Limited and biased global conservation funding means most threatened species remain unsupported

Significance

An analysis of species-based conservation projects over a 25-y period reveals larger and deeper taxonomic biases in funding than previously described, impeding effective biodiversity conservation. Conservation efforts are largely concentrated on a narrow subset of species, some nonthreatened, while most species in urgent need of protection are largely ignored. Both governments and nongovernmental stakeholders urgently need new approaches to help tackle the biodiversity crisis, including realigning funding priorities to ensure representative funding across taxa toward vulnerable and currently neglected species.

Abstract

The conservation of biodiversity represents a global challenge as the world experiences its sixth mass extinction. Understanding how conservation efforts are allocated is paramount to effectively protect threatened species. We analyzed ~14,600 conservation projects over a 25-y period, revealing substantial taxonomic biases in funding. When matched with formal assessments of species’ threat status, several highly threatened groups such as amphibians receive little and ever-decreasing support. Within particular groups (e.g., Mammalia, Reptilia), funding is directed to a very narrow selection of taxa, leaving the majority of their threatened species with limited or no support. More attention is urgently needed to assess the extinction risks of neglected taxa, especially smaller species. Paradoxically, while approximately 6% of species identified as threatened were supported by conservation funds, 29% of the funding was allocated to species of “least concern”. A more holistic distribution of conservation funding is, therefore, urgently needed if we are to protect biodiversity efficiently. We suggest avenues and mechanisms for a more balanced coverage of threatened species within conservation programs and highlight some of the benefits that could be derived from such an approach.

There is little debate that we have entered another global mass extinction event (1–2) and that the protection of biodiversity should be a global priority (3). This crisis, in part, is being addressed by financial support from governmental programs and international nongovernmental organizations (I-NGOs). However, such funding needs to be allocated using objective criteria to avoid taxonomic biases toward certain groups (e.g., large and “charismatic” vertebrates, 4–12). The extensive decline of a variety of nonvertebrate and plant groups, despite their numerical dominance and ecological importance, highlights the urgency to protect less charismatic organisms (13–18).

While developing strategies to counteract the persistent drivers of biodiversity loss is critical, determining priorities and sensibly allocating resources remains challenging for a number of reasons. First, fundamental taxonomic and ecological knowledge is scarce for the majority of species (e.g., arthropods, fungi) and many of these are yet to be scientifically described, hindering our ability to assess and address their conservation needs (19–21). Second, knowledge of threat levels to different taxa is not evenly distributed. The IUCN Red List is the global standard for the conservation status of species, yet while it covers ~91% of vertebrate species, it only includes ~1.1% of described insects and 21% of plants (2024; 18, 22). Such bias has direct implications for conservation decisions, species management, and funding allocation (23, 24) but, to date, there have been few attempts to assess the allocation of this funding to global efforts to conserve species. Third, traditionally, literature reviews have been used to assess the distribution of conservation efforts (4–11, 25, and 12 for a regional example). However, scientific publications may not fully represent conservation efforts. Conservation funds are often directed toward on-the-ground actions which rarely lead to scientific publications or, if published, are in local journals or project reports for funders and NGOs, and frequently not in English. The usefulness of literature reviews is also limited as most focus on higher taxonomic levels [e.g., such as vertebrate/invertebrate/plants (4, 6–11)] rather than on species. This approach prevents the detection of mismatches between taxa that have received conservation attention versus those that warrant support [but see (25, 26)]. Finally, literature-based information is often disconnected from the amount of funding allocated, which is key in evaluating how various taxa are being supported relative to their IUCN Red List status, and the overall level of resources being invested into conservation. We argue that understanding the distribution of species-level funding provides a powerful tool to inform recommendations of how resources can be distributed more effectively.

