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Land use change is the most widespread driver of biodiversity loss in densely populated tropical countries. Biodiversity loss, in turn, results in changes in functional guilds responsible for various forest ecosystem services. It is thus necessary to understand the extent and types of biodiversity loss and functional guild alteration caused by land use change in order to facilitate sustainable land use policies. Here we study the effects of land use change on forest bird species and guilds in a human-dominated landscape in the Western Himalaya, India. We carried out systematic breeding-season surveys in six land use types within moist temperate forest: natural (protected) oak forest, degraded (lightly used) oak forest, lopped (heavily used) oak forest, pine forest, cultivation and built-up sites, in two adjoining landscapes, over two consecutive years. Our study shows moderate to drastic species loss in all modified land use types in comparison to natural oak forest. Species composition in modified land use types diverged significantly from natural oak; this effect was highest in cultivation and built-up sites and least in degraded forests. Compositional change in modified land uses occurred due to partial replacement of forest specialists with commensals and open country species, whereas abundance of forest generalists was relatively constant across the gradient. We also find a steep decline in the abundance of functional guilds such as pollinators, and insectivorous pest controllers in all modified land uses in comparison to natural oak forest. Our results have important implications for conservation in biodiverse mountain landscapes with significant human imprint. In particular, (a) low faunal diversity in monocultures and urban sites (b) drastic (50% loss or more) loss of forest specialists, pollinators and insectivores in degraded forests, monocultures and urbanised sites; and (c) the potential for degraded forest as refugia for forest species, are findings that can be globally applied to land use and conservation planning in human-dominated landscapes.
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Decline in forest bird species and guilds due to land use
change in the Western Himalaya
Ghazala Shahabuddin
a
,
*
, Rajkamal Goswami
a
,
1
, Meghna Krishnadas
b
,
Tarun Menon
a
,
2
a
Centre for Ecology, Development and Research (CEDAR), 201/1, Vasant Vihar, Dehradun, Uttarakhand, 248006, India
b
CSIR -Centre for Cellular and Molecular Biology, Uppal Road, Habshiguda, Hyderabad, Telangana, 500007, India
article info
Article history:
Received 23 July 2020
Received in revised form 24 December 2020
Accepted 24 December 2020
Keywords:
Degraded
Deforestation
Urban
Avifauna
Monoculture
Oak
abstract
Land use change is the most widespread driver of biodiversity loss in densely populated
tropical countries. Biodiversity loss, in turn, results in changes in functional guilds
responsible for various forest ecosystem services. It is thus necessary to understand the
extent and types of biodiversity loss and functional guild alteration caused by land use
change in order to facilitate sustainable land use policies. Here we study the effects of land
use change on forest bird species and guilds in a human-dominated landscape in the
Western Himalaya, India. We carried out systematic breeding-season surveys in six land
use types within moist temperate forest: natural (protected) oak forest, degraded (lightly
used) oak forest, lopped (heavily used) oak forest, pine forest, cultivation and built-up
sites, in two adjoining landscapes, over two consecutive years. Our study shows moder-
ate to drastic species loss in all modied land use types in comparison to natural oak forest.
Species composition in modied land use types diverged signicantly from natural oak;
this effect was highest in cultivation and built-up sites and least in degraded forests.
Compositional change in modied land uses occurred due to partial replacement of forest
specialists with commensals and open country species, whereas abundance of forest
generalists was relatively constant across the gradient. We also nd a steep decline in the
abundance of functional guilds such as pollinators, and insectivorous pest controllers in all
modied land uses in comparison to natural oak forest. Our results have important im-
plications for conservation in biodiverse mountain landscapes with signicant human
imprint. In particular, (a) low faunal diversity in monocultures and urban sites (b) drastic
(50% loss or more) loss of forest specialists, pollinators and insectivores in degraded for-
ests, monocultures and urbanised sites; and (c) the potential for degraded forest as refugia
for forest species, are ndings that can be globally applied to land use and conservation
planning in human-dominated landscapes.
©2020 The Author(s). Published by Elsevier B.V. This is an open access article under the CC
BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
*Corresponding author.
E-mail addresses: ghazala@cedarhimalaya.org,ghazala@cedarhimalaya.org (G. Shahabuddin).
1
Presently at Ashoka Trust for Research in Ecology and Environment (ATREE), Royal Enclave, Srirampura, Jakkur Post, Bengaluru 560064, India.
2
Presently at Nature Conservation Foundation, Vijay Nagar II Stage, Mysuru, Karnataka 570017, India.
Contents lists available at ScienceDirect
Global Ecology and Conservation
journal homepage: http://www.elsevier.com/locate/gecco
https://doi.org/10.1016/j.gecco.2020.e01447
2351-9894/©2020 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/
licenses/by-nc-nd/4.0/).
Global Ecology and Conservation 25 (2021) e01447
1. Introduction
Land use change is considered to be one of the leading drivers of global biodiversity loss (Young et al., 2016;Maxwell et al.,
2016). Such species losses, which were earlier expressed over long periods of time, have drastically increased in speed and
extent in the Anthropocene primarily due to expanding populations and national economies. An increasing demand for food
has transformed a third of the worlds land surface to agro-pastoral production; of this, half has occurred at the cost of tropical
forests (Díaz et al., 2020). By 2030, 1.2 million km
2
of global land area will be urbanised to accommodate ve billion people
(Seto et al., 2012).
Land use change comes at a huge cost to natural habitats such forests and wetlands (Hansen et al., 2013) and therefore, to
biodiversity (Maxwell et al., 2016). Birds as a taxon have been relatively better studied: numerous studies show loss of bird
species due to land use change across many biomes. For instance, the impacts of land use change on bird diversity have been
studied in various geographic contexts such as Amazon basin (Barlow et al., 2007;Srinivas and Koh, 2016), Eastern Himalaya
(Mandal and Shankar Raman, 2016), Western Ghats in India and Sri Lanka (Sreekar et al., 2015) and Mexican highlands
Carillo-Rubio et al., 2014). Declines in species abundance can be related largely to reduction in structural complexity and
resources of forest habitats as well as alterations in predator-prey and competitive relations (Sol et al., 2020;Menon et al.,
2019;Shochat et al., 2006).
Land use change additionally leads to divergence in species composition caused by selective loss and decline in species and
functional guilds that are more vulnerable than others (Menon et al., 2019;Sreekar et al., 2015;Srinivas and Koh, 2016).
Recent global scale meta-analysis (Newbold et al., 2015;Sol et al., 2020) and predictive modelling exercises (Hinz et al., 2020;
Seto et al., 2012) have revealed the patterns of avian loss in terms of vulnerable species and guilds. Differential vulnerability of
species and guilds depends on degree of resource specialisation, primary foraging substrate, population resilience as well as
dispersal ability, among other factors ( De Lima et al., 2013;Menon et al., 2019;Srinivas and Koh, 2016;Newbold et al., 2013).
For example, forest specialists and insectivores tend to decrease (Menon et al., 2019) while commensal species and granivores
tend to increase in abundance in intensively used landscapes (De Lima et al., 2013;Shochat et al., 2006).
Avian community change, in turn, can have signicant repercussions on forest ecosystem function (Gaston et al., 2018). For
instance, decline in population of certain bird species has been linked to decline in critical ecosystem services such as
pollination, biological pest control and seed dispersal (Whelan et al., 2015;Maas et al., 2013). Recent meta-analyses also
indicate signicant alteration in functional guild abundance and composition due to land use change (Newbold et al., 2020;
Sol et al., 2020). Empirical studies quantifying abundance and composition of such functional guilds in managed forests and
alternative land uses in specic biomes, are urgently required because avian population declines can signicantly affect
ecosystem processes (Whelan et al., 2015;Maas et al., 2013;Gaston et al., 2018). It is for this reason that scholars emphasize
the importance of documenting not just species losses, but also abundance declines in species, a process termed as defau-
nation(Young et al., 2016).
