Dry tropical forests are the most threatened tropical biome. Restoring them on islands is essential for supporting ecosystem functions of interconnected terrestrial and marine ecosystems. Identifying the best strategies to stimulate dry forest recovery is urgently needed. We analysed passive and active restoration approaches conducted at different spatial and temporal scales within the same study system on the Caribbean island of Bonaire: (1) natural regeneration in experimental plots (n = 14 paired fenced-unfenced plots, 9 & times; 9 m each, 15 years), (2) natural regeneration after removal of feral herbivores at landscape scales (n = 24 plots, 10 & times; 10 m each, 4 years), (3) enrichment planting of seedlings under fenced remnant forest patches (7655 seedlings, 43 tree species, 8 reforestation sites; 100 & times; 100 m ha each). We monitored tree establishment, taxonomical and functional diversity, soil hydrology and fertility. We subsequently reflected on the participatory experiences that facilitated dry forest restoration. Tree seedling establishment increased when herbivores were excluded or their densities drastically reduced, especially during favourable climatic windows associated with rainy years. However, significant increases in the abundance of saplings and trees required up to 15 years of herbivore exclusion. Only one third of the dry forest tree species recruits naturally with slow shifts from conservative to acquisitive functional trait strategies as forest succession progresses without herbivores. Herbivore exclusion results in higher litter accumulation and lower amounts of organic matter in runoff, but no significant differences in soil nutrients, water runoff or infiltration capacity after 9 years. Planted seedlings in fenced remnant forest patches show high survival rates across species and sites. Synthesis and applications. Slow recovery of degraded Caribbean dry tropical forests can be accelerated by combining herbivore removal at landscape scales with enrichment planting of rare tree species under the cover of remnant forest patches. Long-legacy effects on soils and forest taxonomical and functional diversity require long-term management and community engagement.

Among Iguaninae species, Iguana iguana (Linnaeus) has the largest geographic range, spanning most of the Neotropical mainland and numerous islands including several in the Lesser Antilles. Genetic data indicated the presence of cryptic diversity and at least four major, mtDNA clades. However, rather than assessing the taxonomic status of these four major clades, recent taxonomic work has focused more narrowly on populations in the Lesser Antilles nested deeply within one major clade. In one such case, melanistic populations on Saba, Montserrat, and in northern Venezuela have been proposed as Iguana melanoderma Breuil et al. Here we re-evaluate the taxonomic status of I. melanoderma within the broader context of the I. iguana species complex. We generated museomic data from 10 specimens collected as early as 1929 from 10 new localities across northern Venezuela, and two samples from Trinidad, resulting in eight previously unknown ND4 haplotypes. We conducted divergence comparisons and phylogenetic analyses using mtDNA sequences. Our results indicate that the previously reported genetic distinctiveness of I. melanoderma was over-estimated due to limited geographic sampling. Instead, genetic data from northern South America reveal an eroded distinction and shallow divergences among sampled populations of the I. iguana species complex (Clade IV), including the proposed Iguana melanoderma. Numerous sampling gaps remain in this region of northern South America, which hamper taxonomic interpretations of current genetic data. Beyond genetics, the morphological dataset underlying the description of I. melanoderma was geographically limited and lacked data from crucial populations. We argue that, for the present, I. melanoderma should not be recognized but instead should be considered part of I. iguana (Clade IV), and we highlight the importance of broader sampling efforts in future taxonomic research on this species complex as well as the necessity of considering range-wide variation in taxonomic studies of wide-ranging taxa more generally.

