Conservation gaps and priorities of range-restricted birds in the Northern Andes.

The ongoing destruction of habitats in the tropics accelerates the current rate of species extinction. Range-restricted species are exceptionally vulnerable, yet we have insufficient knowledge about their protection. Species' current distributions, range sizes, and protection gaps are crucial to determining conservation priorities. Here, we identified priority range-restricted bird species and their conservation hotspots in the Northern Andes. We employed maps of the Area of Habitat (AOH), that better reflect their current distributions than existing maps. AOH provides unprecedented resolution and maps a species in the detail essential for practical conservation actions. We estimated protection within each species' AOH and for the cumulative distribution of all 335 forest-dependent range-restricted birds across the Northern Andes. For the latter, we also calculated protection across the elevational gradient. We estimated how much additional protection community lands (Indigenous and Afro-Latin American lands) would contribute if they were conservation-focused. AOHs ranged from 8 to 141,000 km2. We identified four conservation priorities based on cumulative species richness: the number of AOHs stacked per unit area. These priorities are high-resolution mapped representations of Endemic Bird Areas for the Tropical Andes that we consider critically important. Protected areas cover only 31% of the cumulative AOH, but community lands could add 19% more protection. Sixty-two per cent of the 335 species have ranges smaller than their published estimates, yet IUCN designates only 23% of these as Threatened. We identified 50 species as top conservation priorities. Most of these concentrate in areas of low protection near community lands and at middle elevations where, on average, only 34% of the land is protected. We highlight the importance of collaborative efforts among stakeholders: governments should support private and community-based conservation practices to protect the region with the most range-restricted birds worldwide.

Protecting and connecting landscapes stabilizes populations of the Endangered savannah elephant.

The influence of protected areas on the growth of African savannah elephant populations is inadequately known. Across southern Africa, elephant numbers grew at 0.16% annually for the past quarter century. Locally, much depends on metapopulation dynamics-the size and connections of individual populations. Population numbers in large, connected, and strictly protected areas typically increased, were less variable from year to year, and suffered less from poaching. Conversely, populations in buffer areas that are less protected but still connected have more variation in growth from year to year. Buffer areas also differed more in their growth rates, likely due to more threats and dispersal opportunities in the face of such dangers. Isolated populations showed consistently high growth due to a lack of emigration. This suggests that "fortress" conservation generally maintains high growth, while anthropogenic-driven source-sink dynamics within connected conservation clusters drive stability in core areas and variability in buffers.

Correction: Batch-produced, GIS-informed range maps for birds based on provenanced, crowd-sourced data inform conservation assessments.

[This corrects the article DOI: 10.1371/journal.pone.0259299.].

The rate of species extinction in declining or fragmented ecological communities.

Loss of habitat can take many forms, ranging from the fragmentation of once-continuous habitat to the slow erosion of populations across continents. Usually, the harm leading to biodiversity loss is not immediately obvious: there is an extinction debt. Most modelling research of extinction debt has focussed on relatively rapid losses of habitat with species loss happening in response afterwards. In this paper, using a niche-orientated community model we compare and contrast two different mechanisms and find contrasting patterns of extinction debt. From small fragments, we typically see the rapid initial loss of many species, followed by a slower loss of species on larger timescales. When we consider slow incremental declines of population sizes, we find initially a slow rate of extinction which subsequently increases exponentially. In such cases, the delayed extinctions may go undetected initially both because the extinctions may be small relative to background randomness and because rate itself is not constant and takes time to reach its maximum.

Region-wide retreats from lower elevations of range-restricted birds across the Northern Andes.

Local studies show upslope shifts in the distribution of tropical birds in response to warming temperatures. Unanswered is whether these upward shifts occur regionally across many species. We considered a nearly 2000-km length of the Northern Andes, where deforestation, temperature, and extreme weather events have increased during the past decades. Range-restricted bird species are particularly vulnerable to such events and occur in exceptionally high numbers in this region. Using abundant crowd-sourced data from the Cornell Lab of Ornithology database, eBird, and the Global Biodiversity Information Facility, we documented distributions of nearly 200 such species. We examined whether species shifted their elevational ranges over time by comparing observed versus expected occurrences below a low elevational threshold and above a high elevational threshold for 2 periods: before and after 2005. We predicted fewer observations at lower elevations (those below the threshold) and more at upper elevations (those above the threshold) after 2005. We also tested for deforestation effects at lower elevations within each species' distribution ranges. We compared relative forest loss with the differences between observed and expected occurrences across the elevational range. Species' retreats from lower elevations were ubiquitous and involved a 23-40% decline in prevalence at the lowest elevations. Increases at higher elevations were not consistent. The retreats occurred across a broad spectrum of species, from predominantly lowland to predominantly highland. Because deforestation showed no relationship with species retreats, we contend that a warming climate is the most parsimonious explanation for such shifts.

