate management decisions. The objective of our study was to identify medium- and large-sized mammal species that can be included in a monitoring programein the Southern Yungas of Argentina. We used occupancy modelling to estimate the probability of habitat use (ψ) of 13 of 25 mammal species detected by 165 camera traps placed in forests across a range of human footprint index (HFI) values. As defined by the HFI, 54% of the study area is wilderness. The probabilities of habitat use of two mammal species were significantly associated with the HFI: the lowland tapir (Tapirus terrestris; ψ = 0.33, range = 0.22–0.50) was inversely associated with HFI values, whereas the grey brocket deer (Mazama gouazoubira; ψ = 0.79, range = 0.67–0.87) was positively associated with the HFI. Monitoring the probability of habitat use of the sensitive species (lowland tapir) could help us to detect changes in areas experiencing anthropogenic impacts before they cause extirpation, whereas the high probability of the habitat use values of the tolerant species (grey brocket deer) might indicate that anthropogenic impacts are strongly influencing habitat, signaling that mitigation strategies might be warranted. The Southern Yungas retains an intact mammal fauna, and we showed that the HFI is useful for monitoring anthropogenic impacts on these mammals. There are still opportunities to develop conservation strategies to minimize threats to mammal species in the region by implementing a monitoring program with the proposed species.

File: Bardavid-et-al_2024_Identifying-mammal-species-sensitive-to-anthropogenic-impact_Environmental-Conservation.pdf

Prioritizing global tall forest toward the 30-by-30 goals

The Global Deal for Nature sets an ambitious goal to protect 30% of Earth’s land and ocean by 2030. The 30×30 initiative is a way to allocate conservation resources and extend protection to conserve vulnerable and under protected ecosystems while reducing carbon emissions to combat climate change. However, most prioritization methods for identifying high-value conservation areas are based on thematic attributes and do not consider vertical habitat structure. Global tall forests represent a rare vertical habitat structure that harbors high species richness in various taxonomic groups and is associated with large amounts of aboveground biomass. Global tall forests should be prioritized when planning global protected areas toward reaching the 30×30 goals. We examined the spatial distribution of global tall forests based on the Global Canopy Height 2020 product. We defined global tall forests as areas with the average canopy height above 3 thresholds (20, 25, and30 m). We quantified the spatial distribution and protection level of global tall forests in high-protection zones, where the 30×30 goals are being met or are within reach, and low-protection zones, where there is a low chance of reaching 30×30 goals. We quantified the protection level by computing the percentage of global tall forest area protected based on the 2017 World Database on Protected Areas. We also determined the global extent and protection level of undisturbed, mature, tall forests based on the 2020 Global Intact Forest Landscapes mask. In most cases, the percentage of protection decreased as forest height reached the top strata. In the low-protection zones,<30% of forests were protected in almost all tall forest strata. In countries such as Brazil, tall forests had a higher per-centage of protection (consistently>30%) compared to forests of lower height, presenting a more effective conservation model than in countries such as the United States, where forest protection was almost uniformly<30% across height strata. Our results show an urgent need to target forest conservation in the greatest height strata, particularly in high-protection areas, where most global tall forests are found. Vegetation vertical structure can inform the decision-making process toward the 30×30 goals because it can be used to identify areas of high conservation value for biodiversity protection which also contribute to carbon sequestration.

File: Conservation-Biology-2023-Huang-Prioritizing-global-tall-forests-toward-the-30-30-goals.pdf

Performance of novel remotely-sensed variables in maps of bird species distributions in Argentina

Mitred Parakeet (Psittacara mitratus) eating the fruit of a Schinus sp. tree
Nothofagus forest in Tierra del Fuego, Argentina.
Nothofagus forest in Tierra del Fuego, Argentina.

Halting biodiversity declines and promoting sustainable ecosystem usage are major conservation goals. To do so, it is necessary to understand the environmental correlates of biodiversity patterns.

Environmental variables used in biodiversity modelling come from a variety of sources and have varying levels of power to explain distributions of different species. Many environmental variables that have been used regularly for many years have shortcomings- they may not cover large areas, may not capture suitable habitat, or may not be able to capture changes in environmental conditions over time or space. Increasingly, novel remotely-sensed environmental data are being developed for modelling biodiversity patterns. Novel remotely sensed products may complement or even offer better results than environmental variables that have been used for many years.