The Himalayas and their terrestrial ecosystems, have been recognised as a global biodiversity hotspot owing to high
species richness and endemism, as well as high levels of threat due to land use changes (Mittermeier et al., 2004). Himalayan
forests and their biodiversity are threatened by expanding forest modication, degradation and conversion to other land uses
as well as climate change (Pandit et al., 2007,2014). Furthermore, there are few strictly protected areas except in the highest
reaches of the alpine zone. While agricultural land uses have been studied to some extent in the Himalayas (Elsen et al., 2017),
there is still little information on the diverse array of other land uses such as new types of monocultures, expanding urban
centres and intensively extracted forests (Pandit et al., 2014). In this paper, we examine the effects of land use change on bird
assemblages in forests of Western Himalaya, as well as the relative vulnerabilities of various habitat and functional guilds.
We hypothesised that both bird species richness as well as the degree of community similarity to natural forest stands,
would decrease along the land use intensication gradient. We then examine the effect of land use change on various habitat
guilds of birds in the study landscape, expecting a decrease in forest specialists, little or no change in forest generalists and an
increase in commensals and open country species along the land use intensication gradient. Finally, we assess the effect of
land use change on the abundance of three avian functional guilds - pollinators, ecosystem engineers and insectivorous pest
controllers. All three groups of ecosystem service providers are signicant for agricultural activity. Pollinators help in
fertilizing crops and fruit-trees; ecosystem engineers (primarily barbets and woodpeckers) expand the niches available for
insectivorous birds, while insectivorous birds provide biological control on insect pests in eld and orchards (Sekercioglu
2006).
2. Materials and methods
2.1. Study area
Our study was focussed on the natural oak-dominated forests occurring between 1500 and 2400 m asl in the Western
Himalaya, dominated by Quercus leucotrichophora,Q. oribunda and other oak species. Such forests form part of the Western
Himalayan moist temperate forest biome as well as an Endemic Bird Area (Birdlife International, 2016). Himalayan oak forests
host high bird diversity due to their complex vegetation structure, evergreen nature, species-rich ora, dense leaf litter and
moist micro-climate (Shahabuddin et al., 2017).
G. Shahabuddin, R. Goswami, M. Krishnadas et al. Global Ecology and Conservation 25 (2021) e01447
2
A 1285 km
2
study area was selected for study within the oak-dominated forests, bounded by the latitudes 29.48 and
29.37 N, and longitudes 79.35 to 79.67 E between the altitudes of 1700 me2400 m (Fig. 1). In the oak forests, Q.oribunda and
Q.leucotrichophora occur as the dominant species in the late-successional oak forest, along with associates such as Rhodo-
dendron arboreum,Lyonia ovalifolia,Myrica esculenta and Aesculus indica. Two separate landscapes separated by 5 km, were
chosen for detailed study: Landscape A was centred around the town of Mukteshwar and Landscape B was around Pangot
village (see Fig. 1). Both landscapes had adequate representation of the six different land use types in this region as well as
substantial natural oak forest area.
2.2. Selection of study sites
Six major land use types were identied in the study area based on degree and type of anthropogenic use and are
described below in increasing order of use intensity and modication of natural habitat (see also Fig. 2a,b,c and Fig. 3a,b,c for
photographs of each land use category).
Natural or protected oak forest (hereafter natural oak) represents the natural forest of that landscape with no recorded
history of felling or management (Fig. 2a). Degraded oak forest (hereafter degraded oak;Fig. 2b) represents lightly used
forest from where re-wood, leaves and leaf litter are collected. Such forests show poor understorey and leaf litter layer, fewer
large/tall trees but a moderately intact canopy cover. Heavily degraded or lopped oak forest (hereafter lopped oak;Fig. 2c),
represents forest with highest intensity of use, primarily, leaves harvested for cattle feed. Such forests have poor canopy,
heavily lopped trees, no leaf litter and high densities of stumps and coppices. Our delineated land use classes were based on
both visual observation, but also on the well-studied disturbance regimes present in the study area (see Thadani and Ashton
1995). However, in order to conrm that our visual classication on the basis of presumed use intensity was useful, we
quantied two variables related to disturbance in each of the study sites (see below): extent of leaf litter collection and extent
of tree-lopping. The graphed data can be seen in Appendix A, and conrm that the three oak forest classes were quantiably
different from each other in intensity of use.
Pine forest comprises of primarily chir pine (Pinus roxburghii), an early successional native species, occurring in largely
mono-dominant stands. Pine forest shows low tree density and poor canopy and grows on poor soils (Fig. 3a). There is ev-
idence that pine forests are expanding in area at the cost of the oak forests due to chronic use, frequent re and warming
(Naudiyal and Schmerbeck 2017;Shahabuddin and Thadani 2018). Pine forests are often burnt for fodder, and used for
extraction of pine needles and pine resin. Cultivation sites represent a mix of subsistence and cash-cropping where fruit trees
Fig. 1. Map of the 198 study sites in the two neighbouring landscapes in the Western Himalaya, where breeding bird surveys were done using similar protocols in
2016 (Landscape A) and 2017 (Landscape B).
G. Shahabuddin, R. Goswami, M. Krishnadas et al. Global Ecology and Conservation 25 (2021) e01447
3
coupled with seasonal vegetables and grains are cultivated along terraces (Fig. 3b). Built-up sites are semi-urbanised land-
scapes, comprising clusters of village houses, tourist resorts and summer homes often separated by fallow areas, fruit trees
and private gardens (Fig. 3c).
In Landscape A,138 study sites were selected, with 23 in each of the six land use categories. In Landscape B, 60 study sites
were selected with 10 in each land use category. Thus, there were 198 study sites in all, distributed equally over the six
delineated land use categories. Each study site had a homogeneous land use buffer of at least 50 m and was located at least
200 m from the next nearest site. The study sites in each land use category were spatially well-distributed without any
clustering of sites belonging to one category. Metadata on each of the 198 sites are given in Appendix B and Appendix C,
corresponding respectively to Landscape A and Landscape B.
2.3. Data collection
We surveyed bird communities twice in each study siteduring the breeding season of 2016 in Landscape A (April 2 to June
7, 2016). Given resource constraints, our surveys were limited to the breeding season because birds are far more specicin
their resource needs during this period rather than during winter (eg. Kumar et al., 2011). In Landscape B, we surveyed bird
communities twice in 2017 (April 17 to May5, 2017), using point counts. At any given site, the two replicate counts were done
with a gap of 10e14 days during the eld season, in order to account for any weather variation during the season. Both
landscapes could not be covered during the same year due to the brief breeding period for birds (March to May) in Western
Himalaya. During a bird count, birds seen or heard within a 30m radius of the central point were identied and recorded over
a period of 15 min, after a 5-minute rest period. Species were visually identied using a well-known eld guide for birds of the
Indian subcontinent (Grimmett et al., 2011). Unfamiliar bird calls were recorded in the eld and later identied using the
online resource Xenocanto(Xeno-canto, 2020). Bird observations started at sunrise (0700 h) and went on until 1000 h, to
match periods of maximal bird activity. Bird nomenclature was revised based on a peer-reviewed list that incorporates all
recent world-wide nomenclatural changes for Indian species (Praveen et al., 2016). Bird surveys were carried out by the same
observer (RG) throughout the study, thus minimising observer-caused biases. It was assumed that detectability of birds did
not vary across different habitat categories, as birds were actively vocalising during the breeding period, even if they were not
easily visible.