Reptiles have among the highest extinction risk across terrestrial vertebrates, with habitat fragmentation, habitat destruction, and invasive alien species being the primary causes of reptile species loss on a global scale. Invasive hybridization (i.e. hybridization between native and invasive alien species) is increasing globally, causing the extinction of native genotypes, and this phenomenon is particularly pervasive in Caribbean iguanas. The Lesser Antillean Iguana (Iguana delicatissima), a keystone species of Caribbean coastal ecosystems, has become critically endangered mainly due to ongoing hybridization with the invasive Common Green Iguana (I. iguana). For impactful conservation intervention, the need for early detection of invasive animals and their progeny, or detection of surviving pure native animals, is urgent. We aimed to develop a novel environmental DNA (eDNA) toolkit using Kompetitive Allele Specific PCR (KASP) technology, a method of allele-specific amplification for cost-effective and efficient sampling of terrestrial substrates to aid in mapping the distribution of native I. delicatissima, invasive I. iguana, and signal potential invasive hybridization. We demonstrate proof-of-concept and successfully identified I. delicatissima, I. iguana, and their hybrids via blood samples using our primer sets, as well as successful detection of I. delicatissima in several ex-situ (Rotterdam Zoo) and in-situ (St. Eustatius) eDNA samples, collected with environmental swabs and tape-lifting. We found that sampling potential perching spots yielded the highest number of positive detections via environmental swabbing and tape-lifting. Our toolkit demonstrates the potential of terrestrial eDNA sampling for iguana conservation, enabling faster detection of putative invasive hybridization. Additionally, the method holds promise for other terrestrial cryptic species, contributing to broader collection of population-level information.

Hybridization is among the main threats posed by invasive alien species (IAS) and can lead to extinction of endangered species. Here we focus on insular native populations of Iguana in the Lesser Antilles that are threatened by hybridization with non-native green iguanas (NNGI) through genetic swamping and eventual extinction. Whilst much effort is put towards preventing NNGI incursions and these subsequent processes, their underlying mechanims are poorly understood. We collected data on snout-vent length (SVL), tail length (TL) and clutch size during an eradication program of hybrid and non-native iguanas on the island of Saba. First, we genetically assessed the status (native/hybrid/non-native) of all individuals from Saba. Subsequently, we combined these data with total length (SVL+TL) data from NNGI on St. Martin (source of NNGI on Saba), and SVL and clutch size from native insular and mainland Iguana populations. We found that hybrids on Saba produce significantly larger clutches than native Saba iguanas with a similar SVL, and even larger than one mainland population. However, comparisons of total length between native and hybrid Saba iguanas and NNGI from St. Martin indicate that native iguanas are only significantly smaller than NNGI, not compared to hybrids. Our results suggest that declines in native Iguana populations are at least partially driven by genetic swamping, through larger clutch sizes of NNGI as well as larger clutch sizes of hybrid iguanas compared to native iguanas. To optimize long-term conservation maintaining intraspecific genetic diversity is critical and we thus urge rapid identification and protection of remaining native iguanas within populations heavily impacted by hybridization with NNGI (e.g., Grenada, Guadeloupe, and Martinique). ### Competing Interest Statement The authors have declared no competing interest. Dutch Iguana Foundation Iguanaland Conservation Fund Public Entity Saba within their invasive species project Dutch Ministry of Agriculture, Fisheries, Food Security and Nature

We compiled, collated, and annotated 1033 dugong records for the Indonesian archipelago for the period 2010-2022. The database comprises 337 incidental reports documented via various media sources and 696 cases based on publications and gray literature. Four of six apparent dugong hotspot areas were clustered around small archipelagos of the Banda Sea. Two others were clustered roughly 1000 km away around archipelagos at the opposite end of the Java Sea. Both Indonesian hotspot clusters were adjacent to recognized dugong hotspots located outside Indonesian waters. Notwithstanding known seagrass-dependency, documented dugong records were not significantly correlated with seagrass abundance. Seagrass was most prevalent around small sparsely populated offshore archipelagos, where riverine freshwater and sedimentation were also less. Notwithstanding seagrass presence along the west coast of Sumatra, the area had limited connectivity to other dugong hotspots and was largely devoid of dugong records. Dugong size-structure data were bimodal and dominated by larger animals, suggesting either recent immigration or recent local decline in reproductive success. Most documented mortality records were on the north-west side of the Java Sea and mainly due to entanglement bycatch. Citizen science, gray literature, and social media data have clear added value but the need for more quantitative, standardized, and reliable data are emphasized.

