Anthropogenic Cover Research Articles

The relative influence of landscape features on maternity roost and hibernaculum selection in temperate bats

Many animal life-history stages center around residences (nests, roosts, etc.) where the availability of resources within an optimal range can affect fitness. Understanding factors influencing residence selection is fundamental for efficient management or recovery plans. Many bat species use permanent roosts during different periods of the year, and while most conservation plans aim to protect these roosts, the availability of suitable habitat near the roosts (e.g., foraging habitat) is also critical to consider. We evaluated the importance of landscape features at multiple scales surrounding seasonal bat roosts in two regions (north and south) of Québec (Canada), using data from participatory science and government databases. In the human-altered environment of south Québec, bats selected maternity roosts with high anthropogenic cover and water edge density at the 150 m and 2 km scales, respectively. Conversely, roost selection in north Québec, a forested area, could not be explained by any landscape features. In winter, fewer bats used hibernacula located in heavily human-modified landscapes—opposite to the trend observed with maternity roost selection. Our study demonstrates how considering landscape features at the appropriate temporal and spatial scales can promote more efficient conservation for bats.

Estimating the effects of meteorology and land cover on fire growth in Peru using a novel difference equation model

Abstract. Statistical analyses of wildfire growth are rarely undertaken, particularly in South America. In this study, we describe a simple and intuitive difference equation model of wildfire growth that uses a spread parameter to control the radial speed of the modeled fire and an extinguish parameter to control the rate at which the burning perimeter becomes inactive. Using data from the GlobFire project, we estimate these two parameters for 1003 large, multi-day fires in Peru between 2001 and 2020. For four fire-prone ecoregions within Peru, a set of 24 generalized linear models are fit for each parameter that use fire danger indexes and land cover covariates. Akaike weights are used to identify the best-approximating model and quantify model uncertainty. We find that, in most cases, increased spread rates and extinguish rates are positively associated with fire danger indexes. When fire danger indexes are included in the models, the spread component is usually the best choice, but we also find instances when the fire weather index and burning index are selected. We also find that grassland cover is positively associated with spread rates and extinguish rates in tropical forests, and that anthropogenic cover is negatively associated with spread rates in xeric ecoregions. We explore potential applications of this model to wildfire risk assessment and burned area forecasting.

Effects of landscape structure and land use on turtle communities across the eastern United States

Landscape context is integral to population ecology, affecting a range of life history parameters, yet very little is known about how landscape structure influences many taxa. We sampled wetlands at 531 sites across 16 states in the eastern U.S. to examine the influence of landscape heterogeneity and anthropogenic land use on the relative abundance of freshwater turtles, one of the most endangered vertebrate clades in the world. Specifically, we aimed to understand how two components of landscape structure — compositional heterogeneity (wetland diversity) and configurational heterogeneity (wetland aggregation) — influence turtles with varying life history traits. Our results suggest that wetland configuration can modulate the relationship between relative abundance and anthropogenic land use. For example, spotted turtle (Clemmys guttata) was negatively associated with hay/pasture cover when wetlands were less aggregated, but this relationship subsided as aggregation increased. Notably, the way wetland aggregation modulated land use relationships varied across species. These results suggest that some anthropogenic cover types are not strictly positive or negative for certain species, but are instead context-dependent. Relative abundance also generally increased with higher wetland diversity, indicating the potential importance of landscape supplementation for turtles. We report a range of responses to roads that did not strictly correspond with well-established predictions related to body size and terrestrial activity patterns, including positive associations for certain species. Overall, our study supports the use of context-driven approaches to land use-related conservation and management decisions rather than blanket prescriptions, and further emphasizes that effective conservation of freshwater systems requires a landscape-level perspective.

Drivers of primate richness and occurrence in a naturally patchy landscape in the Brazilian Amazon

We assessed the spatial extent at which the species-landscape relationship is strongest (i.e. the scale of effect—SE) on primate occurrence (Alouatta belzebul, Saguinus midas, Saimiri sciureus, and Sapajus apella and Cebus olivaceus, the last two considered together in the analysis) and species richness and evaluated which landscape, patch, and human variables influence primate distribution in a savanna ecosystem in Brazil. We used nested buffers to measure the landscape attributes, and used these data to assess the SE of the species-landscape relationships. We explored the relative contributions of landscape, patch, and human variables to species richness and occurrences by using Generalized Linear Mixed Models and logistic regression. We found that the SE did not differ between primates, but did between two regions with different matrix composition. At the landscape level, occurrence of all species was higher as the distance to the nearest block of continuous forest decreased, but was lower as the amount of water bodies and anthropogenic cover in the matrix increased. The occurrence of S. apella, C. olivaceus and A. belzebul was positively related to forest cover, and all species but A. belzebul had higher occurrence in taller forest. The occurrence of S. apella, C. olivaceus and A. belzebul decreased closer to the city, and S. apella and C. olivaceus presence increased with the number of residents. Richness was negatively related to the number of residents and anthropogenic cover, but positively to forest height. We concluded that conservation planning for primates should follow a “functional landscape” perspective, by maintaining higher forest cover and minimizing the anthropogenic alterations in the matrix.

