Comparing species and measures of landscape structure as indicators of conservation importance

Promoting Bird Functional Diversity on Landscapes with a Matrix of Planted Eucalyptus spp. in the Atlantic Forest

Promoting the diversity of biological communities in areas of agricultural production is a very current debate since protected areas may not be sufficient to ensure biodiversity conservation. Among the biological communities affected by the production areas are birds, which show rapid responses to changes in the landscape. Here we seek to understand how landscape planning, concerning its composition and configuration, in areas with a matrix of planted Eucalyptus spp. forests influences the functional diversity of bird assemblages in the Atlantic Forest. Our results show that the spatial distribution design of planted forests in terms of age, land cover and clone types have effects on bird diversity with regard to functional divergence, functional evenness and species richness. These results reinforce the importance of good management for the maintenance of bird diversity. We found that bird functional diversity in planted forest matrices increased with the proximity index, proportion of native vegetation and age importance value, and is negatively influenced by edge density and proportion of forest plantation. For bird conservation, it is thus better to associate Eucalyptus spp. with other cover types in the landscape. These results corroborate that, to increase bird functional diversity, it is possible to associate conservation and production in the same landscape. Mosaic landscapes have great potential to contribute to the conservation of bird biodiversity outside protected areas. However, decisions regarding the management of planted forests and planning of improved areas intended for conservation seem to be decisive to ensure the maintenance of bird biodiversity.

The importance of patch shape at threshold occupancy: functional patch size within total habitat amount

The habitat amount hypothesis (HAH) stresses the importance of total patch amount over the size of individual patches in determining species richness within a local landscape. However, the absence of some species from patches too small to contain a territory would be inconsistent with the HAH. Using the association of territory size with body size and the circle as optimal territory shape, we tested several HAH predictions of threshold patch occupancy and richness of 19 guilds of primarily insectivorous breeding birds. We characterized 16 guild-associated patch types at high spatial resolution and assigned one type to each guild. We measured functional patch size as the largest circle that fit within each patch type occurring in a local landscape. Functional patch size was the sole or primary predictor in regression models of species richness for 15 of the 19 guilds. Total patch amount was the sole or primary variable in only 2 models. Quantifying patch size at high resolution also demonstrated that breeding birds should be absent from patches that are too small to contain a territory and larger species should occur only in larger patches. Functional patch size is a readily interpretable metric that helps explain the habitat basis for differences in species composition and richness between areas. It provides a tool to assess the combined effects of patch size, shape and perforation on threshold habitat availability, and with total patch amount can inform design and/or evaluation of conservation, restoration or enhancement options for focal taxa or biodiversity in general.

The selection of indicator species of birds and mammals for the monitoring of restoration areas in a highly fragmented forest landscape

Indicator species are frequently used to monitor restoration areas. However, species of conservation concern are usually absent in highly fragmented landscapes, making the selection of indicator species a challenging task. Here, we select indicator species of birds and mammals to be used for the evaluation of restoration sites in a highly fragmented landscape, the Capivara-Taquaruçu Dams region located in north Paraná, Brazil. By using the Index of Biotic Integrity (IBI), we show that the Capivara-Taquaruçu Dams landscape has low IBI values and bird richness when compared with two other landscapes in the north of Paraná. Therefore, we used the Individual Indicate Value to identify birds and mammals associated with forest fragments in the Capivara-Taquaruçu Dams landscape. Six bird and four mammal species were selected as indicators of forest fragments, none of which were of conservation concern. However, monitoring of these species could help evaluate the recovery of restoration sites in the Capivara-Taquaruçu Dams region. Lastly, several species of birds and mammals were frequently recorded in the restoration sites, including vulnerable species such as the lowland tapir (Tapirus terrestris). This is indicative that restoration sites can be important habitats in highly fragmented landscapes despite the loss of biodiversity.

Assessing ecosystem condition at the national level in Hungary - indicators, approaches, challenges

The availability of robust and reliable spatial information on ecosystem condition is of increasing importance in informing conservation policy. Recent policy requirements have sparked a renewed interest in conceptual questions related to ecosystem condition and practical aspects like indicator selection, resulting in the emergence of conceptual frameworks, such as the System of Environmental-Economic Accounting - Ecosystem Accounting (SEEA-EA) and its Ecosystem Condition Typology (ECT). However, while such frameworks are essential to ensure that condition assessments are comprehensive and comparable, large-scale practical implementation often poses challenges that need to be tackled within stringent time and cost frames.

We present methods and experiences of the national-level mapping and assessment of ecosystem condition in Hungary. The assessments covered the whole country, including all major ecosystem types present. The methodology constitutes four approaches of quantifying and mapping condition, based on different interpretations of naturalness and hemeroby, complemented by two more using properties that ‘overarch’ ecosystem types, such as soil and landscape attributes. In order to highlight their strengths and drawbacks, as well as to help reconcile aspects of conceptual relevance with practical limitations, we retrospectively evaluated the six mapping approaches (and the resulting indicators) against the indicator selection criteria suggested in the SEEA-EA. The results show that the various approaches have different strengths and weaknesses and, thus, their joint application has a higher potential to address the specific challenges related to large-scale ecosystem condition mapping.