Thus, we compiled an extensive database on funding for the conservation of species (number of conservation projects focusing on particular taxa and their funding) from supranational organizations, government agencies, and international NGOs (one supranational conservation scheme, 7 governmental agencies, 28 I-NGOs and 1 crowdfunding; totaling 14,611 projects). We examined the “conservation effort” (number of projects and funding support) across different taxonomic groups and their trends over time between government agencies and I-NGOs to determine the diversity of species that have received funding during a 25-y period (1992-2016). We then looked at whether funding was mainly directed toward threatened species, equally distributed among species, or skewed toward a small pool of species. We also explored whether trends in funding charismatic taxa are warranted based on recently recorded extinction rates and the relationship between funding rates and project “success” as indicated by the percentage of species showing population increases.

Results

Resource Distribution: High Taxonomic Levels.

Information was compiled from 14,566 projects (45 projects lacking funding information), representing a total of US $1.963 B, in which governmental agencies represented 78.3% of the funding available but just one-third of the projects.

Although we anticipated that most funds would be directed to vertebrates (4–11), this bias was larger than expected. We found that 82.9% (US $1.627 B) of the funding and 84% of all projects were allocated to vertebrates (Table 1), 10 to 40% higher than previously reported in literature-based reviews [e.g., 69% (4), 43% (6); 75% (11)]. Plants and invertebrates each accounted for only 6.6% of the allocated funding (US $129 M) and 7.8% and 5.7% of the projects, respectively; with fungi and algae barely represented (<0.2% and <0.1% of funding, respectively, SI Appendix, Table S1). The majority of projects (57%) and funding (53%) targeted single rather than multiple species, almost double the estimates derived from literature-based assessments [~34% (8)]. In the most recent period analyzed (2012–2016), 60.6% of the projects and 49% of the funding were still directed toward individual species.

Table 1.

Total number of assessed projects and funding allocated per higher taxonomic group from governmental agencies and I-NGOs in the assembled database

	Number projects supported (% total)			Funding allocated in US $ M (% total)
Taxonomic group	Gov.	I-NGOs	Total	Gov.	I-NGOs	Total
Algae	11 (0.2)	3 (0.03)	13 (0.1)	1.3 (0.08)	0.03 (0.01)	1.3 (0.07)
Fungi	9 (0.2)	45 (0.5)	54 (0.4)	2.7 (0.2)	0.5 (0.12)	3.2 (0.16)
Invertebrates	227 (4.5)	611 (6.4)	818 (5.7)	89. 9 (5.8)	39.7 (9.3)	129.6 (6.6)
Plants	352 (7)	793 (8.3)	1,209 (7.8)	92.8 (6)	36.3 (8.5)	129.1 (6.6)
Vertebrates	4,328 (86.4)	7,940 (82.7)	12,194 (84)	1,289.1 (83.8)	337.9 (79.4)	1,627 (82.9)
Multiple taxa	83 (1.7)	209 (2.2)	278 (2)	62.2 (4)	11.1 (2.6)	73.3 (3.7)
Total	5010	9,601	14,611	1,537.9	425.6	1,963.5

Despite identifying disparities in funding allocation, previous assessments solely based on higher-taxonomic ranks (4, 6–11) concealed important differences within and among taxa. Within the vertebrates, for example, mammals and birds receive 70 to 85% of total resources, yet amphibians receive less than 2.8% of funding (Fig. 1). Even within one of the best-funded and studied groups, the mammals, large disparities exist. Species-rich taxa like rodents (Rodentia), bats (Chiroptera), kangaroos and wallabies (Diprotodontia), or hedgehogs (Eulipotyphla) receive limited funding despite including numerous threatened species (Fig. 2). Large-bodied taxa (e.g., Primates, Carnivora, Cetaceans, elephants, rhinoceros), which represent only a third of threatened mammals, account for nearly 84% of projects and 86% of funding (Fig. 2), 25% higher than previously reported [SI Appendix, Fig. S3 (25, 26)]. In reptiles, this pattern is more apparent with turtles and tortoises (Testudines) accounting for 91.4% of funding, and 87% of the funding directed toward seven species of marine turtles alone. Conversely, diverse and threatened groups of Squamata (e.g., lizards, snakes, geckos, or chameleons) are largely under-represented (Fig. 3). Within birds, groups such as diurnal raptors (Accipitriformes, Falconiformes) receive relatively more funding than other taxa (SI Appendix, Fig. S2). For invertebrates, available resources are severely limited but also unbalanced. Most of the funding for insects goes to pollinating Hymenoptera (Anthophila—38.4%), butterflies (28%), and large Coleoptera (25.7%—mostly fireflies, longhorn, and scarab beetles); with the two orders including 47.4% of threatened species (i.e., Orthoptera and Odonata) receiving only 2.4% of the available funding (US $ 603,000; Fig. 4).