Repliegues regionales desde elevaciones más bajas de aves de distribución restringida en los Andes septentrionales Resumen Los estudios locales muestran cambios en la distribución altitudinal de las aves tropicales como respuesta al aumento de la temperatura. No sabemos si estos cambios suceden en muchas especies a nivel regional. Consideramos casi 2000 km de los Andes septentrionales, en donde la deforestación y los eventos climáticos extremos han incrementado en las últimas décadas. Las aves con distribución restringida son particularmente vulnerables a dichos eventos y su presencia es numerosa en esta región. Usamos datos abundantes de origen colectivo tomados de la base de datos del Laboratorio de Ornitología de Cornell, eBird y el Sistema Global de Información sobre Biodiversidad para documentar la distribución de aproximadamente 200 de estas especies. Analizamos si las especies cambiaron su distribución altitudinal con el tiempo al comparar entre la presencia observada y la esperada bajo un umbral de elevación reducida y por encima de un umbral de elevación alta durante dos periodos: antes y después de 2005. Pronosticamos una cantidad menor de observaciones por debajo del umbral y una mayor cantidad por encima del umbral para después de 2005. También analizamos los efectos de la deforestación en elevaciones más bajas dentro de los rangos de distribución de las especies y comparamos la pérdida relativa del bosque con las diferencias entre la presencia observada y la esperada en todo el rango altitudinal. El repliegue de las especies a partir de las elevaciones más bajas fue ubicuo e involucró una declinación del 23-40% de la prevalencia en las elevaciones más bajas. Los incrementos en las elevaciones más altas no fueron uniformes. Los repliegues ocurrieron a lo largo de un espectro amplio de especies, desde las que predominan en las tierras bajas hasta las que predominan en las tierras altas. Ya que la deforestación no se relacionó con el repliegue, sostenemos que un clima más cálido es la explicación más parsimoniosa para estos cambios.

Species coexistence by wide constant size spacing.

We consider the distribution of fruit pigeons of the genera Ptilinopus and Ducula on the island of New Guinea. Of the 21 species, between six and eight coexist inside humid lowland forests. We conducted or analyzed 31 surveys at 16 different sites, resurveying some sites in different years. The species coexisting at any single site in a single year are a highly nonrandom selection of the species to which that site is geographically accessible. Their sizes are both much more widely spread and more uniformly spaced than in random sets of species drawn from the locally available species pool. We also present a detailed case study of a highly mobile species that has been recorded on every ornithologically explored island in the West Papuan island group west of New Guinea. That species' rareness on just three well-surveyed islands within the group cannot be due to an inability to reach them. Instead, its local status decreases from abundant resident to rare vagrant in parallel with increasing weight proximity of the other resident species.

Mapping potential connections between Southern Africa's elephant populations.

Southern Africa spans nearly 7 million km2 and contains approximately 80% of the world's savannah elephants (Loxodonta africana) mostly living in isolated protected areas. Here we ask what are the prospects for improving the connections between these populations? We combine 1.2 million telemetry observations from 254 elephants with spatial data on environmental factors and human land use across eight southern African countries. Telemetry data show what natural features limit elephant movement and what human factors, including fencing, further prevent or restrict dispersal. The resulting intersection of geospatial data and elephant presences provides a map of suitable landscapes that are environmentally appropriate for elephants and where humans allow elephants to occupy. We explore the environmental and anthropogenic constraints in detail using five case studies. Lastly, we review all the major potential connections that may remain to connect a fragmented elephant metapopulation and document connections that are no longer feasible.

The costs and benefits of primary prevention of zoonotic pandemics.

The lives lost and economic costs of viral zoonotic pandemics have steadily increased over the past century. Prominent policymakers have promoted plans that argue the best ways to address future pandemic catastrophes should entail, "detecting and containing emerging zoonotic threats." In other words, we should take actions only after humans get sick. We sharply disagree. Humans have extensive contact with wildlife known to harbor vast numbers of viruses, many of which have not yet spilled into humans. We compute the annualized damages from emerging viral zoonoses. We explore three practical actions to minimize the impact of future pandemics: better surveillance of pathogen spillover and development of global databases of virus genomics and serology, better management of wildlife trade, and substantial reduction of deforestation. We find that these primary pandemic prevention actions cost less than 1/20th the value of lives lost each year to emerging viral zoonoses and have substantial cobenefits.