Defaunation Leads to Functional Loss in a Tropical Biodiversity Hotspot

Defaunation is considered one of the main drivers of modifications in tropical ecosystems, extirpating many large-sized vertebrates, which in turn compromises key ecological functions. Although much attention has been given to predict the effects of species loss on ecological processes, there is a lack of information on the large-scale effects of defaunation. Knowledge gaps such as at which spatial scales biodiversity loss affects ecosystem functioning and ecological functions, and what is the relationship between species loss and preservation of ecological functions, remain poorly understood. Mammals perform important ecological functions, but are widely affected by habitat loss and modification, being considered as priority for conservation worldwide. Thus, determining the impact of land use changes on ecological patterns and process performed or influenced by mammals is of critical importance. Here, we detected erosion in the prevalence of ecological functions performed by mammals mediated by changes in the landscape structure of a tropical biodiversity hotspot in Brazil. By analyzing the loss of different ecological functions (vertebrate and invertebrate predation, seed dispersal, seed depredation, herbivory) in a defaunation gradient, we observed that vulnerable functions (performed by sensitive species) were positively related to patch size and forest cover and negatively related to anthropogenic cover. These relationships were reversed for persistent functions (performed by resilient species). Vulnerable functions were virtually restricted to large forest remnants, while persistent functions were prevalent in human-modified landscapes. Our study adds knowledge on how large-scale defaunation mediated by changes in landscape structure affects ecological functions.

Unraveling the scales of effect of landscape structure on primate species richness and density of titi monkeys (Callicebus nigrifrons)

AbstractIn the Anthropocene, many animal populations are increasingly confined to human‐modified landscapes, in which different spatial variables describing landscape composition and configuration influence species persistence. Forest specialist species are particularly vulnerable to these landscape disturbances. Yet, landscape effects may be undetected if assessed at the wrong spatial scale. Thus, identifying the “scale of effect”, which is the optimal spatial scale for estimating ecological responses to each landscape variable, is needed to understand the impact of landscape structure modification on species. Here, we explored the scale of effect of two compositional (forest cover and anthropogenic cover) and two configurational landscape variables (forest patch density and forest edge density) on two ecological responses: primate species richness and group densities of titi monkeys (Callicebus nigrifrons). We sampled 16 study sites in northeastern São Paulo State, Brazil. For each site, we measured each landscape variable within 10 different‐sized landscapes ranging from 0.2 to 28.3 km2 to identify the scale of effect of each landscape variable. The strength of all the primate‐landscape relationships varied across spatial scales. Although both ecological responses were most strongly associated with forest cover at the largest scale, the scale of effect of the other landscape variables differed between the response variables. These results suggest that each response variable is shaped by landscape patterns and processes operating across different spatial scales. We highlight the importance of separately assessing the scale of effect of each landscape variable on each ecological response to better understand the impact of landscape structure on species persistence.

Modeling of ecosystem services informs spatial planning in lands adjacent to the Sarvelat and Javaherdasht protected area in northern Iran

Dynamic models of ecosystem services supply and scenario analysis of changes in multiple services are being increasingly used to support land use planning and decision making. This approach reduces potential and real conflicts among various stakeholders potentially creating win–win solutions for all. It is particularly applicable in areas where insufficient land for agriculture and settlements is resulting in high rates of conversion of natural forest and grasslands. We quantified and mapped multiple ecosystem services, including habitat provision as a proxy for biodiversity, carbon storage and sequestration, and water balance and supply in the Sarvelat and Javaherdasht region of the globally-significant Hyrcanian (Caspian) forests in northern Iran using the Integrated Valuation of Ecosystem Services and Tradeoffs tool. This region is experiencing a rapidly increasing rate of forest conversion and as a result, the protected area located within the study landscape is threatened by human encroachment. Plausible future landscapes were modeled under three scenarios: (i) business as usual; (ii) protection-based zoning which reflects an expansion of the protected area boundary to prevent land use changes; and (iii) collaborative zoning through redefining the protection boundary simultaneously with an adjustment to meet local stakeholders’ objective of expansion of anthropogenic cover. The results showed that the collaborative zoning scenario would best contribute to effective policy because it presents a more rational spatial configuration of the landscape maintaining the provision of ecosystem services. This scenario may lead to reduced environmental impacts while achieving less conflict between the government and local communities. These results will help to inform and shape natural resource management policies in Iran and is applicable elsewhere in the world.