Fig. 1.

Variation over time of the percentage of funded single-species conservation projects (A) and funds received per taxonomic group (B) for the period 1992–2017. Taxonomic groups are, for vertebrates (plain lines): amphibians (lighter gray), birds (dark gray), fishes (blue), mammals (dark), and reptiles (light gray); for invertebrates (dashed lines): arthropods (orange) and nonarthropod invertebrates, e.g., molluscs (yellow) and for nonanimal groups (dotted lines): plants (green) and fungi + algae (red). The total number of funded projects A) and the total amount of funds received in millions of US $ B) for each taxonomic group is presented on the Right y-axis. For each 5-y period, the number of projects and of funding agencies (in parentheses) A) and the total funding amount B) are presented on top of the chart.

Fig. 2.

Percentage of species richness (Right, green bars) and of threatened species (Right, yellow bars), and percentage of projects (Left, blue bars) and funding (Left, gray bars) invested for mammalian orders. Artiodactyla are divided into noncetaceans and cetaceans. Orders representing less than 2% of the categories included here (Afrosoricida, Cingulata, Dasyuromorphia, Didelphimorphia, Lagomorpha, Macroscelidae, Microbiotheria, Monotrema, Peramelemorphia, Pholidata, Pilosa, Scandentia, and Sirenia) have been combined under the Other orders category for visualization purposes. On the Right side, numbers besides green and yellow bars indicate the total number of species, and of threatened and extinct species, respectively, for each order, while on the Left side, numbers besides blue and gray bars represent the number of projects and the funding (in millions of US $), respectively, for each order.

Fig. 3.

Percentage of species richness (Right, green bars) and threatened species (Right, yellow bars), and percentage of projects (Left, blue bars) and funding (Left, gray bars) invested for reptile groups: true lizards, snakes, geckos, turtles, chameleons, and crocodilians. On the Right side, numbers besides green and yellow bars indicate the total number of species, and of threatened and extinct species, respectively, for each order, while on the Left side, numbers besides blue and gray bars represent the number of projects and the funding (in millions of US $), respectively, for each order.

Fig. 4.

Percentage of species richness (Right, green bars) and of threatened species (Right, yellow bars), and percentage of projects (Left, blue bars) and funding (Left, gray bars) invested for insect groups: Coleoptera, Diptera, nonbutterflies Lepidoptera, Hymenoptera (excluding Antophila—pollinators), Hemiptera, Orthoptera, Antophila (pollinators), butterflies, Blattodea, and Odonata. On the Right side, numbers besides green and yellow bars indicate the total number of species, and of threatened and extinct species, respectively, for each order, while on the Left side, numbers besides blue and gray bars represent the number of projects and the funding (in millions of US $), respectively, for each order.

Resource Distribution: Species-Level.

Single-species projects covered 2,335 species (Gov.: 455; I-NGOs: 2109), including 1,505 currently considered as threatened (Gov.: 281; I-NGOs: 1408), 547 as nonthreatened (Gov.: 138; I-NGOs: 443), and 292 as data deficient or not evaluated (Gov.: 36; I-NGOs: 258). Only 6.2% of the 24,422 species considered as globally threatened by the IUCN Red List in 2018 have been the focus of a project included in our dataset. Of single-species projects, 57.2% of the funding targeted threatened species (Fig. 5), yet over a third (US $390 M) was allocated to species in the lower categories of the IUCN Red List, including 29% for species of “least concern.”

Fig. 5.