Fig. 2. Images of (a) natural oak forest, (b) degraded oak forest (lightly used), and (c) lopped oak forest (intensively used) that were studied as three distinct land
use types in the Western Himalaya, India.
Fig. 3. Images of the three non-oak land use types studied for birds in Western Himalaya: (a) pine forest, (b) cultivation and (c) built-up sites. Detailed de-
scriptions are in the text.
G. Shahabuddin, R. Goswami, M. Krishnadas et al. Global Ecology and Conservation 25 (2021) e01447
4
2.4. Data analysis
Bird species records were totalled over the two temporal replicates for each site and a species-site matrix was created,
summarizing the abundance of each species in each of the 198 study sites. A separate species-site matrix was created for each
of Landscapes A and B. Species data from the two landscapes were analysed separately as they were from two different years
and were surveyed using variable number of spatial replicates (23 in 2016 and 10 in 2017). Rarefaction analysis was carried
out to nd out if there had been adequate sampling in each of the two study landscapes following Colwell et al. (1994).
Species richness in each land use type was estimated using rarefaction analysis (using the bootstrapping estimator), with
sites as replicates, following Colwell et al.(1994). This method allows for the fact that the species-effort curve for a given site
may not have levelled off completely during the study; species may remain to be discovered. Species estimates using rare-
faction are generally higher than the observed species richness due to this reason. Since Landscape B appeared to be inad-
equately sampled based on the rarefaction curves (see Results), mean species richness per site (cumulative number of species
sighted during the two replicate counts) was also compared across land use categories using an estimate of variation
(standard error). Since the time and effort per count was standardized, species richness per site can be considered robust
estimates of species richness, in the absence of incomplete sampling of bird species.
In order to assess differences in species composition among land use types, we used non-metric multidimensional scaling
(NMDS) following Clarke and Green (1988). The stress value for each NMDS was calculated in order to assess its usefulness,
with low values being preferred. In NMDS graphs, each ellipse (with its centroid) corresponds to a given land use category and
the distance between any two centroids signify degree of dissimilarity in species composition between them. The size of each
ellipse shows the degree of dissimilarity among sites within a given land use category. We then quantied compositional
divergence using Permutational Analysis of Variance or PERMANOVA, using both abundance-based Bray-Curtis and
incidence-based Jaccard indices (Anderson et al., 2006). The two indices allowed us to discern whether patterns in species
richness were being driven by species relative abundances or just presence-absence of species. Statistical signicance of
among-group similarity was assessed by permuting the matrices 999 times and generating the P-value for signicance. An
alpha of 0.05 (p-value) was used as the threshold to assess signicance of the PERMANOVA tests for species composition. We
conducted all community analyses for diversity and species composition using packages hierDiversity(Marion et al., 2015)
and veganin R Software version 3.3.0 (Oksanen et al., 2011).
In order to understand the relative extinction vulnerability of forest bird species based on habitat guilds, we assigned a
category of habitat preference to each species based on two widely used eld guides (Ali, 2012;Grimmett et al., 1998.A
species was assigned to one of the following guilds: oak forest specialist (seen primarily in dense hardwood forest), forest
generalist (species using secondary forest and horticulture in addition to dense hardwood forest), open country species
(species seen primarily in cultivation, grasslands and other open areas) and commensal species (largely found in and around
human settlements). Appendix D shows the assignment of guilds to each of the detected bird species. It should be noted that
habitat preferences of bird species in our eld site, may be different from those that seen at other altitudes or vegetation zones
within the Himalayas, particularly during non-breeding season. We then used histograms to visually compare the total
abundance of species belonging to each habitat guild, combined over the two landscapes.
We assigned ecosystem service categories to bird species based on their documented feeding habits and behaviour,
corroborated by our eld observations (Ali, 2012;Grimmett et al.,1998). The pollinator category comprised of species that had
been observed either feeding on ower nectar, or browsing insects around owers, thus making them likely to pollinate
owers. The pest controller category comprised of all insectivorous birds, irrespective of whether they opportunistically fed
on other items as well (such as fruit or nectar), since such birds would be active in pest control. The category of ecosystem
engineer comprised of all species known to construct cavities for nesting and roosting, such as barbets and woodpeckers.
Functional guild assignments are also given in Appendix D. Abundances of each functional guild were then compared across
land use categories using histograms. Abundance of both habitat guilds and functional guilds were analysed separately for
Landscapes A and B.
3. Results
During the study period, we recorded a total of 8549 bird observations belonging to 124 species, over the 198 study sites in
the two landscapes. In Landscape A, we recorded a total of 110 species and in Landscape B, 98 species were recorded during
the bird surveys. Species abundances are given in Appendix E and Appendix F, corresponding to the two landscapes.
Rarefaction analysis for the two sites showed that the species richness for Landscape A had levelled off with 23 replicates
in each land use, but that sampling effort had not been sufcient for all land use types in Landscape B (Fig. 4a and b).
The species estimates drawn from the bootstrapping analysis showed that in Landscape A, natural oak had the highest
estimated number of bird species amongst all the land use types (78.8 ±2.51; Fig. 4a). Degraded oak, cultivation and lopped
oak showed estimated species richness lower than that seen in natural oak (Degraded oak: 72.9 ±2.81; Cultivation:
67.4 ±2.59; and lopped oak: 68.4 ±3.32 species) representing between 85 and 92% of the species in natural oak. Pine forest
and built-up sites had lowest species richness (pine forest: 56.6 ±2.8 and 57.4 ±2.93 respectively), which was approximately
72% of the species richness in natural oak.
In Landscape B, degraded forests showed similar species estimate as the natural oak, while lopped oak and cultivation
recorded 66e79% of species richness in natural oak. (Natural Oak: 61.3 ±2.53; Degraded oak: 67.2 ±6.14; Cultivation:
G. Shahabuddin, R. Goswami, M. Krishnadas et al. Global Ecology and Conservation 25 (2021) e01447
5
56.8 ±3.8; and lopped oak: 47.7 ±4.14 species). Pine forest recorded 66% of natural oak richness and built up sites recorded
only 36% of the species richness of natural oak (Pine forest: 40.5 ±2.94; Built-up Sites: 23.6 ±2.96). In both Landscapes A and
B, pine forest and built-up sites had the lowest numbers of bird species among all land uses.
Fig. 5 shows the average species number per site in the two landscapes. In Landscape A, natural oak showed the highest
value, followed by the modied forest categories and cultivation sites which recorded 70e75% of the species found in natural
oak. Built-up sites recorded only 48% of the richness recorded in natural oak. In Landscape B, too, natural oak showed the
highest value, but the modied forest categories and cultivation recorded only 50% of the species richness of natural oak (Figs.
4 and 5). Cultivation sites were on par with modied forest categories in Landscape B while built-up sites recorded a meagre
25% of natural oak species richness. In both landscapes, however, the rank order of species-per-site across land use categories
was similar.
Rank order of species-per-site values was similar to that found in the bootstrapped species estimates (Fig. 4a and b), with
the highest values in natural oak, moderate values in the modied forest categories and the least in built-up sites. Cultivation
showed relatively higher richness compared to the modied forest categories in both cases, but still less than natural oak.