ALTERAÇÃO NA COBERTURA VEGETAL E USO DA TERRA DA BACIA HIDROGRÁFICA DO ALTO RIO TOCANTINS (GOIÁS): INFLUÊNCIA DAS CARACTERÍSTICAS FÍSICAS E A RELAÇÃO COM AS COMUNIDADES INDÍGENAS

The aim of this study is to analyze the land use and land cover in the upper Tocantins river basin, Goias state, based on the spatial changes in the range of 29 years, the influence of the physical aspects of its dynamic and its impacts on indigenous communities. The methodology was based on GIS techniques and literature. The spatial area was defined from the processing of digital eleva tion models (DEM), in reference to the drainage basin confluent to “Serra da Mesa” hydroelectric plant (HEP), northern state of Goias . Landsat 5 and 8 satelite images were used, which were preprocessed, classified and highlighted. The characterization of the physical environment was carried from the compilation of thematic maps (geological units, geomorphic units and soils) and the MDE. To associate the indigenous community, literature search was performed, searching the literature, publications related to the recent history of Indigenous Territories in the area. The classification resulted in a land cover and land use map with three classes: Cerrado, Anthropogenic cover and Water bodies. Over the past 29 years there was a change in predominant class, from cerrado to anthropogenic cover. This alterations occupy, mainly, areas of Oxisols in flat reliefs, in regional planation surface. In the same period, the scenario of landscapes transformation hit two indigenous communities: the Ava - Canoeiro, with the emergence of HEP, and the Tapuia by land pressure. This spatial configuration directs the conservation of Cerrado remaining (fragments) present in the study area.

Broad and local-scale patterns of exotic earthworm functional groups in forests of National Wildlife Refuges of the Upper Midwest, USA

The National Wildlife Refuge System is the world’s largest network of lands set aside specifically for wildlife conservation. For refuge planners and managers tasked with maintaining ecological integrity and wildlife habitat, many uncertainties exist. In forests in the Upper Midwest, for instance, exotic earthworms are impacting ecosystem structure and function, but their community composition and effects on refuges is unknown. We examined the association of earthworm functional group abundance and community composition within upland forests of refuges with broad scale patterns of anthropogenic land use and local scale differences in forest characteristics. Patterns of anthropogenic land cover, including proportion of the land, mean patch area, and largest patch index, were strongly correlated with the biomass of epi-endogeic earthworms. Earthworm community diversity, however, was inversely related to patterns of dominating anthropogenic land cover, and increased under high ratios of natural to anthropogenic lands in the surrounding ecoregion. Within forests, earthworm community composition could be partially explained by variables representing both dispersal opportunities and habitat suitability. In general, heavily-invaded forests had low conifer dominance, high silt content, high basal area, greater amounts of anthropogenic cover within 500 m, and were closer to roads and farther from agriculture. However, the relationship between local forest characteristics and biomass differed greatly among earthworm functional groups and between refuges dominated by natural lands and those dominated by anthropogenic lands. For refuges with high earthworm loads and well developed earthworm communities, managers may be confounded in restoring historic conditions and may need to look at multiple tools, including artificial regeneration, to mitigate for current earthworm effects. In refuges seemingly in earlier stages of earthworm invasion, future planning and management should be tempered by potential effects observed in those refuges in more anthropogenic landscapes.

What has happened to coastal dunes in the last half century? A multitemporal coastal landscape analysis in Central Italy