Distribution of support for single-species projects for the period 1992–2016 as a function of their IUCN Red List conservation status for (A) total funding (percentage in parentheses), (B) by categories of funding received per species (number of species indicated within each bar), (C) percentage of projects per taxon and (D) percentage of funding received per taxon. Color codes for IUCN Red List categories are red for extinct species (EX + EW), yellow for threatened species (CR+EN+VU), green for nonthreatened species (NT+LC), and gray for species with uncertain status (DD+NE). Numbers on the Right y-axis indicate the total number (C) or funding (D) for projects for mammals, birds, reptiles, fishes, amphibians, arthropods, nonarthropods invertebrates, plants, and algae+fungi.

Almost half of the resources available were directed to a subset of 47 species (38 mammals, 4 marine turtles, 2 trout, 1 bird of prey, 1 pine tree, and 1 butterfly, SI Appendix, Table S2) totaling 40.5% of all single-species projects (totaling 3,411 projects) and 39% of the funding (US $404 M); with the largest share directed to Asian (Elephas maximus) and African bush elephant (Loxodonta africana) with 556 (US $38.3 M) and 505 projects (US $29.3 M), respectively. These most supported species (SI Appendix, Table S2) had a median funding per project of US $51,575, whereas species which were funded only once had funding more than five times lower (U.S $9,402; SI Appendix, Table S3). Additionally, 10 of the 47 most supported species are not considered under the threatened categories of the IUCN Red List (e.g., gray wolf, Canis lupus—US $24 M; brown bear, Ursus arctos—US $43.7 M) but accounted for 519 projects (US $138.4 M).

Are Well-Funded Taxa Doing Better?

Assessing population trends is challenging, as few species have been subjected to systematic inventories across their range [apart from a few large-bodied mammals such as pandas (27)]. We used the Living Planet Index database (28) to assess the number of populations showing increases or decreases for 341 species with funding data. Trends were very heterogeneous, but there was no significant relationship between total funding for a species and the percentage of populations showing increases for any time period considered (1990–2010, 2000–2010, and 2000–2020).

Discussion

Species extinctions are continuing at an alarming rate globally (29). To limit this erosion of biodiversity, there is a fundamental need to increase funding for conservation. Estimates suggest that US $3.41 to 4.76 B is needed annually to mitigate extinction risks for threatened species (30), while US $400 B would be required to conserve threatened species and their habitats (31). Although our database did not include habitat-based conservation programs (32, 33) and has other limitations (SI Appendix), it nonetheless shows that investments in species-focused conservation fall short of these estimates by two orders of magnitude (~US $78.5 M per year). Assessing the allocation of funding, and how it aligns with identified priorities (such as threatened species, and effectiveness) is thus essential to ensure that the limited funds are used as effectively as possible.

Given the widespread use and recognition of the IUCN Red List (the “Barometer of Life,” 34) to identify which species are most in need of conservation efforts, the most parsimonious approach would be to allocate funding based on IUCN threatened species status or other known indicators of vulnerability (such as small range size). Our results demonstrate that this is not the case and a significant proportion of resources are used for nonthreatened species and allocated to a limited subset of species. While our dataset may not capture all national conservation efforts, similar trends have been detected in other countries, such as China or India, where most funding is directed to large mammals and birds (35, 36). This biased distribution of funding results in a strong mismatch between established, scientifically derived criteria to identify threatened species and the allocation of funding to assess and counteract those threats. For example, small-bodied taxa, such as amphibians, have been known to be the most threatened of vertebrate groups for two decades (7, 22, 37, 38), accounting for ~25% of the threatened vertebrate species (22). Yet, amphibians received only 2.5% of recent funding, which declined from 4% in the late 1990’s. Furthermore, amphibians differed from other vertebrate groups as most projects on amphibians targeted multiple species, limiting the investment per species (SI Appendix, Fig. S1). Similarly, weak conservation efforts are observed within many groups of mammals (e.g., Rodentia, Chiroptera), reptiles (e.g., Squamata, Serpentes, or nonmarine Testudines), or insects (e.g., Odonata, Orthoptera) despite the well-known threats to these taxa. In some instances, however, such as in the Australian Diprotodontia, local conservation efforts may have been poorly captured here as funding likely originates from regional or community-funded efforts (39) not included in our dataset.