The NMDS for both landscapes, shows that bird species composition diverged considerably among forest and non-forest
land uses as shown by the inter-centroid distances (Fig. 6a and b). The stress levels for NMDS in both landscapes were low,
showing the value of the analysis (Landscape A: 0.17; Landscape B: 0.13). PERMANOVA analysis conrmed that all land uses
were signicantly different from each other in terms of species composition. This was shown by both the Bray-Curtis index
(Landscape A: F ¼14.58, p <0.001; Landscape B: F ¼10.34, p <0.01) and the Jaccard Index (Landscape A: F ¼8.53, p <0.001;
Fig. 4. Rarefaction analysis to see the extent of sampling of bird richness in (a) Landscape A , based on 23 spatial replicates per land use and (b) Landscape B based
on 10 spatial replicates per land use. (Natural: Natural Oak Forest; Degraded: Degraded Oak Forest; Lopped: Lopped Oak Forest; Pine: Pine Forest; Built-up: Built-
up Sites).
G. Shahabuddin, R. Goswami, M. Krishnadas et al. Global Ecology and Conservation 25 (2021) e01447
6
Landscape B: F ¼6.22, p <0.01). Our results thus show that both species number and relative abundances are driving the
observed signicant changes in species composition across all the land use categories.
Within the forested land uses, natural oak was most similar to degraded oak and least similar to pine forest, as seen by the
degree of overlap of the ellipses corresponding to each land use and the inter-centroid distances (Fig. 6a and b). This was true
for both landscapes. The most dissimilar sites were natural oak and built-up sites. Cultivated sites showed highest similarity
with built-up sites in Landscape A but were closer to pine forest in Landscape B.
The assignment of habitat preference category, i.e., oak forest specialists, forest generalists, open country species and
commensal species in the bird community is given in Appendix D. The abundance of oak forest specialists declined sharply
(by about 75%) from natural oak forest to modied land uses as seen in data from both Landscapes A and B (Fig. 7a and b).
Abundance of forest generalist species was much more constant across the land use categories in both landscapes, but
showed a steep drop in built-up sites (Fig. 7a and b). Further, open country species abundances increased along the
anthropogenic intensication gradient, with the maximum being seen in cultivation sites. There were no commensal species
in any of the four forest categories, but were reported in cultivation and built-up sites (Fig. 7a and b).
Fig. 8 shows the abundance of the three functional guilds that were compared across the six land use categories. In-
sectivores and pollinators were most abundant in natural oak forest and sharply declined in all other land use categories, by
almost 50%. Ecosystem engineers do not show a clear pattern, except that they were absent in built-up sites and showed
extremely low numbers in cultivation. In this case, abundance in pine forest was seen to be as high as in natural oak forest, but
cultivation and built-up sites showed severe depletion.
4. Discussion
Our study corroborates patterns seen in global meta-analyses: that land use change, caused by conversion of natural
forests to urban centres, monocultures, cultivation and even managed forests, adversely affects species richness, and
signicantly alters species composition. Further, both habitat preference guilds and functional guilds are adversely affected,
with the exception of ecosystem engineers, which may have been too low in numbers for a valid analysis(Gardner et al., 2009;
Sol et al., 2020). Our results thus suggest that it is as important to look at abundances of functional guilds, rather than only
species richness of avian communities in altered ecosystems, because ecosystem services depend on healthy populations of
service providers (Young et al., 2016;Maas et al., 2013;Whelan et al., 2015). Our results have signicant implications for
conservation planning in the increasingly human-dominated forest landscapes of developing countries (Sol et al., 2020;
Newbold et al., 2020).
Our NMDS results suggest signicant divergence of forested and non-forested land uses in species composition as well as
relative abundances of species. Low stress values underline the signicance of our ndings. Our results indicate that the
divergence in species composition was caused primarily bythe changes in proportion of species belonging to different habitat
preference guilds and functional guilds, as well as their abundances (Menon et al., 2019). Many of the species dropping out of
modied land uses are recognised oak forest specialists such as rufous-bellied woodpecker (Dendrocopos hyperythrus),
greater yellownape (Chrysophlegma avinucha), rufous sibia (Heterophasia capistrata), white-throated laughing thrush
(Garrulax albogularis) and black-faced warbler (Abroscopus schisticeps) (Fig. 5;Appendix D). Forest specialists are recognised
to show greater vulnerability to land use change which likely occurs due to alterations in food and nesting resources, and
competitive relationships among species comprising the regional species pool (Shochat et al., 2006;Kumar et al., 2011;
Fig. 5. Average species richness-per-site for each land use type for Landscape A (based on 23 study sites per land use) and for Landscape B (based on 10 study
sites per land use). Species richness per site is cumulative over two temporal replicates at each site. (Natural: Natural Oak Forest; Degraded: Degraded Oak Forest;
Lopped: Lopped Oak Forest; Pine: Pine Forest; Built-up: Built-up Sites).
G. Shahabuddin, R. Goswami, M. Krishnadas et al. Global Ecology and Conservation 25 (2021) e01447
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Menon et al., 2019). Forest generalists are less affected by changing land use, because they are opportunistic in using resources
from a wider range of habitat types. The much more uniform pattern of abundance in forest generalists across land use
categories (apart from built-up sites) in our own study is striking (Fig. 7a and b), and corroborates the above inference.
Alteration in species composition is also likely due to the accompanying drastic declines in abundance of pollinators and
insectivores, pointing to uneven effects of land use change on different functional guilds, a pattern that has been seen globally
as well (see Newbold et al., 2020 for a recent review).
Globally, the replacement of natural forest with monocultures of tree species has been an important cause of biodiversity
loss in different parts of the world (e.g. Srinivas and Koh, 2016;Calvino-Cancela, 2013;Mandal and Shankar-Raman, 2016). We
nd very similar patterns with respect to the chir pine forest stands in our study site, so that stands that are managed as
monocultures show poor ability to host bird species. This was found to be particularly true for forest specialists, pollinators
and insectivores. It is important to note that this nding may not be completely generalizable to all types of monocultures.
The poor species richness of birds in Himalayan chir pine stands may be ascribed to the relatively open canopy and low tree
density, as well as poor plant diversity in our study landscape. However, such features may not be reective of all other types
Fig. 6. Non-metric Dimensional Scaling (NMDS) plots showing degree of divergence in bird species composition among land use categories in (a) Landscape A
and (b) Landscape B (below). The size of each ellipse is proportional to within-group similarity of the given land use and the degree of overlap between any two
ellipses shows the degree of community similarity between the respective land uses.
G. Shahabuddin, R. Goswami, M. Krishnadas et al. Global Ecology and Conservation 25 (2021) e01447
8
of monocultures (see also Kumar et al., 2011;Menon et al., 2019). Our ndings have serious implications for Western Hi-
malayan biodiversity as both scientists and locals believe that pine stands are expanding in area at the cost of diverse
hardwood stands at middle elevations (Shahabuddin and Thadani, 2018;Naudiyal and Schmerbeck, 2017).
Cultivation sites differed substantially in composition from all the forest land uses, being most similar to built-up sites. We
found that cultivation sites provide breeding habitats for open country species such as grey bushchat, black francolin, russet
sparrow, streaked laughing thrush (Trochalopteron lineatus) and Himalayan bulbul (Pycnonotus leucogenis), which are not seen
in any forest land use. In addition, a large number of forest generalists such as blue whistling thrush and red-billed blue
magpie were also recorded in cultivation sites. However, cultivation sites are not able to support forest specialists, even whilst
providing considerable space for forest generalists, commensals and open country species (see Fig. 5a and b). Our results thus
suggest that forest species are largely not able to survive in cultivation areas, as has been seen elsewhere (Phalan et al., 2011;
Fig. 7. Abundance of the four habitat guilds of birds in each of the six land use categories in (a) Landscape A and (b) Landscape B. Natural: Natural Oak Forest;
Degraded: Degraded Oak Forest; Lopped: Lopped Oak Forest; Pine: Pine Forest; Built-up: Built-up (Urban) Sites. (OAKFOR: Oak Forest Specialists; FOREDG: Forest
generalists; COMM: Commensals; OPEN: Open Area Generalists).