Olah set out to identify sets of complementary variables, from among a set of standard variables and newly created variables, that can improve species distribution modelling. Olah used a combination of land cover, elevation, precipitation, and temperature variables, that are commonly used in species distribution modelling, and a set of novel-remotely sensed products to model distributions of forest affiliated bird species in Argentina.

Yungas forest in Calilegua National Park, Jujuy, Argentina
Yungas forest in Calilegua National Park, Jujuy, Argentina

The set of novel environmental variables were created by SILVIS lab postdoctoral researcher Eduarda Silveira. These products measure spatial and interannual variation in the phenology of land surface temperature and forest vegetation greenness. Olah predicted that areas with more spatial variability in phenology and thermal conditions are more likely to host more species because there are a variety of resources and thermal conditions in close proximity, allowing many species to coexist in a small area. These areas may also buffer against high year-to-year variation in conditions because organisms are more likely to have access to refugia or resources that could allow them to persist. Temporal variation in forest greenness or temperature describes how consistent conditions are between years. High variability means that phenological events are not occurring at a predictable time, while low variability means that events are occurring predictably each year.

In another new product developed by Silveira, ground forest inventory data was combined with radar-based remotely-sensed data, resulting in modelled forest structure wall-to-wall across Argentina. Silveira also developed maps of forest phenoclusters and phenocluster diversity. Phenoclusters classify different forest types in Argentina, based on vegetation phenology, land surface temperature, and precipitation. Olah thinks phenoclusters are a more ecologically relevant way to characterize habitat important to bird species than typical land cover maps. Phenoclusters capture functional rather than only compositional or structural characteristics. By comparing how well these novel remotely-sensed products and traditionally used variables perform in species distribution modelling Olah assessed their usefulness for biodiversity mapping.

Polylepis forest in an Andean Mountain valley, Jujuy, Argentina.
Polylepis forest in an Andean Mountain valley, Jujuy, Argentina.

Olah developed species distribution models for 152 forest bird species. She found that among three sets of models she constructed, those containing novel, traditional, or a mixed set of variables, performance was similar. However, models constructed from the mixed set of variables performed slightly better than models containing only one or the other set of data. The variables that were included in the greatest number of individual species’ distribution models included precipitation seasonality, precipitation of the driest quarter, as well as spatial heterogeneity in winter land surface temperature, which is a novel variable. Her results highlight how variables derived from different sources can offer complementary information for biodiversity modelling. Her models contribute to forest harvest planning in Argentina.

Closing the research-implementation gap: Integrating species and human footprint data into Argentina’s forest planning

Closing the research-implementation gap is key for advancing biodiversity conservation. One approach is to generate ecologically relevant spatial datasets that integrate easily with existing management plans. Our goal was to identify priority forest conservation areas in Argentina by combining species distributions, human footprint data, and existing forest zoning. We: (i) mapped potential habitat distributions of 70 plant and animal species associated with forests, and of recognized social and ecological importance, (ii) combined the species distributions with human footprint data to identify priority conservation areas, and (iii) evaluated the juxtaposition of our priority conservation areas with current forest management zones. We found that priority conservation areas (i.e., high number of species and low human footprint) are poorly protected by the current zoning scheme. While the Andean-Patagonian region had a substantial portion (57 %) of priority conservation areas in high protection zones, in four other forest regions we evaluated, only 16–37 % of priority areas had high protection levels. Of great concern are the Chaco and Espinal regions, where 36 % and 39 %, respectively, of priority conservation areas are in low protection zones, where conversion to other uses (row crops, livestock) is allowed. Our results provide new spatial information to managers and conservationists highlighting where current forest zoning performs well, and where it may warrant re-evaluation. Overall, our study highlights the value of integrating species distributions and human footprint maps into existing land use plans to guide conservation efforts in data-poor countries, and is an example of a strategy for closing the research-implementation gap.