In contrast, a subset of species received a disproportionate share of the funding, still likely underestimated in our results. Several larger funds not included in our dataset are dedicated to single or small groups of species, such as the >US $33.4 M allocated for elephant research since 2013 through the Elephant Foundation (40), on top of the direct UN funding coming from bodies such as ITIS and MIKE. The need for this continued funding is questionable when African elephant conservation programs have been so successful that contraception programs have been initiated for some populations to prevent further population growth (41). Paradoxically, methods to counteract the “funding gaps” often amplify these biases with, for example, species-specific “biodiversity bonds” for the already well-funded rhinoceros, lions, and other large felines (42, 43, SI Appendix, Table S2).

The focus on charismatic species to generate funding and public support (44, 45) has led to inadequate support for a large majority of “less-charismatic” but threatened species. Previous studies have highlighted that “charisma” and body size are often the greatest predictors of funding (46). Yet, the charismatic flagship species (typically large-sized mammals and birds) are generally poor proxies for the abundance and distribution of other species (44, 46–52). Charismatic species are often poor indicators for range-restricted or more specialist taxa (52) and may fail to provide an adequate indicator for entire taxonomic groups (especially plants and invertebrates; 53, 54). This poor overall representation of other species, therefore, limits the effectiveness of charismatic species as umbrella species (55) and means significant funding is expended on a limited selection of species, providing few benefits to conservation more broadly (36, 56).

Finally, funding was, in general, not associated with increases in populations for the subset of species for which monitoring data exists. In contrast, some of the groups with the highest rates of documented extinctions in recent periods, such as freshwater gastropods, present some of the lowest levels of funding. IUCN Red List records on documented extinctions (22) show that gastropods constitute 29% of recent extinctions, 10.5% of possible extinctions, and 19% of extinct in the wild records; followed by birds (17.5% extinctions, 1.7% possible, and 6% of extinct in wild), then Magnoliopsida (11.8%, 36.3%, and 38%), and Actinopterygii (9%, 10.7%, and 13.1%). Collectively, these findings highlight the persistent gaps in funding for all but a subset of taxa, the inefficient nature of current funding models, and the desperate need to review priorities for future funding allocation.

Future allocation of funding needs to address these biases by distributing resources to a wider range of vulnerable species. A broader taxonomic focus in conservation would also allow the protection of a greater range and scale of habitats, some of which may no longer harbor charismatic vertebrate species (44) but still act as refuges for other less conspicuous species (57). The assessment of neglected and highly threatened taxa (e.g., invertebrates), with <1% of described arthropods assessed by the IUCN Red List (14, 22), and their conservation should be seen as an urgent priority. The suggested development of an international center to assess and monitor conservation status of invertebrate species (15) could lead to global assessments for 75% of described Eukaryotes. If national efforts have recently emerged (e.g., Germany), those need to be expanded further to other nations, in parallel to other protective measures (58). Considering the roles of these species in ecosystems and for our societies (59), leveraging potential conservation actions toward taxa representing three-quarters of biodiversity could provide considerable benefits.

Government agencies have a particularly important role to play as they provide most of the funding, but currently exacerbate taxonomic biases (Table 1). To be more effective, governments should develop a more holistic view of conservation and use objective scientific criteria to allocate funds. Beyond this, I-NGOs, which are assumed to be biased toward more “marketable” species (44, 45, 60), should also consider realigning their priorities toward actual threats. Global and supranational efforts are needed to coordinate funding which could include incentivizing proposals on poorly studied groups and curbing funds for overfunded groups. Better coordination among agencies, coupled with increased transparency to limit redundancy in funding allocation, represent other potential avenues to explore. With numerous independent projects on similar species, the risk of redundancy is high, which is unacceptable given the limited funding available. A potential solution is to compile global conservation efforts into a single public database to coordinate conservation efforts and facilitate the identification of major priorities and gaps for both governments and I-NGOs. Our work represents a potential step in that direction but should be expanded to include further governmental structures, including local-level agencies, NGOs, and other institutions.