G. Shahabuddin, R. Goswami, M. Krishnadas et al. Global Ecology and Conservation 25 (2021) e01447
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De Lima et al., 2013). At the same time, cultivation sites show higher species richness, as well as similar abundances of
pollinators and insectivores in comparison to the modied oak forests and pine, indicating that cultivation may help sustain
signicant ecosystem providers (although the species involved may be different). Elsen et al. (2017) found that cultivation
sites harboured a rich diversity of high-altitude species in the Western Himalaya in the winter season. Our study, however,
shows that it is essential to explore species composition as much as species richness, as our results suggest a signicantly
different avian community in cultivation in comparison to modied forests and monocultures.
Urbanization has been discussed as one of the long-term causes of species declines globally, a factor that is likely to
become more important with time (Sol et al., 2020;Carvajal-Castro et al., 2019;Shochat et al., 2006;Tiwari and Ur,2016). In
accordance with such predictions, our built-up sites were found to be the most depauperate in bird species and abundance
among all the six land uses in our study area. In the case of Landscape B, species richness was lower than that in natural oak by
almost 75%. This was true for both of our study landscapes. Further, all three functional groups were least abundant (or
absent) in this land use category, and the avifauna was dominated by open country and commensal species with very few
forest species (either specialists or generalists). Keeping in mind possible landscape effects on bird distribution that have been
Fig. 8. Abundance of functional guilds of birds compared across the six land use categories in (a) Landscape A and (b) Landscape B. Natural: Natural Oak Forest;
Degraded: Degraded Oak Forest; Lopped: Lopped Oak Forest; Pine: Pine Forest; Built-up: Built-up or Urban Sites.
G. Shahabuddin, R. Goswami, M. Krishnadas et al. Global Ecology and Conservation 25 (2021) e01447
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noted in the same landscape (see Menon et al., 2019), it is clear that growing expansion of urban and suburban land use into
natural habitats, as is happening globally, will likely lead to highly impoverished and homogeneous fauna over the long-term.
It is necessary to come up with plans to improve biodiversity values of urban habitats and reduce their impacts on adjacent
wild habitats (for example see Sol et al., 2020).
Our study also speaks to the effect of biomass extraction on avifauna, showing that lightly used forest (degraded category;
Fig. 2b) can still harbour a large proportion (50e75%) of forest species (see also Menon et al., 2019). However, if avian forest
specialists are considered, the degraded forest category harboured only 25% or less of bird abundance in comparison to
natural oak, although it had comparable overall species richness (Fig. 7a and b). Similarly, degraded forests harboured 50% or
less of pollinators and insectivores in terms of abundance (Fig. 8a and b). The above patterns in guild abundance were seen in
both Landscape A and Landscape B, suggesting that degraded forests represent only suboptimal habitat for forest specialists,
pollinators and insectivores. Yet, since degraded forests appear to provide opportunistic foraging areas for a high proportion
of forest bird species, they could possibly be used as avifaunal refugia, as long as remnants of natural forest are retained in the
landscapes to provide source populations (see also Menon et al., 2019 and Shahabuddin and Kumar, 2006). This prediction
should be tested in future studies.
Due to lack of sufcient quantitative data on forest structure, we were unable to relate the abundance of species richness
or guild abundance to specic structural or compositional changes in the used forest sites. However, the differences in
extractive activities such as leaf litter collection, and tree-lopping in the three forest categories (Appendix A) are likely to
cause signicant vegetational changes which in turn, may affect avian communities. Specically, the forest specialist, polli-
nator and insectivore guilds are likely to respond strongly to forest changes brought about by various use intensities (see
Menon et al., 2019). Our study clearly shows that degraded forests may be superior to lopped forests in their richness as well
as ability to host forest specialists, so the use intensity needs to be controlled if bird diversity is to be maintained
(Shahabuddin and Kumar, 2006). Further studies are required to better understand bird-vegetation relationships in multiple
use forests which can also lead to more focussed management recommendations.
Our study also nds that ecosystem service-providers among birds are signicantly depleted in all other land use types in
comparison to natural oak forest. Such patterns concur with those detected in global reviews of eld studies by Newbold et al.
(2020) and Sol et al. (2020) who found signicant restructuring of functional groups at large scales. It is possible that our data
on ecosystem engineers is not sufcient for discerning clear patterns as woodpeckers generally occur at low densities in
forests (see Fig. 6). Yet, our data indicates that cultivation sites and built-up sites are depleted in terms of ecosystem engi-
neers. Depletion of pollinators and insectivores can have signicant repercussions for provision of ecosystem functions in
production landscapes such as agriculture and monocultures (Sekercioglu 2006). It is necessary to carry out focussed studies
on the functioning of particular groups of ecosystem providers to study the impact on ecosystem functions in our study
landscapes (eg. Maas et al., 2013).
5. Conclusion
Our study shows that there is signicant avifaunal and guild impoverishment due to land use change from natural forests
to other forms of land use. Lightly used forests retain a large proportion of forest avifauna but urbanization, intensive use and
pine monocultures show drastic adverse effects on bird diversity and guild composition. The impact of cultivation is not so
severe in terms of species richness but it creates highlyaltered bird assemblages during breeding season. Species composition
is signicantly impacted by land use change as well, with modied oak forest categories showing much more similarity with
natural oak, than do pine, urban or cultivation sites. In terms of abundance, forest specialists, pollinators and insectivores are
affected more by land use change than other habitat guilds such as commensals, open country species and forest generalists,
which are better able to survive in modied landscapes. Such observed declines in certain functional guilds could affect bird-
provided ecosystem services both in forests and in adjoining production landscapes. Thus our results show that it may be as
important to take abundances into account, as much as species loss itself when studying patterns of defaunation (Young et al.,
2016).
A number of scholars have predicted biodiversity declines in the Himalayas due to recent developmental pressures (e.g.
Pandit et al., 2007,2014) but our study is among the few that quantify these changes based on systematic eld studies in a
diverse range of land uses (but see Srinivasan et al., 2015;Elsen et al., 2017). We recommend safeguarding of Himalayan oak
forests and their avifaunal diversity by limiting extraction of forest produce to sustainable levels, curtailing expansion of pine
monocultures, and retaining well-protected natural forest stands in the mosaic of natural and modied land uses.
Declaration of competing interest
The authors declare that they have no known competing nancial interests or personal relationships that could have
appeared to inuence the work reported in this paper.
Acknowledgements
The study was carried out using a Women Scientists research grant (WOS-A) to Ghazala Shahabuddin (SR/WOS-A/LS-150/
2014) and an SERB National Post-doctoral Fellowship to Rajkamal Goswami (2015/00107), both from Department of Scientist
G. Shahabuddin, R. Goswami, M. Krishnadas et al. Global Ecology and Conservation 25 (2021) e01447
11
and Technology, Government of India. We are grateful to Uttarakhand Forest Department for research permits and to Nar-
endra S. Raikwal, Santosh Arya and Niku Arya for assistance during the eld work.
Appendix A. Supplementary data
Supplementary data to this article can be found online at https://doi.org/10.1016/j.gecco.2020.e01447.
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... For example, the Himalaya is a home to 987 bird species out of which 43 are restricted range and 56 threatened species (Acharya et al., 2024). However, the biodiversity of the Himalaya, including bird community, is under constant threat due to loss of current and potential suitable habitats primarily as a result of forest degradation (Pandit et al., 2007;Acharya & Vijayan, 2017;Shahabuddin et al., 2021). Various anthropogenic activities such as unsustainable development and deforestation have severely impacted avian biodiversity of the Himalayan region (Bushra et al., 2021;Putri et al., 2020;Shahabuddin et al., 2021). ...