Batch-produced, GIS-informed range maps for birds based on provenanced, crowd-sourced data inform conservation assessments.

Accurate maps of species ranges are essential to inform conservation, but time-consuming to produce and update. Given the pace of change of knowledge about species distributions and shifts in ranges under climate change and land use, a need exists for timely mapping approaches that enable batch processing employing widely available data. We develop a systematic approach of batch-processing range maps and derived Area of Habitat maps for terrestrial bird species with published ranges below 125,000 km2 in Central and South America. (Area of Habitat is the habitat available to a species within its range.) We combine existing range maps with the rapidly expanding crowd-sourced eBird data of presences and absences from frequently surveyed locations, plus readily accessible, high resolution satellite data on forest cover and elevation to map the Area of Habitat available to each species. Users can interrogate the maps produced to see details of the observations that contributed to the ranges. Previous estimates of Areas of Habitat were constrained within the published ranges and thus were, by definition, smaller-typically about 30%. This reflects how little habitat within suitable elevation ranges exists within the published ranges. Our results show that on average, Areas of Habitat are 12% larger than published ranges, reflecting the often-considerable extent that eBird records expand the known distributions of species. Interestingly, there are substantial differences between threatened and non-threatened species. Some 40% of Critically Endangered, 43% of Endangered, and 55% of Vulnerable species have Areas of Habitat larger than their published ranges, compared with 31% for Near Threatened and Least Concern species. The important finding for conservation is that threatened species are generally more widespread than previously estimated.

Reconnecting nature.

The U.N. has declared 2021-2030 the 'decade of restoration' (https://www.decadeonrestoration.org). This initiative aspires to many actions, but its agenda must include 'reconnecting nature'. Even when natural habitats remain, they often come in fragments too small or isolated to sustain viable populations. Human activities surround habitats with unsuitable areas or constrict animals' movements with artificial barriers, such as roads or fences. The harm this fragmentation causes is evident. Here, we discuss various actions to mitigate its problems, seeking explicit evidence of their efficacy. These actions range from small-scale, controlled experiments to continent-wide programmes to allow species the freedom to roam. Even simple connections, such as highway overpasses or tunnels, usually allow movement such that the genetic and demographic problems that beset small, isolated populations may be diminished. Showing that species move when we give them the chance to do so may be a sufficient measure of success, even if we do not always understand the consequences in detail.

Spatial models of giant pandas under current and future conditions reveal extinction risks.

In addition to habitat loss and fragmentation, demographic processes-the vagaries of births, deaths and sex ratio fluctuations-pose substantial threats to wild giant panda populations. Additionally, climate change and plans for the Giant Panda National Park may influence (in opposing directions) the extinction risk for wild giant pandas. The Fourth National Giant Panda Census showed pandas living in 33 isolated populations. An estimated 259 animals live in 25 of these groups, ~14% of the total population. We used individual-based models to simulate time series of these small populations for 100 years. We analysed the spatial pattern of their risk of extinction under current conditions and multiple climate change models. Furthermore, we consider the impact of the proposed Giant Panda National Park. Results showed that 15 populations face a risk >90%, and for 3 other populations the risk is >50%. Of the 15 most at-risk populations, national parks can protect only 3. Under the Representative Concentration Pathway 8.5 climate change scenario, the 33 populations will probably further divide into 56 populations. Some 41 of them will face a risk >50% and 35 face a risk >90%. Although national parks will probably connect some fragmented habitats, 26 populations will be outside national park planning. Our study gives practical advice for conservation policies and management and has implications for the conservation of other species in the world that live in isolated, fragmented habitats.

What is biodiversity conservation? : This article belongs to Ambio's 50th Anniversary Collection. Theme: Biodiversity Conservation.

Conservation science is a new and evolving discipline, so it seems prudent to explore different approaches. That said, we should examine what we know and, vitally, what works to conserve biodiversity and what does not. Ecosystem processes determine the fate of many species, but many attempts to theorise about ecosystems have led to ever more fanciful descriptions of nature. All conservation is local. It will only succeed if we find ways to accommodate people and nature. That does not mean indigenous knowledge acquired over millennia will be sufficient to our ever more overcrowded planet. Observational and experimental studies of small populations of wild species, however, do provide practical insights into how to manage biodiversity across much larger geographical extents.

The 2020 elephant die-off in Botswana.