File: Martinuzzi-et-al-2023_Closing-research-implementation-gap.pdf

Distribution and habitat use of the endemic Yungas Guan Penelope bridgesi in the Southern Yungas of Argentina

Identifying the factors that determine the spatial distribution and habitat use of species of conservation importance is essential to developing effective conservation and management strategies. As seed dispersers, guans play a key role in the regeneration of forests in South America and are threatened mainly by habitat loss and hunting pressure. The Yungas Guan Penelope bridgesi, an endemic species restricted to the Southern Yungas of Argentina and Bolivia, has been recently recognized as a separate species. To determine the conservation status of Yungas Guan, information on its distribution and habitat use is urgently needed. The objectives of our work were to 1) determine the potential distribution of the Yungas Guan in the Southern Yungas of Argentina and 2) assess the influence of environmental and anthropogenic covariables on habitat use of the species. We used records of Yungas Guan to model the potential distribution of the species with MaxEnt software and developed occupancy models to determine habitat use and influential elements of the landscape (puestos, urban areas, roads, rivers, and elevation). We obtained data on the presence of Yungas Guan with camera traps, with an effort of 6,990 camera trap-days. The total potential distribution of the species was 21,256 km2.We found that the habitat use by Yungas Guan increased with proximity to rivers and streams. The probability of habitat use was 0.27, with a range of 0.02–0.42.Of the total potential distribution area, 15,781 km2 (81%) had a probability of habitat use greater than 0.2. This study is the first in determining the potential distribution of Yungas Guan in the Southern Yungas of Salta and Jujuy provinces in Argentina and highlights the importance of conducting analyses with occupancy models to assess the influence of environmental and anthropogenic variables and threats to cracid species.

File: Tejerina-et-al-2022-BCI.pdf

Arctic waterfowl migration through Eurasian steppe: how to catch short-term environmental conditions and identify key migratory habitats using satellite images

Long-distance migrations are an important part of the life cycle for most Arctic waterfowl. The birds spend several months each year between their breeding and wintering places, with most of this time staying at their stopover sites to rest and feed. Habitat quality at the stopovers determine subsequent survival during migrations and reproductive success. Two questions present themselves: where are the key waterfowl habitats along their migratory routes, and what landscape features make these places vitally important? Understanding this is crucial for bird protection and population management.

Fig. 1 Bewick’s Swan
Fig. 1 Bewick’s Swan

Satellite images are used widely for landscape research; however, their application to bird migration studies is challenging. First, environmental conditions within a large area are not the same during migration period, so there is no single time window suitable to select satellite images for the entire area. Second, favorable conditions at each stopover site are short-term, as birds spend only a few weeks at each site. The needed satellite images may be unavailable for those exact periods due to weather conditions (clouds etc.), making it difficult to obtain sufficient data for a single migratory season. Third, environmental conditions and migration time could vary by several weeks depending on weather of a given year, which, in turn, impedes combining images from different years.

Natalia studied how to use satellite images for delineating key migratory habitats using the example of spring migration of Bewick’s Swan in Eurasian steppe (fig. 1). To overcome the limitation related to satellite image availability, Natalia used snow melt as a synchronizing point. In practice, specific dates on which the swans appear at one or another area do not really matter because the birds will move farther north as soon as ice-free water and food become available there. In other words, they arrive soon after snow melt and stay a couple of weeks until more northern areas become snow-free.

Natalia used daily MODIS data to identify where snow melted each year in different parts of the swan’s migratory flyways and then filtered Landsat images using that information. This allowed her to combine Landsat images for all migration areas from different years at the same phenological phase. This approach made it possible to produce accurate and detailed landscape maps demonstrating what environmental conditions prevailed at stopovers at exactly the time when the swans were present. With these maps species distribution modeling can delineate key swan’s habitats.

Fig.2 Key habitats during summer
Fig.2 Key habitats during summer

The maps have revealed the critical landscape feature important to the birds: numerous local depressions scattered across croplands (fig. 2). In summer these appear as a part of the agricultural landscape (only the smallest, lowermost places may not be ploughed and get overgrown with wildflowers) and are hardly detectable (fig. 3, e) on satellite images. In spring, however, they accumulate melted water to become shallow temporary water bodies (fig. 3, a-c). These flooded depressions provide migratory birds with food and refuge so that the waterfowl do not need to move between roosting and feeding sites. They are also available 10-15 days before ice-out on lakes, allowing birds to migrate and potentially reach breeding grounds earlier.