... However, the biodiversity of the Himalaya, including bird community, is under constant threat due to loss of current and potential suitable habitats primarily as a result of forest degradation (Pandit et al., 2007;Acharya & Vijayan, 2017;Shahabuddin et al., 2021). Various anthropogenic activities such as unsustainable development and deforestation have severely impacted avian biodiversity of the Himalayan region (Bushra et al., 2021;Putri et al., 2020;Shahabuddin et al., 2021). Moreover, the rapid changes in the climate due to global warming have caused disruption in phenology of Himalayan avifauna leading to high extinction risks (Both et al., 2006;Acharya et al., 2011a;Acharya & Chettri, 2012;Paudel & Sipos, 2014). ...
... During the breeding season, competition for mates and nesting sites becomes intense, leading to more pronounced differences in community composition as birds align their reproductive efforts with the optimal environmental conditions for raising young ones. Certain species may preferentially select habitats that provide the necessary conditions for successful breeding, resulting in significant differences between agropastoral and forest areas during these seasons (Varun & Dutta, 2020;Shahabuddin et al., 2021). ...
Article
The ever-increasing demand for agricultural products due to global human explosion has resulted into deforestation and forest fragmentation leading to biodiversity loss. These paradigms have urged to identify and adopt agroforestry practices that uphold and restore biodiversity. The high elevation traditional agropastoral system prevalent in the Himalaya is one among such practices, but biodiversity wealth and ecosystem functioning of this system are not understood properly. Here, we have undertaken a study to understand the potentiality of multifunctional agropastoral mosaics located in Sikkim, Eastern Himalaya, India, in retention and conservation of temperate avifauna. We used point count method along set transects spread across five study sites spanning elevation range of 2300–3700 m to sample birds. We observed 88 bird species during the study among which 56 species including four Eurasian high montane biome species and seven Sino-Himalayan temperate forest biome species were observed in agropastoral system. Similarly, the community composition between the agropastoral system and nearby forest ecosystem (taken as control sites) differed significantly between the systems indicating the high conservation significance of agropastoral landscape mosaics for high elevation birds. Species richness and density of birds grouped into different functional categories were equivalent (or even higher in agropastoral) in both systems across the seasons. We found that these birds provide potential ecosystem services such as pest control, seed dispersal, nutrient decomposition, waste disposal, and pollination. Our results suggest that the agropastoral mosaics reflecting high habitat heterogeneity complement natural forest in retention and conservation of high elevation birds in the Himalaya. Hence, appropriate conservation measures must be undertaken to safeguard this unique multifunctional ecosystem and its avifaunal diversity.
... The region is also a center of species radiation; for example, out of 52 species of pheasants found in the world, 16 species occur in the Himalaya (del Hoyo et al., 1994). Ironically, the unsustainable developmental activities and tourism enterprises are at constant rise in the region (Laiolo, 2004;Acharya et al., 2010;Baral et al., 2012;Pandit and Grumbine, 2012;Grumbine and Apple Academic Press Author Copy Pandit, 2013) and studies have found negative responses of birds to such activities (Chettri et al., 2001;Laiolo, 2004;Putri et al., 2020;Bushra et al., 2021;Shahabuddin et al., 2021). Similarly, Himalayan biodiversity including avifauna are facing a great threat, mostly due to forest degradation leading to loss of existing and potential habitats Shahabuddin et al., 2021). ...
... Ironically, the unsustainable developmental activities and tourism enterprises are at constant rise in the region (Laiolo, 2004;Acharya et al., 2010;Baral et al., 2012;Pandit and Grumbine, 2012;Grumbine and Apple Academic Press Author Copy Pandit, 2013) and studies have found negative responses of birds to such activities (Chettri et al., 2001;Laiolo, 2004;Putri et al., 2020;Bushra et al., 2021;Shahabuddin et al., 2021). Similarly, Himalayan biodiversity including avifauna are facing a great threat, mostly due to forest degradation leading to loss of existing and potential habitats Shahabuddin et al., 2021). ...
... Moreover, majority of the rural population of the Himalayan region still depends upon primary forest for fodder, timber, fuelwood, etc. Such reliance on forests resulting into constant alteration and degradation of habitats have greatly affected the avian community especially forest specialists, pollinators, and insectivorous species along with other faunal components (Gupta et al., 2019;Menon et al., 2019;Shahabuddin et al., 2021). In order to minimize the human interference and conserve the habitats and associated biodiversity, including birds, several initiatives have been taken at the national and international level. ...
... The region is also a center of species radiation; for example, out of 52 species of pheasants found in the world, 16 species occur in the Himalaya (del Hoyo et al., 1994). Ironically, the unsustainable developmental activities and tourism enterprises are at constant rise in the region (Laiolo, 2004;Acharya et al., 2010;Baral et al., 2012;Pandit and Grumbine, 2012;Grumbine and Pandit, 2013) and studies have found negative responses of birds to such activities (Chettri et al., 2001;Laiolo, 2004;Putri et al., 2020;Bushra et al., 2021;Shahabuddin et al., 2021). Similarly, Himalayan biodiversity including avifauna are facing a great threat, mostly due to forest degradation leading to loss of existing and potential habitats (Pandit et al., 2007;Shahabuddin et al., 2021). ...
... Ironically, the unsustainable developmental activities and tourism enterprises are at constant rise in the region (Laiolo, 2004;Acharya et al., 2010;Baral et al., 2012;Pandit and Grumbine, 2012;Grumbine and Pandit, 2013) and studies have found negative responses of birds to such activities (Chettri et al., 2001;Laiolo, 2004;Putri et al., 2020;Bushra et al., 2021;Shahabuddin et al., 2021). Similarly, Himalayan biodiversity including avifauna are facing a great threat, mostly due to forest degradation leading to loss of existing and potential habitats (Pandit et al., 2007;Shahabuddin et al., 2021). ...
... Avifauna in the Himalaya are at risk due to various anthropogenic activities such as deforestation, agricultural intensification, hunting and trapping, etc. (Islam, 2008;Shahabuddin et al., 2021). Moreover, majority of the rural population of the Himalayan region still depends upon primary forest for fodder, timber, fuelwood, etc. ...
Chapter
Himalaya represents a unique landscape displaying varied eco-zones, climatic conditions, large elevation gradient, and enormous natural resources. Among the range of biodiversity, birds are well studied in the Himalaya but findings of research and exploration in the region has not been systematically compiled till date. In this chapter, we provide a detailed account of avifaunal wealth of the Himalaya covering species occurrence, elevation distribution range of each species (wherever available), IUCN threat category, range restricted status, migratory status, population trend, and habitat utilization of Himalayan birds. Based on the review of existing research articles, reference books, and authentic web sources supplemented by our own observations, we have developed a comprehensive database of birds covering all Himalayan states (erstwhile undivided Jammu & Kashmir, Himachal Pradesh, Uttarakhand, Sikkim, Darjeeling, and Kalimpong districts of West Bengal and Arunachal Pradesh) along with neighboring countries Nepal and Bhutan. We also assessed whether the existing protected areas in the region are in congruence with the diversity of birds. We reviewed 1901 literatures and observed that ornithological exploration was initiated in the region in 17th century with rapid pace of research since 1990 reflecting the maximum number of publications (344) in the last decade (2011–2020). The database of birds with reported and potential distribution in the Himalaya comprises 987 species and 385 genera representing 99 avian families. Similarly, out of the total bird species, 180 (18.2%) are water birds and 807 (81.8%) terrestrial species representing ~39% forest specialist, ~30% forest generalist, ~8.2% high altitude birds, and 3.5% open land species. Based on migratory status, 428 species are full migrants followed by 416 resident and 140 altitudinal migrant species. Among the total, IUCN has enlisted 881 species as Least Concerned, whereas 56 species are listed as threatened with extinction (vulnerable 33, endangered 12 and critically endangered 11) along with 49 near-threatened species. We observed a clear mis-match between the elevational distribution of protected areas (along with area coverage) and avian diversity showing maximum area coverage by PAs between 4000 and 5000 m elevation but maximum bird diversity at middle elevation gradient (~2000 m). We also noted the existence of 122 PAs in the region along with 165 notified Important Bird Areas and 19 designated Ramsar sites. We conclude that along with these legally protected conservation sites, human-modified areas (including agricultural lands) outside PAs are important for avian conservation and requires policy intervention.