The cause of deaths of 350 elephants in 2020 in a relatively small unprotected area of northern Botswana is unknown, and may never be known. Media speculations about it ignore ecological realities. Worse, they make conjectures that can be detrimental to wildlife and sometimes discredit conservation incentives. A broader understanding of the ecological and conservation issues speaks to elephant management across the Kavango-Zambezi Transfrontier Conservation Area that extends across Botswana, Namibia, Angola, Zambia, and Zimbabwe. Our communication addresses these. Malicious poisoning and poaching are unlikely to have played a role. Other species were unaffected, and elephant carcases had their tusks intact. Restriction of freshwater supplies that force elephants to use pans as a water source possibly polluted by blue-green algae blooms is a possible cause, but as yet not supported by evidence. No other species were involved. A contagious disease is the more probable one. Fences and a deep channel of water confine these elephants' dispersal. These factors explain the elephants' relatively high population growth rate despite a spell of increased poaching during 2014-2018. While the deaths represent only ~2% of the area's elephants, the additive effects of poaching and stress induced by people protecting their crops cause alarm. Confinement and relatively high densities probably explain why the die-off occurred only here. It suggests a re-alignment or removal of fences that restrict elephant movements and limits year-round access to freshwater.

How China expanded its protected areas to conserve biodiversity.

How has the global network of protected areas developed - and which decisions have guided this development? Answering these questions may give insight into what might be possible in the next decade. In 2021, China will host the Convention of Biological Diversity's Conference, which will influence the coming decade's agenda. We consider how China expanded its protected areas in the last half-century. Did concerns about biodiversity protection drive those decisions, or were other factors responsible? Like other countries, China has protected remote places with few people that are unusually cold or dry or both. Despite that, species with small geographical ranges that have the highest risk of extinction are better protected than expected. Importantly, while the growth of total area and number of protected areas has slowed for the last decade, increases in protection of forested ecosystems and the species they contain have steadily increased. China's future reserve expansion must consider where to protect biodiversity, not just how much area to protect.

Using metapopulation theory for practical conservation of mangrove endemic birds.

As a landscape becomes increasingly fragmented through habitat loss, the individual patches become smaller and more isolated and thus less likely to sustain a local population. Metapopulation theory is appropriate for analyzing fragmented landscapes because it combines empirical landscape features with species-specific information to produce direct information on population extinction risks. This approach contrasts with descriptions of habitat fragments, which provide only indirect information on risk. Combining a spatially explicit metapopulation model with empirical data on endemic species' ranges and maps of habitat cover, we calculated the metapopulation capacity-a measure of a landscape's ability to sustain a metapopulation. Mangroves provide an ideal model landscape because they are of conservation concern and their patch boundaries are easily delineated. For 2000-20015, we calculated global metapopulation capacity for 99 metapopulations of 32 different bird species endemic to mangroves. Northern Australia and Southeast Asia had the highest richness of mangrove endemic birds. The Caribbean, Pacific coast of Central America, Madagascar, Borneo, and isolated patches in Southeast Asia in Myanmar and Malaysia had the highest metapopulation losses. Regions with the highest loss of habitat area were not necessarily those with the highest loss of metapopulation capacity. Often, it was not a matter of how much, but how the habitat was lost. Our method can be used by managers to evaluate and prioritize a landscape for metapopulation persistence.

Uso de la Teoría de Metapoblaciones para la Conservación Práctica de las Aves Endémicas de Manglares Resumen A medida que un paisaje se fragmenta cada vez más debido a la pérdida de hábitat, los parches se vuelven más pequeños y aislados y, por lo tanto, menos propensos a sostener a una población local. La teoría de metapoblaciones es adecuada para analizar paisajes fragmentados porque combina características empíricas del paisaje con información de cada especie para producir información directa sobre los riesgos de extinción de la población. Este enfoque contrasta con las descripciones de los fragmentos de hábitat que solo proporcionan información directa sobre el riesgo. Mediante la combinación de un modelo metapoblacional espacialmente explícito con datos empíricos de los rangos de distribución de especies endémicas y mapas de la cobertura del hábitat, calculamos la capacidad de la metapoblación - una medida de la capacidad del paisaje para sostener una metapoblación. Los manglares proporcionan un paisaje modelo ideal porque son de interés para la conservación y los límites de los parches son delineados fácilmente. Calculamos la capacidad de la metapoblación global para el período 2000-2015 de 99 metapoblaciones de 32 especies de aves endémicas de manglares. El norte de Australia y el sudeste de Asia tuvieron la mayor riqueza de aves endémicas de manglares. El Caribe, la costa del Pacífico de Centroamérica, Madagascar, Borneo y parches aislados en el sudeste de Asia en Myanmar y Malasia tuvieron las mayores pérdidas de metapoblaciones. Las regiones con mayor pérdida hábitat fueron necesariamente aquellas con mayor pérdida de capacidad de la metapoblación. A menudo no era una cuestión de cuánto, sino cómo se perdió el hábitat. Nuestro método se puede utilizar por manejadores para evaluar y priorizar un paisaje para la persistencia de la metapoblación.