Fig.3 Changes in open water in the steppe during spring. RGB: SWIR 1, NIR, Red bands. Red circle –flooded fields, yellow square -permanent lake. Bright blue color indicates snow/ice, black color indicates open water.
Fig.3 Changes in open water in the steppe during spring. RGB: SWIR 1, NIR, Red bands.
Red circle –flooded fields, yellow square -permanent lake.
Bright blue color indicates snow/ice, black color indicates open water.

More generally, Natalia’s research provides a useful approach to understanding the key short-term conditions that birds rely on during migrations. Natalia’s results have important implications for conservation efforts, such as the creation of protected areas and free hunting zones and adjusting land management in agricultural lands.

Comparing Approaches to Identify Protected Areas for Wildlife across the U.S.

By schlorian 13 May 2019

Species and populations are declining rapidly, with over 3 billion birds lost in the past 50 years. Astoundingly, the US is on track to lose 50% of its remaining individual birds in 50 more years without intervention ( Birds, unfortunately, are not alone, as 40% of all species are projected to face extinction by the end of this century. Despite these alarming numbers, conservation spending in the US has remained relatively stable over the past years – roughly $6-7 billion with few exceptions. Therefore, one of the most challenging questions for scientists is where will conservation action – and protected areas in particular – do the most to protect species of conservation concern.

Kathleen Carroll’s current work in the SILVIS Lab compares various biodiversity metrics, each with unique assumptions, to my previous maps of threatened/endangered and decreasing species (see my previous webstory for more on that project). I can use these comparisons to evaluate how well these additional metrics, which are usually treated as direct surrogates for biodiversity, capture the conservation patterns necessary to protect threatened or endangered species. I also will evaluate which, if any, combinations of these metrics work best to inform conservation planning on regional and national scales. To do this, I will model all metrics for the US and then compare them directly to my threatened/endangered species data. I will do so using Marxan, a conservation planning problem support tool, to create nationwide maps that identify conservation priority areas. These maps, one for each metric, will include a certainty estimate based on pixel importance across data layers and identify gaps in protected areas. By comparing different metrics, we will be provided maps of high-certainty high-priority areas where land managers and agencies can focus on endangered species conservatio through designation of new protected areas.


How has half a century of land cover changes altered habitats of ungulates in the biologically diverse Caucasus?

Landscapes are undergoing continuous transformation, with both natural and human factors causing the destruction of some habitats and the formation of others. While wildlife can adapt to natural changes, the current scale of human-made landscape alterations is much greater than nature’s ability to adapt. Some species can thrive in human-made landscapes, but others are at risk of extinction due to habitat loss.

Azerbaijan, a country in the Caucasus region with rich biodiversity and a long history of human-driven land cover changes. For conservation and sustainable management there, it is critical to understand the impacts of landscape changes on wildlife habitats. The changes in the Caucasus eco-region have accelerated in the 20th century due to population growth and Soviet nature-transformation efforts. A new study by Afag Rizayeva aims to understand the impact of these changes on the habitats of eight ungulate species, including common animals like wild boar and roe deer, as well as a rare species of gazelle. With landscapes constantly changing due to natural and human causes, it is increasingly important to understand how these changes are affecting wildlife populations.

East Caucasian tur – Capra cylindricornis by Azerchin Muradov

Afag has developed the Caucasus land cover maps for the 1960s using former spy satellite images (Corona) and has analyzed the long-term changes in these landscapes using recent land cover maps derived from Landsat images. Her research begins by using the presence data of eight ungulate species, conducting species distribution modeling to evaluate their current ranges and the landscape features that are most important to each species.

Red deer – Cervus elaphus by Azerchin Muradov

Next, Afag will analyze the changes in land cover within each species’ range, determining stable areas, habitat gains and losses, and assessing the positive or negative effects of these changes on the species’ habitats. This will enable her to determine if the species can continue to use the same areas despite human activities, or if they require urgent land management solutions to protect them. The results of Afag’s study will help guide wildlife conservation planning and will be used by local NGOs and government agencies. As human impact on nature is a global issue, the methodological approach she develops in her research will have applications in other regions facing similar issues.

Chamois – Rupicapra rupicapra
Chamois – Rupicapra rupicapra by Azerchin Muradov

In conclusion, understanding the impact of long-term land cover changes on wildlife habitats is crucial for conservation and sustainable management. The research being conducted by Afag Rizayeva will provide valuable insights into this issue and help guide efforts to protect the wild species in Azerbaijan and beyond. Stay tuned!