... This makes them excellent flagship species for wetland productivity. 45 Wetlands that large waterbirds use are complex ecosystems that serve a number of human purposes. These include the provisioning of water for irrigation and drinking, transportation, fishing, livestock grazing, and generally providing a public space for recreation and nature appreciation. ...
... Apart from species loss, the kinds of species that persist in plantations are often very different from those in adjoining forests. In the Himalaya, horticultural landscapes have only 15% fewer bird species than those in natural forest, but these are a radically different set of species, dominated by open area generalists and forest edge species 45 ...
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The chapter discusses some of the major known human-caused threats to birds. - Long term trends in bird species
... Many other scholars (e.g., Addae & Oppelt, 2019;Anarfi et al., 2020;Martellozzo et al., 2015;Ziaul Hoque et al., 2022) have used remote sensing technologies to estimate the size and extent of the ESAs degradation resulting from the expansion of cities. Some of the studies have provided evidence of shrinking wetlands, deforestation, declining vegetation cover, and growing natural area fragmentation (Basu et al., 2023;Sandhya Kiran & Joshi, 2013;Shahabuddin et al., 2021;Ziaul Hoque et al., 2022). Others have highlighted the utility of ESAs, particularly for mitigating greenhouse gases, providing food and medicine as well as for flood mitigation purposes (Ahmad et al., 2019;Darkwah & Cobbinah, 2014;Johnston & McIntyre, 2019;Leman et al., 2016;McWilliam et al., 2015). ...
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Ecologically sensitive areas (ESAs) support the sustainability of cities worldwide. Nevertheless, their encroachment by grey land uses in cities, particularly in sub-Saharan Africa (SSA), has led to their sturdy deterioration. The current study assessed encroachers' appreciation of the utility of ESAs towards unpacking their motivation to encroach on these spaces. This has received limited scholarly attention. The study empirically focused on Kumasi, a rapidly urbanising city in Ghana, and adopted the convergent parallel mixed-method design to gather and analyse data. The results indicate that the encroachment phenomenon is not monolithic. Generally, en-croachers were more aware of ESAs' provisioning and cultural functions than their regulating and ecosystem services. The results further revealed that urbanisation, the dual system of urban land management, and in-dividuals' ignorance of the importance of ESAs were the main factors that contributed to the overall depletion of ESAs. The study found evidence of both 'bold' and 'quiet' encroachment where, on the one hand, some actors (particularly property developers) courageously encroached and consolidated their gains via political maneuvers , while on the other hand, 'ordinary' individuals incrementally and silently encroached due to limited housing and economical options. The paper concludes by recommending that policies and regulations designed to manage ESAs should move away from a brutal and violent enforcement approach to critically consider the perspective of encroachers. One critical strategy is to educate encroachers to enhance both their awareness and knowledge of the importance of ESAs.
... Over 1300 species of mammals, 2100 species of birds, and 3300 species of amphibians are restricted to mountain ranges (Rahbek et al. 2019), yet many mountain species are under threat from anthropogenic stressors. Among these, land use change and tourism can cause reduction in species diversity and gene flow (Rolando et al. 2007;Robin et al. 2015;Shahabuddin et al. 2021). Mountain wetlands are being increasingly contaminated by inorganic and organic pollutants (Schmeller et al. 2022) while invasive species are altering the habitat and resources available to native fauna (Sharma et al. 2021a). ...
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Mountains harbour one third of the world’s biodiversity and much of it is under increasing anthropogenic pressure. Yet, global assessments of the occurrence, and threat status of most mountain taxa, especially elusive ones are lacking, thereby hindering conservation and research prioritisation. In this study, we synthesise the distribution and conservation status of bats, a species rich taxon on mountains. By using data on geographical and elevational distribution ranges from the International Union for Conservation of Nature (IUCN), we examined bat species richness on mountains, species that predominantly occur in mountains (‘mountain dwelling species’), and those restricted to upper montane and alpine regions within mountains (‘highland dwelling species’). We also used published trait datasets to investigate the traits that are associated with mountain dwelling in bats. Globally, we identified 148 mountain dwelling and 46 highland dwelling bat species. Bat diversity is highest in the Northern Andes and Guiana Highlands. The mountain dwelling nature of bat species was found to be significantly associated with biogeographic realm. Importantly, our results show that mountain dwelling species are proportionately more data deficient than species that predominantly occur in lowlands. Additionally, highland dwelling species are proportionately more threatened than lowland species. Our results highlight a significant dearth of knowledge on mountain dwelling bat species. We conclude that more research is needed for bats specialised on mountain ecosystems. Our results draw attention towards improving the knowledge and protection of bat species that occur predominantly at high elevations across the world.
... As extinction rates amongst rare, specialized, and large-bodied species of tropical forest-dwelling birds are disproportionately high, mesopredator release may be a causal link between similar declines in tropical apex predators and a reduction in terrestrial forestdwelling birds [15][16][17][18]. The loss of birds is of concern as their decline can have various impacts on ecosystem services including changes to seed dispersal, pollination, carrion consumption, nutrient cycling, and populations of invertebrates or vertebrates, of which some are relevant as pests [19]. ...
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Amongst the unintended consequences of anthropogenic landscape conversion is declining apex predator abundance linked to loss of forest integrity, which can potentially re-order trophic networks. One such re-ordering, known as mesopredator release, occurs when medium-sized predators, also called mesopredators, rapidly increase in abundance following the decline in apex predator abundance, consequently reducing the abundance of mesopredator prey, notably including terrestrial avifauna. We examine the cascading impacts of declining Sunda clouded leopard abundance, itself consequent upon a reduction in forest integrity, on the mesopredator community of Sabah, Malaysia, to determine whether the phenomenon of mesopredator release is manifest and specifically whether it impacts the terrestrial avifauna community of pheasants and pittas. To explore this trophic interaction, we used a piecewise structural equation model to compare changes in the relative abundance of organisms. Our results suggest that loss of forest integrity may have broad impacts on the community and trigger mesopredator release, the two acting additively in their impact on already vulnerable species of terrestrial avifauna: a result not previously documented in tropical systems and rarely detected even on a global scale. The limiting effect that the Sunda clouded leopard has on the Sunda leopard cat could illuminate the mechanism whereby mesopredator release impacts this system. Both Bulwer's pheasant and pittas appear to be significantly impacted by the increase in Sunda leopard cats, while the great argus pheasant shows similar compelling, although not statistically significant, declines as Sunda leopard cats increase. The inverse relationship between Sunda clouded leopards and Sunda leopard cats suggests that if a mesopredator release exists it could have downstream consequences for some terrestrial avifauna. These results suggest the under-studied interface between mammalian carnivores and avifauna, or more broadly species interactions in general, could offer important conservation tool for holistic ecosystem conservation efforts.