The Indonesian coastline holds significant potential for aquaculture but is increasingly vulnerable to climate change impacts such as land subsidence, salinization, and floodings. Ensuring stable income for local communities is essential, especially during extreme events like King Tides, which cause extensive floodings. This study assessed the productivity and economic returns of an agaroid seaweed monoculture compared to co-cultivation with Giant tiger prawn, Milkfish, and Barramundi during a King Tide. The experiment was conducted in conventional ponds with seaweed monoculture or combined with one of the three other commodities. The experiment ran from May until October in 2022 and was performed in triplicate. Floodings equalized water parameters. The results demonstrated that all systems provided stable income, with co-cultivation increasing profitability. Average revenues per hectare were USD 777 (seaweed monoculture), USD 832 (with shrimp), USD 1622 (with Milkfish), and USD 2014 (with Barramundi). Agar content was significantly higher in the seaweed monoculture, and gel strength was found to be significantly higher in the seaweeds co-cultivated with shrimp and Milkfish. Total agar production did not differ between the treatments. These findings suggest that integrated aquaculture systems can enhance income resilience while supporting food security in climate-impacted coastal zones. The approach offers a promising strategy for combining livelihood stability with adaptive coastal management and reduced environmental impact but needs to be tailored to local conditions.

Conservation management of natural populations is ideally based on the most accurate data of critical variables including demography, natural history and population size. Although Caribbean iguanids are highly threatened by a range of anthropogenic threats, the native melanistic Iguana iguana populations in the Lesser Antilles have received surprisingly little research attention. Here we assessed population size, distribution and degree of melanism for the melanistic iguanas of Saba, Caribbean Netherlands based on one month of fieldwork. Distance sampling (based on 117 separate surveys along 38 unique transects, totalling 48 survey hrs) estimated the island population size at 8233 +/- 2205 (SD) iguanas. Female maximum snout-vent length (39.0 cm) of 56 captured iguanas was less than that of males (43.9 cm). Iguanas mainly occurred on the southern and eastern sides of the island, at mid-altitudes between 180 and 390 m (max 530 m), with highest densities being in residential and certain natural areas. Historically, iguanas have been reported from higher altitudes, where their presence was likely facilitated by former extensive forest clearing for agricultural reasons. Contrary to earlier statements claiming that 20% of adult males were fully melanistic, we found that only 1% of adult iguanas exhibited > 90% melanism, whereas 81% of males were less than 50% melanistic on the body. No relationship was found between the degree of melanism and elevation, which has been suggested by others. Probably, one main threat to the Saba green iguana population is the documented crossbreeding with non-native green iguanas. Beyond non-native iguanas, the long-term stability of the native population appears under pressure given the limited nesting sites and extremely low presence of juvenile and hatchling iguanas (2.4%). In particular, the island's feral cat and large goat population likely impact nest-site quality, nest success and hatchling survival.

A significant body of controlled laboratory research suggests different biological mechanisms by which the low-cost co-culture of seaweed and shrimp could improve sustainability whilst increasing income for the many poor pond farmers of South-East Asia. However, at the pond level, production and cost–benefit assessments remain largely lacking. Here, we studied the extensive co-culture of Gracilariopsis longissima seaweed and Penaeus monodon shrimp on pond production output, nutrient concentrations, and farm income on the north coast of Java, Indonesia. Co-culture showed 18% higher seaweed production during the first cycle (2261.0 ± 348.0 kg·ha−1) and 27% higher production during the second (2,361.0 ± 127.3 kg·ha−1) compared to monoculture. Shrimp production per cycle was 53.8% higher in co-culture (264.4 ± 47.6 kg·ha−1) than in single-species cultivation (171.7 ± 10.4 kg·ha−1). Seaweed agar content and gel strength did not differ between treatments, and neither did shrimp bacterial or heavy metals concentrations. The profit of co-culture was, respectively, 156% and 318% compared to single-species seaweed and shrimp cultivation. Co-cultivation lowered nutrient loading in the pond water and in the sediment and is argued to be a low-investment and environmentally friendly option for poor pond farmers to improve their income and financial resilience through product diversification.