Realigning funding to better support neglected taxa would also offer a clearer understanding of the magnitude of the current extinction crisis (29, 61, 62) and its primary causes, such as habitat change and biological invasions (7, 10, 63). This strategy would reduce the misallocation of limited resources toward secondary causes driven by a narrow focus on charismatic species facing specific threats (e.g., the wildlife trade). A more inclusive taxonomic approach would also enhance public perception. For instance, successful citizen-science programs, even for taxa not typically seen as charismatic, have already spurred an increase in local and applied actions (64, 65), as many individuals may feel geographically disconnected from some of the large megafauna that receive the “lion’s share” of funding (46).

Despite decades of conservation efforts, the majority of monitored taxa continue to show declining populations, including species that have already received substantial funding for many years. Ultimately, reducing or halting biodiversity loss will depend on sufficient resources across taxa to enable targeted actions and monitoring trends. Currently, the limited funding available is primarily allocated to a small subset of taxa, with most taxa receiving no funding despite the ongoing gaps in knowledge for these groups. With heightened awareness of the essential functions and services of many species that are often seen as less charismatic, it is crucial to address these biases and optimize the allocation of funds to ensure the protection of these species.

Materials and Methods

Data Preparation.

While financial resources are dedicated to the conservation of habitats, ecosystems, or particular regions (32, 33, 66), many grant agencies, either governments or INGOs, remain primarily dedicated to the conservation of species. The substantial funding and efforts directed toward species, and the results emerging from those efforts, are of importance to either measure the success of species conservation per se or to guide which particular habitats or regions should be protected (e.g., areas with endemic birds). Evaluating the species level efforts and funding engaged is thus paramount to evaluate how biodiversity is assessed and prioritized in the conservation arena.

We extracted data on funds awarded to conservation-based research projects from 36 funding bodies globally, including eight governmental agencies and twenty-eight International Non-Governmental Organizations (I-NGOs). Only projects funded from 1992–2016 for which project descriptions were available were used to generate the database (14,566 projects in total; see supplementary material for details on database development). The budget allocation for each project was standardized for analyses by converting all budget values into US$ for 2017 using the average international currency exchange rates for the year of project commencement and applying an inflation correction to 2017. Data on funding were only available for 91% of the projects (13,293 projects). Thus, the datasets for analyses of distribution of financial support among taxonomic groups differ slightly from that of the distribution of the total number of projects.

To construct the database, several variables were extracted for each project: the name and type of organization (governmental or I-NGO); the geographic location of both the project and the funding recipient; the commencement date; the funding amount; and the number and identity of the focal species (SI Appendix). The taxonomic validity of focal species was verified to ensure that each species was listed under its most recent name, with higher taxonomic levels standardized to reflect the current consensus. Projects were categorized as either single- or multiple-species based on the number of species targeted. This binary classification was necessary because multiple-species projects did not always provide detailed descriptions of the number of focal species (e.g., “Conservation of montane forest anurans”); thus, a continuous classification or regression approach could not be employed. In contrast, single-species projects always clearly identified the focal species. For multiple-species projects, it was assumed that the allocated funding was evenly distributed among the different species, whereas in single-species projects, all funds were assumed to be directed solely toward the focal species.

For taxonomic analyses, three main classifications were adopted due to the nature of the available data. The first predominantly used classes for vertebrates (amphibians, birds, mammals, reptiles) or simplified groupings such as fishes, arthropods and nonarthropod invertebrates, plants, and fungi (together with algae). Although taxonomically inaccurate (with the presence of non-monophyletic groupings), this clustering allows analysis of resource distribution among groups and comparisons with previous studies using similar classifications. Second, we used a more taxonomically accurate classification based on the ordinal level within each class, specifically for Mammalia, Reptilia, and Insecta. A few exceptions were made with the use of the Cetacean infraorder (separated from Artiodactyla); Anthophila (separated from Hymenoptera) for pollinator insects; and Rhopalocera (butterflies), to highlight the importance of these groups in conservation funding. This classification allowed the use of 97%, 95%, and 88.5% of the projects including only mammals, reptiles, and insects, respectively. Finally, the third analysis was performed at the species level, with the validity of each species checked for synonymy to retain only valid taxonomic names at the time of analysis. For the species-level analysis, only single-species projects (8,365 projects) were used to prevent potential errors and arbitrary division in the allocation of funding among species within a multiple-species project.