Technical Report
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This report represents a critical assessment, the first in almost 15 years (since the release of the Millennium Ecosystem Assessment in 2005) and the first ever carried out by an intergovernmental body, of the status and trends of the natural world, the social implications of these trends, their direct and indirect causes, and, importantly, the actions that can still be taken to ensure a better future for all. These complex links have been assessed using a simple, yet very inclusive framework that should resonate with a wide range of stakeholders, since it recognizes diverse world views, values and knowledge systems. This report is one of the outputs of the Global Assessment of Biodiversity and Ecosystem Services. This Assessment was carried out by about 150 selected experts from all regions of the world, including 16 early career fellows, assisted by 350 contributing authors. More than 15,000 scientific publications were analyzed as well as a substantive body of indigenous and local knowledge. Its chapters were accepted, and its summary for policymakers was approved, by the more than 130 Governments that constitute the Members of IPBES, at the seventh session of the IPBES Plenary (29th April to 4th May, 2019), hosted by France at UNESCO in Paris.
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Urbanisation is driving rapid declines in species richness and abundance worldwide, but the general implications for ecosystem function and services remain poorly understood. Here, we integrate global data on bird communities with comprehensive information on traits associated with ecological processes to show that assemblages in highly urbanised environments have substantially different functional composition and 20% less functional diversity on average than surrounding natural habitats. These changes occur without significant decreases in functional dissimilarity between species; instead, they are caused by a decrease in species richness and abundance evenness, leading to declines in functional redundancy. The reconfiguration and decline of native functional diversity in cities are not compensated by the presence of exotic species but are less severe under moderate levels of urbanisation. Thus, urbanisation has substantial negative impacts on functional diversity, potentially resulting in impaired provision of ecosystem services, but these impacts can be reduced by less intensive urbanisation practices.
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Human land use has caused substantial declines in global species richness. Evidence from different taxonomic groups and geographic regions suggests that land use does not equally impact all organisms within terrestrial ecological communities, and that different functional groups of species may respond differently. In particular, we expect large carnivores to decline more in disturbed land uses than other animal groups. We present the first global synthesis of responses to land use across functional groups using data from a wide set of animal species, including herbivores, omnivores, carnivores, fungivores and detritivores; and ranging in body mass from 2 × 10⁻⁶ g (an oribatid mite) to 3,825 kg (the African elephant). We show that the abundance of large endotherms, small ectotherms, carnivores and fungivores (although in the last case, not significantly) are reduced disproportionately in human land uses compared with the abundance of other functional groups. The results, suggesting that certain functional groups are consistently favoured over others in land used by humans, imply a substantial restructuring of ecological communities. Given that different functional groups make unique contributions to ecological processes, it is likely that there will be substantial impacts on the functioning of ecosystems. A free Plain Language Summary can be found within the Supporting Information of this article.
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India has the second largest population in the world and is characterized by a broad diversity in climate, topography, flora, fauna, land use, and socioeconomic conditions. To help ensure food security in the future, agricultural systems will have to respond to global change drivers such as population growth, changing dietary habits, and climate change. However, alterations of how food is produced in the future may conflict with other UN Sustainable Development Goals (SDGs), such as the protection of land resources and climate change mitigation. It is crucial for decision‐makers to understand potential trade‐offs between these goals to find a balance of human needs and environmental impacts. In this paper, we analyze pathways of agricultural productivity, land use, and land‐cover changes in India until 2030 and their impacts on terrestrial biodiversity and carbon storage. The results show that in order to meet future food production demands, agricultural lands are likely to expand, and existing farmlands need to be intensified. However, both processes will result in biodiversity losses. At the same time, the projections reveal carbon stock increases due to intensification processes and decreases due to conversions of natural land into agriculture. On balance, we find that carbon stocks increase with the scenarios of future agricultural productivity as modeled here. In conclusion, we regard further agricultural intensification as a crucial element to help ensure food security and to slow down the expansion of cropland and pasture. At the same time, policies are required to implement this intensification in a way that minimizes biodiversity losses.
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Urbanization is currently one the most important causes of biodiversity loss. The Colombian Andes is a well-known hotspot for biodiversity, however, it also exhibit high levels of urbanization , making it a useful site to document how species assemblages respond to habitat transformation. To do this, we compared the structure and composition of bird assemblages between rural and urban habitats in Armenia, a medium sized city located in the Central Andes of Colombia. In addition, we examined the influence of urban characteristics on bird species diversity within the city of Armenia. From September 2016 to February 2017 we performed avian surveys in 76 cells (250 x 250 m each) embedded within Armenia city limits; and in 23 cells (250 x 250 m each) in rural areas around Armenia. We found that bird diversity was significantly lower in urban habitats than in rural habitats, and differed in species composition by 29%. In urban cells, with higher abiotic noise intensity and higher impervious surface area, we found lower bird diversity than that in urban cells with higher guadual (Gua-dua angustifolia patches), and forested surface areas. We did not find segregation of urban cells according to the species composition, although additional bird surveys inside urban forests remnant are needed to be more conclusive about this aspect. Altogether, our results highlight the importance of green areas embedded within cities to conserve bird diversity through reducing the ecological impact of urbanization on avian biodiversity.
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Urbanization is currently one the most important causes of biodiversity loss. The Colombian Andes is a well-known hotspot for biodiversity, however, it also exhibit high levels of urbanization, making it a useful site to document how species assemblages respond to habitat transformation. To do this, we compared the structure and composition of bird assemblages between rural and urban habitats in Armenia, a medium sized city located in the Central Andes of Colombia. In addition, we examined the influence of urban characteristics on bird species diversity within the city of Armenia. From September 2016 to February 2017 we performed avian surveys in 76 cells (250 x 250 m each) embedded within Armenia city limits; and in 23 cells (250 x 250 m each) in rural areas around Armenia. We found that bird diversity was significantly lower in urban habitats than in rural habitats, and differed in species composition by 29%. In urban cells, with higher abiotic noise intensity and higher impervious surface area, we found lower bird diversity than that in urban cells with higher guadual (Guadua angustifolia patches), and forested surface areas. We did not find segregation of urban cells according to the species composition, although additional bird surveys inside urban forests remnant are needed to be more conclusive about this aspect. Altogether, our results highlight the importance of green areas embedded within cities to conserve bird diversity through reducing the ecological impact of urbanization on avian biodiversity.
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Rapid urbanization has become an area of crucial concern in conservation owing to the radical changes in habitat structure and loss of species engendered by urban and suburban development. Here, we draw on recent mechanistic ecological studies to argue that, in addition to altered habitat structure, three major processes contribute to the patterns of reduced species diversity and elevated abundance of many species in urban environments. These activities, in turn, lead to changes in animal behavior, morphology and genetics, as well as in selection pressures on animals and plants. Thus, the key to understanding urban patterns is to balance studying processes at the individual level with an integrated examination of environmental forces at the ecosystem scale.
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Although there is a diversity of concerns about recent persistent declines in the abundances of many species, the implications for the associated delivery of ecosystem services to people are surprisingly poorly understood. In principle, there are a broad range of potential functional relationships between the abundance of a species or group of species and the magnitude of ecosystem-service provision. Here, we identify the forms these relationships are most likely to take. Focusing on the case of birds, we review the empirical evidence for these functional relationships, with examples of supporting, regulating, and cultural services. Positive relationships between abundance and ecosystem-service provision are the norm (although seldom linear), we found no evidence for hump-shaped relationships, and negative ones were limited to cultural services that value rarity. Given the magnitude of abundance declines among many previously common species, it is likely that there have been substantial losses of ecosystem services, providing important implications for the identification of potential tipping points in relation to defaunation resilience, biodiversity conservation, and human well-being.