Vegetation on islands is particularly vulnerable to overgrazing by introduced herbivores as plants have evolved under lower herbivore pressure than on the mainland. We conducted a combination of field experiments and surveys to study the foraging behavior of feral goats and their impact on the composition, abundance and condition of keystone columnar cactus species. On the goat-browsed Caribbean island of Bonaire, 76.6 % of the adult cacti showed bark damage. The degree of bark damage on individual cacti was negatively correlated with the probability of bearing fruits and the number of fruits carried. Foraging experiments, in both field and enclosure settings, showed that goats preferentially consume the Subpilocereus repandus cacti. Experimental spine removal did not change goat foraging preference for this species. Overgrazing by feral goats reduced recruitment and increased mortality, shifting species relative abundance and population structure of columnar cacti species. S. repandus had a population structure characterized by a large proportion of adults, and low proportion of juveniles and resprouting individuals. We subsequently show that cactus communities have largely recovered from such impacts on the nearby island of Klein Bonaire where goats have been controlled for about half a century. Our findings reveal how overgrazing by feral goats shapes the community structure of columnar cactus species and imply that goat eradication is an essential step for the recovery and conservation of the original columnar cacti communities of Caribbean dry seasonal forests.

Mangrove ecosystems support a diverse array of animal species and also provide pivotal ecosystem services, such as coastal protection, food provisioning, and carbon capture. However, these vital habitats are in decline, leading to coastal degradation in many parts of the globe. To address this, a mangrove restoration project in Demak, Java, Indonesia, introduced the use of semi-permeable coastal protective barriers made of bamboo pilings to safeguard the shore zone and hinterlands. The introduction of such hard substrate in the marine environment can attract a range of species, and it is important to be able to monitor changes in biodiversity from a restoration point of view. Here, we assessed whether environmental DNA metabarcoding can be applied to monitor fish biodiversity in an understudied area. Our results show slight but significant differences in species richness and fish community composition within a short timeframe of only 4 months, although we cannot disentangle the effects of seasonal variation from those of the introduction of hard substrate. More importantly, this study demonstrates a useful level of temporal resolution of eDNA metabarcoding and establishes a baseline for fish species richness in an understudied mangrove coastal zone in Demak, Java, Indonesia. Our results are of value for informing future restoration efforts and other (metabarcoding) biodiversity studies in the region.

Island systems provide unique opportunities to explore the genomic basis of species diversification and novel trait evolution driven by adaptation to environmental challenges and exploitation of new ecological niches. Here we generate the first genomic sequences for the four Galápagos iguana species to show that they evolved in situ into the marine Amblyrhynchus and land Conolophus sister lineages on now submerged islands, following a single colonisation event approximately 13 million years ago, with evidence for recent inbreeding coincident with the timing of human settlement. Selection scans identified genes linked to traits facilitating adaption to the Galápagos environment, including specialised pigmentation phenotypes, as well as DNA damage and UV irradiation inflammation responses. These may contribute to adaptive enhanced cancer resistance, in relation to elevated UV exposure at equatorial latitudes. In the marine iguana, genes under positive selection are associated with their transition to underwater foraging, as well as their unique ability to repeatedly shrink and grow in body size. Our study provides insights into the origins and diversification of the iguanas and the molecular basis of adaptation to life in the Galápagos, facilitating future conservation genomic management of threatened iguanid populations. ### Competing Interest Statement The authors have declared no competing interest.

Following centuries of persecution and the destruction and degradation of wetland habitat, the coastal populations of the American crocodile, Crocodylus acutus, of Colombia and Venezuela show signs of recovery, in part, due to conservation efforts. Here we first report on the sequence of events surrounding a crocodile arrival and death in the Southern Dutch Antilles in 2024, and discuss this along with three additional older records for the same island group. The results are then integrated regionally by discussing three remarkable crocodile records for the island of San Andr & eacute;s, Colombia, since 2012, and nine for the Cayman Islands since 2006. The findings indicate the species' ability to disperse hundreds of kilometers across the open sea to colonize new and/or former habitat. We conclude by arguing that the islands we discuss should also be considered part of the current natural range of occurrence of the species, even though this has generally not been acknowledged, and the few animals noticed have typically been persecuted. Finally, we urge island governments and conservation organizations to prepare awareness and action plans to accommodate this vulnerable and valuable top predator in the wild.