Threat Levels and Diversity Data.

The IUCN Red List assessment, established in 1964, was used to assess the conservation threat level of the focal species as it uses widely accepted criteria and has been used extensively (34, 37, 38). Data on the conservation status of all species in the database were downloaded from the IUCN website (22 November 2017) and used to assess the level of threat to each species. While a discrepancy in the IUCN Red List status of a species between the time of a project approval and the status of the species in 2017 might exist, our approach can be perceived as conservative as most species are likely to have their status downgraded (increased threat) rather than upgraded over time (see examples with vertebrates; 2). From a total of eleven conservation status categories initially retrieved, including some that are no longer in use (e.g., LR/lc), each species was ultimately associated with one of the nine current categories. These were grouped into four larger categories, namely Extinct (EX: extinct, EW: extinct in the wild), Threatened (CR: critically endangered, EN: endangered, VU: vulnerable), Lower Risk (LC: least concern, NT: near threatened), and Unknown (DD: data deficient, NE: not evaluated), a classification system commonly used in previous studies (26, 37). Species diversity data for the different taxa (mainly ordinal level) of mammals, reptiles, and insects were obtained from various literature sources (67–69). The percentage of threatened species was then calculated for each taxonomic group.

To identify the species receiving the highest conservation efforts, we established a cumulative threshold of 20 independent projects (i.e., not continuations of previous projects) focusing on a single species over the 25-y period covered by our study, independent of the funding amount received (i.e., there was no funding threshold). Because project descriptions involving multiple species did not allow the identification of all focal species, the selection of the species receiving the highest conservation efforts was based only on single-species projects. As a result, our estimates are likely to be conservative as this subset of species is also represented in multiple-species projects.

The Impact of Funding on Contemporary Conservation Status.

Since overall population data are available only for a minority of species, the Living Planet Index (28) was used to assess changes in population status at various time periods. The Living Planet Index includes 32,680 populations of 4,923 species, with some populations monitored since 1950 (though much more data is available from 1975 onward). The benefit of this data source is that it attempts to monitor populations, and, therefore, provides a somewhat consistent means of assessing trends over time within populations (different methods are used between populations, therefore overall statistical changes in population may be hard to assess). As the dates of assessment vary, we calculated the maximum population pre-1990 as a baseline, then calculated the maximum population for a species between 1990–2010, 1990–2020, 2000–2010, and 2000–2020/15 (depending on when the latest data was available). For each population we calculated the percentage change over time, then quantified how many populations increased or decreased for each species within each time-period. The percentage of populations increasing for each species was calculated, then paired with the funding data for that species. Given that population data were sparse, and some species only had a single population monitored, the time-periods were plotted separately to assess whether there was any relationship between the percentage of populations showing an increase, and the amount of funding provided using linear regression.

Assessing Past Extinctions.

It is often argued that large-bodied taxa are more vulnerable to extinction. While it is true that such species consume more, and may be at higher trophic levels, their representation in recent extinctions has not been explored. The IUCN Red List not only assesses the threat status of extant species but also includes recently extinct species (generally extending to initial European colonization of areas). Using the IUCN Red List data, we downloaded 1) species listed as extinct (909 species), 2) species listed as possibly extinct (1,302 species), and 3) species listed as extinct in the wild (84 species). In addition, as assessments are regarded as “outdated” when they are over 10 y old, we also downloaded the summary of species where assessments are currently considered outdated (41,403 species—December 2023). The number of species within each genus and family was summarized for each of these to assess the overall taxonomic makeup of recent extinctions.

Supplementary Material

Appendix 01 (PDF)

Dataset S01 (XLSX)

Data, Materials, and Software Availability

All study data are included in the article and/or supporting information.