Bird extirpations and community dynamics in an Andean cloud forest over 100 years of land-use change.

Long-term studies to understand biodiversity changes remain scarce-especially so for tropical mountains. We examined changes from 1911 to 2016 in the bird community of the cloud forest of San Antonio, a mountain ridge in the Colombian Andes. We evaluated the effects of past land-use change and assessed species vulnerability to climate disruption. Forest cover decreased from 95% to 50% by 1959, and 33 forest species were extirpated. From 1959 to 1990, forest cover remained stable, and an additional 15 species were lost-a total of 29% of the forest bird community. Thereafter, forest cover increased by 26% and 17 species recolonized the area. The main cause of extirpations was the loss of connections to adjacent forests. Of the 31 (19%) extirpated birds, 25 have ranges peripheral to San Antonio, mostly in the lowlands. Most still occurred regionally, but broken forest connections limited their recolonization. Other causes of extirpation were hunting, wildlife trade, and water diversion. Bird community changes included a shift from predominantly common species to rare species; forest generalists replaced forest specialists that require old growth, and functional groups, such as large-body frugivores and nectarivores, declined disproportionally. All water-dependent birds were extirpated. Of the remaining 122 forest species, 19 are vulnerable to climate disruption, 10 have declined in abundance, and 4 are threatened. Our results show unequivocal species losses and changes in community structure and abundance at the local scale. We found species were extirpated after habitat loss and fragmentation, but forest recovery stopped extirpations and helped species repopulate. Land-use changes increased species vulnerability to climate change, and we suggest reversing landscape transformation may restore biodiversity and improve resistance to future threats.

Extirpaciones de Aves y las Dinámicas Comunitarias en un Bosque Nuboso Andino durante más de Cien Años de Cambios de Uso de Suelo Resumen Los estudios a largo plazo para entender cambios en la biodiversidad todavía son escasos - especialmente en las montañas tropicales. Examinamos los cambios en la comunidad de aves del bosque de San Antonio en los Andes colombianos, desde 1911 hasta 2016. Evaluamos los efectos pasados del cambio en el uso del suelo y analizamos la vulnerabilidad de las especies ante la disrupción climática. La cobertura del bosque disminuyó del 95% al 50% para el año 1959, y 33 especies de bosque fueron extirpadas. Desde 1959 y hasta 1990, la cobertura permaneció estable y se perdieron 15 especies más - un total del 29% de la comunidad de aves de bosque. A partir de ahí la cobertura del bosque incrementó en un 26% y 17 especies recolonizaron el área. La principal causa de las extirpaciones fue la pérdida de conectividad con los bosques adyacentes. De las 31 (19%) especies de aves extirpadas, 25 especies tienen una distribución periférica a San Antonio, principalmente en las tierras bajas. La mayoría de las especies aún tenían presencia regional, pero las conexiones rotas entre los bosques limitaron su recolonización. Otras causas de las extirpaciones fueron la caza, el mercado de fauna y el desvío de cursos de agua. Los cambios en la comunidad de aves incluyeron una transición de especies predominantemente comunes a especies raras; las especies generalistas de bosque reemplazaron a las especies especialistas que requieren bosques maduros y los grupos funcionales, como los grandes frugívoros y nectarívoros, declinaron desproporcionadamente. Todas las aves dependientes del agua fueron extirpadas. De las 122 especies que permanecen en el bosque, 19 son vulnerables a la disrupción climática, diez han disminuido en abundancia y cuatro se encuentran amenazadas. Nuestros resultados muestran una pérdida inequívoca de especies y cambios en la estructura y abundancia de la comunidad de aves a escala local. En general, encontramos que las especies fueron extirpadas después de la pérdida y fragmentación del hábitat, pero la recuperación del bosque detuvo las extirpaciones y ayudó a las especies a recolonizar. Los cambios en el uso de suelo incrementaron la vulnerabilidad de las especies ante el cambio climático, por lo que sugerimos que revertir la transformación del paisaje podría restaurar la biodiversidad y aumentar la resistencia a futuras amenazas.

Measuring resilience is essential if we are to understand it.

"Sustainability", "resilience", and other terms group under the heading of "stability." Their ubiquity speaks to a vital need to characterise changes in complex social and environmental systems. In a bewildering array of terms, practical measurements are essential to permit comparisons and so untangle underlying relationships.