Rapid identification of invasive non-native species aids conservation efforts, particularly in threatened and vulnerable species. However, this can be extremely challenging for morphologically similar non-native and native species, especially for those with cryptic coloration and small home ranges. This holds for non-native green iguanas (NNGI; Iguana iguana), which threaten insular Iguana populations through displacement across the eastern Caribbean. Rapid identification of NNGI is critical to strengthen conservation efforts in native insular Iguana spp. Here we assessed whether ectoparasitic Geckobiella stamii mites of Iguana spp. are host-specific and could aid such efforts through rapid identification and monitoring of NNGI presence. We generated an mtDNA mite-iguana dataset for multiple native populations of Iguana delicatissima and the Iguana iguana complex, including islands with NNGI presence. To assess host specificity between different hosts, we also generated data from other reptiles on St. Eustatius. Phylogenies of native G. stamii COX1 and Iguana ND4 genes showed identical topologies with similar divergence patterns, highlighting their co-evolutionary host-parasite relation. On St. Eustatius, we found high divergences (> 22

Invasive alien species severely impact native and endemic species, disproportionately affecting insular species like Caribbean reptiles. The Lesser Antillean iguana, Iguana delicatissima, is rapidly declining due to hybridization with non-native green iguanas (NNGIs). With numerous NNGI populations present in the region, the last I. delicatisisma-inhabited islands remain highly susceptible to invasion, whereupon the rapid in situ differentiation of NNGIs is essential. However, currently only few scale and coloration characters allow the in situ identification of NNGIs. Here, we assessed the differentiating power of an additional 20 meristic and length-dependent characteristics between the I. delicatissima population on St. Eustatius and the NNGI population on St. Maarten, the main source of NNGIs arriving on St. Eustatius. Of these, 13 significantly differed between I. delicatissima and NNGIs, with a ≥94% assignment accuracy in multi-variate predictive models. We recommend that these characteristics be assessed and validated, especially for hybrid individuals, allowing the identification of NNGIs even in populations where hybridization is ongoing. Our work demonstrates the value of investing in baseline morphometric datasets for I. delicatissima and other native iguanas to aid in the rapid in situ detection of NNGIs for removal.

Invasive alien species severely impact native and endemic species, disproportionately affecting insular species, and this is especially true for Caribbean reptiles. The Lesser Antillean iguana ( Iguana delicatissima ) experienced a drastic range decline strongly driven by hybridization with non-native green iguanas (NNGI, Iguana iguana species complex). With numerous NNGI populations within the Lesser Antilles, it is a matter of time before these arrive on the last I. delicatisisma inhabited islands, whereupon rapid in-situ identification of non-native and hybrid animals is essential. However, only a few scale and coloration characters allow in-situ identification of NNGI, which are compromised by introgression. Here we assessed the differentiating power of an additional 20 scale and length-dependent characteristics between the I. delicatissima population on St. Eustatius and the established NNGI population on St. Maarten, the main source of arriving stowaway iguanas on St. Eustatius. We identified 14 length-dependent characteristics that significantly differ between I. delicatissima and NNGI’s, with multi-variate analysis showing clear morphospace separation and high assignment accuracy of predictive models (>91%). Additionally, the number of femorals and supra digital scales significantly differs between these iguanas. Morphospace knowledge of St. Eustatius’ I. delicatissima now allows rapid identification of any divergent iguanas using easy to obtain measurements and meristics. Given intraspecific variation in I. delicatissima and green iguanas, we recommend that these characteristics are assessed and validated for other populations, including hybrid individuals. Our work demonstrates the urgent need to invest in baseline morphometric datasets to aid rapid in-situ conservation efforts once NNGI arrive and start to hybridize with I. delicatissima . ### Competing Interest Statement The authors have declared no competing interest.