Small Landscape Elements Double Connectivity in Highly Fragmented Areas of the Brazilian Atlantic Forest

The Atlantic Forest in Brazil is a biodiversity hotspot, yet its diverse ecosystems and species are becoming increasingly threatened by habitat loss and extreme habitat fragmentation. Most habitat patches of Atlantic Forest are dispersed across agricultural landscapes (e.g., grazing and cropping) in relatively small and isolated fragments (80% < 50 ha). Forest fragments < 1 ha, scattered trees in pastures, tree lines on trenches and fences, and remnant riparian forest, collectively called here Small Landscape Elements (SLEs), are very common in this context. While these SLEs make up much of the Atlantic Forests footprint, very little is known about their role or impact on the persistence and conservation of species. In this study, we investigate the role of SLEs on landscape configuration, particularly their contribution toward landscape connectivity of individual species and the genetic flow of species between larger forest fragments. We randomly selected 20 buffers of 707 hectares within a 411,670 hectare area of the Atlantic Forest that was completely covered by forest in the past located in the south of Minas Gerais State, Brazil. The forest cover randomly varied between these buffers. We used graph theory to measure landscape connectivity as the probability of connectivity for different disperser movement types between landscape knots (habitat patches). We used three estimated dispersal distances in the models: pollen disperser insect (50 m), low-mobility seed disperser bird (100 m) and high-mobility seed disperser bird (760 m). The SLEs together increased the probability of connection by roughly 50%, for all model dispersers, if compared to a theoretical baseline landscape containing no SLEs. Of all SLEs, riparian forests contribute the most toward enhancing landscape connectivity. In these highly fragmented landscapes, such as the Atlantic Forest (>70%), the position of SLEs within the landscapes was more important than their respective areas for connectivity. Although the landscapes were deeply fragmented, we showed that the presence of SLEs can increase connectivity and reduce further biodiversity loss in the Atlantic Forest.

Trait-based indicators of bird species sensitivity to habitat loss are effective within but not across data sets

Species' traits have been widely championed as the key to predicting which species are most threatened by habitat loss, yet previous work has failed to detect trends that are consistent enough to guide large-scale conservation and management. Here we explore whether traits and environmental variables predict species sensitivity to habitat loss across two data sets generated by independent avifaunal studies in the Atlantic Forest of Brazil, both of which detected a similar assemblage of species, and similar species-specific responses to habitat change, across an overlapping sample of sites. Specifically, we tested whether 25 distributional, climatic, ecological, behavioral, and morphological variables predict sensitivity to habitat loss among 196 bird species, both within and across studies, and when data were analysed as occurrence or abundance. We found that four to nine variables showed high explanatory power within a single study or data set, but none performed as strong predictors across all data sets. Our results demonstrate that the use of species traits to predict sensitivity to anthropogenic habitat loss can produce predictions that are species- and site-specific and not scalable to whole regions or biomes, and thus should be used with caution.

Indicator-Driven Conservation Planning Across Terrestrial, Freshwater Aquatic, and Marine Ecosystems of the South Atlantic, USA

Systematic conservation planning, a widely used approach to identify priority lands and waters, uses efficient, defensible, and transparent methods aimed at conserving biodiversity and ecological systems. Limited financial resources and competing land uses can be major impediments to conservation; therefore, participation of diverse stakeholders in the planning process is advantageous to help address broad-scale threats and challenges of the 21st century. Although a broad extent is needed to identify core areas and corridors for fish and wildlife populations, a fine-scale resolution is needed to manage for multiple, interconnected ecosystems. Here, we developed a conservation plan using a systematic approach to promote landscape-level conservation within the extent of the South Atlantic Landscape Conservation Cooperative. Our objective was to identify the highest-ranked 30% of lands and waters within the South Atlantic deemed necessary to conserve ecological and cultural integrity for the 10 primary ecosystems of the southeastern United States. These environments varied from terrestrial, freshwater aquatic, and marine. The planning process was driven by indicators of ecosystem integrity at a 4-ha resolution. We used the program Zonation and 28 indicators to optimize the identification of lands and waters to meet the stated objective. A novel part of our study was the prioritization of multiple ecosystems, and we discuss the advantages and disadvantages of this approach. The evaluation of indicator representation within prioritizations was a useful method to show where improvements could be made; some indicators dictated hotspots, some had a limited extent and were well represented, and others had a limited effect. Overall, we demonstrate that a broad-scale (408,276 km2 of terrestrial and 411,239 km2 of marine environments) conservation plan can be realized at a fine-scale resolution, which will allow implementation of the regional plan at a local level relevant to decision making.