The current degradation of the Mediterranean coastal landscape highlights the necessity of, performing long term multitemporal analysis to guide land managers seeking to improve coastal, conservation, planning and management. This work sets out to quantify landscape changes for the last, 50 years in one sector of the Italian coast, with emphasis on natural dune cover types, and to analyze, their spatial configuration in relation to the anthropogenic cover types to investigate the processes, underlying these changes. On the basis of detailed land-cover maps (dated 1954, 1986 and 2006), we, assessed landscape changes by transition matrices. The spatial pattern of natural dune cover types, (Beaches with Pioneer annual Vegetation, Herbaceous Dune Vegetation and Woody Dune Vegetation), for the three dates was described by patch-based (Patch Size and Shape Index) and edge-based metrics, (patch shared boundaries with manmade cover types) and compared using the non-parametric, Kruskal–Wallis median test. Multitemporal analyses provided a description of the coastal changes, occurred in the last half century. Particularly notable are consistent intensification of agricultural and, afforestation activities in the inner sectors of the dunes and a widespread urbanization. The natural, dune cover types, originally distributed in few large and elongated patches, have undergone a, substantial reduction of extent and an alteration in their spatial pattern, being now reduced to many, small and regular patches. A significant rise of contacts between natural dune cover types and, urbanized areas and infrastructures was observed. Such landscape analysis could be useful to develop, management strategies for coastal dune areas.

Modeling scale-dependent landscape pattern, dispersal, and connectivity from the perspective of the organism

Understanding the impacts of habitat fragmentation on dispersal is an important issue in landscape and conservation ecology. Here I examine the effects of fine- to broad-scale patterns in landscape structure on dispersal success of organisms with differing life-history traits. An individual-based model was used to simulate dispersal of amphibian-like species whose movements were driven by land cover and moisture conditions. To systematically control spatial pattern, a landscape model was created by merging simulated land cover maps with synthetic topographic surfaces. Landscapes varied in topographic roughness and spatial contagion in agriculture and urban land cover. Simulations included three different species types that varied in their maximum potential dispersal distances by 1-, 2-, or 4-fold. Two sets of simulations addressed effects of varying aspects of landscape structure on dispersal success. In the first set of simulations, which incorporated variable distances between breeding patches, dispersal success was lowest for all species types when anthropogenic cover was patchily distributed. In the second set, with interpatch distances held constant as landscape composition varied, dispersal success decreased as anthropogenic cover became spatially contagious. Both sets revealed strong main effects of species characteristics, interpatch distances and landscape composition on dispersal success; furthermore, scale-dependent patterns in land cover and moisture gradients had a stronger effect on longer- than shorter-ranging species types. Taken together, these simulations suggest that heuristic conservation strategies could potentially be developed based on important but limited life history information.

Landscape cover type and pattern dynamics in fragmented southern Great Plains grasslands, USA

We documented land cover and landscape pattern changes in an area of northwestern Oklahoma, USA using aerial photography from 1965, 1981, and 1995. This region of the southern Great Plains is fragmented by agricultural activity, and in recent years many remnant native grasslands have experienced extensive invasion by woody juniper (Juniperus virginiana L.). Concurrently, many cropland areas are being planted into perennial forage grasses and converted to intensively managed introduced grasslands as part of the U.S. Conservation Reserve Program (CRP). Our objectives were to document land cover and landscape pattern changes in the region relative to the expansion of juniper and CRP activity. We then examined how local landscape dominance by either anthropogenic or woody vegetation patches affected landscape pattern indices. Land cover changes from 1965 to 1995 included substantial increases in juniper woodlands and mixed woodlands that resulted from juniper encroachment into deciduous woodlands. Introduced grasslands also increased in many areas as a result of CRP implementation. Changes in landscape pattern generally reflected the influx of juniper into many areas. Landscapes dominated by woody vegetation had significantly more patches, smaller patches and patch core areas, more total edge, and higher patch diversity than landscapes dominated by anthropogenic cover types. Results indicate that expanding juniper is exacerbating the fragmentation process initiated by previous human activity, and represents a serious threat to the continued integrity and conservation of remaining southern Great Plains grasslands.

Transitions in forest fragmentation: implications for restoration opportunities at regional scales

Where the potential natural vegetation is continuous forest (e.g., eastern US), a region can be divided into smaller units (e.g., counties, watersheds), and a graph of the proportion of forest in the largest patch versus the proportion in anthropogenic cover can be used as an index of forest fragmentation. If forests are not fragmented beyond that converted to anthropogenic cover, there would be only one patch in the unit and its proportional size would equal 1 minus the percentage of anthropogenic cover. For a set of 130 watersheds in the mid-Atlantic region, there was a transition in forest fragmentation between 15 and 20% anthropogenic cover. The potential for mitigating fragmentation by connecting two or more disjunct forest patches was low when percent anthropogenic cover was low, highest at moderate proportions of anthropogenic cover, and again low as the proportion of anthropogenic cover increased toward 100%. This fragmentation index could be used to prioritize locations for restoration by targeting watersheds where there would be the greatest increase in the size of the largest forest patch.