The conservation status of more than 160,000 species has been assessed following IUCN guidelines, with greater than 13% considered data deficient. Maintaining an accurate understanding of native populations is challenging, especially for species with geographically large or discontinuous insular ranges. Here we assessed a data deficient population of a critically endangered reptile within the Caribbean biodiversity hotspot. We surveyed the island of Antigua for three weeks to assess whether the native Iguana delicatissima remains present. Morphological data from 98 observed and 29 captured iguanas showed no sign of pure remaining I. delicatissima; whilst 19 individuals had some morphological features of I. delicatissima. Sequence data and discriminant analyses of 17 microsatellite loci assigned all captured iguanas to I. iguana, although the presence of two I. delicatissima alleles are indicative of an old introgressed population. The only present mtDNA haplotype matched to the non-native iguana population on Grand-Terre, Guadeloupe. This provides genetic evidence of hurricane-mediated translocation as proposed happened in the aftermath of two 1995 hurricanes when debris-rafts with iguanas landed on Anguilla, Barbuda, and Antigua. The rapid decline of I. delicatissima places urgency on finding and conserving any surviving remnant populations, which we show are likely absent from Antigua, though we cannot rule out the presence of a few individuals.

This study reviewed the state-of-the-art knowledge on Nypa fruticans-based (hereafter Nypa-based) land use along with the corresponding ecosystem services that contribute to the wellbeing of mangrove-dependent communities (MDCs) in the tropics. In relation to the land uses, Nypa’s ecosystem service valuation, restoration potential and threats were also explored. Nypa-based land uses documented in tropical countries since the last century include, Natural Nypa Forests (NNF), Nypa Plantations (NP), Nypa-Aquaculture Systems (NAS), and Nypa-Agriculture Systems (NAgS). Even though land use-specific variations were found in distribution, abundance, and ecosystem services provided, it appears that there is the great overlap of reported ecosystem services regardless of Nypa land use. The provisioning ecosystem services of Nypa have been made use of at the subsistence level by man for millennia. These especially include its use as a source of food, fuel, and fiber. Nypa is unique among the many mangroves as being about the only one that has significantly been developed for commercial exploitation beyond the typical destructive harvest for wood and charcoal as seen in most other mangroves. Our review presents new research that has made important inroads in exploring Nypa’s yet untapped commercial potential for livelihood provisioning for poor MDCs. Building further on these pioneering results holds major promise for the development of new sustainable livelihood opportunities for MDCs. The review also shows that Nypa provides substantial supporting, regulating and cultural services. These services have been rarely studied, and Nypa’s contribution to the wellbeing of MDCs are therefore not well-acknowledged. Our review also suggests that at the landscape level, Nypa also holds major promise as a way to rapidly sequester atmospheric carbon dioxide, protect coastal areas from weather extremes, rehabilitate abandoned aquaculture ponds and transform aquaculture towards greater sustainability. Therefore, we recommend further intensification of Nypa-based land uses in conjunction with the further development of value-added Nypa products for livelihood support, as well as basic research on the ecological niche-specific suitability of Nypa-based land uses, and their associated ecosystem services.

The Common House Gecko (Hemidactylus frenatus) is recently being reported from multiple islands across the Lesser Antilles: Antigua, Dominica, St. Barthélemy, St. Eustatius, St. Kitts, St. Lucia, and St. Martin (Brisbane et al. 2021, Dewynter et al. 2022, Griffing et al. 2022, Thorpe 2022, Questel et al. 2023, Thibaudier et al. 2023, Lindsay et al. 2023). Here, we report on the establishment of the species on Saba, Dutch Caribbean. On 27 November 2023, between 19.30–20.30 h, we surveyed buildings, walls, rock crevices and piles of wood, brick, concrete, and metal, including building supplies, on the Fort-Bay Road, adjacent to the Fort Bay harbor on Saba (17.61615, -63.25039). We found H. frenatus at eight locations along a 520-meter stretch of road, either on walls, next to the road between rocks, or between aforementioned materials. At each location one animal was captured, totaling four adults and four juveniles. The lamellae on the 4th and 5th digit were used to confirm species identity (Krysko and Daniels 2005). We collected one adult (Figure 1) that has been provided to Naturalis Biodiversity Center, Leiden, The Netherlands, for deposition in their collections. We note that Hemidactylus mabouia was also found at three sites within the 520-meter stretch, but never closer than ~30 meters to Hemidactylus frenatus, which is a known competitor of other gecko species (Petren & Case 1996).