Atlantic forest bird communities provide different but not fewer functions after habitat loss

Habitat loss often reduces the number of species as well as functional diversity. Dramatic effects to species composition have also been shown, but changes to functional composition have so far been poorly documented, partly owing to a lack of appropriate indices. We here develop three new community indices (i.e. functional integrity, community integrity of ecological groups and community specialization) to investigate how habitat loss affects the diversity and composition of functional traits and species. We used data from more than 5000 individuals of 137 bird species captured in 57 sites in the Brazilian Atlantic Forest, a highly endangered biodiversity hotspot.Results indicate that habitat loss leads to a decrease in functional integrity while measures of functional diversity remain unchanged or are even positively affected. Changes to functional integrity were caused by (i) a decrease in the provisioning of some functions, and an increase in others; (ii) strong within-guild species turnover; and (iii) a replacement of specialists by generalists. Hence, communities from more deforested sites seem to provide different but not fewer functions. We show the importance of investigating changes to both diversity and composition of functional traits and species, as the effects of habitat loss on ecosystem functioning may be more complex than previously thought. Crucially, when only functional diversity is assessed, important changes to ecological functions may remain undetected and negative effects of habitat loss underestimated, thereby imperiling the application of effective conservation actions.

Assessing the utility of statistical adjustments for imperfect detection in tropical conservation science

In recent years, there has been a fast development of models that adjust for imperfect detection. These models have revolutionized the analysis of field data, and their use has repeatedly demonstrated the importance of sampling design and data quality. There are, however, several practical limitations associated with the use of detectability models which restrict their relevance to tropical conservation science.

We outline the main advantages of detectability models, before examining their limitations associated with their applicability to the analysis of tropical communities, rare species and large‐scale data sets. Finally, we discuss whether detection probability needs to be controlled before and/or after data collection.

Models that adjust for imperfect detection allow ecologists to assess data quality by estimating uncertainty and to obtain adjusted ecological estimates of populations and communities. Importantly, these models have allowed informed decisions to be made about the conservation and management of target species.

Data requirements for obtaining unadjusted estimates are substantially lower than for detectability‐adjusted estimates, which require relatively high detection/recapture probabilities and a number of repeated surveys at each location. These requirements can be difficult to meet in large‐scale environmental studies where high levels of spatial replication are needed, or in the tropics where communities are composed of many naturally rare species. However, while imperfect detection can only be adjusted statistically, covariates of detection probability can also be controlled through study design. Using three study cases where we controlled for covariates of detection probability through sampling design, we show that the variation in unadjusted ecological estimates from nearly 100 species was qualitatively the same as that obtained from adjusted estimates. Finally, we discuss that the decision as to whether one should control for covariates of detection probability through study design or statistical analyses should be dependent on study objectives.

Synthesis and applications. Models that adjust for imperfect detection are an important part of an ecologist's toolkit, but they should not be uniformly adopted in all studies. Ecologists should never let the constraints of models dictate which questions should be pursued or how the data should be analysed, and detectability models are no exception. We argue for pluralism in scientific methods, particularly where cost‐effective applied ecological science is needed to inform conservation policy at a range of different scales and in many different systems.

Models that adjust for imperfect detection are an important part of an ecologist's toolkit, but they should not be uniformly adopted in all studies. Ecologists should never let the constraints of models dictate which questions should be pursued or how the data should be analysed, and detectability models are no exception. We argue for pluralism in scientific methods, particularly where cost‐effective applied ecological science is needed to inform conservation policy at a range of different scales and in many different systems.

Unraveling the drivers of community dissimilarity and species extinction in fragmented landscapes

Communities in fragmented landscapes are often assumed to be structured by species extinction due to habitat loss, which has led to extensive use of the species-area relationship (SAR) in fragmentation studies. However, the use of the SAR presupposes that habitat loss leads species to extinction but does not allow for extinction to be offset by colonization of disturbed-habitat specialists. Moreover, the use of SAR assumes that species richness is a good proxy of community changes in fragmented landscapes. Here, we assessed how communities dwelling in fragmented landscapes are influenced by habitat loss at multiple scales; then we estimated the ability of models ruled by SAR and by species turnover in successfully predicting changes in community composition, and asked whether species richness is indeed an informative community metric. To address these issues, we used a data set consisting of 140 bird species sampled in 65 patches, from six landscapes with different proportions of forest cover in the Atlantic Forest of Brazil. We compared empirical patterns against simulations of over 8 million communities structured by different magnitudes of the power-law SAR and with species-specific rules to assign species to sites. Empirical results showed that, while bird community composition was strongly influenced by habitat loss at the patch and landscape scale, species richness remained largely unaffected. Modeling results revealed that the compositional changes observed in the Atlantic Forest bird metacommunity were only matched by models with either unrealistic magnitudes of the SAR or by models ruled by species turnover, akin to what would be observed along natural gradients. We show that, in the presence of such compositional turnover, species richness is poorly correlated with species extinction, and z values of the SAR strongly underestimate the effects of habitat loss. We suggest that the observed compositional changes are driven by each species reaching its individual extinction threshold: either a threshold of forest cover for species that disappear with habitat loss, or of matrix cover for species that benefit from habitat loss.